Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 2. Correlated responses in plasma lipoproteins and lipids.

Lipoproteins from generations five and six of Japanese quail (Coturnix coturnix japonica) divergently selected for increased (HW) or decreased (LW) body weight at 4 weeks of age or increased (HP) or decreased (LP) plasma yolk precursor at the initiation of egg production were separated into fractions of d less than 1.006 and d greater than 1.006. A randombred control (R1) was also sampled. Total lipids (TL), neutral lipids (NL), and phospholipids (PL) were determined. The NL's of the d less than 1.006 lipoprotein fractions were also analyzed for cholesterol esters (CE), triglycerides (TG), cholesterol (C), and a fraction of minor lipid components including digycerides (DG+). A correlation of .960 between total plasma phosphorus and TL of the d less than 1.006 lipoprotein fraction was observed. No strain effect was noted for TL, NL, or PL for either generation in the d greater than 1.006 fraction. In the d less than 1.006 fraction, TL, NL, and PL all varied concurrently, with the order being HP greater than HW, LW, R1 greater than LP. Percent NL and PL did not vary with strain in the S5 generation in the d less than 1.006 fraction. In the S6, the HP strain had a higher % NL and lower % PL in the d less than 1.006 fraction. No differences in % NL and PL were noted for the d greater than 1.006 fraction. In the d less than 1.006 fraction all lipid classes in the NL's tended to vary together. It was concluded that selecting for total plasma phosphorus in laying female Japanese quail is effective in quantitatively but not qualitatively altering the d less than 1.006 lipoprotein levels in the laying hen plasma, without affecting the d greater than 1.006 lipoproteins levels. It was also concluded that selecting for body weight for six generations did not affect laying female lipoprotein concentration.