The estrogenic mycotoxin zearalenone (ZEN) is a common contaminant of animal feed. Effective strategies for the inactivation of ZEN in feed are required. The ZEN-degrading enzyme zearalenone hydrolase ZenA (EC 3.1.1.-, commercial name ZENzyme^®, BIOMIN Holding GmbH, Getzersdorf, Austria) converts ZEN to hydrolyzed ZEN (HZEN), thereby enabling a strong reduction in estrogenicity. In this study, we investigated the efficacy of ZenA added to feed to degrade ZEN in the gastrointestinal tract of three monogastric animal species, i.e., pigs, chickens, and rainbow trout. For each species, groups of animals received (i) feed contaminated with ZEN (chickens: 400 µg/kg, pigs: 200 µg/kg, rainbow trout: 2000 µg/kg), (ii) feed contaminated with ZEN and supplemented with ZenA, or (iii) uncontaminated feed. To investigate the fate of dietary ZEN in the gastrointestinal tract in the presence and absence of ZenA, concentrations of ZEN and ZEN metabolites were analyzed in digesta of chickens and rainbow trout and in feces of pigs. Upon ZenA administration, concentrations of ZEN were significantly decreased and concentrations of the degradation product HZEN were significantly increased in digesta/feces of each investigated animal species, indicating degradation of ZEN by ZenA in the gastrointestinal tract. Moreover, upon addition of ZenA to the diet, the concentration of the highly estrogenic ZEN metabolite α-ZEL was significantly reduced in feces of pigs. In conclusion, ZenA was effective in degrading ZEN to HZEN in the gastrointestinal tract of chickens, pigs, and rainbow trout, and counteracted formation of α-ZEL in pigs. Therefore, ZenA could find application as a ZEN-degrading feed additive for these animal species.

This study explores the potential of utilizing black bullhead (Ameiurus melas Rafinesque, 1820), an invasive freshwater species, as a stocking fish for aquaculture. Fish were mass-removed from Ponjavica Nature Park during two periods (2018–2019 and 2020–2021), with selected individuals reared to evaluate growth, survival, and meat quality. A total of 20,145 individuals were removed in the first period (168 reared), and 15,921 in the second (120 reared). Two rearing systems—cages and recirculating aquaculture systems (RAS)—and four feed types were tested. Results demonstrated the species’ adaptability to intensive aquaculture, with good growth, resilience to high-protein diets, and tolerance to high stocking densities. Cage systems generally showed superior growth performance, while RAS produced higher survival rates. Both systems achieved favorable feed conversion ratios. Meat analysis revealed optimal levels of polyunsaturated fatty acids (PUFAs) in RAS and cage-reared fish, enhancing the species’ nutritional value for human consumption. These findings demonstrate the feasibility of repurposing black bullhead as a sustainable aquaculture resource. This dual-purpose approach addresses ecological concerns while offering economic benefits through increased fish production and affordable, nutritious food availability. Further technological development is needed to optimize production systems for broader implementation.

Stanković Marko B, Doktorska disertacija, Univerzitet u Beogradu, Poljoprivredni fakultet, Beograd 2013, Odbranjena 21.06.2013., Jezik srpski - latinica

The combination of untreated water supply with high stocking density of fish can lead to the occurrence of diseases and/or parasites in fish, and any stress experienced by fish can cause alterations in vital organs. The aim of this research was a comparative analysis of carp gill histology, collected during the spring of 2024 from three commercial and one experimental fish farm. The water supply of these ponds is from large lowland rivers, while a pond with water supply from an artesian well was used as a control. Histological changes in carp gills were examined as potential indicator of stress.

In order to create a selection programme aimed at improving the production characteristics of rainbow trout, broodstocks from eight fish farms in the Republic of Serbia were collected in 2010. The spawning of broodstocks, hatching of eggs, and rearing of offspring from different families of known parentage, until marking at five months of age, were carried out in individual tanks under strictly controlled conditions. After tagging, the fish were reared in a flow-through system on a commercial fish farm, where their growth was further monitored. The study of the phenotypic variability and heritability coefficients of the broodstock was carried out on a sample of 6565 individuals. The body weights and total lengths of the individuals were measured at five, 12, 24, and 36 months of age. Factors such as the year of spawning and sex proved to be highly statistically significant for the observed growth traits, while the heritability values of the analysed traits were moderate to high (0.22–0.68). The estimated heritability values provide an excellent basis for the continuation of the selective breeding programme, which will ultimately lead to the improvement of salmonid aquaculture and the profitability of rainbow trout production in the Republic of Serbia. (Submitted 11 December 2024; Accepted 16 July 2025; Published 20 August 2025)