Reference intervals for haematological and serum biochemical indices in vulnerable Himalayan Snow trout, Schizothorax richardsonii, inhabiting the Indus tributary of Ladakh Trans-Himalayan region, India

Haemato-biochemical parameters serve as an excellent marker of the overall health condition of fish species and their reaction to biological and ecological factors. The main goal of this study was to determine the sex-specific reference values for blood and serum biochemistry parameters in Schizothorax richardsonii, an economically valuable fish species found in the Indus tributary of Ladakh Trans-Himalayan region. To get the necessary data, blood samples were obtained from the fish population between the months of May and October in the years 2021 and 2022. Throughout the duration of the investigation, a total of 180 samples were collected, consisting of 100 males and 80 females. Several parameters, including haemoglobin (Hb), red blood cell (RBC) and white blood cell (WBC) counts, packed cell volume (PCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), mean corpuscular volume (MCV), total protein, albumin, glucose, urea and cholesterol, were examined. The reference intervals were determined employing Reference Value Advisor v2.1 software. The haematological and biochemical findings revealed statistically significant differences (p < 0.05) between males and females. Males had considerably (p < 0.05) higher levels of Hb, RBC, PCV and serum glucose than females, who, in turn, had significantly (p < 0.05) higher levels of WBC and serum cholesterol. However, there were no statistically significant differences (p > 0.05) seen in the values of MCH, MCHC and MCV between males and females. The study presents significant data on the haematological and serum biochemical reference intervals of S. richardsonii. This information may prove useful in the monitoring of the species’ metabolic balance, the assessment of its current state of health and the conduct of future comparative research.