RESUMO

Ovine pregnancy toxaemia is a metabolic disorder affecting sheep in their last 6 weeks of pregnancy as a result of their inability to maintain adequate energy homoeostasis. Different alternative treatments are available with variable results. The aim of this research was to evaluate a peroxisome proliferator-activated receptor alpha (PPARα) stimulant as an alternative to treat clinical pregnancy toxaemia. Thirty-three adult sheep, with known gestation date and carrying a single foetus, were fasted from day 130 of gestation until animals showed clinical disease. From that moment onwards, sheep were treated during 6 days with three different therapeutic alternatives: 10 mg/kg of 2-methyl-2-phenoxy-propionic acid; 10 mg/kg of 2-methyl-2-phenoxy-propionic acid + 100 mL of propylene glycol oral; or 100 mL of propylene glycol oral. Glycaemia and serum ß-hydroxybutyrate (BHOB) were determined daily. Liver biopsies were taken at day 130 of gestation, at the beginning and end of treatments and at 5 days postpartum, evaluating the extent and degree of the steatosis lesion. Even though in sheep treated with 2-methyl-2-phenoxy-propionic acid, serum concentrations of glucose and BHOB recovered more slowly, we conclude that 2-methyl-2-phenoxy-propionic acid alone or combined with propylene glycol can be used as an alternative to effectively treat fatty liver, and therefore pregnancy toxaemia.

Assuntos

RESUMO

BACKGROUND: Ovine pregnancy toxaemia is a common metabolic disorder of ewes due to increased foetal energy requirements in late pregnancy. This pathology is a metabolic condition characterized by hypoglycaemia and hyperketonaemia resulting in the inability of the animal to maintain an adequate energy balance. The response to treatment is effective, if it is started in the early stages of the disease, when irreversible neurological injuries have not yet been established. The aim was to evaluate three therapeutic alternatives to effectively reverse the disease process in its early stages. For this, thirty adult Corriedale ewes, pregnant with a single lamb, were randomly separated in three groups of ten animals each, at day 130 of gestation. From that day onwards, ewes were locked up for forage fasting until glycaemia reached clinical values defining sub-clinical pregnancy toxaemia (1.59 ± 0.24 mmol/L). After fasting, ewes grazed and received a treatment for 4 days: 50 ml i.v. infusions of hypertonic glucose and 20 UI insulin/ewe/day s.c. or 100 ml/sheep/12 h of glycerol together with propylene glycol oral solution or fed with pasture supplemented with two daily intakes 300 g/sheep of cracked corn. Glycaemia and ß-hydroxybutyrate were determined in all the animals from the beginning of fasting until the completion of the treatment. RESULTS: Fasting caused a decline in blood glucose in the 3 groups. This decline continued until fasting was withdrawn and treatment began. Thereafter blood glucose increased in all three groups, although in the group supplemented with glycerol and propylene glycol it started to increase significantly after 12 h. The values of ß-hydroxybutyrate decreased in the 3 groups at the start of treatment, and this decline was more pronounced earlier on and in the group supplemented with glycerol and propylene glycol. We found no significant differences between all experimental groups. No animal showed clinical signs of pregnancy toxaemia throughout the research. CONCLUSIONS: The three treatments administered to sheep affected by sub-clinical pregnancy toxaemia were able to restore normal concentration of glucose and ß-hydroxybutyrate in blood, although per os administration of 100 ml/sheep/12 h of glycerol with propylene glycol, was the most successful treatment, normalizing the aforementioned biochemical parameters in a shorter time.

RESUMO

AIM: To detect early changes in the metabolic profile of pregnant ewes subject to acute feed restriction at 130 days of gestation, and to establish indicators of risk for ovine pregnancy toxaemia (OPT) for diagnostic purposes. METHODS: Twenty Corriedale ewes with known mating dates, carrying a single fetus, were used. Ewes were maintained on meadow grasslands and at 130 days of gestation were randomly divided in two groups of 10 ewes. The control group had ad libitum access to pasture. Ewes in the restricted group were subjected to an acute feed restriction for a maximum of 144 hours (6 days), with free access to water. From the start (0 hours) until the end of feed restriction, blood samples were collected from all ewes to monitor concentrations of cortisol, non-esterified fatty acids (NEFA), ß-hydroxybutyrate (BOHB) daily, and glucose in plasma every 6 hours; urinary pH was also measured. Every 6 hours the food restricted ewes were observed to detect clinical signs of OPT e.g. apathy, grinding teeth, empty chewing movements, head leaning against the wall, tachypnea and not drinking water. RESULTS: In food-restricted ewes, concentrations of glucose decreased and differed from control ewes from 54 to 90 hours (p<0.001), and 96 to 102 hours (p<0.05). Concentrations of BOHB, cortisol and NEFA increased following feed restriction and differed from control ewes after 48 to 144 hours (p<0.01). Eight of the 10 restricted ewes showed clinical signs of OPT after 102-132 hours. Mean concentrations of glucose, BOHB and cortisol differed between control and restricted ewes prior to the onset of clinical signs of OPT, after 48-96 hours of feed restriction (p<0.01). Mean gestational length, and time from birth to placental expulsion was not affected by the feed restriction. CONCLUSIONS: Our results suggest that concentrations of glucose, BOHB and cortisol in plasma may provide a precocious diagnosis of subclinical OPT, using values of 1.59 (SD 0.24) mmol/L, 2.26 (SD 1.03) mmol/L and 15.09 (SD 7.75) nmol/L, respectively. The identification of a potentially harmful metabolic imbalance could lead to the improvement of treatment success.

Assuntos