Features of nitrogen metabolism in fishes

Abstract

Presence in water is easily metabolized nitrogen-containing substances is a vital condition for the existence of food organisms in ponds used for fish reproduction. At the same time, the end products of nitrogen metabolism-ammonia, nitrites and nitrates are always displayed the body of fish into the environment, adding to the total number of these compounds dissolved in water. Ammonia, nitrite and nitrate anions are formed during biological processes, as well as man-made origin, have toxic properties and are considered as environmental factors that may limit fish productivity of reservoirs. The results of a brief review of the literature showed that the features of nitrogen metabolism in fish are actual direction of research, both theoretical science and in practical fish farming. Published the results of studies of amino acid metabolism in fish suggest that, firstly, the processes responsible for the neutralization and the release of ammonia from the body of fish, as well as ontogenetic aspects of the dynamics of formation and emission of ammonia is not fully understood. Meanwhile, several authors stressed the importance of this area of interest for the formation of science-based ways to improve the efficiency of plant breeding in fish culture. Secondly, endogenous nitrite, being the product of oxidation of the molecule nitric oxide and its transport form, the norm are always present in fish. However, the mechanisms responsible for maintaining the stability of the concentration of nitrite in the internal environment of fish, not well understood. Also, in our opinion, of interest to determine the physiological rules of nitrites and nitrates in the body of various species, depending on the seasons and stages of ontogeny. Thirdly, the literature pays much attention to the toxic properties of nitrite in water biocenosis. Certainly, the analysis of the manifestation in fish tissue-specific toxic effects of nitrites and their derivatives-an important area of research. Nevertheless, we can not exclude that it may be quite promising analysis of the incorporation of exogenous nitrite as a substrate exist in fish of the physiological mechanisms re-synthesis of nitric oxide. This kind of ''interference'' of endogenous and exogenous nitrite-anions are not causing serious structural damage to organs and tissues, however, can cause substantial damage to the practical fish farming, causing changes in the level of regulatory mechanisms of fish at the most critical stages: when working with manufacturers, the incubation of eggs, and larvae rearing and wintering fish.

Peptide Transporters in the Primary Gastrointestinal Tract of Pre-Feeding Mozambique Tilapia Larva

“…Protein is an important nutrient in fish diets, as it supports energetic supply for physiological processes and growth, in addition to tissue and protein construction (Sire and Vernier, 1992; Dolomatov et al, 2011). In addition to being an energetic source and building blocks for proteins, amino acids also play an important role in many physiological processes such as signaling and gene expression (Wu, 2010).…”

Resveratrol Induces Expression of Metabolic and Antioxidant Machinery and Protects Tilapia under Cold Stress

“…Oxygen consumption rate of intact fish in the rest condition is regarded as a suitable parameter to reflect metabolic rate, which indirectly indicates overall energy demand. Additionally, catabolism of amino acids is a major energy source in fishes, since most are ammonotelic [46,47]. Therefore, changes in O:N ratio provide a reliable indicator of corresponding changes in the utilization of different energy substrates [48].…”

Standards for environmental flow verification

“…Changes in fish species reflect changes in aquatic ecosystems, and the disturbance of fish communities caused by river water pollution affects the e‐flow evaluation and verification. The water quality factors that have the strongest impact on fish include ammonia nitrogen, nitrate, and nitrite levels (Dos Santos Silva et al, 2018; Dolomatov, Shekk, Zukow, & Kryukova, 2011). Therefore, the fuzzy clustering method (Zhao et al, 2017) classifies stations into three levels of the water quality impact (large, small, and none) according to these three criteria.…”