Effect of various levels of dissolved oxygen on reactive oxygen species and cryocapacitation‐like changes in bull sperm |
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Authors: | Beigh Y Amin Jai K Prasad Subrata K Ghosh Shabir A Lone Abhishek Kumar Abdul R Mustapha Omer Din Ajay Kumar |
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Institution: | 1. Division of Animal Reproduction, ICAR‐Indian Veterinary Research Institute, Izatnagar, India;2. Artificial Breeding Research Center (ABRC), Animal Reproduction, Gynecology and Obstetrics, ICAR‐National Dairy Research Institute, Karnal, India;3. Department of Theriogenology, Faculty of Veterinary Medicine, University of Maiduguri, Borno State, Nigeria;4. Biochemistry Division, ICAR‐Indian Veterinary Research Institute, Izatnagar, India |
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Abstract: | The present investigation was carried out to study the effect of various levels of dissolved oxygen (DO) on reactive oxygen species (ROS) and cryocapacitation‐like changes in bull sperm. Egg yolk–Tris–glycerol (EYTG) extender was split into four subextenders; viz., Extender I (control; no flushing with liquid nitrogen (LN2)), Extender II, Extender III and Extender IV were flushed with LN2 for 40, 16 and 8 min, respectively. The DO levels were standardized to 11.7, 2, 4 and 8 ppm, respectively, in control (Extender I), Extender II, Extender III and Extender IV. Ejaculates with mass motility of ≥ 3+ were divided into group I (diluted with Extender I), group II (diluted with Extender II), group III (diluted with Extender III) and group IV (diluted with Extender IV) up to 80 × 106 sperm/ml. Extended semen samples were packed in French mini straws (0.25 ml), equilibrated and cryopreserved. Semen samples were evaluated at prefreeze and post‐thaw stage for various parameters (DO, progressive motility (PM), viability (VIB), acrosomal integrity (AI), hypo‐osmotic swelling (HOS) test, ROS, cholesterol (C) and phospholipid (P). The percentage of PM, VIB, AI, HOS test, cholesterol (C) and phospholipid (P) levels, and capacitated sperm were significantly (p < 0.05) higher in groups III and IV as compared to groups I and II. However, the acrosome‐reacted sperm (%; pattern AR) were significantly (p < 0.05) decreased in group III as compared to all other groups. Besides the proportion of sperm displaying tyrosine‐phosphorylated pattern, EA (fluorescence at both equatorial and anterior acrosomal regions, i.e. high capacitation level) was significantly (p < 0.05) reduced in group III compared to all other groups. In conclusion, varying DO levels in the extender significantly affect sperm quality, ROS production and capacitation‐like changes in bulls. |
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Keywords: | cryocapacitation dissolved oxygen LN2 reactive oxygen species sperm |
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