Blood cells and some hematological parameters of red drum (Linnaeus, 1766) in Vietnam

This research focuses on hematological characteristics, erythrocyte morphology and some biochemical parameters of red drum Sciaenops ocellatus (Perciformes: Sciaenidae), cultured in natural water environment in areas near river mouth (L1), estuaries (L2) in Ha Tinh province and coastal areas (L3) in Nha Trang city, Khanh Hoa province of Vietnam. A total of 18 speciments were examined in research, six in each location. Blood was drawn from the tail vein, using a microscope to research morphology and automated gauges to determine blood biochemical parameters. Analysis of blood samples showed that the rate of red drum’s erythrocyte morphology disorders in all three locations was quite high. The two main types of disorders were nuclear deformity and nuclear-matter distribution. Changes in erythrocyte size, shape and nuclear were related to salt concentration at culture locations. Blood hemoglobin content was stable in all three regions. Other hematological parameters such as the number of erythrocytes, blood biochemical parameters (glucose, SGOT, SGPT, urea, creatine, plasma iron, albumin, and protein) have differences among the locations, which showed the different reactions of the same species with different environmental conditions.

Isolation and determination of Vibrio spp. pathogen from hemorrhagic disease in Sciaenops ocellatus in cage culture

In this study, 18 strains of Vibrio bacteria were identified from 27 samples of Red drum fish (Sciaenops ocellatus) suffering from the haemorrhagic disease from cage culture in Vietnam. The bacterial strains were identified with the 16S rRNA sequencing method and checked for morphological, physiological, and biochemical characteristics by using the API 20E KIT. Twelve strains of V. alginolyticus, three strains of V. fluvialis, and three strains of V. orientalis were recorded. All Vibrio strains have gene similarities with those on the gene bank ranging from 98 to 100%. The biochemical characteristics of these 18 isolates were similar. These bacteria are susceptible to tetracycline and doxycycline and entirely resistant to ampicillin, amoxicillin, and erythromycin.