اثر تزريق داخل صفاقي ويتامين C بر درد و خيز ناشي از فرمالين و هيستامين در موش هاي صحرايي

Bacteriological study of Grass carp (Ctenopharyngodon idella) mortality in Khuzestan province

The presumptive interfere of bacterial agents in Grass carp tCt enopharyngodon idella) mortality in Khuzestan province were investigated. Three hundred Moribund fish from 20 farms with highest grass carp mortality in the last few years were taken for bacteriological study. Aller transferring to the lab, fish were dissected and bacteriological samples of some internal organs (kidney, liver and spleenjwere taken using Triptic Soy Agar (TSA) media. Isolated bacteria were identified using standard bacteriological methods. Bacterial infection was seen only in 53 fish. The bacterial species include Aeromonas hydrophila (33), Aeromonas veroni (12) and Aeromonas sobria (8). LD~ o of representative of each bacteria were calculated according to Reed and Muench to determine their pathogenicity in grass carp. Results show that A.veroni and Aiso bria are not pathogenic to grass carp but A.hydrophila was slightly pathogenic with LD ~o = 1.\ * 10 7 • Regarding the results of this study, the sever mortality in grass carp canʹt be caused by these bacterial agents primarily. Although some acromonads were isolated from moribund fish. Low proportion of infected fish to these bacteria and lack of bacterial virulence shows that the bacteria are secondary infection and more investigation should be conducted to find the real cause of mortality. Meanwhile, this is the first report of Aeromonas sobriaʹs isolation in Iran.