Effect of lead on thyroid function in sheep

The objective of this experiment was to determine the effect of long-term low-dose administration of lead [Pb] on thyroid function in sheep. In this experiment 10 healthy Iranian male sheep, aged about one-year-old were randomly allocated into two equal groups of control [n = 5] and experiment [n = 5]. Both groups were kept under the same conditions of food and environment. The treatment group received lead acetate [5 mg/kg/day] orally for 8 weeks. Blood sampling of two groups was done on the same days, on days 0 [before receiving lead acetate in treatment group], 14, 28, 42, 56 and 70 after lead administration, every morning [8 to 9 a.m.]. The function of the thyroid was evaluated by measuring the levels of serum thyroid hormones T3, T4, FT3, FT4 and TSH. The hepatic function in both groups was evaluated by measuring hepatic enzyme activities including alanin amino transferase [ALT], aspartate aminotreansferase [AST], gamma glutamyl transferase [GGT], and total bilirubin [TBIL]. Serum levels of T3 [on days 14, 56 and 70] T4 [on days 14, 28, 42, 56 and 70], FT3 [on days 56 and 70], FT4 [on days 42, 56 and 70] and TSH [on days 14, 28, 42, 56 and 70] significantly decreased in lead-treated sheep when compared to the control group [P<0.05]. Serum enzyme activities of ALT [on days 28 and 42], AST [on days 28, 42, 56 and 70] and TBIL [on days 28 and 70] in Pb treated sheep increased significantly in comparison with the control group [P<0.05]. Our findings suggest that Pb exposed sheep can be at risk of low thyroid function

Study of the effects of experimental hypothyroidism on clinical hematological and serum biochemical factors in pregnant ewes

The objectives of this experiment were to determine clinical and clinicopathological changes in hypothyroid pregnant ewes [3-4 months]. Experiment was carried out using 12 Iranian crossbred ewes aged between 3-3.5 years old, with body weight 45-65 kg. The animals were divided into two groups, group A: 4 ewes as control and group B: 8 ewes for the experiment. Hypothyroidism was induced by giving thiourea 50 mg/kg body weight daily to each animal of group B. The respiratory, heart rates and temperature were measured. Blood samples were collected from the jugular vein, once weekly. At the end of experiment the animals became lethargic, weak and anemic. Finally, 4 ewes died, 2 ewes aborted and 2 ewes delivered stillbirth. There was a significant difference [P<0.05] between respiratory rate of group A and group B at the third and fourth weeks. The hematological analysis showed significant reduction in erythrocyte and leukocyte counts at the end of the experiment. The treated ewes showed significant hypoalbuminemia [P<0.05], hyperlipidemia [P<0.05] and hypercholesterolemia [P<0.01]. A significant decline [P<0.01] was detected in HDL as well as a significant increase [P<0.01] was observed in LDL serum levels of treated ewes. There was a highly significant decrease [P<0.01] in the values of T3 and T4. In conclusion, hypothyroidism in pregnant ewes leads to clinical and clinicopathological changes as well as abortion and stillbirth

Effects of experimental proximal duodenal obstruction on clinical, hematologieal, serum and urine biochemical changes in sheep

The objectives of this experiment were to determine clinical and clinicopathological changes after proximal duodenal obstruction in sheep. Experiments were carried out on seven Iranian crossbred male sheep aged between 2-2.5 years and weighing 45-50 kg. All operative procedures were performed under general anesthesia by intravenous infusion of sodium thiopental. A polyethylene tube reinforced with braided cotton tape was surgically placed around the duodenum 5 to 6 cm caudal to the pylorus. Experimental observations commenced two days before tightening the ligatures and inducing obstruction. Measurements at this stage were considered as the control values. Clinical [appetite, urination, defecation, ruminal contractions, temperature, respiratory and heart rates] and clinicopathological indices [hematological parameters, concentrations of sodium, chloride, potassium, calcium, magnesium, inorganic phosphorous, urea nitrogen, creatinine and acid-base status in serum and urine] were determined simultaneously at 12 hrs intervals for 72 hrs. At the end of the experiment the animals became lethargic, anorexic, weak and dehydrated. Finally, six sheep died and one sheep was slaughtered. There were significant differences [P<0.05] between temperature, respiratory and heart rates of the control and experimental values. Moreover, significant increases [P<0.05] in hematocrit, RBC and WBC counts, hypokalemia [P

Effects of experimental hyper- and hypocalcemia on bile flow and composition in sheep

Experiments were carried out on sixteen Iranian cross-bred sheep aged between 2-2.5 years old, with body weight between 35-45 kg. All operative procedures were performed under anaesthesia by intra-juguglar infusion of sodium thiopental. One cannula into the proximal duodenum and the second into gallbladder were inserted. Experiments commenced approximately 10 days after surgical preparations. Bile and blood samples were obtained simultaneously at one-hour intervals for six hours. Bile flow and concentrations of sodium, potassium, chloride, calcium, magnesium, cholesterol, bilirubins, total solids of bile and calcium of serum were measured. Bile flow and composition as well as calcium of serum in this stage were considered as control group. Hypercalcemia was induced by intra-jugular adminstration of calcium borogluconate. Blood and bile samples were obtained using the same procedure as control group. After 10 days, hypocalcemia was induced by intra-jugular adminstration of Na2EDTA. Blood and bile samples were obtained using the same procedure as control group. The results indicated that, bile flow decreased significantly in hypercalcemic group [P<0.05], but did not change significantly in hypocalcemic group. The concentrations of biliary calcium, total bilirubin, indirect bilirubin and total solids increased significantly in hypercalcemic group [P<0.05]. During hypocalcemia the concentration of biliary potassium decreased significantly [P<0.05]. Bile flow and biliary calcium decreased respectively and increased significantly more in male than in female sheep [P<0.05]. In conclusion hypercalcemia decreases bile flow and increases biliary calcium, but hypocalcemia did not change bile flow and biliary calcium