2022, Homska, Natalia, Kowalska, Joanna, Bogucka, Joanna, Ziółkowska, Ewa, Rawski, Mateusz, Kierończyk, Bartosz, Mazurkiewicz, Jan

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.

2025, Rawski, Mateusz, Mazurkiewicz, Jan, Mikołajczak, Zuzanna, Kierończyk, Bartosz, Skrzypczak, Paula, Szymkowiak, Piotr, Józefiak, Damian

The microbiota of the gastrointestinal tract (GIT) plays a crucial role in the development, lifespan, physiology, barrier functions and immunity against pathogens in fish. One of the significant causes of fish mortality in production systems, which also generates huge financial losses, is pathogenic dieseases. Consequently, effectively managing disruptions in the microbiota could play a crucial role in mitigating economic losses across the sector. It was investigated the effect of an alternative raw material increasing inclusion—full‐fat Hermetia illucens larvae meal on the composition of the gastrointestinal microbiome of Atlantic salmon. Thus, five experimental feeds were prepared: a control diet (CON) without the addition of black soldier fly full‐fat meal (BSFM) and with 30% fish meal (FM); BSFM5, with 5% addition of full‐fat BSFM and 27.1% FM; BSFM10, with 10% full‐fat BSFM and 24.3% FM; BSFM15, with 15% addition of full‐fat BSFM and 21.3% FM; and BSFM20, with 20% addition of full‐fat BSFM and 18.6% FM. After 60 days of growth experiment on Atlantic salmon presmolts, the contents of two sections of the GIT, proximal and distal, were gently sampled and subjected to next‐generation sequencing (NGS) to analyse the microbial populations. No significant differences were observed in the microbial compositions of the groups, irrespective of the intestinal section analysed. In the proximal and distal intestine, the CON group exhibited the highest number of distinct phyla. Increasing the inclusion of BSFM in the diet led to a reduction in the abundance of specific phyla. Similar results were noted at genus level. The BSFM5 and BSFM10 groups showed increase number in Enterococcus, while the Lactobacillus population were maintained at a high level. Due to abovementioned changes as well as the increased share of Bacilli populations, it may be concluded that up to 20% BSFM shares may have positive microbiota‐modulating effects. Thus, BSFM may be considered not only as a nutrient source but a functional feed material in fish diets also, due to its prebiotic effects observed in the study.

2023, Mikołajczak, Zuzanna, Mazurkiewicz, Jan, Rawski, Mateusz, Kierończyk, Bartosz, Józefiak, Agata, Świątkiewicz, Sylwester, Józefiak, Damian

Abstract Black soldier larva meal (BSFM) seems to be a competitive protein and fat source for widely used fish meal (FM) and fish oil. Because of the still present problem of overfished seas and oceans for feed purposes, even a low substitution of the mentioned feed materials could have a positive impact on the environment. Due to the specificity of salmon metabolic processes, with particular attention to smoltification and the various requirements for nutrients related to individual stages, it is important to implement similar dietary inclusion levels of innovative feed materials in different life stages of Atlantic salmon. Thus, a holistic approach was undertaken in the cycle of two studies carried out: on fries and pre-smolts. This study aims to evaluate the effect of FM replacement by full-fat BSFM in Atlantic salmon pre-smolt diets on growth performance, feed utilization, somatic indices, histomorphology of intestines, colorimetric assessment and raw meat quality, as well as environmental sustainability. The following groups were applied: CON – without addition of full-fat BSFM and with 30% FM; BSFM5 – with 5% addition of full-fat BSFM and 27.1% FM; BSFM10 – with 10% full-fat BSFM and 24.3% FM; and BSFM15 – with 15% addition of full-fat BSFM and 21.3% FM. The present study showed satisfactory results of BSFM inclusion up to 15% as a replacement for FM in feeds for Atlantic salmon pre-smolts. The present study showed that BSFM is a suitable feed material for Atlantic salmon proper diet balancing and may be used to decrease FM content. The semi-technical application of BSFM containing diets confirmed their effectiveness during the growth phase of Atlantic salmon. According to our results, BSFM can be recommended as an alternative feed component in Atlantic salmon pre-smolt nutrition at levels up to 15%. Simultaneously, insect inclusion significantly improved the environmental sustainability of the rearing process.