The Dag defect is one of the primary morphological defects in sperm correlating with reduced fertility. This defect is found in the spermatozoa of many livestock species. The aim of the study was to assess the morphometry of the heads of normal sperm and sperm with the Dag defect in the semen of Duroc breeding boars. Sperm morphology was examined in ten ejaculates each from 12 Duroc boars. In total, 3,600 morphologically normal sperm and 838 sperm with the Dag defect were evaluated. The area, perimeter, length and width of the sperm head were measured and these basic morphometric parameters were used to calculate four additional shape indices characterising the sperm head, i.e. ellipticity, elongation, roughness and regularity. Sperm with this defect had markedly smaller heads, 0.32 μm shorter and 0.19 μm narrower than the heads of sperm with normal morphological structure. The heads of sperm with the Dag defect also had a 1.1μm smaller perimeter and a 2.5 μm² smaller surface area than the heads of morphologically normal sperm. The Dag defect is found in boar sperm irrespective of the age of the individual. It affects the morphology of the sperm head.

Land application of manure that contains antibiotics and resistant bacteria may facilitate the establishment of an environmental reservoir of antibiotic-resistant microbes, promoting their dissemination into agricultural and natural habitats. The main objective of this study was to search for acquired antibiotic resistance determinants in the gut microbiota of wild boar populations living in natural habitats. Gastrointestinal samples of free-living wild boars were collected in the Zemplén Mountains in Hungary and were characterised by culture-based, metagenomic, and molecular microbiological methods. Bioinformatic analysis of the faecal microbiome of a hunted wild boar from Japan was used for comparative studies. Also, shotgun metagenomic sequencing data of two untreated sewage wastewater samples from North Pest (Hungary) from 2016 were analysed by bioinformatic methods. Minimum spanning tree diagrams for seven-gene MLST profiles of 104 E. coli strains isolated in Europe from wild boars and domestic pigs were generated in Enterobase. In the ileum of a diarrhoeic boar, a dominant E. coli O112ab:H2 strain with intermediate resistance to gentamicin, tobramycin, and amikacin was identified, displaying sequence type ST388 and harbouring the EAST1 toxin astA gene. Metagenomic analyses of the colon and rectum digesta revealed the presence of the tetQ, tetW, tetO, and mefA antibiotic resistance genes that were also detected in the gut microbiome of four other wild boars from the mountains. Furthermore, the tetQ and cfxA genes were identified in the faecal microbiome of a hunted wild boar from Japan. The gastrointestinal microbiota of the free-living wild boars examined in this study carried acquired antibiotic resistance determinants that are highly prevalent among domestic livestock populations.

An effective way of preventing undesirable boar taint in pork meat caused by the presence of androstenone, skatole and indole is surgical castration of piglets. This, however, arouses growing social opposition. An alternative method of inhibiting the development of unpleasant odour is immune castration. The aim of the study was to compare the effectiveness of both methods of castration for the elimination of the compounds responsible and to assess the suitability of oral fluid for pre-slaughter predictive testing for boar taint. The research material was pooled oral fluid and fat samples taken from gilts and surgically and immunologically castrated piglets. The samples were tested with a liquid chromatography– tandem mass spectrometry method developed in this research. The compounds giving rise to boar taint were found only sporadically above the accepted limits; only one sample of oral fluid contained skatole at a concentration above 200 μg L⁻¹ and one contained indole more concentrated than 100 μg L⁻¹. Indole above the limit value was also detected in one fat sample. In none of the tested samples was androstenone found. The results indicate the similar effectiveness of both methods of piglet castration on the reduction of compounds generating boar taint. The usefulness of testing oral fluid for the ante-mortem prediction of boar taint has not been fully confirmed and further investigation is needed.

An effective way of preventing undesirable boar taint in pork meat caused by the presence of androstenone, skatole and indole is surgical castration of piglets. This, however, arouses growing social opposition. An alternative method of inhibiting the development of unpleasant odour is immune castration. The aim of the study was to compare the effectiveness of both methods of castration for the elimination of the compounds responsible and to assess the suitability of oral fluid for pre-slaughter predictive testing for boar taint.

Introduction: A novel to Europe Schmallenberg virus (SBV) causes clinical disease manifested by reproduction disorders in farm ruminants. In free-living ruminants, SBV antibodies as well as the virus were detected. Recent studies also revealed SBV antibodies in wild boars. The study investigates SBV antibodies occurring in wild boars in Poland at the peak of recent virus epidemics in the country.Material and Methods: Samples collected from 203 wild boars culled during the 2012/2013 and 2013/2014 hunting season were serologically tested using multi-species cELISA. Attempted neutralisation tests failed due to poor serum quality. RT-PCR was implemented in seropositive and doubtful animals.Results: Two samples collected from wild boar in the winter of 2013 gave a positive result in ELISA, while another two from the 2012/2013 hunting season were doubtful. No SBV RNA was detected in spleen and liver tissues.Conclusion: Low SBV seroprevalence in wild boars, despite high incidence of SBV infections occurring simultaneously in wild ruminants, suggests that boars are unlikely to be a significant reservoir of the virus in the sylvatic environment in Poland.

Introduction: The effect of two smear staining methods on the dimensions and shape of sperm cells in the semen of domestic pigs was evaluated. Material and Methods: The studies were carried out on 30 ejaculates collected from 15 boars, which included five Duroc boars, five Pietrain boars, and five hybrid Duroc × Pietrain boars. Each ejaculate was next sampled to make two microscopic slides, of which one was stained with eosin-nigrosin and the other with eosin-gentian dye. In total, 600 measurements of sperm cells were made. Each sperm was measured for the following morphometric parameters: head length, head width, head area, head perimeter, tail length, and the total sperm length. Results: Sperms measured on slides stained with eosin-nigrosin showed lower dimensions as compared with those stained with the eosin-gentian dye method. Sperm stained with eosin-nigrosin had shorter and narrower heads than sperm stained with eosin-gentian dye. The method of staining, therefore, affected not only the dimensions of the sperm, but also the proportions of the dimensions defining the shape of the sperm. Conclusions: The size and shape parameters in porcine sperm may take on different values depending on the method of semen staining. Sperm cells stained with eosin-nigrosin are smaller than the sperm stained with eosin-gentian dye. The sensitivity of the sperm to the type of dye used for the fixation may be associated with genetic factors.

Determination of sperm concentration and morphology in ejaculate is essential in evaluating fertility. Sperm shape and dimensions may depend on their concentration in ejaculate. The aim of the study was to evaluate the dependence of Hypor boar morphological and morphometric sperm characteristics on concentration in ejaculate. The study was conducted on 120 ejaculates from 12 Hypor boars. Depending on sperm concentration, they were put into three groups: low, medium, and high. Ejaculate sperm concentration was determined with the photometric method. Slides were prepared from semen samples which were evaluated for the morphology of spermatozoa. The preparations for morphological analyses were by the eosin-gentian staining method. As the sperm concentration in the ejaculate increased, the length, perimeter, and area of the sperm heads also did. In the ejaculates with higher sperm concentration the sperm heads were rounder. The ratios of head dimensions to tail length or total length were the highest in the sperm from ejaculates with the highest concentrations. The highest percentage of morphologically abnormal sperm was noted in ejaculates with low concentrations. The dimensions and shape of sperm depend on the sperm concentration in the ejaculate. In ejaculates with the highest concentrations, the sperm have larger dimensions. Sperm concentration affects the frequency of morphological anomalies in the spermatozoa.

Introduction: The aim of this study was to evaluate the dependence between ejaculate traits, sperm morphology, and ejaculate volume in Duroc boars. Material and Methods: The analysis involved 121 ejaculates collected from 12 Duroc boars kept in three artificial insemination centres located in central Poland. Ejaculates were collected manually at one-month intervals, over a period of 10 months. At least 10 ejaculates were collected from each boar. The material was divided by ejaculate volume and each ejaculate was assigned to one of three volume groups: 160 mL and lower, 161–200 mL, and 201 mL and higher. The ejaculates were assessed to identify the basic physical traits and determine the incidence of morphological abnormalities in the spermatozoa, specifying major and minor abnormalities. Furthermore, the morphological structure indices for the spermatozoa were also calculated. Results: In large-volume ejaculates, spermatozoa were more elongated in shape, their heads were more elongated and had the largest flagella. With an increase in the ejaculate volume, sperm concentration in the ejaculate decreased. Moreover, while the total number of sperm in the ejaculate increased, the number of insemination doses obtained from a single ejaculate were higher. Conclusion: The volume of ejaculate has little impact on the occurrence of morphological abnormalities and the size of sperm cells. Ejaculate volume is important for the shape of the sperm cells.

Introduction: The aim of this study was to evaluate the effect of lipoprotein fraction isolated from ostrich egg yolk (LPFo) on the metabolic activity of boar spermatozoa following liquid semen storage in different extenders and temperatures. Material and Methods: Boar ejaculates were extended in Androhep, Beltsville thawing solution (BTS), and Martín-Rillo and Alias (MR-A) without (control) or with the addition of LPFo and stored for three days at either 5°C or 16°C. The analysed sperm parameters included total motility (TMOT), plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), oxygen consumption, and adenosine triphosphate (ATP) production. Results: The sperm metabolic activity seemed to be higher in the LPFo-based extenders following storage for three days, irrespective of the storage temperature. Compared with the LPFo-free extenders, significantly higher (P < 0.05) sperm PMI and MMP were observed in BTS and MR-A extenders supplemented with LPFo during storage for three days at 5°C. Spermatozoa stored in the BTS-LPFo extender exhibited higher (P < 0.05) TMOT and oxygen consumption, whereas higher (P < 0.05) PMI was observed in spermatozoa stored in Androhep-LPFo and MR-A-LPFo for three days at 16°C. No significant differences (P > 0.05) in ATP content were observed between the LPFo-free and LPFo-based extenders during storage. Conclusions: Supplementation of LPFo to semen extenders had varying effects on the metabolic activity of boar spermatozoa stored at different temperatures. It can be suggested that the interactions of various components of the extenders and seminal plasma with LPFo exert beneficial effects on the sperm metabolic activity during liquid storage of boar semen.

Introduction: The effect of two smear staining methods on the dimensions and shape of sperm cells in the semen of domestic pigs was evaluated. Material and Methods: The studies were carried out on 30 ejaculates collected from 15 boars, which included five Duroc boars, five Pietrain boars, and five hybrid Duroc × Pietrain boars. Each ejaculate was next sampled to make two microscopic slides, of which one was stained with eosin-nigrosin and the other with eosin-gentian dye. In total, 600 measurements of sperm cells were made. Each sperm was measured for the following morphometric parameters: head length, head width, head area, head perimeter, tail length, and the total sperm length. Results: Sperms measured on slides stained with eosin-nigrosin showed lower dimensions as compared with those stained with the eosin-gentian dye method. Sperm stained with eosin-nigrosin had shorter and narrower heads than sperm stained with eosin-gentian dye. The method of staining, therefore, affected not only the dimensions of the sperm, but also the proportions of the dimensions defining the shape of the sperm. Conclusions: The size and shape parameters in porcine sperm may take on different values depending on the method of semen staining. Sperm cells stained with eosin-nigrosin are smaller than the sperm stained with eosin-gentian dye. The sensitivity of the sperm to the type of dye used for the fixation may be associated with genetic factors.