DIETARY-FAT AND CHOLESTEROL IN YOUNG-ADULT BOARS GENETICALLY SELECTEDFOR HIGH OR LOW PLASMA-CHOLESTEROL - RESPONSE

Twenty-eight young adult boars (age 7 to 8 mo) genetically selected fo r four generations for high (HG) or low (LG) plasma cholesterol were s tudied to assess dietary and genetic effects and their interactions on cholesterol metabolism. Boars within a genetic group were paired acco rding to their plasma ne cholesterol concentration at 8 wk of age and were fed for 15 wk (2.7 kg/d) one of two diets (16.5% fat and 1,156 mg of cholesterol/kg diet, HD; or 3.1% fat and O cholesterol diet, LD) i n a 2 x 2 factorial arrangement. Plasma total cholesterol (P <.01) and HDL-cholesterol (P <.01) concentrations were higher in boars fed HS ( P <.01) and in HG boars (P <.01). There was a trend toward a diet x ge notype interaction for plasma HDL-cholesterol (P <.06). Plasma insulin concentration tended to be lower in boars fed HD (P <.09) or HG boars (P <.10). There was a diet X genotype interaction for plasma glucagon (P <.04) concentration and a trend toward an interaction for insulin (P <.07). After 15 wk, all boars were killed by electrocution and exsa nguination and measurements were taken. Backfat thickness was greater (P <.01) and carcass length (P <.01) and weight's of the four lean cut s (P <.02) were lower in LG than in HG boars. No microscopic atheroscl erotic plaques were observed in aorta or coronary arteries. Cholestero l concentration in subcutaneous fat was lower (P <.04) in LG boars, su ggesting that cholesterol content of depot fat can be reduced by genet ic selection in swine.