Ileal digestibility of amino acids in pig feeds and its use in diet formulations

The effects of four protein sources (soybean meal, sunflower meal, pea and fish meal as the main protein source) were investigated on fattening performance, carcass and meat quality traits and body composition of pigs. Eight animals per treatment received the diets from 30 to 105 kg live weight at a level of 3.0 times maintenance requirement of energy. Diets were formulated on the basis of ileal digestible protein and amino acid content of feedstuffs. Protein sources resulted similar fattening performance from 30-105 kg body weight. From 30 to 60 kg soybean treatment had lowest performance. The protein source treatments did not alter the body composition, lean meat percentage, liver weight and meat quality (intramuscular fat content, pH 45 min and 24 hours after slaughter, drip loss, meat lightness and hue measured 24 hours and 4 days after slaughter). It can be concluded that protein sources can be replaced without affecting overall fattening performance, carcass and meat quality and body composition if diet formulation is based on the ileal digestible amino acid contents of feedstuffs. However the lower performance of the soybean treatment in the first phase may indicate that ileal digestible Lys content of heat treated protein sources may not characterise the feedstuffs well enough. It may be that young pigs are more sensitive to unavailable lysine by the way.