Effect of Poultry Offal as a Substrate for Black Soldier Fly Larvae Production

Feed is the largest expense in poultry production. Black soldier fly larvae (BSFL) can replace soybean and fish meal, lower costs, and offer environmental benefits. Their growth and nutrition depend on the substrate, and broiler processing generates about 25% inedible offal that must be managed to avoid negative impacts. This study investigated the suitability of broiler offal, either alone or in mixtures with manna grass (Cymbopogon nardus), as a substrate for BSFL rearing. A completely randomized design was used with six treatments: Six days old BSFL were introduced into substrates having either food waste (FW) as the control, 100% poultry offal (P100M0), 75% poultry offal+25% manna grass (P75M25), 50% poultry offal+50% manna grass (P50M50), 25% poultry offal+75% manna grass (P25M75), and 100% manna grass (P0M100). Larvae grown on FW, P50M50, and P25M75 reached the prepupal stage within 13 days. Survival rate of BSFL grown on FW (86%) was not significantly different from those on P50M50 (81%), P25M75 (83%), and M100 (88%). Survival rate on Poultry offal alone (3.7%) or even high offal level, P75M25 (40%) was extremely low. However, day 13 weight of larvae on P75M25 (109 g) was similar to those on FW (110 g). Manna alone (14 g) or offal alone (56 g) did not support for good larval growth. Among the offal manna combinations, the best larval weight was reported on P50M50. Larval crude protein content was similar on FW and P0M100. Interestingly, all manna and offal combinations as substrates resulted in higher CP contents (46%-49%). Substrate reduction rate, waste reduction index, bioconversion ratio, and N conversion ratio of larvae on P50M50 were statistically similar to those on FW. The study concludes that broiler offal or Manna grass alone is not a suitable substrate for BSFL production. The P50M50 mixture showed higher CP and similar waste conversion, but further studies are needed to improve survival and growth. Keywords: BSF, Poultry offal, Substrate, Growth, Composition