Comparison of Enzyme Activity in Order to Describe the Metabolic Profile of Dairy Cows during Early Lactation.

Enzymatic diagnostics have practical applications in diseases of the liver, heart, pancreas, muscles, blood, and neoplastic diseases. This study aimed to compare enzyme activity to describe dairy cows' metabolism during early lactation. Based on their general health symptoms, the cows were assigned to one of three groups: acidotic, healthy and ketotic. Samples of milk, blood and rumen fluid were collected at 12 ± 5 days postpartum. Ketotic cows were characterized by the highest malondialdehyde (MDA, 76.098 nM/mL), glutathione reductase (GluRed, 109.852 U/L), superoxide dismutase (SOD, 294.22 U/L) and gamma-glutamyltranspeptidase (GGTP, 71.175 U/L) activity. In comparing ketotic and acidotic cows, MDA, GluRed, SOD and GGTP activity were higher by a factor of almost: 1.85, 1.89, 0.79 and 2.50, respectively. Acidotic cows were characterized by the highest aspartate aminotransferase activity (AspAT, 125.914 U/L). In comparing acidotic and ketotic cows, AspAT activity was higher by a factor of almost 1.90. The use of enzymatic markers could limit the frequency of sampling for laboratory analyses and may result in a faster diagnosis of metabolic disorders. AspAT activity in blood serum seems to be a good indicator of acidosis; GGTP may participate in the pathogenesis of ketosis.

Reproductive Performance of Hycole Rabbit Does, Growth of Kits and Milk Chemical Composition during Nine Consecutive Lactations under Extensive Rhythm.

The goal of this study was to analyze the reproductive performance of does, growth of their kits, and chemical composition of their milk over nine consecutive parities in order to indicate the boundary of female reproductive profitability. The novelty of this study results from the combinations of three factors: extensive reproductive rhythm, commercial farming conditions, and a period of nine consecutive parities, showing the actual lifespan of a rabbit doe on commercial farms. The data was collected on 60 Hycole females kept at a commercial rabbit farm. Throughout the study, 32 does were excluded due to different reasons (e.g., excluded by means of selection-43.8% and mortalities-25.0%). The does were first inseminated at 28 weeks of age. Following artificial inseminations were conducted 14-15 days after each parturition. All kits were weaned at the age of 35 days. The following characteristics were analysed: body weight of rabbit does at artificial insemination, milk production per lactation, litter size, litter weight, average kit weight, and milk chemical composition. Rabbit does had a significant decrease in kindling rate between the eighth and the ninth parity (by 10.0 percentage points; p = 0.039). The litter size at weaning in the ninth parity was significantly lower to litters weaned at other analysed parities. The amount of milk produced per lactation was affected by the parity order (6.31-6.76 kg; p = 0.042). The litter weights on day 21 and 35 were the lowest at ninth parity. The content of total solids (TS), solids-not-fat, and fat was affected by the parity order on both analysed lactation days. The content of TS and fat in rabbit milk was characterized with a decreasing trend over the analysed period, on both lactation days. The results clearly indicate that rabbit does under extensive reproductive cycles characterize with a very good reproductive performance and can be successfully used for reproduction even up to the eighth parity. However, further research is needed if keeping them longer will not be profitable.

Using the Relationship between Concentrations of Selected Whey Proteins and BHBA to Characterize the Metabolism of Dairy Cows in Early Lactation.

A negative energy balance alters the concentration of various fractions of cows' milk. Therefore, by analyzing the concentration of individual proteins in milk, it is possible to indirectly monitor the health of the animal. The aim of the present study was to identify the relationship between the concentrations of blood ß-hydroxybutyric acid (BHBA) and whey proteins in milk as a marker for the diagnosis of metabolic diseases. The analysis included milk and blood samples from 95 Holstein-Friesian cows, which were divided into three groups that were differentiated in terms of serum BHBA levels 5-7 days post-calving: LBHBA, low level of BHBA: 0.200-0.500 mmol/L; NBHBA, optimal level of BHBA- control group: 0.500-1.200 mmol/L; HBHBA, high level of BHBA: >1.200 mmol/L. Concentrations of α-lactoalbumin in the milk after 7 days of lactation proceeded in accordance with the concentration of ß-hydroxybutyric acid, as follows: LBHBA > NBHBA > HBHBA. Concentrations of ß-lactoglobulin in milk after 14 days of lactation proceeded in accordance with the concentration of ß-hydroxybutyric acid, as follows: LBHBA < NBHBA < HBHBA. Therefore, it can be concluded that whey proteins can be used as non-invasive markers for diagnosing metabolic diseases. A high concentration of ß-lactoglobulin can be a marker for diagnosing ketosis. Conversely, elevated levels of α-lactalbumin may indicate the occurrence of a metabolic disorder, such as acidosis.

Metabolic profile according to the parity and stage of lactation of high-performance Holstein-Friesian cows.

OBJECTIVE: The aim of the study was to determine the effect of parity and the stage of lactation on the metabolic profile of cows based on the basic chemical milk components and the blood parameters. METHODS: The study material consisted of high-yielding Holstein-Friesian cows. In total, 473 cows were examined. According to the parity, cows were divided into four groups: primiparous (P), and multiparous in the second (M2), in the third (M3), and in subsequent lactations (M4). The feeding of cows was based on total mixed ration (TMR) ad libitum. Milk and blood samples were collected individually from each cow three times per standard lactation period. RESULTS: Greater exacerbation of changes in the dynamics of the blood plasma parameters examined was proved for multiparous cows. The highest value of ß-hydroxybutyrate acid (0.946 mmol/L) was found for multiparous cows from group M3 at the beginning of lactation. However, it was still in the normal range. The results showed aspartate aminotransferase, and gamma-glutamyl transferase (GGT) activities in dairy cows during lactation had significant variations taking in to account stage of lactation. The highest activity of GGT was found in the group of the oldest cows and measured from 26.36 U/L at the beginning of lactation to 48.75 U/L at the end of the lactation period. CONCLUSION: The time-related changes in the concentrations of the biochemical parameters described differ markedly among lactating cows, though the housing conditions on the research dairy farm are highly standardised. This indicates that the ability to cope with metabolic stress is mainly affected by the individual predispositions of cows and feed nutrient supply in different stage of lactation. Especially, the feed nutrient supply (in net energy for lactation), which was the best in TMR 1 in comparison TMR 3.

The Effect of Selected Factors on the Content of Fat-Soluble Vitamins and Macro-Elements in Raw Milk from Holstein-Friesian and Simmental Cows and Acid Curd Cheese (Tvarog).

The study was conducted to determine the content and retention of selected fat-soluble vitamins and minerals in curd cheese-tvarog made by a traditional method, taking into account the effect of the quality of the raw milk and the type of starter cultures used. The raw milk used to make the tvarog was obtained in various conditions, i.e., with and without the use of pasture forage (in a traditional and an intensive system), in two production seasons (spring/summer and autumn/winter), from two breeds raised in Poland (the Black-and-White variety of Polish Holstein-Friesian and Simmental). Two variants of starter cultures were used to make tvarog: Freeze-dried DVS starters (Flora Danica) and pure cultures of mesophilic lactic acid bacteria. The acidity and content of protein, fat, selected fat-soluble vitamins (A, D3, and E), and selected macro-elements (Ca and Mg) were determined in samples of bulk milk and cheese. Retention rates of individual nutrients from the milk to the cheese were calculated. A higher content of fat-soluble vitamins was found in milk obtained from Simmental cows kept in a traditional system in the spring/summer season, as well as in the tvarog produced from it. Vitamin retention rates from the raw material to the tvarog were above 90%. The mineral composition of the cheese was not associated with the quality of the milk used. Very low retention rates from milk to cheese were obtained for Ca and Mg (below 20%). Higher retention rates were obtained in the spring/summer season when culture variant 1 was used. However, the starter culture was not found to significantly influence the concentration or retention of vitamins in the experimental cheese.

The Effect of Staphylococcus spp., Streptococcus spp. and Enterobacteriaceae on the Development of Whey Protein Levels and Oxidative Stress Markers in Cows with Diagnosed Mastitis.

Mastitis is one of the most common diseases of high-yielding dairy cows, and over 90% of cases are caused by Streptococcus spp., Enterobacteriaceae, or Staphylococcus spp. Certain groups of proteins are very significant in terms of the cow's antioxidant, bacteriostatic, and germicidal properties: lysozyme (Lz), lactoferrin (Lf), and ß-lactoglobulin (BLG). This study aimed to determine the influence of Staphylococcus spp., Streptococcus spp., and Enterobacteriaceae on the secretion of bioactive whey proteins and oxidative stress markers. From the herd, 60 multiparous cows with diagnosed mastitis were selected. Samples were taken individually from each quarter and pooled, which gave 60 samples. Enterobacteriaceae did not affect the BLG synthesis, whereas lysozyme and lactoferrin responded to a high concentration of these bacterial strains. In the case of Staphylococcus spp. infection, the BLG level increased. These strains did not affect the levels of di-malonic aldehyde (MDA), lactoferrin, and lysozyme. In contrast, they were significantly influenced by Streptococcus spp. In summary, the levels of whey proteins and oxidative stress markers changed depending on the bacterial strain inducing inflammation. Lysozyme and lactoferrin may be markers of udder inflammation caused by Enterobacteriaceae and Streptococcus spp., whereas ß-lactoglobulin may prove useful in diagnosing Staphylococcus spp. induced mastitis.

Genes encoding equine ß-lactoglobulin (LGB1 and LGB2): Polymorphism, expression, and impact on milk composition.

ß-lactoglobulin is one of the most abundant milk whey proteins in many mammal species, including the domestic horse. The aim of this study was to screen for polymorphism in the equine LGB1 and LGB2 gene sequences (all exons, introns, and 5'-flanking region) and to assess potential relationship of particular genotypes with gene expression levels (measured in milk somatic cells) and milk composition traits (protein, fat, lactose, and total ß-lactoglobulin content). Direct DNA sequencing analysis was performed for twelve horse breeds: Polish Primitive Horse (PPH), Polish Coldblood Horse (PCH), Polish Warmblood Horse (PWH), Silesian, Hucul, Fjording, Haflinger, Shetland Pony, Welsh Pony, Arabian, Thoroughbred, and Percheron-and revealed the presence of 83 polymorphic sites (47 and 36 for LGB1 and LGB2 genes, respectively), including eight that were previously unknown. Association analysis of the selected polymorphisms, gene expression, and milk composition traits (conducted for the PPH, PCH, and PWH breeds) showed several statistically significant relationships; for example, the two linked LGB1 SNPs (rs1143515669 and rs1144647991) were associated with total milk protein content (p < 0.01). Our study also confirmed that horse breed had significant impact on both gene transcript levels (p < 0.01) and on milk LGB content (p < 0.05), whereas an influence of lactation period was seen only for gene relative mRNA abundances (p < 0.01).

Hycole Doe Milk Properties and Kit Growth.

The level of production and the physiochemical traits of rabbit milk affect the growth and the mortality of bunnies during lactation. The goal of the study was to analyze the effect of litter size and day of lactation on the quality traits of rabbit milk, milk production, and associative traits. The study was conducted on 32 Hycole does and their litters. The rabbit milk pH ranged from 6.61 to 7.46. The colostrum was characterized by the highest content of total solids (31.54 and 31.80 g kg-1) and fat content (15.73 and 15.9 g kg-1). The milk from the beginning of the lactation was characterized by the highest level of somatic cell count (SCC) (523.67 and 536.57 103 mL-1), which gradually decreased to reach the lowest level on days 17 and 21 of lactation. The daily milk production was greater for does nursing 10 kits per litter compared to those nursing eight kits per litter (p < 0.001). The peak of milk production occurred on day 17 postpartum. To conclude, the litter size has a clear effect on milk production as well as litter weight and litter weight gains. It is also important to note that the day of lactation affected the physiochemical traits of rabbit milk.

The relationship between plasma ß-hydroxybutyric acid and conjugated linoleic acid in milk as a biomarker for early diagnosis of ketosis in postpartum Polish Holstein-Friesian cows.

BACKGROUND: The aim of this study was to investigate the association between plasma ß-hydroxybutyric acid (BHBA) and conjugated linoleic acid in postpartum Polish Holstein-Friesian (PHF) cows. The experiment was carried out at an experimental dairy farm, where a herd of approximately 350 cows was kept. Samples were taken at six time points: between days 5-7, 8-14, 15-21, 22-28, 29-35, and 36-42, resulting in 510 samples of both milk and blood. The cows involved in the experiment were divided into two groups - ketotic and healthy - by taking into account general health symptoms, blood serum BHBA, and non-esterified fatty acids (NEFA) concentration at 5-7 days postpartum. RESULTS: In the first week of lactation, at 5-7 day in milk (DIM), the study showed a 53% lower level of C18:2 cis-9 trans-11 (CLA9) and an 80% lower level of C18:2 trans-10 cis-12 (CLA10) in cows with diagnosed ketosis compared to healthy cows. In the second week of lactation (8-14 DIM), a 34% lower level of CLA9 and a 54% lower level of CLA10 was found in the group of cows with BHBA levels > 1.2 mmol/L. Additionally, Pearson correlation analysis showed significant negative correlation between BHBA x CLA9 and BHBA x CLA10 in the first week of lactation: - 0.732and - 0.821, respectively. CONCLUSION: The study shows that that both CLA9 and CLA10 can be used as markers for the early diagnosis of elevated blood levels of BHBA in postpartum Polish Holstein-Friesian cows.

Palliative care in the emergency department as seen by providers and users: a qualitative study.

BACKGROUND: Much effort has been made to explore how patients with advanced chronic illness and their families experience care when they attend the Emergency Department, and many studies have investigated how healthcare professionals perceive Palliative Care provision in the Emergency Department. Various models exist, but nonetheless incorporating palliative care into the Emergency Department remains challenging. Considering both healthcare professionals' and users' perspective on problems encountered in delivering and receiving appropriate palliative care within this context may provide important insight into meaningful targets for improvements in quality of care. Accordingly, this study aims at exploring issues in delivering palliative care in the Emergency Department from the perspective of both providers and users, as part of a larger project on the development and implementation of a quality improvement program in Italian Emergency Departments. METHODS: A qualitative study involving focus group interviews with Emergency Department professionals and semi-structured interviews with patients with palliative care needs in the Emergency Department and their relatives was conducted. Both datasets were analyzed using Thematic Analysis. RESULTS: Twenty-one healthcare professionals, 6 patients and 5 relatives participated in this study. Five themes were identified: 1) shared priorities in Emergency Department among healthcare professionals and patients, 2) the information provided by healthcare professionals and that desired by relatives, 3) perception of environment and time, 4) limitations and barriers to the continuity of care, and 5) the contrasting interpretations of giving and receiving palliative care. CONCLUSIONS: This study provides insights into targets for changes in Italian Emergency Departments. Room for improvement relates to training for healthcare professionals on palliative care, the development of a shared care pathway for patients with palliative care needs, and the optimization of Emergency Department environment. These targets will be the basis for the development of a quality improvement program in Italian Emergency Departments.

5'-flanking variants of equine casein genes (CSN1S1, CSN1S2, CSN2, CSN3) and their relationship with gene expression and milk composition.

Genes encoding casein proteins are important candidates for milk composition traits in mammals. In the case of the domestic horse, our knowledge of casein genes is limited mainly to coding sequence variants. This study involved screening for polymorphism in 5'-flanking regions of four genes encoding equine caseins (CSN1S1, CSN1S2, CSN2, and CSN3) and making a preliminary assessment of their effect on the gene expression (on the mRNA and protein levels) and milk composition traits in selected horse breeds. Altogether, 23 polymorphisms (21 described previously SNPs and two novel InDels) were found in the studied sequences, the majority of which are common in various horse breeds. Statistical analysis revealed that some are putatively associated with gene expression or milk composition - for example, the c.-2047_-2048insAT polymorphism (CSN1S1) turns out to be related to the total milk protein content in Polish Primitive Horse (p < 0.05), whereas c.-2105C>G SNP (CSN2) is related to beta-casein relative mRNA level and milk lactose concentration in the Polish Coldblood Horse breed (p < 0.05). We have also found significant effects of horse breed and lactation time-point on gene expression and mare's milk composition. Our study indicates that the 5'-regulatory regions of genes encoding casein proteins are interesting targets for functional studies of their expression and the composition traits of mare's milk.

Relationship between the degree of antioxidant protection and the level of malondialdehyde in high-performance Polish Holstein-Friesian cows in peak of lactation.

Lipid peroxidation can be described as a process under which free radicals attack carbon double bonds of omega-3 and omega-6 fatty acids. Whereas the end products of this process are reactive aldehydes, such as malondialdehyde (MDA). Lipid peroxidation leads to adverse changes in the nutritional value of milk; therefore, higher degree of antioxidant protection (DAP) ensures higher stability of dairy products by effecting their high antioxidative potential. Therefore, the purpose of this study was to demonstrate the relationship between the DAP and the level of MDA in high-performance Polish Holstein-Friesian cows in peak of lactation. Sixty-three Polish Holstein-Friesian cows were selected to the experiment according to: parity (all in the 2nd lactation), phase of lactation (peak of lactation), cytological quality of milk (somatic cell count < 150 thousand/ml) and without diagnosed metabolic diseases. The data obtained were analyzed statistically by two-way ANOVA, and Tukey's post-hoc test. After analysis of performance the cows were divided into 3 groups (twenty one cows in each group) based on milk yield and MDA concentration. The study revealed a significant effect of the lactation performance of cows on MDA levels in milk (P ≤ 0.01). The highest concentration of MDA (61.137 nM/mL) was shown in milk of cows yielding between 50.00 and 55.80 kg/day. The highest concentration of fat was found in milk in which the MDA level ranged from 48 to 86 nM/mL. Whereas, the inverse relationship was demonstrated in case of protein concentration. The highest level of protein was found in cows with MDA levels in the range of 18-28 nM/mL (P ≤ 0.01). The lowest MDA level (in the range of 18-28 nM/mL) was associated with the highest concentration of vitamin E, ß-carotene, total antioxidant status (TAS) and DAP, measured in both milk and plasma. The obtained results show that lipid peroxidation leads to adverse changes in the nutritional value of milk; the highest DAP (7.89 x 10-3) was found in the cows with the lowest MDA concentration in milk.

Effect of Dairy Cow Crossbreeding on Selected Performance Traits and Quality of Milk in First Generation Crossbreds.

The main goal of crossbreeding Holstein-Friesian (HF) cows with bulls of other dairy or combined breeds is to improve their performance traits. Thus, the aim of this investigation was to compare the dairy performance traits of first generation crossbreds produced by crossbreeding Polish HF cows with bulls of other breeds (Norman, Norwegian Red, Danish Red, Brown Swiss, Montbeliarde, and Simmental). This was done by analyzing the fatty acid profile and technological quality of the milk from these first generation crossbreds. The investigation showed that crossbreeding greatly influenced the performance parameters and technological quality of the milk of the first generation crossbreds obtained from crossbreeding Polish HF cows with bulls of other dairy or combined breeds. The crossbreed cows characterized by the highest both quantity and quality of milk. Also, the best parameters of milk fat dispersion (that is, the highest values of these parameters) that are useful in the production of hard ripening cheeses and butter were found in the milk of crossbreed cows. Health beneficially, saturated fatty acids level in milk of crossbreeds was by 25.96% lower in crossbreds milk when compared to purebred cows. The most beneficial content of whey proteins was found in the milk of Polish HF and Norwegian Red crosses, where it was 19.04% higher than in pure breed Holsteins. F1 cows tend to express better functional traits than Holstein (PHF) cows. Effect of heterosis was larger and gave better results when there was a greater genetic distance between the animals used for crossbreeding. PRACTICAL APPLICATION: The effects of heterosis are opposite to the effects of inbreeding depression, and it extends the lifespan and use of animals as well as improves their fertility and health. The main goal of crossbreeding Holstein-Friesian cows with bulls of other dairy or combined breeds is to improve their performance traits. F1 cows tend to express better functional traits than Holstein (PHF) cows. Effect of heterosis was larger and gave better results when there was a greater genetic distance between the animals used for crossbreeding.

Degrees of Antioxidant Protection: A 2-Year Study of the Bioactive Properties of Organic Milk in Poland.

The aim of this study was to determine the nutritional value of organic milk in Poland, investigate the influence of diet on antioxidant capacity and degree of antioxidant protection (DAP), and to examine the effect of season on the bioactive properties of milk from organic farms. From 2014 to 2015, 820 milk samples were collected from 6 organic farms during indoor feeding season (IDS) and pasture feeding season (PS). Pasture feeding season + corn grain (PSCG) cows' daily ration during pasture feeding season was enriched with 4 kg a day of corn to improve dietary energy balance. Milk obtained during PS was found to have a higher fat content, slight but significantly lower protein content compared with milk from IDS. The study showed that the content of monounsaturated fatty acids (MUFA) in milk fat was strongly linked to the concentration of polyunsaturated fatty acids (PUFA) and, to a lesser extent, on the supply of MUFA. The IDS data (concentration of vitamin E, A, and ß-carotene) showed the lowest values compared with the PS and PSCG groups. Total antioxidant status (TAS) and DAP showed an increasing trend in organic milk. PSCG was associated with highest level of DAP (9% higher than PS and 79% higher than IDS) and TAS (37% higher than PS and 79% higher than IDS). The results obtained show that supplementation of the basic ration with corn grain improved both TAS and DAP. The higher DAP and TAS value is responsible for product stability, considering the risk factor related to levels of cholesterol-oxide intake in humans.

Variability of lysozyme and lactoferrin bioactive protein concentrations in equine milk in relation to LYZ and LTF gene polymorphisms and expression.

BACKGROUND: Equine milk is considered to be an interesting product for human nutrition, mainly owing to its low allergenicity and significant amounts of bioactive proteins, including lysozyme (LYZ) and lactoferrin (LTF). The present study assessed the effect of genetic factors on LYZ and LTF concentration variability in mare's milk. RESULTS: Significant effects of horse breed and lactation stage on milk LYZ and LTF contents were observed. The highest level of LTF and the lowest concentration of LYZ were recorded for the Polish Warmblood Horse breed. The highest amounts of both proteins were found for the earliest investigated time point of lactation (5th week). Altogether 13 (nine novel) polymorphisms were found in the 5'-flanking regions of both genes, but they showed no significant relationship with milk LYZ and LTF contents. Several associations were found between selected SNPs and the LYZ gene relative transcript level. CONCLUSION: While the present study indicated the existence of intra- and interbreed variability of LYZ and LTF contents in mare's milk, this variation is rather unrelated to the 5'-flanking variants of genes encoding both proteins. This study is a good introduction for broader investigations focused on the genetic background for variability of bioactive protein contents in mare's milk. © 2016 Society of Chemical Industry.

Metabolic profiles of cow's blood; a review.

The term 'metabolic profile' refers to the analysis of blood biochemical parameters that are useful to assess and prevent metabolic and nutritional disorders in dairy herds. In the higher standards of milk production, the priority in modern breeding is keeping dairy cows in high lactation and healthy. The proper analysis, as well as control. of their feeding and metabolic status is immensely important for the health condition of the herd. The disproportion between the genetically determined ability for milk production and the limitations in improving the energy value of the ration may be the cause of metabolic disorders. Negative energy balance has a major impact on the body's hormonal balance and organ functions and mostly appears during transition periods: from 3 to 2 weeks prepartum until 2-3 weeks postpartum. The term 'transition' is used to underscore the important physiological, metabolic and nutritional changes occurring in this time. The manner in which these changes occur and how they are diagnosed and detected are extremely important, as they are closely related to clinical and subclinical postpartum diseases, lactation and reproductive performance - factors that significantly shape the profitability of production. Therefore the priority for intensive milk production is prevention of metabolic diseases and other disorders. It is the intent of this review to synthesize and summarize the information currently available on metabolic status and physiological changes in the cow's body that occur during lactation, as well as to discuss the interpretation of the results, which will be a useful diagnostic tool in nutritional evaluations of the dairy herd. © 2016 Society of Chemical Industry.

Characterization of equine CSN1S2 variants considering genetics, transcriptomics, and proteomics.

Currently, research interest is increasing in horse milk composition and its effect on human health. Despite previously published studies describing the presence of intra- and interbreed variability of equine milk components, no investigations have focused on the genetic background of this variation. Among horse caseins and the genes encoding them, least is known about the structure and expression of the α-S2 casein gene, CSN1S2. Herein, based on direct sequencing of the equine CSN1S2 coding sequence, we describe the presence of 51-bp insertion-deletion (in/del) polymorphism, which significantly changes the protein sequence (lack or presence of 17-amino acid serine-rich peptide). Bioinformatic analysis revealed that the observed in/del polymorphism spanned exactly 2 exons; therefore, we hypothesized that we were observing different CSN1S2 splicing isoforms. However, further investigation indicated that the detected sequence variation was caused by a large (1.3-kb) deletion in the genomic DNA. We found that the polymorphic forms (A, longer; B, shorter; KP658381 and KP658382 GenBank records, respectively) were unevenly distributed among different horse breeds (the highest frequency of variant B was observed in coldblood horses and Haflingers). We propose that the analyzed polymorphism is associated with CSN1S2 expression level (the highest expression was recorded for individuals carrying the BB genotype), which was much more pronounced for milk CSN1S2 protein content than for relative transcript abundance (measured in milk somatic cells). Our results provide insight into the equine CSN1S2 structure and lay a foundation for further functional analyses regarding, for example, allergenicity or physiochemical properties of the observed CSN1S2 variants.

Effect of supplementation of cows diet with linseed and fish oil and different variants of ß-lactoglobulin on fatty acid composition and antioxidant capacity of milk.

BACKGROUND: The aim of this study was to determine the influence of polymorphic variants of ß-lactoglobulin in cows supplemented with linseed and fish oil on the fatty acid composition and antioxidant capacity of milk. From the herd of 320 Polish Holstein Friesian cows three groups of cows were selected according to the variants of ß-LG (ß-LGAA, ß-LGBB, ß-LGAB). During the first 7 days (the initial period) all the cows were fed the same total mixed ration (TMR) diet. From day 8 to 28,150 g fish oil and 250 g linseed (FOL) was added to the TMR diet of each cow. RESULTS: The results showed that the diet supplemented with FOL was effective in reducing atherogenic and thrombogenic indices. Introducing supplementation improved the antioxidant capacity: higher concentration of C18:2cis-9 trans-11, C20:5 n-3, C22:6 n-3, bioactive whey proteins and vitamin soluble in fat has been recorded. The results showed that ß-LGAA was associated with lower levels of atherogenic and thrombogenic indices and higher concentration of C22:5 n-6, phospholipids and ß-carotene. ß-LGBB favours a higher content of C18:1trans-11, C18:2cis-9 trans-11 and lactoferrin. ß-LGAB was associated with higher concentrations of C20:5 n-3, Lysozyme, α-retinol, α-tocopherol and total antioxidant status. CONCLUSION: Modification of the diet of cows with fish oil and linseed significantly influenced fatty acid composition and antioxidant properties of milk. The effect of ß-LG phenotype on the fatty acid composition and antioxidant capacity of milk is variable, which could partly be the result of a ß-LG phenotype × diet interaction.

Screening for the Most Suitable Reference Genes for Gene Expression Studies in Equine Milk Somatic Cells.

Apart from the well-known role of somatic cell count as a parameter reflecting the inflammatory status of the mammary gland, the composition of cells isolated from milk is considered as a valuable material for gene expression studies in mammals. Due to its unique composition, in recent years an increasing interest in mare's milk consumption has been observed. Thus, investigating the genetic background of horse's milk variability presents and interesting study model. Relying on 39 milk samples collected from mares representing three breeds (Polish Primitive Horse, Polish Cold-blooded Horse, Polish Warmblood Horse) we aimed to investigate the utility of equine milk somatic cells as a source of mRNA and to screen the best reference genes for RT-qPCR using geNorm and NormFinder algorithms. The results showed that despite relatively low somatic cell counts in mare's milk, the amount and the quality of the extracted RNA are sufficient for gene expression studies. The analysis of the utility of 7 potential reference genes for RT-qPCR experiments for the normalization of equine milk somatic cells revealed some differences between the outcomes of the applied algorithms, although in both cases the KRT8 and TOP2B genes were pointed as the most stable. Analysis by geNorm showed that the combination of 4 reference genes (ACTB, GAPDH, TOP2B and KRT8) is required for apropriate RT-qPCR experiments normalization, whereas NormFinder algorithm pointed the combination of KRT8 and RPS9 genes as the most suitable. The trial study of the relative transcript abundance of the beta-casein gene with the use of various types and numbers of internal control genes confirmed once again that the selection of proper reference gene combinations is crucial for the final results of each real-time PCR experiment.

The etiology of oxidative stress in the various species of animals, a review.

Oxidative stress is the consequence of an imbalance of pro-oxidants and antioxidants leading to cell damage and tissue injury. The exhaustion of antioxidant systems is one of the reasons for the occurrence of oxidative stress, which results in avalanche production of reactive oxygen species (ROS) or free radicals. High oxidative stress is common in organs and tissues with high metabolic and energy demands, including skeletal and heart muscle, liver and blood cells. Stress arises in animals in response to unavoidable or adverse environmental conditions. In the external environment, which affects the body of the cow, there are four main groups of stressors: physical, chemical, biological and psychological. Physical stressors include fluctuations in ambient temperature as well as mechanical injuries. High ambient temperature is one of the factors affecting the productivity of cows. Biological stressors are conditioned by errors and irregularities in habits. Both of these phenomena have an adverse impact on both the resistance of animals and fertility and are the etiological agent of oxidative stress. Various mechanisms may be responsible for metal-induced oxidative stress: direct or indirect generation of ROS, depletion of glutathione and inhibition of antioxidant enzymes are well known for all redox-active and redox-inactive metals.