Reproduccion animañ

Research Article

Turk. J. Vet. Anim. Sci. 2009; 33(3): © TÜBİTAK doi:10.3906/vet-0712-19

Effects of addition of vitamin B12 to the extender on post-thaw motility, acrosome morphology, and plasma membrane integrity in bull semen

Jian-Hong HU1, Qing-Wang LI1,2, Yu-Lin CHEN1,∗, Zhong-Liang JIANG1, Yong-hong JIA3, Li-qiang WANG1, Bo-Bo OU1
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College of Animal Science and Technology,Northwest A & F University, Yangling, Shaanxi 712100, CHINA Qinhuangdao, Hebei 066004, CHINA
3Domestic Animal Improving Station, Jingyang, Shaanxi 713702, CHINA

2Department of Biological Engineering, College of Environment and Chemistry Engineering, Yanshan University,

Received: 17.12.2007

Abstract: To investigate the effects of supplementation of vitamin B12 on bovine sperm post-thawquality, vitamin B12 was added at the concentrations of 1.25, 2.50, 3.75, and 5.00 mg/mL to bovine semen cryoprotective medium. The results indicated that the motility and VSL, VCL, STR, and VAP values of sperm supplemented with 2.50 mg/mL vitamin B12 were significantly higher than those of other concentrations (P < 0.05). No significant difference was observed for LIN and ALH values and thepercentage of grade a spermatozoa between the extenders containing 2.50 mg/mL and 3.75 mg/mL vitamin B12 (P > 0.05). The percentages of acrosome-intact and plasma membrane- intact spermatozoa were significantly improved (P < 0.05) by supplementing with 2.50 mg/mL vitamin B12. With all parameters measured, the concentration of 2.50 mg/mL vitamin B12 showed the best results on the quality of bovine semenin freezing-thawing. In conclusion, the addition of 2.50 mg/mL vitamin B12 to the extender improved the bovine frozen semen quality. Key words: Bovine semen, vitamin B12, cryopreservation, sperm motility, CASA

Introduction Vitamin B12 is one of the water-soluble vitamins functioning as a coenzyme in a number of biochemical reactions, such as methionine synthesis and the metabolism of branchedamino acids (1). Because of its stability, cyanocobalamin is the form typically used in vitamin supplements. As for reproductive performance, it was demonstrated that
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spermatogenesis would be improved in humans when a large amount of vitamin B12 was given to patients with oligospermia (2,3). In animal experiments, it was also shown that vitamin B12 deficiencyinduced atrophic changes and the arrest of spermatogenesis in rats. Watanabe et al. (4) examined the effects of dietary vitamin B12 deficiency on sperm maturation in developing fetuses and growing newborns in rats.

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Effects of addition of vitamin B12 to the extender on post-thaw motility, acrosome morphology, and plasma membrane integrity in bull semen

Vitamin B12 deficiency increasedthe incidence of abnormal sperm and decreased the motility and velocity of the sperm in male rats, suggesting that dietary vitamin B12 deficiency during gestation might induce irreversible damage in the germ cells of embryos and affect the maturation of spermatozoa. Vitamin is essential for DNA, transfer RNA, and protein synthesis. Because DNA synthesis was a main part of spermatogenesis (5-7),vitamin B12 was probably important to this process. Recently, some reports have shown a positive effect of vitamin B12 supplementation on spermatozoa motility and spermatozoa count. Ha and Zhao (8) indicated that vitamin B complex could improve postthaw motility and protect the integrity of ram spermatozoa membrane during the freezing-thawing. Cai et al. (9) studied the effects of vitamin B12 onconfiguration of bull’s frozen-thawed sperm and indicated that 0.5% (v/v) vitamin B12 supplementation in the extender significantly improved the sperm quality. There has been little published work in recent years on the effects of supplemental vitamin B12 in the extender on frozen semen quality in bovine. Despite the intrinsic roles of vitamin B12 supplementation in sperm cryopreservation, the...