日粮补充过瘤胃硫酸锌对肉牛瘤胃营养物质降解率的影响

Effects of dietary rumen-protected zinc supplementation on nutrient degradability of steers

为研究过瘤胃硫酸锌对肉牛瘤胃营养物质瘤胃降解率的影响,试验选用4头,24月龄,体重(513±5.7)kg的装有永久性瘤胃瘘管的晋南牛阉牛,采用4×4拉丁方试验设计,对照组日粮中添加300 mg锌(ZnSO47H2O),LRPZn、MRPZn和HRPZn组分别在日粮中添加200、300和400 mg的锌(过瘤胃硫酸锌,RPZn)。结果表明,玉米青贮干物质和有机物的有效降解率从高到低依次为HRPZn、MRPZn、LRPZn和对照组差异显著(P<0.05);中性洗涤纤维有效降解率HRPZn组显著高于其余各组(P<0.05)。混合精料干物质和有机物有效降解率HRPZn组显著高于对照组(P<0.05);粗蛋白质有效降解率HRPZn组显著高于对照组和LRPZn(P<0.05)。肉牛日粮中以过瘤胃硫酸锌形式添加400mg锌对提高日粮养分瘤胃降解率效果最佳。

The effects of rumen-protected zinc（RPZn）supplementation on nutrient degradability of steers were studied.Four ruminally fistulated Jinnan beef steers（24 months of age and（513±5.7）kg of body weight）were used in a 4×4 Latin square experimental design.The treatments were：control（with 300 mg/d of zinc as ZnSO47 H2 O）,low RPZn（LRPZn）,medium RPZn（MRPZn）and high RPZn（HRPZn）with 200,300 and 400 mg/d of zinc as RPZn,respectively.The effective degradability（ED）of dry matter and organic matter in corn silage was the highest for HRPZn,followed by MRPZn and then LRPZn,and the lowest for control（P〈0.05）.The ED of neutral detergent fibre in corn silage was significantly higher for HRPZn compared with other groups（P〈0.05）.The ED of dry matter and organic matter in concentrate was significantly higher for HRPZn compared with control（P〈0.05）.The ED of crude protein in concentrate was significantly higher for HRPZn than for control and LRPZn（P〈0.05）.The results indicated that the optimum dose for improving nutrient degradability was 400 mg Zn as RPZn supplementation in steers.