Morphological features of eggs depending on the chicken genotype by mutations T+3737C and A+3971G in insulin locus

Abstract

Quality of eggs, including morphological features, affect on their dietary properties, incubatory and trade characteristics. This gives background to affirm necessity of selection work in direction of improving these features additionally to chicken egg-laying qualities. But selection by complex of traits requires long time and significant resources. To increase effectiveness and speed up the process of selection molecular genetic markers are used. Such approach is named marker-assisted selection. One of genes, that is of interest in the context of marker-assisted selection, is insulin gene, which product takes part in the regulation of animal metabolism. The gene is polymorphic in chicken, particularly, there were found mutations T+3737C and A+3971G, located within second intron and 3'-UTR-region, respectively. The current work is devoted of studying of morphological features of eggs depending on the genotype by above-mentioned mutations. The research was conducted on the chicken population of line 38 of Rhode Island Red breed. The following features were studied as yolk weight, glair weight, shell weight, yolk percent, shell percent, mean shell thickness, egg form index. Measuring was made on 30th and 52th weeks of layer age. Comparison of groups with different genotypes was conducted using t-criterion or U-criterion depending on the distribution normality. There was no significant associations between genotype by T+3737C mutation and egg morphological features within investigated line. By mutation A+3971G it was shown, that eggs of layers with AA genotype differ significantly (P ≤ 0.05) from eggs that received from chickens with AG and GG genotypes by egg form index on 30th week. Also, significant (P ≤ 0.01) association was revealed for yolk percent on 52th week of life and genotype on this mutation. Namely, chickens with AA genotype layed eggs with lower yolk percent than chickens with AG and GG genotypes. Similar situation was observed relatively to yolk weight but difference was reliable (P ≤ 0.05) only between homozygotes AA and GG. According to the results, it is possible to consider mutation A+3971G as the molecular genetic marker of morphological features of chicken eggs.