DIVERGENT CONCENTRATIONS OF PLASMA METABOLITES IN SWINE SELECTED FOR 7 GENERATIONS FOR HIGH OR LOW PLASMA TOTAL CHOLESTEROL

It was reported previously that selection for high (HG) or low (LG) pl asma total cholesterol (TC) at 8 wk of age in a composite four-breed s wine population resulted after four generations in divergent mean conc entrations in the selected lines. The data revealed a significant posi tive correlation between body weight (BW) and TC concentration at 8 wk of age and differential responses in litter size, backfat depth, and carcass length at 6 mo of age. We report here the relationship between plasma TC concentration and other plasma traits related to growth and metabolism in the seventh generation of selection in these two lines of pigs. We measured plasma concentrations of TC, HDL cholesterol (HDL C), triglycerides (TG), alkaline phosphatase (ALP), total protein (TP) , albumin (ALE), urea nitrogen (urea N), and three transaminases (alan ine aminotransferase, ALT; aspartate aminotransferase, AST; gamma glut amyltransferase, GGT) in seventh-generation male and female pigs at 8 wk of age. Birth weight (1.48 vs 1.38 kg), 8 wk BW (14.85 vs 12.00 kg) , TC (116.8 vs 63.6 mg/dL), HDL-C (43.9 vs 25.5 mg/dL), TG (50.5 vs 33 .0 mg/dL), and ALP (78.3 vs 44.9 units/L) were higher (P < .01) in HG than in LG pigs, whereas ALE (3.2 vs 3.4 g/dL), ALT (43.0 vs 45.9 unit s/L), and AST (53.0 vs 62.2 units/L) were lower in HG than in LG pigs (P < .05). At 8 wk, overall plasma TC concentration was correlated wit h BW (r = .34, P < .01) and with ALP (r = .23, P < .05) but was not re lated to ALT, AST, or GGT. Plasma TP, urea N, and GGT were unaffected by genetic line or sex. We conclude that the difference between HG and LG pigs in TC concentration in generation 4 at 8 wk of age has persis ted but not broadened in pigs of generation 7, that changes in plasma ALP, ALT, and AST may have occurred in, response to selection for high or low plasma TC, and that ALP is correlated with plasma TC concentra tion.