Taurine content of insects used as feed

Abstract

Taurine (2-aminoethane sulfonic acid) is an important bioactive compound which certain living organisms cannot synthesise metabolically, thus requiring its dietary supplementation for normal physiological processes. As recent research has shown insects to be a suitable high-quality feed source this study analysed taurine content in ten commercially available insect species (Alphitobius diaperinus, Acheta domesticus, Blaberus craniifer, Blatta lateralis, Gryllus assimilis, Hermetia illucens, Musca domestica, Periplaneta americana, Schistocerca gregaria, and Tenebrio molitor) by an electrophoretic method. Levels of total nitrogen substances (Kjeldahl method) and chitin (spectrophotometric method after hydrolysis to glucosamine) present in the insect samples were also determined. Amongst the samples, G. assimilis contained the highest levels of taurine (121.0±10.2 mg/100 g fresh weight; 436±34 mg/100 g dry matter). On the contrary, the lowest taurine level was detected in S. gregaria (5.4±0.6 mg/100 g fresh weight; 15±2 mg/100 g dry matter). Taurine levels were determined for the whole insect and calculated per protein content. There was no significant correlation between the taurine content and the insect order or developmental stage of insects. Though it has been proved that insect species are variable sources of taurine, the most taurine-rich insect species are comparable with conventionally used feeding ingredients such as fishmeal, animal muscles and visceral tissue.