Abstract. The aim of the study was to determine the effect of selected meat packaging systems on certain quality attributes based on the example of breast muscles of broiler chickens. The research material consisted of 120 breast muscles of Ross 308 broiler chickens slaughtered at 36 days of age. The muscles were divided into four groups of 30 each, including one control group. The other three groups were packaged individually in three different packaging variants in accordance with the procedures used at meat processing plants: MAP, on a shrink-wrapped EPS tray and a vacuum. Analyses were performed of the following physical characteristics in the control samples (day 0, before packaging) and experimental samples (after seven days of storage): pH, WHC, EC, drip loss, composition of the mixture in the case of MAP packaging and colour measurement in the CIE L*a*b* system. The meat packed using various systems undergoes some changes during storage. The research confirmed significant differences in the quality characteristics of meat packed by different methods after seven days of storage. Vacuum-packed chicken breast muscles had a lighter colour and the highest electrical conductivity. These muscles also showed a higher drip loss, which may be of importance in processing.
Abstract. The aim of the study was to analyze various mating systems, mating dates, and the number of matings applied for farmed American mink in relation to resulting litter sizes. The observations were carried out on yearling females of two color varieties, Perl (P) and White Hedlund (WH), as well as yearling males belonging to four color varieties, namely P, WH, White Regal (WR) and Black Cross (BC). The color of the males was chosen so as to easily discern, which male sired which litter and what was the litter size resulting from the particular copulation date. The breeders were mated according to various mating schemes. The analysis revealed that if two matings were the case, most embryos conceived on the first date died.
Abstract. The aim of the study was to identify a potential occurrance of c.*1232G>A polymorphism in the 3'-UTR region of the myostatin gene (MSTN) in sheep of meat breeds: Pomeranian sheep, Suffolk and Berrichon du Cher. The populations of Suffolk and Berrichon du Cher breeds turned out to be monomorphic, whereas in the native Pomeranian sheep, the occurrence of polymorphism in the region of the MSTN gene was demonstrated. The Pomeranian sheep were characterized by a higher frequency of the mutated A allele (0.41), the frequency of genotypes AA and GA was 0.18 and 0.46 respectively. The effect of polymorphism c.*1232G>A on the body weight of ewes on the day of license has not been observed.
Abstract. Copy number variants (CNV) provide a valuable data resource for genetic analysis, but their detection is imprecise and subjected to a high number of false positives. Therefore, main goals of this study comprised investigating of the biological impact of genome sequence complexity on CNV formation and assessing whether quality of the reference genome resulted in a false positive CNV deletion calls. The comparisons of probability distributions of complexity measures underlying deletion breakpoints with complexity measures of permuted sequences, representing complexity of a randomised sequence, revealed highly significant differences between true and permuted sequences. A significantly larger number of unknown nucleotides was observed when comparing distributions of the numbers of unknown nucleotides in sequences flanking CNV deletion breakpoints with sequences flanking CNV duplication breakpoints. CNVs appear to be preferentially initiated in regions of low sequence complexity.
Abstract. The aim of the paper is to investigate the prevalence of metabolic diseases in selected dairy farms. The metabolic status of the Polish Holstein-Frisian dairy cows (PHF) was assessed using the fat to protein ratio (F/P ratio). The chemical quality of raw milk produced between 2014 and 2017 in ten herds located in eastern Poland (counties: Łosicki, Radzyński, Sokołowski and Ostrów Mazowiecka) was studied in the research. Based on 4838 daily observations, milk performance of 491 cows was assessed. The following indicators were determined: milk F/P ratio, milk daily yield and the content of protein, fat and dry matter. Several factors influenced basic milk composition and milk F/P ratio were tested. There were 4 lactation number groups (1 – first; 2 – second; 3 – third and fourth; 4– fifth to ninth lactations), 10 herd number (1–10), 4 stage of lactation groups (1 – 3, 4 – 6 , 7 – 10, 11 – 18 months), 4 classes of daily milk yield ( ≤ 15 kg, 15.1 – 25 kg, 25.1– 35 kg, >35 kg), 4 calving seasons (summer – JUN–AUG, autumn – SEP–NOV, winter – DEC–FEB, spring – MAR–MAY) and 4 milk F/P ratio groups ( ≤ 1 indicating rumen acidosis (SARA); 1.1 – 1.4 optimal; 1.41 – 1.7 indicating subclinical ketosis (SCK); >1.7 indicating clinical ketosis (KET). The average milk fat to protein ratio was 1.26, but it varied considerably within individual groups. The results also showed that 3313, i.e. 68.5%, of milk samples had the F/P ratio ranging from 1.1 to 1.4, indicating adequate nutrition with well-balanced daily rations. However, 8.2% of the observations indicated the occurrence of acidosis (SARA) in the cow population, 19.9% of the observations suggested the occurrence of subclinical ketosis (SCK) and 3.3% of milk samples were from cows affected with clinical ketosis (KET).