Study of changes in energy metabolism parameters in brain tissue of rainbow trout (Oncorhyncus mykiss) in early life stages

For study of changes in energy metabolism of brain in rainbow trout during early life stages, some samples were collected from fish larvae and fingerlings with initial weight 1.35±0.15 during 7 months. Sample collection was randomly made in 12 stages (7 samples per every 8 days, 3 samples per every 2 weeks and 2 samples every one month). Brain tissue was dissected and transferred to nitrogen tank before analysis. The brain tissues were homogenized and the supernatant was adjusted to measurement of glycogen, glucose, lactate, lactate dehydrogenase, pyruvate kinase and glucose-6- phosphatase. Results revealed statistically changes in the metabolites during the sampling, so, glycogen and lactate concentration showed an increasing trend by increasing in fish age, but glucose concentration did not follow this trend. The minimum glucose concentration in brain tissue was observed in seventh stage of sampling. Concentration of metabolism enzymes was showed fluctuations and increasing trend during sampling. Finally, it is proposed that environmental and nutritional factors and different requirement of fish to energy in different stages of life may be effective on metabolites concentrations and metabolism enzymes activity.