Effects of dietary 1,3-diacylglycerol supplementation on growth performance and fat utilization in broilers fed palm kernel meal-based reduced-energy diets.

This study evaluated the effects of 1,3-diacylglycerol (DAG) supplementation on the growth performance, nutrient digestibility, and physiological responses of broilers fed reduced-energy diets containing palm kernel meal (PKM). A total of 576 one-day-old mixed-sex Ross 308 broiler chicks were randomly allocated to four dietary treatments: positive control (PC), negative control (NC; PC - 100 kcal/kg ME and 5% PKM), T1 (NC + 0.05% 1,3-DAG), or T2 (NC + 0.10% 1,3-DAG). Broilers were fed the experimental diets for 35 d, and apparent total tract digestibility was determined during d 28-35 using chromium oxide as an indigestible marker. During the overall period (d 1-35), body weight gain and feed intake were not affected by dietary treatment (P > 0.05), whereas the feed conversion ratio (FCR) was significantly higher in the NC group than in the PC group (P < 0.001). Dietary 1,3-DAG supplementation linearly improved FCR (P < 0.001), and the FCR of the T2 group was comparable to that of the PC group. The apparent total tract digestibility of DM, nitrogen, energy, and fat was not affected by treatment (P > 0.05); however, significant linear increases in DM (P = 0.049), energy (P = 0.015), and fat digestibility (P < 0.001) were observed with increasing 1,3-DAG supplementation. Nutrient intake and retention were largely unaffected by treatment (P > 0.05), although fat intake was significantly higher in the NC group than in the PC group (P = 0.012). In contrast, nutrient excretion, particularly fat excretion, was significantly reduced by 1,3-DAG supplementation in a dose-dependent manner (P < 0.001). Serum lipid profiles and rectal temperature were not influenced by dietary treatment (P > 0.05). In conclusion, dietary 1,3-DAG supplementation improved FCR in broilers fed PKM-based reduced-energy diets by enhancing nutrient utilization, particularly fat digestibility, without affecting their physiological parameters.