A digestibility trial was conducted with African catfish hybrid juveniles in order to determine the apparent digestibility coefficients (ADCs) of different nutrients. The experimental diets contained defatted black soldier fly (BSL), yellow mealworm (MW), or fully fat blue bottle fly (BBF) meals, in a 70 : 30 ratio between the control diet and the tested insect meals. The indirect method for the digestibility study was performed using 0.1% yttrium oxide as an inert marker. Fish juveniles of initial weight were distributed in 1 m³ tanks (75 fish/tank) of a recirculating aquaculture system (RAS), in triplicates, and fed until satiation for 18 days. The average final weight of the fish was . The ADCs of the dry matter, protein, lipid, chitin, ash, phosphorus, amino acids, fatty acids, and gross energy for the test ingredients and diets were calculated. A six-month storage test was carried out to evaluate the shelf life of the experimental diets, while the peroxidation and microbiological status of the diets were also assessed. The ADC values of the test diets differed significantly ( ) compared to those of the control for most of the nutrients. Altogether, the BSL diet was significantly more digestible for protein, fat, ash, and phosphorus than the control diet but less digestible for essential amino acids. Significant differences were found between the ADCs of the different insect meals evaluated ( ) for practically all nutritional fractions analyzed. The African catfish hybrids were able to digest BSL and BBF more efficiently than MW, and the calculated ADC values agreed with those of other fish species. The lower ADCs of the tested MW meal correlated ( ) with the markedly higher acid detergent fiber (ADF) levels present in the MW meal and MW diet. Microbiological evaluation of the feeds revealed that mesophilic aerobic bacteria in the BSL feed were 2–3 orders of magnitude more abundant than those in the other diets and their numbers significantly increased during storage. Overall, BSL and BBF proved to be potential feed ingredients for African catfish juveniles and the shelf life of the produced diets with 30% inclusion of insect meal retained the required quality during a six-month period of storage.

Green husks are the outer layer of walnut fruits. They form part of the agro-residues discarded away upon nut maturity in the walnut industry. Although it is not used, research studies show that green husk is a rich source of natural bioactive phytochemicals. A total of 83 individual phenolic compounds were identified in walnut husks, mainly consisting of naphthoquinones, flavonols, and hydroxycinnamic acids. There is no standard profile of phenolic compounds in walnuts; the quantity and quality of phenolic compounds vary by cultivar. Walnut extracts exhibit strong antioxidant activities and play an important role in the plant’s defence mechanisms against diseases, attacking different plant organs. The study provides a review of total phenolic content and individual phenolic compounds identified in green husks of different walnut cultivars as documented in different studies. It also explores the role and application of green husks in various industries such as traditional medicine, textile, wood, leather, beverage, and agriculture. In addition, the effects of phenolic compounds on biotic and abiotic factors are also evaluated.

A six-week experiment was carried out to test the effects of total (100%) and partial (50%) replacement of fish meal in the diet of African catfish growers with black soldier fly (B) meal, yellow mealworm (M) meal, and a 1:1 combination of both (BM) on the production and health of fish. A total of 420 fish with an average initial body weight of 200 ± 0.5 g were randomly distributed in triplicate to seven diet groups (C, B50, B100, M50, M100, BM50, and BM100, respectively). The growth performance and feed utilization of fish fed with partial or total replacement levels of FM with B were not significantly affected (p > 0.05) during the 6 weeks of feeding. In contrast, significant differences were observed between the groups fed with a diet where FM was totally replaced with M meal and the control in terms of final body weight, specific growth rate, feed conversion ratio, protein efficiency ratio, and protein productive value. Among the blood plasma biochemistry parameters, total cholesterol exhibited a significant difference (p = 0.007) between the M treatments and the control diet. The fatty acid profile of the liver was changed with respect to the long-chain polyunsaturated fatty acid content in all experimental groups. Parallel with this, the upregulation of elovl5 and fas genes in liver was found in all experimental groups compared to the control. Overall, this study shows that fish meal cannot be substituted with yellow mealworm meal in the practical diet of African catfish without compromising the growth, health and feed utilization parameters.

The impact of short-term feeding of three distinct diets containing insect meals on the intestinal microbiota of African catfish hybrid (Clarias gariepinus × Heterobranchus longifilis) juveniles was examined. The animals received experimental diets containing 30% insect meals derived from black soldier-fly larvae (BSL) (Hermetia illucens), yellow mealworm (Tenebrio molitor) or blue bottle-fly larvae (Calliphora vicina) for 18 days. The relative abundance of the Bacillaceae, the Planococcaceae and other bacteria significantly increased (p < 0.05) in the intestinal microbiota of the BSL group and also in the pooled group of the three catfish groups that received insect meals. Several strains of the Bacillales cultured from BSL feed had higher (p < 0.05) abundance in the intestinal microbiota of the BSL group compared to those of the control group. Among these Bacillales strains, a single fosB antibiotic resistance gene was identified. In the gut resistomes of both the BSL and the control catfish groups, the tetA(P), tetB(P) and lnu(C) antibiotic-resistance determinants were detected, while fosB was detected only in the BSL group. Overall, the study showed that a short-term shift to diets containing insect meals can induce significant (q < 0.05) changes in the gut microbiota of the African catfish without the development of reduced α-diversity and without the overgrowth of bacteria pathogenic to fish.

The Persian walnut (Juglans regia L.) is the most grown nut tree crop in Central Europe. The aim was to study the full Hungarian walnut assortment with a distinct early spring phenology to detect the difference in phenolic profile in their green husks. Furthermore, the relationship between the presence and concentration of phenolic compounds and the tolerance/resistance of the observed cultivars to walnut bacterial blight was investigated. Examining the samples, significant differences were found between the concentrations of the different groups of phenolic compounds. Walnut blight immunity tests were also performed to clarify the role of phenolic compounds in the nut derived from a non-irrigated orchard. The Hungarian-bred local cultivars contained phenolic compounds in higher concentrations than the domesticated ones. There was a significant correlation between the budburst, as well as the pistillate flowers’ receptivity and the concentration of juglone. Cultivars with a low concentration of phenolic compounds were the most susceptible to walnut bacterial blight, except ‘Bonifác’.

The aim of the present work was to evaluate the influence of genetic impact on the content of some characteristic secondary metabolites in tomato fruits. The study was conducted to screen 14 different tomato genotypes for antioxidant capacity and quality attributes (polyphenols, tocopherols, carotenoids, vitamin C) to select the genetic lines with high biological value, multiple disease resistance, and high yield capacity for further usage in crop improvement programs. Significant differences were found among the different hybrids and cultivation seasons for the phytochemical content of the fruits. The varieties developed by breeding to increase their resistance were found to differ significantly. During a 3-year cultivation experiment, the level of lycopene in freshly harvested fruits ranged between 10.38 and 63.23 mg.kg⁻¹ fwt for outdoor-cultivated Naik114 and Naik352, respectively. As for β-carotene, its content varied between 0.49 mg.kg⁻¹ for Unorosso and 11.66 mg.kg⁻¹ for Cherrola F1. The highest level of vitamin C (702.59 mg.kg⁻¹) was recorded for Cherrola F1, while the lowest level (1.36.86 mg.kg⁻¹) was determined in fruits of Unorosso. Neither polyphenol nor vitamin C showed positive correlation with antioxidant activity. In the three cultivation seasons, the highest concentration of polyphenols (579.19–804.12 mg.kg⁻¹ fwt) was determined in fruits of outdoor-cultivated Cherolla F1 variety. The α- and γ-tocopherol content varied between 2.56 and 18.99 mg.kg⁻¹, and 0.28 and 9.35 mg.kg⁻¹, respectively, in fresh tomato fruit. Among the newly bred resistant varieties, the ZKI114 variety was proved to have outstanding features concerning the amounts of the bioactive components.