Amino acid requirements of yellow mealworm and black soldier fly larvae

In order to achieve optimal growth and health of farm animals, a different amount/ratio of essential amino acids in the feed is necessary in each phase of life. Knowledge about which amino acids are essential and in which quantities/proportions they are best administered has already greatly advanced the pig and poultry sector and is still being generated today. For the still young, rapidly developing insect sector, this knowledge could mean a major step forward towards breeding optimization. Therefore, in this research the needs of the 2 most commercially reared insect species, namely mealworms (Tenebrio molitor) (MW) and black soldier fly larvae (Hermetia illucens) (BSF), were investigated. The focus was on requirements for lysine, methionine, threonine, phenylalanine and tryptophan based on evidence from the literature and those of pigs. Semi-artificial diets based on at least 25% wheat bran (MW) and chicken feed/water (30/70) (BSF) (basic feed important for structure and certain micronutrients) supplemented with sugar and synthetic amino acids were tested. The diets were isoenergetic and isoproteinous. Of the amino acids studied, one was administered in different doses per experiment. The non-essential glutamic acid was used as a substitute at lower doses. Growth, as measured by weight gain, and survival were observed. The following results were for MW and BSF respectively. For lysine from a content of 0.35 g/100 g diet and 0.53 g/100 g diet no extra growth was noticeable. For methionine this was from 0.13 g/100 g and 0.16 g/100 g. Each time more threonine was given, a significant difference could be noticed and the minimum doses were around 0.42 g/100 g and 0.49 g/100 g. With tryptophan, for MW, there were no differences between the different concentrations. At the lowest dose of 0.06 g/100 g the maximum growth was already reached, whereas for BSF this was at 0.13 g/100 g.