Effect of phase-specific dietary black soldier fly larvae supplementation on growth performance and blood biochemical indices of local breed F2 meat roosters.

Black soldier fly larvae (BSFL, Hermetia illucens) have emerged as a promising alternative protein sources for livestock and poultry feed due to their high protein digestibility and environmental friendliness. However, most studies focus on full-cycle BSFL supplementation, with limited evidence for phase-specific effects in native chickens. This study investigated the impacts of 2% and 4% BSFL supplementation during the chick (1-25 days), grower (26-50 days), or finisher (51-70 days) stage on growth performance and blood biochemical indices of Local Breed F2 Meat Roosters. A total of 3150 1-day-old roosters were randomly assigned to 7 groups (6 replicates/group, 75 birds/replicate). Growth performance was monitored at each stage, and blood biochemical indices were measured at the end of trial. Results showed that supplementation with 2% BSFL during the chick stage increased average daily gain (ADG) and decreased the feed conversion ratio (FCR), while 4% BSFL supplementation during the finisher stage reduced FCR. Both treatments were beneficial to improving growth performance. In contrast, 4% BSFL supplementation during the chick stage increased mortality rate significantly compared to control group. Phase-specific BSFL supplementation significantly altered serum total protein (TP), lipoprotein levels, liver function, and metabolic enzyme activities. Specifically, 2% or 4% BSFL supplementation enhanced TP synthesis and regulated lipid metabolism indices. In conclusion, dietary supplementation with 2% BSFL during the chick stage is an optimal strategy to improve growth performance and metabolic health of native chickens, providing practical guidance for sustainable poultry production.