Influence of In Ovo Leptin Injection into Yolk Sac on Embryo Development, Blood Biochemical Parameters and Lipid Metabolism of Broiler Chicks during Early Post-Hatching Period

Abstract

The study aimed to investigate the effect of in ovo (IO) leptin injection on yolk sac leptin concentration, embryo development, blood lipid metabolism, and biochemical parameters of broiler chicks during the early post-hatching period. Hatching eggs were weighed and placed in an incubator with 100 eggs/4 replications/group. The groups were: non-injected group (C); and 3 injected groups with 100 μl of phosphate buffer solution (PBS); 0.5 μl leptin (L0.5), and 1 μl leptin (L1) in 100 μl of PBS. Pure leptin hormone dissolved in PBS was injected into the yolk sac on day 7 of incubation. Yolk/yolk sac leptin concentrations at the onset of incubation, on days 7 and 15 of incubation, and at hatching were determined. Embryo/chick development was determined at all ages. Serum leptin, tri-iodothyronine (T3), thyroxine (T4), creatine kinase, total protein, uric acid, and lipid profiles were measured at hatching and day 7 of chick age. The leptin level of the yolk was similar to the leptin level of the yolk sac at hatching. Leptin level of a yolk sac was higher on 7th day than at other ages. IO injection* age was significant for serum leptin level, which was similar to one-day chicks in the L0.5 at day 7 of chick age. T3, T4, creatine kinase, uric acid, lipid profiles, and embryo/chick development did not change with IO leptin. Serum HDL level was higher in the leptin groups than C and PBS groups at hatching. IO leptin application affects blood lipid metabolism depending on dose level for male broiler chicks at the early post-hatch period, without affecting embryo/chick development.Leptin level of yolk was similar to leptin level of yolk sac at hatching. Leptin level of yolk sac was higher on 7th day than other ages. IO injection* age was significant for serum leptin level, which was similar to one-day chicks in the L0.5 at day 7 of chick age. T3, T4, creatine kinase, uric acid, lipid profiles, and embryo/chick development did not change with IO leptin. Serum HDL level was higher in the leptin groups than C and PBS groups at hatching. IO leptin application affects blood lipid metabolism depending on dose level for male broiler chicks at early post-hatch period, without affecting embryo/chick development.