BIOCHEMICAL CHARACTERIZATION OF FMD VIRUS AND ITS IMPACT ON METABOLIC PROFILE, OXIDATIVE STATUS AND OVARIAN ACTIVITY IN CATTLE
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Date
2011
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Birsa Agricultural University, Kanke, Ranchi, Jharkhand
Abstract
Foot and mouth disease virus (FMDV) is the first animal virus to be
identified in 1898 by Loeffler and Frosch. It is known as one of the most fearful viral
pathogens of animals since it is highly contagious among all species of cloven-hoofed
animals including cattle, sheep, goats and swine . It is caused by a small single-stranded,
positive- sense RNA virus of about 8500 nucleotides. It belongs to genus aphthovirus, family
Picornaviridae, The term aphthovirus is derived from the Greek word 'aphtha', which refers
to the vesicles found in the mouth and feet of affected animals. There are seven serotypes
of FMD virus reported globally. Firstly the serotypes O, A and C were discovered and later
on three additional serotypes found in Southern Africa and were named accordingly as
Southern African Territories types SAT1, SAT2, SAT3 and Asia-1.
Oxidative stress (OS) is an active field of research in Veterinary
medicine and has been implicated in numerous disease processes . Oxidative stress may
impair health in dairy cows both directly and indirectly. It a negative effect on animal health
and productivity as well as it has been implicated as a major initiator of tissue damage .
A limited number of conditions in ruminant medicine have been
investigated in regard to the effects of oxidative stress (Bras, 2010) but not on FMD infected
animals. With this in mind, it is the goal of this study to summarize the present knowledge of
oxidative stress in ruminant physiology and production during FMD. However, the
epidemiology and etiology of FMD have been extensively investigated (Yang et al., 1993)
but, a few published reports on haematological and biochemical parameters of cattle with
FMD are available (Elitok at el. 1999; Lubroth, 2002 and Gokce et al., 2004).
Keeping these in view, the work was designed to run in cattle with
the following objectives so that FMD in Indian origin is better understood and a more
effective treatment can be given.
i) Biochemical characterization of the FMD virus.
ii) To study the metabolic profile of FMD infected cattlea.
Haematological parameters
b. Biochemical parameters
iii) To study the impact of FMD on the oxidative status of infected cattle.
iv) To study the impact of FMD on the ovarian activity of infected cattle.
The present study was carried out in two groups of cross bred cattle.
Group I consisted of ten (10) crossbred cattle from Instructional Bovine farm, Ranchi
Veterinary College, that were clinically healthy and group II consisted of thirty (30)
crossbred cattle having clinical signs of FMD. Animals without characteristic lesions of
FMD were not considered for the study.
After estimation and statistical analysis by ANOVA , students’ t-test
and co-relation coefficient of various hematological and biochemical constituents, the
findings can be summarized as follows:
Hematology:
The concentration of hemoglobin in control and was found to be 9.966
± 0.344 % that had a decreasing trend to 9.220 ±0.337 %. The PCV was observed to be
27.899±0.603 % in the healthy animals while in the FMD affected animals it decreased to
26.464±0.588 % but the difference was non significant. The ESR value was recorded as 0 in
both the groups. The WBC count in control group was recorded as 5.775±0.320 X 103 which
slightly increased to 5.850±0.108 X103 in the test group while RBC count in group I was
5.588±0.220 X 106 which decreased significantly (P<0.05) to 5.065± 0.132 X 106 in group II.
The red blood indices ie MCH, MCV and MCHC in control animals were found to be
17.915±0.693 pg, 50.283±2.145 fl and 35.795±1.363% and in the test group animals the
values showed a non significant variation.
Clinical Biochemistry:
The concentration of protein in the healthy animals were recorded as
6.998 ± 0.288 gm/dl while in the FMD affected animals it decreased to 4.325±0.222 mg/dl
while the serum albumin concentration in group I was 4.325±0.222 gm/dl and in group II
was 3.230±0.251 gm/dl . Both total serum protein and albumin decreased highly significantly
(P<0.01). In the healthy animals the serum globulin concentration was recorded to be
2.637±0.296 gm/dl while in FMD affected animals was 2.516±0.174 gm/dl .The A:G ratio
was 1.777±0.201 and 1.334±0.163 in the control and FMD affected animal and both showed
a non-significant variation.The concentration of serum cholesterol, urea, BUN, uric acid and
calcium in group I was 116.792 ± 11.615, 15.637±0.9287, 7.128±0.413, 2.927±0.159 and
8.706±0.338 mg/dl respectively and in group II all decreased highly significant (P< 0.01) to
85.701±3.795, 12.075±0.430, 5.588 ± 0.125, 2.525±0.166 and 6.589±0.366 mg/dl
respectively. Serum creatinine, BUN:Creatinine ratio and blood glucose concentration was
estimated to be 1.297±0.267 mg/dl, 6.527 ± 1.212 and 45.769 ± 2.210 mg/dl respectively in
the healthy animals and all showed a decreasing trend in the diseased cows. The total
serum bilirubin, direct bilirubin (conjugated) and indirect bilirubin (non-conjugated) in the
healthy animals were 0.467±0.055, 0.329±0.015 and 0.138±0.023 mg/dl respectively. In the
FMD affected animals the concentrations changed slightly but indirect serum bilirubin
increased significantly (P< 0.05) to 0.271±0.089 mg/dl.
Enzymology:
The alanine transaminase (ALT) activity in control group was
observed to be 16.789±2.840 U/L and in test group it increased slightly while aspartate
transaminase (AST) activity was 78.032±3.187 U/L in the control group which increased
significantly(P< 0.05) to 95.105±5.582 U/L in the test group. Alkaline phosphatase (ALP)
activities in serum in group I and II were almost same in both the groups ie 39.258±2.195
U/L and 39.184±3.402U/L. Superoxidase dismutase (SOD) activity in hemosylate of group I
and II were 391.023±25.930 U/ml and 337.756±9.502 U/ml respectively. SOD activity
showed a significant (P< 0.05) decrease in group II. Glutathione peroxidase (GSH-Px) and
Glucose-6-phosphate dehydrogenase (G6PD) activity in hemoysate were observed to be
123.556±5.208 U/ mg Hg and 11.907±1.287 U/gm Hb respectively in group I which
decreased slightly in group II.
Vitamins:
The concentration of β- carotene in plasma was 1.075 ± 0.134 mg/dl
in control and in the test group it was almost same but ascorbic acid in healthy animals was
11.229±0.814 mg/dl and in FMD affected animals it decreased significantly (P<0.05) to
8.856±0.603 mg/dl .
Lipid peroxidation:
The amount of MDA produced was 1.904±0.132 nmol/gm Hb in the
healthy animals which increased slightly to 2.287±0.371 nmol/gm Hb in the FMD affected
animals.
Hormone activity:
The serum progesterone concentration during estrus phase in
control group was 0.77± 0.11 ng/ml and during luteal phase the was 7.310±1.546 ng/ml
which decreased slightly in the deseased animals both during estrus and luteal phase.
Molecular weight and mobilities of proteins:
The molecular weight of the FMD viral proteins I and II of trivalent A,
O and Asia 1 FMD vaccine were 101 and 62 K Da respectively as per known protein
molecular weight standard. Both in the control and FMD affected serum sample seven
distinct protein bands were observed and were from the top of the gel were as ϒ globulin, β
globulin, unidentified protein I, heptoglobin, albumin, α2 globulin and unidentified protein II in
the control serum sample. Their molecular weights were 150, 140, 120, 100, 60, 48, and 33
K Da respectively as calculated from the semi log graph. In the FMD affected sample, δ
globulin was undetectable but an extra band was noticed in the infected serum sample
which was identified as the FMD viral protein and their molecular weight was 40 K Da.
Correlation between the different parameters:
It was observed that among the blood haematological parameters, a
highly significant (P<0.01) positive correlation was observed between Hb and MCH and
MCHC, between PCV and MCV, between MCH and MCV and MCHC whereas a highly
negative significant (P<0.01) correlation was observed between RBC and MCV.
Among the serum protein fractions and liver enzymes, a positive
significant (P<0.05) correlation was observed between protein and albumin and A:G ratio,
between ALT and ALP but a significant (P<0.05) negative correlation was observed between
albumin and globulin and between globulin and A:G ratio. A highly positive significant
(P<0.01) correlation was observed between albumin and A:G ratio and a highly negative
significant (P<0.01) correlation was observed AST and ALT .
Among the serum biochemical variables, a positive significant
(P<0.05) correlation was observed between direct bilirubin and calcium and between
between indirect bilirubin and glucose but a negative significant (P<0.05) correlation was
observed between urea and glucose, between BUN and glucose and between direct
bilirubin and cholesterol. A highly positive significant (P<0.01) correlation was observed
between urea and BUN and between total bilirubin and indirect bilirubin and glucose .
Among the oxidative stress biomarkers, a positive significant
(P<0.05) correlation was observed between protein and albumin and SOD, between albumin
and ascorbic acid and between MDA and ascorbic acid but a negative significant (P<0.05)
correlation was observed between uric acid and ascorbic acid whereas between MDA and
SOD, there was a highly significant (P<0.01) negative correlation.
From the study it was concluded that:
Hematological and biochemical values were an efficient tool for
evaluation of physiological status and metabolic disorders which have a great relation to
health status of the animal. The animals affected with Foot and Mouth Disease showed an
alternation in the metabolic profile. There might be liver dysfunction as the liver enzyme
activities (liver function test) were increased indicating affected the metabolic profile.
Metabolic profile may also be affected also due to endocrinopathy, but to what extend it
occurs in cattle with FMD requires further study. Thus, biochemical and hematological
alternations may indicate the development of anemia, liver dysfunction and endocrinopathy.
The disturbed oxidative status of the animals affected with FMD
reflected that they were in oxidative stress condition. Most of the antioxidant biomarkers
showed a significant change in the infected animal. The depletion in the body’s antioxidant
resource have resulted from its action to counter balance the toxic effects of the oxidants
which is produced in increased amount during FMD confirming the occurrance of oxidative
stress during FMD. The present work summarizes the knowledge of oxidative stress in
ruminant physiology and production during FMD and highlighting the need for continued
research on oxidative stress in ruminant medicine since it is still in the early stage of
development.
The low serum progesterone concentration (non-significant) in FMD
affected cow is associated with sub functional ovarian activity as these animals may have no
corpora lutea which is the main source of serum progesterone. Oxidation stress as well as
less feed intake has a significant role in cessation of ovarian activity by affecting the growth
of graafian follicles and oocyte maturation. Thus, it can be concluded that during FMD, the
ovary is also involved.
The study has also provided information regarding the molecular
weights and mobilities of the FMD viral proteins in the trivalent FMD vaccine and FMD
affected serum sample. It was also seen that both the control and test serum sample
segregated into seven distinct bands but in the FMD affected serum sample the protein ϒ –
globulin was undetected but an additional FMD viral protein band was noticed.
Thus, the FMD affected animals should be treated symptomatically as
well as be given hepato stimulants. They should be provided with supplements rich in trace
minerals (eg Fe, Cu, Zn, Co etc.) and antioxidant vitamins (eg Vit A, Vit C, Vit E) which
would be beneficial for the antioxidant defence system. Again, further studies should be
made to set the levels at which it would be beneficial for the antioxidant defence system.
Finally, the present study may provide a better understanding of the
disease process and clinical pathology of Foot and mouth disease for a better line of
treatment.
Description
BIOCHEMICAL CHARACTERIZATION OF FMD VIRUS AND ITS IMPACT ON METABOLIC PROFILE, OXIDATIVE STATUS AND OVARIAN ACTIVITY IN CATTLE
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