Volume 23(1), 2024

Abstract. This work aimed to assess the impact of ageing on the muscle microstructure of the biceps brachii (BB) and quadriceps femoris (QF) in dogs. The age-related impact on muscle capillarization (microvascularization) and the ability to regenerate muscle fibres was evaluated by calculating the number of satellite cells in dogs. It has been proven that there was no change in the percentage of each type of muscle fibre in the muscles tested. The observed tendency to increase the percentage of oxidative fibres, especially in the case of the BB muscle, may indicate that the oxidative capacity of skeletal muscles did not decrease with age. In both examined muscles, the highest number of capillaries was found in the group of dogs from 1 to 5 years old, and it differed significantly from the group of the youngest (up to 1 year) and the oldest (over 10 years) dogs. The youngest dogs had the highest number of normal muscle fibres and the lowest percentage of pathological changes in the BB and QF muscles. In the process of ageing, the share of atrophic fibres and connective tissue in muscles increases. Due to a decrease in the degree of vascularity and the number of satellite cells, ageing dog muscles show a lower regenerative potential, and thus a tendency to increase the number of pathological changes.

Abstract. The aim of the present study was to analyze blood morphological and biochemical indicators in Ukrainian Black-and-White dairy heifers (3, 6, 12, and 18 months of age and 8–9 months of gestation) and cows (2–3 months of the first lactation) of different constitutional types. Control and experimental groups were formed based on the physiological-selection index (104 vs. 140 units, respectively). Erythrocyte level, the content of hemoglobin and total protein, the activity of aspartate aminotransferase and alanine aminotransferase, the content of total and residual sulfhydryl groups, the content of total and reduced glutathione, and catalase activity were significantly higher (P < 0.05) in the experimental group (by 7.92%, 7.64%, 8.09%, 11.78%, 12.21%, 18.34%, 24.34%, 9.66%, 9.56%, and 7.60%, respectively). Thus, based on the main indicators of biochemical processes in the organism, it can be stated that animals with a higher physiological-selection index significantly exceeded those with a lower value of this index. This indicates that metabolic processes in the experimental animals proceeded much more intensively than those in the control group.

Abstract. The study analyzed 180 longissimus lumborum muscle samples with varying pH levels, collected from the carcasses of 180 six-month-old crossbred fattening pigs with an average weight of 91.3 ± 6.8 kg, slaughtered on an industrial processing line. The analysis included the determination of moisture content, crude protein, intramuscular fat, ash, hematin content, water holding capacity (WHC), and pH_u. Color measurements were conducted using the CIELAB and CIELCh color scales and the D65/10° illuminant/observer system. Reflectance was measured in the 400–700 nm range, and the chromatic absorbance at a wavelength of 525 nm (A_525p) as well as the relative quantities of MbO₂, MetMb, and Mb were calculated. The results indicated that all color parameters, except for hue angle (h°), were significantly influenced by total moisture, crude protein, and intramuscular fat content, as well as pH_u and WHC, but were not dependent on hematin content. In contrast, all color parameters except for yellowness (b*) – namely lightness (L*), redness (a*), chroma (C*), and hue angle (h°) – were significantly affected by chromatic absorbance at 525 nm (A_525p), which reflects the quantity of pigments exposed to light. Additionally, the relative quantity of myoglobin chemical forms significantly influenced all color parameters, with the strongest effect observed for yellowness (b*). The relationships between chromatic absorbance at 525 nm (A_525p) and relative myoglobin chemical form quantities, determined spectrophotometrically, provide a satisfactory explanation of the variation in chromatic color parameters.