摘要
本试验旨在研究低氮条件下不同能量水平饲粮对藏羊体外发酵特性及产气量的影响。试验以消化能(DE)分别为7. 37 (低能,LE)、8. 45 (中低能,MLE)、9. 54 (中高能,MHE)和10.62 MJ/kg(高能,HE)且粗蛋白质含量(6.26%)相同的4种饲粮作为发酵底物,以6只自然放牧的藏羊为瘤胃液供体,采用体外发酵法培养72 h,并对产气量、营养物质降解率以及挥发性脂肪酸(VFA)浓度等参数进行测定。结果表明:1)在发酵48和72 h时,HE组干物质降解率(DMD)均显著高于MHE、MLE和LE组(P<0.05)。在发酵4、8、12、24和72 h时,HE组中性洗涤纤维降解率(NDFD)均显著高于MHE、MLE和LE组(P<0.05)。在发酵各时间点,HE组酸性洗涤纤维降解率(ADFD)均显著高于MHE、MLE和LE组(P<0.05)。2)在发酵4、12和24 h时,HE组总产气量均显著高于MHE、MLE和LE组(P <0.05)。在发酵4、8、12、24和48 h时,HE组甲烷产量均显著低于MHE、MLE和LE组(P<0.05)。3)在发酵各时间点,HE组氨态氮(NH3-N)浓度均显著高于MHE、MLE和LE组(P<0.05)。4)在发酵8、12、24、48和72 h时,HE组pH均显著低于MHE、MLE和LE组(P<0.05)。在发酵各时间点,HE组总挥发性脂肪酸(TVFA)浓度均显著高于MHE、MLE和LE组(P<0.05)。在发酵各时间点,HE组丙酸比例均显著高于MHE、MLE和LE组(P<0.05)。综上所述,在低氮条件下,提高饲粮能量水平可显著提高藏羊体外发酵的营养物质降解率,增加TVFA浓度,降低甲烷排放;同时,这也说明了在冷季对藏羊补饲能量饲粮,可优化其瘤胃发酵特性,提高饲粮能量转化效率。
This study was conducted to investigate the effects of dietary energy level under lownitrogen condition on in vitro fermentation characteristics and gas production in Tibetan sheep. Six Tibetan sheep were chosen as donors for ruminal fluid. Four diets with the same crude protein (6.26%) content but different digestion energy (DE) levels [7.37 (lowenergy,LE),8.45 (middle lowenergy,MLE group),9.54 (middle high energy,MHE) and 10.62 MJ/kg (high energy,HE) ]were selected as substrates for in vitro fermentation. The samples were incubated for 72 h,and gas production,nutrient digestibility and volatile fatty acid (VFA) concentration were determined. The results showed as follows: 1) at 48 and 72 h of fermentation,dry matter degradation in HE group was significantly higher than that in MHE,MLE,LE groups (P<0.05). At 4,8,12,24 and 72 h of fermentation,neutral detergent fiber degradation in HE group was significantly higher than that in MHE,MLE,LE groups (P<0.05). At each time point of fermentation,acid detergent fiber degradation in HE group was significantly higher than that in MHE,MLE,LE groups (P<0.05). 2) At 4,12 and 24 h of fermentation,total gas production in HE group was significantly higher than that in MHE,MLE,LE groups (P<0.05). At 4,8,12,24 and 48 h of fermentation,methane production in HE group was significantly lower than that in MHE,MLE,LE groups (P<0.05). 3) At each time point of fermentation,ammoniacal nitrogen (NH3-N) concentration in HE group was significantly higher than that in MHE,MLE,LE groups (P <0.05). 4) At 4,8,12,24,48 and 72 h of fermentation,pH in HE group was significantly lower than that in MHE,MLE,LE groups (P<0.05). At each time point of fermentation,total volatile fatty acids concentration and propionic acid percentage in HE group were significantly lower than those in MHE,MLE,LE groups (P<0.05). It is concluded that increasing dietary energy level under lownitrogen condition can increase nutrient degradability and VFA concentration,but decrease methane production. Therefore, supplementing energy feedstuff to improve the energy intake of Tibetan sheep in cold season can improve the rumen fermentation characteristics.
引文
[1]赵有璋.羊生产学[M].2版.北京:中国农业出版社,2002.
[2]XIN G S,LONG R J,GUO X S,et al.Blood mineral status of grazing Tibetan sheep in the Northeast of the Qinghai-Tibetan Plateau[J].Livestock Science,2011,136(2/3):102-107.
[3]李孝仪,杨舒黎,马黎,等.西藏绵羊低氧适应的血液生理学特性研究[J].黑龙江畜牧兽医,2016(1):12-15.
[4]LONG R J,DING L M,SHANG Z H,et al.The yak grazing system on the Qinghai-Tibetan plateau and its status[J].The Rangeland Journal,2008,30(2):241-246.
[5]莫文生,杜雪燕,孙璐,等.不同能氮比精料对藏羊生长性能和血清指标的影响[J].黑龙江畜牧兽医,2017(13):122-125.
[6]祁生元,雷良煜.放牧藏羊冷季营养调控试验报告[J].青海畜牧兽医杂志,2012,42(4):24-25.
[7]张立,央金,洛桑催成,等.高原型藏绵羊春季补饲试验[J].西南农业学报,2017,30(4):975-977.
[8]丁考仁青,石红梅,张玉林,等.甘南藏羊高寒牧区冷季补饲育肥试验[J].畜牧兽医杂志,2011,30(6):28-29.
[9]马桂琳,祁红霞,刘秀,等.甘南藏绵羊冷季补饲试验研究[J].畜牧兽医杂志,2011,30(6):35-37.
[10]赵忠,王安禄,王宝全,等.藏系绵羊冷季补饲时限与措施优化研究[J].中国草食动物,2005,25(2):21-23.
[11]徐田伟,胡林勇,赵娜,等.补饲燕麦青干草对牦牛和藏系绵羊冷季生长性能的影响[J].西南农业学报,2017,30(1):205-208.
[12]ZHOU J W,GUO X S,DEGEN A A,et al.Urea kinetics and nitrogen balance and requirements for maintenance in Tibetan sheep w hen fed oat hay[J].Small Ruminant Research,2015,129:60-68.
[13]National Research Council.Nutrient requirements of sheep[M].Washington D.C.:National Academies,1985.
[14]ZHOU J W,MI J D,TITGEMEYER E C,et al.Acomparison of nitrogen utilization and urea metabolism betw een Tibetan and fine-w ool sheep[J].Journal of Animal Science,2015,93(6):3006-3017.
[15]王威,张建勋,康坤,等.冷季补饲精料对牦牛繁殖性能和生长性能的影响[J].中国畜牧杂志,2013,49(7):78-80.
[16]谢敖云,柴沙驼,王万邦,等.高山草甸草地牧草产量及其营养变化规律[J].青海畜牧兽医杂志,1996,26(2):8-10.
[17]中华人民共和国农业部.NY/T 816-2004肉羊饲养标准[S].北京:中国农业出版社,2004.
[18]熊本海,罗清尧,赵峰,等.中国饲料成分及营养价值表(2015年第26版)制订说明[J].中国饲料,2015(21):23-23.
[19]MENKE K H,STEINGASS H.Estimation of the energetic feed value obtained from chemical analysis and in vitro gas production using rumen fluid[J].Animal Research and Development,1988,28:7-55.
[20]张丽英.饲料分析及饲料质量检测技术[M].2版.北京:中国农业大学出版社,2003.
[21]MENKE K H,RAAB L,SALEWSKI A,et al.The estimation of the digestibility and metabolizable energy content of ruminant feedingstuffs from the gas production w hen they are incubated w ith rumen liquor in vitro[J].The Journal of Agricultural Science,1979,93(1):217-222.
[22]HRISTOV A N,IVAN M,RODE L M,et al.Fermentation characteristics and ruminal ciliate protozoal populations in cattle fed medium-or high-concentrate barley-based diets[J].Journal of Animal Science,2001,79(2):515-524.
[23]ERWIN E S,MARCO G J,EMERY E M.Volatile fatty acid analyses of blood and rumen fluid by gas chromatography[J].Journal of Dairy Science,1961,44(9):1768-1771.
[24]冯仰廉.反刍动物营养学[M].北京:科学出版社,2004.
[25]CHALUPA W.Manipulating rumen fermentation[J].Journal of Animal Science,1977,45(3):585-599.
[26]李婉,张爱忠,姜宁,等.不同精料水平对绒山羊体外发酵的影响[J].黑龙江畜牧兽医,2008(1):40-42.
[27]CHANDRAMONI,JADHAO S B,TIWARI C M,et al.Energy metabolism w ith particular reference to methane production in M uzaffarnagari sheep fed rations varying in roughage to concentrate ratio[J].Animal Feed Science and Technology,2000,83(3/4):287-300.
[28]梁静,张文举,王博.不同精粗比底物下添加复合营养调控剂对绵羊瘤胃微生物体外发酵的影响[J].家畜生态学报,2016,37(11):25-30.
[29]郭冬生,彭小兰.反刍动物挥发性脂肪酸消化代谢规律刍议[J].畜牧与饲料科学,2005(1):1-3.
[30]王中华.反刍动物挥发性脂肪酸中间代谢[J].草食家畜,1995(2):23-31,34.
[31]张海波,王之盛.精料补充料能量水平对肉牛瘤胃发酵特性及微生物菌群的影响[J].中国畜牧杂志,2017,53(9):97-101.
[32]高天爽,孙海霞,谢小来,等.日粮中高粱替代玉米对绵羊瘤胃发酵的影响[J].黑龙江畜牧兽医,2014(5):7-10.
[33]BEUVINK J M W,SPOELSTRA S F.Interactions betw een substrate,fermentation end-products,buffering systems and gas production upon fermentation of different carbohydrates by mixed rumen microorganisms in vitro[J].Applied M icrobiology and Biotechnology,1992,37(4):505-509.
[34]姜鑫,刘帅,徐宏建,等.玉米蛋白水解物对奶牛瘤胃体外发酵及纤维素酶活的影响[J].中国饲料,2018(3):60-65.
[35]BACH A,CALSAMIGLIA S,STERN M D.Nitrogen metabolism in the rumen[J].Journal of Dairy Science,2005,88(Suppl.1):E9-E21.