No abstract

No abstract

Background: Lactococcus garvieae is one of the most important risk factors in the rainbow trout culture. Therefore, the purpose of this study was to identify and detect strains isolated from rainbow trout suspected of having Lactococcus garvieae using biochemical characteristics and PCR and determination of the degree of severity of isolated strains. Methods: In this study, the cause of lactococcosis in selected rainbow trout farms in Kohkilooieh and Boyerahmad province was assayed. Gram-positive and catalase-negative bacterial isolates were first obtained from selected trout fish farms using conventional biochemical tests and PCR assay. The 10-day LD 50 method (concentration causing 50% mortality in 10 days) was used to determine the severity of the isolated bacteria. Results: One bacterial isolate was detected from all sampled fish which confirmed as Lactococcus garvieae using a specific PCR assay based on the 16S rDNA gene by producing a single band of 1107 bp. Analysis of the rate of mortality showed that the 10-day LD 50 was 4.6 × 10 5 CFU/fish. The results of this study showed that isolated bacteria had high severity for rainbow trout. The presence of bacteria in internal organs of suspected fish showed a severe systemic infection in challenged fish. Antibiogram assay also indicated that the isolated Lactococcus garvieae were resistant to some mostly used antibiotics in rainbow trout. Conclusions: According to current research, it can be concluded that the condition of lactococcosis in the studied area is not suitable, and despite the presence of disease, there is no proper action to control and prevent the disease. Unfortunately, isolated bacteria from the studied area have a very high severity compared to bacteria isolated from other regions of the country or other countries. Therefore, further investigation is needed to determine the cause of this difference and possibly in the design of the vaccine.

No abstract

BackgroundHexavalent Chromium (Cr (VI)) compounds are extremely toxic and have been demonstrated to induce nephrotoxicity associated with oxidative stress in humans and animals. The wide environmental distribution of these agents lead to an increase interest of preventive effects of its adverse effects. ObjectivesThe propose of the present study was to determine the potential protective effects of simvastatin (SIMV) on Cr (VI)-induced nephrotoxicity in rat. Materials and MethodsForty-eight adult male Wistar rats (180-220 g BW) were randomly assigned to eight groups (n = 6). Group one received SIMV 20 mg/kg/day. Group two was given vehicle only. Groups three, five and seven received intraperitoneally (i.p) sodium dichromate (Cr (VI)) at doses of 8, 12 and 16 mg/kg body weight. Groups four, six and eight pretreated with the 20 mg/kg SIMV 30 minutes to prior administration of Cr (VI) at doses of 8, 12 and 16 mg/kg, respectively. The experiment repeated for eight consecutive days. Twenty-four hours after the last administration, animals were killed with overdose of sodium pentobarbital. Kidney tissues were excised for measuring malondialdehyde (MDA), glutathione (GSH) and histopathological examination. ResultsChromium induced a dose dependent elevation of MDA and reduction of GSH levels. Histopathological manifestations were observed in Cr (VI)-treated rats. SIMV administration restored Cr (VI) produced biochemical and morphological changes in rat kidney. SIMV decreased MDA values and increased GSH levels in Cr (VI)-treated rats. SIMV clearly reversed the microscopic damage, demonstrating its protective effects against Cr (VI)-induced kidney injury. ConclusionsThis observation suggests that SIMV may have a protective effect against Cr (VI)-induced oxidative stress in rat kidney.