Effect of low concentrations of para-aminobenzoic acid on viability of broad whitefish Coregonus nasus (Pallas, 1776) at early stages of ontogeny

Abstract

The research aims to study the capability of para-aminobenzoic acid (PABA) to impact the resiliency of 
 a valuable species of cisco fishes – broad whitefish (Coregonus nasus (Pallas, 1776)) – at the early stages of devel-opment. Immediately upon fertilization the fish roe was treated with PABA solutions in low concentrations of 0,01; 0,005; 0,001; 0,0005; 0,0001; 0,00005; 0,00001% during 2 and 4 hours. The control group was not treated with PABA. The study revealed an increase in sack fry output in all experimental variations. The best indications were registered in variations with 0.00005% PABA solution that produced the sac fry output 23.3% higher than an indication in the control group. The subsequent breeding of alevins during 34 days period also confirmed the positive impact of PABA. The treatment of fertilized roe with PABA solution in concentration of 0.00005% increases the alevin survivability by 5.9%, the alevin average weight increases by 5.1 mg. in comparison with the control group. The best results in fry breeding were acquired in the experimental variation with 0.0001% PABA solution: the alevin survivability was by 15.6% higher than in the control group; an average weight of tested alevins exceeded an average weight of alevins in the control group by 8.6 mg. Cytogenetic analysis showed that the treatment of roe with PABA decreases the rates of chromosomal distortions of broad whitefish by 1.5-2 times in comparison with the control group on the gastrula stage. These results demonstrate the ability of PABA to increase both the survivability and the growth speed of broad whitefish on its early stages of ontogenesis, which can be used in raising the efficiency of industrial fish reproduction.