Digestible indispensable amino acid score and digestible amino acids in eight cereal grains

To determine values for the digestible indispensable amino acid score (DIAAS), it is recommended that ileal amino acid (AA) digestibility values obtained in growing pigs are used to characterise protein quality in different foods. Therefore, an experiment was conducted to determine the standardised ileal digestibility (SID) of AA in eight cereal grains (yellow dent maize, Nutridense maize, dehulled barley, dehulled oats, polished white rice, rye, sorghum and wheat) fed to pigs, where SID values in pigs can be used to calculate approximate DIAAS values in humans. In the present experiment, twenty-four barrows with a T-cannula inserted in the distal ileum were allotted to eight diets and fed for three periods to give a total of nine replicate pigs per diet. Each period lasted 14d, and ileal digesta samples were collected on days 13 and 14. Among the SID values obtained for all cereal grains, values for total indispensable AA were greatest (P<0 center dot 05) in rice and lowest (P<0 center dot 05) in rye and sorghum. The concentrations of SID indispensable AA in rice were less (P<0 center dot 05) than in dehulled oats, but greater (P<0 center dot 05) than in the other cereal grains, and the concentrations of SID indispensable AA in Nutridense maize were greater (P<0 center dot 05) than in yellow dent maize and sorghum, but less (P<0 center dot 05) than in the other cereal grains, except rye. In conclusion, results indicate that to meet dietary requirements for AA in humans, diets based on yellow dent maize or sorghum require more AA supplementation than diets based on other cereal grains.