Female Japanese Quail Coturnix Japonica Research Articles

Maternal dietary carotenoids mitigate detrimental effects of maternal GnRH on offspring immune function in Japanese quail Coturnix japonica

Maternal resources deposited in eggs can aff ect the development of several off spring phenotypic traits and result in tradeoff s among them. For example, maternal androgens in eggs may be benefi cial to off spring growth and competitive ability, but detrimental to immunocompetence and oxidative stress. In contrast, maternal antioxidants in eggs may be benefi cial if they mitigate oxidative stress and immunosuppressive eff ects of androgens. We investigated possible interactive eff ects of maternal steroids and carotenoids on aspects of off spring physiology and phenotype, by simultaneously manipulating levels of androgens (via gonadotropin-releasing hormone, GnRH-challenges) and carotenoids (via diet supplementation) in captive female Japanese quail Coturnix japonica during egg laying. Carotenoid supplementation of hens, which elevates yolk concentrations of carotenoid and vitamins A and E, enhanced egg hatching success, off spring survival to age 15 d, and size of the bursa of Fabricius in off spring. In contrast, repeated maternal GnRH challenges, which elevated yolk testosterone concentrations, enhanced off spring neonatal size, but negatively aff ected bursa size. However, interaction among the treatments suggests that the positive eff ect of maternal carotenoid supplementation on plasma bactericidal capacity was mediated by maternal GnRH challenges. Chicks originating from carotenoid-supplemented hens were less immunosuppressed than those originating from carotenoid-supplemented GnRH-challenged hens, which were less immunosuppressed than chicks from GnRH-challenged females not supplemented with carotenoids. Females availability of carotenoid enriched diets allows them to enhance the development of off spring immune system via carotenoids and vitamins deposited in egg yolks and off set detrimental eff ects of androgens deposited by GnRHchallenged females.

Application of modern endocrine methods to conservation biology

Ishii, S. 1999. Application of modem endocrine methods to conservation biology. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban. Ostrich 70 (1): 33–38. I report here on novel endocrinological methods originally developed for the artificial breeding of the Japanese Crested Ibis, Nipponia nippon. According to the most recent information. the only wild population in the world is one of about 60 individuals in Yang Xian, China. Captive populations of 54 and 17 individuals are located in Yang Xian and at Beijing Zoo, respectively and a single female of this species survives in Japan. Females of many birds stop breeding when they are brought to captivity. Hormone administration is considered to be effective in stimulating the breeding activity of such females. If the ovary of a captive female contains well-developed ova but does not ovulate, the problem is not serious. Ovulation can be induced by injection of gonadotropic hormone. However, if the ovary is regressed and contains no developed ova, the problem is serious. Until recently, no avian endocrinologist had been able to induce ovulation in hens with a regressed ovary. We developed a non-invasive method to assess the ovarian and testicular condition of birds by analysing gonadal sex steroid hormones in droppings. By using this method, we can decide whether the ovary contains developed ova or not and whether a male is sexually active or not. To reactivate a regressed ovary, we employed gonadotropin administration by means of the osmotic pump implantation in female Japanese Quail Coturnix japonica kept under short-days and then injected with the gonadotropin preparation once a day for several days. About 50% of the females laid an egg or eggs in response to the injection. Seven of the eggs were artificially incubated and two of them hatched. One of the two was revealed to be a male and fertile. The faecal sex steroid assays have been successfully applied to males of the Japanese Crested Ibis and Kakapo Strigops habroptilus in New Zealand. Although too late to apply the hormone administration method to the Japanese Crested Ibis for breeding, application of the method to the Kakapo is now being examined in New Zealand.