肉牛日粮补饲硫酸锌对瘤胃发酵代谢的影响

选用4头装有永久性瘤胃瘘管的西门塔尔杂交肉牛，采用4×4拉丁方设计，研究日粮补饲不同无机锌（源于硫酸锌，水平为0、25、50和100 mg/kg干物质（DM））对瘤胃氨氮和挥发性脂肪酸（VFA）浓度的影响。试验结果表明，日粮补饲锌对瘤胃VFA浓度（产生量）有明显影响（p<0.05），与对照组相比，50、100 mg/kg DM的补饲明显提高乙酸、和总VFA的浓度（p<0.05），而日粮中锌的补饲对瘤胃页氨氮浓度和瘤胃VFA摩尔比例没有显著影响（p>0.05），每千克日粮补饲50和100 mg/kg DM 无机锌可明显促进瘤胃的发酵。

Effects of Dietary Zinc Supplementation as Zinc Sulfate on Rumen Fermentation in Steers

An experiment was conducted to determine the effect of supplemental Zn (as Zn sulfate) on rumen fermentation in steers. Four ruminally cannulated steers were fed, in a 4×4 Latin square design, 2.8 kg/d concentrate and 4.2 kg/d rice straw as a basic dietary. Treatments consisted of the following : control (no supplemental Zn) and 25 or 50 or 100 mg Zn/kg DM (on DM basis of dietary) from Zn sulfate. Rumen samples were collected at days 22, 23 and 24 of experiment period. There were significant effects of supplementation of Zn on concentrate of acetate, propionate, and total VFA (p< 0.05). The concentrate of ruminal NH3-N and the VFA molar proportions were not affected by the addition of Zn to diets (p>0.05). However, for comparing control (no supplementation), the concentrate of acetate and total VFA were higher with supplementation of 50 or 100 mg/kgDM Zn (p< 0.05). These results indicated that Zn-supplemented at 50 or 100 mg/kgDM improved rumen fermentation in steers.