Hatchability and embryonic mortality of Japanese quails as influenced by strain, egg shell -quality and storage length

Hatchability and embryonic mortality of two growth-selected lines of Japanese quails, as influenced by egg specific gravity (1.078 to 1.10 units) and pre-incubation storage length (0-11d) were studied based on 2374 incubated eggs. Data were analyzed on percentage and arcsin scales. Analysis of variance conducted to study the effect of strain, shell quality and storage length yielded similar results on the percentage as well as the arcsin transformed scales. Hatchability and incubation mortality were not affected by strain and egg specific gravity but were significantly influenced by storage length. Each day of storage for the entire period of 11 days decreased hatchability by 8.0 to 10.3%. The decline in hatchability resulted from increased in early (0-11d) mortality (b=9.38±1.21 and 11.2±1.10%/d). The linear terms of regression of hatchability and embryonic mortality on storage length accounted for 50 to 70% of the variation. The quadratic terms of regression were significant for hatchability of fertile eggs and early embryonic mortality but the contribution was low (2.7 to 15.7%). The curvilinearity resulted from a steep decline in hatchability beyond 7–8 days of storage where it virtually became zero.