Evaluating amino acid requirements of neonatal black soldier fly larvae

Summary in the original language of the document

Amino acid (AA) requirements of black soldier fly larvae (BSFL) during the early nursery phase remain poorly understood. We conducted a feeding trial including a semi-artificial low-protein nursery diet (NC) that was complemented with 20 free AA to reach 18% protein content (PC) and to simulate the AA profile of a commercial laying hen feed (RC). In 12 additional treatments, relative to PC levels, either Arg, Ile, Lys, Met, Thr, or Trp contents were reduced by 31-46% via leaving out respective free AA or individually supplemented to 131-146% (-AA vs. +AA treatments). Each treatment was triplicated with 10,000 freshly hatched (naïve) BSFL and restrictively provisioned with 10 mg dietary dry matter per larva. Growth was most delayed with NC and -Lys. Conversely, -Met and -Trp responses were similar to PC while growth curves for -Arg, -Ile and -Thr were intermediate. Adding Met, Thr, Trp, and Ile did not improve performance over PC, but +Lys and +Arg both steeped growth, resulting in fastest readiness for fattening. All single -AA treatments needed 1-5 days more than respective +AA treatments to reach critical larval live weights (~10 mg). For the actual basal diet, we conclude that neonate BSFL growth is first limited by Lys and co-limited by Arg, Ile and Thr, whereas Met and Trp seem indifferent.