Beata Kuczyńska

Alternative for modifying the fatty acid composition and decreasing the cholesterol level in the milk of cows

Abstract The goal of the experiment that was carried out on Friesian cows was to study an opportunity of decreasing the cholesterol and increasing the level of polyunsaturated fatty acids in the milk fat leaving the milk yield unchanged. The investigations were conducted in year 1999 and repeated again in 2000. Cows were randomly assigned into two groups: control (16 cows) and experimental (19 cows), and fed a total mixed ration (TMR) ad libitum. During the 7 weeks of the investigations the ration of the experimental animals was supplemented with 21 g linseed and 21 g/day trace element–mineral mixture containing Mg, Fe, Cu, Co, Mn, Zn, Se, Cr and CaCO3. The cholesterol level in the milk of the experimental cows appeared to be 32% lower than in controls. The additives applied affected favourably also the fatty acids’ composition. The proportion of unsaturated fatty acids in the milk of the experimental cows was found to be 15% higher and that of saturated fatty acids 8% lower in comparison with the control animals. The most pronounced changes occurred in the CLA and linolenic acid content of the milk fat. The supplement had a small if any effect on the milk production and on the milk fat, protein and lactose content of the milk. The repeated experiment confirmed results of the first trial.

Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland

BACKGROUND The aim of the study was to investigate bioactive whey protein concentrations in cows milk collected in late pasture (LP) and early indoor feeding (EIF) season from conventional and organic farms in Poland. RESULTS Results showed that in the LP somatic cell count (SCC) was higher under organic farming conditions. However, percentages of protein and fat were higher under conventional farming conditions. In EIF, milk from conventional dairy farms had a higher percentage of fat and lactose and a lower concentration of protein and SCC in comparison to milk from organic farms. Organic milk in LP had higher concentrations of beneficial whey proteins than conventional milk, including β-lactoglobulin (β-Lg, 4.12 vs. 2.68 g L⁻¹), lactoferrin (Lf, 334.99 vs. 188.02 mg L⁻¹), and lysozyme (Lz, 15.68 vs. 12.56 µg L⁻¹). However, conventional milk in EIF had higher concentrations of bovine serum albumin (146.47 vs. 118.65 mg L⁻¹), Lf (49 vs. 185.27 mg L⁻¹), and Lz (16.63 vs. 13.22 µg L⁻¹). CONCLUSIONS The results show significant differences in the investigated parameters between organic milk and milk from conventional system during EIF and LP. Moreover, extending the pasture season during EIF in organic farms decreases concentration of bioactive compounds of milk.

The age of cows as a factor shaping the antioxidant level during a nutritional experiment with fish oil and linseed supplementation for increasing the antioxidant value of milk

BACKGROUND So far, in research studies, the age of cows has not been considered as a factor that may influence the changes in the content of milk ingredients with antioxidant properties modified by the feed supplementation. The aim of this study was to determine the influence of supplementation on the content of ingredients having antioxidant properties and to determine the influence of the age of cows taking part in the experiment on these changes. The experiment was conducted using 20 Polish Holstein Friesian cows, 10 primiparous and 10 multiparous. The combined supplementation of fish oil and linseed constituted the experimental factor. RESULTS The milk of primiparous cows after 21 days of supplementation was characterised by a higher content of C18:1 trans-11, C18:2 cis-9, trans-11, α-retinol, α-tocopherol and β-lactoglobulin compared to the milk of multiparous cows, in which a higher level of lactoferrin, C20:5 and β-carotene was recorded. In both groups an increase in the total antioxidant status was noted (a higher level in the milk of primiparous cows). CONCLUSIONS Modification of the diet of cows with fish oil and linseed significantly influenced antioxidant properties of their milk; however, the response of multiparous and primaparous cows was noticeably different to the supplement introduced.

Fat content and fatty acids profile of colostrum and milk of primitive Konik horses (Equus caballus gmelini Ant.) during six months of lactation

The effect of the stage of lactation, the number of foals and age of the mare on changes in the fat content and fatty acid composition of colostrum and milk of primitive Konik horses was investigated. Colostrum and milk samples from 12 lactating mares were collected at the beginning of lactation, on the days 1 and 2 after foaling and then, starting from the first month of lactation, at 4-week intervals up to the sixth month of lactation. Significant differences were observed in fat content as well as the composition of some analysed fatty acids between colostrum and milk of mares of the Konik breed. The number of foalings and the age of mares did not have a statistically significant effect on the fat content in milk and had only a slight effect on the fatty acid composition. Milk produced by mares of the Konik breed is characterized by a considerable content of polyene fatty acids with 18 carbon atoms, a low ratio of n-6 fatty acids to n-3 fatty acids as well as low, highly advantageous values of atherogenic and thrombogenic indices.

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.

Effect of different fat supplements on the antioxidant capacity of cow’s milk

Abstract. This study examined the effect of different fat supplements on the antioxidants of cow’s milk. Thirty five Polish Holstein Friesian cows at 180±20 day of lactation and averaging 17.71±2.26 kg/d of milk were divided into five equal groups. There were five treatments groups: 300 g/d of fish oil, 500 g/d of Opal linseed, 500 g/d of Szafir linseed, 150 g/d of fish oil + 250 g/d of Opal linseed, 150 g/d of fish oil + 250 g/d Szafir linseed. Milk samples were collected five times during the 21 day of supplementation period: at the 1st, 14th and 21th day of the experimental period, and also at the 14th and 21st day after the supplement withdrawal. Diet supplementation with the Szafir linseed improved the chemical composition and milk yield at the 21st day of experiment. The highest level of malondialdehyde was recorded in fish oil, Opal linseed, fish oil + Opal linseed, and fish oil + Szafir linseed groups, and the lowest in the Szafir linseed group. After the 21st day of supplementation the concentration of α-retinol was significantly increased in all groups by 23 to 183 %. The highest level of α-tocopherol was found in fish oil + Opal linseed group at the 21st day of supplementation. Total antioxidative status increased in all experimental groups; however, the highest peak was recorded in fish oil + Szafir linseed and Szafir linseed group. The experiment confirmed that manipulation in cows’ diet may improve antioxidative capacity of milk.

Effect of supplementation of cows diet with linseed and fish oil and different variants of β-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 β-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 β-LG (β-LGAA, β-LGBB, β-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 β-LGAA was associated with lower levels of atherogenic and thrombogenic indices and higher concentration of C22:5 n-6, phospholipids and β-carotene. β-LGBB favours a higher content of C18:1trans-11, C18:2cis-9 trans-11 and lactoferrin. β-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 β-LG phenotype on the fatty acid composition and antioxidant capacity of milk is variable, which could partly be the result of a β-LG phenotype × diet interaction.

Influence of linseed variety on fatty acid profile in cow's milk

BACKGROUND The aim of this study was to examine the influence of linseed variety on the concentration of cows milk constituents, particularly fatty acids. The experiment was conducted on 30 Polish Holstein Friesian cows whose diet was supplemented with two varieties of crude linseed, Opal and Szafir. RESULTS After 21 days of linseed supplementation, the Szafir variety proved to be a better supplement than the Opal variety, particularly in relation to the concentration of saturated fatty acids, C20:5 (69.2% higher) and C22:6 (147.1% higher) and also because of improved chemical composition of the milk (19.7% higher fat, 2.9% higher protein and 39.9% higher casein content). CONCLUSION Linseed variety significantly influenced the lipid fraction level and the basic chemical composition of cows milk. Linseed variety should therefore be taken into consideration in subsequent experiments in addition to the quantity and physical form of linseed. The results showed that the use of a diet supplemented with linseed, especially the Szafir variety, was effective in reducing saturation, atherogenic and thrombogenic indices, yielding benefits for consumers by improving the nutritional quality of cows milk.

Relationships between physiological indicators in blood, and their yield, as well as chemical composition of milk obtained from organic dairy cows

BACKGROUND The occurrence of metabolic overload in cows maintained in organic herds is very likely, because organic production promotes feeding with high roughage diets and discourages supplementation with concentrates supplementation. It has the potential to negatively affect milk quality. The aim of this study was to determine the influence of physiological indicators in blood, reflecting the energy metabolism and liver status of dairy cows kept in organic herds, on the content of bioactive components in milk and the influence of lactation stage and feeding season on changes in milk components. RESULTS A significant positive correlation was found between β-hydroxybutyric acid and the daily milk yield of lactating cows. β-Hydroxybutyric acid was negatively correlated with lactation phase and polyunsaturated fatty acids as well as saturated fatty acids content in milk. A significant negative correlation was observed between average daily milk yield and alanine aminotransferase concentration in blood. A low level of production in organic farms had a positive impact on the content of conjugated linoleic acid (20% increase), vitamin A (21% increase) and vitamin E (11% increase). CONCLUSION The study has shown significant correlations between metabolic profiles and milk yields, as well as milk composition. In addition, there is evidence that the intensity of the production system significantly influences the metabolic profile and chemical composition of cows milk. It could even be concluded that the ecological system affects not only the quality of milk, but also the health of cows.

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 mares 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 mares 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.