Effect of diet at different energy levels on milk casein composition of Girgentana goats differing in CSN1S1 genotype

详细信息	查看全文 | 推荐本文 |

• 作者：B. Valenti^a ; ^{bernardo.valenti@unict.it} ; R.I. Pagano^b ; M. Avondo^b
• 关键词：Milk ; Goat ; Casein composition ; CSN1S1 polymorphism
• 刊名：Small Ruminant Research
• 出版年：2012
• 期刊代码：94_09214488
• 类别：abs
• 出版时间：June, 2012
• 卷：105
• 期：1-3
• 页码：135-139
• 文件大小：368 K

摘要

Eighteen Girgentana lactating goats, nine homozygous for strong alleles (AA) and nine homozygous for weak alleles (FF) at 伪_s1-casein (CSN1S1) locus, were used to evaluate the effect of genotype, diet and genotype 脳 diet (G 脳 D) interaction on the composition of goat milk caseins. Goats were used in a 2 脳 2 factorial arrangement of treatments, with two genotypes (AA, FF) and two diets at different energy levels (high-energy diet (D65) and low-energy diet (D100)). The experiment consisted of two simultaneous 2 脳 2 Latin squares for the two genotypes, with one square for each level of energy. Capillary electrophoresis was used for the determination of relative casein (CN) composition. 伪_s1-CN, 魏-CN and 尾-CN yield was significantly higher with D65 than D100 (10.2 vs 7.2; 3.8 vs 2.6; 18.6 vs 13.6 g/d, respectively). Genotype significantly affected (P < 0.05) 伪_s2-CN and 伪_s1-CN yield: 伪_s1-CN was higher in AA than FF goat milk (15.5 vs 2.4 g/d), while 伪_s2-CN was higher in FF than AA goat milk (4.7 vs 2.8 g/d); no genotype effect (P > 0.05) was reported for 魏-CN and 尾-CN yield. As concerning individual casein concentration, 伪_s1-CN was higher for AA than FF goat (12.4 vs 1.5 g/kg milk), whereas 伪_s2-CN and 尾-CN were higher in FF than AA milk (4.3 vs 1.4; 15.6 vs 12.9 g/kg, respectively); also 魏-CN tended to be higher in FF goats. Diet did not significantly influence concentration of individual caseins. A significant G 脳 D interaction was found only for 伪_s1-CN concentration, which decreased (鈭?0%) when AA goats shifted from D100 to D65. In conclusion, high energy input consistently improved total casein yield beside genotype. The higher casein yield of AA goats mainly depends on 伪_s1-CN biosynthesis; moreover, the lower presence of 伪_s1-CN in FF goat milk may be partially counterbalanced by the other caseins.