亮氨酸对早期断奶湖羊瘤胃发育及细菌菌群的影响

本试验旨在研究日粮中添加亮氨酸对早期断奶湖羊瘤胃发育及瘤胃细菌菌群组成的影响。选用36只5日龄的湖羊羔羊,依据体重相近原则随机分成对照组(C,0 g/d)、亮氨酸低剂量添加组(L,0.66 g/d)和高剂量添加组(H,1.33 g/d),每组4个重复,每个重复3只羔羊。于30日龄断奶当天每组每个重复取1只羔羊屠宰以获得瘤胃组织及内容物样品(n=4)。结果表明:H组瘤胃乳头的长度较C组显著增加(线性,P<0.01);添加亮氨酸可使瘤胃挥发性脂肪酸水平显著提高(二次,P=0.05),但并未改变乙酸、丙酸和丁酸的摩尔比例(P>0.05);与C组相比,L与H组的瘤胃氨态氮浓度均显著降低(线性,P<0.05;二次,P>0.05);L组羔羊瘤胃内容物中微生物蛋白含量显著高于C组(二次,P=0.05);亮氨酸的添加并未改变瘤胃细菌物种丰富度和多样性指数,但对菌群组成有一定影响;L组瘤胃内最多的是厚壁菌门(49.5%);H组拟杆菌门(51.4%)显著高L和C组(二次,P=0.05);H组的普雷沃氏菌属最多(线性,P>0.05;二次,P>0.05),而L组的巨型球菌属最多(二次,P <0.01);与C组相比,L组的双歧杆菌属(二次,P<0.05)和光岗菌属显著增加(二次,P<0.05)。由此可见,添加亮氨酸可促进羔羊瘤胃发育,改变瘤胃细菌菌群组成。

Effects of Leucine Addition on Rumen Development and Rumen Bacterial Communities of Early Weaned Hu Lambs

This study was conducted to investigate the effects of leucine addition on the rumen development and rumen bacterial communities of early weaned Hu lambs. Thirty-six healthy male Hu lambs at 5 d of age were assigned to three leucine addition treatments: control(C, 0 g/d), low addition level(L, 0.66 g/d), and high addition level(H, 1.33 g/d), with4 replicates in each treatment. After weaned at 30 d, one lamb was randomly selected from each replicate and slaughtered to collect samples of ruminal content and tissue(n=4). The results showed as follows: as compared to C group, lambs in H group had longer rumen papillae(linear, P<0.01). Addition of leucine increased volatile fatty acid concentrate(quadratic, P=0.05),but had no effect on the molar proportion of acetate, propionate or butyrate(P>0.05). Rumen NH3-N was decreased by leucine addition(linear, P<0.05; quadratic, P>0.05), while microbial protein was higher in L group than in C group(quadratic,P=0.05). Addition of leucine had no effect on rumen bacterial species richness or diversity index, but could affect the bacterial communities. At the phylum level, the abundance of Firmicutes was richer in L group(49.5%), while the abundance of Bacteroidetes in H group was higher(51.4%) than the other two groups(quadratic, P=0.05). At the genus level, Prevotella was richer in H group than in L group(linear, P>0.05; quadratic, P>0.05). As compared to the C group, Bifidobacterium(quadratic,P<0.05), Megasphaera(quadratic, P<0.01), and Mitsuokella(quadratic, P<0.05) were increased significantly in L group. These results indicate that addition of leucine could improve the rumen development and change the communities of rumen bacterial.