BIOCHEMICAL AND MORPHOMETRIC PARAMETERS OF PRE-LARVAE OF THREE SALMONIDS SPECIES AT ONE-DAY AGE

Purpose. To study and analyze the morphometric and some biochemical parameters of pre-larval brown trout, rainbow trout and brook trout in post-embryonic period under the conditions of "Rybnyi Potik” farm in the Transcarpathian region for further use of the obtained data in scientific and practical works related to the cultivation of the juveniles of valuable salmonid species. Methodology. One-day free embryos (pre-larvae) of brown trout, rainbow trout and brook trout we used as study materials. Morphometric parameters we studied by the methods of N. O. Lange, E. N. Dmitrieva. The content of total lipids was determined in accordance with Folch. in the tissuesm, which were taken for biochemical studies. Separate classes of lipids were received by thin layer chromatography. Findings. We carried out a comparative analysis of morphometric measurements and biochemical parameters of one-day pre-larval brown trout, rainbow trout and brook trout based on the obtained data. We investigated morphometric and biochemical specific features of pre-larvae in post-embryonic period and showed the species differences of morphometric measurements. Significant differences were observed between the content of lipids in the body and yolk sac of free embryos. In particular, a higher content of phospholipids and triglycerides was observed in the body of brook trout compared to brown trout. We also recorded higher contents of mono- and diacylglycerols, free cholesterol, non-etherified fatty acids (NEFA), triacylglycerols and cholesterol esters in the yolk sac of brook trout. Compared to brown trout, rainbow trout had a significant increase in mono- and diacylglycerols, free cholesterol and NEFA in both body and yolk sac as well higher levels of total lipids, triacylglycerols and cholesterol esters were registered in yolk sac. Originality. For the first time we carried out and compared the specific features of pre-larval brown trout, rainbow trout and brook trout in the post-embryonic period. Practical value. The results will be used for further comparative studies and monitoring as well as for establishing the rates of linear growth and weight, lipid metabolism of fish species and for providing practical recommendations for increasing the efficiency of salmonid juveniles.