Metabolizable energy requirement for starting barrow pigs (15 to 30 kg) fed on the ideal protein concept based diets

Abstract

The objective of this study was to determine the metabolizable energy (ME) requirement for starting barrow pigs. Forty-three animals, selected for their high lean gain, were allotted in a completely randomized block design, divided in four treatments with five blocks and two animals in each experimental unit. The diet in Treatment 1 consisted of 3,264 kcal of ME/kg containing 0.96% of digestible lysine, 0.55% of digestible methionine+cystine, 0.60% of digestible threonine, and 0.188% of digestible tryptophan reaching the ideal protein pattern. The diets in Treatments 2, 3, and 4 were similar to the diet in Treatment 1; nevertheless, the levels of ME in Treatments 2, 3, and 4 were 2, 4, and 6% higher than those in Treatment 1. The lysine:ME ratio, was mantained the same (2.82 g) in all treatments. The daily feed intake (DFI) and the feed:gain ratio (F:G) were not affected by the levels of ME. There was a linear increase of daily weight gain (DWG) and of daily energy intake (DEI). Later, a linear reduction in carcass protein percentage (CPP) and a linear increase of fat content and daily fat accretion (DFA) occurred. Results suggested that the required ME was of 3,264 kcal/kg or less for improved barrows (15 to 30 kg), of the dam line, fed with diets containing 0.96% of digestible lysine, formulated according to the ideal protein concept.