Abstract:
The purpose of this experiment was conducted to investigate the effects of compound plant extracts from grape skin, hemp seed and aloe on performance, egg quality, serum biochemical indexes and immunity of laying hens. A total of 576 healthy Hy-Line gray hens aged 53 weeks were randomly divided into 4 groups(0.1%, 0.2%, 0.6% compound plant extracts group and control group) with 12 replicates in each group and 12 chickens in each replicate. The hens in the control group were fed a basal diet, and hens in 0.1%,0.2%,0.6% compound plant extracts groups were fed basal diet supplemented with 0.1%, 0.2% and 0.6% of compound plant extracts, respectively. The pre-feeding period was 14 d and the formal period was 56 d, the performance, egg quality, serum biochemical indexes and Newcastle disease virus antibody level of each group were determined. The results showed that compared with the control group, diet supplemented with 0.1%, 0.2% and 0.6% compound plant extracts groups significantly increased the laying rate, average egg weight and average daily egg production(P<0.05), and significantly reduce the egg breaking rate(P<0.05). The feed conversion rate in 0.6% compound plant extracts group was the lowest among trial groups. During the whole experiment period, the egg shape index in 0.1%, 0.2% and 0.6% compound plant extracts groups increased significantly compared with the control group(P<0.05), and the histone coefficient, yolk coefficient and Haugh unit in 0.2% and 0.6% compound plant extract groups were significantly higher than those of the control group(P<0.05). Compared with the control group, the contents of total cholesterol, triglyceride, low density lipoprotein cholesterol and alanine aminotransferase activity in serum in the 0.2% and 0.6% compound plant extract groups were significantly decreased(P<0.05), while the serum high density lipoprotein cholesterol contents and Newcastle disease antibody titers were significantly increased(P<0.05). There were no significant differences in serum total protein, albumin, uric acid contents, aspartate aminotransferase activity and mortality among the groups(P>0.05). The results indicated that adding a certain level of grape skin, hemp seed and aloe compound plant extracts in the diet of laying hens could improve the performance, egg quality and immunity of laying hens, and adding 0.6% compound plant extracts was more suitable.