Effects of different levels of cottonseed meal on laying performance, egg quality, intestinal immunity and hepatic histopathology in laying hens

The experiment was conducted to evaluate the effects of different levels of cottonseed meal (CSM) in laying hens. A total of 175 hens, 60-wk-old, were allocated to five treatments. The control group was fed a corn-soybean meal diet, and the four experimental diets contained 19.5, 67.5, 115.5, and 163.5 g/kg CSM, in which free gossypol level was 20, 70, 120, 170 mg/kg, respectively. The results showed that no significant differences were observed on laying performance, egg production and organ indexes among all groups. Jejunum and ileum mucosa slgA were significantly lower than the control group when FG reached 120 mg/kg (P < 0.05). The ileum IL-2 was significantly decreased when FG reached 70 mg/kg (P < 0.05). The ileum TNF-alpha was increased linearly and the liver damage was aggravated with the increase of FG. In conclusion, FG can destroy intestinal immunity and liver tissue and dietary FG in laying hens should be limited within 70 mg/kg.