The research carried out on meat from 45 ram lambs of the Polish merino breed allowed to determine the effect of meat aging and muscle type on physicochemical characteristics and oxidative stability of lipids. Analysis of physicochemical traits (pH, meat color, expressed juice, cooking loss, shear force, moisture, protein, fat and total collagen content) was performed on fresh and meat aged for 14 d in the longissimus lumborum (LL) and gluteus medius (GM) muscles. The meat aging determined all physicochemical characteristics except protein and fat content. More changes in pH and meat color parameters were defined in the GM muscle compared to the LL muscle. The increase in the tenderness of meat expressed as a reduction (P < 0.05) of shear force values was observed in both muscles aged for 14 d. A lower value (P < 0.05) of the shear force, despite the higher content of collagen, was determined in the GM muscle compared to LL. The investigated muscles differed in the degree of lipid peroxidation expressed as thiobarbituric acid-reactive substances (TBARS) in both fresh and aged meat. The TBARS value was lower (P < 0.05) in the LL muscle than in GM. In the longissimus lumborum muscle, the significantly lower content of polyunsaturated fatty acids (PUFAs) and PUFA n-6 has been recorded. The oxidation stability was not influenced by the meat aging.

Wet brewers grain (WBG) is successfully used in animal nutrition, and due to its high fiber content, especially in ruminants. The low cost of this fodder also has an impact on the economic of production. The aim of this study was to determine the effects of adding WBG to lamb fodder on the body weight gain, slaughter value and meat quality. The experiment was conducted on 40 male lambs of Polish Lowland sheep. The lambs were divided into two feeding groups, the control and the experimental (20 heads in each group), and fattened to their slaughter weight of 40 kg (± 2.5 kg). In the experimental group 35 % WBG was added to the feed. Lambs fed with WBG were characterized by higher daily weight gains (P ≤ 0.01) and reached their slaughter body weight significantly faster (P ≤ 0.01). Furthermore, the carcasses of the WBG group showed better hind leg conformation (P ≤ 0.01) and a higher content of prime cuts (P ≤ 0.05). The meat of lambs fed on WBG also had a lighter color and a lower intramuscular fat content. Additionally, the meat of this group was also characterized by higher PUFA (P ≤ 0.01) and C18 : 2 cis9, trans11 fatty acid (P ≤ 0.01) contents. The results obtained indicate that WBS could be successfully used in slaughter lamb production as a source of readily available, cheap fodder, especially when fattening takes place a short distance from a brewery.

An experiment was conducted to determine the chosen bioactive components and physico-chemical characteristics of lamb meat of different animal genotypes and the muscle types. The 22 ram lambs of Polish Merino (PM) and 22 crossbreeds of Polish Merino × Berrichone du Cher (PMB) were fattened to achieve their slaughter weight of 40 kg. After slaughter, the carcasses were kept at 4 ^∘C for 24 h. Then, the samples of longissimus lumborum (LL) and gluteus medius (GM) muscle were collected to analyse the physico-chemical traits; fatty acid profile; and concentrations of taurine, carnosine, L-carnitine. The GM muscle compared to LL had the higher value (P < 0.05) of L^* and a lower value (P < 0.05) of b^* and H^* both in PM and PMB lambs. The value of expressed juice was lower (P < 0.05) in both LL and GM muscles of PM lambs. A higher amount (P < 0.05) of collagen was found in LL muscle compared to GM both in PM and PMB lambs. The GM muscle of PM lambs showed higher (P < 0.05) conjugated linoleic acid (CLA) content, as well as higher total polyunsaturated acids (PUFAs), PUFA n-6, and PUFA n-3 (P < 0.05). The GM muscle was characterized by a higher (P < 0.05) content of taurine, while in the LL muscle there was a higher amount (P < 0.05) of carnosine. A larger amount (P < 0.05) of L-carnitine was found in GM muscle but only within PMB lambs. The obtained results showed a greater impact of the lamb's genotype on the physical characteristics of meat than on its chemical composition and the content of bioactive components. The muscle type had an effect on meat colour; collagen content; fatty acid profile; and amount of taurine, carnosine, and L-carnitine present.

Studies carried out so far have indicated the effect of the microbiome on the composition of ruminant products. Recent studies have shown that not only diet, but also genetic factors can affect the microbiological composition of the digestive system. The aim of the study was to determine the differences in the levels of selected bacterial phyla in terms of breed differences. Three sheep breeds, i.e., Olkuska, Romanov, and old-type Polish Merino, differing in their use (meat–wool, meat, prolificacy) and country of breed origin were included in the study. Sheep at the same age and of the same sex were kept for a period of 3 months in the same environmental conditions and fed the same feed in the same proportions. The study included real-time PCR (polymerase chain reaction) analysis of feces collected before the slaughter and measurements of body weight and chilled carcasses. The obtained results showed significant differences between the breeds in the levels of bacterial populations tested. There were also differences in body weight between the breeds during the first weight measurements, however, the final results did not show any differences—after three months of maintenance all of them reached similar body weights, despite differences in fecal microbiological composition. The study suggests that in addition to diet and environmental conditions, the microbiology can also be influenced by breed.

Wool characteristics vary depending on where on the body the wool is produced. Knowledge of this variation is important in order to separate the fleece into more homogenous parts. Similar parts from different animals can then be pooled to create batches of wool with similar characteristics. This will allow for better alpaca products with less variation. The aim of this study was to determine the variation in fiber diameter, medullation, and staple length across the body of alpacas from one herd. Wool samples were collected from 16 adult (3–5 years old) females: from the saddle (S), midside (MS), neck (N), and pieces (P). The mean fiber diameter (MFD) and medullation were measured using a projection microscope according to the IWTO-8-2011 standard. The fiber diameter of the pieces was greater (p < 0.05) than for the S, MS, and N areas. The highest medullation was found on the neck. The neck was also characterized by the shortest wool. The MFD for the fleece, excluding P, showed the strongest correlation (r = 0.927) with the MFD of MS. The study showed that due to the variation of fiber diameter, the incidence of medullation, and staple length, the wool from the pieces and the neck should be separated from the total fleece. The most appropriate site from where to collect a representative sample of wool from the fleece for testing purposes is the midside site of the animal.