Effects of Dietary Cottonseed Oil and Cottonseed Meal Supplementation on Liver Lipid Content, Fatty Acid Profile and Hepatic Function in Laying Hens

Simple Summary Cottonseed by-products have been considered for use as nutrients in animal diets for a long time. However, the antinutrients, such as free gossypol and cyclopropene fatty acids, from cottonseed have caused numerous adverse effects on animal production. Commonly studies were concentrated on the toxicity of free gossypol, while the toxicity of cyclopropene fatty acids in cottonseed oil was neglected. The current study showed that dietary supplementation of degossypolized cottonseed oil containing cyclopropene fatty acids in diets contributed to dramatic changes in the fatty acid profile in tissues and elevated serum cholesterol level in hens. Therefore, it should raise public concerns about the application of cottonseed oil in both animal and human diets because of its long tradition of use in human food processing. Antinutrients, such as cyclopropene fatty acids (CPFAs) and free gossypol (FG), present together in cottonseed have caused numerous adverse effects on liver health and egg quality of laying hens, which are both likely to be related to a disturbance in lipid metabolism. This experiment employed a 3 x 3 factorial arrangement using corn-soybean-meal-based diets supplemented with different levels of cottonseed oil (0%, 2%, or 4% CSO) containing CPFAs and cottonseed meal (0%, 6%, or 12% CSM) containing FG to elucidate the effects of them or their interaction on fatty acid profile, lipid content, and liver health of laying hens. An overall increase in fatty acid saturation and an overall significant decrease (p < 0.05) in monounsaturated fatty acids (MUFAs) were shown in the livers of hens fed diets with either 2% or 4% CSO. Meanwhile, the concentration of liver cholesterol, serum cholesterol, and serum LDL-c of hens fed a diet supplemented with a high level of CSO (4%) were noticeably increased (p < 0.05). Even though the supplementation of 4% CSO in diets aroused beneficial influences on liver function, a high level of CSO inclusion in laying hens' diets is not recommended due to its hypercholesterolemia effect. In conclusion, supplementation of CSO, which contains 0.20% CPFAs, was the primary cause of alteration in fatty acid composition and cholesterol content in hens, while no interaction between CSM and CSO nor CSM effect was found for lipid profile and liver health in laying hen.