Effects of different blending ratios of lard and chicken fat on growth performance, nutrient utilization, serum lipid metabolism, and tissue fatty acid composition in meat ducks.

This study aimed to evaluate the effects of lard and chicken fat blending ratios on growth performance, nutrient availability, serum lipid metabolism, and tissue fatty acid composition in meat ducks aged 14 to 42 days. A total of 480 14-day-old meat ducks were randomly divided into 6 treatment groups (8 replicates per group, 10 ducks per replicate), with a total dietary fat addition level of 7.5 %. The dietary ratios of lard to chicken fat were 100:0 (T1), 80:20 (T2), 60:40 (T3), 40:60 (T4), 20:80 (T5), and 0:100 (T6). Results showed that the T3 group (60:40) achieved the lowest feed-to-gain ratio, which significantly outperformed (P < 0.05) the pure lard (T1), pure chicken fat (T6), and high-chicken fat groups (T4,T5). Meanwhile, the DM and phosphorus availability in the T3 group were significantly higher (P < 0.05) than those in all other groups and the gross energy utilization as well as AME in the T3 group were significantly higher (P < 0.05) than those in the T1 and high-chicken fat groups (T4-T6). Serum lipid homeostasis was optimized in the T3 group, maintaining the lowest total cholesterol and LDL-C levels (P < 0.05). Fatty acid profiling revealed distinct metabolic partitioning: while leg muscle and subcutaneous fat displayed a sensitive "dietary mirroring" effect, breast muscle maintained lipid homeostasis. These results suggested that the 60:40 lard-to-chicken fat blend constitutes the optimal lipid strategy, which potentially enhances feed efficiency and mineral absorption and optimized systemic lipid clearance and tissue lipid deposition.