Features of nitric oxide metabolism in embryos of different bird species as genetically determined sign associated with meat productivity

At present, the role of nitric oxide (NO) in embryogenesis, in particular in myogenesis, is widely discussed. Earlier we noted that the main part of nitric oxide synthesized in the avian embryo can accumulate in tissues as part of the so-called NO donor compounds or be oxidized to nitrate. The degree of this oxidation correlates with the meat productivity of adults. This report shows that in broiler embryos, NO is oxidized to nitrate by 90% or more, while in embryos of egg poultry NO oxidation is negligible. That is, the degree of NO oxidation is determined by some features of the embryo tissues rather than NO itself determines these features. Consequently, the degree of NO oxidation in bird embryogenesis is an indicator associated with tissue properties correlating with meat productivity. Since this sign is inherited, it is assumed to be genetically determined. The purpose of this work is to characterize the manifestation and inheritance of the intensity of nitric oxide oxidation and the associated physiological characteristics of embryos in birds of different species.The purpose of this work is to characterize the manifestation and inheritance of the intensity of nitric oxide oxidation and the associated physiological characteristics of bird embryos of different species. The experiments were carried out in a vivarium (Zagorskoye, Sergiev Posad, Moscow Province, 2015-2021). It was shown that in poultry of different breeds characterized by the same degree of NO oxidation the live weight can vary significantly. This is especially evident in hens. The proportion of oxidized NO in the embryo was higher in lines, breeds and crosses obtained as a result of breeding to increase meat productivity. Thus, in the embryos of broilers and meat quails, by the day 7th, more than 90% of embryonic NO is oxidized, in egg forms oxidation was insignificant (several percent), most meat-egg forms occupied an intermediate position according to this index. The analysis of inheritance of the index in the F1 generation in several bird species suggests that this trait is formed due to the expression of various genes that can both promote and counteract its manifestation. Oxidation of NO to nitrate in embryos of both meat and egg forms can be induced by light at the beginning of incubation. In embryos of egg forms, the proportion of oxidized NO can increase up to 60 % under the action of light. Consequently, there is a possibility of oxidation of NO in embryos of both meat and egg forms. Apparently, the mechanism of activation of this process is inherited, which can also be partially induced by light. Further analysis of the inheritance of the intensity of oxidation of embryonic NO in a number of generations will show which genes are associated with the intensity of oxidation of NO. This will allow using this indicator as a highly sensitive marker for the corresponding genes.