Performance of triploid edible oyster Crassostrea madrasensis (Preston): gonad development and biochemical composition

Abstract

One of the most important parameters for successful commercial exploitation of bivalves is a need for fast growth. The potential for increased growth, meat yield and quality are the main advantages of triploid oysters. Triploid organisms have a limited capacity to develop gonads and thus are considered sterile or partially sterile and are useful and advantageous in shellfish aquaculture. Oysters occur all along the Indian coasts in backwaters, bays and estuaries. The edible oyster Crassostrea madrasensis is a commercially important bivalve distributed all along the east and west coasts of India and the edible oyster farming is becoming increasingly popular. C. madrasensis is a suitable species for culture because of faster growth rate and tolerance to wide range of salinity. The present study compares triploid and diploid edible oysters (C. madrasensis) of the same age, grown under similar conditions for one year to determine the accumulation of biochemical reserves at first maturation. Triploid edible oysters were produced by treating newly fertilized eggs with 6-Dimethyl amino purine (6-DMAP). Stunted growth of gonads was seen in triploids while in diploids both ovaries and testis were functional. Higher levels of total carbohydrate (including glycogen 20.25% in meiotic I triploids and 18.78% in meiotic II triploids over 12.95% in diploids) has a major role in increasing the superior performance of triploids. Meat quality is also expected to be higher in triploids.