On growth performance, nutrient digestibility, blood T lymphocyte subsets, and cardiac antioxidant status of broilers.

Different lipid sources differ in the fatty acid profiles and differently affect growth performance as well as immune function of broilers. The influences of different dietary lipid sources on growth performance, nutrient digestibility, blood T lymphocyte population, and cardiac antioxidant status were investigated of broilers. A total of 360 one-day-old male broilers (BW = 44 ± 3 g) were randomized into 3 treatment groups, consisting of 6 replicates with 20 birds in each group. Broilers received standard diets supplemented with 5% (wt/wt) of lard (LD, as a control diet), sesame oil (SO), or flaxseed oil (FO). Broilers in both SO and FO treatment groups had lower (P < 0.05) feed conversion ratios from 22 to 42 d and during the overall phase compared to those in LD treatment group. Meanwhile, the apparent total tract nutrient digestibility of crude fat in SO and FO treatment groups was higher than that in LD treatment group. Both FO and SO treatments decreased (P < 0.05) abdominal fat percentage compared to LD treatment. Total triglycerides and total cholesterol in chicken blood were decreased (P < 0.05) by SO and FO treatments compared to LD treatment. Feeding broilers with FO and SO led to a decrease (P < 0.05) in blood CD4⁺ T lymphocyte count and in CD4⁺:CD8⁺ ratio compared to LD treatment. Sesame oil and FO treatments increased cardiac glutathione peroxidase (P < 0.05) compared to LD treatment. It is concluded that addition of 5% SO and FO to the standard corn-soybean meal diet improved feed efficiency, increased the activities of cardiac glutathione peroxidase, and affected the T lymphocytes ratio of fast growing broilers.