Food intake controls in the suckling pig: glucoprivation and gastrointestinal factors

The energy balance of suckling Yorkshire pigs 1 day to 2 wk old was challenged by: food deprivation, glucoprivation, and caloric and noncaloric gastric loads delivered by intubation. tafter 2--4 h fasts, food intake greatly increased over nonfasted control intake during a 3-h refeeding period. This response occurred both when body weight gain was used as a measure of intake for pigs nursing on the sow and when intake was measured directly in bottle-fed pigs. Glucoprivation produced by 0.5--2 U/kg insulin did not stimulate food intake although plasma glucose fell to a mean of 49 mg/100 ml (43% of control) after 1 U/kg insulin. Gastric loads of water or 3% NACl depressed intake after 3-h fast, but 0.9% NaCl did not. All the caloric gastric loads depressed intake; in order of increasing effectiveness, they were: heavy cream, protein hydrolysate, corn oil, milk, 5% glucose, and 5% lactose. The carbohydrate loads were most effective, a result which indicates that the response was not to calories alone but to some specific nutrient, possibly glucose.