Background: The objective of this study was to determine the impact of fish oil and linseed (FOL) supplements on the protein fraction levels of milk from cows with different phenotypes of β-lactoglobulin.
Results: After 21 days of supplementation the study showed significantly higher concentrations of whey proteins, especially lysozyme (144% increase) and lactoferrin (45.5% increase), compared with milk from control cows (total mixed ration with no supplemented FOL). A reverse trend was demonstrated for casein, casein index and casein number (lower level). The most favourable change (higher level), in terms of lactoferrin, α-lactalbumin and bovine serum albumin contents in milk, was recorded in cows with the BB variant of β-lactoglobulin. The highest level of lysozyme was recorded in the milk of cows with the AB variant of β-lactoglobulin.
Conclusion: The combined supplementation of fish oil and linseed had a positive impact on whey proteins in cow's milk. In addition, the phenotype of β-lactoglobulin also played a role in milk protein composition. There is therefore a clear indication that nutritional experiments should take into account not only food supplements but also the genetic variants of β-lactoglobulin.
Keywords: casein; cow's milk; lactoferrin; lysozyme; whey protein; β-lactoglobulin phenotype.
© 2013 Society of Chemical Industry.