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The effects of diet supplementation with yeast on the expression of selected immune system genes in the milk somatic cells of dairy goats

ustyna Jarczak
Polish Academy of Sciences Institute of Genetics and Animal Breeding, Jastrzębiec, 05-552 Magdalenka, Poland
Abstract :
The aim of the study was to evaluate the impact of diet supplementation with active yeast culture
Saccharomyces cerevisiae
) on the expression of selected immune system genes in goat milk somatic
cells (MSC) and on milk production traits. Eighteen dairy goats were divided by breed and parity
into two groups: control (n = 9) and supplemented (n = 9). Each group consisted of 5 Polish White
Improved (PWI) and 4 Polish Fawn Improved (PFI) goats. Four goats (2 PWI and 2 PFI) were
in their second lactation and five (3 WPI and 2 PFI) in more than second lactation. Beginning
from a week before expected kidding, supplemented does were fed 10g yeast/day/goat until 100
day post-partum, after which the dose was increased to 20g/day/goat. On day 7, 30, 80, 120 and
240 of lactation milk samples were collected and used to SC isolation, microbiological analysis
and to determine the physico-chemical composition of milk. Total RNA was isolated from SC and
expressions of β1-defensin, β2-defensin, bactenecin 7.5, bactenecin 5, hepcidin and lyzozyme genes
were measured with qRT-PCR using cyclophilin A (
) as a reference gene.
Supplementation with yeast did not affect milk yield and composition (P>0.05). Genes encoding β2-
defensin, bactenecin 7.5 and hepcidin were influenced by yeast diet supplementation resulting in their
increased expression in MSC (P
0.05) regardless of the amount of supplement. The environmental
bacteria did not affect the level of gene transcripts. However, the presence of β2
defensin, bactenecin
5 and 7.5, hepcidin and lysozyme transcripts in milk cells derived from pathogen-free udders proved
their constitutive expression. The expression of β1
defensin gene was not found indicating that it is
not constitutively expressed in milk cells and does not participate in the defense of the udder against
environmental bacteria. These findings support that β2-defensin, bactenecin 5, bactenecin 7.5 and
hepcidin may play a role in maintaining the health of the goat mammary gland.
Keywords :
ene expression / goat / milk SCC / yeast supplementation

Date Deposited : 02 Apr 2015 10:33

Last Modified : 02 Apr 2015 10:33

Official URL:

Volume 32, Number 1, - 2014

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