Mastitis of dairy cattle is one of the most frequently diagnosed diseases worldwide. The main etiological agents of mastitis are bacteria of the genus Streptococcus spp., in which several antibiotic resistance mechanisms have been identified. However, detailed studies addressing this problem have not been conducted in northeastern Poland. Therefore, the aim of our study was to analyze, on phenotypic and genotypic levels, the antibiotic resistance pattern of Streptococcus spp. isolated from clinical cases of mastitis from dairy cattle in this region of Poland. The research was conducted using 135 strains of Streptococcus (Streptococcus uberis, n = 53; Streptococcus dysgalactiae, n = 41; Streptococcus agalactiae, n = 27; other streptococci, n = 14). The investigation of the antimicrobial susceptibility to 8 active substances applied in therapy in the analyzed region, as well as a selected bacteriocin (nisin), was performed using the minimum inhibitory concentration method. The presence of selected resistance genes (n = 14) was determined via PCR. We also investigated the correlation between the presence of resistance genes and the antimicrobial susceptibility of the examined strains in vitro. The highest observed resistance of Streptococcus spp. was toward gentamicin, kanamycin, and tetracycline, whereas the highest susceptibility occurred toward penicillin, enrofloxacin, and marbofloxacin. Additionally, the tested bacteriocin showed high efficacy. The presence of 13 analyzed resistance genes was observed in the examined strains [gene mef(A) was not detected]. In most strains, at least one resistance gene, mainly responsible for resistance to tetracyclines [tet(M), tet(K), tet(L)], was observed. However, a relationship between the presence of a given resistance gene and antimicrobial susceptibility on the phenotypic level was not always observed.

Nisin, a lantibiotic bacteriocin, has been used for years as a natural food preservative. In addition to its antimicrobial activity, nisin also shows immunomodulatory properties, and the nisin‐producing Lactococcus lactis strain has been successfully tested as a probiotic in weaned piglets. However, the impact of nisin on porcine immune cells has not yet been explored. The objective of the present study was to examine the in vitro immunomodulatory effect of nisin on porcine peripheral blood leucocytes. The whole heparinized blood samples or freshly isolated peripheral blood mononuclear cells (PBMCs) were incubated with different nisin concentrations (0, 1.56, 3.125, 6.25, 12.5, 25 or 50 µg/ml) for 1, 24, 48 or 72 hr. Escherichia coli bacteria were used to stimulate blood phagocytes, while concanavalin A and lipopolysaccharide from E. coli were used as mitogens. Control cells remained unstimulated. MTT colorimetric assay was used to evaluate PBMCs viability and mitogenic response. Phagocyte activity and T‐cell proliferation were measured by flow cytometry. Flow cytometer was also used for immunophenotyping of T cells. Cytokine levels in the culture media were determined using commercial immunoassay (ELISA) kits. The highest concentration of nisin exhibited proliferative activity (p ˂ 0.05), stimulated interleukin‐1 beta (IL‐1β) and interleukin‐6 (IL‐6) production (both at p ˂ 0.001), and increased the percentage of CD4+CD8+ T cells (p ˂ 0.001) among unstimulated leucocytes. After cell stimulation, however, the highest nisin concentration showed antiproliferative activity (p ˂ 0.05), decreased phagocytic functions (p ˂ 0.05) and inhibited the synthesis of IL‐6 (time‐ and concentration‐dependent effect). As a typical bacterial product, nisin had a stronger impact on innate immune cells, and its effect on T cells was likely a consequence of the modulation of the activity of antigen‐presenting cells. Nisin may be a good candidate as an immunomodulator in pig breeding.

Selenium is an essential trace element in the diet of humans and domesticated animals. It is a component of more than 30 selenoproteins, which play a significant role in the body. Selenoproteins protect cells from damage inflicted by free radicals, the cause of many chronic diseases. They also participate in the metabolism of thyroid hormones, control reproductive functions and exert neuroprotective effects. In addition to its anti-proliferative and anti-inflammatory properties, selenium stimulates the immune system. The role of selenium is aided by vitamin E and sulfur-containing amino acids. Selenium deficiency contributes to pathological changes in farm animals, which incur large financial losses each year. Low selenium levels can lead to the development of nutritional muscular dystrophy, also known as white muscle disease, in lambs, kids, foals, calves and poultry from birth to 3 months of age. Selenium deficiency may also cause exudative diathesis in poultry as well as dietary necrotic liver degeneration and mulberry heart disease in pigs. Parturition problems resulting from reduced tension of the muscular layer of the uterus, postparturient paraplegia, placental retention and purulent inflammations of the uterine lining are also attributed to low selenium levels. Selenium deficiency contributes to the formation of ovarian cysts and increased embryonic mortality in the first 3-4 weeks after insemination. Selenium and vitamin E facilitate neutrophil migration to the mammary gland, and they enhance the bactericidal effects of neutrophils, thus shortening and alleviating the symptoms of clinical mastitis. Selenium poisoning is rarely encountered, and it most often results from an overdose of selenium supplements. The most common forms of selenosis are chronic selenosis, referred to as alkali disease, and acute selenosis, popularly known as blind staggers.

The purpose of this study was to investigate possible alterations in acid-base balance parameters and the coagulation profile in neonatal diarrheic calves. Twenty neonatal diarrheic and 20 clinically healthy neonatal calves aged between 1 week to 10 days were used. All blood samples were taken on the third day from the onset of diarrhea symptom. Venous blood samples were collected from each animal to determine platelet numbers, pH, pCO 2 , pO 2 , HCO 3-, BE, O 2 SAT, ctCO 2 and electrolytes (K + , Na + and Cl -). Plasma samples were collected from each animal for the measurement of prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), the concentrations of fibrinogen, D-dimer and the activity of antithrombin III (AT III). Blood pH (7.19), BE (-10.6 mmol/l), HCO 3 -(25.15 mmol/l), pO 2 (3.33 kPa), O 2 SAT (24.12 %) were significantly lower and serum concentration of K + (6.55 mmol/l) was significantly higher in diarrheic calves. These changes indicate the state of uncompensated metabolic acidosis with accompanying hyperkalemia. TT (32.05s) and APTT (39.9s) values were more prolonged in calves with diarrhea than in the control group. D-dimer (587.25 μg/l) concentrations were significantly increased while a visible drop in AT III (103.75%) activity and platelets counts (598 x10 9 /l) were observed in diarrheic group of calves. The results suggest that a consumptive type of disseminated intravascular coagulation (DIC) developed in diarrheic calves.

The aim of this study was to determine the presence of cocaine-and amphetamine-regulated transcript-like immunoreactive (CART-LI) neurons and co-localisation of CART with vesicular acetylcholine transporter (VAChT), neuronal nitric oxide synthase (n-NOS), vasoactive intestinal polypeptide (VIP), substance P (SP) and leu-enkephalin (LENK) in the enteric nervous system of the porcine gastric cardia by using a double-labelling immunofluorescence technique. CART-LI neurons were observed in the myenteric plexus (18.2±2.6%). A dense network of CART-LI nerve fibers was mainly observed in the muscular layer. CART showed co-localization mainly with VAChT, n-NOS, VIP and to a lesser degree with LENK and SP. Distribution of CART and its co-localization with other neurotransmitters suggest that this peptide plays an important role in gastric motility in the pig.