The Effect Of Some Relaxants On Anaethesia Of The Winged Pearl Oyster, Pteria Penguin (r Ding)

Mortality, lower pearl retention and low pearl quality can be major problems in cultured pearl production. Cultured round pearls are produced by grafting a round nucleus and a piece of mantle tissue or'saibo', from a sacrificed donor oyster, into the gonad of a recipient pearl oyster. Anaesthetics as a means of reducing stress ,may have a role in the pearl seeding process and this investigation was conducted to identify suitable anaesthetics/chemicals to facilitate the safe, effective anesthetized.six potential anaesthetic treatments: menthol ,2-phenoxyethanol,benzocaine,clove oil, magnesium chloride, low temperature were assessed for their ability to relax the pteria penguin(roding).Reagents were slowly added to groups of 10 oysters placed in ten litre plastic containers filled with filtered sea water,and giving enough time to see reactions. Of these, the following appeared promising(25℃): 2-phenoxyethanol at 1.0,2.0 and 3.0mlL-1,menthol crystal at 0.5 and 1.0 gL-1, clove oil at 1.5 mlL-1 ,2.0 mlL-1,and benzocaine at 500,800, 1000 mgL-1.Of the 10 oysters exposed to each treatment, the highest proportion of relaxed oysters (100%) and the shortest exposure times required for anaesthesia (6.6±1.64 ,4.6±0.99 min), were recorded for the treatments of 3mLL?l.2-phenoxyethanol, 1000 mg L?lof benzocaine. low temperature made pearl oysters strongly close their valves,none of the oysters exposed into magnesium chloride, became relaxed and 1.5 mL L?1clove oil stimulate secretion of mucus and then implantation may becomes difficult.2-phenoxyethanol,benzocaine was selected to determine the effect of changes in relaxant concentration, water temperature and shell size on the time to relaxation and to recovery and on survival after 7 days, Significant responses were found in both chemicals: As anesthetic concentration increased, the time to relaxation decreased while the time to recovery tended to increase. Increased duration of exposure to the relaxants increased the time to recovery. Increases in temperature decreased both the time to relaxation and the time to recovery especially in the 23-25°C range. No association was found with oyster size. No mortalities occurred within 7 days.The toxicity effect of two anesthetic was assessed: pteria penguin was anesthetized for 15,30,45,60min in concentration of 1000 mgL-1 benzocaine and 3.0mlL-1 2-phenoxyethanol,long time and high concentration anaesthetize show benzocaine is the more safely anesthetic for pteria penguin.pteria penguin was exposed to 2.0 mlL-1 2-phenoxyethanol ,and 500,1000 mgL-1 benzocaine ,Once relaxed, oysters were observed every 5 min to evaluate the condition of the tissues.. Mean times for pteria penguin duration as suitable saibo donors was record, The best results were obtained with 500mg L-1 of benzocaine.