富铜酵母对西门塔尔牛阉牛瘤胃发酵及尿嘌呤衍生物的影响

Effects of Copper-enriched Yeast on Rumen Fermentation and Purine Derivatives in Urine of Simmental Steers

本文旨在研究富铜酵母对瘤胃发酵和尿嘌呤衍生物浓度的影响。选用4头体重(420±15.2)kg、年龄2.5岁、装有永久性瘤胃瘘管的中国西门塔尔牛阉牛,采用4×4拉丁方设计,对照组饲喂基础日粮,处理1、2、3组分别在基础日粮干物质基础上添加富铜酵母(含铜10%)80、160和240mg/kg。结果表明:瘤胃pH和挥发性脂肪酸(VFA)无显著差异(P>0.05);160和240mg/kg组氨态氮(NH3-N)浓度显著低于对照组和80mg/kg组(P<0.05),240mg/kg组乙酸/丙酸比例低于对照组和80mg/kg组(P<0.05)。玉米秸秆和豆粕的干物质(DM)以及有机物(OM)有效降解率无显著差异,240mg/kg组玉米秸秆中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)有效降解率显著降低(P<0.05),160和240mg/kg组豆粕粗蛋白质(CP)有效降解率显著降低(P<0.05)。尿酸含量无显著变化,80和160mg/kg组尿囊素和尿嘌呤衍生物含量显著高于对照组和240mg/kg组(P<0.05)。在本试验条件下,富铜酵母添加量在每千克干物质80～160mg时效果较好;考虑在不同生产条件下,基础日粮中的铜水平有所不同,建议在以富铜酵母为日粮铜源时,日粮铜水平不可超过每千克干物质13.87mg。

The objective was to explore the effects of copper-enriched yeast on rumen fermentation and urinary excretion of purine derivatives of Simmental steers. Four healthy Simmental steers, with permanent ruminal cannulars and similar body weights of （420± 15.2） kg, at the age of 2.5 years, were used in a 4 × 4 Latin square experiment. There were the control group without copper-enriched yeast, treatment one, two and three supplemented with 80, 160 and 240 mg/kg of copper-enriched yeast （10% of copper） per steer per day, respectively. The results showed that ruminal pH and VFA were not affected by supplemental copper-enriched yeast significantly （P〉0.05）. NH3-N concentration in 160 and 240 mg/kg groups were lower than that in control and 80 mg/kg groups significantly （P〈0.05）. The ratio of acetic acid to propionic acid in 240 mg/kg group was lower than that in control and 80 mg/kg groups significantly （P〈0.05）. DM and OM effective degradability of corn straw and soybean were not significantly affected （P〉0.05）. NDF and ADF effective degradability of corn straw in 240 mg/kg group was decreased significantly （P〈0.05）. CP effective degradability of soybean in 160 and 240 mg/kg groups were decreased significantly （P〈0.05）. The content of urine acid was not significantly affected. Allantoin and urinary excretion of purine derivatives in 80 mg/kg and 160 mg/kg groups were higher than those in control and 240 mg/kg groups significantly （P〈0.05）. In this experiment, the optimal dose of copper-enriched yeast was 80-160 mg in per kilogram DM, but considering that the copper level in basal diet should be different with different production conditions, it is suggested that the copper level should not be more than 13.87 mg in per kilogram DM when copper is supplemented as copper-enriched yeast.