Metabolic and antioxidant profile of Nubian and Karachay goats (Capra hircus L.)

When assessing animals’ health status under different physiological conditions and under the influence of various factors, it is important to know the reference values of biochemical indicators and parameters of antioxidant defense. Furthermore, to understand the functioning mechanism of the antioxidant system elements in the body, we should investigate the nature of their correlation. This study has revealed for the first time that the metabolic and antioxidant profile in dual-purpose goat breeds depends on their age and on the number of lactations, as well as on the breeding area in relation to the altitude. With an increase in the number of lactations in animals, indicators related to oxidative stress increased, along with the activation of the antioxidant defense system. Our objective was to evaluate the biochemical and antioxidant status of goats depending on the breed and the number of lactations, as well as to determine the correlation between the biochemical parameters of blood and indicators of the antioxidant system of Karachay and Nubian goats. The study was conducted in 2023 on lactating Nubian ( n = 43) and Karachay ( n = 93) goats ( Capra hircus L.). Karachay goats belong to meat-milk breeds, while Nubian goats belong to milk-meat breeds. Animals of different breeds were divided into four groups according to the number of lactations (group 1, group 2, group 3, and group 4). Blood samples for the study were collected during the summer period. Karachay goats were kept on mountain pastures of the North Caucasus (1000 m above sea level), while Nubian goats were kept in the forest-steppe zone of the Moscow region (180 m above sea level). The former were raised in the pasture-stall system and the latter in the stall-pasture system. The diets of goats, consisting mainly of bulky feeds, did not contain components with pronounced antioxidant properties. Biochemical blood parameters were determined using the ChemWell automatic analyzer (Awareness Technology, USA) with reagents from Analyticon Biotechnologies AG (Germany), Spinreact S.A, (Spain), and AO Diakon (Russia). Lipid peroxidation biomarkers were identified based on the concentration of products reacting with thiobarbituric acid (TBA-AP) with kits from OOO Agat-Med (Russia). Antioxidant defense was determined by ceruloplasmin (CP) activity using Revin’s method. The total amount of water-soluble antioxidants (TAWSA) was assessed by the amperometric method on the Color Yauza-01-AA device with a detector (NPO Khimavtomatika, Russia). The TBA-AP/CP ratio was calculated. Statistical analysis of the results was carried out using the software package Microsoft Office Excel 2003. The influence of factors on the variability of characteristics was assessed using multivariate analysis of variance (MANOVA) with generalized linear models (GLM). We found that breed origin significantly affects the concentration of urea, bilirubin, phosphorus, ceruloplasmin, and, to a lesser extent, the activity of alanine aminotransferase (ALT), the content of calcium, TBA-AP, total protein, globulins, phospholipids, and cholesterol. The blood of Karachay goats had a higher content of total protein, globulins, urea, a higher ALT activity, a higher concentration of total bilirubin, calcium, phosphorus, TBA-AP, and the TBA-AP/CP ratio (4.96 to 85.90 %, p ≤ 0.05, p ≤ 0.001), while that of Nubian goats was higher in ceruloplasmin (80.0 %, p ≤ 0.001), cholesterol, and phospholipids (8.64 and 9.58 %). The study identified the dynamics of biochemical indices and indicators of antioxidant defense for dual-purpose goat breeds depending on the number of lactations. The indicators of protein metabolism and magnesium content in blood serum were minimal during the first lactation and maximal during the fourth lactation. The activity of aspartate aminotransferase (AST), the concentration of TBC-AP, the TBC-AP/CP ratio increased significantly during the second lactation. Then, during the third and the fourth lactations, they decreased to the values of the first lactation. The differences in phosphorus concentration, ceruloplasmin and alkaline phosphatase activity were the opposite: decreasing in the second lactation and increasing in subsequent lactations. TAWSA was higher during the first two lactations and decreased in the third and fourth lactations. The nature of changes in the content of TBA-AP and antioxidant defense indicators (TAWSA and CP) showed the specifics of their interaction to ensure antioxidant homeostasis in goats of different ages.