ANTIOXIDANTS AND THEIR IMPORTANCE DURING MUSCULAR EXERCISE: A REVIEW

Physiological levels of reactive oxygen species, as an essential part of the homeostatic milieu, are required for normal functioning of skeletal muscle. High levels of reactive oxygen species promote contractile dysfunction resulting in muscle weakness and fatigue, oxidative stress, apoptosis and necrosis of muscle cells. It is known that both resting and contracting skeletal muscles produce reactive oxygen species and reactive nitrogen species. The first suggestion that physical exercise results in free radical-mediated damage to tissues appeared in 1978. The newest researches investigate the mechanisms by which oxidants influence skeletal muscle contractile properties and explore how to protect muscle from oxidant-mediated dysfunction. Principal antioxidant enzymes include superoxide dismutase, glutathione peroxidase, and catalase. Numerous non-enzymatic antioxidants exist in cells within skeletal muscle fibers, the most abundant of which include glutathione, bilirubin, α-Lipoic acid , uric acid, and ubiquinones, or coenzyme Q (CoQ) andflavonoids. Dietary antioxidants are vitamins C- L ascorbic acid , vitamin A, retinol and their provitamins, carotenoids (especially β-carotene), vitamins E, tocopherol (especially a-tocoferol ), folic acid or folates. The usage of endogenous enzymatic and non-enzymatic antioxidants protects muscle from strong damaging effects caused by free radicals during acute exercise or longer term physical exercise. Scientific researches now confirm that the long-term use of antioxidants is safe and effective. The actual recommendation for physically active individuals is to ingest a diet rich in antioxidants

Meta-analysis of the efficacy of cattle hide interventions to reduce microbiological contamination in beef

Interventions at abattoir level are considered necessary to control microbiological hazards and therefore, constitute an essential and integral part of meat safety assurance systems. Cattle hide interventions can be seen as a ‘proactive’ approach in dealing with the sources of beef carcass contamination. A systematic review and meta-analysis of literature investigating the efficacy of processing interventions to control microbiological contamination in beef was performed. A total of 266 relevant studies were identified, with 113 (42.5%) judged to be at ‘low’ risk of bias, including four on hide cleanliness assessment and seven on hide interventions where extractable data were available for meta-analysis. The summary effects from a random-effect meta-analysis model show a consistent reduction for all indicator microorganisms (aerobic colony counts (ACC), Enterobacteriaceae counts (EBC) and generic E. coli) on hides and resulting carcasses, when clean cattle are compared with dirty cattle. Least-squares mean reductions (log CFU/cm2) on carcass surfaces were 0.9 (95% confidence interval (CI): 0.54-1.26) for ACC, 0.71 (0.36-1.05) for EBC and 0.75 (0.65-0.85, only one study) for E. coli. There was an insufficient number of hide intervention studies on hide clipping, bacteriophage treatment and some chemical washes to draw firm conclusions on their efficacy. The meta-regression effect revealed that hide water wash may have some limited protective effect in reducing STEC prevalence on hides, although the high heterogeneity found in the summary effects indicates that the intervention results differ substantially (relative risk (RR) 0.85; 95% CI: 0.66-1.09). The mean reduction effect in reducing levels of aerobic bacteria on hides was also low, 0.6 log CFU/100 cm2, questioning the usefulness of hide water wash as a stand-alone intervention. Studies investigating microbial immobilisation treatment of cattle hides (shellac spray coating) showed the mean reduction effect (log CFU/cm2) on resulting beef carcasses (reduction-in-transfer) was 1.07 (95% CI: 0.29-2.43) for ACC and 0.59 (1.05-2.22) for EBC. When six controlled trials (conducted under commercial abattoir conditions), investigating shellac spray hide coating and chemical spray washes with cetylpyridinium chloride, sanitiser and sodium hydroxide, were plotted together, they showed the reduction effect on beef carcasses (log CFU/cm2) of 1.09 (95% CI: 0.65-1.53) for ACC and 0.81 (0.28-1.35) for EBC. The results indicate that cattle hide interventions are efficacious in controlling microbial contamination on beef carcasses. However, the high heterogeneity found in the summary effects indicates that the intervention results differ substantially and more research is needed

Salmonella in wild boars (Sus scrofa): Characterization and epidemiology

The large study on Salmonella spp. in the population of wild boars from twelve hunting estates in the South-West Vojvodina, Serbia was conducted with the aim to investigate the prevalence of Salmonella spp. in wild boars and to trace Salmonella sources. The hunting estates had similar epidemiological characteristics, i.e. lowland regions with an intensive management system of wild boars. The prevalence of Salmonella in wild boars was determined and the examination of molecular similarities of strains isolated from wild boars and domestic animals (pigs and poultry from nearby farms) was performed. The total number of 425 wild boars (25.3% of total population), shot on official hunts, were sampled (425 feces and 425 mesenteric lymph nodes samples) and examined by standard ISO protocols. Subtyping of the isolates was performed and compared by Pulsed-field gel electrophoresis (PFGE). The Salmonella prevalence in the fecal samples was 3.1% and in the lymph nodes was 0.2%. Salmonella Enteritidis was the most dominant serotype. A high molecular similarity was found between Salmonella isolates from wild boars and domestic animals. The proximity of communities and domestic animals, as well as improper removal of animal waste were identified as important epidemiological factors which significantly affect the epidemiology of Salmonella in wild boars from lowlands