SummaryThe strength of the honey bee colony and the quality concerning brood production, number of worker bees and honey yield depend substantially upon the characteristics of the queen. Reproductive and productive capacities of the colony, as two important physiological qualities can depend a great deal on the age of the queen. Over the years, the laying ratio of queens could decrease depending on the age; therefore colonies headed by one-year-old queens have proven to be more efficient considering colony population and honey production than ones with older queens. Nosema ceranae infection is a possible reason for the decrease in reproductive capacities and the reduction in the honey production of infected colonies. With the help of numerous pheromones, the queen can preserve colony homeostasis, however exhausted by N. ceranae infection she might compromise the renewal of worker population. The aim of this research is to investigate the influence of N. ceranae on reproduction and productivity of honey be... ResumenLa fuerza de la colonia de abejas y la calidad en relación con la producción de cría, el número de abejas obreras y la producción de miel dependen sustancialmente de las características de la reina. La capacidad reproductiva y productiva de la colonia, son importantes cualidades fisiológicas que dependen en gran medida de la edad de la reina. Con los años, la proporción de puesta de las reinas podría disminuir en función de la edad; por lo tanto, las colonias gobernadas por reinas de un año de edad, han demostrado ser más eficaces en función de la población de la colonia y la producción de miel que las que tienen reinas mayores. La infección por Nosema ceranae es una razón probable de la disminución de la capacidad reproductiva y la reducción en la producción de miel de las colonias infectadas. Con la ayuda de numerosas feromonas, la reina puede preservar la homeostasis de la colonia, sin embargo si se agota por la infección por N. ceranae podría poner en peligro la renovación de la población de ob...

Culicoides (Diptera: Ceratopogonidae) is a genus of small biting midges (also known as “no-see ums”) that currently includes 1368 described species. They are proven or suspected vectors for important pathogens affecting animals such as bluetongue virus (BTV) and Schmallenberg virus (SBV). Currently little information is available on the species of Culicoides present in Serbia. Thus, the aim of this study was to examine species diversity, host preference and the presence of BTV and SBV RNA in Culicoides from the Stara Planina Nature Park in south-eastern Serbia. In total 19,887 individual Culicoides were collected during three nights of trapping at two farm sites and pooled into six groups (Obsoletus group, Pulicaris group, “Others” group and further each group according to the blood-feeding status to freshly engorged and non-engorged). Species identification was done on subsamples of 592 individual Culicoides specimens by morphological and molecular methods (MALDI-TOF mass spectrometry and PCR/sequencing). At least 22 Culicoides species were detected. Four animal species (cow, sheep, goat and common blackbird) as well as humans were identified as hosts of Culicoides biting midges. The screening of 8291 Culicoides specimens in 99 pools for the presence of BTV and SBV RNA by reverse-transcription quantitative PCR were negative. The biodiversity of Culicoides species in the natural reserve Stara Planina was high with at least 22 species present. The presence of C. imicola Kieffer was not recorded in this area. Culicoides showed opportunistic feeding behaviour as determined by host preference. The absence of SBV and BTV viral RNA correlates with the absence of clinical disease in the field during the time of sampling. These data are the direct outcome of a training programme within the Institutional Partnership Project “AMSAR: Arbovirus monitoring, research and surveillance-capacity building on mosquitoes and biting midges” funded by the programme SCOPES of the Swiss National Science Foundation.

West Nile virus (WNV) is a zoonotic flavivirus whose transmission cycle in nature includes wild birds as amplifying hosts and ornithophilic mosquito vectors. Bridge vectors can transmit WNV to mammal species potentially causing West Nile Fever. Wild bird migration is a mode of WNV introduction into new areas. The Danube Delta Biosphere Reserve (DDBR) is a major stopover of wild birds migrating between Europe and Africa. The aim of this study was to investigate the presence of WNV in the DDBR during the 2016 transmission season in wild birds and mosquitoes. Blood from 68 wild birds (nine different species) trapped at four different locations was analyzed by competitive ELISA and Virus Neutralization Test (VNT), revealing positive results in 8/68 (11.8%) of the wild birds by ELISA of which six samples (three from juvenile birds) were confirmed seropositive by VNT. Mosquitoes (n = 6523, 5 genera) were trapped with CDC Mini Light traps at two locations and in one location resting mosquitoes were caught. The presence of WNV RNA was tested in 134 pools by reverse transcription quantitative PCR (RT-qPCR). None of the pools was positive for WNV-specific RNA. Based on the obtained results, WNV was circulating in the DDBR during 2016.

Dietary tannin supplementation represents a potential strategy to modulate rumen fermentation and enhance lactation performance in dairy cows, though responses remain inconsistent. A 21-day feeding trial was conducted to evaluate the effect of chestnut tannin (CNT) extract on the enteric methane emissions (EME), blood metabolites, and milk production traits in mid-lactation dairy cows. Thirty-six Holstein cows were allocated to three homogeneous treatment groups: control (CNT₀, 0 g/d CNT), CNT₄₀ (40 g/d CNT), and CNT₈₀ (80 g/d CNT). Measurements of EME, dry matter intake (DMI), milk yield (MY), and blood and milk parameters were carried out pre- and post-21-day supplementation period. Compared with the no-additive group, the CNT extract reduced methane production, methane yield, and methane intensity in CNT₄₀ and CNT₈₀ (p < 0.001). CNT₄₀ and CNT₈₀ cows exhibited lower blood urea nitrogen (p = 0.019 and p = 0.002) and elevated serum insulin (p = 0.003 and p < 0.001) and growth hormone concentrations (p = 0.046 and p = 0.034), coinciding with reduced aspartate aminotransferase (p = 0.016 and p = 0.045), and lactate dehydrogenase (p = 0.011 and p = 0.008) activities compared to control. However, CNT₈₀ had higher circulating NEFA and BHBA than CNT₀ (p = 0.003 and p = 0.004) and CNT₄₀ (p = 0.035 and p = 0.019). The blood glucose, albumin, and total bilirubin concentrations were not affected. MY and fat- and protein-corrected milk (FPCM), MY/DMI, and FPCM/DMI were higher in both CNT₄₀ (p = 0.004, p = 0.003, p = 0.014, p = 0.010) and CNT₈₀ (p = 0.002, p = 0.003, p = 0.008, p = 0.013) cows compared with controls. Feeding CNT₈₀ resulted in higher protein content (p = 0.015) but lower fat percentage in milk (p = 0.004) compared to CNT₀. Milk urea nitrogen and somatic cell counts were significantly lower in both CNT₄₀ (p < 0.001, p = 0.009) and CNT₈₀ (p < 0.001 for both) compared to CNT₀, while milk lactose did not differ between treatments. These findings demonstrate that chestnut tannin extract effectively mitigates EME while enhancing lactation performance in mid-lactation dairy cows.