The aim of our study was to investigate the effect of different forms of calcium in the diet of broiler chickens on morphometric parameters of the femur and tibia and on the elemental composition of bone tissue. In the experimental groups 20% of the calcium from the norm was replaced by the additives studied: the first group - calcium chloride, the second group - calcium citrate, the third group - dolomite flour. Then, the production and osteometric indicators, as well as the elemental composition of biosubstrates were assessed. Based on the data obtained, we concluded that highly accessible and soluble calcium sources, such as calcium chloride and citrate, can significantly improve bone health. Replacing the traditional calcium source, limestone flour, with calcium chloride improves the elemental composition of bones - increasing phosphorus and calcium levels. This, in turn, has a positive effect on bone morphometric and density parameters. The proposed strategy can promote optimal skeletal development of fast-growing broiler chickens, allowing them to adapt successfully to increasing body weight. Given the economic and social significance of this issue, such diet modification can become one of the key metabolic factors in solving the problems of non-infectious skeletal disorders.

Background and Aim: The existing data demonstrate that gut microbiota is involved in regulating mineral metabolism in cattle, although the data are quite contradictory. The study aimed to evaluate Saccharomyces cerevisiae-based probiotic’s effects on gut microbiota, systemic metabolism, and dairy cows’ essential trace element and mineral body burden. Materials and Methods: Fifteen cows received a daily supplement of a 50 g S. cerevisiae-based probiotic, fortified with methionine, choline, eugenol, cinnamaldehyde, and Capsicum oleoresin, for a month. 16S metagenomic sequencing was used to evaluate the taxonomic features of fecal microbiota. Serum trace elements and minerals levels were determined through inductively coupled plasma mass spectrometry. Results: Supplementation with S. cerevisiae-based probiotic complex significantly increased alpha and beta diversity, as well as the abundance of Mediterranea and Clostridium IV within the Bacillota phylum, whereas that of Bacteroidota and specifically unclassified Bacteroidales and unclassified Oscillospiraceae decreased. Following probiotic supplementation with the S. cerevisiae-based complex, gut microbiota modulation led to a significant boost in circulating levels of calcium, copper, selenium, and zinc. Creatinine levels decreased while total cholesterol levels increased within normal limits in the serum analysis. Conclusion: The observed improvement in trace elements and minerals in dairy cows might be due to changes in intestinal microflora caused by supplementation. Therefore, probiotic supplementation in cattle may be considered a potential tool for improvement of mineral nutrition in cattle. However, the influence of probiotic treatment and modulation of mineral metabolism on milk productivity and overall performance in cattle is yet to be estimated. Keywords: gut microbiota, minerals, probiotic, Saccharomyces cerevisiae, trace elements.

Poultry farming is one of the most important and promising branches of animal husbandry. Given the increasing rate of industrial poultry farming, for the stable development of the industry and improving competitiveness in world markets, more and more attention is paid to the search for safe alternative agents to increase productivity. The study examined the strategy of feeding substances of different nature as feed additives, in particular, enzyme complexes separately (group I (0,05%; endo-1,4-beta-xylanase - 4000 units/g, alpha-amylase - 400 units/g and subtilisin - 8000 units/g)) and in combination with ultradispersed zinc (group II (3 mg/kg; 164±31,2 nm)). It was found that in group I the digestibility ratios of crude protein were higher by 6.03 % (P≤0.05), crude fiber by 3.68 % (P≤0.05), nitrogen-free extractive substances by 2.39 % (P≤0.05) compared to control. At the same time, in group II, changes were recorded in crude protein and crude fiber - an increase of 6.51% (P≤0.01) and 7.59% (P≤0.05), respectively. At 42 days of age, the live weight of broiler chickens I was 10.1% higher than control (P≤0.05), and in group II by 11.32% (P≤0.01). At the same time, the cost of feed per 1 kg of growth was minimal in group II, 16.79% lower than the control values. Thus, the maximum productive effect was observed with the introduction of a complex enzyme supplement in combination with zinc in ultradispersed form.