Morphometric parameters of chicken eggs depending on the intensity and direction of selection using the example of two gene pool breeds

The objective of this study was to analyze the key morphometric parameters of eggs from Russian White (egg) and Amrox (egg and meat) hens, which differ in their selection process.

Materials and Methods. The study was conducted on 34-week-old hens of the Russian White (n=26) and Amrox (n=22) gene pool breeds. The birds were housed in individual cages according to the farm's standard feeding and housing practices. The hens were evaluated for the following parameters on at least three consecutively laid eggs: egg weight (g), yolk size (g, %), PPF (º), elastic deformation (ED), and shape index (SI). Blood was collected from the axillary vein. The following parameters were determined: triglycerides (mmol/L), glucose (mmol/L), total cholesterol (mmol/L), creatinine (μmol/L), and total protein (g/L).

Results. Significant interbreed differences (p<0,001) were found in egg weight, shape index, protein fraction density index (PFD), and relative yolk size. Although Amrox chickens lay smaller eggs (egg weight is 10 % lower), their absolute and relative yolk content is higher than that of Russian Snow White chickens (by 4–6 %), which is also indirectly evidenced by a lower PFD value (by 4 %) and a higher PFD (+20 %). Blood biochemistry also revealed interbreed differences in the direction of metabolic processes in the poultry body. Thus, Amrox chickens have a 37 % higher (P<0.001) blood creatinine content and a 7 % lower total protein content compared to Russian Snow White chickens. The obtained data indicate that as a result of selection work on egg productivity indicators in Russian Snow White chickens, there was a significant decrease in the proportion of yolk in the egg.

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