Sanitary conditions of the Goliath grouper Epinephelus itajara in captivity on estuarine environment: case report

ABSTRACT This study aimed to report the sanitary conditions through the hematological analysis of grouper E. itajara reared in captivity on estuarine conditions. Seven Goliath groupers (1,881.5±1,246.03g) were captured and kept in two tanks located on estuary. After 20 days, fish were collected for morphologic and hemato-physiologic evaluation. Two fish had clinical signs such as hemorrhagic spots and loss of scale due to agonistic behavior. Blood samples were collected, and the hematological parameters (biochemical, erythrogram and leukogram) were determined. Blood cells were characterized by their size, color and shape. Univariate statistic and principal components analysis were used to identify a hematological standard between fish with or without clinical signs. Four leukocyte types were found: lymphocyte, monocyte, neutrophil and basophil. Regardless of the clinical signs the cell morphology did not present any difference among the fish. However, there is a significant correlation between erythrocyte and lactate on fish with clinical signs. Thus, agonistics encountered among the fish is a stressing factor in captivity conditions making it necessary to have adequate management related to the size of fish and stocking density.

摘要
本研究旨在通过对河口圈养环境下养殖的伊氏石斑鱼（*Epinephelus itajara*）开展血液学分析，以报道其卫生健康状况。研究共捕获7尾伊氏石斑鱼（体重1881.5±1246.03g），将其饲养于河口区域的2个养殖池内。饲养20天后，采集实验鱼进行形态学及血液生理学指标检测。其中2尾鱼因争斗行为出现出血斑、鳞片脱落等临床症状。采集血液样本后，测定了其血液学指标（包括生化指标、红细胞相指标及白细胞相指标），并通过细胞大小、色泽及形态对血细胞进行分类鉴定。采用单变量统计及主成分分析法，对比分析出现临床症状与未出现临床症状的实验鱼之间的血液学特征差异。共鉴定出4类白细胞：淋巴细胞、单核细胞、中性粒细胞及嗜碱性粒细胞。无论是否出现临床症状，实验鱼的血细胞形态均无显著差异，但在出现临床症状的实验鱼中，红细胞指标与乳酸水平存在显著相关性。综上，养殖过程中鱼类间的争斗行为是圈养环境下的应激源，因此需针对鱼体规格及放养密度制定合理的养殖管理方案。