title: Development and function of pearl-sacs grown from regenerated mantle graft tissue in the black-lip pearl oyster, Pinctada margaritifera (Linnaeus, 1758).
abstract: Current pearl grafting techniques were developed in the early 1900s and have changed little since. They involve the sacrifice of donor pearl oysters to provide graft tissue (saibo) that is implanted into host oysters. This study assessed the feasibility of using regenerated graft tissue for pearl production in the 'black-lip' pearl oyster, Pinctada margaritifera. Twelve days after grafting with regenerated graft tissue, there was complete encapsulation of the nucleus by the fully developed pearl-sac and the first layer of organic matrix had been secreted. Sixteen days after grafting, the pearl-sac was completely integrated with host tissue. The epithelial cells in the pearl-sac continued to secrete the organic matrix layer but there were no signs of nacre deposition at this stage. However, after three months of culture, nuclei in oysters grafted with regenerated mantle tissue were completely covered with nacre. The average nacre thickness on pearls produced from regenerated (0.547 ± 0.01 mm, n = 8) and normal (0.532 ± 0.01 mm, n = 8) mantle tissue did not differ significantly (p > 0.05). Nacre secretion rates, over the 80 day period subsequent to pearl-sac formation were 6.84 ± 0.1 μm day(-1) and 6.66 ± 0.1 μm day(-1) for oysters grafted with regenerated and normal mantle tissue, respectively. These means were not significantly different (p = 0.258). Our results clearly show that regenerated mantle tissue can function successfully as saibo for pearl production in P. margaritifera. This finding could provide significant benefits to pearl farmers and a basis for further development of current pearl grafting practices.
authors.affiliation: Pearl Oyster Research Group and Centre for Sustainable Tropical Fisheries and Aquaculture, College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia. Electronic address: pranesh.kishore@my.jcu.edu.au.
authors.forename: Pranesh
authors.initials: P
authors.lastname: Kishore
authors.affiliation: Pearl Oyster Research Group and Centre for Sustainable Tropical Fisheries and Aquaculture, College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Southgate
mesh_terms: D000825:Animal Structures / Q000637:transplantation*; D000818:Animals; D060734:Nacre / Q000378:metabolism; D049911:Pinctada; D019737:Transplants
chemical_list: D060734:Nacre
keywords: Anaesthetics; Grafting; Nacre secretion; Pearl oyster; Pearl quality; Pearl-sac; Pinctada margaritifera; Regenerated mantle tissue