Growth performance, endocrine, and metabolite responses of finishing hogs to porcine prolactin

Prolactin, a member of the somatotropin-prolactin-placental lactogen gene family, increases feed intake and rate of weight gain in several species. To determine whether prolactin affects growth performance and carcass composition in swine, recombinant porcine prolactin (rpPRL) was administered to finishing hogs. Doses of 0, 2, 4, 8, and 16 mg of rpPRL/d and 4 mg of recombinant porcine somatotropin (rpST)/d were administered to groups of seven barrows and seven gilts initially weighing 75.0 +/- 2 kg for a 28-d period. Recombinant pPRL did not alter feed intake or growth rate or affect carcass composition. In addition, most growth-related blood variables did not change, although plasma IGF-I was increased in the 8 and 16 mg of rpPRL treatment groups. At slaughter, mammary development was apparent in rpPRL-treated gilts and was characterized by distended alveolar and ductal lumina and presence of secretory material. In rPST-treated hogs, feed intake was decreased 28% (P 0.01), gain/feed was increased more in barrows than in gilts (59 vs 39%, treatment X sex interaction, P