Abstract

OBANLA, L.O. et al. Nutrient utilization during incubation and juvenile growth of indigenous and exotic chicken in Nigeria. Arch. zootec. [online]. 2014, vol.63, n.242, pp.251-258. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922014000200003.

Nutrient utilization and early growth rate in three strains of chicken were investigated using 900 hatching eggs, 300 from each strain. The strains of chicken used were Nigerian indigenous chicken (NIC), ISA Brown (IB) and Nera Black strains (NB). Ten eggs per strain were randomly selected for breakout at embryonic day (ED) 7, 11, 15, and 18 of incubation to collect data on albumen weight in order to determine the embryonic albumen reduction rate during incubation and yolk weight to monitor its utilization. Blood samples were collected at hatch (day-old), weeks 1, 2, 3 and 4 post-hatch for triiodothyronine (T₃), thyroxine (T₄) and corticosterone level (CORT) determination. The chicks were randomly distributed into four rearing pens for a 28-day assessment of growth rate. The results showed that at day 18 of incubation (ED 18), weight of egg yolk and rate of yolk loss were similar among all the strains. Also, from ED 0 to 7 and11 to 15, albumen reduction rate in the eggs of IB was higher compared to NB and NIC, while it was lowest in NIC. From ED7 to 11, NIC showed highest reduction rate, followed by NB. Lowest reduction rate was shown in the eggs of IB. At day 7 and 28 of post-hatch growth, relative weight gain by the NIC was higher compared to NB and IB chicks. While IB and NB strains were similar at day 7, NB showed an intermediate relative weight gain at day 28. Strain did not significantly (p>0.05) affect body weight at all the ages. At day 14 and 21 of post-hatch growth, strain did not affect relative weight gain except at day 7 and 28. At day 7 and 28 relative weight gain by the NIC chicks was higher compared to NB and IB chicks. While IB and NB were similar at day 7, NB showed an intermediate relative weight gain at day 28. Plasma CORT level did not change from day-old until day 28 in all strains. Similarly, CORT levels did not differ among strains at each age of determination. T₃ concentration increased from day-old until day 7 post-hatch and leveled out throughout the ages of observation in all the strains. The weight differences of the embryos at ED18 and day-old-chicks at the hatching day suggest the influence of genetic differences and possibly that of inadequate incubation protocol at this stage.

Keywords : Hormones.

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