低锌日粮补锌对断奶前后犊牛免疫机能的影响

KFFECT OF ORAL SUPPLEMENTAL ZINC ON THE SYSTEM OF CALVES ABOUND WEANING

本文报道了低锌基础日粮中添加不同水平锌对断奶前后犊牛日增重及免疫机能的影响。结果表明：日粮中添加２０、４０，８０ｍｇ／ｋｇ锌可明显提高犊牛日增重，提高外周血Ｔ淋巴细胞转化指数和淋巴细胞ＡＮＡＥ染色率以及特异性抗原兔血红细胞的抗体滴度，降低血清中γ－球蛋白含量，其中以４０ｍｇ／ｋｇ组效果最佳。

The effects of zinc for Holstein female calves around weaning from 30 to 128 daysof age on daily gain、serum albumin、immune responseswere investigated.Five health female calves born in February, March and April,1991 were selectedseparately each month as three random groups. The calves in each groups were randomlydivided into 4 levels(A、B、C、D).B, C, D as treatment groups(each group contain3calves) had 20, 40, 80ppm of zinc(ZnSO4·7H2O)supplemented oraley,respectively.A(6 calves) as control group had no zinc added.Daily gains were increased 3.2%,9.5%,7.9% for B,C, D respectively comparedwith control group A. The effect were much more obvious after weaning, when stressfactors increased. Serum albumin content was higher in treatment groups than in controlgroup. LSI(Lymphocyte stimuldtion indices) from sixth week in B, C groups were higherthan in A(P<0.05). C group was better than B, but the difference was not significant(P>0.05).Only in eighth week the LSI of D group was higher than that of A(P<0. 05)Lymphocyte Positive rate increased in B,cgroups compared with A from forthweek of expriment(P<0. 05).C group was better than B,D better than A, but inboth cases was not signiflcant(P>0. 05). The mean antibody titres to rabbit red blood cells were higher for B,C, D groupsthan that for A(P<0.05).But from seventh week, diference between A and D groupwas not significant(P>005). Serum γ-globuein content was lower for B,C, D groupsthan that for A, after weaning the effect was much clearer.