R. Bras. Zootec.28/Aug/2026;55:e20250075.
Impact of dietary protease on energy, nutrient availability, and performance of broilers fed diets containing black soldier fly larvae meal
Sashka Chobanova
, Nikolay Karkelanov
, Stephen Charles Mansbridge
, Isobel Margaret Whiting
, José Henrique Stringhini
, Heloisa Helena de Carvalho Mello
, Stephen Paul Rose
, Vasil Radoslavov Pirgozliev
ABSTRACT
The experiment aimed to assess the impact of exogenous protease in diets formulated with soybean meal (SBM) or black soldier fly larvae meal (BSFLM) on nutrient retention and broiler performance. Forty-eight female Ross 308 chicks were assigned to a randomized block design study using a 2 × 2 factorial arrangement, with four treatments in total. The main factors considered were the protein source and the presence or absence of protease. Each experimental diet was fed to six pens of two birds per pen, following randomization. Dietary apparent metabolizable energy (AME), N-corrected AME (AMEn), dry matter (DMR), nitrogen (NR) and fat (FR) retention coefficients were measured. Daily feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) were assessed from 28 to 38 d of age. Data were analyzed by two-way ANOVA following a factorial arrangement. Birds fed protease consumed more feed (P = 0.036) and tended to have greater (P = 0.058) AMEn intake. There was a diet × protease interaction; birds fed the protease supplemented SBM diet grew faster than other groups (P = 0.021). Compared with the required 195 g/kg dietary crude protein (CP), the analyzed CP was 183 g/kg in the SBM diet and 203 g/kg in the BSFLM diet. Feeding diets based on BSFLM tended (P = 0.061) to lead to lower feed efficiency, e.g. higher FCR. The diets based on BSFLM also had lower ME (P<0.05) and lower FR (P = 0.001). The disparity in dietary CP likely confounded the results; therefore, conclusions regarding protease effects are limited. Further research on the impact of protease in low protein BSFLM-based diet may further elucidate the nutritive value of these enzymes for broilers.
Keywords: enzyme; growth performance; insect meal; metabolizable energy; poultry