Veterinary World Vol.3(7): 323-325 RESEARCH Effect of induced Hypothyroidism on plasma cholesterol and bilirubin in Marwari Sheep

Hypothyroidism was induced in Marwari adult sheep (9 rams) by thiourea feeding (@ 50 mg/kg body weight). The blood samples were collected and analysed on 0 (control), 3rd, 5th and 7th day of thiourea feeding. The investigation was carried out to study the effects of induced hypothyroidism on plasma cholesterol and billirubin in Marwari sheep. Plasma cholesterol showed a non-significant (P > 0.05) effect of induced hypothyroidism however, it increased gradually with the subsequent phases of induced hypothyroidism. The analysis of variance (ANOVA) indicated a significant (P?0.01) increase in plasma bilirubin concentration during different phases of induced hypothyroidism in our study. Thus, Hypercholesterolemia and Hyperbilirubinemia are the salient clinical and biochemical features of induced hypothyroidism.


Introduction
Department of Animal Nutrition, CVAS, Bikaner.These animals were provided with standard ration and water Hypothyroidism is the commonest type of thyroid ad-libitum during the course of study.All experimental disorders encountered in the small ruminants.The rams were kept isolated from the rest of the sheep.clinical signs of hypothyroidism vary according to the They were housed in clean and well ventilated sheds.diverse effects of thyroid hormones on cell metabolism The experimental plan was divided into following (Sojka, 1995).Hypothyroidism may result in lowered phases: Control (Phase-I) and Induction of resistance to infection, increased susceptibility to experimental hypothyroidism ketosis, decreased susceptibility to hypomagnesaemia Control (Phase-I): Initially blood samples were and congenital goitre in the ruminants affecting both collected from the normal animals, referred as control their production and reproduction.Thiourea (organic animals.The samples of these animals were estimated goitrogen) is one of most widely used fertilizers in for plasma cholesterol and bilirubin.These parameters modern agriculture.It can be used as a good substance were treated as normal or control parameters.to induce and study hypothyroidism experimentally.
Induction of experimental hypothyroidism: Each The knowledge of blood metabolites in domestic control animal was further subjected to thiourea animals is of great clinical importance in assessment of feeding to observe the effects of induced their health, nutritional status, diagnosis and prognosis hypothyroidism during the course of study on of metabolic disorders as they are good indicators of mentioned parameters.physiological status of animals.Keeping in view, this To carry out the objectives of present study, study has been undertaken to observe the overall thiourea was used as a choice of drug toinduce effect of induced hypothyroidism on the status of hypothyroidism @ 50 mg/kg bodyweight.plasma metabolites i.e. cholesterol and bilirubin in This stage was further subdivided into three phases.Marwari sheep under agroclimatic conditions of 3rd day of Thiourea feeding (Phase-II) 5th day of Thiourea feeding (Phase-III) Western Rajasthan.7th day of Thiourea feeding (Phase-IV)

Materials and Methods
Blood samples (10 ml each) were obtained with Nine adult apparently healthy males (rams) of anticoagulant (heparin@ 30 IU/ml blood) by puncturing Marwari breed of sheep (above two years, weighing the jugular vein with least stress to animal under about 35-40 Kg) were included in our study.These aseptic conditions directly into the hot air oven sterile animals were procured from the project scheme in the tubes between 9.00 am to 9.30 am for control and 3rd, 5th and 7th days of thiourea feeding, respectively.the hepatic catabolism of cholesterol and its biliary Plasma for each sample was separated out on the excretion.Therefore, the decreased rate of lipid metabolism with diminished intestinal excretion of same day in the laboratory.For separation of plasma cholesterol, decreased conversion of lipids into bile the test tubes were centrifuged at 3000 rpm for 20 acids and other compounds and enhanced capacity for minutes and plasma was pipetted out in clear dry cholesterol transport in the blood in hypothyroidism plasma tubes.Only non-haemolysed plasma samples also results in hypercholesterolemia (Jubb et al., 1985).were used.After collection, plasma was stored at cholesterol concentration in the goitrous goats.In our study, the effect of thiourea feeding was Treatment of affected goats with thyroxine resulted in observed on the same animals which have been lowering of plasma cholesterol level as compared to referred as control animals.On 3rd, 5th and 7th day of p r e -t r e a m e n t va l u e w h i c h s u p p o r t e d t h e sampling during thiourea treatment, thiourea was hypocholesterolemic action of thyroxine reported by given just after the sampling.Kaneko (1999)

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Singh et al. (2002) reported elevated plasma lipid and -20 C in a deep freeze.
Bilirubin was estimated (mg%) by Malloy and Evelyn is helpful in clinical diagnosis of hypothyroidism.methodcitedbyVarley(1988),at540 nm or green filter.The combined effects of decreased peripheral Statistical analysis utilization to degradation and billiary excretion of fat The results were presented as Mean ± SE.The can be attributed to the hypercholesterolemia during mean values were determined according to the effect induced hypothyroidism in the present study.Thus, of induced hypothyroidism.The data was subjected to hypercholesterolemia can be considered as important analysis of variance (ANOVA)(Snedecor and Cochran, clinical as well as biochemical characteristic feature in 1967).The critical difference among various means case of hypothyroidism.were worked out by "Duncun's New Multiple Range hepatotoxicity.It is concluded that 13.Nordoy, A.et.al.(1976).Haemostatic and lipid abnormahypothyroidism affects hepatic and biliary functions lities in hypothyroidism.Scand.J. Haemat., 16:154 -160.which may lead to hyperbilirubinemia due to above 14.Rajgude, D.R.et.al.(2005).Biochemical alterations in mentioned reasons.the blood in experimental hypothyroidism in broilers.There is paucity of information regarding the Indian Vet.J., 82 : 1145 -1148.15.Ramakrishna,C.,et.al.(1994).Clinico-biochemical effects of induced hypothyroidism on blood/plasma observations on experimental hypothyroidism in goats.bilirubin concentration, particularly in sheep.Hence, it Indian Vet.J., 71: 1107 -1111.was not possible to compare with other reports in this 16.Singh, J.L.et.al.(2002).Assessment of therapy in respect.It warrants further research.goitrous goats through some cardiac function tests.Small Ruminant Research.44: 119 -124. subclinical