Comparative protein quality in black soldier fly larvae meal vs. soybean meal and fish meal using classical protein efficiency ratio (PER) chick growth assay model

ABSTRACT: Black soldier fly larvae meal (BSFLM) is a relatively new ingredient that has attracted attention for application in human, farm, and companion animal nutrition. However, there is limited data on protein quality (PQ) of BSFLM. This study compared PQ in BSFLM with soybean meal (SBM) and fishmeal (FM) using the classical protein efficiency ratio (PER) chick growth assay model. A total of 240-male day-old Ross × Ross broiler chicks were allocated to 6 test diets for 10 d test. The corn starch-dextrose based diets were: 5 test diets containing 10% crude protein (CP) from casein (as a standard assay diet), SBM, FM, or BSFLM without or with (BSFLM+) additional essential amino acids (EAA) to match the levels of the SBM diet on digestible basis. A sixth diet was nitrogen-free (NFD), to enable calculation of net protein ratio (NPR). The birds had ad libitum access to feed and water, body weight (BW) and feed intake (FI) were recorded at the beginning and end of the experimental feeding period. Body weight gain (BWG), gain to feed ratio (G:F), crude protein intake (CPI), PER, and NPR were calculated. The analyzed CP (as fed) was 10.1, 12.8, 9.5, 11.7, and 14.9% for casein, SBM, FM, BSFLM, and BSFLM+ diets, respectively. Birds fed BSFLM+ had greater BWG (P < 0.01) than birds fed other diets. Feed intake was greater (P < 0.01) for birds fed BSFLM+ and FM diets than birds fed other diets. Birds fed BSFLM+ ate (P < 0.01) more CP than birds fed other diets. Diets had no (P > 0.05) effects on PER and NPR. In terms of ranking, the PER was 2.44, 2.38, 2.34, 2.28, and 2.10 g BWG/g CPI for BSFLM+, SBM, FM, casein, and BSLM, respectively. Corresponding values for NPR were 2.69, 2.78, 2.70, 2.74, and 2.48 g BWG/g CPI, respectively. In conclusion, the protein quality of BSFLM without or with additional EAA was comparable with FM and SBM.