Resumo

EL-TAHAWY, W.S.  e  HABASHY, W.S.. Genetic effects on growth and egg production traits in two-way crosses of Egyptian and commercial layer chickens. S. Afr. j. anim. sci. [online]. 2021, vol.51, n.3, pp.349-354. ISSN 2221-4062.  http://dx.doi.org/10.4314/sajas.v51i3.8.

A crossbreeding experiment was conducted between the Sinai (SI), an indigenous Egyptian strain, and the exotic Lohmann Brown (LB) breeds of chickens. A total of 790 chicks were produced in four genetic groups, namely SI x SI, LB x LB, SI x LB, and LB x SI. The objective was to estimate the direct additive effect (gⁱ), individual heterosis (hⁱ), and maternal additive effect (g^m) for growth and reproduction traits. Direct additive effects were positive (P <0.01) for bodyweight (BW) at 4, 8, and 12 weeks old in favour of SI. For egg production traits, gⁱ was positive for age at sexual maturity (ASM) and age at which the first 10 eggs were produced (P10), but negative for mean 10 egg production (MP10), egg number at 90 days (EN90),mean egg number at 90 days (MEN90), and egg mass (EM). The estimates of heterosis (%) were high for BW and daily gain except for BW0. Maternal effect estimates of BW and daily weight gain were significant (P <0.05) only for bodyweight at hatching (BW0), bodyweight at 4 weeks old (BW4) and daily weight gain from four to eight weeks old (DWG4-8). Thus, the Sinai and Lohmann Brown crossbreed produced favourable heterosis on the growth of the chicks. As an adapted indigenous strain, SI should be regarded as a dam line in crossing with LB, which has greater genetic potential for growth. Use of LB as a sire strain in conjunction with Sinai would increase egg production from the resulting hybrid chickens.

Palavras-chave : crossing; direct effect; Egyptian Sinai; heterosis; Lohmann Brown; maternal effect.

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