Feed & Additive Magazine Issue 2 March 2021

SPECIAL STORY 58 FEED & ADDITIVE MAGAZINE March 2021 fish meal on the long run but it is unimaginable that insect meal will replace soybean meal in chicken feeds while keeping the feed at the same price level. The question regarding the environmental and ecological sustainability of insect meals was an- swered positively by many studies during so-called life-cycle assessments. For example, housefly larvae meal shows a much better performances compared to soybean meal regarding land use and a much better performance compared to fish meal regarding energy use and global warming potential (Fig. X). The LCA balance of BSF production can be strong- ly positive in case unused side streams of agricultural production or food processing is used. Feeding ce- reals or commodities that are in competition with direct human consumption could be seen critical. THE OLD FRIEND TENEBRIO AND THE ROLE OF CHITIN IN ANIMAL FEEDS The larvae of the beetle Tenebrio molitor are pro- duced as pet food for reptiles and birds since decades and are commonly known as “meal worm”. Due to the fact that they are rich in proteins and lipids and as they are easily to be produced in big quantities, Ten- ebrio molitor meal (TM meal) is also considered as suitable fish meal- and soy bean replacement in aqua- culture diets and in poultry diets. Several studies on feeding trials with TM meal inclusion in aquaculture diets were published in the recent years, among them studies on cold water and marine species as well as tropical ones. Comparable to the findings on BSF- and housefly meals, morphometric traits in the fish are negatively influenced from the dietary inclusion above a species-specific threshold ranging between 25 – 43%. Also, a tendency of decreasing ω -3 FA content and ω -3/ ω -6 ratio with increasing insect meal inclusion can be observed. The results might suggest that warm water species like African catfish and tilapia can cope better with TM meal than trout and Mediterranean species but the available studies are difficult to be com- pared and further investigations are necessary. The role of chitin included in insect meals is dis- cussed brisky in the last years and also recently: Chi- tin is supposed to develop anti-nutritive properties when administered in higher concentrations to fish because in the insect cuticle it is bound to a complex matrix with proteins and lipids, hardly to digest. The needed enzymes for digestion of this matrix were thought not to be abundant in all fish. Today it seems to be clear that three enzymes needed for the diges- tions of chitin (chitinase, chitobiase and lysozyme) are present in carnivorous and also in omnivorous fish in different sections of the intestinal tract. Fish species feeding naturally on benthic invertebrates, insects and crustaceans (e.g., common carp or red Fig. X: Comparison of global warming potential (GWP), energy use (EU) and land use (LU) of larvae meal, fishmeal and soybean meal (SBM) based on ton dry matter feed (From van Zanten et al. 2014) Short-antenna locust Romalea microptera Source Pixabay