高锌日粮长期暴露对断奶仔猪生长性能和血清生化指标的影响

试验选用60头日龄相近(23±1)临床检查健康的“杜×长×大”三元杂交断奶仔猪，按体重和性别随机分成3组，每组20头，分别饲喂基础日粮、基础日粮+3000 mg/kg 氧化锌、基础日粮+500 mg/kg 蛋氨酸锌。在断奶后0、21、42、70 d，每组随机选取10头仔猪，前腔静脉采血，测定部分血清生化指标。结果表明，在断奶后0~42 d，添加高锌日粮组仔猪的体重和日增重显著（P<0.05)或极显著（P<0.01)高于对照组仔猪，而在断奶后42~70 d，对照组仔猪日增重显著高于添加高锌日粮组仔猪（P<0.05）；在断奶后42~70 d，添加高锌日粮组仔猪血清AST和ALT水平显著(P<0.05)或极显著(P<0.01)高于对照组仔猪，而血清TP、ALB水平显著（P<0.05)或极显著（P<0.01)低于对照组仔猪；在断奶后21~70 d，添加高锌日粮组仔猪血清ALP水平极显著高于对照组仔猪（P<0.01）。因此，断奶仔猪早期饲喂高锌日粮能显著缓解仔猪断奶应激，而长期饲喂高锌日粮对断奶仔猪有毒副作用。

Effect of High Zinc Diet Long-term Exposure on Growth Performance and Serum Biochemical Indexes in Piglets

To study the effect of high zinc diet long-term exposure on growth performance and serum biochemical indexes, sixty “Duroc×Landrace×Yorkshire” crossbred weanling piglets (23 ±1 days of age) were randomly divided into 3 groups with 20 piglets each by weight and sex, fed with basal diet, basal diet plus 3000 mg/kg zinc (from ZnO), and basal diet plus 500 mg/kg zinc (from Zn Met), respectively. Blood samples in 10 piglets from each group were taken on 0，21，42，70 d after weaning for measuring serum biochemical indexes. The results showed that high zinc diets increased significantly (P<0.05 or P<0.01) absolute weigh(AW) and average daily gain(ADG) of weanling stress piglets on 0~42 d postweaning, and dreased significantly (P<0.05) the average daily gain on 42~70 postweaning. The serum AST and ALT levels were significantly (P<0.05 or P<0.01) higher in piglets of treating group than that in piglets of control group on 42~70 postweaning , and the serum TP and ALB levels were significantly (P<0.05 or P<0.01) lower. High zinc diets increased significantly (P<0.01) ALP levels of weanling stress piglets on 21~70 d postweaning. The results indicated that feeding high zinc diets can remarkably degrade weanling piglets stress on the earlier period, but high-zinc diet long term exposure to weanling piglets caused poisoning response.