Dietary factors involved in feed intake regulation in growing pigs: A review

The objective of the present review was to consider the dietary factors involved in the adjustment of voluntary feed or energy intake in the growing pig. Energy concentration was the primary factor to be taken into account, in relation to growth potential and lean-tissue gain as affected by age, sex and genotype, as well as climatic environment. The effect of protein level and amino acid balance on voluntary feed intake is reviewed in the second part of the paper, by considering the compensatory increase in feed consumption following a moderate deficiency in the limiting amino acid or total protein, and the performance benefit to be expected from correcting amino-acid excesses in common diets. Finally, the separate regulations of energy and protein intakes are analyzed through self-selection of two dietary portions with different protein-energy ratios. The results obtained are further evidence that protein intake is separately regulated from energy intake and that both controlling mechanisms interact in determining overall feed intake.