Motivational influences underlying prolactin-induced feeding in doves (Streptopelia risoria)

Prolactin (Prl) increases food consumption in ring doves (Streptopelia riso ria) and may promote the hyperphagia exhibited by parent doves when provisi oning young. These experiments tested whether Prl also enhances appetitive aspects of feeding behavior. Prl elevated pecking rates in food-restricted doves on a variable-interval (VI) reinforcement schedule and supported cont inued responding when doves were returned to ad-lib feeding. Prl-treated do ves learned the key-pecking response when food intake was clamped at ad-lib levels exhibited before Prl treatment but not when given free access to fo od. Median break points on a progressive ratio schedule were 2-3 rimes grea ter in food-restricted doves than Prl-treated, food-clamped doves even thou gh response rates were similar on VI schedules. These results indicate that Prl enhances appetitive aspects of feeding, although food restriction at t he level imposed in this study was more effective in this regard.