Acclimatization of fish to the higher calcium levels in the water environment

Abstract

It is established that calcium concentration changes (variations) in the water environment significantly influence its intake and distribution in tissues and organs of hydrobionts. The decrease in calcium concentration in water from 100 to 60 mg.L-1 significantly reduces its content in fish liver. In the gills glandular apparatus of fish acclimated to the environment with lower calcium level (in comparison with control one), its concentration on the first day of the acclimation period slightly exceeded the initial level, thus testifying to its possible excretion of endogenous calcium by gills. The increase of calcium excretion through the renal and digestive systems in fish acclimates to the higher water level, and specific changes in phosphates excretion dynamics accompany oral intake. Long keeping fish in water with 100 mg.L-1 calcium is accompanied by the increase of total phosphorus in urine (by 2 – 2.5 times), and its day excretion increases by 1.9 – 2.4 times. During fish acclimation to higher calcium levels in the water environment, the excretion of total phosphorus with faecal matter increases. The increase of calcium in the water environment to 100 mg.L-1 leads to a temporary increase in total phosphorus excretion with faecal issues. The rise in cation concentration to 200 mg.L-1 increases significantly during long-time fish stay in such an environment.

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“…However, it should be noted that the opinion of researchers regarding the dependence between the absorption of phosphorus from the aquatic habitat and its level in it is somewhat contradictory. Thus, (Dilelis et al, 2021;Hrynevych et al, 2022) had been shown that with phosphorus concentration increases in the aquatic environment, its accumulation by fish also increases. At the same time, a high number of phosphorus can adversely influence the branchial membranes, thereby reducing the actual absorption and phosphorus transport (Villeger et al, 2017).…”

Organization of distance learning using the Moodle platform, the Zoom service, and Google digital tools for higher education students of the Aquatic Bioresources and Aquaculture educational programs at Bila Tserkva National Agrarian University

“…Використання дистанційного навчання впродовж останніх років вказує на достатньо високу, якісну успішність здобувачів вищої освіти та підготовку науково-педагогічного персоналу для забезпечення освітньої програми Водні біоресурси та аквакультура у Білоцерківському національному аграрному університеті. Студенти забезпечені електронними варіантами посібників, підручників, курсів лекцій, презентацій, наукових публікацій за тематикою курсу на платформі Moodle (Kofonov et al, 2020;Vodianitskyi et al, 2020;Prychepa et al, 2021;Hrynevych et al, 2021;2022;Liasota et al, 2023).…”