Mathematical modeling of the heat transfer phenomena during the cryopreservation of rainbow trout (Oncorhynchus mykiss) sperm from Northern Patagonia

VICTORIA SANTOS; CRICHIGNO, SONIA A.; VICTOR E. CUSSAC; N. ZARITZKY

Buenos Aires

Congreso; 11° Congreso Mundial de Ingeniería Química a realizarse en Buenos Aires; 2023

entro de Convenciones de la UCA-BsAs, World chemical engineering counsil, Asociación argentina de ingenieros químicos

ABSTRACTThe cryopreservation of rainbow-trout sperm under field conditions is carried out under a wide variability of conditions and a lack of standardization of the freezing protocol is observed. The objective of this work is to assess the cryopreservation protocols by developing a numerical model to simulate the freezing process of rainbow trout semen in plastic straws using temperature dependent thermophysical properties. Thermophysical properties of the semen suspension as a function of temperature were determined considering the water-ice change of phase. The finite element method was used to solve the non-stationary heat transfer equation; the model was applied to study the effect of the thermophysical properties of different plastic straw materials (polyethylene-terephthalate glycol, polyvinyl-chloride, and polypropylene) on freezing rates. Cooling rates were experimentally determined in 0.5 mL straws containing rainbow trout sperm submitted to different external temperatures by varying the height above the level of liquid nitrogen, and fertilization trials were performed. Results showed that the freezing rate depended on the external nitrogen vapor temperature to which the straws were exposed; an improvement on fertilization trials was achieved when the average external nitrogen temperature was -124.1 ºC during 1.2 min. These conditions corresponded to straws immersed nitrogen vapors at a height of 2 cm above the level of liquid nitrogen in the Styrofoam-box.