Evaluation of trypsin in the duodenal contents and blood of chickens by biochemical and molecular genetic methods

The study is devoted to the assessment of trypsin activity in the duodenal contents and blood of Hisex White laying hens using biochemical and molecular genetic methods. The aim of the work is to study the enzymatic activity of trypsin and the expression of its genes (PRSS2, PRSS3) depending on the composition of the diet. The experiments were carried out on hens with chronic duodenal fistula, whose diet complied with the standards of VNITIP (17.7% crude protein, 282 kcal/100 g). All studies on poultry were carried out in accordance with the requirements of humane treatment of animals (European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes (ETS No. 123) [Russian, English] (Strasbourg 18.03.1986). Trypsin activity in duodenal chyme 60 and 120 minutes after feeding was 2249±118.6 and 2368±122.1 U/L, respectively, indicating adaptation of the pancreas to the protein component of the feed. In blood serum, trypsin activity reached 298±59.9 U/L, which is 7.5 times lower than in the intestine, but indicates a high level of metabolism. Molecular genetic analysis confirmed the expression of the PRSS2 and PRSS3 genes in the duodenal contents and PRSS3 in the blood, with the activity PRSS3 in the blood was higher than in the intestine. A correlation was established between trypsin activity in biological fluids and metabolic processes, including protein and lipid metabolism. The results emphasize the role of trypsin as a marker of metabolism and its regulatory functions, which is important for optimizing diets and assessing the selection indicators of poultry.