The quantitative flow of basal endogenous losses of amino acids (AA) is used for the correction of apparent digestibility values of AA to derive their standardized ileal digestibility values. On the other hand, fat digestibility depends on their physical and chemical properties which in turn influence the digestibility of other dietary components, possibly including the AA flow. Therefore, this 21-d experiment investigated the effect of two fat types (tallow or soybean oil) on the amounts of basal endogenous AA losses, gut morphology of the small intestinal sections and cecal short-chain fatty acid (SCFA) profile. A total of 80 broiler chickens were allocated to two treatments consisting of two nitrogen-free diets in which the fat type used is either soybean oil (NFDS) or tallow (NFDT). Each treatment had eight replicates in a randomized complete block design with 5 birds per replicate. All the birds were fed a basal corn-soybean meal diet for 16 d and experimental diets from d 16 to 21. On d 21, the birds were euthanized, and the digesta were collected from the distal ileum. Sections of the duodenum, jejunum and ileum were collected for histomorphology study and the cecal content was collected for analysis of the SCFA profile. Data were analyzed as one-way ANOVA using JMP and significance was set at P ≤ 0.05. Although there was no significant treatment effect, the analyzed N and all AA content in the ileal digesta (g/kg DM) were greater for the birds fed NFDT. Ileal basal endogenous flows of N and all AA (g/kg DMI) were not significantly different but were numerically greater for the birds that received NFDT. The exceptions were Thr, Cys, Gly, Pro, Ser, and Tyr, which were numerically lower for birds fed NFDT. The percentage of individual endogenous AA in recovered endogenous protein was not significantly different except for Trp (P < 0.01), which was greater for NFDT. There was no significant treatment effect on histomorphology measurements of the small intestine sections or on the cecal SCFA profile. In conclusion, the use of soybean oil or tallow in NFD had only marginal influence on AA flow and composition of individual AA in basal endogenous losses and therefore, may not impact the determination of standardized digestible AA in feedstuffs.

Veeraganti, S. and O. Olukosi. 2025. Assessing the role of dietary fat on basal endogenous amino acid flow and composition, intestinal morphology and cecal short-chain fatty acid profile in broiler chickens. 2025 International Poultry Scientific Forum, Abstract P266.