PLASMA CHOLECYSTOKININ-8 IN PIGS WITH DIVERGENT GENETIC POTENTIAL FORFEED-INTAKE AND GROWTH

Plasma cholecystokinin-8 (CCK-8) was studied in pigs with divergent ge netic potential for feed intake. Differences in feed intake resulted f rom selection for either fast (line Fl or slow (line S) postweaning ga in. The hypothesis was that the relatively lesser feed intake in S ver sus F may be attributable, in part, to greater circulating concentrati ons of the putative satiety hormone CCK-8. In Experiment 1, barrows fr om F (n = 23) and S (ii = 19) were used to determine changes in CCK-8 associated with ad libitum feed consumption. Blood samples were collec ted after overnight feed deprivation, then periodically during a 2-hr feeding period. Averaged across sampling times, concentration of CCK-8 tended to be greater (P = 0.07) in S (6.70 pmol/l) than in F (5.06 pm ol/l). Concentration of CCK-8 per unit of feed consumed (CCK-8/cumulat ive feed intake) was greater (P < 0.01) in S than in F during the firs t 30 min of the feeding period. In Experiment 2, plasma concentrations were determined for nine pairs (F, S) of the same barrows allowed an amount of feed equal to the previous ad libitum intake of the S barrow in the pair. Averaged across times, the difference between CCK-8 conc entrations of S (11.65 pmol/l) and F (7.94 pmol/l) barrows was not sig nificant (P = 0.18). A greater concentration of CCK-8 per unit of feed consumed in S than in F supports the hypothesis that satiety effects of CCK-8 may play a role in genetic differences between the lines for feed intake. (C) Elsevier Science Inc. 1998.