Use of water-treated black tea waste instead of wheat bran in laying hen diets

ABSTRACT We assessed the effects of different amounts of water-treated black tea waste (BTW) in the diets of laying hens on performance, egg quality, yolk peroxidation, and blood parameters in this study. The experiment lasted for 12 weeks, during which a total of 108 Lohman layers, of 24 weeks old, were randomly allocated to one of six dietary treatments (18 hens each); each treatment consisted of six replicate cages, each containing three hens. Experimental animals were fed a commercial diet that contained 0 (control), 20, 40, 60, 80, and 100% BTW in place of wheat bran. Providing BTW in diets for laying hens, instead of wheat bran, did not have a significant effect on egg production, egg weight, or body weight change. As the amount of BTW in the diet increased, feed intake, cracked egg rates, and feed conversion ratio linearly increased. Additionally, use of BTW in diets of laying hens did not influence some egg quality parameters, such as shape index or shell strength. Increasing proportions of BTW in the diet, however, had a quadratic effect on yolk color and shell weight, a linear effect on yolk index and shell thickness, and a cubic effect on albumen index and Haugh unit. In response to increasing BTW percentage, there were no differences in blood parameters except for albumen, triglyceride, alkaline phosphatase, and alanine aminotransferase levels. Malondialdehyde values in the egg yolks obtained from treatment groups fed diets containing BTW at different levels and stored for 14 and 28 days were lower than in those of the control group, but there were no differences at 56 days. Results of our study showed that supplementing diets of laying hens with different levels of water-treated BTW did not have adverse effects on either animal performance or egg quality parameters and resulted in strong antioxidative activity. Consequently, BTW may be used to replace up to 100% of wheat bran in the diets of laying hens, but the best outcomes are observed at 4% BTW level.

摘要 本研究旨在评估日粮中添加不同比例水处理红茶废弃物（water-treated black tea waste, BTW）对产蛋鸡（laying hens）生产性能、蛋品质（egg quality）、蛋黄过氧化（yolk peroxidation）及血液指标（blood parameters）的影响。本试验周期为12周，共选用108只24周龄罗曼蛋鸡（Lohman layers），随机分为6个日粮处理组，每组18只鸡；每个处理组设置6个重复笼，每笼饲养3只蛋鸡。试验组饲喂的商品基础日粮分别以0（对照组）、20%、40%、60%、80%、100%的BTW替代麦麸（wheat bran）。以BTW替代麦麸饲喂产蛋鸡，对产蛋率、蛋重及体重变化均无显著影响。当日粮中BTW添加比例升高时，采食量、破蛋率（cracked egg rates）及料重比（feed conversion ratio）呈线性升高趋势。此外，日粮添加BTW对蛋形指数（shape index）、蛋壳强度（shell strength）等部分蛋品质指标无显著影响。但日粮中BTW比例升高对蛋黄颜色与蛋壳重量（shell weight）呈现二次效应，对蛋黄指数（yolk index）及蛋壳厚度（shell thickness）呈现线性效应，对蛋白指数（albumen index）与哈氏单位（Haugh unit）呈现三次效应。随着日粮中BTW添加比例提升，除白蛋白（albumen）、甘油三酯（triglyceride）、碱性磷酸酶（alkaline phosphatase）及丙氨酸氨基转移酶（alanine aminotransferase）水平外，其余血液指标均无显著差异。饲喂不同比例BTW日粮的处理组，其鸡蛋在储存14天和28天时的蛋黄丙二醛（Malondialdehyde）值均低于对照组，但储存56天时各组间无显著差异。本研究结果表明，在产蛋鸡日粮中添加不同比例的水处理红茶废弃物，对动物生产性能与蛋品质指标均无不良影响，且可赋予较强的抗氧化活性。因此，BTW可在产蛋鸡日粮中替代最高100%的麦麸，但在添加4%的BTW时可获得最佳饲养效果。