饲养密度和饲粮营养影响肉鸡生长、胴体组成及腿部健康的研究
|
摘要
饲养密度与肉鸡福利密切相关,为了揭示不同性别肉鸡在不同饲养密度条件下的营养需求变化,本研究共设计了5个试验。
试验一旨在研究不同饲养密度和饲粮代谢能水平对肉鸡生长、胴体组成及腿部健康的影响。采用三因子(2性别×2饲养密度×2代谢能水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏876只和母雏1020只,随机分成8个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设高、低两个代谢能水平(HME和LME),其中,HME饲粮3期代谢能分别为2950、3050和3151kcal/kg, LME饲粮分别为2800、2900和3000kcal/kg。结果发现,高饲养密度(42kg/m2)显著降低肉鸡日增重和饲料效率(P<0.01)。在1～35日龄,高饲养密度显著降低肉鸡采食量(P<0.05),但在36～42日龄,结果正好相反(P<0.0001)。与母鸡相比,公鸡的采食量、日增重和饲料效率较高(P<0.001)。性别与饲养密度对肉鸡日增重和饲料效率存在互作效应(P<0.05),在1～35日龄,高饲养密度对公鸡日增重影响显著；在36-42日龄,高饲养密度对母鸡日增重和饲料效率影响显著。就生长性能而言,饲粮代谢能水平与肉鸡饲养密度或性别无互作效应(P>0.05)。饲养密度对肉鸡胸肌率、腿肌率和腹脂率没有显著影响,母鸡比公鸡具有较高的胸肌率和腹脂率(P<0.01)。公鸡和高饲养密度处理的脚垫损伤与步态评分较高,低代谢能饲粮只加剧脚垫损伤而不影响步态评分。这些结果表明,在35日龄之前,高饲养密度显著抑制公鸡生长；在即将上市时(36～42日龄),母鸡比单位面积体重(体重/m2)相同的公鸡需要更多空间。肉鸡腿病的发生率和严重度与性别、饲粮和饲养密度有关,应激反应至少应是高饲养密度削弱肉鸡生产性能的部分原因。
试验二旨在研究不同饲养密度和饲粮赖氨酸水平对肉鸡生长、胴体组成及腿部健康的影响。采用三因子(2性别×2饲养密度×3赖氨酸水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏1314只和母雏1530只,随机分成12个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设高、中、低3个赖氨酸添加水平,分别为NRC推荐标准的120%、100%和80%。结果发现,高饲养密度显著降低肉鸡日增重和饲料效率(P<0.01)。在1～35日龄,高饲养密度显著降低肉鸡采食量,但在36～42日龄,结果正好相反(P<0.01)。与母鸡相比,公鸡的采食量、日增重和饲料效率较高(P<0.01)。性别与饲养密度对肉鸡日增重和饲料效率存在互作效应(P<0.05),在1-35日龄,高饲养密度对公鸡日增重影响显著；在36～42日龄,高饲养密度对母鸡日增重和饲料效率影响显著。高饲养密度(P<0.05)和低赖氨酸饲粮(P<0.01)显著降低肉鸡的胸肌率,公鸡的胸肌率和腹脂率显著低于母鸡(P<0.01)。高饲养密度显著提高肉鸡步态和脚垫损伤评分,公鸡的步态评分显著高于母鸡(P<0.01)。以上研究结果表明,高饲养密度不能改变肉鸡的赖氨酸需求,它对于肉鸡的不利影响具有日龄和性别特异性。
试验三旨在研究不同饲养密度和饲粮维生素D3添加水平对公母分饲肉鸡生长性能和腿部健康的影响。采用三因子(2性别×2饲养密度×3维生素D3水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏1314只和母雏1530只,随机分成12个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设高、中、低3个维生素D3添加水平,分别为5500、3000和500IU/kg。结果发现,在高饲养密度条件下,肉鸡胫骨灰分减少,步态与脚垫损伤评分增加(JP<0.05)。饲粮添加维生素D3对肉鸡生长性能、胫骨灰分、钙、磷水平、步态和脚垫质量评分以及垫料水分含量无显著影响(P>0.05),饲养密度、饲粮维生素D3添加水平和肉鸡性别对于血磷的互作效应显著(P<0.01)。这些结果表明,高饲养密度降低肉鸡胫骨矿物质沉积,削弱行走能力,加重脚垫损伤。在饲粮钙磷供应充足条件下,提高饲粮维生素D3添加水平对肉鸡生产性能和腿部健康没有影响。要想缓解高饲养密度所带来的不利效应,需同时考虑维生素D3、饲粮钙磷水平和生产管理等因素。
试验四旨在研究不同饲养密度和饲粮钙磷水平对肉鸡生长和腿部健康的影响。采用三因子(2性别×2饲养密度×6钙磷添加水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏2628只和母雏3060只,随机分成24个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设(NCa, NP),(Ca+25%, NP)、(Ca+50%, NP)、(Ca-25%, NP-25%)、(Ca+25%,NP+25%)和(Ca+50%,NP+50%)6个钙磷水平,分别为正常钙磷浓度、仅钙浓度提高25%、仅钙浓度提高50%、钙磷浓度各降25%、钙磷浓度各升25%和钙磷浓度各升50%。结果发现,高饲养密度加重肉鸡腿部健康,提高垫料潮湿度,但不影响胫骨灰分、钙和磷含量。饲粮钙磷水平显著影响肉鸡生长性能和胫骨矿物沉积,但对步态和脚垫损伤没有影响。就步态和脚垫损伤评分而言,肉鸡饲养密度与饲粮钙磷水平的互作效应显著。以上结果表明,调控饲粮钙磷水平能够在一定程度上缓解高饲养密度所带来的不利影响。
试验五旨在研究不同饲养密度、饲粮生物素水平对公母混饲肉鸡生长性能、胴体组成、器官指数以及腿部健康的影响。采用三因子(2性别×2饲养密度×4生物素水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏1752只和母雏2040只,随机分成16个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg,/m2(LSD,10公或12母/m2)。饲粮生物素添加水平分别为0、0.20、0.40和0.60mg/kg。结果表明,公鸡的采食量、日增重和饲料效率高于母鸡(P<0.01),胴体率、胸肌率、腹脂率和肝脏指数低于母鸡(P<0.05)。高密度可降低肉鸡生长性能和胸肌率,提高胴体率和腿肌率(P<0.05)。在1-42日龄,高密度饲养对母鸡生长性能的影响更严重。饲粮生物素水平对生长性能和胴体指标无影响(P>0.05),但在1-7日龄,饲养密度和生物素水平存在微弱互作,饲粮中添加适宜水平的生物素可改善低密度肉鸡的料重比。生物素水平与性别对胴体率的交互作用显著(P<0.05),增加生物素水平,公鸡胴体率线性增加,而对母鸡影响不明显。就肉鸡腹脂率(P<0.05)而言,性别、饲养密度和饲粮生物素水平3者之间的互作效应显著,在饲粮中添加0.4mg,/kg生物素,可改善低密度条件下公鸡的腹脂率。公鸡的步态和跗关节损伤评分高于母鸡(P<0.05)。高密度肉鸡脚垫和步态评分及垫料水分均高于低密度(P<0.01)。饲粮生物素水平对肉鸡腿部健康和垫料水分无影响(P>0.05)。随着饲养密度的增加,公鸡的跗关节损伤评分增加,而母鸡的跗关节损伤评分降低。饲粮生物素水平与肉鸡饲养密度几无互作。以上结果表明,饲粮添加生物素不能缓解肉鸡高饲养密度所带来的不利影响。但在饲粮中添加适宜水平的生物素,可部分改善低密度条件下肉鸡饲料效率和公鸡的腹脂率。
综上所述,高饲养密度显著降低肉鸡日增重和饲料效率(P<0.01),显著提高肉鸡步态和脚垫损伤评分,加重肉鸡腿部健康,提高垫料潮湿度。饲养密度对肉鸡胸肌率、腿肌率和腹脂率没有显著影响。母鸡比公鸡具有较高的胸肌率和腹脂率(P<0.01)。公鸡的步态评分显著高于母鸡(P<0.01)。与低代谢能饲粮相比,高代谢能饲粮显著降低肉鸡采食量(P<0.01),提高日增重(P<0.01)和饲料效率(P<0.01)。低赖氨酸饲粮(P<0.01)显著降低肉鸡的胸肌率。与正常赖氨酸饲粮相比,低赖氨酸饲粮显著降低肉鸡采食量(P=0.01)、日增重(P<0.01)和饲料效率(P<0.01),高赖氨酸饲粮也显著降低肉鸡采食量、日增重和饲料效率(P<0.05)。饲粮钙磷水平显著影响肉鸡生产性能和胫骨矿物质沉积,但对步态和脚垫损伤没有影响。饲粮维生素D3添加水平对肉鸡胫骨矿物质沉积没有显著影响(P>0.05),对肉鸡生产性能、腿部健康、垫料质量和血液生化指标没有显著影响。饲粮生物素水平对肉鸡的生长性能和胴体组成无影响(P>0.05),饲粮中添加高水平的生物素可降低脚垫以及跗关节损伤。
Stocking density has critical implications for broiler welfare. In order to expose the nutrient requirement of broiler chickens with different density allowances in a sex dependent fashion,4trials were conducted in this comprehensive study.
In trial1, the effects of stocking density, sex and dietary metabolic energy (ME) concentration on the growth performance, footpad burns, and leg weakness were investigated.876male and1020female one day-old chicks were respectively placed into48pens to simulate final stocking density of26(10males or12females) and42(16males or18females) kg of BW/m2floor space. Two series of experimental diets with a150Kcal/kg difference in ME concentration (2800,2900and3000or2950,3050and3150Kcal ME/kg diet) were compared in a3-phase feeding program. High stocking density significantly (P<0.01) decreased average day gain (ADG) and feed to gain ratio (F/G). At high stocking density, chickens consumed less (P<0.05) feed by35d of age, thereafter the reverse was true (P<0.0001). Male chickens had significantly (P<0.001) higher average day feed intake (ADFI), ADG, and F/G compared with females. Stocking density and sex had a significant interaction for ADG and F/G By35d of age, ADG of male broilers was more severely affected by high stocking density. In contrast, females were more severely affected in ADG and F/G by high stocking density from36to42d of age. There was no interaction (P>0.05) between dietary ME level and stocking density or sex. Stocking density had no significant influence on breast, thigh or abdominal fat yield. Female broilers had significantly (P<0.01) higher breast yield and abdominal fat content. Male broilers and high stocking density had higher footpad burn and gait scores. Low ME diet increased footpad burn score rather than gait score. The result indicated that stocking density had more severe effect on the growth of male broilers before35d of age. Female broilers need more space than males at similar body weight/m2around marketing age. The incidence and severity of leg weakness are associated with sex, diet and stocking density. The result suggests that stress response should be responsible at least partially for the deteriorated performance by high stocking density.
In trial2, the effects of stocking density, sex and dietary lysine concentration on growth performance, carcass characteristics, footpad burns, and leg weakness of broilers were investigated.1314male and1530female days old chicks were respectively placed into72pens to simulate final stocking density treatments of26(LSD,10males or12females/m2) and42(HSD,16males or18 females/m2) kg of BW/m2floor space. Three series of experimental diets with a20%difference in lysine concentration (120%,100%, and80%of NRC recommendation) were compared in a3-phase feeding program. HSD treatment significantly decreased ADG and F/G (P<0.01). HSD chickens consumed less feed by35d of age, thereafter the reverse was true (P<0.01). Male chickens had significantly higher ADFI, ADG, F/G compared with females (P<0.01). Stocking density and sex had a significant interaction for ADG and F/G(P<0.05). By35d of age, the ADG of male broilers was more severely affected by HSD. In contrast, females were more severely affected in BW gain and F/G by HSD from36to42d of age. The breast muscle yield of broilers was significantly decreased by HSD (P<0.05) and low lysine diet (P<0.01). Female broilers had significantly (P<0.01) higher breast muscle yield and abdominal fat content. Male broilers and HSD treatment had high footpad burn and gait scores (P<0.01). These results suggest that the lysine requirement of broilers is not altered by stocking density, and the deteriorated effect of high stocking density is sex and age dependent.
In trial3, the effects of stocking density, sex and dietary vitamin D3concentration on live performance, leg health and litter quality were investigated.1314male and1530female day-old chicks were respectively placed into36pens to simulate final stocking density treatments of26(LSD,10males or12females/m2) and42(HSD,16males or18females/m2) kg of BW/m2floor space. Three series of experimental diets with a2500IU/kg difference in vitamin D3concentration (500,3000and5500IU/kg) were compared in a3-phase feeding program. Results showed that HSD significantly (P<0.05) decreased tibial mineral deposition, while increasing gait and footpad burn scores. Increasing dietary vitamin D3had no influence on growth performance, tibial ash, Ca and P, gait and footpad burn scores, and litter moisture (P>0.05). The interaction of stocking density, dietary vitamin D3, and sex was significant on plasma P concentrations (P<0.01). These results suggest that HSD inhibits tibial development, impairs walking ability, and aggravates footpad burn. A phosphorus-adequate diet used in the present study likely explains the poor result of increasing dietary vitamin D3. In fact, vitamin D3improves the growth of broilers by increasing phytate phosphorus utilization, so its positive effect on performance is exerted almost exclusively in phosphorus-deficient diets.
In trial4, the effects of stocking density, sex and dietary calcium and phosphorus concentration on growth performance, tibial parameters, litter quality, footpad burns, and leg weakness of broilers were investigated,2628male and3060female one day-old chicks were respectively placed into144pens to simulate final stocking density treatments of26(LSD,10males or12females/m2) and42(HSD,16males or18females/m2) kg of BW/m2floor space. Six series of experimental diets with a25%difference in calcium and phosphorus concentration [(NCa, NP),(Ca+25%, NP),(Ca+50%, NP),(Ca-25%, NP-25%),(Ca+25%, NP+25%) and (Ca+50%, NP+50%)] were compared in a3-phase feeding program. Results showed that HSD aggravated leg weakness, increased litter moisture, but didn't affect tibial ash, calcium and phosphorus content. Dietary calcium and phosphorus level had a significant influence on growth performance, tibial ash and phosphorus content, but not on gait and footpad burn scores. Stocking density and dietary calcium and phosphorus level had a significant interaction for gait and footpad burn scores. These results suggest that dietary calcium and phosphorus may alleviate the negative effect of high stocking density to some extent.
In trial5, the effects of stocking density, sex and dietary biotin levels on the growth performance, leg health, and litter quality were investigated.1752male and2040female day-old chicks were respectively placed into48pens to simulate final stocking density of26(10males or12females) and42(16males or18females) kg of BW/m2floor space. Four series of experimental diets with a0.20mg/kg difference in biotin concentration (0,0.20,0.40or0.60mg/kg diet) were compared in a3-phase feeding program. High dietary levels of biotin had no influence on growth performance and carcass characteristics (P>0.05). Biotin and sex had a significant interaction for carcass and liver yields (P<0.05). The interaction of stocking density, dietary biotin, and sex was significant on abdominal fat content (P<0.05). High dietary concentrations of biotin did not affect litter moisture, and gait, footpad and hock burn scores, and had no interaction with stocking density (P>0.05). These results indicate that the growth response to dietary biotin differs between male and female chickens. High levels of biotin are favorable for lower fatness in broiler chickens reared at low density. The effect of increasing dietary biotin on leg health is dependent on the condition of the litter. It is impossible that high inclusion rates of supplementary biotin may contribute to the healing of leg weakness if litter moisture is greater than40%.
These results show that HSD significant reduced ADG and F/G (P<0.01), improved gait and footpad burn scores (P<0.01), had negative effect on leg health and litter moisture. Stocking density had no significant influence on breast, thigh or abdominal fat yield. Female broilers had significantly (P<0.01) higher breast yield and abdominal fat content. Male broilers had higher gait scores. HME significant reduced average ADFI, ADG, F/G (P<0.01). The breast muscle yield of broilers was significantly decreased by low lysine diet (P<0.01). ADFI (P=0.01), ADG(P<0.01) and F/G (P<0.01)were significantly decreased by low lysine diet (P<0.01). And the ADFI, ADG and F/G were also significantly decreased by high lysine diet (P<0.01). Dietary calcium and phosphorus level had a significant influence on growth performance, tibial ash and phosphorus content, but not on gait and footpad burn scores. Dietary vitamin D3had no significant influence on tibial ash and phosphorus content, Dietary vitamin D3had no significant influence on growth performance, leg health, litter moisture and plasma metabolites (P>0.05). Dietary biotin had no effect on growth performance and carcass (P>0.05), high level of biotin was contribute to the footpad burn scores and tarsal joint injury.
试验一旨在研究不同饲养密度和饲粮代谢能水平对肉鸡生长、胴体组成及腿部健康的影响。采用三因子(2性别×2饲养密度×2代谢能水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏876只和母雏1020只,随机分成8个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设高、低两个代谢能水平(HME和LME),其中,HME饲粮3期代谢能分别为2950、3050和3151kcal/kg, LME饲粮分别为2800、2900和3000kcal/kg。结果发现,高饲养密度(42kg/m2)显著降低肉鸡日增重和饲料效率(P<0.01)。在1～35日龄,高饲养密度显著降低肉鸡采食量(P<0.05),但在36～42日龄,结果正好相反(P<0.0001)。与母鸡相比,公鸡的采食量、日增重和饲料效率较高(P<0.001)。性别与饲养密度对肉鸡日增重和饲料效率存在互作效应(P<0.05),在1～35日龄,高饲养密度对公鸡日增重影响显著；在36-42日龄,高饲养密度对母鸡日增重和饲料效率影响显著。就生长性能而言,饲粮代谢能水平与肉鸡饲养密度或性别无互作效应(P>0.05)。饲养密度对肉鸡胸肌率、腿肌率和腹脂率没有显著影响,母鸡比公鸡具有较高的胸肌率和腹脂率(P<0.01)。公鸡和高饲养密度处理的脚垫损伤与步态评分较高,低代谢能饲粮只加剧脚垫损伤而不影响步态评分。这些结果表明,在35日龄之前,高饲养密度显著抑制公鸡生长；在即将上市时(36～42日龄),母鸡比单位面积体重(体重/m2)相同的公鸡需要更多空间。肉鸡腿病的发生率和严重度与性别、饲粮和饲养密度有关,应激反应至少应是高饲养密度削弱肉鸡生产性能的部分原因。
试验二旨在研究不同饲养密度和饲粮赖氨酸水平对肉鸡生长、胴体组成及腿部健康的影响。采用三因子(2性别×2饲养密度×3赖氨酸水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏1314只和母雏1530只,随机分成12个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设高、中、低3个赖氨酸添加水平,分别为NRC推荐标准的120%、100%和80%。结果发现,高饲养密度显著降低肉鸡日增重和饲料效率(P<0.01)。在1～35日龄,高饲养密度显著降低肉鸡采食量,但在36～42日龄,结果正好相反(P<0.01)。与母鸡相比,公鸡的采食量、日增重和饲料效率较高(P<0.01)。性别与饲养密度对肉鸡日增重和饲料效率存在互作效应(P<0.05),在1-35日龄,高饲养密度对公鸡日增重影响显著；在36～42日龄,高饲养密度对母鸡日增重和饲料效率影响显著。高饲养密度(P<0.05)和低赖氨酸饲粮(P<0.01)显著降低肉鸡的胸肌率,公鸡的胸肌率和腹脂率显著低于母鸡(P<0.01)。高饲养密度显著提高肉鸡步态和脚垫损伤评分,公鸡的步态评分显著高于母鸡(P<0.01)。以上研究结果表明,高饲养密度不能改变肉鸡的赖氨酸需求,它对于肉鸡的不利影响具有日龄和性别特异性。
试验三旨在研究不同饲养密度和饲粮维生素D3添加水平对公母分饲肉鸡生长性能和腿部健康的影响。采用三因子(2性别×2饲养密度×3维生素D3水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏1314只和母雏1530只,随机分成12个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设高、中、低3个维生素D3添加水平,分别为5500、3000和500IU/kg。结果发现,在高饲养密度条件下,肉鸡胫骨灰分减少,步态与脚垫损伤评分增加(JP<0.05)。饲粮添加维生素D3对肉鸡生长性能、胫骨灰分、钙、磷水平、步态和脚垫质量评分以及垫料水分含量无显著影响(P>0.05),饲养密度、饲粮维生素D3添加水平和肉鸡性别对于血磷的互作效应显著(P<0.01)。这些结果表明,高饲养密度降低肉鸡胫骨矿物质沉积,削弱行走能力,加重脚垫损伤。在饲粮钙磷供应充足条件下,提高饲粮维生素D3添加水平对肉鸡生产性能和腿部健康没有影响。要想缓解高饲养密度所带来的不利效应,需同时考虑维生素D3、饲粮钙磷水平和生产管理等因素。
试验四旨在研究不同饲养密度和饲粮钙磷水平对肉鸡生长和腿部健康的影响。采用三因子(2性别×2饲养密度×6钙磷添加水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏2628只和母雏3060只,随机分成24个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg/m2(LSD,10公或12母/m2)。饲粮分阶段配制,设(NCa, NP),(Ca+25%, NP)、(Ca+50%, NP)、(Ca-25%, NP-25%)、(Ca+25%,NP+25%)和(Ca+50%,NP+50%)6个钙磷水平,分别为正常钙磷浓度、仅钙浓度提高25%、仅钙浓度提高50%、钙磷浓度各降25%、钙磷浓度各升25%和钙磷浓度各升50%。结果发现,高饲养密度加重肉鸡腿部健康,提高垫料潮湿度,但不影响胫骨灰分、钙和磷含量。饲粮钙磷水平显著影响肉鸡生长性能和胫骨矿物沉积,但对步态和脚垫损伤没有影响。就步态和脚垫损伤评分而言,肉鸡饲养密度与饲粮钙磷水平的互作效应显著。以上结果表明,调控饲粮钙磷水平能够在一定程度上缓解高饲养密度所带来的不利影响。
试验五旨在研究不同饲养密度、饲粮生物素水平对公母混饲肉鸡生长性能、胴体组成、器官指数以及腿部健康的影响。采用三因子(2性别×2饲养密度×4生物素水平)完全随机试验设计,选用Ross308商品肉仔鸡公雏1752只和母雏2040只,随机分成16个处理,每个处理6个重复。试验设高、低两个饲养密度,以出栏体重计,分别为42kg/m2(HSD,16公或18母/m2)和26kg,/m2(LSD,10公或12母/m2)。饲粮生物素添加水平分别为0、0.20、0.40和0.60mg/kg。结果表明,公鸡的采食量、日增重和饲料效率高于母鸡(P<0.01),胴体率、胸肌率、腹脂率和肝脏指数低于母鸡(P<0.05)。高密度可降低肉鸡生长性能和胸肌率,提高胴体率和腿肌率(P<0.05)。在1-42日龄,高密度饲养对母鸡生长性能的影响更严重。饲粮生物素水平对生长性能和胴体指标无影响(P>0.05),但在1-7日龄,饲养密度和生物素水平存在微弱互作,饲粮中添加适宜水平的生物素可改善低密度肉鸡的料重比。生物素水平与性别对胴体率的交互作用显著(P<0.05),增加生物素水平,公鸡胴体率线性增加,而对母鸡影响不明显。就肉鸡腹脂率(P<0.05)而言,性别、饲养密度和饲粮生物素水平3者之间的互作效应显著,在饲粮中添加0.4mg,/kg生物素,可改善低密度条件下公鸡的腹脂率。公鸡的步态和跗关节损伤评分高于母鸡(P<0.05)。高密度肉鸡脚垫和步态评分及垫料水分均高于低密度(P<0.01)。饲粮生物素水平对肉鸡腿部健康和垫料水分无影响(P>0.05)。随着饲养密度的增加,公鸡的跗关节损伤评分增加,而母鸡的跗关节损伤评分降低。饲粮生物素水平与肉鸡饲养密度几无互作。以上结果表明,饲粮添加生物素不能缓解肉鸡高饲养密度所带来的不利影响。但在饲粮中添加适宜水平的生物素,可部分改善低密度条件下肉鸡饲料效率和公鸡的腹脂率。
综上所述,高饲养密度显著降低肉鸡日增重和饲料效率(P<0.01),显著提高肉鸡步态和脚垫损伤评分,加重肉鸡腿部健康,提高垫料潮湿度。饲养密度对肉鸡胸肌率、腿肌率和腹脂率没有显著影响。母鸡比公鸡具有较高的胸肌率和腹脂率(P<0.01)。公鸡的步态评分显著高于母鸡(P<0.01)。与低代谢能饲粮相比,高代谢能饲粮显著降低肉鸡采食量(P<0.01),提高日增重(P<0.01)和饲料效率(P<0.01)。低赖氨酸饲粮(P<0.01)显著降低肉鸡的胸肌率。与正常赖氨酸饲粮相比,低赖氨酸饲粮显著降低肉鸡采食量(P=0.01)、日增重(P<0.01)和饲料效率(P<0.01),高赖氨酸饲粮也显著降低肉鸡采食量、日增重和饲料效率(P<0.05)。饲粮钙磷水平显著影响肉鸡生产性能和胫骨矿物质沉积,但对步态和脚垫损伤没有影响。饲粮维生素D3添加水平对肉鸡胫骨矿物质沉积没有显著影响(P>0.05),对肉鸡生产性能、腿部健康、垫料质量和血液生化指标没有显著影响。饲粮生物素水平对肉鸡的生长性能和胴体组成无影响(P>0.05),饲粮中添加高水平的生物素可降低脚垫以及跗关节损伤。
Stocking density has critical implications for broiler welfare. In order to expose the nutrient requirement of broiler chickens with different density allowances in a sex dependent fashion,4trials were conducted in this comprehensive study.
In trial1, the effects of stocking density, sex and dietary metabolic energy (ME) concentration on the growth performance, footpad burns, and leg weakness were investigated.876male and1020female one day-old chicks were respectively placed into48pens to simulate final stocking density of26(10males or12females) and42(16males or18females) kg of BW/m2floor space. Two series of experimental diets with a150Kcal/kg difference in ME concentration (2800,2900and3000or2950,3050and3150Kcal ME/kg diet) were compared in a3-phase feeding program. High stocking density significantly (P<0.01) decreased average day gain (ADG) and feed to gain ratio (F/G). At high stocking density, chickens consumed less (P<0.05) feed by35d of age, thereafter the reverse was true (P<0.0001). Male chickens had significantly (P<0.001) higher average day feed intake (ADFI), ADG, and F/G compared with females. Stocking density and sex had a significant interaction for ADG and F/G By35d of age, ADG of male broilers was more severely affected by high stocking density. In contrast, females were more severely affected in ADG and F/G by high stocking density from36to42d of age. There was no interaction (P>0.05) between dietary ME level and stocking density or sex. Stocking density had no significant influence on breast, thigh or abdominal fat yield. Female broilers had significantly (P<0.01) higher breast yield and abdominal fat content. Male broilers and high stocking density had higher footpad burn and gait scores. Low ME diet increased footpad burn score rather than gait score. The result indicated that stocking density had more severe effect on the growth of male broilers before35d of age. Female broilers need more space than males at similar body weight/m2around marketing age. The incidence and severity of leg weakness are associated with sex, diet and stocking density. The result suggests that stress response should be responsible at least partially for the deteriorated performance by high stocking density.
In trial2, the effects of stocking density, sex and dietary lysine concentration on growth performance, carcass characteristics, footpad burns, and leg weakness of broilers were investigated.1314male and1530female days old chicks were respectively placed into72pens to simulate final stocking density treatments of26(LSD,10males or12females/m2) and42(HSD,16males or18 females/m2) kg of BW/m2floor space. Three series of experimental diets with a20%difference in lysine concentration (120%,100%, and80%of NRC recommendation) were compared in a3-phase feeding program. HSD treatment significantly decreased ADG and F/G (P<0.01). HSD chickens consumed less feed by35d of age, thereafter the reverse was true (P<0.01). Male chickens had significantly higher ADFI, ADG, F/G compared with females (P<0.01). Stocking density and sex had a significant interaction for ADG and F/G(P<0.05). By35d of age, the ADG of male broilers was more severely affected by HSD. In contrast, females were more severely affected in BW gain and F/G by HSD from36to42d of age. The breast muscle yield of broilers was significantly decreased by HSD (P<0.05) and low lysine diet (P<0.01). Female broilers had significantly (P<0.01) higher breast muscle yield and abdominal fat content. Male broilers and HSD treatment had high footpad burn and gait scores (P<0.01). These results suggest that the lysine requirement of broilers is not altered by stocking density, and the deteriorated effect of high stocking density is sex and age dependent.
In trial3, the effects of stocking density, sex and dietary vitamin D3concentration on live performance, leg health and litter quality were investigated.1314male and1530female day-old chicks were respectively placed into36pens to simulate final stocking density treatments of26(LSD,10males or12females/m2) and42(HSD,16males or18females/m2) kg of BW/m2floor space. Three series of experimental diets with a2500IU/kg difference in vitamin D3concentration (500,3000and5500IU/kg) were compared in a3-phase feeding program. Results showed that HSD significantly (P<0.05) decreased tibial mineral deposition, while increasing gait and footpad burn scores. Increasing dietary vitamin D3had no influence on growth performance, tibial ash, Ca and P, gait and footpad burn scores, and litter moisture (P>0.05). The interaction of stocking density, dietary vitamin D3, and sex was significant on plasma P concentrations (P<0.01). These results suggest that HSD inhibits tibial development, impairs walking ability, and aggravates footpad burn. A phosphorus-adequate diet used in the present study likely explains the poor result of increasing dietary vitamin D3. In fact, vitamin D3improves the growth of broilers by increasing phytate phosphorus utilization, so its positive effect on performance is exerted almost exclusively in phosphorus-deficient diets.
In trial4, the effects of stocking density, sex and dietary calcium and phosphorus concentration on growth performance, tibial parameters, litter quality, footpad burns, and leg weakness of broilers were investigated,2628male and3060female one day-old chicks were respectively placed into144pens to simulate final stocking density treatments of26(LSD,10males or12females/m2) and42(HSD,16males or18females/m2) kg of BW/m2floor space. Six series of experimental diets with a25%difference in calcium and phosphorus concentration [(NCa, NP),(Ca+25%, NP),(Ca+50%, NP),(Ca-25%, NP-25%),(Ca+25%, NP+25%) and (Ca+50%, NP+50%)] were compared in a3-phase feeding program. Results showed that HSD aggravated leg weakness, increased litter moisture, but didn't affect tibial ash, calcium and phosphorus content. Dietary calcium and phosphorus level had a significant influence on growth performance, tibial ash and phosphorus content, but not on gait and footpad burn scores. Stocking density and dietary calcium and phosphorus level had a significant interaction for gait and footpad burn scores. These results suggest that dietary calcium and phosphorus may alleviate the negative effect of high stocking density to some extent.
In trial5, the effects of stocking density, sex and dietary biotin levels on the growth performance, leg health, and litter quality were investigated.1752male and2040female day-old chicks were respectively placed into48pens to simulate final stocking density of26(10males or12females) and42(16males or18females) kg of BW/m2floor space. Four series of experimental diets with a0.20mg/kg difference in biotin concentration (0,0.20,0.40or0.60mg/kg diet) were compared in a3-phase feeding program. High dietary levels of biotin had no influence on growth performance and carcass characteristics (P>0.05). Biotin and sex had a significant interaction for carcass and liver yields (P<0.05). The interaction of stocking density, dietary biotin, and sex was significant on abdominal fat content (P<0.05). High dietary concentrations of biotin did not affect litter moisture, and gait, footpad and hock burn scores, and had no interaction with stocking density (P>0.05). These results indicate that the growth response to dietary biotin differs between male and female chickens. High levels of biotin are favorable for lower fatness in broiler chickens reared at low density. The effect of increasing dietary biotin on leg health is dependent on the condition of the litter. It is impossible that high inclusion rates of supplementary biotin may contribute to the healing of leg weakness if litter moisture is greater than40%.
These results show that HSD significant reduced ADG and F/G (P<0.01), improved gait and footpad burn scores (P<0.01), had negative effect on leg health and litter moisture. Stocking density had no significant influence on breast, thigh or abdominal fat yield. Female broilers had significantly (P<0.01) higher breast yield and abdominal fat content. Male broilers had higher gait scores. HME significant reduced average ADFI, ADG, F/G (P<0.01). The breast muscle yield of broilers was significantly decreased by low lysine diet (P<0.01). ADFI (P=0.01), ADG(P<0.01) and F/G (P<0.01)were significantly decreased by low lysine diet (P<0.01). And the ADFI, ADG and F/G were also significantly decreased by high lysine diet (P<0.01). Dietary calcium and phosphorus level had a significant influence on growth performance, tibial ash and phosphorus content, but not on gait and footpad burn scores. Dietary vitamin D3had no significant influence on tibial ash and phosphorus content, Dietary vitamin D3had no significant influence on growth performance, leg health, litter moisture and plasma metabolites (P>0.05). Dietary biotin had no effect on growth performance and carcass (P>0.05), high level of biotin was contribute to the footpad burn scores and tarsal joint injury.
引文
陈娟,王安,张淑云,郭丽.饲粮钙和维生素D3水平对肉仔鸡生长性能、屠宰性能和肉品质的影响.动物营养学报,2010,22(6)：1544-1550.
初晓娜,汪以真,刘光富,朱连勤.高磷饲粮对肉仔鸡体组织钙、磷、镁含量的影响.中国饲料,2004,8：15-18.
丁角立,孙启军,朱玉琴,周毓平.饲粮中钙磷水平对肉用仔鸡生长性能及机体钙磷含量的影响.中国畜牧杂志,1994,5：6-9.
冯永淼,闫素梅,张海琴,史彬林,曹平.维生素A、D及其相互作用对肉仔鸡生长性能及组织维生素A、E浓度的影响.动物营养学报,2007,19(4)：411-416.
耿爱莲.规模饲养环境条件对肉鸡健康、福利以及鸡肉品质的影响.中国家禽,2007,(04).
呙于明,周毓平,丁角立.饲粮赖氨酸、蛋氨酸水平对肉鸡胴体组成的影响.动物营养学报,1989,1(1)：35-40.
呙于明,邵宪萍,丁角立,朱玉琴,周毓平.生长后期饲粮钙磷水平对肉仔鸡生长性能及胫骨矿化度的影响.中国饲料,1995,13：10-11.
龚月生,王志有,姚清东.赖氨酸水平和性别对肉仔鸡胴体品质的影响.动物营养学报,1993,5(1)：63-69.
韩春芳,蔡辉益,于会民,曹社会.不同生物素添加水平对肉仔鸡免疫器官发育和免疫功能的影响.西北农林科技大学学报(自然科学版),2005,33(11)：61-66.
丁角立,孙启军,朱玉琴,等.饲粮中钙磷水平对肉用仔鸡生产性能及机体钙磷含量的影响[J]中国畜牧杂志,1994,30(5)：6-9.
李健,侯水生,黄俊纯.肉仔鸡生物素缺乏症的观测及生物素需要量的探讨.畜牧兽医学报,1994,25(4)：295-300.
林勇,徐忠宝.饲料钙磷比对肉用仔鸡体内钙磷比影响的研究.畜牧与兽医,1997,29(3)：114.
刘光富,汪以真,朱连勤,初晓娜.2003.饲喂高磷饲粮对肉仔鸡机体组织钙、磷含量的影响.饲料博览,8：16-18.
卢菁,冯定远,邓跃林.饲粮磷水平对肉用小鸡生长性能的影响.广东饲料,2000,9：15-16.
马现永,蒋宗勇,林映才,周桂莲,张罕星.钙和维生素D3对黄羽肉鸡肌肉嫩度的影响及机理.动物营养学报,2009,21(3)：356-362.
石天虹,张桂芝,黄保华,刘雪兰,井庆川,武彬,魏祥法,刘瑞亭,闫佩佩.低能低蛋白条件下饲粮维生素D3对0-6周龄肉仔鸡影响的研究.家禽科学,2010,12：9-13.
赵宇,施正香,赵芙蓉,周东,董泰丽,隋锡兰.音乐及饲养密度对肉杂鸡生产及屠宰性能影响初探.农业工程学报,2006,22：155-158.
周林.生物素和维生素E对肉鸡屠宰性能和肉品质的影响.饲料博览,2000,8：6-7.
张海琴.维生素A、D对肉鸡生长、免疫、钙磷代谢的影响及其交互作用的研究.硕士学位论文.呼和浩特：内蒙古农业大学.2006.
张征.饲粮钙过量对雏鸡的影响.畜禽与禽病防疫,1996,7：34.
仲明,郑家佐.产蛋高峰期饲粮中钙磷水平对产蛋鸡胫骨强度及产蛋性能的影响[J].新疆畜牧业,2000,3：15-17.
朱连勤,朱风华,王清吉,张宗敏,巩青军,谭翠英,王善淑..低磷饲粮对产蛋鸡生长性能及脏器组织磷含量的影响.中国家禽,2000,9：7-10.
Abd El-Wahab, A., C. F. Visscher, A. Beineke, M. Beyerbach, and J. Kamphues.2011. Effects of floor heating and litter quality on the development and severity of foot pad dermatitis in young turkeys. Avian Dis.55:429-434.
Abd El-Wahab, A., C. F. Visscher, A. Beineke, M. Beyerbach, and J. Kamphues.2013a. Effects of high electrolyte contents in the diet and using floor heating on development and severity of foot pad dermatitis in young turkeys. J. Anim. Physiol. Anim. Nutr.97:39-47.
Abd El-Wahab, A., C. F. Visscher, S. Wolken, J.-M. Reperant, A. Beineke, M. Beyerbach, and J. Kamphues.2013b. Outcome of an artificial coccidial infection in poults under the influence of floor heating. Poult. Sci.92:629-637.
Abd El-Wahab, A., C. F. Visscher, S. Wolken, J.-M. Reperant, A. Beineke, M. Beyerbach, and J. Kamphues.2012. Foot pad dermatitis and experimentally induced coccidiosis in young turkeys fed a diet without anticoccidia. Poult. Sci.91:627-635.
Abd El-Wahab, A., D. Radko, and J. Kamphues.2013c. High dietary levels of biotin and zinc to improve health of foot pads in broilers exposed experimentally to litter with critical moisture content. Poult. Sci.92:1774-1782.
Andrews, S. M., H. M. Omed, and C. J. C. Phillips.1997. The effect of a single or repeated period of high stocking densityon the behavior and response to stimuli in broiler chickens. Poult. Sci. 76:1655-1660.
Angel, R., T. J. Applegate, and M. Christman.2000. Effects of dietary nonphytate phosphorus on performance and bone measurements in broilers fed on a four phase feeding system. Poult. Sci. 79(Suppl.1):21-22.
AOAC,1996. Moisture in Animal Feed. Method 930.15 in Official Methods of Analysis of AOAC International.16th ed. AOAC International, Gaithersburg, MD.
Arnould, U., and J. M. Faure.2003. Use of pen space and activity of broiler chickens reared at two different densities. Appl. Anim. Behav. Sci.84:281-296.
Atencio, A., H. M. Edwards Jr., G M. Pesti, and G. O. Ware.2006. The vitamin D3 requirement of broiler breeders. Poult. Sci.85:674-692.
Atencio A, Edw ards H M Jr, Pesti G M. Effect of the leve l o f cho leca lcifer olsupplementation of broiler breeder hen diets on the performance and bone abnorma lities of the progeny fed diets containing various levels of calcium or 25-hydroxy cholecalciferol[J]. Poultry Science,2005, 84(10):1593-1603.
Atteh J O, Leeson S. Influence of increasing the calium and magnesium content of the drinking water on performance and bone and plasma minerals of broiler chickens[J]. Poultry Science,1983, 62(5):869-874.
Bain S. D., J. W. Newbrey, B. A. Watkins. Biotin deficiency may alter tibiotarsal bone growth and modeling in broiler chicks. Poultry Science,1988,67(4):590-595.
Beloor, J., H. K. Kang, Y. J. Kim, V. K. Subramani, I. S. Jang, and S. H. Sohn. The effect of stocking density on stress related genes and telomeric length in broiler chickens. Asian-Aus. J. Anim. Sci.2010,23:437-443.
Berg, C. C.1998. Foot-pad dermatitis in broilers and turkeys-Prevalence, risk factors and prevention. PhD Diss. Swedish Univ. Agric. Sci., Skara.
Biehl, R. R., and D. H. Baker.1997. Utilization of phytate and nonphytate phosphorus in chicks as affected by source and amount of vitamin D3. J. Anim. Sci.75:2986-2993.
Bilgili, S. F., and J. B. Hess.1995. Placement density influences broiler carcass grade and meat yields. J. Appl. Poult. Res.4:384-389.
Bilgili, S. F., M. A. Alley, J. B. Hess, and M. Nagaraj.2006. Influence of age and sex on footpad quality and yield in broiler chickens reared on low and high density diets. J. Appl. Poult. Sci. 15:433-441
Bilgili, S. F.2009. Factors contributing to foot pad dermatitis in broilers. Watt Poultry USA, pp. 26-27.
Bolton W., W. A. Dewar, R. Morley Jones and R. Thompson. Effect of stocking density on performance of broiler chicks. British Poultry Science,1972,13:157-162.
Bolton, W., R. Thompson, R. M. Jones, and W. A. Dewar.1972. Effect of stocking density on performance of broiler chicks. Br. Poult. Sci.13:157-162.1. Chen X, and E. T. Moran.1995. The withdrawal feed of broilers:Carcass responses to dietary phosphorus. J. Appl. Poult. Res. 4:69-82.
Broz J, Olda le P, Perr in Vo ltz A H, et al. Effects of supplemental phytase on performance and pho sphorus utilisation in broiler chickens fed a low phosphorus diet without addition of inorganic pho sphates[J]. British Poultry Science,1994,35(3):273-280.
Buda, S.2000. Effects of biotin on the skin of turkey foot pads. World Poult.16:47-48.
Collins, L. M., and D. J. T. Sumpter.2007. The feeding dynamics of broiler chickens. J. R. Soc. Interface 4:65-72.
Cornetto, T. L., and I. Estevez.2001. Behavior of the domestic fowl in presence of vertical panels. Poult. Sci.80:1455-1462.
Cornetto, T., I. Estevez, and L. W. Douglass.2002. Using artificial cover to reduce aggression and disturbances in domestic fowl. Appl. Anim. Behav. Sci.75:325-336.
Cravener, T. L., W. B. Roush, and M. M. Mashaly.1992. Broiler production under varying population-densities. Poult. Sci.71:427-433.
Dawkins, M. S., C. A. Donnelly, and T. A. Jones.2004. Chicken welfare is influenced more by housing conditions than by stocking density. Nature 427:342-344.
Dawkins M S, Hardie S. Space needs of laying hens [J].British Poultry Science,1989,30:413-416.
Deaton, J. W., F. N. Reece, and T. H. Vardaman.1968. Effect of temperature and density on broiler performance. Poult. Sci.47:293-300.
Dhandu A S, Angel R. Broiler nonphytin phosphorus requirement in the finisher and withdrawal phases of acommercia I four-phase feeding system[J].Poultry Science,2003,82(8):1257-1265.
Dozier, W. A., B. D. Lott, and S. L. Branton.2005a. Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point. Poult. Sci. 84:1328-1331.
Dozier, W. A., J. P. Thaxton, S. L. Branton, G. W. Morgan, D. M. Miles, W. B. Roush, B. D. Lott, and Y. Vizzier-Thaxton.2005b. Stocking density effects on growth performance and processing yields of heavy broilers. Poult. Sci.84:1332-1338.
Dozier, W. A., J. P. Thaxton, J. L. Purswell, H. A. Olanrewaju, S. L. Branton, and W. B. Roush.2006. Stocking density effects on male broilers grown to 1.8 kilograms of BW. Poult. Sci.85:344-351.
Driver, J. P., A. Atencio, G. M. Pesti, H. M. Edwards, Jr., and R. I Bakalli.2006. The effect of maternal dietary vitamin D3 supplementation on performance and tibial dyschondroplasia of broiler chicks. Poult. Sci.85:39-47.
Driver, J. P., G. M. Pesti, R. I. Bakalli, and H. M. Edwards Jr.2005. Phytase and 1α-hydroxycholecalciferol supplementation of broiler chickens during the starting and growing/finishing phases. PouIt.Sci.84:1616-1628. Dawkins, M. S., C. A. Donnelly, and T. A. Jones.2004. Chicken welfare is influenced more by housing conditions than by stocking density. Nature 427:342-344.
Edwards, H. M., R. B. Shirley, A. Atencio, and G. M. Pesti.2004. Effect of dietary Ca levels on the efficacy of 1-α-hydroxycholecalciferol in the diets of young broilers. in World's Poult. Congr. Exhib. Istanbul, Turkey:494.
Edwards, H. M., Jr.2002. Studies on the Efficacy of cholecalciferol and derivatives for stimulating phytate utilization in broilers. Poult. Sci.81:1026-1031.
Ekstrand, C.1993. Effects of stocking density on the health, behaviour and productivity of broilers, a literature review. Swedish Univ. Agric. Sci., Skara.
Ekstrand, C., B. Algers, and J. Svedberg.1997. Rearing conditions and foot-pad dermatitis in Swedish broiler chickens. Prev. Vet. Med.31:167-174.
Ekstrand, C., and T. E. Carpenter.1998. Temporal aspects of foot-pad dermatitis in Swedish broilers. Acta Vet. Scand.39:229-236.
Elfadil, A. A., J. P. Vaillancourt, and A. H. Meek.1996. Impact of stocking density, breed, and feathering on the prevalence of abdominal skin scratches in broiler chickens. Avian Dis. 40:546-552.
Estevez, I.1994. Efecto del tamano de grupo y de las condiciones de manejo en el comportamiento y uso del espacio del gallo dome'stico (Gallus gallus). PhD Diss. Univ. Co'rdoba, Spain.
Estevez, I.1999. Density:How it can affect the behavior and health of your birds. Fact Sheet,758, Maryland Coop. Ext., Univ. Maryland.
Estevez, I., R. C. Newberry, and L. Arias de Reyna.1997. Broiler chickens:A tolerant social system Etologia 5:19-29.
Estevez, I.2007. Density allowances for broilers:where to set the limits. Poult.Sci.86:1265-1272.
Febrer, K., T. A. Jones, C. A. Donnelly, and M. S. Dawkins.2006. Forced to crowd or choosing to cluster Spatial distribution indicates social attraction in broiler chickens. Anim. Behav. 72:1291-1300.
Feddes, J. J. R., E. J. Emmanuel, and M. J. Zuidhof.2002. Broiler performance, BW variance, feed and water intake, and carcass quality at different stocking densities. Poult. Sci.81:774-779.
Food Market Institute-National Council of Chain Restaurants.2003. FMI-NCCR Animal welfare program, June 2003 Report. Food Market. Inst.-Natl. Counc. Chain Restaurants, Washington, DC.
Frankenhuis, M. T., M. H. Vertommen, and H. Hemminga.1991. Influence of claw clipping, stocking density and feeding space on the incidence of scabby hips in broilers. Br. Poult. Sci.32:227-230.
Frost T J, Ro la nd D A Sr. The influence of various calcium and phosphorus levels on tibia strength and Egg shell quality of pullets during peak production[J]. Poultry Science,1991,70(4):963-969.
Garner, J. P., C. Falcone, P. Wakenell, M. Martin, and J. A. Mench.2002. Reliability and validity of a modified gait scoring system and its use in assessing tibial dyschondroplasia in broilers. Br. Poult. Sci.43:355-363.
Griffin, H.D., and C. C. Whitehead.1982. Plasma lipoprotein concentration as an indicator of fatness in broilers:Development and use of a simple assay for plasma very low density lipoproteins. Br. Poult. Sci.23:307-313.
Hall, A. L.2001. The effect of stocking density on the welfare and behaviour of broiler chickens reared commercially. Anim. Welf.10:23-40.
Harms, R. H., and C. F. Simpson.1977. Influence of wet litter and supplemental biotin on foot pad dermatitis in turkey poults. Poult. Sci.56:2009-2012.
Han, T., E. H. Leone, I. Estevez, and B. D. Humphrey.2005. Effect of group size and housing density on behavior and stress responses in broilers. Poult. Sci.79(Suppl.1):2. (Abstr.)
Hansen, R. S., and W. A. Becker.1960. Feeding space, population density and growth of young chickens. Poult. Sci.39:654-661.
Harrold R L, Slanger W D, Haugse C N, et al. Phosphorus bioavailability in the chick:effects of pro tein source and calcium level[J]. Journal of Animal Science,1983,57(5):1173-1181.
Heckert, R. A., I. Estevez, E. Russek-Cohen, and R. Pettit-Riley.2002. Effects of density and perch availability on the immune status of broilers. Poult. Sci.81:451-457.
Heishman, J. O., C. O. Cunningham, and T. B. Clark.1952. Floor space requirement of broilers. Poult. Sci.31:920.
Hulan, H. W., G De Groote, G Fontaine, G De Munter, K. B. McRae, and F. G Proudfoot.1985. The effect of different totals and ratios of dietary calcium and phosphorus on the performance and incidence of leg abnormalities of male and female broiler chickens. Poultry Science, 64:1157-1169.
Hussein A S, Canto r A H, Jo hnson T H, et al. Relationship of dietary aluminum, phosphorus, and calcium to phosphorus and calcium metabolism and growth performance of broiler chicks[J].
Poultry Science,1990,69(6):966-971.
Jones, T. A., C. A. Donnelly, and M. S. Dawkins.2005. Environmental and management factors affecting the welfare of chickens on commercial farms in the United Kingdom and Denmark stocked at five densities. Poult. Sci.84:1155-1165.
Kamphues, J., I. Youssef, A. Abd El-Wahab, B. Uffing, M. Witte, and M. Tost.2011. Influences of feeding and housing on foot pad health in hens and turkeys. Ubers. Tierernahrg 39:147-193.
Keeling L, Andersson L, Schutz K E, et al. Chicken genomics:feather-pecking and victim pigmentation [J]. Nature,2004,431(7009):645-646.
Kestin, S. C., T. G. Knowles, A. F. Tinch, and N. G Gregory.1992. The prevalence of leg weakness in broiler chickens and its relationship with genotype. Vet. Rec.131:190-194.
Kim, W. K., S. A. Bloomfield, and S. C. Ricke.2011. Effects of age, vitamin D3, and fructooligosaccharides on bone growth and skeletal integrity of broiler chicks. Poult Sci. 90:2425-2432.
Leeson S, Walsh T. Feathering in commercial poultry Ⅰ:Feather growth and composition[J]. World's Poultry Science Journal,2004,60:42-51.
Leeson S, Walsh T. Feathering in commercial poultry II:Factors influencing feather growth and feather loss[J]. World's Poultry Science Journal,2004,60:52-64.
Lewis, N. J., and J. F. Hurnik.1990. Locomotion of broiler chickens in floor pens[J]. Poult. Sci. 69:1087-1093.
Ling B, Ange 1C R, Applega te T J, et al. The nonphytate phosphor us requirements of broile rs in a four- phase feeding program[J]. Poultry Science,2000,79(Suppl.1):11.
Lin, H., E. Decuypere, and J. Buyse.2004a. Oxidative stress induced by corticosterone administration in broiler chickens (Gallus gallus domesticus) 1. Chronic exposure. Comp. Biochem. Physiol. B 139:737-744.
Lin, H., E. Decuypere, and J. Buyse.2004b. Oxidative stress induced by corticosterone administration in broiler chickens (Gallus gallus domesticus) 2. Short-term effect. Comp. Biochem. Physiol. B 139:745-751Malone, G. W., G W. Chaloupka, J. W. Merkley, and L. H. Littlefield.1980. The effects of feeder space and light treatment on broiler performance. Poult. Sci.59:2697-2702.
Lopez, G, K. de Lange, and S. Leeson.2007. Partitioning of retained energy in broilers and birds with intermediate growth rate. Poult. Sci.86:2162-2171.
Martrenchar, A., E. Boilletot, D. Huonnic, and F. Pol.2002. Risk factors for foot-pad dermatitis in chicken and turkey broilers in France. Prev. Vet. Med.52:213-226.
Martrenchar, A., D. Huonnic, J. P. Cotte, E. Boilletot, and J. P. Morisse.2000. Influence of stocking density, artificial dusk and group size on the perching behaviour of broilers. Br. Poult. Sci. 41:125-130.
Meluzzi A., C. Fabbri, E. Folegatti and F. Sirri. Survy of chicken rearing conditions in Italy:effects of litter quality and stocking density on productivity, foot dermatitis and carcase injuries. British Poultry Science,2008a,49(3):257-264.
Mayne, R. K., R. W. Else, and P. M. Hocking.2007. High dietary concentrations of biotin did not prevent foot pad dermatitis in growing turkeys and external scores were poor indicators of histopathological lesions. Br. Poult. Sci.48:291-298.
Nagaraj, M., C. A. P. Wilson, J. B. Hess, and S. F. Bilgili.2007. Effect of high-protein and all-vegetable diets on the incidence and severity of pododermatitis in broiler chickens. J. Appl. Poult. Res.16:304-312.
Nahashon S. N., N. Adefope, A. Amenyenu, J. Tyus Ⅱ, and D. Wright. The effect of floor density on growth performance and carcass characteristics of French guinea broilers. Poultry Science,2009, 88:2461-2467.
National Chicken Council.2005. Animal welfare guidelines and audit checklist. Natl. Chicken Counc., Washington, DC.
Nelson, T. S., L. K. Kirby, and Z. B. Johnson.1992. Effect of calcium, phosphorus, and energy level on the incidence of weak legs in heavy male broilers. J. Appl. Poult. Res.1:11-18.
Newberry, R. C., and J. W. Hall.1990. Use of pen space by broiler-chickens-Effects of age and pen size. Appl. Anim. Behav. Sci.25:125-136.
Newman, S., and S. Leeson.1999. The effect of dietary supplementation with 1,25-dihydroxycholecalciferol or vitamin C on the characteristics of the tibia of older laying hens. Poult. Sci.78:85-90.
Nicol C J. Behavioural responses of laying hens following a period of spatial restriction [J]. Animal Behaviour,1987,35:1709-1719.
Nijdam, E., P. Arens, E. Lambooij, E. Decuypere, and J. A. Stegeman.2004. Factors influencing bruises and mortality of broilers during catching, transport, and lairage. Poult. Sci. 83:1610-1615.
NRC.1994. Nutrient Requirements of Poultry.9th rev. ed. National Academy Press, Washington, DC.
Oloyo R. A. Responses of broilers fed guineacorn/palm kernel meal based ration to supplemental biotin. Journal of the Science of Food and Agricalture,1991,55(4):539-550.
Onyango E M, Hester P Y, Stroshine R, et al. Bone densit ometry as an indicator of percentage tibia ash in broiler chicks fed varying dietary calcium and phosphorus levels [J]. Poultry Science,2003, 82(11):1787-1791.
Pettit-Riley, R., and I. Estevez.2001. Effects of density on perching behavior of broiler chickens. Appl. Anim. Behav. Sci.71:127-140.
Peyenet, J., and J. C. Pouillot.1972. Etude critique d'une dosage du phosphorus sans deproteinsation, in:Organisation des laboratories, Biologie propective, p.57, Paris, L, Expansion Scientifique Francaise.
Post J, Rebel J M, Huurne A A H. Physiological effects of elevated plasma corticosterone concentration in broiler chickens. An alternative means by which to assess the physiological effects of stress[J]. Poultry Science,2003,82:1313-1318.
Powell S, Johnston S, Gaston L, et al. The effect of dietary phosphorus level and phytase supplem entation on growth performance, bone-breaking strength, and litter phosphorus c oncentration in broilers[J]. Poultry Science,2008,87 (5):949-957.
Proudfoot, F. G., H. W. Hulan, and D. R. Ramey.1979. Effect of 4 stocking densities on broiler carcass grade, the incidence of breast blisters, and other performance traits. Poult. Sci. 58:791-793.
Puron, D., R. Santamaria, J. C. Segura, and J. L. Alamilla.1995. Broiler performance at different stocking densities. J. Appl. Poult. Res.4:55-60.
Puvadolpirod, S., and J. P. Thaxton.2000a. Model of physiological stress in chickens.1. Response parameters. Poult. Sci.79:363-369.
Randolph D. Mitchell, J. R. Hardy M. Edwards, Gayner R. Mcdaniel, and George N. Rowland.1997. Dietary 1,25-dihydroxycholecalciferol has variable effects on the incidences of leg abnormalities, plasma vitamin D metabolites, and vitamin D receptors in chickens divergently selected for tibial dyschondroplasia. Poult. Sci.76:338-345.
Ray Sarkar, B. C., and U. P. S. Chauhan.1967. A new method for determining micro quantities of calcium in biological materials. Analytical Biochemistry,20:155-166.
Remmenga, D. M., G. A. Milliken, and D. Kratzer.1997. Estimating the maximum effectivedose in a quantitative dose-response experiment. J Anim Sci.75:2174-2183.
Royal Society for the Prevention of Cruelty to Animals.2002. Welfare standards for chickens. R. Soc. Prev. Cruelty Anim., West Sussex, UK.
Sanotra, G. S., L. G. Lawson, and K. S. Vestergaard.2001a. Influence of stocking density on tonic immobility, lameness, and tibial dyschondroplasia in broilers. J. Appl. Anim. Welf. Sci.4:71-87.
Sanotra, G S., J. D. Lund, A. K. Ersboll, J. S. Petersen, and K. S. Vestergaard.2001b. Monitoring leg problems in broilers:Asurvey of commercial broiler production in Denmark. World Poult. Sci. J. 57:55-69.
Sanotra, G. S., J. D. Lund, and K. S. Vestergaard.2002. Influence of light-dark schedules and stocking density on behaviour, risk of leg problems and occurrence of chronic fear in broilers.Br. Poult. Sci.43:344-354.
Scientific Committee on Animal Health and Welfare.2000. The Welfare of Chickens Kept for Meat Production(Broilers). European Commission, Health and Consumer Protection Directorate-General, Brussels, Belgium.
Sebastian S, Touchburn S P, Chavez E R, et al. Efficacy of supplemental microbial phytase at different dietary calcium levels on growth performance and mineral utilization of broiler chickens[J]. Poultry Sc ience,1996,75(12):1516-1523.
Shafey, T. M., and M. W. McDonald.1991. The effects of dietary calcium, phosphorus, and protein on the performance and nutrient utilization of broiler chickens. Poult Sci.70(3):548-553.
Shanawany, M. M.1988. Broiler performance under high stocking densities. Br. Poult. Sci.29:43-52. Shepherd, E. M., and B. D. Fairchild.2010. Footpad dermatitis in poultry. Poult. Sci. 89:2043-2051.
Shirley, R. B., A. J. Davis, M. M. Compton, and W. D. Berry.2003. The expression of calbindin in chicks that are divergently selected for low or high incidence of tibial dyschondroplasia. Poult. Sci.82:1965-1973.
Skinner, J. T., M. H. Adams, S. E. Watkins, and P. W. Waldroup.1992. Effects of calcium and nonphytate phosphorus levels fed during 42 to 56 days of age on performance and bone strength of male broilers. J. Appl. Poult. Res,1:167-171.
S(?)rensen, P., G Su, and S. C. Kestin.2000. Effects of age and stocking density on leg weakness in broiler chickens. Poult. Sci.79:864-870.
Tablante, N. L., I. Estevez, and E. Russek-Cohen.2003. Effect of perches and stocking density on tibial dyschondroplasia and bone mineralization as measured by bone ash in broiler chickens. J. Appl. Poultry Res.12:53-59.
Thaxton, J. P., W. A. Dozier, S. L. Branton, G W. Morgan, D. W. Miles, W. B. Roush, B. D. Lott, and Y. Vizzier-Thaxton.2006. Stocking density and physiological adaptive responses of broilers. Poult. Sci.85:819-824.
Tomhave, A. E., and K. C. Seeger.1945. Floor space requirements of broilers. Delaware Agric. Exp. Sta. Bull.255.
Villagra, A., J. L. Ruiz de la Torre, G Chacon, M. Lainez, A. Torres, and X. Manteca.2009. Stocking density and stress induction affect production and stress parameters in broiler chickens. Anim. Welf.18:189-197.
Vits A, Weitzenburger D, Hamann H, et al. Production, Egg Quality, Bone Strength, Claw Length, and Keel Bone Deformities of Laying Hens Housed in Furnished Cages with Different Group Sizes[J]. Poultry Science,2005,84:1511-1519.
Waldroup, P. W., R. J. Mitchell, and K. R. Hazen.1974. The phosphorus needs of finishing broilers in relationship to dietary nutrient density levels.Poult.Sci.53:1655-1663.
Wang, G, C. Ekstrand, and J. Svedberg.1998. Wet litter and perches as risk factors for the development of foot pad dermatitis in floor-housed hens. Br. Poult. Sci.39:191-197.
Wang, X. J., H. Lin, Z. G Song, H. C. Jiao.2010. Dexamethasone facilitates lipid accumulation and mild feed restriction improves fatty acids oxidation in skeletal muscle of broiler chicks (Gallus gallus domesticus). Comp. Biochem. Physiol. C 151:447-454.
Watkins B. A., S. D. Bain, J. W. Newbrey. Eicosanoic fatty acid reduction in the tibiotarsus of biotin-deficient chicks. Calcified Tissue International,1989,45(1):41-46.
Watson, B. C., J. O. Matthews, L. L. Southern, and J. L. Shelton.2006. The effects of phytase on growth performance and intestinal transit time of broilers fed nutritionally adequate diets and diets deficient in calcium and phosphorus. Poultry Science.85:493-497.
Weaver, W. D., and R. Meijerhof.1991. The effect of different levels of relative-humidity and air movement on litter conditions, ammonia levels, growth, and carcass quality for broiler-chickens. Poult. Sci.70:746-755.
Weeks, C. A., C. J. Nicol, C. M. Sherwin, and S. C. Kestin.1994. Comparison of the behaviour of broiler chickens in indoor and free-range environments. Anim. Welf.3:179-192.
Weeks, C. A., T. D. Danbury, H. C. Davies, P. Hunt, and S. C. Kestin.2000. The behaviour of broiler chickens and its modification by lameness. Appl. Anim. Behav. Sci.67:111-125.
Whitehead, C. C.1977. The use of biotin in poultry nutrition. World's Poult. Sci. J.33:140-154.
Whitehead, C. C.1988. Biotin in Animal Nutrition. F. Hoffmann-La Roche & Co. Ltd., Basel, Switzerland.
Wong-Valle, J., G R. Mcdaniel, D. L. Kuhlers, and J. E. Bartels.1993. Correlated responses to selection for high or low incidence of tibial dyschondroplasia in broilers. Poult. Sci. 72:1621-1629.
Yan F, Angel R, Ashwell C, et al. Evaluation of the broiler stability to adapt to an early moderate def-iciency of phosphorus and calcium[J]. Poultry Science,2005,84(8):1232-1241.
Youssef, I. M. I., A. Beineke, K. Rohn, and J. Kamphues.2011. Effects of high dietary levels of soybean meal and its constituents (potassium, oligosaccharides) on foot pad dermatitis in growing turkeys housed on dry and wet litter. Arch. Anim. Nutr.65:148-162.
Youssef, I. M. I., A. Beineke, K. Rohn, and J. Kamphues.2012. Influences of increased levels of biotin, zinc or mannanoligosaccharides in the diet on foot pad dermatitis in growing turkeys housed on dry and wet litter. J. Anim. Physiol. Anim. Nutr. (Berl.) 96:747-761.
Yuan, L., H. Lin, K. J. Jiang, H. C. Jiao, and Z. G Song.2008. Corticosterone administration and high-energy feed results in enhanced fat accumulation and insulin resistance in broiler chickens. Br. Poult. Sci.49:487-495.
Zhang, X., G. R. Mcdaniel, Z. S. Yalcin, and D. L. Kuhlers.1995. Genetic correlations of tibial dyschondroplasia incidence with carcass traits in broilers. Poult. Sci.74:910-915.
Zulkifli I, Liew P K, Israf D A, et al. Effect of early age feed restriction and heat conditioning on heterophil/lymphocyte ratios, heat shock protein 70 expression and body temperature of heat stressed broiler chickens[J]. Thermal Biology,2003,28:217-222.
初晓娜,汪以真,刘光富,朱连勤.高磷饲粮对肉仔鸡体组织钙、磷、镁含量的影响.中国饲料,2004,8：15-18.
丁角立,孙启军,朱玉琴,周毓平.饲粮中钙磷水平对肉用仔鸡生长性能及机体钙磷含量的影响.中国畜牧杂志,1994,5：6-9.
冯永淼,闫素梅,张海琴,史彬林,曹平.维生素A、D及其相互作用对肉仔鸡生长性能及组织维生素A、E浓度的影响.动物营养学报,2007,19(4)：411-416.
耿爱莲.规模饲养环境条件对肉鸡健康、福利以及鸡肉品质的影响.中国家禽,2007,(04).
呙于明,周毓平,丁角立.饲粮赖氨酸、蛋氨酸水平对肉鸡胴体组成的影响.动物营养学报,1989,1(1)：35-40.
呙于明,邵宪萍,丁角立,朱玉琴,周毓平.生长后期饲粮钙磷水平对肉仔鸡生长性能及胫骨矿化度的影响.中国饲料,1995,13：10-11.
龚月生,王志有,姚清东.赖氨酸水平和性别对肉仔鸡胴体品质的影响.动物营养学报,1993,5(1)：63-69.
韩春芳,蔡辉益,于会民,曹社会.不同生物素添加水平对肉仔鸡免疫器官发育和免疫功能的影响.西北农林科技大学学报(自然科学版),2005,33(11)：61-66.
丁角立,孙启军,朱玉琴,等.饲粮中钙磷水平对肉用仔鸡生产性能及机体钙磷含量的影响[J]中国畜牧杂志,1994,30(5)：6-9.
李健,侯水生,黄俊纯.肉仔鸡生物素缺乏症的观测及生物素需要量的探讨.畜牧兽医学报,1994,25(4)：295-300.
林勇,徐忠宝.饲料钙磷比对肉用仔鸡体内钙磷比影响的研究.畜牧与兽医,1997,29(3)：114.
刘光富,汪以真,朱连勤,初晓娜.2003.饲喂高磷饲粮对肉仔鸡机体组织钙、磷含量的影响.饲料博览,8：16-18.
卢菁,冯定远,邓跃林.饲粮磷水平对肉用小鸡生长性能的影响.广东饲料,2000,9：15-16.
马现永,蒋宗勇,林映才,周桂莲,张罕星.钙和维生素D3对黄羽肉鸡肌肉嫩度的影响及机理.动物营养学报,2009,21(3)：356-362.
石天虹,张桂芝,黄保华,刘雪兰,井庆川,武彬,魏祥法,刘瑞亭,闫佩佩.低能低蛋白条件下饲粮维生素D3对0-6周龄肉仔鸡影响的研究.家禽科学,2010,12：9-13.
赵宇,施正香,赵芙蓉,周东,董泰丽,隋锡兰.音乐及饲养密度对肉杂鸡生产及屠宰性能影响初探.农业工程学报,2006,22：155-158.
周林.生物素和维生素E对肉鸡屠宰性能和肉品质的影响.饲料博览,2000,8：6-7.
张海琴.维生素A、D对肉鸡生长、免疫、钙磷代谢的影响及其交互作用的研究.硕士学位论文.呼和浩特：内蒙古农业大学.2006.
张征.饲粮钙过量对雏鸡的影响.畜禽与禽病防疫,1996,7：34.
仲明,郑家佐.产蛋高峰期饲粮中钙磷水平对产蛋鸡胫骨强度及产蛋性能的影响[J].新疆畜牧业,2000,3：15-17.
朱连勤,朱风华,王清吉,张宗敏,巩青军,谭翠英,王善淑..低磷饲粮对产蛋鸡生长性能及脏器组织磷含量的影响.中国家禽,2000,9：7-10.
Abd El-Wahab, A., C. F. Visscher, A. Beineke, M. Beyerbach, and J. Kamphues.2011. Effects of floor heating and litter quality on the development and severity of foot pad dermatitis in young turkeys. Avian Dis.55:429-434.
Abd El-Wahab, A., C. F. Visscher, A. Beineke, M. Beyerbach, and J. Kamphues.2013a. Effects of high electrolyte contents in the diet and using floor heating on development and severity of foot pad dermatitis in young turkeys. J. Anim. Physiol. Anim. Nutr.97:39-47.
Abd El-Wahab, A., C. F. Visscher, S. Wolken, J.-M. Reperant, A. Beineke, M. Beyerbach, and J. Kamphues.2013b. Outcome of an artificial coccidial infection in poults under the influence of floor heating. Poult. Sci.92:629-637.
Abd El-Wahab, A., C. F. Visscher, S. Wolken, J.-M. Reperant, A. Beineke, M. Beyerbach, and J. Kamphues.2012. Foot pad dermatitis and experimentally induced coccidiosis in young turkeys fed a diet without anticoccidia. Poult. Sci.91:627-635.
Abd El-Wahab, A., D. Radko, and J. Kamphues.2013c. High dietary levels of biotin and zinc to improve health of foot pads in broilers exposed experimentally to litter with critical moisture content. Poult. Sci.92:1774-1782.
Andrews, S. M., H. M. Omed, and C. J. C. Phillips.1997. The effect of a single or repeated period of high stocking densityon the behavior and response to stimuli in broiler chickens. Poult. Sci. 76:1655-1660.
Angel, R., T. J. Applegate, and M. Christman.2000. Effects of dietary nonphytate phosphorus on performance and bone measurements in broilers fed on a four phase feeding system. Poult. Sci. 79(Suppl.1):21-22.
AOAC,1996. Moisture in Animal Feed. Method 930.15 in Official Methods of Analysis of AOAC International.16th ed. AOAC International, Gaithersburg, MD.
Arnould, U., and J. M. Faure.2003. Use of pen space and activity of broiler chickens reared at two different densities. Appl. Anim. Behav. Sci.84:281-296.
Atencio, A., H. M. Edwards Jr., G M. Pesti, and G. O. Ware.2006. The vitamin D3 requirement of broiler breeders. Poult. Sci.85:674-692.
Atencio A, Edw ards H M Jr, Pesti G M. Effect of the leve l o f cho leca lcifer olsupplementation of broiler breeder hen diets on the performance and bone abnorma lities of the progeny fed diets containing various levels of calcium or 25-hydroxy cholecalciferol[J]. Poultry Science,2005, 84(10):1593-1603.
Atteh J O, Leeson S. Influence of increasing the calium and magnesium content of the drinking water on performance and bone and plasma minerals of broiler chickens[J]. Poultry Science,1983, 62(5):869-874.
Bain S. D., J. W. Newbrey, B. A. Watkins. Biotin deficiency may alter tibiotarsal bone growth and modeling in broiler chicks. Poultry Science,1988,67(4):590-595.
Beloor, J., H. K. Kang, Y. J. Kim, V. K. Subramani, I. S. Jang, and S. H. Sohn. The effect of stocking density on stress related genes and telomeric length in broiler chickens. Asian-Aus. J. Anim. Sci.2010,23:437-443.
Berg, C. C.1998. Foot-pad dermatitis in broilers and turkeys-Prevalence, risk factors and prevention. PhD Diss. Swedish Univ. Agric. Sci., Skara.
Biehl, R. R., and D. H. Baker.1997. Utilization of phytate and nonphytate phosphorus in chicks as affected by source and amount of vitamin D3. J. Anim. Sci.75:2986-2993.
Bilgili, S. F., and J. B. Hess.1995. Placement density influences broiler carcass grade and meat yields. J. Appl. Poult. Res.4:384-389.
Bilgili, S. F., M. A. Alley, J. B. Hess, and M. Nagaraj.2006. Influence of age and sex on footpad quality and yield in broiler chickens reared on low and high density diets. J. Appl. Poult. Sci. 15:433-441
Bilgili, S. F.2009. Factors contributing to foot pad dermatitis in broilers. Watt Poultry USA, pp. 26-27.
Bolton W., W. A. Dewar, R. Morley Jones and R. Thompson. Effect of stocking density on performance of broiler chicks. British Poultry Science,1972,13:157-162.
Bolton, W., R. Thompson, R. M. Jones, and W. A. Dewar.1972. Effect of stocking density on performance of broiler chicks. Br. Poult. Sci.13:157-162.1. Chen X, and E. T. Moran.1995. The withdrawal feed of broilers:Carcass responses to dietary phosphorus. J. Appl. Poult. Res. 4:69-82.
Broz J, Olda le P, Perr in Vo ltz A H, et al. Effects of supplemental phytase on performance and pho sphorus utilisation in broiler chickens fed a low phosphorus diet without addition of inorganic pho sphates[J]. British Poultry Science,1994,35(3):273-280.
Buda, S.2000. Effects of biotin on the skin of turkey foot pads. World Poult.16:47-48.
Collins, L. M., and D. J. T. Sumpter.2007. The feeding dynamics of broiler chickens. J. R. Soc. Interface 4:65-72.
Cornetto, T. L., and I. Estevez.2001. Behavior of the domestic fowl in presence of vertical panels. Poult. Sci.80:1455-1462.
Cornetto, T., I. Estevez, and L. W. Douglass.2002. Using artificial cover to reduce aggression and disturbances in domestic fowl. Appl. Anim. Behav. Sci.75:325-336.
Cravener, T. L., W. B. Roush, and M. M. Mashaly.1992. Broiler production under varying population-densities. Poult. Sci.71:427-433.
Dawkins, M. S., C. A. Donnelly, and T. A. Jones.2004. Chicken welfare is influenced more by housing conditions than by stocking density. Nature 427:342-344.
Dawkins M S, Hardie S. Space needs of laying hens [J].British Poultry Science,1989,30:413-416.
Deaton, J. W., F. N. Reece, and T. H. Vardaman.1968. Effect of temperature and density on broiler performance. Poult. Sci.47:293-300.
Dhandu A S, Angel R. Broiler nonphytin phosphorus requirement in the finisher and withdrawal phases of acommercia I four-phase feeding system[J].Poultry Science,2003,82(8):1257-1265.
Dozier, W. A., B. D. Lott, and S. L. Branton.2005a. Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point. Poult. Sci. 84:1328-1331.
Dozier, W. A., J. P. Thaxton, S. L. Branton, G. W. Morgan, D. M. Miles, W. B. Roush, B. D. Lott, and Y. Vizzier-Thaxton.2005b. Stocking density effects on growth performance and processing yields of heavy broilers. Poult. Sci.84:1332-1338.
Dozier, W. A., J. P. Thaxton, J. L. Purswell, H. A. Olanrewaju, S. L. Branton, and W. B. Roush.2006. Stocking density effects on male broilers grown to 1.8 kilograms of BW. Poult. Sci.85:344-351.
Driver, J. P., A. Atencio, G. M. Pesti, H. M. Edwards, Jr., and R. I Bakalli.2006. The effect of maternal dietary vitamin D3 supplementation on performance and tibial dyschondroplasia of broiler chicks. Poult. Sci.85:39-47.
Driver, J. P., G. M. Pesti, R. I. Bakalli, and H. M. Edwards Jr.2005. Phytase and 1α-hydroxycholecalciferol supplementation of broiler chickens during the starting and growing/finishing phases. PouIt.Sci.84:1616-1628. Dawkins, M. S., C. A. Donnelly, and T. A. Jones.2004. Chicken welfare is influenced more by housing conditions than by stocking density. Nature 427:342-344.
Edwards, H. M., R. B. Shirley, A. Atencio, and G. M. Pesti.2004. Effect of dietary Ca levels on the efficacy of 1-α-hydroxycholecalciferol in the diets of young broilers. in World's Poult. Congr. Exhib. Istanbul, Turkey:494.
Edwards, H. M., Jr.2002. Studies on the Efficacy of cholecalciferol and derivatives for stimulating phytate utilization in broilers. Poult. Sci.81:1026-1031.
Ekstrand, C.1993. Effects of stocking density on the health, behaviour and productivity of broilers, a literature review. Swedish Univ. Agric. Sci., Skara.
Ekstrand, C., B. Algers, and J. Svedberg.1997. Rearing conditions and foot-pad dermatitis in Swedish broiler chickens. Prev. Vet. Med.31:167-174.
Ekstrand, C., and T. E. Carpenter.1998. Temporal aspects of foot-pad dermatitis in Swedish broilers. Acta Vet. Scand.39:229-236.
Elfadil, A. A., J. P. Vaillancourt, and A. H. Meek.1996. Impact of stocking density, breed, and feathering on the prevalence of abdominal skin scratches in broiler chickens. Avian Dis. 40:546-552.
Estevez, I.1994. Efecto del tamano de grupo y de las condiciones de manejo en el comportamiento y uso del espacio del gallo dome'stico (Gallus gallus). PhD Diss. Univ. Co'rdoba, Spain.
Estevez, I.1999. Density:How it can affect the behavior and health of your birds. Fact Sheet,758, Maryland Coop. Ext., Univ. Maryland.
Estevez, I., R. C. Newberry, and L. Arias de Reyna.1997. Broiler chickens:A tolerant social system Etologia 5:19-29.
Estevez, I.2007. Density allowances for broilers:where to set the limits. Poult.Sci.86:1265-1272.
Febrer, K., T. A. Jones, C. A. Donnelly, and M. S. Dawkins.2006. Forced to crowd or choosing to cluster Spatial distribution indicates social attraction in broiler chickens. Anim. Behav. 72:1291-1300.
Feddes, J. J. R., E. J. Emmanuel, and M. J. Zuidhof.2002. Broiler performance, BW variance, feed and water intake, and carcass quality at different stocking densities. Poult. Sci.81:774-779.
Food Market Institute-National Council of Chain Restaurants.2003. FMI-NCCR Animal welfare program, June 2003 Report. Food Market. Inst.-Natl. Counc. Chain Restaurants, Washington, DC.
Frankenhuis, M. T., M. H. Vertommen, and H. Hemminga.1991. Influence of claw clipping, stocking density and feeding space on the incidence of scabby hips in broilers. Br. Poult. Sci.32:227-230.
Frost T J, Ro la nd D A Sr. The influence of various calcium and phosphorus levels on tibia strength and Egg shell quality of pullets during peak production[J]. Poultry Science,1991,70(4):963-969.
Garner, J. P., C. Falcone, P. Wakenell, M. Martin, and J. A. Mench.2002. Reliability and validity of a modified gait scoring system and its use in assessing tibial dyschondroplasia in broilers. Br. Poult. Sci.43:355-363.
Griffin, H.D., and C. C. Whitehead.1982. Plasma lipoprotein concentration as an indicator of fatness in broilers:Development and use of a simple assay for plasma very low density lipoproteins. Br. Poult. Sci.23:307-313.
Hall, A. L.2001. The effect of stocking density on the welfare and behaviour of broiler chickens reared commercially. Anim. Welf.10:23-40.
Harms, R. H., and C. F. Simpson.1977. Influence of wet litter and supplemental biotin on foot pad dermatitis in turkey poults. Poult. Sci.56:2009-2012.
Han, T., E. H. Leone, I. Estevez, and B. D. Humphrey.2005. Effect of group size and housing density on behavior and stress responses in broilers. Poult. Sci.79(Suppl.1):2. (Abstr.)
Hansen, R. S., and W. A. Becker.1960. Feeding space, population density and growth of young chickens. Poult. Sci.39:654-661.
Harrold R L, Slanger W D, Haugse C N, et al. Phosphorus bioavailability in the chick:effects of pro tein source and calcium level[J]. Journal of Animal Science,1983,57(5):1173-1181.
Heckert, R. A., I. Estevez, E. Russek-Cohen, and R. Pettit-Riley.2002. Effects of density and perch availability on the immune status of broilers. Poult. Sci.81:451-457.
Heishman, J. O., C. O. Cunningham, and T. B. Clark.1952. Floor space requirement of broilers. Poult. Sci.31:920.
Hulan, H. W., G De Groote, G Fontaine, G De Munter, K. B. McRae, and F. G Proudfoot.1985. The effect of different totals and ratios of dietary calcium and phosphorus on the performance and incidence of leg abnormalities of male and female broiler chickens. Poultry Science, 64:1157-1169.
Hussein A S, Canto r A H, Jo hnson T H, et al. Relationship of dietary aluminum, phosphorus, and calcium to phosphorus and calcium metabolism and growth performance of broiler chicks[J].
Poultry Science,1990,69(6):966-971.
Jones, T. A., C. A. Donnelly, and M. S. Dawkins.2005. Environmental and management factors affecting the welfare of chickens on commercial farms in the United Kingdom and Denmark stocked at five densities. Poult. Sci.84:1155-1165.
Kamphues, J., I. Youssef, A. Abd El-Wahab, B. Uffing, M. Witte, and M. Tost.2011. Influences of feeding and housing on foot pad health in hens and turkeys. Ubers. Tierernahrg 39:147-193.
Keeling L, Andersson L, Schutz K E, et al. Chicken genomics:feather-pecking and victim pigmentation [J]. Nature,2004,431(7009):645-646.
Kestin, S. C., T. G. Knowles, A. F. Tinch, and N. G Gregory.1992. The prevalence of leg weakness in broiler chickens and its relationship with genotype. Vet. Rec.131:190-194.
Kim, W. K., S. A. Bloomfield, and S. C. Ricke.2011. Effects of age, vitamin D3, and fructooligosaccharides on bone growth and skeletal integrity of broiler chicks. Poult Sci. 90:2425-2432.
Leeson S, Walsh T. Feathering in commercial poultry Ⅰ:Feather growth and composition[J]. World's Poultry Science Journal,2004,60:42-51.
Leeson S, Walsh T. Feathering in commercial poultry II:Factors influencing feather growth and feather loss[J]. World's Poultry Science Journal,2004,60:52-64.
Lewis, N. J., and J. F. Hurnik.1990. Locomotion of broiler chickens in floor pens[J]. Poult. Sci. 69:1087-1093.
Ling B, Ange 1C R, Applega te T J, et al. The nonphytate phosphor us requirements of broile rs in a four- phase feeding program[J]. Poultry Science,2000,79(Suppl.1):11.
Lin, H., E. Decuypere, and J. Buyse.2004a. Oxidative stress induced by corticosterone administration in broiler chickens (Gallus gallus domesticus) 1. Chronic exposure. Comp. Biochem. Physiol. B 139:737-744.
Lin, H., E. Decuypere, and J. Buyse.2004b. Oxidative stress induced by corticosterone administration in broiler chickens (Gallus gallus domesticus) 2. Short-term effect. Comp. Biochem. Physiol. B 139:745-751Malone, G. W., G W. Chaloupka, J. W. Merkley, and L. H. Littlefield.1980. The effects of feeder space and light treatment on broiler performance. Poult. Sci.59:2697-2702.
Lopez, G, K. de Lange, and S. Leeson.2007. Partitioning of retained energy in broilers and birds with intermediate growth rate. Poult. Sci.86:2162-2171.
Martrenchar, A., E. Boilletot, D. Huonnic, and F. Pol.2002. Risk factors for foot-pad dermatitis in chicken and turkey broilers in France. Prev. Vet. Med.52:213-226.
Martrenchar, A., D. Huonnic, J. P. Cotte, E. Boilletot, and J. P. Morisse.2000. Influence of stocking density, artificial dusk and group size on the perching behaviour of broilers. Br. Poult. Sci. 41:125-130.
Meluzzi A., C. Fabbri, E. Folegatti and F. Sirri. Survy of chicken rearing conditions in Italy:effects of litter quality and stocking density on productivity, foot dermatitis and carcase injuries. British Poultry Science,2008a,49(3):257-264.
Mayne, R. K., R. W. Else, and P. M. Hocking.2007. High dietary concentrations of biotin did not prevent foot pad dermatitis in growing turkeys and external scores were poor indicators of histopathological lesions. Br. Poult. Sci.48:291-298.
Nagaraj, M., C. A. P. Wilson, J. B. Hess, and S. F. Bilgili.2007. Effect of high-protein and all-vegetable diets on the incidence and severity of pododermatitis in broiler chickens. J. Appl. Poult. Res.16:304-312.
Nahashon S. N., N. Adefope, A. Amenyenu, J. Tyus Ⅱ, and D. Wright. The effect of floor density on growth performance and carcass characteristics of French guinea broilers. Poultry Science,2009, 88:2461-2467.
National Chicken Council.2005. Animal welfare guidelines and audit checklist. Natl. Chicken Counc., Washington, DC.
Nelson, T. S., L. K. Kirby, and Z. B. Johnson.1992. Effect of calcium, phosphorus, and energy level on the incidence of weak legs in heavy male broilers. J. Appl. Poult. Res.1:11-18.
Newberry, R. C., and J. W. Hall.1990. Use of pen space by broiler-chickens-Effects of age and pen size. Appl. Anim. Behav. Sci.25:125-136.
Newman, S., and S. Leeson.1999. The effect of dietary supplementation with 1,25-dihydroxycholecalciferol or vitamin C on the characteristics of the tibia of older laying hens. Poult. Sci.78:85-90.
Nicol C J. Behavioural responses of laying hens following a period of spatial restriction [J]. Animal Behaviour,1987,35:1709-1719.
Nijdam, E., P. Arens, E. Lambooij, E. Decuypere, and J. A. Stegeman.2004. Factors influencing bruises and mortality of broilers during catching, transport, and lairage. Poult. Sci. 83:1610-1615.
NRC.1994. Nutrient Requirements of Poultry.9th rev. ed. National Academy Press, Washington, DC.
Oloyo R. A. Responses of broilers fed guineacorn/palm kernel meal based ration to supplemental biotin. Journal of the Science of Food and Agricalture,1991,55(4):539-550.
Onyango E M, Hester P Y, Stroshine R, et al. Bone densit ometry as an indicator of percentage tibia ash in broiler chicks fed varying dietary calcium and phosphorus levels [J]. Poultry Science,2003, 82(11):1787-1791.
Pettit-Riley, R., and I. Estevez.2001. Effects of density on perching behavior of broiler chickens. Appl. Anim. Behav. Sci.71:127-140.
Peyenet, J., and J. C. Pouillot.1972. Etude critique d'une dosage du phosphorus sans deproteinsation, in:Organisation des laboratories, Biologie propective, p.57, Paris, L, Expansion Scientifique Francaise.
Post J, Rebel J M, Huurne A A H. Physiological effects of elevated plasma corticosterone concentration in broiler chickens. An alternative means by which to assess the physiological effects of stress[J]. Poultry Science,2003,82:1313-1318.
Powell S, Johnston S, Gaston L, et al. The effect of dietary phosphorus level and phytase supplem entation on growth performance, bone-breaking strength, and litter phosphorus c oncentration in broilers[J]. Poultry Science,2008,87 (5):949-957.
Proudfoot, F. G., H. W. Hulan, and D. R. Ramey.1979. Effect of 4 stocking densities on broiler carcass grade, the incidence of breast blisters, and other performance traits. Poult. Sci. 58:791-793.
Puron, D., R. Santamaria, J. C. Segura, and J. L. Alamilla.1995. Broiler performance at different stocking densities. J. Appl. Poult. Res.4:55-60.
Puvadolpirod, S., and J. P. Thaxton.2000a. Model of physiological stress in chickens.1. Response parameters. Poult. Sci.79:363-369.
Randolph D. Mitchell, J. R. Hardy M. Edwards, Gayner R. Mcdaniel, and George N. Rowland.1997. Dietary 1,25-dihydroxycholecalciferol has variable effects on the incidences of leg abnormalities, plasma vitamin D metabolites, and vitamin D receptors in chickens divergently selected for tibial dyschondroplasia. Poult. Sci.76:338-345.
Ray Sarkar, B. C., and U. P. S. Chauhan.1967. A new method for determining micro quantities of calcium in biological materials. Analytical Biochemistry,20:155-166.
Remmenga, D. M., G. A. Milliken, and D. Kratzer.1997. Estimating the maximum effectivedose in a quantitative dose-response experiment. J Anim Sci.75:2174-2183.
Royal Society for the Prevention of Cruelty to Animals.2002. Welfare standards for chickens. R. Soc. Prev. Cruelty Anim., West Sussex, UK.
Sanotra, G. S., L. G. Lawson, and K. S. Vestergaard.2001a. Influence of stocking density on tonic immobility, lameness, and tibial dyschondroplasia in broilers. J. Appl. Anim. Welf. Sci.4:71-87.
Sanotra, G S., J. D. Lund, A. K. Ersboll, J. S. Petersen, and K. S. Vestergaard.2001b. Monitoring leg problems in broilers:Asurvey of commercial broiler production in Denmark. World Poult. Sci. J. 57:55-69.
Sanotra, G. S., J. D. Lund, and K. S. Vestergaard.2002. Influence of light-dark schedules and stocking density on behaviour, risk of leg problems and occurrence of chronic fear in broilers.Br. Poult. Sci.43:344-354.
Scientific Committee on Animal Health and Welfare.2000. The Welfare of Chickens Kept for Meat Production(Broilers). European Commission, Health and Consumer Protection Directorate-General, Brussels, Belgium.
Sebastian S, Touchburn S P, Chavez E R, et al. Efficacy of supplemental microbial phytase at different dietary calcium levels on growth performance and mineral utilization of broiler chickens[J]. Poultry Sc ience,1996,75(12):1516-1523.
Shafey, T. M., and M. W. McDonald.1991. The effects of dietary calcium, phosphorus, and protein on the performance and nutrient utilization of broiler chickens. Poult Sci.70(3):548-553.
Shanawany, M. M.1988. Broiler performance under high stocking densities. Br. Poult. Sci.29:43-52. Shepherd, E. M., and B. D. Fairchild.2010. Footpad dermatitis in poultry. Poult. Sci. 89:2043-2051.
Shirley, R. B., A. J. Davis, M. M. Compton, and W. D. Berry.2003. The expression of calbindin in chicks that are divergently selected for low or high incidence of tibial dyschondroplasia. Poult. Sci.82:1965-1973.
Skinner, J. T., M. H. Adams, S. E. Watkins, and P. W. Waldroup.1992. Effects of calcium and nonphytate phosphorus levels fed during 42 to 56 days of age on performance and bone strength of male broilers. J. Appl. Poult. Res,1:167-171.
S(?)rensen, P., G Su, and S. C. Kestin.2000. Effects of age and stocking density on leg weakness in broiler chickens. Poult. Sci.79:864-870.
Tablante, N. L., I. Estevez, and E. Russek-Cohen.2003. Effect of perches and stocking density on tibial dyschondroplasia and bone mineralization as measured by bone ash in broiler chickens. J. Appl. Poultry Res.12:53-59.
Thaxton, J. P., W. A. Dozier, S. L. Branton, G W. Morgan, D. W. Miles, W. B. Roush, B. D. Lott, and Y. Vizzier-Thaxton.2006. Stocking density and physiological adaptive responses of broilers. Poult. Sci.85:819-824.
Tomhave, A. E., and K. C. Seeger.1945. Floor space requirements of broilers. Delaware Agric. Exp. Sta. Bull.255.
Villagra, A., J. L. Ruiz de la Torre, G Chacon, M. Lainez, A. Torres, and X. Manteca.2009. Stocking density and stress induction affect production and stress parameters in broiler chickens. Anim. Welf.18:189-197.
Vits A, Weitzenburger D, Hamann H, et al. Production, Egg Quality, Bone Strength, Claw Length, and Keel Bone Deformities of Laying Hens Housed in Furnished Cages with Different Group Sizes[J]. Poultry Science,2005,84:1511-1519.
Waldroup, P. W., R. J. Mitchell, and K. R. Hazen.1974. The phosphorus needs of finishing broilers in relationship to dietary nutrient density levels.Poult.Sci.53:1655-1663.
Wang, G, C. Ekstrand, and J. Svedberg.1998. Wet litter and perches as risk factors for the development of foot pad dermatitis in floor-housed hens. Br. Poult. Sci.39:191-197.
Wang, X. J., H. Lin, Z. G Song, H. C. Jiao.2010. Dexamethasone facilitates lipid accumulation and mild feed restriction improves fatty acids oxidation in skeletal muscle of broiler chicks (Gallus gallus domesticus). Comp. Biochem. Physiol. C 151:447-454.
Watkins B. A., S. D. Bain, J. W. Newbrey. Eicosanoic fatty acid reduction in the tibiotarsus of biotin-deficient chicks. Calcified Tissue International,1989,45(1):41-46.
Watson, B. C., J. O. Matthews, L. L. Southern, and J. L. Shelton.2006. The effects of phytase on growth performance and intestinal transit time of broilers fed nutritionally adequate diets and diets deficient in calcium and phosphorus. Poultry Science.85:493-497.
Weaver, W. D., and R. Meijerhof.1991. The effect of different levels of relative-humidity and air movement on litter conditions, ammonia levels, growth, and carcass quality for broiler-chickens. Poult. Sci.70:746-755.
Weeks, C. A., C. J. Nicol, C. M. Sherwin, and S. C. Kestin.1994. Comparison of the behaviour of broiler chickens in indoor and free-range environments. Anim. Welf.3:179-192.
Weeks, C. A., T. D. Danbury, H. C. Davies, P. Hunt, and S. C. Kestin.2000. The behaviour of broiler chickens and its modification by lameness. Appl. Anim. Behav. Sci.67:111-125.
Whitehead, C. C.1977. The use of biotin in poultry nutrition. World's Poult. Sci. J.33:140-154.
Whitehead, C. C.1988. Biotin in Animal Nutrition. F. Hoffmann-La Roche & Co. Ltd., Basel, Switzerland.
Wong-Valle, J., G R. Mcdaniel, D. L. Kuhlers, and J. E. Bartels.1993. Correlated responses to selection for high or low incidence of tibial dyschondroplasia in broilers. Poult. Sci. 72:1621-1629.
Yan F, Angel R, Ashwell C, et al. Evaluation of the broiler stability to adapt to an early moderate def-iciency of phosphorus and calcium[J]. Poultry Science,2005,84(8):1232-1241.
Youssef, I. M. I., A. Beineke, K. Rohn, and J. Kamphues.2011. Effects of high dietary levels of soybean meal and its constituents (potassium, oligosaccharides) on foot pad dermatitis in growing turkeys housed on dry and wet litter. Arch. Anim. Nutr.65:148-162.
Youssef, I. M. I., A. Beineke, K. Rohn, and J. Kamphues.2012. Influences of increased levels of biotin, zinc or mannanoligosaccharides in the diet on foot pad dermatitis in growing turkeys housed on dry and wet litter. J. Anim. Physiol. Anim. Nutr. (Berl.) 96:747-761.
Yuan, L., H. Lin, K. J. Jiang, H. C. Jiao, and Z. G Song.2008. Corticosterone administration and high-energy feed results in enhanced fat accumulation and insulin resistance in broiler chickens. Br. Poult. Sci.49:487-495.
Zhang, X., G. R. Mcdaniel, Z. S. Yalcin, and D. L. Kuhlers.1995. Genetic correlations of tibial dyschondroplasia incidence with carcass traits in broilers. Poult. Sci.74:910-915.
Zulkifli I, Liew P K, Israf D A, et al. Effect of early age feed restriction and heat conditioning on heterophil/lymphocyte ratios, heat shock protein 70 expression and body temperature of heat stressed broiler chickens[J]. Thermal Biology,2003,28:217-222.