Determination of amino acid digestibility with different methods in birds. A comperative study

Abstract

A comparative study was conducted with layer hens either intact, or cecectomized or cannulated in the ileum or colon to determine the amino acid digestibility of the same diet. The studies used Shaver Star Cross 288 layer hybrids, with 6 birds per each test method, in 2 replicates (n=12). Birds were placed in metabolic cages during the studies. Nutrient content of the trial diets followed the NRC (1994) recommendations. Amino acid content of the diet, excreta, faeces and digesta samples was determined according to Bech et al (1990). Trial data were subjected to variance analysis (ANOVA) (SAS 2001). The trial data led to the conclusion, that no statistically verifiable differences (Pł0.05) could be found between the amino acid digestibilities of intact or cecectomized birds. Neither was a statistically verifiable difference (Pł0.05) found between the amino acid digestibilities measured at the terminal ileum or terminal colon. The digestibility values found with intact and cecectomized birds, however, were significantly lower (PŁ0.05) than the digestibility measured at the terminal ileum or terminal colon. Also these trial data lead to the conclusion - in accordance with the relevant data in literature - that diet formulations should be based on the digestible amino acid content in poultry nutrition as well. In contrast to what was found for pigs, however, there is no difference in whether we use faecal or ileal digestibility in the formulation of poultry diets.