Clinically healthy (n=435, mean wt=48.6g) and diseased (n=154, mean wt=39.3g) juvenile Asian seabass, L. calcarifer were sampled from a commercial fish farm in Singapore for haematology. Based on clinically healthy fish, a reference interval was developed for blood glucose, haematocrit, haemoglobin, total serum protein, total white blood cell (WBC) counts, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, and relative differential WBC count, as a health assessment tool for farmed fish. Histopathology of outliers of these blood parameters showed fish had severe chronic enteritis, or were sub-clinically diseased. Significantly higher mean blood glucose, total serum protein, haemoglobin, hematocrit and lymphocytes counts were observed in clinically healthy than in diseased juvenile L. calcarifer. Diseased juvenile L. calcarifer were observed to have significantly higher mean total WBC counts and monocytes.
Keywords: Healthy, L. calcarifer, Asian seabass, blood, reference interval, subclinical, disease