Effects of total parenteral nutrition associated with glutamine, enteral fluid therapy with or without glutamine, and fluid therapy on the acid–base and electrolyte balance of horses starved after exploratory laparotomy

Abstract This study aimed to evaluate the effects of the total parenteral nutrition associated with glutamine, enteral fluid therapy with or without glutamine, and fluid therapy on the acid–base and electrolyte balance of horses starved after exploratory laparotomy. Sixteen healthy male and female adult horses of mixed breed, aged between 4 and 14 years, and having a mean body weight of 248.40 ± 2.28 kg and a body score index of 3–4 (scale of 1–5) were divided into four groups with four animals per group. After an adaptation period of 30 days, they were randomly divided into four experimental groups: enteral fluid therapy, enteral fluid therapy associated with glutamine, total parenteral nutrition associated with glutamine, and parenteral fluid therapy. The experiment was further divided into two phases: Phase 1 and Phase 2. In Phase 1, an exploratory laparotomy was performed, treatments were administered to the groups and the horses received no food or water other than those given to their respective groups. In Phase 2, the animals were re-fed. Each phase had a total duration of 144 h. Venous blood samples were collected every 24 h throughout the experimental period for blood gas and electrolyte analyses. The following parameters were evaluated: pH, partial pressure of carbon dioxide, total carbon dioxide, bicarbonate, base shift, anion gap, sodium, potassium, chloride, total calcium and magnesium. Completely randomized designs with a 4 × 7 factorial scheme (groups × harvest time) in Phase 1 and a 4 × 6 factorial scheme (groups × harvest time) in Phase 2 were used with four replications. All values were considered significant when p≤0.05 (95% probability). Blood pH, bicarbonate concentration, and base shift in the PARGL group decreased, indicating metabolic acidosis. Changes in the acid–base and electrolyte balance were more intense in the PARGL group than in the other groups. These results demonstrated the need to monitor blood gas and electrolyte balance in horses with food restriction under nutritional support or prolonged fluid therapy so that such changes are promptly corrected.