Author(s): Agbebi O. T.

Abstract: Triploidy was induced in Heterobranchus longifilis by injecting the brooders with ovaprim for 15 hours latency period. The fertilized eggs were subjected to chromosome studies, after giving cold shock treatment at 50C for 40 minutes. Diploid and triploid juveniles raised with mean weight of 32.55g and 42.40g respectively were reared in 2 x 2 x 1.2 m3 outdoor concrete tanks. The treatments were in triplicates and were fed with diets containing 45% crude protein. At juvenile stage to nine months of age, triploid H. longifilis growth was significantly different (p<0.05) having (mean weight 980g), significantly heavier than the diploid counterparts (mean weight 788g). Histological examination revealed that both diploid and triploid fish had well-developed genitalia, but no other sexual characteristics could be seen in the triploids. The comparative hematological parameters showed that diploid would respond to stress and injuries more than triploid. Dietary requirements showed that the triploids converted feed efficiently (FCR=1.05) than the diploid (FCR=1.95). Result of weight gain in triploid gave clear evidence that triploids performed better than diploids and this confirmed that triploids are larger than their diploid strains and may provide greater profits in commercial catfish culture than the diploids.

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