ISHII, Susumu; Waseda Univ., Tokyo: Endocrinological approaches to conservation biology using classic and modern techniques

For captive and artificial breeding of the Japanese crested ibis or Toki, Nipponia nippon, we developed the following methods: non-invasive estimation of gonadal endocrine activity using fecal sex steroid analysis, hormonal treatments to induce ovarian development, ovulation and oviposition in the Japanese quail as a model bird and non-invasive sex identification of newly hatched chick of the ibis. A combination of clonic and acute administrations of crude chicken gonadotropin to female Japanese quail with completely regressed ovary could induce full process of the ovarian growth, ovulation and oviposition. Two of the oviposited eggs were incubated and two normal chicks hatched. One of them was a fertile male. However, chicken gonadotropin had minimal effect on the ovary of a related ibis species. We also conducted the genomic cloning of the follicle-stimulating hormone (FSH) beta subunit molecule gene and the common alpha subunit gene of the ibis. This information is indispensable to produce recombinant ibis hormone that is useful for artificial reproduction of the ibis. We found partial difference in the structure of the FSH beta gene and also the structure of mitochondrial DNA between Chinese individuals and Japanese individuals of the ibis. Relation of the Japanese and Chinese populations of the ibis will be discussed basing on these differences. In addition, when the last Japanese male of this ibis species died, we conducted isolation of living cells from the male preserved the living cells in liquid nitrogen for future use. The preserved cells may be used for artificial re-production of the Japanese bird using nuclear implantation technique to primordial germ cells. At the same time, tissues of almost all the organs of the bird was preserved in a frozen condition in liquid nitrogen. We are planning to provide the preserved material to qualified biologists for scientific study on Nipponia nippon.