**13. Conclusion**

Based on above review, the conclusion can be drawn as follows: (I) some antioxidants, such as, Oryzanol, L-cysteine and its combination with DHA from fish oil, Vitamin E, Vitamin C, can be used in order to improve the quality of frozen boar semen" (II) the artificial

Cryopreservation of Boar Spermatozoa: An Important Role of Antioxidants 159

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Buranaamnuay, K., Tummaruk, P., Singlor, J., Rodriguez-Martinez, H. and Techakumphu,

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Chanapiwat, P., Kaeoket, K. and Tummaruk, P. 2009. Effects of DHA-enriched hen egg yolk

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Curry, M.R. and Watson, P.F. 1994. Osmotic effects on ram and human sperm membranes in

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Eriksson, B.M., Petersson, H. and Rodriguez-Martinez, H. 2002. Field fertility with exported boar semen frozen in the new flatpack container. Theriogenology. 58: 1065-1079. Eriksson, B.M., Vazquez, J.M. and Martinez, E.A. 2001. Effects of holding time during

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**8**

*Japan* 

**Cryopreservation of Rat Sperm** 

*1 Laboratory of Animal Genetics and Reproduction, Faculty of* 

The laboratory rat, *Rattus norvegicus*, was the first mammalian species domesticated for scientific research, which work dating back to before 1850. From this auspicious beginning, the rat has become the most widely studied experimental animal model for biomedical research (Jacob, 1999). Since the development of the first inbred rat strain by King 1909, over 500 inbred rat strains have been developed for a wide range of biochemical and physiological phenotypes and different disease models (Aitman et al., 2008, Canzian. 1997). In the last decade, there has been an extraordinary increase in rat genomic resources (Gibbs et al., 2004, Pennisi. 2004), and the advent of knock-out technology allow the insertion or deletion of individual genes into the rat by advances in stem-cell technology (Geurts et al., 2009, Izsvak et al., 2010, Tong et al., 2010). Thus, a wide array of research opportunities now open up, especially in studies involving the laboratory rat (Hamra. 2010). However, protocol for sperm cryopreservation and oocytes fertilized *in vitro* by using cryopreserved sperm are still under development for preservation of most rat strains. Therefore, greater use of the cryopreservation of rat sperm may provide an essential resource to preserve and increase

In this chapter, we will introduce several of these approaches to cryopreserving the rat sperm. It will be valuable for developing new freezing extender for cryopreservation of rat sperm, and might be applied to other reproductive technologies in this species for

The first live-born rat derived from frozen-thawed sperm were successfully reported artificial insemination (AI) by using frozen-thawed rat sperm, and also reported cryopreservation of several strains of rat sperm, including those from mutant and transgenic rats (Nakatsukasa et al., 2001, Nakatsukasa et al., 2003). More recent publication by same group confirmed that cryopreserved rat sperm can be revitalized and result in the birth of live offspring through embryo transfers after in vitro fertilization (*IVF*) (Seita et al., 2009a). Although the authors mentioned by another publication that intracytoplasmic sperm injection (ICSI) is the only way to routinely obtain offspring routinely derived from oocytes

the number of valuable genetic strains for research and application.

**2. Reporting studies of rat sperm cryopreservation** 

preservation of valuable rat strains.

**1. Introduction** 

 *2 Laboratory of Animal Reproduction, Graduate School* 

Hideaki Yamashiro1 and Eimei Sato2

*of Agricultural Science, Tohoku University* 

*Agriculture, Niigata University* 

