Two-Way Selection for Serum Alkaline Phosphatase in Laying Hens

Abstract

The effectiveness of two way selection for serum alkaline phosphatase (S.A.P.) was investigated to determine its influence on productive traits in a White Leghorn population for three generations. The difference between females in the high and low lines at the end of three generations was S3 percent of the S.A.P. level of the foundation population. Selection was based entirely on phenotypic differences. The divergence of the lines was significant and greater in the high line. Computed heritabilities from within sire dam offspring regression for S.A.P. was .42. Heritability estimates from the analysis of variance sire component was .12 ± .09, and from the dam component .76 ± .16. The realized heritability was .45 and .36 for high and low lines respectively.No correlated responses were found during the time of this study for hen day egg production, egg weight, specific gravity or mortality. Hatchability decreased significantly in the high line and fertility decreased significantly in the low line.A build up of phosphatase in the blood occurred during the formation of the egg which would be an indication that the enzyme is involved in egg shell formation.

Biochemical blood parameters in pigs

“…Several reports suggest that plasma AP levels are associated with the growth rate in animals (C ombs et al 1959; W ilcox 1966; C houdhary et al 1971; Y amaki and M izuma 1982; S ingh et al 1983; D oornenbal et al 1986). In the present study the estimate of heritability for AP was close to 20%, which is lower than the corresponding realized heritabilities found in mice (Y amaki and M izuma (1982) and in the laying hens (M c C lung et al 1972). The heritability estimates based on sire variance components in the latter study were, however, lower than that estimated in the present study.…”

Blood Composition of Different Beef Breed Types

“…Blood components are related to fertility, growth and body composition in cattle (Blum et al 1983; Land et al 1983;Rowlands et al 1983). Selection experiments designed to change some blood components in poultry (McClung et al 1972) and mice (Tilakaratne et al 198 I ; Yamaki and Mizuma 1982) have been successful.…”