Evaluation of a threonine fermentation product as a digestible threonine source in broilers

In the present experiment, a Thr fermentation product (FP) (75% minimum digestible Thr) was evaluated as a replacement for crystalline L-Thr (98.5% minimum digestible Thr) as a source of digestible Thr and other nutrients to support broiler performance (0–48 d) and processing characteristics. Five phase-fed diets included 1) a positive control (PC) diet containing L-Met, L-Lys•HCl, and L-Thr, 2) a reduced protein control (RPC) diet with added L-Val, L-Ile, and L-Arg, 3) a negative control (NC) identical to the RPC except that cellulose was added at the expense of L-Thr, 4) a RPC diet with Thr-FP used in place of L-Thr with only accounting for digestible Thr and energy contributions of the FP (TFP), and 5) a RPC diet with Thr-FP used in place of L-Thr and accounting for the full nutrient matrix of the FP (TFP-FM). Overall, broilers fed the RPC diet had similar growth performance compared to birds fed the PC diet, whereas broilers fed the NC diet had reduced BW gain and increased FCR compared to the RPC-fed birds. Birds fed either the TFP or TFP-FM diet had similar growth performance to the RPC-fed birds. At processing, broilers fed the RPC diet had similar parts yields, excluding wings, to the PC group. Parts yields for the Thr-FP and NC groups were similar to the RPC group. These data confirmed the importance of adequate dietary Thr concentration in maximizing broiler performance and that Thr provided by the Thr-FP supported equivalent performance to L-Thr.