STUDY REGARDING THE INFLUENCE OF WATER TEMPERATURE ON HORMONAL STIMULATION OF FEMALES FROM POLYODON SPATHULA BREED FOR MATURATION OF SEXUAL PRODUCTS

C.-A. Barbacariu, I.B. Pagu, E. Măgdici, M.C. Cioran, B. Păsărin

Abstract
   The aim of the current paper was to establish and to optimize the doses of Nerestin 5A hormonal synthesis mixture utilised for hormonal bio-stimulation of females belonging to Polyodon spathula breed, function of water temperature. The current research were carried out on three females' batches, of same age (13 years) and reared in the same environmental conditions in an aquaculture farm from Iaşi County. From all females from reproduction batch were gathered roes using biopsy method and was calculated polarization coefficient of their nucleolus. In this way were chosen 3 individuals from each batch, all of them having polarization coefficient between 0.05-0.07. Experiment started when water temperature reached the value of 13°C, when were injected the females from first batch, after that at 15°C second batch and at 17°C for the third one. Injecting was realised in two rounds: first 20% from dose and second, after 12 hours, 80%. The utilised doses were of 0.12, 0.2 and 0.3 ml/kg female body. Maturation percent was of 100% at all those three females' batches differing, function of water temperature, time for maturation. So, at the same administrated dose with the increasing of water temperature is observed a decreasing of maturation time. Roes' quantity which was gathered was between 73-79 g/kg female body.

Key words: Polyodon spathula, artificial reproduction, Nerestin 5A, sturgeons