The aim of this work was to compare the methods of malondialdehyde detection, as the main secondary product of the lipid peroxidation process, in meat and meat products. Malondialdehyde measurements were performed by two modified methods, the 2-thiobarbituric acid spectrophotometric method and the reverse-phase high-performance liquid chromatography in raw, mechanically-deboned chicken meat and in manufactured frankfurters. The malondialdehyde concentrations measured by the 2-thiobarbituric acid spectrophotometric method were found to be overestimated by more than 25% in raw meat and more than 27% in frankfurters in comparison to the results of reverse-phase high-performance liquid chromatography (p < 0.05). The achieved results showed that the presented modified reverse-phase high-performance liquid chromatography method was more applicable and more accurate for the quantification of malondialdehyde in samples of meat and meat products.

Multiple factor analysis was used for the examination of meat quality of broilers, the diet of which was supplemented with 0.8 and 1.0% addition of humic substances (HS). One hundred fifty COBB 500 one-day-old male broilers chicks were randomly divided into 3 different groups: one control and 2 experimental (n = 50), and they were fattened for 35 D. Subsequently, the meat quality was analyzed and defined by physicochemical and sensory quality, supplemented with analysis by instrumental methods. We observed changes in dry matter, fat, water, and protein content in experimental samples of breast and thigh meat (P < 0.001). In both experimental groups, the concentration of phosphates and pH decreased in breast meat (P < 0.001) and in thigh meat (P < 0.05). The smell of experimental chicken breast meat samples after cooking was evaluated by a sensory panel, which scored a higher point score than that of the control group (P < 0.05). Sensory evaluation of taste indicated a positive response with respect to the perception of meat quality in relation to a greater supplementation of HS in the diet. Thigh meat samples showed a variable extent of water loss after cooking, but lower values of water loss were generally obtained from thigh meat samples of poultry fed with higher HS supplementation, than in chicken breast meat samples. Significant differences in evaluated variables between both experimental groups were not observed. The color of breast meat samples changed, when considering the variables of lightness and redness, with the addition of 1% HS (P < 0.05). The main advantage of the breast meat of broilers fed a diet supplemented with HS was observed in the final meat quality, which was positively affected by increased protein and decreased fat content. Because of its nutritional composition, it can be considered to be rather a valuable type of meat in human nutrition than ordinarily.

Consumption of sheep’s and goat’s milk and cheese is currently increasing. The production process of these types of cheese is being carried out by traditional domestic production at farm level. However, knowledge in the field of hygiene, technology and health safety of cheeses are still insufficient. This study aimed to examine the physical and chemical quality and microbiological safety of sheep’s and goat’s milk and cheeses made from them. The month of milking influenced the content of milk components (p < 0.001) in sheep’s milk and goat’s milk, but no changes in SCC content during the examined period were found (p > 0.05). Level of contamination by Enterobacteriaceae sp. and coagulase-positive staphylococci was lower than 5 log CFU/mL in sheep’s and goat’s milk. During the ripening time, the number of lactic acid bacteria significantly raised (p < 0.001). Ripening time statistically changed (p < 0.001) not just the microbial safety of cheeses but also the color (p < 0.01). Under the applicable regulations, the analyzed samples were evaluated as suitable for human consumption.

Humic substances are currently being considered as a new feed component in replacement of antibiotic growth stimulators to improve growth and health in animals. The aim of our work was to evaluate the effect of the addition of humic substances to the feed at concentrations of 0.8% and 1.0% on the growth parameters, carcass yield, selected blood enzymes, minerals, and the bone quality in broiler chickens. One hundred fifty COBB 500 one-day-old male broiler chicks were randomly divided into one control and two experimental groups (n = 50) with three replications (16, 16 and 17 per pen), and fattened for 35 days. The broilers of the experimental groups (H0.8 and H1.0) were fed commercial feed mixtures with added humic substances (at 8 g·kg ^-1 and 10 g·kg ^-1 ). The control group was fed a diet without the addition of humic substances. A slight increase in the final body weight and feed conversion ratio was noted in the experimental groups ( P > 0.05). Significantly higher yields of breast and thigh meat ( P < 0.05) were recorded for the experimental group H1.0. The blood cholesterol level was lower for both experimental groups. A lower concentration of alkaline-phosphatase was observed in group H1.0. A decrease in aspartate aminotransferase and calcium was recorded for group H0.8. A significantly higher content of calcium and lower content of phosphorus was found in the bones of experimental animals. The 1% addition of humic substances had a positive impact on growth parameters ( P > 0.05), improved selected blood indices and increased the calcium content in the bones of broilers ( P < 0.05).

This study was conducted to examine the effect of two humic substances (HS) supplemented in broilers’ diet on the breast meat quality of broiler chickens. In this experiment, 120 pieces of one-day-old COBB500 broiler chickens were used. Broilers were divided into three groups, each containing 40 birds with three replications (13, 13, and 14 per one pen). Fattening lasted 38 days. The first experimental diet was supplemented with 0.7% of HS (HS0.7) and the second was enriched with 0.7% of acidified HS (HSA0.7). The control group of broilers (C) was fed a basal diet without the addition of any supplements. HS0.7 samples had the highest total protein content and the lowest content of fat (p < 0.01). The effects of broiler diet and storage had a significant impact on the pH of breast samples, p < 0.001 and p < 0.05, respectively. Supplementation of HS in broiler diet positively affected the lipid oxidation of breast meat samples, as indicated by the lower malondialdehyde content (p < 0.05). HSA0.7 samples had significantly better juiciness after the storage period (p < 0.001). The quality of meat produced with supplementation of HS in broilers’ feed can be considered as valuable in human nutrition due to improved protein and fat content with decreased lipid oxidation.

Humic substances with a high proportion of humic acids (more than 40%) have been classified by the European Commission as feed materials that can be used in animal nutrition since 2013. A protective effect on the intestinal mucosa, as well as anti-inflammatory, adsorptive and antimicrobial properties, were recorded. Nutrient absorption, nutritional status and the immune response in chickens supplemented with HSs were significantly improved. HSs have the ability to enhance protein digestion as well as the utilization of calcium and trace elements. They are known to improve feed digestibility as a result of maintaining an optimal pH in the gut, leading to lower levels of nitrogen excretion and less odor in the husbandry environment. HSs not only increase digestibility and result in greater utilization of the feed ration but also improve the overall quality of the meat produced. They increase the protein content and reduce the fat content in breast muscles. They also contribute to improving the sensory characteristics of the meat produced. Their antioxidant properties improve the oxidative stability of meat during storage. The influence of HSs on fatty acid composition may be one of the reasons that meat has a more beneficial effect on the health of consumers.