The effects of dietary glycerol on growth and laying performance, egg traits and some blood biochemical parameters in quails

This study was designed to investigate the effects of different closes of glycerol from biodiesel production added to diets oil growth and laying performance, egg traits and some blood biochemical parameters in laying quails. A total of 425 (Coturnix coturnix japonica) quails, 10 weeks old, were randomly allotted into 5 groups of 85 birds each and glycerol was administered at the doses of 0 (control group), 25, 50 75 and 100 g/kg of diets during the 18 weeks long experimental period. The dietary glycerol treatment has not increased the mortality rate and has not significantly affected the growth and the laying parameters (body weight gain. food Consumption and efficiency. egg production aid weight). Only the highest glycerol dose has significantly altered the egg quality by decreasing the albumen height, the albumen index and the Haugh unit (P < 0.001) and increasing the yolk cholesterol content (P < 0.05). Furthermore. even if only a significant decrease of the stearic acid was evidenced (P < 0.05), the yolk composition in fatty acids appeared to he relatively modified with slight increases of sonic minor saturated acids, of the 2 monounsaturated C16:1 and C18:1 acids and of all polyunsaturated acids and decreases of the majority of monounsaturated acids, Under glycerol supplementation. In addition, except for the lowest dose, the serum triglyceride concentrations were significantly depressed (P < 0.001) and the serum ALT activities were also significantly reduced (P < 0.001) in birds receiving 50 or 100 g/kg glycerol in diets. These results suggest that. contrary to the highest dose, glycerol up to 75 g/kg in diets did not adversely affect the performance of laying quails and the egg quality and would be used as an alternative energy source.