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Abstract:
Superalimentation (SA) of swine at 120% (ad libitum = 100%) for 23 days elicited a 40% greater gain of body mass (P less than .005) than littermate control (C) pigs. The accretion of lean and fat tissues during this excess and rapid growth were about the same as if the animal were allowed to attain the same weight over a longer period by conventional feeding practices. Superalimentation is defined as feed intake distinctly in excess of normal voluntary intake on a grams-dry-matter-per-kilogram-body-weight basis. The substantial body mass response shows that growth is limited by a lack of nutrient intake (appetite) during normal ad libitum feeding. Either digestion-absorption processes are not saturated during normal feed intake or digestion and absorption capacities are enhanced during excess food intake; furthermore, either cellular hyperplasia or hypertrophy are not regulated by inherited neuroendocrine factors or cellular growth is somehow released from neuroendocrine regulation during periods of excess circulating nutrients. The overall gain efficiency (kg total gain per kg total alimentation dry matter) during superalimentation was slightly improved (7.3%) but was not significant. Efficiency of the differential gain (delta gain/delta dry matter intake; delta = SA-C) was 25% higher than the overall gain efficiency of the C pigs (0.374 vs 0.300 kg/kg) and suggests that the additional nutrients may have been utilized for growth with greater efficiency than nutrient consumed ad libitum.