evaluation of various commodities for the development of the yellow mealworm, Tenebrio molitor christos i. Rumbos 1,2 , ioannis t. Karapanagiotidis 2 , eleni Mente 2 , pier psofakis 2 & christos G. Athanassiou 1* We evaluated the suitability of forty-four commodities (i.e., cereal flours and meals, non-flour, cereal commodities, legumes and various commodities of vegetative and animal origin) as oviposition and feeding substrates for the yellow mealworm, Tenebrio molitor. Τen T. molitor adults were introduced in plastic vials containing 30 g of each commodity. At the end of the 1 week period, all adults were removed, and mortality was determined; then the vials were further incubated for additional 9 weeks. After this time, the vials were opened, and the larvae of each vial were separated from the feeding substrate, counted and weighed as a group. The efficiency of ingested food conversion was calculated for each substrate. finally, proximate composition was calculated to determine the nutrient components of the feeding substrates tested and the T. molitor larvae that fed on various selected substrates. in general, adult reproduction was clearly favoured by most amylaceous substrates tested, which was in contrast to the tested legumes on which fewer offspring were produced. Similar effects were observed for larval development. feeding on selected substrates exerted an impact on the nutrient composition of T. molitor larvae, with a high protein content of the substrate usually resulting in a high protein content of the larvae. Over the last few years, "insect farming" has attracted considerable scientific attention, as insects are considered an alternative and sustainable nutrient source for animal feed and human food 1-5. Among the most promising insect species for industrial utilization and commercial large-scale production is the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae). This species is one of the largest stored-product beetles (adult body length between 12 and 20 mm) that is commonly found infesting stored agricultural products 6. It is a cosmopolitan stored product insect pest that is found in various types of facilities and commodities, mainly grains and related amylaceous commodities, such as flour, bran and pasta 6. Nevertheless, there is strong interest in its utilization as a food source for humans and animals, including fish 1. This is because T. molitor larvae are highly nutritious with high protein and lipid contents 7,8. Because of their nutritional value, the larvae of T. molitor are commonly used as feed for pets (e.g., reptiles and birds) 9 , whereas they have been successfully evaluated as a feed ingredient in pig 10 and poultry diets 11,12 , as well as in artificial diets for the mass-rearing of beneficial organisms, such as the predatory lady beetle, Coleomegilla maculata De Geer (Coleoptera: Coccinellidae) 13. Recently, T. molitor was included in the list of insect species that are allowed to be used as ingredients in fish feeds in the EU 14 , whereas its exploitation f...

In order for aquaculture to satisfy the increasing demand for farmed fish, it is essential that the sector continues searching for suitable alternatives to fishmeal (FM) that are both cost-effective and widely available. Over the last decades, plant proteins have been used successfully to reduce the inclusion levels of FM in the diets of most farmed fish species, but the high inclusion levels reduce feed intake, fish growth and nutrient bioavailability in fish body, having also negative impacts on the aquatic environment (Bell & Waagbø, 2008;Hardy, 2010). Further, the prices of many plant proteins have increased dramatically over the last decades because of the increasing demand for their use in feeds, human foods and ethanol production (Hardy, 2010). Of most importance, however, is the fact that as the aquafeed sector is expanding to satisfy the increasing demand of intensive aquaculture for aquafeeds, greater amounts of FM are required; thus, the exploration for suitable and cost-effective protein alternatives is ongoing. AbstractTwo feeding trials examined the replacement of fishmeal (FM) with poultry byproduct meal (PBM) in the diet of juvenile Sparus aurata. In Feeding trial I (100 days), three diets were formulated, where FM protein was replaced by 50% (PBM50) and 100% (PBM100) PBM, while in Feeding trial II (110 days), four diets were formulated using the same FM control diet, but FM was replaced at lower levels: 25% (PBM25), and 25% (PBM25 + ) and 50% (PBM50 + ) with the supplementation of lysine and methionine amino acids. PBM protein can successfully replace 50% of FM protein in the diet of S. aurata without adverse effects on survival, feed intake, growth performance and feed utilization, given that the diet is balanced with lysine and methionine.The proximate composition of body and muscle was unaffected by the diet, but the total FM replacement resulted in reduced lipid and energy contents in fish. A fifty per cent FM replacement by PBM did not affect haematological parameters indicating a good fish health. Similarities in trypsin and chymotrypsin activities with FM-fed fish suggest a high digestibility of PBM. High dietary levels of PBM reduced the liver gene expression of GH/IGF axis and of cathepsin D suppressing fish growth and modulating the protein turnover. K E Y W O R D Sdigestive enzymes, fishmeal replacement, gene expression, gilthead seabream, haematological parameters, poultry by-product meal

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Insect proteins are considered as suitable low environmental impact alternatives to fishmeal for sustainable aquafeeds. Among the different insect species, Hermetia illucens has attracted research and industrial interest due to its ability to grow well on organic side streams, its high protein content and favorable amino acid profiles. Its lipid content although high is characterized by a lack of EPA and DHA that are essential to fish nutrition and thus a defatted form of Hermetia meal might be of better use in fish diets. Hence, two feeding trials were conducted to investigate the effects of the partial fishmeal replacement by increasing levels of a full-fat (up to 276 g/kg) and a defatted (up to 174 g/kg) H. illucens meal on feed intake, growth, feed utilization and nutrient compositions of gilthead seabream (Sparus aurata). Results showed that both the fat content and the inclusion level of H. illucens meal are critical for the success of fishmeal replacement in the diets of S. aurata as they strongly affect feed consumption. A lower palatability of H. illucens meal was observed when included at high dietary levels with the defatted form being more readily accepted by fish. The defatted H. illucens meal is more suitable than the full-fat type to replace fishmeal, with a dietary level of about 81–104 g/kg supporting the highest feed consumption, the highest growth, an unaffected proximate composition and a better feed utilization by S. aurata.

The effects on liver and intestinal histomorphology and on intestinal microbiota in gilthead seabream (Sparus aurata) fed diets that contained poultry by-product meal (PBM) and hydrolyzed feather meal (HFM) as fishmeal replacements were studied. Fish fed on a series of isonitrogenous and isoenergetic diets, where fishmeal protein of the control diet (FM diet) was replaced by either PBM or by HFM at 25%, 50% and 100% without amino acid supplementation (PBM25, PBM50, PBM100, HFM25, HFM50 and HFM100 diets) or supplemented with lysine and methionine (PBM25+, PBM50+, HFM25+ and HFM50+ diets). The use of PBM and HFM at 25% fishmeal replacement generated a similar hepatic histomorphology to FM-fed fish, indicating that both land animal proteins are highly digestible at low FM replacement levels. However, 50% and 100% FM replacement levels by either PBM or HFM resulted in pronounced hepatic alterations in fish with the latter causing more severe degradation of the liver. Dietary amino acid supplementation delivered an improved tissue histology signifying their importance at high FM replacement levels. Intestinal microbiota was dominated by Proteobacteria (58.8%) and Actinobacteria (32.4%) in all dietary groups, but no specific pattern was observed among them at any taxonomic level. This finding was probably driven by the high inter-individual variability observed.