نشریه تحقیقات دامپزشکی و فرآورده های بیولوژیک
سال سی و ششم شماره 3 (پیاپی 140، پاییز 1402)

Heat stress is one of the stressors in livestock. Vitamin C has antioxidant properties and can help reduce heat stress ether. This study aimed to investigate the effect of intraperitoneal injection of vitamin V during acute heat stress on feed intake and some blood metabolites of Kermani sheep. This study was performed in Shahid Beheshti Research Station of Jiroft University under super-acute heat stress for three days. Treatments included male and female sheep divided into four treatments and five replications, so the treatments differed in sex and drug intake. The drug was injected at zero hours, and feed intake was measured at two and four hours after injection. Finally, blood samples were taken from the venous vein in the fourth hour after the drug injection. Serum samples were sent to the laboratory for analysis of blood metabolites. The results showed that intraperitoneal vitamin C injection significantly reduced feed intake (P <0.01). Albumin, cholesterol, and triglyceride metabolites were reduced (P <0.01) by vitamin C injection. However, vitamin C was reduced. There was no effect on total protein, glucose, creatine, and blood urea at the level of (P <0.05). The results showed that vitamin C reduced heat stress in sheep and improved physiological status and hormonal and blood parameters.

Helicobacter pylori infection is the most common stomach disease worldwide. Various invasive and non-invasive diagnostic methods are used to detect this bacterium, associated with limitations. The present study was conducted to evaluate the efficiency of the resonance method and the use of specific modulation frequency (SMF) compared with the histopathology diagnostic method to detect Helicobacter pylori in gastric biopsy samples of experimentally infected mice. One hundred healthy male C57BL/6 mice were included in the study and divided into the control and treatment groups. Mice of the treatment group were inoculated intragastrically with 109 colony-forming units of H. pylori (ATCC 43504) mixture or PBS after treatment with 0.2 ml of 0.2 M NaHCO3 (Merck, Germany) to neutralize gastric acidity. Mice were kept up to 28 days and examined on days 0, 7, 14, 21, and 28 using Histopathology and SMF. On day 0, only SMF could detect the H. pylori in the stomach of 60% of mice. On day 7, histopathology could detect H. pylori in 20% of mice. SMF detected all infected mice from days 7 to 28 (100%). Histopathology detected all infected mice only on day 28. Statistically significant differences were found between the two diagnostic methods on days 0, 7, 14, and 21 of the experiment (P <0.05). SMF was found to have high sensitivity and specificity for H. pylori detection in all stages of infection.

Globally, clinical mastitis (CM) is a significant disease in the dairy industry and has a tremendous economic impact because of the significantly reduced amount of milk production. Antibiotics are medicines used to treat infections, particularly those of bacterial origin. Misusing these common drugs leads to emerging resistance bacteria and public health concerns in human and animal medicine worldwide. Therefore, the use of natural alternatives with low effects is recommended. This article aims to evaluate the antibacterial activity of peptide nisin on mastitis bacteria and its synergistic effect with CLF36 peptide in vitro. Recombinant peptide nisin and CLF36 were obtained from previous research. The minimum inhibitory concentration (MIC) test was performed using the microdilution method on bacteria extracted from animal mastitis, such as Clostridium perfringens, Proteus mirabilis, Enterococcus faecalis, Salmonella typhimurium, Pseudomonas aeruginosa, and Listeria monocytogenes. This study showed that nisin and CLF36 alone had an inhibitory effect on all the studied bacteria in the 64-32 and 256-32 μg/ml concentration range, respectively. Also, the combination of nisin and CLF36 showed a general synergistic interaction for all used strains (FIC I < 0.5). This study demonstrated that combining these two peptides could reduce the risk of developing drug resistance by creating synergistic effects with a minimum concentration of each of the two peptides.