This article presents the findings of a study on the peculiarities of mineral metabolism in sheep when incorporating soybean processing products (soybeans, soybean cake, soybean forage, and soybean meal) into their diet. A comparative analysis of calcium and phosphorus bioavailability was conducted in rumen fluid, duodenal chyme, and blood serum of Kuibyshev sheep fed a hay-concentrate diet, with 15% of the concentrate portion replaced by the specified soybean products. The chronic physiological experiment method with fistulation techniques was employed to assess macronutrient metabolism across the digestive tract. It was found that rumen microflora, producing the enzyme phytase, enhances phosphorus bioavailability, while the acidic environment of the duodenum facilitates calcium absorption. Diets with soybeans and soybean cake increase calcium levels in rumen fluid by 26.7% and 40%, respectively, compared to the control diet, while forage reduces it by 18%; phosphorus levels decrease by 2–11% across all soybean diets. In duodenal chyme, the calcium-to-phosphorus ratio is 2:1, but calcium content is 5–11% lower than the control diet depending on the product. In blood serum, the optimal calcium-to-phosphorus ratio (2:1.2–2:1.5) is maintained, except for the soybean diet (2:1.8). The highest calcium bioavailability in blood is observed with soybean cake (2.62±0.11 mmol/l), and phosphorus peaks with soybeans (2.06±0.11 mmol/l). The forage diet shows the lowest calcium concentration in the rumen, while the meal diet reduces mineral levels in blood due to the formation of insoluble compounds. The results highlight the impact of soybean product processing on phytate and oxalate solubility and provide insights for optimizing sheep diets.

Karamushkina Svetlana V., Zhevnerov Alexey V.

1. Volnin A. A. Physiological and biochemical characteristics of interspecific hybrids of Romanov sheep and argali. Candidate's thesis. Bogolyubovo, 2019, 150 p. (in Russ.).
2. Bogolyubova N. V., Bagirov V. A., Zinovieva N. A. Features of mineral metabolism in hybrid sheep of Romanov breed with argali (Ovis ammon). Dostizheniya nauki i tekhniki APK, 2018;32;7:52–55. doi: 10.24411/0235-2451-2018-10712. EDN XYUKGD (in Russ.).
3. Karamushkina S. V., Vadko A. V. Prospects for the use of soybean production waste in sheep farming. Proceedings from Agro-industrial complex: problems and prospects of development: Vserossiiskaya nauchno-prakticheskaya konferentsiya. (PP. 52–55), Blagoveshchensk, Dal'nevostochnyi gosudarstvennyi agrarnyi universitet, 2021 (in Russ.).
4. Köhler O., Grünberg W., Schnepel N., Muscher-Banse A., Rajaeerad A., Hummel J. [et al.]. Dietary phosphorus restriction affects bone metabolism, vitamin D metabolism and rumen fermentation traits in sheep. Journal of Animal Physiology and Animal Nutrition, 2020;104;6:1902–1914. doi: 10.1111/jpn.13449.
5. Vötterl J., Klinsoda J., Zebeli Q., Hennig-Pauka I., Kandler W., Metzler-Zebeli B. Dietary phytase and lactic acid-treated cereal grains differently affected calcium and phosphorus homeostasis from intestinal uptake to systemic metabolism in a pig model. Nutrients, 2020;12;5:1542. doi: 10.3390/nu12051542.
6. Kızılaslan M., Arzık Y., Behrem S., Yavuz E., White S., Cinar M. Unravelling the genetic architecture of serum biochemical indicators in sheep. Genes, 2024;15;8:990. doi: 10.3390/genes15080990.
7. Litvinenko O. V., Korneva N. Yu., Kodirova G. A., Kubankova G. V. Results of comparative study of soybean varieties by biochemical composition of grain. Agronauka, 2023;1;4:62–70. doi: 10.24412/2949-2211-1-4-62-70. EDN ALUMFX (in Russ.).
8. Tapia J., Leib S., Marini P., Fischman M. Effect of mineral supplementation on the macromineral concentration in blood in pre- and postpartum blackbelly sheep. Animals, 2020;10;7:1206. doi: 10.3390/ani10071206.
9. Toral P., Hervás G., Frutos P., Yáñez-Ruiz D., Belenguer A., Bati M. Impact of oxalic acid on rumen function and bacterial community in sheep. Animal, 2013;7;6:940–947. doi: 10.1017/S1751731112002455.
10. Spears J., Brandao V., Guimaraes O., Wagner J., Engle T. Trace mineral source influences digestion, ruminal fermentation, and ruminal copper, zinc, and manganese distribution in steers fed a diet suitable for lactating dairy cows. Animal, 2022;16;4:100500. doi: 10.1016/j.animal.2022.100500.
11. Gbamwuam D., Francis A., Tsenum J. Evaluation of soybean varieties for oxalate, phytate and polyunsaturated fatty acids content. Science Open Preprints, 2020;12:1–67. doi: 10.14293/S2199-1006.1.SOR-.PPPZPXC.v1.
12. Waldron K., Arrutia F., Williams P., Binner E. Oilseeds beyond oil: Press cakes and meals supplying global protein requirements. Trends in Food Science & Technology, 2020;100:336–348. doi: 10.1016/j.tifs.2020.03.044.
13. Zhang R., Gao K., Shi J., Xue S., Sun H., Di D. [et al.]. Exploring the dual role of antinutritional factors in soybeans: a comprehensive analysis of health risks and benefits. Critical Reviews in Food Science and Nutrition, 2024;11:1–18. doi: 10.1080/10408398.2024.2430757.