Low concentrations of para-aminobenzoic acid increase the viability of fish in early stages of ontogenesis under different environmental conditions

Abstract

The purpose of this work is to summarize the results of multi-year studies (1995–2017) on the effects of PABA on different fish species—peled Coregonus peled (Pallas), broad whitefish Coregonus nasus (Pallas) and common carp Cyprinus carpio L.—in early stages of ontogenesis. The conducted studies revealed the influence of PABA on viability in the early ontogenesis stages of two species of fish in the genus Coregonus with different levels of chromosomal mutability, assessed the ability of PABA to improve the survival of common carp cultivated in contrasting environmental conditions, and researched the ability of PABA to reduce the frequency of spontaneous chromosomal abnormalities in peled, broad whitefish and common carp during the embryogenesis period. The studies were conducted in laboratory and industrial conditions in the north and south of the Tyumen region. After the treatment of peled and broad whitefish roe with PABA, a significant increase (in comparison with the control) in the breaking stage of prelarvae from fertilized eggs laid for incubation was observed. The range of effective dosages of PABA for broad whitefish was wider (from 0.005% to 0.00001%) than for peled (from 0.001% to 0.00001%). The following PABA concentrations were found to be most effective: for peled, 0.001% (the increase in the breaking stage of prelarvae was 1.39 times greater than that of the control) and for broad whitefish, 0.0005% (the increase in the breaking stage of prelarvae was 1.04 times greater than that of the control). Laboratory and industrial studies performed on common carp under the conditions of the Surgut warm-water farm (the north of the Tyumen region) and the Tyumen fish hatchery (the south of the Tyumen region) showed that the greatest effect of PABA in increasing the survival rates of embryos and prelarvae is indicated in low-quality eggs. During incubation of low-quality eggs using para-aminobenzoic acid (0.0008%), the number of developing common carp embryos was 1.5 times higher than the control, and the number of prelarvae was 1.8 times higher than the control. Industrial tests showed that the positive effect of using PABA persists regardless of the conditions used for fish cultivation. Under the conditions of the fish reproduction process in a warm-water farm, the use of PABA significantly increased the survival of common carp embryos. In summary, these studies showed the ability of small doses of PABA to reduce the frequency of chromosomal abnormalities for three types of fish—peled, broad whitefish and common carp—at the gastrula stage.