Genetic Evaluation of the Impact of Mating Between Commercial Laying Hens (LSL) with Some Local Egyptian Strains Chicken and its Effects on Some Productive and Physiological Parameters

摘要

The objective of this study is to investigate the genetic similarity between hybrids and commercial strain chickens using random amplyphysim polymorphisem DNA ( RAPD-PCR ) marker, as well, to compare some productive and physiological traits. Locally developed strains of chickens (Silver Montazah (SM), Inshase (IN) and Matrouh (Mt)) with one commercial strain Lohman Selected Leghorn (LSL) were mated to produce the three way-crosses MtxLSLxSM and MtxLSLxIN. Results revealed that, Pullets of LSL strain matured earlier (151.3 day) than three way-crosses MtxLSLxSM and MtxLSLxIN (154.67 and 160.7 day), respectively. Crossbred MtxLSLxIN had superior annual egg production (172 eggs) than MtxLSLxSM (154 eggs). The LSL strain had the heaviest egg weight and egg mass means during the 52 weeks of production compared to the tow three way-crosses. Plasma Estrodiol 17- (E2) concentration of LSL strain was higher compared to the three local strains chickens. Increasing both of plasma E2 and E2/P4 ratios of LSL strain and crossbred chickens are correlated with higher egg production traits. Positive heterosis percentage for body weight at sexual maturity, annual egg number and annual egg mass of the 3-way cross were found while the age at sexual maturity, egg production traits during the 1st 90 days and annual egg weight had negative heterosis percentage. The genetic similarity among chicken hybrid and LSL parent was estimated as 37% between the 3-way cross (MtxLSLxSM) and LSL and 33% between the 3-way cross (MtxLSLxIN) and LSL strain based on RAPD-PCR . Generally, The three-way crosses improved age at sexual maturity and annual egg number, also, increased plasma E2 and P4 hormones concentration compared to the pure strain. The result of DNA analysis indicated that genetic similarity may coincide with percent heterosis and this result agreed with the results of economic traits and hormones analysis.