Semen characteristics and biochemical composition of cloacal foam of male Japanese quails (Coturnix coturnix Japonica) fed diet incorporated with selenium
Selenium (Se) is recognized as having anticarcinogenic and antiviral properties, and it has an important role in the functioning of the reproductive system. The importance of Se in animal nutrition lies on the two lines of antioxidant defence in the cell relies on the activity of GSH‐Px fact. Detoxification of hydrogen peroxide formed by SOD is the first, and detoxification of hydroperoxides is the sd line of antioxidant defence, which in turn depends on adequate selenium status in the cell (Surai, 2002). Among the feed derived natural antioxidants, Se has an exceptional place for regulation of numerous functional processes in the body. Adequate Se supplementation is considered to be a crucial factor in maintaining the high productive and reproductive characteristics of commercial poultry (Surai, 2002). Higher doses of Se such as 200 ppb and 300 ppb positively influenced the laying performance of the hens, but Se at a lower dose, that is 100 ppb, has not any positive effects (Bonomi, 2001). Se is very much essential for production performance, normal hatchability and egg production in avian species (Austin and Milton, 1974). There are two forms of Se which used in poultry diet, that is, inorganic and organic (in the present study organic Se is used). The US Food and Drug Administration (USFDA) approved the use of organic Se as a feed supplement for all species of poultry (Federal Register 2002). Se is an essential element for spermatogenesis, and it can protect the biological membranes from lipid peroxidation during spermatogenesis. Ebeid (2009) reported that Se can reduce the peroxidation of seminal lipids and enhance the glutathione peroxidase (GPx) activity leading to maintain adequate viability of sperms to complete the fertilization process. Se can accumulate in high concentrations in endocrine glands in many livestock species. Se was permitted as a feed supplement since 1974, and it has been clearly demonstrated that this trace element is essential for male fertility (Hansen and Deguchi, 1996). Dietary deficiency of selenium decreased the numbers of normal spermatozoa, motility and fertilizing ability in poultry and rodents (Surai, 2000; Surai et al., 2001).
The male Japanese quail (Coturnix coturnix japonica) has a unique reproductive system among the avian species which belongs to androgen dependent cloacal gland (Klemm et al., 1975). This gland is functionally developed only in sexually active male quail, but both sexes of quail have the gland (Fuji and Tamura, 1967). This gland has high degree of correlation between gland size and testes weight (Follett and Maung, 1978; Biswas et al., 2007a,b). Measurement (length and width) of cloacal gland provides a valuable non‐invasive method of predicting testicular activity and fertilizing ability of male quail (Mohan et al., 2002), whereas the appearance of foam in the gland indicates the sexual maturity in young birds (Siopes and Wilson, 1975). The cloacal gland secretes meringue‐like foam constantly during copulation and defecation time (Fujihara, 1992). Only limited information is available in the literature on relationship of cloacal gland with testicular weight, fertility and testosterone level in Japanese quail (Siopes and Wilson, 1975; Follett and Maung, 1978). To strengthen the available knowledge, this work was carried out to know the effect of Se on biochemical characteristics of foam in Japanese quail. During the last four decades, many researcher have been reported the conflicting reports for the role of cloacal foamy material on reproductive performance in Japanese quail (Ayyagari, 1982), few of them reported that quail foam substances might have a beneficial effect on the fertilizing ability of spermatozoa (Mohan et al., 2004; Biswas et al., 2007a,b, 2010), while others reported that foam might be detrimental to quail spermatozoa (Ayyagari, 1982).