Abstract
OBJECTIVE: The objective of this study was to investigate the effects of different degrees of maternal dietary energy restriction on lipid deposition in embryonic tissues during the medium laying period (37 to 39 weeks) in Arbor Acres (AA) broiler breeders. METHODS: A single factor design was adopted, and 400 AA broiler breeders (20 weeks of age) with a similar weight were randomly allocated into four groups. The birds in the control group were fed a corn-soybean meal based diet, and those in trial groups were fed diets with 80%, 70%, and 50% energy levels of the basal diet. Incubated eggs from the medium laying period were collected. Samples of developing embryos at various stages were prepared for composition analysis. RESULTS: The embryo weight in the 80% energy group was higher than those of the other groups on embryonic day (E) 13, but at 21 E, they were significantly decreased with decreasing energy intake of the broiler breeders (p<0.05). Additionally, the levels of crude fat in tissues in the restriction groups were significantly decreased (p<0.05). The long axis and area of adipocytes in breast muscle, thigh muscle and the liver were significantly decreased (p<0.05) at 21 E in the 80%, 70%, and 50% energy groups. CONCLUSION: The effects of the 80% maternal dietary energy restriction energy affects egg production performance, egg quality, and nutrient deposition in egg weights, which then directly impacts on the developmental process of embryos, especially on fat utilization and deposition.