Effect of Genotype and Holding Duration on Some Post-Hatch Traits of Day-Old Broiler Pure Line Chicks

Abstract

In this study, it was aimed to investigate the effects of varying holding durations on some post-hatching characteristics of broiler pure line chicks with different selection backgrounds. Fifty d-old chicks from each of 3 dam (A1, A2, A3) and 1 sire (B1) ANADOLU-T broiler pure lines were used. Ten chicks of each genotype were treated with holding durations of 0, 12, 24, 36 and 48-h after hatching. At the end of each holding duration, individual chick weight (g), weight loss (g, %), chick length (mm), wing feather length (mm), rectal temperature (°C), yolk sac weight and percentage (g, %) and yolk-free body mass (g) were determined. Hatching egg weights were similar in A1 (60.9 g), A2 (60.9 g) and B1 (61.1 g) lines, but higher than A3 (59.2 g) (P<0.001). Chick weights were significantly different between genotypes both at hatch and at the each holding duration (P<0.01) and B1 line chicks were the heaviest, A3 the lightest. Absolute and relative mean weight loss occurred in the A3, B1, A1 and A2 lines as 3.7 g and 8.6%, 3.6 g and 8.8%, 3.0 g and 7.3% and 3.1 g and 7.2%, respectively (P<0.01). While the chick length increased linearly as the holding duration progressed in the B1 and A2 lines, it decreased after the 12-h holding period in the A1 line chicks (Interaction effect, P=0.026). The A1 (11.1 mm) and A3 (9.8 mm) line chicks had significantly shorter wing feather lengths (P<0.001) than A2 (15.4 mm) and B1 (15.1 mm) chicks. Rectal temperature values were lower in the A1 line than the others (P<0.01). Genotype x holding duration interaction on yolk sac weight and percentage was significant (P<0.05). A3 chicks with the highest yolk sac weight (6.2 g) and percentage (15.2%) at hatch had higher yellow sac absorption than other genotypes during the 48-h holding. Yolk-free body mass was the highest in B1 (36.7 g) and lowest in A3 chicks (34.5 g) (P<0.001). In conclusion, chick weight, chick length and yolk-free body mass were greatly influenced by egg weight. Regardless of the genotype, the extended holding durations at hatch resulted in deterioration in the general chick characteristics. Further studies are needed to reveal embryonic development and early post-hatch chick characteristics that are likely altered by different selection strategies for each pure line.