the aim of this study was to track the changes in blood parameters of mid-lactation multiparous Polish Holstein-Friesian cows in response to a diet supplemented with a mixture of fish-soybean oils blend and tannin-containing lingonberry shrub (Vaccinium vitis idaea; VVi) extract. twelve lactating cows were randomly assigned to a crossover design of two treatments (6 cows per treatment) which consisted of a control diet containing no supplement (con) and con supplemented with a mixture of 99 g of VVI leaves extract and 660 g of blended fish-soybean oils (MIX) daily. The obtained results showed a significant increase in plasma glucose level, as well as C18:1t11 and n-3 fatty acids proportion. A significant decrease was also observed in insulin concentration, triglyceride and C18:0 proportion. Generally, the saturated fatty acid proportion decreased while the unsaturated fatty acid significantly increased with the MIX diet. In conclusion, using supplements of a mixture of VVI extract and fish-soybean oils blend modulated the unsaturated fatty acid proportion in blood, without affecting the dairy cows' blood parameters which were all within the normal ranges.

Fat content and fatty acid (FA) profile influence meat quality in pigs. These parameters are important for consumers due to their preferences for healthy, high quality meat. The aim of this study was searching for polymorphisms and transcript levels of two positional and functional candidate genes, FASN and INSIG2, encoding proteins which take part in lipid metabolism. The molecular findings were analyzed in relation to fatness traits. Pigs of four commercial breeds were included: Polish Landrace (PL), Polish Large White (PLW), Duroc and Pietrain. DNA sequencing, 5 0 RACE technique and real time PCR and association analysis were applied. In total, 20 polymorphisms in 5 0 -flanking, 5 0 UTR and 3 0 UTR regions of FASN (12 novel polymorphisms) and INSIG2 (seven novel ones and one known) genes were found. Association study with fatness traits (PL n = 225, PLW n = 179) revealed that four polymorphisms (c.-2908G[A, c.-2335C[T, c.*42_43in sCCCCA and c.*264A[G) of the FASN gene were associated with back fat thickness in PL and PLW. Since the polymorphisms were identified in regulatory sequences of the both genes also their transcript levels were studied in PLW (n = 23), PL (n = 22), Pietrain (n = 17) and Duroc (n = 23). The INSIG2 transcript level was positively correlated with monounsaturated FA contents in the longissimus thoracis et lumborum muscle. Several correlations were also found between three polymorphisms (c.*264A [G and c.-2335C[T in FASN, and c.-5527C[G in INSIG2) and the FA content. Our study showed that the FASN gene is a promising marker for subcutaneous fat tissue accumulation, while INSIG2 is a promising marker for FA composition.

ABSTRACT:Myostatin is considered to be one of the most powerful negative regulators of muscle growth. The lack of a functional myostatin (MSTN) or its mutation can result in uncommon musculature like "double-muscling" in Belgian Blue cattle. Recent studies on MSTN variability indicate its relationship with racing performance in dogs and racehorses. Considering the high homology of MSTN among the vertebrates, there are grounds to suppose that the same correlation will occur in pigeons. The aim of this study was to analyse MSTN variability in several pigeon breeds raised for different purposes. The PCR-RFLP method was used for genotyping the C → T silent substitution in exon 3 of the MSTN gene. A total of 376 domestic pigeons (Columba livia var. domestica) were genotyped. The differences in genotype frequencies (P < 0.01) and allele frequencies (P < 0.01), between the studied groups were observed. Minor allele (MSTN T ) frequency was the highest in the group of utility pigeons (0.291), which are characterised by abundant muscle mass and higher body mass-to-muscle mass ratio. Further studies should be performed in order to determine the impact of the SNP analysed in the present paper on the amount of functional myostatin in muscles.

BackgroundAdipose tissue is recognized as a highly active metabolic and endocrine organ. The hormones secreted by this tissue play an important role in many biochemical processes. It is known that dysfunction of adipocytes can cause insulin resistance, type 2 diabetes or hyperlipidemia. One of the important factors produced in fat tissue is resistin (Retn). It has been postulated that this hormone is involved in glucose homeostasis and insulin resistance. In the present study, the impact of five diet types (ad libitum normal, restricted, high-carbohydrate, high-fat and high-protein) on the Retn gene transcription and methylation profile was evaluated in rats of different ages.ResultsTranscript levels and methylation status of the Retn gene were studied in three tissues (muscle, subcutaneous and abdominal fat) in rats at 30, 60 and 120 days of age. We found an effect of tissue type on the Retn transcription in all diet types, as well as an effect of feeding type and age on the mRNA levels for high-fat and high-protein diets. The DNA methylation levels depended only on tissue type.ConclusionsThe obtained results demonstrate a tissue-specific expression pattern and a characteristic DNA methylation profile of the Retn gene in rats. Retn expression seems to be sensitive to nutritional changes, but only in the case of high-fat and high-protein diets. Moreover, an effect of age on Retn mRNA content was observed in these diets. Because no correlation between the transcript level and methylation status was found, we assumed that the transcription control of this gene by DNA methylation of the promoter seems to be unlikely.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0270-4) contains supplementary material, which is available to authorized users.

The genes encoding glucose transporter 4 (SLC2A4, GLUT4), insulin receptor (INSR) and glucocorticoid receptor (NR3C1) are considered regulators of energy metabolism that may influence fat content in skeletal muscle at different ages and breeds of pigs. In the study we performed analysis of expression of NR3C1, INSR and SLC2A4 genes in two skeletal muscle tissues: semimembranosus and longissimus dorsi muscle in gilts from three breeds of pigs that differed in intramuscular fat content: Duroc (DU), Pulawska (PUL) and Polish Large White (PLW) at 60, 90, 120, 150, 180 and 210 days after weaning. We also analyzed the expression of cortisol binding globulin (CBG) in the liver. Expression was analyzed with real time PCR (qPCR) using a relative quantification method. In blood, the concentration of cortisol, insulin and leptin were evaluated with radioimmunoassay. The concentration of metabolites (triglycerides and glucose) related to the changes of lipids content was also measured. We observed a significant relationship between the breed and the age of pigs and the expression of analyzed genes in muscle tissues (P &lt; 0.01 for all analyzed genes) as well as with two hormones (for insulin P = 0.001; for cortisol P &lt; 0.0001). Leptin level and metabolites in serum were not significant in the model (P &gt; 0.05). The expression of analyzed genes (SLC2A4, INSR and NR3C1 in muscles and CBG in liver) strongly correlates with intramuscular fat content in pigs and is associated with age and breed.