The influence of dietary vanillin and quercetin on the macro- and microelement status of cattle

The use of secondary plant metabolites (phytobiotics) as an alternative to antibiotics in cattle feeding avoids the appearance of negative factors in the final meat product. The introduction such substances into the bulls feed affects the bacterial communities of the rumen contents, the processes of digestion and assimilation of the components of the diet. In this work, for the first time, the elemental profiles of the ruminal contents, blood serum, feces, and urine of bulls were comprehensively evaluated when a combination of quercetin and vanillin was added to the diet, and the elemental load coefficients of these biomaterials were determined. The aim of the work was analyzing of the dynamics of the elemental profile of essential, conditionally essential, toxic and potentially toxic elements in the rumen fluid, feces, urine and blood serum of cattle when a combination of phytochemicals vanillin and quercetin is included in the diet. The work was carried out in 2024. Bulls ( Bos taurus L.) of the Kazakh white-headed breed (age 13 months, weight 320-340 kg) were divided into two groups by the method of pairs of analogues ( n = 3). The bulls of the control group received a basic diet (30 % concentrates and 70 % coarse feed). The calves of the test group, together with the main diet, received a combination of phytochemicals vanillin + quercetin (Acros Organics, Belgium), which were mixed with a concentrated part of the diet and distributed individually to each animal, in the morning. Vanillin was used at a dosage of 1.5 mg/kg of the concentrated part of the diet, quercetin at a dosage of 5.9 mg/kg of the concentrated part of the diet. The balance experiment was conducted in two periods: preparatory (10 days) and accounting (8 days). During the preparatory period, the feed consumption was clarified, and the animals were accustomed to equipment useed to collect urine. During the reference period, a continuous collection of feces and urine was carried out, the daily amount of which was weighed, thoroughly mixed, and average samples were taken: feces - 3 %, urine - 5-10 % of the total amount. Feces were preserved with chloroform, urine with thymol. The animals were diagnosed with chronic rumen fistulae. Rumen contents were sampled in sterile gloves in a thermos with a constant temperature to preserve the microbiome. Blood samples were taken from the subcostal vein with sterile needles into vacuum tubes with EDTA and coagulation activator. The collected feces were dried at 60 °C for 6 hours, then at 105 °C to a constant weight, and analyzed in native form. Hay and concentrates were dried to an air-dry state and crushed. Urine, blood serum, and rumen fluid were stored frozen (at a temperature of -20 °C) and analyzed in native form. The total content of Na, Mg, P, K, Ca, Mn, Cu, Se, Mo, I, Cr, Fe, Zn, Co, Li, V, Ni, As, B, Br, Al, Ba, Bi, Hg, Pb, Tl, Be, Sr, Sn, Sb, Cd, and Ag were determined by inductively coupled plasma mass spectrometry on an Agilent 7900 ICP-MS kinetic energy discrimination single-quadrupole mass spectrometer (Agilent Technologies, Inc., USA), having previously destroyed the organic matrix by wet ozonation in a microwave sample preparation system. An assessment of the total toxic load index relative to the control samples was carried out. With a coefficient value of 1, the element load of the experimental and control groups is the same; with values >1 and function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }