Prospects for fistula technologies in the study of digestion and metabolism in birds

Vladimir Vertiprakhov¹Sergei Yu. Zaitsev^2*

• ¹Rossijskij gosudarstvennyj agrarnyj universitet MSHA imeni K A Timirazeva, Moscow, Russia
• ²Federal Research Center for Animal Husbandry named after Academy Member L.K. Ernst, Moscow region, Russia

For developing more effective feeds and feeding methods for farm birds, it is important to study digestion and metabolism processes usinf fistula technologies. This approach has an unconditional ethical priority over post-mortem collection of research material. Furthermore, a positive aspect is the ability to regularly obtain contents from a healthy living organism multiple times at specific intervals in a single animal to determine the dynamics of different phases of the secretory process, and all in real time. Another positive aspect is the use of modern methods for determining enzyme activity, which allow for an objective assessment of the adaptation process to the intake of nutrient substrate into the digestive tract and comparison with a "baseline period". This also allows direct comparison of enzyme activity in the digestive system and in the blood serum. All of these positions are important for determining the subtle mechanisms of regulatory processes in the bird's body, the specific effects of various feed additives, and the reactivity of adaptive responses in assessing selection indicators. vitamins. In the cecum, carbohydrates not exposed to microorganisms in the small intestine are 39 fermented, as in mammals, to form volatile fatty acids. It is supposed that the birds cannot utilize 40 microbial proteins in their caecum. Significant water absorption occurs in the rectum and cloaca. Bird 41 feces typically contain some white uric acid crystals. The cloacal wall contains the "bursa of Fabricius", 42 an important lymphoid organ. Overall, the bird intestine serves not only as a digestive system but also 43 as a barrier to immune complexes and other factors (Batoev,2001 and intestines is considered the most 48 promising method. For example, the problem of obtaining pure gastric juice in a chronic experiment 49 in ducks was successfully solved first by Berdnikov (1990). The author adopted I.P. Pavlov's classical 50 method of creating an isolated stomach for mammals as a basis, taking into account the 51 morphofunctional characteristics of birds. The surgical procedure involves preserving the innervation 52 of the small ventricle by dissecting a section of the vagus nerve in the area of the gastric flap resection, 53 which will later be used to create the isolated ventricle. The gastric wall flap is dissected 54 circumferentially through all layers, including the dissected nerve, and the small ventricle is sutured. 55The ventricle is supplied with blood via the dorsal gastric artery and innervated by a branch of the 56 vagus nerve. The ventricle is secured to the large ventricle with a suture. A cannula inserted into the 57 isolated ventricle is brought out and secured to the skin with a purse-string suture (Fig. 1). Using this method for obtaining gastric juice in ducks, the patterns of gastric juice secretion and its 59 regulatory mechanisms were studied. The conditions for the adaptation of gastric glands to changes in 60 diet were determined. Data on the functional relationships of the digestive glands were presented 61 (Berdnikov et al., 2012). One method for obtaining pure pancreatic juice in chickens 62 is cannulation of the pancreatic duct (Hulan et al., 1972). A surgical technique for cannulation 63 of the main pancreatic duct in 14-week-old chicks has been developed. A silicone cannula is inserted 64 into the main pancreatic duct, the free end of which is removed through a puncture in the abdominal 65 wall and connected to a collecting tube made of polyethylene 90. The collection tube is then connected 66 to a tube that is placed in a thermos with ice when the operated chick is placed in the cage for fixation. It 67 was found that no special postoperative care was required. The pancreatic secretion was successfully 68 collected within 24 hours for three months after the catheter was placed. None of the chickens lost 69 weight, and most even gained weight during the experiment. Successful catheter insertion into the 70 pancreatic duct was performed in 90% to 95% of cases. A significant disadvantage of this method was 71 the further activation of proteases, since they are activated in the 12 denum. Batoev Ts.Zh. and 72 coworkers developed a fundamentally new method for studying the exocrine function of the pancreas 73 in poultry (Batoev,2001). It is based on the implantation of pancreatic ducts into an isolated segment 74 of the intestine and the formation of a pancreaticoduodenal anastomosis (Batoev,2001). 75 2In review to perform on poultry, so simpler and more effective methods are being developed for chronic 86 experiments studying metabolic pathways involving digestive enzymes. This requires inserting a 87 cannula into the duodenum opposite the confluence of the pancreatic and bile ducts 88 (Vertiprakhov,2022).89 Surgical procedures were performed using sedatives and anesthetics. The chicken was fixed in a left 90 lateral position in a special device. An incision was made on the right side of the last rib along the edge 91 of the lateral process of the sternum, 4-5 cm in length. The duodenum was removed, the entry of the 92 ducts into the duodenum was identified, and a 0.5-0.6 cm purse-string suture was placed opposite it. 93An incision was made within the purse-string suture, a cannula was inserted, and the purse-string suture 94 was tightened (Figs. 1). The area around the implanted cannula was carefully prepared, and an 95 additional purse-string suture was placed, if necessary. The intestine was placed deep into the 96 "thoracoabdominal" cavity, and the surgical wound was closed with interrupted sutures, covering all 97 layers. After the surgery, the bird had access to water for 16 -18 hours, but was not given food. Physiological experiments began in 5-7 days after surgery, when the bird's health had fully recovered. To study duodenal digestion and the role of pancreatic enzymes, the authors propose a method that is 100 significantly simpler to implement than the method proposed by (Batoev,2001). The method involves 101 inserting a cannula into the duodenum opposite the confluence of two bile ducts and three pancreatic 102 ducts (Vertiprakhov,2022). We have developed a specially designed cannula suitable for laying hens Nutrient absorption in the diet receives the greatest attention, as it significantly impacts animal 109 productivity. Birds are prone to ideal fistula formation. One method proposed for obtaining ideal 110 contents in poultry was proposed by Japanese scientists (Isshiki et al., 1989). Unlike the classical 111 method for determining fecal accessibility, such accessibility has its own unique properties ( Zhuravlev et al., 2020). Along with fistula technologies for studying digestion, it is necessary to simultaneously determine the absorption of amino acids and di-and tripeptides in the blood and analyze digestive en zymes in the blood (trypsin), which are biomarkers of animal metabolism (Pierzynowska et al., 2025). This provides a comprehensive and more objective approach to assessing the body's adaptive capabilities and the health of the digestive system. enzymatic activity allow for an objective assessment of the process of adaptation to the arrival of a 118 nutrient substrate in the digestive tract and comparison with the initial period, as well as the availability 119 of amino acids and di-, tripeptides in the blood and the level of metabolism using a biomarker-trypsin 120 activity in the blood in the pre-and postprandial periods. This allows for the determination of 121 regulatory processes in the bird's body and the mechanism of action of various feed additives, as well 122 as the reactivity of adaptive responses in assessing selection parameters when developing new animal 123 crosses while simultaneously comparing the expression of genes associated with metabolism.