Effects of Compound Ratio of Agricultural By-Products and Fox- Raccoon Dog Dung on the Growth and Development of Black Soldier Flies

<title>Abstract</title> <p>To explore the optimal compound feed formula of fox-raccoon dog dung mixed with agricultural by-products for the growth and development of black soldier flies (Black soldier fly), four common agricultural by-products (distillers' grains, rice bran, potato residue, and wheat bran) were mixed with fresh fox-raccoon dog dung at a 1:1 ratio to prepare compound feed. Single-type agricultural by-products and pure fox-raccoon dog dung were used as the control groups. We reared fourth-instar black soldier fly larvae (BSFL) and determined their growth and development indicators, including larval and prepupal body length and weight, larval survival rate, pupation rate, emergence rate, developmental duration of each instar, as well as feed conversion ratio. The results showed that the 1:1 wheat bran-fox-raccoon dog dung group performed optimally in all indicators. Its larval and prepupal weights were significantly higher than those of other compound groups, with a feed conversion ratio of 0.4305, which indicated the highest feed conversion efficiency. Its larval survival rate, pupation rate and emergence rate all exceeded 80%, and the larval and pupal developmental durations were shorter, significantly promoting Black soldier fly growth and development. The other three compound groups could meet the growth needs of Black soldier fly but with inferior effects. Feeding on pure fox-raccoon dog dung significantly inhibited the growth and development of Black soldier fly. This study identified the optimal compound ratio as 1:1 wheat bran to fox-raccoon dog dung, which provides a technical reference for the resource utilization of fox-raccoon dog dung via Black soldier fly.</p>