Abstract:

【Objective】 To investigate the effects of alfalfa supplementation on nutrient apparent digestibility, rumen fermentation parameters and rumen microflora structure of Hu lambs aged from 15 to 55 days. 【Methods】 Forty-eight second-litter double-lamb lake lambs with body weight of (4.22±0.35) kg were randomly divided into 3 groups with 4 replicates per group. They were fed diets containing 10% (M1), 20% (M2) and 30% (M3) alfalfa, respectively. According to the different feeding and management of lambs, the experiment was divided into 15~34 days of age and 35~54 days of age. 【Results】 The results showed as follows: At 54 days of age, the body weight of 30% alfalfa group was higher than that of other experimental groups, but there was no significant difference (P > 0.05); At 15 to 34 days of age and 35 to 54 days of age, there were no significant differences in the apparent digestibility of dry matter, crude protein, neutral detergent fiber and acid detergent fiber among treatment groups (P > 0.05). There was no significant difference in pH among experimental groups (P > 0.05), NH₃-N content of 10% alfalfa group was significantly higher than that of 20% alfalfa group and 30% alfalfa group (P < 0.05), and the contents of total volatile fatty acids, acetic acid and butyric acid of 30% alfalfa group were significantly higher than those of 10% alfalfa group (P< 0.05). The activities of cellulase, xylanase and pectinase in 10% alfalfa group were significantly higher than those in 30% alfalfa group (P < 0.05); The Shannon index of 30% alfalfa group was significantly higher than that of 10% alfalfa group and 20% alfalfa group (P<0.05). The abundance of firmicutes in 20% alfalfa group and 30% alfalfa group was increased compared with 10% alfalfa group (0.05 < P≤0.10), but there were no significant differences in the levels of other rumen bacteria among experimental groups (P > 0.05). The abundance of Prevotella in 10% alfalfa group was significantly higher than that in other experimental groups (P<0.05), and the abundance of Eurosenia in 30% alfalfa group was significantly higher than that in other experimental groups (P<0.05). The number of bacterial amine and polyamine biosynthesis pathways in 20% alfalfa group was significantly higher than that in other experimental groups (P<0.05), and the number of aminoacyl-trNA pathway and aromatic compound biosynthesis pathway in 30% alfalfa group was significantly higher than that in 10% alfalfa group (P< 0.05). The number of metabolic regulator biosynthesis pathways in 30% alfalfa group was significantly lower than that in other experimental groups (P < 0.05). 【Conclusion】 According to the results, it is appropriate to add 20%-30% alfalfa in the diet of lambs aged from 15 to 55 days.

Key words: alfalfa; lamb; nutrient digestibility; rumen environment; rumen microbiota; non-fiber carbohydrates

摘要：

【目的】研究补饲苜蓿对15~55日龄湖羊羔羊养分表观消化率、瘤胃发酵参数及瘤胃微生物菌群结构的影响。【方法】试验选取48只体重(4.22±0.35) kg的第二胎次的双羔湖羊羔羊,随机分为3组,每组4个重复,分别饲喂含有10%(M₁)、20%(M₂)、30%(M₃)苜蓿的饲粮,根据羔羊饲养管理的不同将试验分为15~34日龄和35~54日龄。【结果】54日龄时,30%苜蓿组羔羊体重较其它试验组有所提高,但无显著差异(P>0.05);15~34、35~54日龄,各处理组干物质表观消化率、粗蛋白质表观消化率、中性洗涤纤维表观消化率和酸性洗涤纤维表观消化率无显著差异(P>0.05);各试验组pH值无显著差异(P>0.05),10%苜蓿组NH₃-N含量显著高于20%苜蓿组组和30%苜蓿组组(P<0.05),30%苜蓿组的总挥发性脂肪酸、乙酸和丁酸含量显著高于10%苜蓿组(P<0.05);10%苜蓿组的纤维素酶、木聚糖酶和果胶酶活显著高于30%苜蓿组(P<0.05);30%苜蓿组Shannon指数显著高于10%苜蓿组和20%苜蓿组(P<0.05);20%苜蓿组和30%苜蓿组的厚壁菌门丰度与10%苜蓿组相比有提升的趋势(0.05<P≤0.10),各试验组瘤胃细菌其他门水平无显著差异(P>0.05);10%苜蓿组普雷沃氏菌属丰度显著高于其他试验组(P<0.05),30%苜蓿组欧陆森氏菌属丰度显著高于其他试验组(P<0.05);20%苜蓿组瘤胃细菌胺和多胺生物合成通路数量显著高于其他试验组(P<0.05),30%苜蓿组氨酰-tRNA通路和芳香族化合物生物合成通路数量显著高于10%苜蓿组(P<0.05),30%苜蓿组代谢调节剂生物合成通路数量显著低于其他试验组(P<0.05)。【结论】15~55日龄羔羊饲粮中添加20%~30%的苜蓿为宜。

关键词: 苜蓿, 羔羊, 养分消化率, 瘤胃内环境, 瘤胃微生物菌群, 非纤维性碳水化合物