Blackwell Publishing Journal Backfiles 1879-2005
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Abstract. Triploidy was induced in three full-sib families of sea bream, Pagrus major (Temminck & Schlegel), by subjecting the fertilized eggs to cold-shock treatment at 0°C for a 12 min duration, starting 3 min after insemination. Results showed that this treatment gave 100% triploid fish with reasonable survival rates of more than 61% up to first feeding, Triploidy induction was proved by the use of allozyme markers at three (ADH*, EST* and 6PGD*) loci and red blood cell size analysis.At 2 months of age, the survival of the triploid group was lower than that of the diploids but it was comparable at 10 months. No differences in growth rate between diploid and triploid full-sibs were observed up to the age of 10 months. However, differences in body weight between families were noticed both in diploid and triploid groups when cultured in the same net cage. This possibly suggests a high heritability for the trait examined in the broodstock. The gonads of the triploid fish were significantly smaller than those of the diploids, Histological analysis of the gonads revealed sterility in triploid fish.
Type of Medium: