The Immature Stages of Sarcophaga dux (Diptera; Sarcophagidae): A Proposed Nutritional Source for Poultry

Background: Insects, particularly those belonging to the order Diptera, offer a promising alternative protein source for poultry with numerous advantages. Among these, Sarcophaga dux (Diptera: Sarcophagidae), a widely distributed global dipteran species, including Saudi Arabia, exhibits potential for waste management. This study was conducted to investigate the nutritional values of both larval and pupal stages of S. dux as well as the feed intake (FI) and the feed conversion ratio (FCR). S. dux flies (≈170 to 200 newly hatched larvae) were reared in standardized laboratory conditions until reaching the pupal stage. Methods: The daily feed intake was calculated for each larvae replicate and FCR was measured on the last day of the 3rd larval instar. Larvae and pupae from each replicate were subject to the proximate analysis, amino acids and minerals. Results indicated a progressive increase in FI throughout the development period, except for the last day of the 3rd larval instar. Result: The FCR demonstrated a higher value comparing to previous study. Furthermore, both larval and pupal stages exhibited high crude protein, lipid content and crude fibre with low dry matter and elevated ash content. The amino acid and mineral contents were also high, with low levels of heavy metals. Notably, the pupal stage displayed superior results in this study. These results may indicate that larvae and pupae of S. dux are promising sources of protein, minerals and potentially other essential nutrients which, in fact, suggest it as a nutritionally valuable food sources for poultry. Upon comparing the larval and pupal stages, it is evident that essential minerals are generally abundant in both stages except for manganese (Mn), which was found to be highest in pupae. However, it is noteworthy that the levels of heavy metals in both stages were low and exhibited no significant difference except for lead (Pb).