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The effect of long‐term under‐ and overfeeding on the expression of six major milk proteins' genes in the mammary tissue of goats
Author(s) -
Tsiplakou E.,
Flemetakis E.,
Kouri E.D.,
Karalias G.,
Sotirakoglou K.,
Zervas G.
Publication year - 2016
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/jpn.12394
Subject(s) - lactose , casein , biology , gene , lactation , mammary gland , gene expression , messenger rna , endocrinology , medicine , andrology , food science , biochemistry , genetics , cancer , breast cancer , pregnancy
Summary Milk protein synthesis in the mammary gland involves expression of six major milk proteins' genes whose nutritional regulation remains poorly defined. In this study, the effect of long‐term under‐ and overfeeding on the expression of as1‐casein: CSN 1S1, as2‐casein: CSN 1S2, β ‐casein: CSN 2, κ ‐casein: CSN 3, α ‐lactalbumin: LALBA and β ‐lactoglobulin: BLG gene in goat mammary tissue ( MT ) was examined. Twenty‐four lactating dairy goat, at 90–98 days in milk, were divided into three homogenous subgroups and fed the same ration, for 60 days, in quantities which met 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements. The results showed a significant decrease in mRNA of CSN 1S2, CSN 2, CSN 3 and LALBA genes in the MT of underfed goats compared with the overfed and on the CSN 1S1 and BLG gene expressions in the MT of underfed goats compared with the respective control and overfed. CSN 2 was the most abundant transcript in goat MT relative to the other milk proteins' genes. Significantly positive correlations were observed between the mRNA levels of caseins' and BLG genes with the milk yield. Moreover, a significant correlation was found between the mRNA levels of CSN 1S2 with the milk protein, lactose content and lactose yield and also between the LALBA gene expression with the lactose content and lactose yield respectively. In conclusion, the feeding level and consequently the nutrients availability affected the milk lactose content, protein and lactose yield as well as the milk volume by altering the CSN 1S1, CSN 1S2, CSN 2, CSN 3, LALBA and BLG gene expression involved in their metabolic pathways.