Insect meal is gaining increased attention in aquafeed formulations due to high protein content and an essential amino acid profile similar to that of fishmeal. To investigate insect meal in feed for European perch Perca fluviatilis, a promising candidate for European intensive culture, we replaced standard fishmeal with partially defatted black soldier fly Hermetia illucens larva meal at rates of 0%, 20%, 40% and 60% (groups CON, H20, H40 and H60, respectively) and compared growth performance, somatic indices, hematological parameters, whole-body proximate composition and occurrence of spleen lipidosis. In addition, we assessed the economic and environmental sustainability of the tested feeds by calculating economic conversion ratio (ECR) and economic profit index (EPI). The tested groups did not differ in survival rate. Significant differences were documented in final body weight and specific growth rate, with the highest values in CON, H20 and H40. The proximate composition of fish whole-body at the end of the experiment did not differ in dry matter, crude protein or ether extract, while organic matter, ash and gross energy composition showed significant differences. The fatty acid content and n-3/n-6 ratio showed a decreasing trend with increasing H. illucens larva meal inclusion. No differences were found in hematological parameters among tested groups. The H. illucens larva meal inclusion significantly affected ECR and EPI, even at 20% inclusion level the cost of diets did not differ from the control fish meal based diet. Results suggested that 40% inclusion of H. illucens larva meal can be used successfully in standard diets for perch.

This study investigated the feasibility of using clove oil, 2-phenoxyethanol, or Propiscin as an alternative to tricaine methane sulphonate (MS 222) as a ¢sh anaesthetic, particularly in regard to reducing ¢sh stress. The biochemical blood pro¢les of perch Perca £uviatilis L. anaesthetized with either MS 222 (100 mg L À 1 ), clove oil (33 mg L À 1 ), 2-phenoxyethanol (0.40 mL L À 1 ) or Propiscin (1.0 mL L À 1 ), and a non-anaesthetized control group were compared. Biochemical pro¢les were determined from blood samples collected before treatment in controls. For each anaesthetic tested, ¢sh were divided into two groups, one sampled immediately after 10-min anaesthesia and a second, sampled 24 h after 10-min anaesthesia. The values determined in the present study suggested that internal organs and tissues of perch were slightly altered by MS 222, clove oil and 2-phenoxyethanol anaesthesia, but not by Propiscin anaesthesia.

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We retrieved data from various studies to investigate the consequences of insect meal production and insect meal‐based diets with respect to their environmental impact, including global warming potential, energy use, land use, water use, acidification, eutrophication as well as to economic fish‐in fish‐out ratio and solid waste output production. Analysis indicated that insect meals’ production exerted positive effects on land use but was associated with greater energy use and a larger carbon footprint compared to conventional protein sources. Substitution of silkworm meal (Bombyx mori) meals for fishmeal in aquatic animal diets significantly reduced solid phosphorus waste compared to insect‐free diets. In contrast, the inclusion of black soldier fly (Hermetia illucens), housefly (Musca domestica), mealworm (Tenebrio molitor) and grasshopper (Zonocerus variegatus) has led, in comparison to insect‐free diet, to greater solid nitrogen waste. Reducing the proportion of fishmeal and, to a lesser extent fish oil, by various insect meals in aquatic diet formulations significantly reduces economic fish‐in fish‐out, indicating less marine forage fish required per unit fish yield. The simulated data showed environmental benefit associated with land use of insect‐containing aquafeeds compared to insect meal‐free feeds, especially insect species of M. domestica and T. molitor. In all, this study suggested a trade‐off of using insect meal as an aquafeed ingredient regarding environmental consequence. Since insect meal has excellent potential to supply protein for aquafeeds in the coming years, improvement in insect meal production systems and nutritional composition will be essential to make insect meal a sustainable aquafeed ingredient.

The present work employed a systematic review and meta‐analysis to quantify the overall effects of various types of insect meal on special growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) of aquatic animals. A total of 107 studies published from 1990 to 2021, targeting 23 freshwater and 17 marine fish species, employing 17 insect species as a replacement for fishmeal, was compiled. Overall, a significantly higher Hedges’ g value for SGR and lower FCR was found in aquatic animals fed dietary larval defatted mealworm Tenebrio molitor and pupal full‐fat silkworm Bombyx mori compared with fishmeal diet. The majority of dietary insect meals had a negative linear correlation with Hedges’ g of growth performance, except larval fly Chrysomya megacephala, which had a positive linear relationship, and of prepupal defatted black soldier fly Hermetia illucens, which had a negative quadratic relationship. Some insect meals, including G. bimaculatus, adult grasshoppers of Oxya fuscovittata and Zonocerus variegatus and larval full‐fat Cirina butyrospermi, supported adequate growth of aquatic animals at plausible inclusion levels. At as low as 2.2%, insect‐derived chitin supported growth performance and improved feed utilization of marine fish species. In the quest to minimize fishmeal in aquafeeds, insect meal holds enormous potential but is not the sole option; rather, integrating insect meal and novel/conventional materials is more strategic. The present study lays the groundwork for further multidisciplinary considerations for the effective use of insect meal as an alternative aquafeed protein with the goal of long‐term sustainability.

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The aim of the present study was to study spawning stimulation in artificial reproduction of females pikeperch (Sander lucioperca L.) using ''Chorulon'' containing the human chorionic gonadotropin (hCG) and compare with ''Supergestran'' containing a mammalian GnRH ([D-Ala 6 ]GnRHProNhet) analogue. The females were divided into eleven experimental groups and injected with hCG at 250, 500, 750, and 1 000 IU kg -1 body weight (BW) and mGnRHa at 1, 2.5, 5, 10, 25, and 50 lg kg -1 BW. In all treatments, a single intramuscular injection of hormone was performed. Control group was injected with 0.9 % NaCl, 0.9 cm 3 kg -1 BW. The average percentages of ovulating females were 88.5 ± 12.3 and 80.8 ± 10.9 % in hCG-and mGnRHa-treated groups, respectively. The average diameter of eggs was 0.95 ± 0.06 and 0.98 ± 0.06 mm in hCG-and mGnRHatreated groups, respectively. Neither ovulation rate nor diameter of egg was statistically differed among hormonally treated groups. Statistical difference was observed only in hatching rate, where the average were 73.6 ± 14.4 and 50.6 ± 17.7 % in hCG and mGnRHa-treated groups, respectively. Among hormonally treated groups, the best results were observed in groups treated with hCG at 500 and 750 IU kg -1 and in groups treated with mGnRHa at 25 lg kg -1 . No ovulation was observed in the control group. This study indicated successful ovulation in pikeperch using a single intramuscular injection of hCG or mGnRHa analogue.

Dynamics of sperm motility (sperm velocity, percentage of motility and flagellar beat frequency) and monthly variations of semen characteristics (semen volume and osmolality and sperm concentration and motility) were studied in Perca fluviatilis. This study showed that sperm velocity, percentage of motility and flagellar beat frequency significantly and rapidly decreased after the activation of sperm motility. Twelve spermiating males were randomly selected and electronically tagged to study monthly variations of semen characteristics. The semen was collected 4 times