Characterization of embryonic oxygen consumption of two broiler chicken lines differing in body fat content

Abstract

Eggs of two broiler chicken lines differing in body fat content were incubated and oxygen consumption of single embryos was measured on days 14–19 of incubation with an indirect calorimeter. The objectives of this study were to investigate oxygen consumption patterns of the two genetic lines in the late stage of embryonic development (days 14–19) and the relationship between this pattern and body composition of the bird at 8 wk of age. Oxygen consumption for the genetically lean line (LL) was higher (P < 0.05) than that for the genetically fat line (FL) for days 14 and 15 of incubation, while no differences were detectable after day 16 of incubation. The average oxygen consumption over the 6 d of measurement tended to be higher (P = 0.09) for LL than for FL. Furthermore, male embryos had a higher (P < 0.05) O2 consumption rate after day 17 of incubation than female embryos. The average O2 consumption rate over the 6 d of measurement tended to be higher (P = 0.07) for males than for females across genetic lines. At 8 wk of age, FL birds had greater (P < 0.01) body fat content than LL birds. Also, females showed a greater body fat content than males. Statistical analysis indicated that body fat content and body weight at 8-wk of age were correlated with embryonic O2 consumption. However, the correlation between body weight and embryonic O2 consumption was higher than that between body fat content and embryonic O2 consumption, which would be expected since oxygen consumption reflects lean body mass. Key words: Oxygen consumption, embryo, broiler, fat content, indirect calorimetry