鸡蛋的品质及其遗传的研究

本文报告了白来航和洛岛红两个品种、五个品系及其十一个杂交组合的蛋质特性及其遗传特点。白来航鸡蛋质较好,存在不同程度的品系间及家系间差异。洛岛红鸡蛋壳质量较差。产蛋后期蛋壳质量显著下降。但洛岛红鸡表现出较强的钙沉积能力。本研究测定了蛋质性状的遗传力估计值,蛋壳质量遗传力较低,蛋白质量遗传力较高。产蛋量等经济性状与蛋质性状间的关系,除蛋重与蛋白质量为正相关外,均呈一定程度的负相关。蛋壳质量的杂交效应,白来航与洛岛红杂种鸡表现出杂种优势。蛋白质量无优势。蛋重和蛋白质量一般配合力高度显著,蛋壳质量特殊配合力显著。在近交系数为25%时,蛋质不表现近交衰退。

STUDIES ON THE EGG QUALITY AND ITS HERIDITY

This paper reported the results of experiments on the study of egg qualityand its genetic behaviors.Data were collected from 5 strains and 15 hybridcombinations produced by white Leghorns(W L)and Rhod Island Reds(R IR).Results obtained indicated that the egg quality of W L were superior,butthere were difference between lines and various families within the same line.Egg shell quality of R I R was inferior.Egg quality was affected significantlyby the age of hens.Shell quality and Hough unit declined notably in the laterstage of egg production,except for the R I R.Heritability estimate of egg weight in the present study was lower thanthose reported in previous literature,and it was lower for shell quality,andhigher for albumen hight and Haugh unit.Correlation coefficents obtainedindicated negative values between egg quality traits and egg production andegg and body weight,but possitive between egg weight and Haugh unit.Hybrid produced by reciprocal crossing W L with R I R breeds exhibitedheterosis in shell quality,but none between linecrosses within the W L.Results of reciprocal crosses suggested that the genetic pattern of egg weightand albumen quality was autosomal inheretance.It was found that the eggweight and Haugh unit exhibited highly Significant general combining ability(g.c.a.)and shell weight per unit surface area revealed specific combiningability(s.c.a.)besides being in highly significant g.c.a.The line E exhibitedthe highest g.c.a.for egg quality.Inbreeding depression for egg quality wasnot found with the inbreeding coefficent at 25 percent.As to on-farm selection for peformance of egg production,more selectionpressure should be given when selecting for economical important traits whilemaintaining the present merit of egg quality,and eliminating the inferior fa- milies and individuals.For R I R both shell quality and blood and meat spotsshould be improved.It was found that the association of egg weight,egg shape and shell tex-ture with shell strength was low,However,correlation index(R~2)between spe-cific gravity of egg and shell thickness with shell strength was 0.4296.Theseresults showed that specific gravity had higher predictive value for shell qua-lity because it is reliable and convenient in practice with indestruction of theintact egg.Sampling measurements on egg quality for a breeding farm should be madeat the early stage and again at the late stage of egg production.