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The chemical composition and culinary meat tenderness belong to the most important characteristics determining meat quality and value. The aim of this work was to compare texture profiles and shear force of pork loin (m. longissimus dorsi) and of pork ham (m. semimembranosus) from fatteners of Polish Landrace (PL), Polish Large White (PLW), Duroc, Pietrain and Puławska pig breeds slaughtered at 60, 90, 120, 150, 180 and 210 d of breeding. Meat was roasted at 180°C to inner temperature of 78°C. The intramuscular fat (IMF) content in loin was growing with fattener age (from 1.17% at 60 d to 1.84% at 180 d of life). Between breeds IMF ranged from 0.82% in PLW to 2.29% in Puławska breed. The shear force for loin muscle ranged from 3.42 kG/cm2 at 60 d to 6.54 kG/cm2 at 210 d of life while for and ham muscle 4.4 kG/cm2 at 60 d to 6.78 kG/cm2 at 210 d of life. The hardness (TPA) ranged from 72.29 N at 90 d of life to 109.46 N at 210 d of life. The shear force of loin and ham meat was increasing with age of fatteners and some texture parameters – hardness and chewiness. Nevertheless it seems that the age of 150 days is the time when meat of fatteners is characterized by the highest technological properties. However, the final decision regarding slaughter age should be made taking into account the technological destination of the carcasses. No significant interactions between the animal breed and their age were found for the parameters analysed.

Species identification of the components of various duck breeds has revealed that the lowest identifiable number of components depends on the breed. The results (shown on the agarose gel) of a species-specific PCR reaction for Rouen ducks were less intense than the results for the same amount of components from other popular duck breeds, suggesting differences in the Rouen duck genome. Therefore, the present study aimed to identify part of the Rouen duck’s gene sequences and to develop two new primer pairs. The first pair enables breed-independent identification of duck DNA, and the second distinguishes Rouen ducks from Chinese and Indian Runner ducks. The sequencing reaction yielded sequences of 1386 bp in length, and the identified sequence differs by around 7% from the sequences of Chinese duck species. The detected sequence contributes to improving species identification methods for duck DNA. On its basis, two primers for the identification of duck DNA were designed. The first allows for DNA amplification with the same sensitivity regardless of duck breed. The second primer’s pair is breed specific, and it distinguishes Rouen ducks from Chinese and Indian Runner ducks. Both methods are very sensitive (0.05%).

This study developed a method to identify the species of duck and goose DNA extracted from various matrices. The research material included meat, down, whole feathers, and blood. The analysis was performed with real-time PCR using minor groove binder probes and primers that bind to cytochrome b (duck) and 12S ribosomal RNA (goose) sequences. For all matrices, the reactions were species-specific. Cross-reactions either did not occur or occurred after 36 cycles, corresponding to an amplification for the species content of 10− 5 %, i.e., several times below the limit of detection (LOD = 0.01%) and limit of quantification (LOQ = 0.1%). The standard curves obtained by consecutive dilutions were linear (R2 > 0.99), the slopes ranged from 3.2 to − 3.6, and the retardation factors were 23–26. The amplitude threshold analysis demonstrated that significant differences between successive matrices make it impossible to select one reference material to produce a standard curve effective for analyzing each type of matrix. A comparison between the reference material and the test material reveals that the accuracy of the developed method (the match between the actual and the measured value) is above 78%. Validation methods indicate that this method can be used to identify duck and goose DNA in the analyzed matrices.

European Union regulations (e.g. Commission Regulation (EU) No 56/2013) set restrictions on the use of poultry meals in animal nutrition, which requires the species composition of manufactured feeds to be constantly monitored. The aim of this study is to develop a method for qualitative analysis of poultry meals, enabling the four main poultry species (chicken, turkey, duck, goose) to be detected using one pair of primers, and a method for quantitative determination of chicken meals in poultry meals. The qualitative identification method was developed using PCR technology, whereas qPCR and TaqMan probes were used for quantitative identification. The study was performed with samples of feed mixture containing poultry and chicken meal. The limit of determination was 0.08% and 0.02% for qualitative and quantitative identification, respectively. The results of quantitative determinations obtained for independent DNA isolations from the same samples are repeatable (RSDcT ≤0.46%). The determined concentrations are accurate (Dc ≤11.23% for c ≥0.06). The identification of target sequences in both tests is good enough for commercial applications.

Chicken is a common protein source in pet foods and is concurrently listed among food allergens. Commercial over-the-counter (OTC) diets with an alternative animal protein source are considered suitable for dietary elimination trials by pet owners. The potential presence of undeclared chicken-derived ingredients in these diets can compromise the outcome of the trial during the diagnosis of adverse food reactions. The aim of this study was to selectively verify the absence or presence of chicken DNA in 10 OTC dry canine foods, using qualitative and quantitative approaches. The method of identification of chicken-derived protein was elaborated with the polymerase chain reaction (PCR) technology, whereas quantitative real-time PCR was used for the quantitative assessment. In most of the analysed samples, the chicken DNA was detectable; however, the quantified amounts were predominantly low, although differences between batches were observed.

The effect of supplements of medium-chain fatty acids (MCFA) and/or probiotic (Enterococcus faecium) on piglet performance, intestine structure, and microbiology was estimated on 271 piglets (24 litters) of Polish Landrace. Piglets were allocated to three groups with eight litters in each, kept in group pens, and fed the standard feed mixture (negative control, group I). The same mixture supplemented with 0.3% of caprylic (octanoic—C8) or 0.3% of capric (decanoic—C10) acids was given to groups II and III, respectively. In each group, half the animals received Cylactin® added in the amount of 0.35×109 CFU per kg feed. The feed and water were available ad libitum. Piglets were weaned at 28 days of life. At 60 days of life, 6 piglets from each subgroup were slaughtered and their intestines were investigated. Digesta from digestive tract was removed and the length and weight of particular parts of intestines were measured. The structure of the ileum mucosal epithelium was examined. Acidity of digesta and short-chain fatty acid (SCFA) content of chyme from jejunum and cecum were analyzed. Escherichia coli and Clostridium perfringens counts in these parts of intestines were also estimated. Capric acid improved piglet body weight gain after the 28th day of life. Probiotic lowered the weight gain from 28th to 56th day but increased it later. There was no difference in feed intake, and feed utilization was improved only by probiotic in the last period of the experiment. Probiotic increased pH in the small intestine and colon and significantly increased the amount of acetic acid in cecum. Capric acid reduced the total length of the intestines. Probiotic had no effect on intestines’ mass and length, but it increased villi width and crypt depth in the epithelium of small intestine. MCFA had no effect on these qualities. Both supplements had strong antibacterial activity: acids against E. coli and probiotic against C. perfringens.