Hatchery-scale trials using cryopreserved spermatozoa of black-lip pearl oyster,Pinctada margaritifera

Abstract

-Cryopreservation is a valuable tool for genetic improvement programs. Several bivalve mollusc species have already been the subject of such programs and the Tahitian black pearl oyster industry is now planning the development of selective breeding for desirable traits in Pinctada margaritifera. The ability to cryopreserve spermatozoa would, therefore, offer significant benefits to the cultured black pearl industry. Spermatozoa were cryopreserved with cryoprotectant agent (CPA) 0.7 M trehalose in 0.8 M Me 2 SO and a two-step freezing process was used: straws were first maintained in nitrogen vapour for 10 minutes, then directly plunged into liquid nitrogen and stored for one week before use. The viability of thawed sperm was 23% lower than that of fresh sperm. When using thawed sperm, therefore, a higher sperm/egg ratio of 100 000:1 was required to reach 80% oocyte fertilization, compared with 100:1 for fresh sperm. Nevertheless, this first demonstration of cryopreserved sperm fertility in black pearl oyster confirms the hatchery applicability of the cryopreservation technique defined here. Monitoring for larval viability during the first 23 days of life revealed no significant differences between the progeny produced with cryopreserved sperm and that produced using fresh sperm.

Family effect on cultured pearl quality in black-lipped pearl oysterPinctada margaritiferaand insights for genetic improvement

“…pdf oysters. Spawning was triggered by thermal shock (Hui et al 2011): the pearl oysters were placed in cooled seawater at 20…”

Shell Growth Performance of Hatchery Produced Pinctada margaritifera: Family Effect and Relation with Cultured Pearl Weight

“…Data from shell growth were modelled according to the nonlinear regression of Von Bertalanffy [29], which has been widely used for bivalve growth [25], using XLStat 2008.6.08 software. The Von Bertalanffy equation is:…”

“…Spawning was triggered by thermal shock [25] whereby the pearl oysters were placed in cooled seawater at 20°C for one night before being plunged into seawater at 31°C to 32°C. Immediately spawning started, the male and female oysters were placed in separate containers for gamete collection.…”

“…This bivalve grows rapidly up to a phase of its development where size increase levels off and then falls to zero. On the basis of growth modelling (Von Bertalanffy model [25]), the time required for a pearl oyster to reach the size necessary to be grafted as a recipient (height=100 and juvenile rearing procedures used were as described in [26]. After 3 months, the young spat was placed in plastic trays (Aquapurse ® ) and reared in Vairao lagoon, where they were suspended on long lines.…”

Physiological responses of female and male black-lip pearl oysters(Pinctada margaritifera)to different temperatures and concentrations of food

“…Approximately 7000 persons work on 800 farms (10 000 ha), producing ∼10 t per year, worth e88 million in 2007 (Cochennec-Laureau et al 2010). Almost all cultured pearl oysters are initially collected from the wild, but production of spat in hatcheries is intended to supply oysters with desirable traits, such as pearl colour and fast growth (Le Moullac et al 2003;Hui et al 2011).…”