Growth and survival of diploid and triploid bata, Labeo bata (Hamilton, 1822)

Abstract

Abstract Bata (Labeo bata), an indigenous, freshwater minor carp, is a great delicacy in Bangladesh. In its natural fishery, bata contributes significantly to the health and nutritional security of a large section of the fisher communities in Bangladesh. However, it is not a popular farmed fish because of its small size and slow growth rate. The induction of triploidy, aimed at providing faster growth and larger body size, could be appropriate for L. bata to enhance its aquaculture potential. In the present study, we induced triploidy in L. bata by applying heat shock on fertilised eggs (that were maintained at the ambient temperature of 26–28°C), 3 to 5 min post fertilisation and for durations ranging from 1 to 2 min. Four different temperatures, namely, 38, 39, 40 and 41°C, were tested as heat shock treatments. The optimum treatment combination for triploidy induction in L. bata was found to be 39°C for the 1 min duration, 3 min after fertilisation, yielding 100% triploidy. Karyotyping revealed 72 chromosomes in the triploid fish (3n), whereas the diploid control (2n) had 48 chromosomes. The growth performance of the triploid hatchlings was compared against the diploid control in experimental ponds. After 12 weeks of rearing, the triploid fish were significantly heavier (p < 0.05) than their diploid counterparts. The survival rate of the triploids was also better (69%) than that of diploids (56%). Overall, results revealed better performance (growth and survival) of triploid bata over diploids, indicating that the farming of triploid bata can be a viable practice in Bangladesh.

Keywords

• chromosome manipulation
• heat shock treatment
• small indigenous fish
• triploidy