Zinc and vitamin E in diets for broilers reared under heat stress

The objective of this research was to evaluate the use of zinc and vitamin E in diets for broilers kept in reused litter, between 1-21 days of age, over performance, lymphoid organs, heart and digestive organs weight. Seven hundred chicks distributed in a completely randomized design in a factorial scheme 2x3+1, with two levels of zinc (0.0 and 120 mg/kg diet) associated with three levels of vitamin E (0.0, 300 and 600mg/kg diet), a control diet and five replications, were created in sheds covered masonry ceramic tiles and concrete floor . In the period of 1-21 days the weight gain is greater, without supplementation of zinc and vitamin E, when birds are kept on reused litter compared to those kept on new litter. The isolated supplementation of 300mg vitamin E/kg and the combination of 120mg zinc/kg with 600mg vitamin E/kg gives greater weight gain for broilers raised on reused litter compared to birds fed in a control diet kept in new litter. We conclude that the reviews levels of zinc and vitamin E do not improve feed intake, weight gain, feed conversion, the production viability and productive efficiency rate of broilers kept in re-used litter of 1 to 21 days of age. The intestine weight increases and the spleen's decreases as vitamin E is supplemented in the diets of these animals.

本研究旨在评估1~21日龄、饲养于重复使用垫料的肉仔鸡日粮中添加锌与维生素E，对其生长性能、淋巴器官、心脏及消化器官重量的影响。试验共选用700羽雏鸡，采用完全随机设计，设置2×3+1因子方案：两个锌添加水平（0.0与120 mg/kg日粮）分别与三个维生素E添加水平（0.0、300与600 mg/kg日粮）组合，另设基础对照日粮，每组设置5个重复。试验鸡群饲养于铺设有混凝土地板、屋顶覆盖釉面陶瓷砖的鸡舍中。
在1~21日龄阶段，未添加锌与维生素E的试验组中，饲养于重复使用垫料的肉仔鸡体重增益高于饲养于新垫料的个体。单独添加300 mg/kg维生素E，以及120 mg/kg锌与600 mg/kg维生素E的组合添加组，其饲养于重复使用垫料的肉仔鸡体重增益，均高于饲养于新垫料且饲喂基础对照日粮的鸡只。
本研究得出结论：在1~21日龄饲养于重复使用垫料的肉仔鸡日粮中，所测试的锌与维生素E添加水平均未能改善其采食量、体重增益、饲料转化率、生产存活率及生产效率。当日粮中添加维生素E时，肉仔鸡的肠道重量升高，脾脏重量降低。