Protein quality of insects as potential ingredients for dog and cat foods

Abstract

Insects have been proposed as a high-quality, efficient and sustainable dietary protein source. The present study evaluated the protein quality of a selection of insect species. Insect substrates were housefly pupae, adult house cricket, yellow mealworm larvae, lesser mealworm larvae, Morio worm larvae, black soldier fly larvae and pupae, six spot roach, death's head cockroach and Argentinean cockroach. Reference substrates were poultry meat meal, fish meal and soyabean meal. Substrates were analysed for DM, N, crude fat, ash and amino acid (AA) contents and for in vitro digestibility of organic matter (OM) and N. The nutrient composition, AA scores as well as in vitro OM and N digestibility varied considerably between insect substrates. For the AA score, the first limiting AA for most substrates was the combined requirement for Met and Cys. The pupae of the housefly and black soldier fly were high in protein and had high AA scores but were less digestible than other insect substrates. The protein content and AA score of house crickets were high and similar to that of fish meal; however, in vitro N digestibility was higher. The cockroaches were relatively high in protein but the indispensable AA contents, AA scores and the in vitro digestibility values were relatively low. In addition to the indices of protein quality, other aspects such as efficiency of conversion of organic side streams, feasibility of mass-production, product safety and pet owner perception are important for future dog and cat food application of insects as alternative protein source.

Nutritional value of three <i>Blattodea</i> species used as feed for animals

“…These findings are more or less in line with the results published by other authors. For adult females of the same species, Bosch et al (2014) reported high contents of valine, leucine, histidine, lysine and arginine, which is consistent with the levels found in B. dubia in this study. Moreover, Józefiak et al (2016) studied the EAA composition of B. lateralis subadult nymphs and found that tyrosine, arginine, valine and lysine were among the first five EAAs, which corresponds to the results obtained in this study.…”

“…In all of the examined cockroaches high concentrations of crude protein (470-652 g · kg −1 DM) as well as high levels of crude fat (145-363 g · kg −1 DM) were determined. This means that both subadult and adult cockroaches used in our study are a similar source of protein and lipids like other species of cockroaches (Oonincx and Dierenfeld, 2012;Bosch et al, 2014), house cricket (Acheta domesticus) (Barker et al, 1998;Finke, 2002) and other insects.…”

“…In all tested samples contents of glycine (66.4-166.2 g · kg −1 DM) and alanine (81.5-118.4 g · kg −1 DM) were very high. It is more than in other studies focused on the protein quality in cockroaches, e.g., Yi et al (2013) and Bosch et al (2014). These differences were probably caused by feed residues in the cockroach digestive tract.…”

“…Information concerning the nutrient content of the investigated species is only available for the adults of B. dubia (Yi et al, 2013;Bosch et al, 2014) and young nymphs of B. lateralis (Oonincx and Dierenfeld, 2012). Therefore, the results should be compared mainly with other cockroaches or insect species.…”

“…On the other hand, Bosch et al (2014) found that in vitro digestibility of insect protein is lower than that of commercially available protein feedstuffs. The quality of lipids depends on ABSTRACT.…”