Comparison of Capacity of 4th and 6th Instar Tenebrio molitor Larvae to Improve Biodegradation and Minimize Environmental Impact of Poultry Manure Treated With Coffee Marc and Bentonite

Sustainable approaches to managing poultry waste, such as its use as manure, are urgently required to address emerging concerns under increasing demand for poultry products. Incorporating coffee marc and bentonite as part of the waste processing by Tenebrio molitor (TM) larvae presents effective strategies for addressing these challenges. The present study investigated the capacity of 4th and 6th instar TM larvae to biodegrade poultry manure following treatment with coffee marc or coffee marc and bentonite, based on ammonia (NH 3 ) contents and physicochemical characteristics of poultry manure. The three treatments adopted in the present study included 2 kg of poultry manure (T1), 1 kg of poultry manure + 1 kg of coffee marc (T2), and 1 kg of poultry manure + 0.9 kg of coffee marc + 0.1 kg of bentonite as a basis of 0.2 kg of 4th or 6th instar TM larvae (T3). The 4th and 6th instar TM larvae had no significant effect on biodegradation capacity. Nevertheless, a significant difference in NH 3 flux occurred during the experiments. In the 4th instar TM larvae treatments, significant differences in pH, total nitrogen (TN), and ADF occurred among all treatments; conversely, in the manure treated with coffee marc and bentonite, 6th instar TM larvae had significant effects on pH, dry matter (DM), TN, ADF, and NDF content compared with only poultry manure. In conclusion, 6th instar TM larvae reared on poultry manure with coffee marc and bentonite could decrease the environmental impact during composting.