Growth and survivability of the black carpet beetle fed a whole feather diet

Keratin waste has become a significant side effect of meat production and processing that needs urgent addressing. In this study, we explore the potential of the black carpet beetle as one of the few species known to metabolize feather keratin. Rearing larvae on raw feathers revealed an increased mortality but no significant differences in the number of larval moults compared with the control diet, although growth was stunted. At the end of the study, up to 42% of the original feather mass was consumed by the larvae, with approximate digestibility varying between 68%-89%. Gut enzyme analysis confirmed keratinolytic activity in the larval digestive tract. Furthermore, protein content in larvae reared on a feather diet surpassed control-fed larvae in overall protein content (0.790 mg/ml vs. 0.628 mg/ml per 1 mg of live larval weight). Our study demonstrated the black carpet beetle as a promising biological fermenter for sustainably converting feather protein into insect protein.