Initiative on Avian Primordial Germ Cell Cryobanking in Thailand.

Background: Biobanking the reproductive tissues or cells of animals preserves the genetic and reproductive ability of the species in long-term storage and promotes sharing of reproductive materials. In avian species, the primordial germ cell (PGC) is one of the most promising reproductive cells to be preserved in biobanks, due to self-renewal properties and direct access to the germ line mediated by PGC transfer. Methods: To conserve the genetic resource of local chicken breeds that are of conservation importance, we systematically isolated two types of pregonadal PGCs from chicken embryos-circulating and tissue PGCs. PGCs of individual embryos were separately isolated, cultured, and cryopreserved. Characteristics of cultured PGCs are described and evaluated. Results: The efficiency of PGC isolation from individual embryos was 98.9% (660/667). In most cases, both matching circulating and tissue PGC lines were isolated from the same embryo (68.2%, 450/660), whereas the remaining lines were from a single source, being either tissue (30.6%, 202/660) or circulating (1.2%, 8/660). Efficient PGC isolation and proliferation can be expected in cultures of circulating PGCs (68.7% and 64.3%, respectively) and tissue PGCs (97.8% and 80.7%, respectively). Following cryopreservation, recovered cells sustained PGC identities including expression of chicken vasa homolog and deleted in azoospermia-like proteins and migration ability to recipient embryonic gonads. Culture conditions equally supported proliferation of circulating and tissue PGCs from both sexes. Combining tissue PGC culture in the regimen prevented 30.3% loss of PGC cultures in the case where circulating PGC culture was ineffective. Cultured circulating and tissue PGCs were similar in morphology, but optimal culture characteristics were different. Conclusion: We applied the approach of PGC isolation from blood and tissue origins on a wide scale and demonstrated its efficiency for biobanking chicken PGCs. The workflow can be operated effectively almost year-round in a tropical climate. It was also described in ample and practical details, which are suitable for adoption or optimization in other conditions.

Assessment of basic seminal characteristics, sperm cryopreservation and heterologous in vitro fertilisation in the fishing cat (Prionailurus viverrinus).

Conservation of the fishing cat, a threatened south-east Asian felid, could benefit from effective ex situ genetic management and breeding programmes, including the use of assisted reproduction. The aims of the present study were to: (1) characterise basal seminal traits of fishing cats in Thailand zoos; and (2) investigate the effect of cryopreservation on sperm motility, acrosomal integrity and in vitro function. Seminal traits were evaluated in electroejaculates collected from eight males. Spermatozoa were diluted in n-tris(hydroxymethyl)-methyl-2-aminoethanesulfonic acid Tris (TEST)-yolk buffer (TYB) without glycerol, then diluted further with TYB with glycerol (4% final concentration) at either 25 degrees C or after slow cooling to 5 degrees C and frozen in straws over liquid nitrogen vapour. After thawing, sperm function was assessed by insemination of viable domestic cat oocytes. Fishing cat ejaculates averaged (+/- s.e.m.) 43.6 +/- 14.2 x 10(6) motile spermatozoa with 33.5 +/- 6.8% normal sperm morphology. Semen processing had a negligible effect (P > 0.05) on sperm motility and acrosomal integrity, but values were reduced (P < 0.05) after thawing. All thawed samples fertilised domestic cat oocytes, with 62.1% (36/58) of mature oocytes cleaving. Glycerol addition at 5 degrees C resulted in higher (P < 0.05) post-thaw motility and intact acrosomes than glycerol addition at 25 degrees C. In conclusion, good-quality ejaculates can be obtained from Thai fishing cats and their spermatozoa exhibit adequate function after cryopreservation for in vitro fertilisation procedures.

Seroprevalence of Toxoplasma gondii in captive felids in Thailand.

The prevalence of antibodies against Toxoplasma gondii was investigated by commercial latex agglutination test kit (Toxocheck-MT 'Eiken') in captive felids maintained at zoos and a wildlife breeding center in different geographic regions of Thailand. Sera from a total of 136 captive felids of 12 species was obtained between 2002 and 2004. The overall seroprevalence of T. gondii was found in 21 of 136 (15.4%) felids. The titers varied from 1:64 (eight samples) to 1:8192 (one sample). The seroprevalence in different geographic regions were from 0% in the northern area to 23% in the southern area. This study suggested a widespread exposure of captive felids to T. gondii in Thailand and this is the first report of serologic analysis for T. gondii in captive felids in Southeast Asia.