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Glucose metabolism and gene expression in the liver during transition period of Holstein and F1 Holstein-Gir cows

Juliana Guimarães Laguna ; Juliana Aparecida Lima ; Mariana Santos Cardoso ; Helton Mattana Saturnino ; Ronaldo Braga Reis ; Santuza Maria Ribeiro Teixeira
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The abundance of mRNA of genes involved in carbohydrate metabolism in the liver
quantified during transition period, between different genetic groups of cows in Brazil,
is not completely known. The aim of this search was to investigate hepatic gene
expression of the enzymes glucose-6-phosphatase (G6PC), phosphoenolpyruvate
carboxykinase citosolic (PEPCKc), methylmalonyl-CoA mutase (MUT), and the
transcription factors peroxisome proliferator-activated receptor alpha (PPARA) and
glucose transporter -2 (SLC2A2), and blood concentrations of glucose. Holsteins (Hn=6)
and F1 Holstein-Gir (F1-n=6) cows, under the same pre and postpartum
management conditions were used. Liver biopsies samples (to measure G6PC, PEPCKc,
MUT, PPARA and SLC2A2 gene expression) and blood samples (to measure glucose),
were taken at 15 days pre and at 6, 21, 36, 51 e 66 postpartum. The analyses of gene
expression were made by technique real-time polymerase chain reaction (RT-PCR) and
glucose concentrations were measured by commercial kit (katal®). The experimental
design was a completely randomized, and data were analyzed using PROC MIX
procedure of SAS. Tukey-Kramer test was used considering P ≤ 0.05. The expression of
genes G6PC, PEPCKc, PPARA and the SLC2A2 did not differ between genetic groups.
The G6PC gene declined 40 and 56.5% when comparing the pre calving gene
expression with 21 and 36 days in milking, respectively, and increased (P 36 days in milking. The results showed that mRNA level of the PEPCKc gene increased
after day 21 until day 51 in milking and decreased after that (P mRNA levels differed between the genetic groups (F1 > H; P tendency in reducing the abundance mRNA when comparing mRNA levels pre calving
and day 36 in milking (P = 0.066) and a significant increase after day 36 in milking. The
PPARA and SCL2A2 genes did not differ up to 66 days in milking. Glucose
concentration differed between genetic groups (F1 > H; P within genetic group up to 66 days in milking. It seems that there are differences in the
energy metabolism between the genetic groups analyzed, but it is need more searches.
Our data also suggest that F1 Holstein-Gir cows may be able to develop a more efficient
response due to an increased expression of the MUT gene, which encodes an enzyme
involved in the conversion of propionate to glucose.