Metabolic profile of ewes submitted to hipertryacilglyceremia and treated with recombinant bovine somatotropin (r-bST)

Abstract

Diseases of nutritional and metabolic nature such as ketosis, fatty liver (FG) and Toxemia of Pregnancy (TP) commonly affect sheep overnutritioned with the accumulation of body fat and are characterized by increased non-esterified fatty acids (NEFA) in blood and intense formation of ketone bodies leading to hepatic lipidosis. Treatment relies on supportive therapy, most often consisting of solutions containing glucose or glucose precursors and electrolyte solutions. The bovine somatotropin (bST) appears as an alternative treatment for acting in the partitioning of nutrients, especially for muscle and adipose tissues, and to act in the main metabolic pathways of the body. Among the effects of bST stands, increased hepatic gluconeogenesis, decreased glucose oxidation, increased oxidation of NEFA, acts as an antagonist of glucose and provides greater efficiency of amino acid deposition. Thus, this study aims to experimentally induce hipertriacilgliceremia in sheep and to evaluate the possible benefit of metaphylactic treatment with recombinant bovine somatotropin (r-bST) by assessing the metabolic profile. 20 sheep will be distributed in two groups of 10 animals, a) group treated with r-bST 3 days before induction and b) Control - treated with physiologic solution. Animals will be evaluated at the follow moments: M-21, M-3 (days before induction), M0 (basal), at 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112 and 120 hours after induction. Blood samples will be collected into vacuum collection tubes to obtain serum and plasma to determine the concentrations of the following biochemical and hormonal variables: total protein, albumin, urea, creatinine, calcium, triglycerides, total cholesterol, insulin, IGF-1 and activities of AST, GGT and CK in serum and glucose, NEFA and B-hydroxybutyrate. Haemogasometric for analysis, whole blood is collected in 3 mL syringes containing heparin for determination of pH, pressure, CO2, O2, HCO3 and ABE. Urine samples will be collected by urethral probe or mechanical stimulation to determine the pH, urine specific gravity and ketone bodies. Liver samples, collected throughout video laparoscopy only at M-21 and at the end of study, will be used to determine the levels of triacylglycerol (TAG) and glycerol by colorimetry. A complete haematological profile will be determinate. All variables will be submitted to Kolgomorov-Smirnov test to verify that the data have normal distribution. Variables with non-normal distribution will be compared by the Mann-Whitney test. For variables with normal distribution is used to analysis of variance for repeated measures, with post-test bonferoni to compare the treated and control groups. To study the relationships between variables will be used as a linear regression analysis and the study of the correlation coefficient.