The employment of natural substances such as beehive products with a preventive and therapeutic purpose has been a widespread custom since ancient times. In this investigation, the antibacterial activity of 41 honey samples from different Ukraine regions has been evaluated. For each honey, melissopalynological and physico-chemical analysis were performed in order to determine botanical origin, pH, glucose and fructose contents and free acidity. So, antibacterial activity against Staphylococcusaureus CCM 4223, Listeria monocytogenes ATCC 7644, Salmonella enterica serovar Typhimurium CCM 3807 and Escherichia coli ATCC 25922 was assessed through the determination of MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values by the microdilutions method. The results show that the most susceptible bacterial strain was L. monocytogenes. Its growth was inhibited at a honey concentration ranging from 0.094 to 0.188 g/mL. The most resistant bacterial strain was S. aureus. As concerns MBC values, L. monocytogenes was the most susceptible bacteria, while S. aureus was the most resistant. Helianthus spp. honeys was the most effective against all tested bacterial strains, followed by Robinia spp. and multifloral honeys. Promising results for MIC tests have been found for Brassica spp.

The effects of veterinary drugs, dietary supplements and non-protein amino acids on the European honey bee (Apis mellifera ligustica Spinola, 1806) ventriculum microbial profile were investigated. Total viable aerobic bacteria, Enterobacteriaceae, staphylococci, Escherichia coli, lactic acid bacteria, Pseudomonas spp., aerobic bacterial endospores and Enterococcus spp. were determined using a culture-based method. Two veterinary drugs (Varromed^® and Api-Bioxal^®), two commercial dietary supplements (ApiHerb^® and ApiGo^®) and two non-protein amino acids (GABA and beta-alanine) were administered for one week to honey bee foragers reared in laboratory cages. After one week, E. coli and Staphylococcus spp. were significantly affected by the veterinary drugs (p < 0.001). Furthermore, dietary supplements and non-protein amino acids induced significant changes in Staphylococcus spp., E. coli and Pseudomonas spp. (p < 0.001). In conclusion, the results of this investigation showed that the administration of the veterinary drugs, dietary supplements and non-protein amino acids tested, affected the ventriculum microbiological profile of Apis mellifera ligustica.

Fishmeal (FM) is still the most important protein source in aquafeeds. However, due to the reduction of wild fish stocks used for FM production, its manufacturing it is now unsustainable. Insect meal represents a valid alternative to FM, due to the low carbon footprint of its production and its high nutritional value. The aim of this study was to investigate the potentials of replacing FM with black soldier fly (Hermetia illucens) meal (HIM) in aquafeeds, using zebrafish as the animal model. Four diets were formulated with increasing HIM/FM replacement rate (the control diet contained 20% FM). Mortality rates, growth performances, and feed consumptions were measured, and fish intestine samples were collected for histological and enzymatic analysis. After 49 days, all groups almost tripled their initial body weight (cumulative body weight gain ranged between 143.9 and 155.2 mg), and no statistically significant differences among treatments were observed in relation to growth performances and histological traits. Contrarily, trypsin, alkaline phosphatases, and alpha amylase–glucoamylase activities were significantly reduced when the FM replacement rate was increased. In conclusion, HIM may represent an alternative to FM, since no adverse effects were observed when it was included up to 20% in the zebrafish diet, even when replacing 100% of the FM.

Honeybee pathogens have an important role in honeybee colony mortality and colony losses; most of them are widely spread and necessitate worldwide solutions to contrast honeybee’s decline. Possible accepted solutions to cope with the spread of honeybee’s pathogens are focused on the study of experimental protocols to enhance the insect’s immune defenses. Honeybee’s artificial diet capable to stimulate the immune system is a promising field of investigation as ascertained by the introduction of 1,3-1,6 β-glucans as a dietary supplement. In this work, by collecting faecal samples of honeybees exposed to different dietary conditions of 1,3-1,6 β-glucans (0.5% and 2% w/w), it has been possible to investigate the Deformed wing virus (DWV) viral load kinetic without harming the insects. Virological data obtained by a one-step TaqMan RT-PCR highlighted the ability of 1,3-1,6 β-glucans to reduce the viral load at the 24th day of rearing. The results indicated that the diet supplemented with 1,3-1,6 β-glucans was associated with a dose-dependent activation of phenoloxidase. The control group showed a higher survival rate than the experimental groups. This research confirmed 1,3-1,6 β-glucans as molecules able to modulate honeybees’ defense pathways, and this is the first report in which the kinetic of DWV infection in honeybee faeces has been monitored by a RT-qPCR.

Royal Jelly is a nutrient secretion of nurse bees and a high interest functional food in human nutrition. Very little information is available on its chemical composition integrity and enzymatic activity during shelf life and assessment of new freshness markers are desirable for its conservation. In this study, the activity of glucose oxidase, five proteases and two antioxidant enzymes in refrigerated and frozen Royal Jelly for different storage times was preliminary investigated. Refrigeration determined a significantly reduction in glucose oxidase and carboxypeptidase A-like activity in Royal Jelly after one year of storage while no differences were recorded in the activity of these enzymes in frozen samples. After one year of storage glucose oxidase and carboxypeptidase A-like activity resulted higher in frozen samples frozen than in refrigerate ones. Results obtained suggest that the activities of these enzymes may be good markers of Royal Jelly freshness within 1 year at refrigeration condition. Freezing could be a valid alternative storage method to ensure a higher preservation of glucose oxidase and carboxypeptidase A-like activities for at least 1 year. Further investigation to determine the timing of glucose oxidase inactivation/degradation under refrigerated conditions and the enzymatic activity trend under prolonged frozen conditions are desirable.

The effects of dietary supplementation of tannins mix (quebracho and chestnut) in rabbit diet were evaluated for productive performances, health parameters and digestibility in order to quantify their practical utilisation in the rearing system. One-hundred and twenty Martini group hybrid rabbits of 30 days old were fed four different diets for 60 days. The diets were formulated as: basal diet (negative control, C), basal diet supplemented by 0.3% of tannins mix (T0.3), basal diet supplemented by 0.6% of tannins mix (T0.6) and basal diet supplemented with coccidiostat (positive control, CC). Live performances did not show any significant differences, moreover, no significant differences were observed for all carcase traits except for gastrointestinal tract (p = .015, lowest values for T0.3 diet). Also, digestibility of the feed and faecal microbial load was not influenced by tannins addition. Slight differences between the diets were detected in catalase and glutathione peroxidase concentrations in plasma, as a common trend was revealed with higher values of C than the other diets. From an economical point of view, T0.3 diet showed to be more profitable than CC and T0.6. Tannins addition might be taken into account as potential feed additive in rabbit feeds, as it does not affect negatively the productive performances, digestibility and induce a slight increase of antioxidant status.