Effectiveness of African catfish pituitary extracts, dagin and water flow for optimising egg production, fertilisation and hatchability in artificial spawning of Barbus altianalis

Abstract

Fish inducing hormones are widely used in commercial aquaculture to facilitate continuous
supply of sufficient seed required on regular basis by the farmers. The objective of this study
was to optimise production of viable eggs for improved hatchability during artificial spawning
in Barbus altianalis. Two experiments were conducted, namely (i) experiment I evaluated the
efficiency of using catfish pituitary extracts in spawning of second generation broodstocks
compared to that of Dagin and water flow. (ii) experiment II examined ripe running females
facilitated to spawn by running water only. Fish treated with pituitary extracts performed
much better than those treated by Dagin with respect to fertilisation rates at 80.27 ± 39.57%
(U = 66.5, p < 0.001) and working fecundity at 2314.40 ± 882.04 (U = 59.5, p < 0.05). However,
the difference in hatchability was not significant (p > 0.05). In experiment II, hatchability and
working fecundity were significantly higher when fish were striped after 4 hours (100 degree
hours at 25 oC) of running water than those striped after 10 hrs (250 degree hours) but
fertilization rates were not different. The findings indicate that catfish pituitary extracts are
more effective in inducing B. altianalis to spawn than those treated with Dagin. However, the
observations made on ripe running females in both experiments suggest that they should not
be induced with any hormone. Hence, the cost of spawning could further be reduced using
running water, especially in wet seasons when the majority are ripe