Oxidative Stress Response of Honey Bee Colonies (Apis mellifera L.) during Long-Term Exposure at a Frequency of 900 MHz under Field Conditions.

In this study, oxidative stress and lipid peroxidation in honey bee larvae, pupae and the midguts of adult bees were investigated during a one-year exposure to radiofrequency electromagnetic fields (RF-EMFs) at a frequency of 900 MHz under field conditions. The experiment was carried out on honey bee colonies at three locations with electric field levels of 30 mV m-1, 70 mV m-1 and 1000 mV m-1. Antioxidant enzymes, glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS) as indicators of lipid peroxidation were measured spectrophotometrically. The GST activity within the same developmental stage showed no significant differences regardless of electric field level or sampling time. The highest GST activity was found in the pupae, followed by activity in the larvae and midguts. Both CAT activity and TBARS concentration were the highest in the midguts, regardless of field level and sampling time. The larvae showed a significantly higher TBARS concentration at the location with an electric field level of 1000 mV m-1 compared to the locations with lower levels. Our results show that RF-EMFs at a frequency of 900 MHz can cause oxidative stress in honey bees, with the larval stage being more sensitive than the pupal stage, but there was no linear relationship between electric field level and effect in any of the developmental stages.

Effect of RNF4-SacII gene polymorphism on reproductive traits of Landrace × Large White crossbred sows.

The aim of the present study was to investigate whether and to what extent the RNF4-SacII gene polymorphism influences reproduction performances in hyperprolific sow lines. The study involved 101 Landrace x Large White crossbred sows, with 461 records collected on the following reproductive traits: Total Number of piglets Born per litter (TNB), Number of piglets Born Alive per litter (NBA), Number of StillBorn piglets per litter (NSB), piglet Pre-Weaning Mortality (PWM) and Number of piglets at Weaning per litter (NW). The least square method with the GLM procedure in SAS with eight effects was used to pursue the data analysis. Study results revealed that TT homozygotes and TC heterozygotes had a significantly higher (p < .05) NW than CC homozygotes for the life-span performance in all parities and first parity analysed. In the fourth parity analysed, TNB and NBA in TC genotype were significantly higher (p < .05) as compared with TT genotype. Based on the life-span performance, significant effect (p < .05) was recorded for order of parity on TNB, NBA and NW, for farrowing season on TNB and NSB, and for lactation length on PWM. In the second parity, significant effect (p < .05) was recorded for sire of boar on NSB and for gestation length on TNB. Only in the fourth parity, significant effect (p < .05) of RNF4 gene was observed on NBA. There was significant additive effect (p < .05) of the RNF4 gene polymorphism identified on NW in all parities analysed, and significant additive and dominance effects (p < .05) on NSB in the third parity analysed. In conclusion, additional research on related production pig genotypes is necessary to elucidate the effect of RNF4 gene mutation on reproductive traits.

A New Method of Assessing Sheep Red Blood Cell Types from Their Morphology.

Data concerning the morphometric parameters of sheep red blood cells (RBCs) obtained using computer-assisted image analysis have not yet been investigated, and there are no data on any analyses of ovine RBC subpopulations based on their morphometric parameters. The aims of this study are to determine the values of RBC haematological and morphometric size and shape parameters, to form groups according to the obtained values of haematological parameters; to determine the differences in RBC morphometric parameters between the formed groups, and to determine RBC subpopulations and their respective proportions in the formed groups. Thirty-six blood samples were collected from the jugular vein of clinically healthy Lika pramenka sheep, aged between 2 and 5 years. Haematological parameters including haemoglobin (HGB), haematocrit (HTC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and RBC distribution width were analysed using a haematology analyser. Haematological parameters were categorized into two groups: those with lower values or values below the physiological range (Groups 1) and groups with higher values or values above the physiological range (Groups 2). Morphometric parameters of RBCs were determined from stained blood smears using SFORM, a computer-assisted program. Significantly higher values of RBC area, outline, convex, minimal and maximal radius, as well as length and breadth were established in Groups 2 compared to Groups 1 of HGB, HCT, MCV, MCH, and MCHC, respectively. Based on the morphometric parameters of RBCs, three RBC subpopulations were obtained using principal component and cluster analysis: ES 1-the smallest and most elongated RBCs, ES 2-the biggest and most rounded RBCs, and ES 3-average size and shape RBCs. Significantly higher proportions of ES 2 and ES 3 subpopulations, as well as a significantly lower proportion of ES 1 subpopulation, were established in Groups 2 compared to Groups 1 of HGB, HTC, MCV, and MCH, respectively. It can be concluded that ovine RBC subpopulations, based on their morphometric parameters, can be obtained by using computer-assisted image analysis of RBC morphometry and multivariate statistical methods, including principal component and cluster analysis. RBC morphometry, including classification into subpopulations, could serve as a basis for future possibilities in the diagnostic interpretation of anaemic syndromes in veterinary medicine, especially in normocytic, macrocytic, and microcytic anaemias in sheep.

The effects of monthly air temperature and rainfall variations on the reproductive performance and lambing distribution of the Jezersko-Solcava sheep.

The aim of this study was to investigate the effects of monthly air temperature and rainfall variations on the reproductive performance and lambing distribution of the Jezersko-Solcava breed in northwestern Croatia during 7 years period from 2010 until 2016. At 11 medium-scale sheep farms, the sheep were kept on a pasture in a semi-intensive environment with access to the stables. The anomalies of rainfall observed on a monthly basis during monitoring were statistically significant. Non-parametric test showed that the percentages of lambing differ among the months during the year (P = 0.0001). By using regression analysis, it was found that the percentages of pregnant sheep were linearly associated with the sequential number of the month. The seasonal distribution of lambings were 53.85% of ewes delivered in winter (n = 1296), 21.13% in spring (n = 509), 8.91% in summer (n = 215) and 16.11% in autumn (n = 387). Sexual activity was lowest during spring and early summer (from March to May) with a peak from the end of July to October. The conception rate during year 2011 was significantly lower (89.74%), and the litter size was the lowest (1.05) than in other years of the observation. Average conception rate was 92.85% and average litter size 1.21. Despite being a seasonally polyoestrous, the distribution of matings and lambings of this breed of sheep was not uniform throughout the seasons. There were established a positive or negative correlations between the air temperature and rainfall precipitation variations with tested reproductive performances of Jezersko-Solcava breed sheep in the Northwestern part of Croatia.

Differences in seminal plasma and spermatozoa antioxidative systems and seminal plasma lipid and protein levels among boar breeds and hybrid genetic traits.

The objectives of this study were to determine the influence of breed and hybrid genetic traits of boars on lipid and protein concentrations and antioxidative system variables in seminal plasma (SP) and spermatozoa and their correlations with semen quality variables. Semen samples from 27 boars: Swedish Landraces (SL), German Landraces (GL), Large Whites (LW), Pietrains (P) and Pig Improvement Company hybrids (PIC-hybrid), aged from 1.5 to 3 years old, were collected. SP was spectrophotometrically analyzed to determine total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triacylglycerol (TAG), total protein (TP), albumin, and zinc concentrations. The antioxidative system in SP and spermatozoa was established spectrophotometrically by determining total antioxidative status (TAS), total superoxide dismutase (TSOD) and glutathione peroxidase (GSH-Px) parameters, as well as copper-zinc superoxide dismutase (CuZnSOD) and manganese superoxide dismutase (MnSOD) activity in spermatozoa. The hybrid boars had higher (P<0.05) SP concentrations of: TC, LDL-C and TAG than P and GL; HDL-C than P, GL and SL; and TP than P and LW. PIC-hybrid had lower values (P<0.05) in spermatozoa of: TAS and CuZnSOD than SL; TSOD and GSH-Px than SL and P; and MnSOD than SL and LW. Differences in SP and spermatozoa antioxidative system variables and the significant differences in SP protein and lipid variables exist among boars of different breeds and hybrid. Novel data and observed differences in semen variables among boar breeds and hybrids and their correlations with semen quality parameters in this study could contribute to better assessment of boar semen quality.