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Pathology of Experimentally Induced Mastitis and Studies on the Immune Responses against Escherichia Coli Biofilm Vaccine against Mastitis in Rabbits

KrishiKosh

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Title Pathology of Experimentally Induced Mastitis and Studies on the Immune Responses against Escherichia Coli Biofilm Vaccine against Mastitis in Rabbits
 
Creator Ravikumar, P.
 
Contributor Suguna Rao
Yathiraj, S.
Satyanarayana, M.L.
Byregowda, S.M.
Rajeshwari, Y. B.
Shrikrishna Isloor
 
Subject ---
 
Description Ph.D. Thesis
An attempt was made to understand the pathology of E.coli mastitis by inducing
mastitis experimentally in rabbits using E.coli strains isolated from bovine mastitis cases
and to compare the efficacy of a biofilm vaccine with that of a free cell vaccine in
reducing the intramammary infections in rabbits. In the first phase of the experiment, six
rabbits each were infected with E.coli strains O9(36) and O147 to establish the pathology
induced mastitis. In the second phase, 12 rabbits each were vaccinated with the free cell
and biofilm vaccines against E.coli O9(36) and were later challenged with either a
homologous or heterologous strain of E.coli. Both O9(36) and O147 strains induced acute
clinical mastitis in the rabbits by 24 hours post inoculation characterized by rise in body
temperature, steep rise in SCC and viable counts of E.coli in milk and inflammation of
the mammary glands. Histologically, the infected mammary glands revealed degeneration
and necrosis of the lining epithelial cells, presence of large number of heterophils in the
lumina of acini and septa, severe destruction of the acini, and presence of E.coli
organisms in clumps within the acini, interlobular septa and the perivascular areas. The
lesions were more intense at 48 hours PI and reduced thereafter in magnitude and
severity. Both FC and BF vaccinated rabbits showed reduced clinical signs of mastitis
upon challenge but the clinical signs were very mild in the biofilm immunized rabbits.
The SCC values and viable counts of E.coli in milk of the challenged rabbits showed an
increase after challenge but the values were significantly lesser compared to that of the
positive controls. The reduction in the mean SCC and viable counts of E.coli values in
the BF vaccinated rabbits was much higher compared to that of the FC vaccinated
rabbits. The severity of the microscopical changes and ultrastructural changes observed in
the mammary glands of both FC and BF vaccinated rabbits challenged with E.coli were
lesser in comparison with those of the positive controls and the severity of lesions was
lesser in the BF vaccinated group than the FC vaccinated group of animals. The
vaccinated rabbits showed considerably higher number of both CD4 and CD8 cells
compared to the control animals on all the occasions. Among the free cell vaccinated
group, the homologous challenged rabbit showed most number of CD4 cells at 48 hours
post infection while the homologous challenged biofilm vaccinated rabbits showed
profoundly increased number of both CD4 and CD8 cells on 14th and 21st days post
challenge. The seromonitoring of the vaccinated rabbits by an indirect ELISA revealed
that the biofilm vaccinated rabbits showed increased IgG titers after vaccination
indicative of better immune responses. The titers were significantly higher in the biofilm
vaccinated rabbits than the free cell vaccinated rabbits particularly on day14 & day 21
post challenge.
 
Date 2016-08-02T13:46:11Z
2016-08-02T13:46:11Z
2010-06-04
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/70548
 
Language en
 
Format application/pdf
 
Publisher Karnataka Veterinary, Animal and Fisheries Sciences University, Bidar