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Effect of β ‐casein, κ ‐casein and β ‐lactoglobulin genotypes on concentration of milk protein variants
Author(s) -
Hallén E.,
Wedholm A.,
Andrén A.,
Lundén A.
Publication year - 2008
Publication title -
journal of animal breeding and genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 51
eISSN - 1439-0388
pISSN - 0931-2668
DOI - 10.1111/j.1439-0388.2007.00706.x
Subject(s) - casein , genotype , lactation , allele , beta lactoglobulin , milk protein , chemistry , biology , food science , zoology , whey protein , biochemistry , genetics , gene , pregnancy
Summary Individual mid‐lactation milk samples were collected from 116 cows of the Swedish Red and Swedish Holstein breeds with known genotypes of β ‐casein, κ ‐casein and β ‐lactoglobulin. Detailed milk protein composition and allele‐specific expression of β ‐casein, κ ‐casein and β ‐lactoglobulin proteins in milk were analysed using reversed‐phase high‐performance liquid chromatography. Aggregate β ‐/ κ ‐casein genotype was significantly associated with the κ ‐casein concentration in milk. The lowest κ ‐casein concentration was found in milk of cows with genotypes including κ ‐casein E (A 1 A 2 /AE, A 1 A 1 /AE) and also A 2 A 2 /AA milk, whereas highest levels were associated with genotypes including κ ‐casein B. Casein number was positively and concentration of β ‐lactoglobulin negatively associated with the β ‐lactoglobulin BB genotype. In heterozygote cows, β ‐casein A 1 and β ‐lactoglobulin A proteins were found at higher concentrations in milk compared with the protein variant encoded by the alternative allele at these loci, whereas κ ‐casein A and B variants were found at similar concentrations in heterozygote AB cows.