AMINO ACIDS DIGESTIBILITY TO PIGS IN VARIOUS FIBER SOURCES : 1. APPARENT DIGESTIBILITY OF AMINO ACIDS IN ILEAL DIGESTA AND FECES

Four fibrous feedstuffs from alfalfa meal (AFM), cassava leaf meal (CLM), rubber seed meal (RSM) and leucaena meal (LM) were included in semi-purified diets for growing pig (45 kg body wt.) at 20%, to investigate the effects of these fiber sources and fractions on amino acid digestibility. Cellulose (C), a purified fiber source was included in another diet at 5% level for comparison. The barrows fitted with ileal T-cannula were used in the digestion trials with latin square design. The digestibilities of amino acids were measured at both terminal ileum and fecal level. NDF and hemicellulose content were the highest in AFM-diet whereas LM-diet had the highest ADF and lignin content. RSM-diet contained the highest crude fiber and cellulose content. The digestibilities of amino acids at ileal level were found the highest with CLM-diet, while LM-diet was the least. At fecal level, control diet and CLM-diet were the highest in amino acid digestibility while AFM-diet was the least. The digestibility of amino acids was higher at ileal than fecal level. The digestibility of arginine was not affected with fiber fractions but was found to be the most disestible across all diets. The most depressed amino acid was methionine at both levels; praline and glycine, in the dispensable amino acid group, were depressed at ileal and fecal level, respectively. Lignin did not depress amino acid digestibility in general but specifically depressed methionine, histidine, isoleucine and threonine digestibility. Cellulose content did not affect amino acid digestibility but undesirable factors might be responsible.