Cryopreservation of Atlantic salmon Salmo salar sperm: effects on sperm physiology

• Published in: Journal of Fish Biology
• Main Authors: Figueroa, E., Valdebenito, I., Merino, O., Ubilla, A., Risopatrón, J., Farias, J. G.
• Other Authors: Fondo Nacional de Desarrollo Científico y Tecnológico
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2016
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/jfb.13052; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjfb.13052; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jfb.13052

The objective of this study was to determine the effect of freezing on the function in Atlantic salmon Salmo salar spermatozoa. The semen was frozen in Cortland's medium + 1. 3M dimethyl sulphoxide + 0. 3M glucose + 2% bovine serum albumin (final concentration) in a ratio of 1:3 (semen:cryoprotectant) as the treatment (T) and fresh semen as the control (F). Straws of 0·5 ml of sperm suspension were frozen in 4 cm of N 2 L . They were thawed in a thermoregulated bath (40° C). After thawing, the percentage of spermatozoa with fragmented DNA [transferase dUTP (deoxyuridine triphosphate) nick‐end labelling ( TUNEL )], plasma membrane integrity ( SYBR ‐14/ PI ) and mitochondrial membrane potential (ΔΨ MMit , JC ‐1) were evaluated by flow cytometry and motility was evaluated by optical microscope under stroboscopic light. The fertilization rates of the control and treatment semen were tested at a sperm density of 1·5 × 10 7 spermatozoa oocyte −1 , by observation of the first cleavages after 16 h incubation at 10° C. In the cryopreserved semen (T), the mean ± s.d . DNA fragmentation was 4·8 ± 2·5%; plasma membrane integrity 75·2 ± 6·3%; mitochondrial membrane potential 51·7 ± 3·6%; motility 58·5 ± 5·3%; curved line velocity ( V CL ) 61·2 ± 17·4 µm s −1 average‐path velocity ( V AP ) 50·1 ± 17·3 µm s −1 straight‐line velocity ( V SL ) 59·1 ± 18·4 µm s −1 fertilization rate 81·6 ± 1·9%. There were significant differences in the plasma membrane integrity, mitochondrial membrane potential, motility, fertilization rate, V CL , V AP and V SL compared with the controls ( P < 0·05). Also the mitochondrial membrane potential correlated with motility, fertilization rate, V CL and V SL ( r = 0·75; r = 0·59; r = 0·77 and r = 0·79, respectively; P < 0·05); and the fertilization rate correlated with V CL and V SL ( r = 0·59 and r = 0·55, respectively).