Dietary Fish Meal Replacement with Hermetia illucens and Tenebrio molitor Larval Meals Improves the Growth Performance and Nutriphysiological Status of Ide (Leuciscus idus) Juveniles

Abstract

The ide (Leuciscus idus) is a native European species of rheophilic cyprinid fish whose wild population status is dependent on conservation efforts, particularly regular restocking. This study aimed to evaluate the effects of including insect meals as a component in the diet of ide juveniles on their growth performance, feed utilization, and nutriphysiological status. Four diets were formulated: three with insect meals, HI–with 20% Hermetia illucens meal, TM–with 20% Tenebrio molitor meal, and ZM–with 20% Zophobas morio meal, and the control group diet, CON–fish meal with no insect component. The effects of the various diets on the efficiency of rearing ide juveniles were assessed based on fish growth parameters, feed utilization parameters, somatic indices, and intestinal and hepatopancreatic histomorphology. The highest increase in fish weight gain and the protein efficiency ratio was observed in the HI and TM groups, while the lowest values were observed in the CON and ZM groups. Comparable results were noted for the feed conversion ratio, which was most favorable in the HI and TM groups and increased in the ZM group. The use of black soldier fly and mealworm larval meal in the diets of ide juveniles had a positive effect on rearing results and overall fish health.

Insect rearing on biowaste represents a competitive advantage for fish farming

“…It has been reported that feeding fish by BSF adults has its limitations, as increased chitin levels of fully developed adult can reduce digestibility and nutrient acceptability 122 . However, adult insects are rarely used for feeding because ageing decreases the amount of protein and increases the amount of fat and less digestible parts 123 . The content and quality of chitin varies through development, with sheddings and cocoons being most rich in chitin 124 .…”

“…122 However, adult insects are rarely used for feeding because ageing decreases the amount of protein and increases the amount of fat and less digestible parts. 123 The content and quality of chitin varies through development, with sheddings and cocoons being most rich in chitin. 124 In prepupae and cocoons, chitin is more crystalline; its higher thermal degradation temperatures are connected with more linkages between molecules and their higher resistance in larvae and sheddings.…”

Insects in Pet Food Industry—Hope or Threat?

“…This factor overestimates the protein content due to the presence of non-protein nitrogen in insects. In a study [ 35 ], the specific Kp of 4.75 was calculated for the Hermetia illucens , and a Kp of 4.67 was calculated for Tenebrio molitor , while Homska et al [ 36 ] obtained a Kp of 5.12 for Hermetia illucens larvae meal and a Kp of 4.91 for Tenebrio molitor larvae meal. When using insects as an alternative protein source, care should be taken to avoid overestimating the protein content due to the presence of non-protein nitrogen.…”

“…When using insects as an alternative protein source, care should be taken to avoid overestimating the protein content due to the presence of non-protein nitrogen. To avoid overestimating the protein content of insects, the authors of these studies proposed to use the above-mentioned Kp [ 35 , 36 ]. What is more, the protein content of an ingredient should be calculated from the sum of individual amino acids [ 37 , 38 ].…”

Long-Term Dietary Fish Meal Substitution with the Black Soldier Fly Larval Meal Modifies the Caecal Microbiota and Microbial Pathway in Laying Hens

“…Therefore, the pertinency of BSF to food recycling, waste management, and feed processing has been extensively explored. Some evidence suggests that using BSF larval (BSFL) meal in aquaculture feed improves the gut and skin mucosal immune responses in fish, consequently contributing to better growth performance [ 5 , 6 ]. Studies have also explored the potential of BSFL meal as an alternative protein ingredient in pig feed without adverse effects on growth performance and gut morphology [ 7 ].…”