Nutritional value of defatted larvae meal and whole larvae from black soldier fly
Abstract
Black soldier fly (BSF) larvae is a novel protein source to feed poultry. However, only nutritional values for BSF meals
are available in the literature, whereas the use of whole larvae could be a promising strategy, for instance when used
as an environmental enrichment material. Thus, this study aimed to investigate the nutritional value of three different
BSF products: defatted larvae meal (LM) and whole larvae, either dried (DL) or fresh (FL). On a dry matter (DM)
basis, crude protein (CP) and crude fat (CF) contents were respectively of 57 and 10% for LM vs 39 and 34% for
whole larvae. A total of 48 Ross 308 male boilers were randomly assigned to individual cages for a digestibility trial.
Four treatments were used: a control diet (C), a LM diet containing 75% C + 25% LM and two larvae diets containing,
on a DM basis, 75% C + 25% of FL or DL larvae. Whole larvae were distributed on top of pellets in the same feeder.
For the three products (LM, DL, and FL), the metabolizable energy (AMEn) and the apparent total tract digestibility
(ATTD) of DM, CF, CP, and gross energy (GE) were measured, as well as the standardised ileal digestibility (SID) of
amino acids (AA). The ATTD of DM, GE, and CP were significantly higher (P<0.001) for DL and FL compared to LM
(DM: 83 vs 60%; GE: 85 vs 63%; CP: 68 vs 53%). TTAD of CF was significantly higher for DL (98.2%) compared
to LM (94.6%; P<0.01) and FL (95.7%; P<0.05). The AMEn was significantly lower for LM compared to DL/FL
(2,730 vs 4,950 kcal/kg DM; P<0.001). The SID of all AA were significantly lower for LM (52-86%) compared to
DL and FL (77-98%) with respective values of 84 vs 93% for lysine and 85 vs 95% for methionine+cysteine. These
differences could be explained by the higher chitin content in LM, due to defatting process. At high concentration,
chitin is indeed known to impair nutrients digestibility. These results provide the first data on the nutritional value of
whole BSF larvae and confirm that BSF larvae are a highly digestible source of nutrients for poultry.