The Decomposition Ability and Environmental Impact of Laying Hen Manure Treated With Black Soldier Fly Larvae

Adding black soldier fly (BSF) larvae to animal manure enhances composting and environmental outcomes, producing organic fertilizer. However, the environmental impact of laying hen manure treated with BSF larvae remains poorly understood. This study, therefore, aimed to evaluate the decomposition ability, ammonia production, and proximate composition of laying hen manure at different instar stages of BSF larval treatment. The treatments included (1) 200 g of 2nd instar and (2) 200 g of 3rd instar BSF larvae/2000 g of laying hen manure. BSF larvae had no significant effect on the decomposition ability of laying hen manure during the experimental period. No significant difference in ammonia production was determined between the two groups on days 0 to 10, except on Days 15, 20, 25, and 30, when the differences were statistically significant ( p < 0.05). In addition, no significant differences in pH, moisture, TN, CA, or ADF content of laying hen manure were detected between the 2nd and 3rd instar of BSF larvae; however, the NDF content showed significant differences between the two groups ( p < 0.05). In terms of environmental impact, the 2nd instar BSF larvae groups increased decomposition ability and proximate composition of laying hen manure or decreased ammonia production compared with the 3rd instar BSF larvae groups. In conclusion, using the 2nd instar of BSF larvae on laying hen manure had a beneficial effect on the environmental impact and enhanced larval development under optimal conditions, which may be associated with pH.