Triploidia De Peces

Reviews in Fish Biology and Fisheries (2004) 14: 391–402 DOI 10.1007/s11160-004-8361-8

Ó Springer 2005

The biology of triploid fish
Basant K. Tiwary1, R. Kirubagaran2 & Arun K. Ray3
Department of Life Science, Assam (Central) University, Silchar 788 011, India (Phone: +91-3842-270823; fax: +91-3842-270802; E-mail: basant68@email.com; 2National Institute of Ocean Technology, Chennai 601302, India; 3Department of Animal Physiology, Bose Institute, Kolkata 700 054, India
Accepted 8 December 2004
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Contents
Abstract Introduction Induction of triploidy Detection of triploids Morpho-anatomical changes in triploids Growth performances in triploids Haematology of triploids Food conversion efficiency in triploids Behavior of triploids Endocrinology of triploids Gonadal development intriploids Future prospects in triploid research Conclusion References page 391 391 392 392 393 393 394 394 395 395 396 397 398 398

Key words: detection, growth, induction, morpho-anatomy, physiology, triploidy Abstract This review deals with major areas of triploidy research in fish. It includes not only methods for induction and detection of triploidy but also the impact of triploidy onmorphology, anatomy, growth, haematology, energetics, behaviour, endocrinology and gonads in various species of fish, studied so far. The future prospects of research on triploid fish are discussed inviting researchers with diverse areas of interest in fish biology.

Introduction Induction of triploidy in fish has been found to be useful for the control of overpopulation, for increasing growth in juveniles,and for extending survival and improving growth in mature fish. Triploids have three sets of chromosomes instead of two sets in diploids. Triploids are generally sterile due to irregular meiotic division of chromosomes resulting in reduced gonadal development and aneuploid gametes. Therefore, in such fish, the energy consumption for sexual maturation may be avoided and more biological effort

maybe directed towards improving flesh quality and somatic growth. Induction of triploidy has been achieved in many species of fish by treatment designed to block the second meiotic division or to prevent extrusion of the second polar body of the egg. Retention of second polar body of the fertilized egg may happen without special treatment in some cases or may result from temperature, pressure orchemical treatment of the fertilized egg. The natural occurrence of triploids in fish populations is due to occasional failure of extrusion of the second polar body of the fertilized egg (Thorgaard and Gall, 1979).

392 Induction of triploidy Temperature treatments (both heat and cold shock) of fertilized eggs have widely been used to suppress second polar body extrusion for induction of triploidy infish. Temperature shock treatments are inexpensive to apply and can be successfully adapted for mass production by fish farms. Cold shock in general has been most successful in warm water fishes (Thorgaard and Gall, 1979). However, heat shock was 100% effective in tilapia (Oreochromis mossambicus) (Varadaraj and Pandian, 1988). Hydrostatic pressure shock has also been successfully used to blocksecond polar body extrusion in rainbow trout (Onchorhynchus mykiss) (Lou and Purdom, 1984), zebrafish (Danio rerio) (Streisinger et al., 1981), common carp (Cyprinus carpio) (Linhart et al., 1991), Nile tilapia (Oreochromis niloticus) (Hussain et al., 1991), yellow perch (Perca flavescens) (Malison et al., 1993), coho salmon (Oncorhynchus kisutch) (Piferrer et al., 1994a), and hybrid channel catfish(Ictalurus punctatus) · blue catfish (Ictalurus furcatus) (Goudie et al., 1995). Chemicals were also used to block polar body extrusion in fertilized eggs of fish. Refstie et al. (1977) produced mosaic polyploid–diploid Atlantic salmon (Salmo salar) after exposing fertilized eggs to cytochalasin B. Smith and Lemoine (1979) reported similar production in brook trout (Salvelinus fontinalis) after...