The influence of the naked neck (Na) and frizzle (F) genes on performance and blood parameters of F2 and F3 generations of crosses of local and commercial chickens

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Two experiments were conducted in this study. In Experiment 1, a total of 1,565 eggs distributed in a randomized complete block design (RCBD) comprising 4 genotypes (treatments) and 15 hatches (blocks) were used. The eggs were produced from 33 F2 crossbred nanaff (normal feathered), Na (Naked neck), frizzle (F) and frizzle-naked neck chickens to determine their fertility and hatchability levels. The eggs were stored from one to seven days in a room at an average temperature of 26.060C. The Na, F and Na_F_ birds produced eggs of significantly (p<0.05) higher fertility levels compared to the nanaff genotypes. Hatchability (eggs set and fertile eggs) were significantly higher for the F_ birds than birds carrying the Na gene. One hundred and ninety-nine (199) F3 crossbred chickens obtained from six hatches generated by the F2 generation were used in Experiment 2 for the evaluation of growth, egg production, haematological and biochemical parameters. The genotypic groups were nanaff (normal feathered), NaNaff (homozygous naked neck), Nanaff (heterozygous naked neck), nanaFF (homozygous frizzle), nanaFf (heterozygous frizzle), NaNaFF (double homozygous frizzled-naked neck) and NanaFf (double heterozygous frizzled-naked neck). Feed and water were provided ad libitum. The Nanaff recorded a significantly (p<0.05) heavier day-old body weight compared to all other genotypes except the NaNaff ones. Generally, (p<0.05), body weight was lower in nanaFF, nanaFf and NaNaFF birds compared to other genotypes. The nanaff birds reached sexual maturity significantly earlier than all other genotypes. Hen day production and egg weight were also significantly (p<0.05) higher in nanaff birds compared to Na_, F_, and Na_F_ birds. All birds carrying the naked neck and frizzle gens had significantly (p<0.05) higher packed cell volume concentration than the nanaff birds. The Nanaff birds had a significantly higher Hb concentration compared to the nanaff, nanaFf and NaNaFF ones.
A Thesis submitted to the Department of Animal Science, College of Agriculture and Renewable Natural Resources in partial fulfilment of the requirements for the degree of Master of Science in Animal Breeding and Genetics