日粮精粗比对山羊瘤胃内微生物蛋白微循环的影响

 【目的】以4只装有瘤胃瘘管的山羊为试验动物，研究不同精粗比日粮对山羊瘤胃微生态中原虫和细菌区系以及微生物蛋白微循环的影响规律。【方法】试验设精（玉米-豆饼）粗（稻草）比分别为10﹕90、30﹕70、50﹕50和70﹕30的4种日粮（A、B、C、D），采用4×4拉丁方设计进行饲喂试验，采用荧光染色细菌技术测定瘤胃原虫对细菌的吞噬速率。【结果】日粮精粗比显著影响微生物细胞的密度。原虫密度C组最高;细菌和原虫的密度A组最低;日粮精粗比显著影响原虫吞噬的速率，A、B、C、D 4组的吞噬速率分别为：429.5、366.74、389.48、402.2 cells?cell-1?h-1，换算为对细菌N的吞噬速率分别为：2.319、1.98、2.103、2.172 pg N?cell-1?h-1。【结论】每天每头羊由于原虫的吞噬而造成的细菌N的循环损失估算分别为：136.49;369.02;485.99;440.56 mgN/（d?头），即菌体蛋白损失为0.853、2.306、3.370和2.754 g/（d?头），其中以C组菌体蛋白循环损失量最大，细菌周转率最高（3.07%）。

Effects of Dietary Concentration to Forage Rate on Microbial Protein Recycling in Rumen of Goats

【Objective】Studies on effects of dietary concentration to forage rate on microbial protein recycling in rumen of goats were carried out using a technique of fluorescence-labeled bacteria (FLB). 【Method】 In an experiment, 4×4 Latin squares were conducted by using four Xuhuai goats with permanent cannulas, and diets were divided into A (10﹕90), B (30﹕70), C (50﹕50), and D (70﹕30) by varying concentration to forage ratios, which concentrated food were corn-soybean meal, while forage was straw. 【Result】 The result showed that, rumen micro-ecosystem was changed significantly by concentration to forage rate. The highest protozoal density was recorded in group C which the dietary concentration to forage rate was set as 50:50, whereas densities of both protozoa and bacteria were lowest in group A; grazing rates of rumen protozoa on bacteria were 429.5, 366.74, 389.48, and 402.2 cells?cell-1?h-1, respectively in group A, B, C, and D. When the corresponding values expressed as bacteria-N were: 2.319, 1.98, 2.103, and 2.172 pg N?cell-1?h-1, respectively.【Conclusion】Extrapolating the assimilation of quantity of nitrogen by ciliates on bacteria of Xuhuai goat with different diets, there were 136.49, 369.02, 485.99, and 440.56 mg N/(d?capita) in groups A, B, C, and D, respectively. It was estimated that the protein losses due to microbial recycling were 0.853, 2.306, 3.370, and 2.754 g/(d?capita), respectively, with group C recording the highest bacterial protein loss and turnover rates (3.07%).