Fiziološke uloge, farmakokinetika i farmakodinamika niacina kod krava

Vitamin B3 (Niacin, Vitamin PP) is a combination of two chemical structures, nicotinic acid, i.e. niacin and nicotinamide. Niacin is not classified directly as a vitamin because the body synthesizes it under normal metabolic conditions and almost completely satisfies the body's needs. Considering that for its production in cows it must have enough tryptophan and there must be sufficient food intake and conditions in the rumen, niacin is a very important vitamin that must be supplemented. Niacin is extremely important for a large number of metabolic and energetic activities, and the precursor of niacin is the amino acid tryptophan. The biochemical function of nicotinic acid and nicotinamide is realized through the function of coenzymes, because these vitamers are included in the composition of coenzymes NAD+ and NADP+, which are components of about 150 different enzymes, hence the importance of niacin for energy metabolism. More important metabolic processes that are linked to the influence of niacin through coenzymes are anabolic processes such as the synthesis of nucleic acids and lipids, where NADPH is the reducing agent. In catabolic processes, it should be emphasized the participation of NAD in a greater number of oxidation-reduction reactions, in which the role of NAD is to transfer electrons from the highest energy level, which is what thesereactions are known for. Niacin shows antilipolytic action, affects carbohydrate metabolism and reduces insulin resistance, and has an anti-inflammatory effect. All of the above indicates that niacin is important in cows under metabolic stress, so this paper describes its pharmacokinetics and pharmacodynamics in detail.