Glucose determination in fish plasma by two different moderate methods

Abstract

Teleost fish include many different species, having a large economic and environmental impact. Glucose is a key source of energy for most vertebrate organisms. Fish as well as mammals maintain a specific level of blood sugar – glycaemia, which is influenced by multiple factors such as hormone production, diet, and temperature. Therefore, it is a useful indicator for scientists who need to check the immediate state of an organism. The most frequently used method of measuring glycaemia in farmed fish is spectrophotometry; however, this method is often inconvenient for field experiments. Here we report that basic spectrophotometry using oxidation of blood beta D-glucose by glucose oxidase (used in laboratory conditions) can be easily substituted with portable glucometer measurements, primarily designed for human samples. The possibility of use outside the laboratory and its small sample volume demands make this method very useful. Field studies often require fast sample processing and conditions of measurement are limited. Using the glucometer is a simple and elegant option. We tested 74 blood plasma samples (29 males, 45 females) of tench (Tinca tinca) both spectrophotometrically and using the human glucometer. Our results show a significant linear correlation (P < 0.001) between both methods. The main contribution of this study consists in comparability and interchangeability of results obtained from both presented methods.