Proteinograma de leite de vacas com mastite subclínica em função do escore de células somáticas e de microrganismos isolados e identificados por microbiologia convencional
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2017-05-10
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Universidade Federal de Goiás
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Intramammary infections can be triggered by a large number of etiologic agents and may lead
to changes in the mammary gland parenchyma, composition of milk and reduction of milk
production. The aim of the present study was to evaluate the electrophoretic profile of cow
milk proteins by the analysis of microfluidic electrophoresis lab-on-a-chip and its alterations
in relation to milk samples with different SCC and the presence of pathogenic
microorganisms. A total of 101 milk samples were collected from cows from two dairy farms
located in the state of Goiás. Microbiological analyzes, somatic cell counts, centesimal
composition and microfluidic electrophoresis were performed. For the correlation test
between the protein profile and the SCC the samples were stratified into five groups of
somatic cells scores. The data were analyzed using descriptive statistics through the analysis
of variance and graphical representations. There was a significant increase in the value of the
protein component in relation to the SCS 1 and 3, 1 and 4 and 1 and 5. It was also possible to
observe statistical difference in the results of the Lactose component when comparing SCS 1
and 3 and SCS 3 and 4. The evaluation of the variable "Concentration" of milk proteins was
possible to observe differences in the concentration values of SCS. Statistical difference was
also observed for concentration of α-LA when compared SCS 1,2 and 3 to SCS 5; For IgG, SCS
samples 4 and 5 showed different concentrations of SCS samples 1,2 and 3; the LF protein
showed different results among samples from the SCS 1 and 5. The microorganisms identified
were Staphylococcus spp. Negative Coagulase, Arcanobacterium pyogenes, Streptococcus
spp., Staphylococcus aureus, Bacillus spp. and yeast. There is no statistical evidence that the
mean concentration of the proteins present in milk samples is different between any groups
of samples with different microorganisms evaluated. In the comparison between the
concentrations of each protein expressed in each group of samples, a statistical difference
was observed in the concentration of α-lactalbumin between samples from the yeast group
and samples without bacterial growth. It was concluded that whey proteins of high
abundance have their concentration decreased with the occurrence of mastitis; Defense
proteins such as Lactoferrin, Lactoperoxidase, IgG and IgM have their concentration increased
when comparing milk samples from cows with subclinical mastitis and milk samples from
healthy cows; Lactoferrin and IgG proteins are potential targets for identifying cows with
subclinical mastitis in milk samples and may be considered biomarkers. It was also concluded
that intramammary infections caused by the microorganisms identified in the present study
do not alter the concentration of whey proteins of lactating cows; Milk samples with high SCC
may present negative results for microbiological culture; The SCN showed higher frequency of
isolation in milk samples from lactating cows, revealing opportunistic and saprophytic
characteristics; And infection of the mammary gland caused by yeast causes a significant
increase of the α-lactalbumin protein.
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FREITAS, F. A. Proteinograma de leite de vacas com mastite subclínica em função do escore de células somáticas e de microrganismos isolados e identificados por microbiologia convencional. 2017. 74 f. Tese (Doutorado em Ciência Animal) - Universidade Federal de Goiás, Goiânia, 2017.