Analytical control of protein and amino acid (AA) contents of animal tissues is an important problem in the fundamental and applied aspects. The aims of the work were the following: to measure the pig blood AAs; and to establish the correlations between AAs and biochemical parameters in dependence on the pig fattening duration. All 80 animals were divided onto 4 animal groups: 65, 72, 82, and 90 fattening days. The correlations between AAs and the total protein or its fractions (TP&F), nitrogen metabolites, carbohydrates, lipids, some enzymes in the pig blood for each of these animal groups obtained for the first time. The authors established the following total amounts of correlation coefficients (with reasonable p-values) in each of the group separately: group 1, 1* (p < 0.05); group 2, 0; group 3, 28* (p < 0.05) and 9** (p < 0.01); group 4, 28* (p < 0.05) and 25** (p < 0.01). Thus, about 82–90 days (groups 3 and 4) can be the optimal for the pig fattening, based on the correlation analysis for the numerous data of major AA and biochemical parameters of pig blood. These results can be useful for animal health monitoring and husbandry.

Goats are ubiquitous, including in hot and dry regions, while also being very sensitive to climate fluctuations, expressed in temperature differences. This affects their productivity and milk quality. Adaptation to heat requires high energy costs, affects “neurohumoral” regulation and is accompanied by oxidative stress with the increased production of free radicals. The aim was to study the main biochemical parameters of goat milk and its antioxidant activity depending on the season of the year. Sampling was carried out in April, June, August and October. Analysis of the biochemical components and antioxidant activity of goat milk was performed using modern analytical systems. From spring to autumn, the mass fraction of true or crude proteins in goat milk increased by 14.6–63.7% or by 12.3–52.1%, and the mass fraction of caseins also increased by 13.6–60.6%. For vitamin C level and the total amount of water-soluble antioxidants, a pronounced gradual decrease from spring to autumn was observed. In the summer period, a small increase in the carotene level in milk (by 3.0–6.1% compared to April) was established. Vitamin A content increased by 86.5% (June) or by 70.3% (October) compared to April. Thus, the numerous significant changes in the major parameters of goat’s milk depending on the season were revealed.

THE EFFECT OF DIFFERENT CLASSES OF TANNINS ON METHANOGENESIS IN RUMINANTS (review) N.S. Kolesnik , N.V. Bogolyubova, A.A. Zelenchenkova

The research was carried out to study an effect of the antioxidant melanin in the broiler nutrition on the chemical composition, antioxidant and technological properties of meat, and the fatty acid composition of abdominal fat. The experiment was conducted in the conditions of the physiological courtyard of the L. K. Ernst Federal Research Center for Animal Husbandry in 2023. Broilers (n = 27, N = 54) of the domestic broiler cross “Smena-9” were divided into two groups (control and experimental). Broilers of the control group were fed the basic diet, birds of the experimental group received the basic diet with the addition of water-soluble melanin at a dose of 1.42 mg /kg of bird weight from the 7^th to 45^th day of age. At the age of 45 days, the birds were slaughtered and the meat chemical composition, fatty acid content, and quality characteristics were determined. The addition of melanin to the diet led to an increase in the meat antioxidants in the breast by 18.75% (p < 0.0001) and in the thigh by 5.6%, and also resulted in an increase in reduced glutathione by 20.25%, glutathione peroxidase by 10.43%, catalase 17.35% in the breast compared with the control. The use of melanin in broiler diets contributed to an increase in the content of erucic and 8,11,14-eicosatrienoic acids in abdominal fat compared with the control (at p = 0.02 and p = 0.07, respectively), as well as to an increase in the moisture content in muscles and the enrichment of meat with the antioxidant.

Relevance. Goat milk is a valuable product in human nutrition. However, the diversity of biologically active compounds in its composition is subject to the influence of a variety of factors, including seasonal climatic changes.Materials and methods. Analysis of the biochemical parameters of goat milk was performed using the MilkoScan 7/Fossomatic 7 DC analytical system (Denmark) and MilkoScan 7, a spectrophotometer based on Fourier transform infrared spectrophotometry. Statistical processing of the obtained results was carried out in the «Microsoft Excel» program using the Data Analysis package. The significance of differences between seasons was assessed using the critical values of Student's t-test.Research results. Significant differences were established between True Protein in June 3.06 ± 0.07% (p ≥ 0.01), August 3.17 ± 0.12% (p ≥ 0.05) relative to October 4.37 ± 0.15%. Total Protein in April 2.92 ± 0.05% (p ≥ 0.01), June 3.28 ± 0.06% (p ≥ 0.001), August 3.37 ± 0.11% (p ≥ 0.01) relative to October 4.44 ± 0.14%. SOMO in April 8.17 ± 0.10% (p ≥ 0.05), June 8.42 ± 0.10% (p ≥ 0.001), August 8.39 ± 0.16% (p ≥ 0.001) relative to October 9.75 ± 0.14%. Caseins in April 2.21 ± 0.06% (p ≥ 0.01), June 2.51 ± 0.06% (p ≥ 0.001), August 2.56 ± 0.09% (p ≥ 0.001) relative to October 3.55 ± 0.12%. Seasonal changes most often occur in the composition of milk proteins: the mass fraction of true and total protein, caseins.

The purpose of the research was to study the content of ceruloplasmin, copper and copper-coordinating amino acids (in the molecule of the studied protein) in the milk of white-and- black cows at different periods of lactation. The research methods were: modified method for determining ceruloplasmin by Revin; copper was determined using a ZEEnit 650 P atomic adsorption spectrometer (Analytik Jena AG, Germany), amino acid analysis was performed using a highly efficient LC-20 Prominence liquid chromatography system (Shimadzu, Tokyo, Japan) equipped with a reaction module for post-column derivatization with ninhydrin ARM-1000 (Sevko & Co., Moscow, Russia). The study groups were formed depending on the timing of lactation: 1-2 months – group 1; 3-5 months – group 2; 6-7 months – group 3; 8-9 months – group 4. Each group included 8 animals. The Mann-Whitney U criterion and Pearson correlations were used for statistical processing of the obtained results. The average values of ceruloplasmin levels in the groups were 0.44-0.49 mg/ml, copper 71-83 mcg/l, histidine 0.11-013 g/100g, cysteine 0.03 g/100g and methionine 0.09-0.11 g/100g. In these 4 groups, small differences were found in the content of ceruloplasmin, copper and three amino acids, but only for the second and fourth groups of histidine, these differences were significant. Thus, the indicated intervals of ceruloplasmin and copper content can serve as important guidelines for determining the "reference intervals" for cow milk in general, while it is not necessary to take into account different lactation periods.