Effect of different dietary carbohydrate structure on fermentation and amino acid profile of microorganisms in the rumen of goats | 不同碳水化合物结构日粮对山羊瘤胃发酵和微生物氨基酸组成的影响

Chinese. 【目的】研究日粮中不同碳水化合物结构对山羊瘤胃发酵和微生物氨基酸组成的影响,为回答“瘤胃微生物的氨基酸组成是否恒定？”这一国际学术界仍有争论的问题提供理论依据。【方法】选用4头装有永久性瘤胃瘘管的徐淮山羊,采用4×4拉丁方试验设计,以玉米、豆粕、稻草为基础日粮,研究不同非结构性碳水化合物与结构性碳水化合物之比(NSC/SC)处理(A：0.33、B：0.63、C：1.17及D：2.18)对pH、NH3-N、VFA浓度及瘤胃微生物氨基酸组成的影响。【结果】随着日粮中NSC/SC的升高,瘤胃pH显著降低(P＜0.05),NH3-N浓度显著升高(P＜0.05),乙酸的摩尔百分比和乙酸/丙酸的比值随日粮中NSC/SC的升高而显著降低(P＜0.05)。不同NSC/SC的日粮下的细菌氨基酸含量中,天冬氨酸、丝氨酸、甘氨酸、缬氨酸、蛋氨酸、亮氨酸、苯丙氨酸、组氨酸、精氨酸、脯氨酸含量都存在显著差异或极显著差异(P＜0.05),原虫氨基酸中天冬氨酸、丙氨酸、亮氨酸、苯丙氨酸、赖氨酸、组氨酸、脯氨酸产生了显著变化(P＜0.05)。【结论】瘤胃微生物氨基酸组成会受到日粮中NSC/SC比例的影响。

English. 【Objective】 The main objective was to investigate the effect of different dietary carbohydrate structure on fermentation and variation in amino acid profile of microorganisms in the rumen of goats, and to provide evidence for a global debate whether amino acids profile in the rumen microbes is constant or not.【Method】Four Xuhuai goats fitted with permanent rumen cannulas were used in a 4×4 Latin Square design experiment. Diets based on corn, soybean meal and rice straw were divided into 4 treatments according to ratio of nonstructural and structural carbohydrates (A: 0.33, B: 0.63, C: 1.17, D: 2.18). The experiment was conducted to determine the effect of dietary NSC/SC on rumen fermentation patterns and the amino acid profile variation of rumen microbes.【Result】 With the increase of dietary NSC/SC, there were some tendencies that the rumen pH decreased significantly (P＜0.05), NH3-N concentration in rumen increased significantly (P＜0.05). The percent of acetate decreased, the percent of propionate increased, and the ratio of acetate to propionate decreased in rumen significantly (P＜0.05) corresponding with the increase of dietary NSC/SC. Some amino acids concentration of rumen bacteria varied significantly (P＜0.05), such as Asp, Ser, Gly, Val, Met, Leu, Phe, His, Arg, and Pro. Different NSC/SC ratios also affected some protozoa amino acids, such as Asp, Ala, Leu, Phe, Lys, His, Arg, and Pro. 【Conclusion】 It is concluded that amino acid profile derived from rumen microbes is mainly variable with dietary carbohydrate structure in term of NSC/SC ratio.