日粮添加不同比例的中短链和长链脂肪酸对奶牛免疫功能的影响

为探讨不同比例的中短链和长链脂肪酸混合物对奶牛免疫功能的影响,试验选用72头产奶量、胎次及泌乳日龄相近的中国荷斯坦奶牛,按随机区组试验设计,分为对照组和5个处理组,对照组饲喂基础日粮,处理组在基础日粮上分别添加400 g/d 长链脂肪酸(LCFA,A组)、80 g/d中短链脂肪酸(SMCFA)+320 g/d LCFA(B组)、400 g/d 黄油(C组)、240 g/d SMCFA+160 g/d LCFA(D组)及400 g/d SMCFA(E组)。试验期为63 d,第1周为预试期,试验期最后1 d采集血液样品,用于测定血清中免疫球蛋白及细胞因子的含量。结果显示,日粮添加不同比例的中短链和长链脂肪酸对奶牛血清中免疫球蛋白M(IgM)及前列腺素(PGE₂)的含量没有显著影响(P＞0.05);A组免疫球蛋白A(IgA)的含量显著高于B、E组(P＜0.05),B、D组免疫球蛋白G(IgG)的含量显著高于其余4组(P＜0.05)。日粮中添加脂肪酸均能提高奶牛血清中IL-4及IL-10的含量,尤其是D组,增加效果极显著(P＜0.01)。因此,添加240 g/d SMCFA 和160 g/d LCFA更能提高泌乳中期奶牛的免疫性能。

Effects of Supplementing Different Ratios of Short-medium Chain Fatty Acids and Long Chain Fatty Acids on the Immune Function in Mid-lactating Dairy Cows

The objective of this study was to investigate the effects of supplementing different ratios of short-medium chain fatty acids (SMCFA) and long chain fatty acids (LCFA) on the immune function in mid-lactating dairy cows. Seventy-two Chinese Holstein cows were blocked by the milk yield, lactation day age and parity, and then assigned to six groups. The animals were fed 0 g/d, 400 g/d LCFA, 80 g/d SMCFA, 320 g/d LCFA, 400 g/d butter fat, 240 g/d SMCFA and 160 g/d LCFA and 400 g/d SMCFA respectively on the basis of ordinary diets for the control, group A and group B,group C, group D and group E. The experiment lasted 63 days and on the last day, blood samples were collected to determine the concentrations of serum immunoglobulin IgA, IgG, IgM, prostaglandin E₂ (PGE₂ ) and cytokines. The results showed that among all the groups, IgM and PGE₂ were not affected by supplementing fatty acids (P＞0.05). The concentrations of IgA in group A was higher than that in groups B and E and the concentrations of IgG in groups B and D were higher than the other four groups(P＜0.05). Interleukin-4 and 10 increased after supplementing fatty acids, especially in group D(P＜0.01). In conclusion, supplementing fatty acids which consisted of 240 g/d SMCFA and 160 g/d LCFA could improve the immune functions in mid-lactating dairy cows well.