Influence of C locus alleles on neonatal development in the domestic fowl

Neonatal development, as influenced by the autosomal albino (ca/ca), recessive white (c/ca), or colored (C+/-) genotype, was investigated. Albino chicks exhibited smaller (P less than or equal to .005) body weights at 3, 6, and 9 days of age. A significant (P less than or equal to .005) reduction in growth rate also occurred in albinos from hatching to 3 days of age. Associated with the suppression of growth was the retention of greater (P less than or equal to .05) amounts of yolk sac contents. Albino chicks exhibited smaller (P less than or equal to .01) bursal weights at hatching and 6 days of age. Plasma glucose and protein levels were depressed (P less than or equal to .005) in albinos at hatching when compared to recessive white or colored chicks. No significant differences in plasma glucose or protein were noted at any other time periods. These data provide evidence for the retardation of neonatal development and a reduction in maternal yolk utilization by the ca/ca embryo. We suggest that there may exist additional physiological functions for melanin/functional tyrosinase that are not directly involved with pigmentation.