Method: effect of different ileal content collection methods on ileal amino acid digestibility coefficients determination in broiler chickens

Abstract

This study compared two collection methods (CMs) to obtain ileal content from broiler chickens to determine apparent ileal amino acid digestibility coefficients (AIAAD). CM1 consisted of collecting the digesta by gently squeezing the ileum, while in CM2, the ileal digesta was flushed with distilled water. A total of 130 one-day-old male chicks were randomly distributed among 10 cages, using five replicate cages per CM. Birds were fed ad libitum with a standard starter diet from 0 to 18 d of age. At 18d, the diet switched to a corn-based semi-purified diet with 0.5% titanium dioxide (TiO2) as the indigestible marker. At 21d, birds were euthanized, and ileal digesta was collected using one of the two CMs. Bird performance was monitored; feed and lyophilized ileum content samples were analyzed to determine amino acids (AAs) and Ti content to determine AIAAD. A two-sided T-test and an F-test two-sided were performed to determine differences among the CMs’ means and variances, respectively. All significant differences were considered at a P-value < 0.05. Bird performance was similar for both groups throughout the experiment (P > 0.05). No significant differences between CMs were observed in the AIAAD coefficients for any of the amino acids analyzed (P < 0.05). The variances were significantly different for 6 AA (Iso, Lys, Thr, Ala, Asp, Glu; P < 0.05). In addition, four AAs approach significance (Leu, Met, Val, Pro; P < 0.1). The numeric values of the AAs variances were consistently higher when the sample was obtained using CM1. Squeezing may increase variability by enhancing endogenous losses like sloughed cells and mucin, underestimating digestibility in some samples. Using CM2 (flushing with distilled water) would provide more consistent and uniform results. This approach not only diminishes the likelihood of errors but also contributes to the standardization of methodologies applied in digestibility trials within the poultry research field.