Author : Yuthana Siriwathananukul

Summary : Two feeding experiments and one digestion trial were conducted to evaluate the effect of lysine, methionine, threonine, and tryptophan supplementation to high copra meal diets on the growth performance and carcass characteristics of hogs and the nutrient digestibility of the rations. In the first feeding experiment, 36 barrows averaging 18 kg were randomly distributed to six dietary treatments composed of corn-soy diet as positive control and treatment groups of 40% copra meal diet supplemented without (C) and with lysine and methionine (CLM); lysine, methionine and threonine (CLMTh) or tryptophan (CLMT) and all four amino acids (CLMThT). The digestion trial involved 21 barrows averaging 24 kg liveweight randomly allotted to six dietary treatments of Experiment 1 plus a seventh ration composed of 40% copra meal diet containing lysine, methionine plus cystine, threonine, and tryptophan content at levels 105% of those found in corn-soy diet (hi-CLMThT). During the finishing stage 30 pigs weighing 75 kg were used to study the nutrient digestibility to six finisher rations of Experiment 1. The last feeding trial involved 16 barrows weighing initially 28 kg. The pigs were randomly allotted into two dietary treatments composed of a corn-soy diet and a 40% copra meal diet containing 105% lysine, methionine plus cystine, threonine and tryptophan content of corn-soy diet (hi-CLMThT). All animals of Experiment I and six pigs of Experiment 3 were slaughtered for carcass evaluation when the animals reached 95 and 90 kg liveweight, respectively. Results showed that supplementation of the four amino acids to copra meal diet improved the average daily gain, feed conversion ratio, length of feeding days and loin eye area by 26.8, 20.2, 21.0 and 21.0 percent, respectively, over the negative control (C diet) and were significant better than the other copra meal diets supplemented with only two (CLM) or three amino acids (CLMTh and CLMT).