Effects of varied molecular weight of chitosan oligosaccharides on growth performance, carcass trait, meat quality, and fat metabolism in indigenous yellow-feathered chickens

The effect of varied molecular weight (MW) chitosan oligosaccharides (COS) supplementation on growth performance, carcass trait, meat quality and fat metabolism in indigenous yellow-feathered chickens was investigated. A total of 400-day-old female Lingnanhuang yellow-feathered chicks were randomly allotted to 1 of 5 treatments (8 replicate cages of 10 chicks per cage) and fed a corn-soybean meal based diet containing 5.8 g/kg of COS with MW of 0 (control), 600 (Cs6), 1,200 (Cs12), 2,400 (Cs24), and 3,600 (Cs36) Da for 56 d. The birds in Cs36 group exhibited better overall (0-56 d) feed efficiency (P < 0.05). Both Cs24 and Cs36 feeding decreased (P < 0.05) the liver and abdominal fat but only Cs36 decreased (P < 0.05) the subcutaneous fat. In the Cs24 and Cs36 groups, there was an improvement in the meat quality as evidenced by a decrease (P < 0.05) in drip loss of breast muscle as compared with the control and Cs6 groups. The liver lipid catabolism was enhanced (P < 0.05) by the 2,400 Da and 3,600 Da COS caused by an increase in lipoprotein lipase activity and mRNA expression, which might also be the reason for the reduced carcass fat deposition. In conclusion, the 3,600 Da COS supplementation significantly improved the overall feed conversion ratio of indigenous yellow-feathered chickens. Both 2,400 Da and 3,600 Da COS were effective in reducing liver and abdominal fat deposition, decreasing drip loss of breast muscle and promoting liver fat catabolism. The study highlighted the importance of the chitosan oligosaccharide MW when added to chicken diets.