PSVIII-34 Late-Breaking Abstract: Additivity of digestible amino acids in hatchery byproducts fed to nursery pigs

Abstract

Abstract The objectives were to determine standardized ileal digestibility (SID) of amino acids (AA) in hatchery byproducts fed to nursery pigs and to test the additivity of ileal digestible AA concentrations in hatchery byproducts. Ten barrows (initial body weight = 11.3 ± 1.3 kg) surgically fitted with T-cannulas at the distal ileum were individually housed in pens. Four diets were prepared to contain 30% of infertile eggs, unhatched eggs, culled chicks, or a mixture (20% dried infertile eggs + 20% dried unhatched eggs + 60% dried culled chicks) as the sole source of nitrogen. A nitrogen-free diet was additionally prepared to measure basal endogenous losses of AA. All experimental diet contained 0.5% chromic oxide as an indigestible index. Ten pigs were assigned to a replicated 5 × 4 Latin square design with 5 diets and 4 periods. Each period consisted of a 5-d adaptation period and a 2-d collection period. The hypothesis was that the determined digestible AA concentrations of the mixture are not different from the calculated values based on digestible AA in the individual ingredients. A t-test was used to determine the additivity of digestible AA concentrations in individual ingredients. Infertile eggs had greater (P < 0.05) SID of all indispensable AA except for lysine and methionine compared with culled chicks. The SID of all indispensable AA except for tryptophan was not different between culled chicks and the mixture. The calculated apparent and standardized ileal digestible AA in the mixture were not different from the determined values, but calculated ileal digestible tryptophan in the mixture was less (P < 0.05) than the measured value. In conclusion, ileal digestibility of most indispensable AA in infertile eggs is greater than that in culled chicks and ileal digestible AA values are additive in the mixture except for tryptophan.