ABSTRACT
BACKGROUND: Gastrointestinal and other systemic diseases of Equidae are often characterised by partial or complete inappetence. The catabolic processes may lead to lipid mobilisation and other metabolic disturbances. Evidence from earlier studies has revealed that during feed deprivation/inappetence, the conjugation of bilirubin is reduced causing a substantial rise of the total bilirubin and its unconjugated fraction. OBJECTIVES: We hypothesised that during feed deprivation, the serum concentration of free fatty acids (FFA), triglycerides (TG), blood urea nitrogen (BUN), total bilirubin (tBIL), total bile acids (tBA) and activity of GGT and GLDH increases, while the concentration of insulin and direct bilirubin (dBIL) decreases. STUDY DESIGN: Observational experiment. METHODS: Eleven horses were feed deprived for 96 h. Animals were closely monitored while blood samples were taken at the beginning, and then at 72, 84 and 96 h later. Variables of interest included serum FFA, TG, insulin, GGT, GLDH, total and direct BIL (t&dBIL), tBA and BUN. The data were analysed by descriptive statistics, paired t-test and one-way repeated measures ANOVA with post-hoc HSD test, and P≤0.05 was considered significant. RESULTS: Horses tolerated feed restriction without complications. During this time, the concentration of TG, FFA, BUN, dBIL and insulin significantly increased (P≤0.05), as well as the activity of serum GGT, while the concentration of tBIL, tBA and the activity of GLDH did not change significantly (P>0.05). MAIN LIMITATIONS: Sample size, lack of serum volatile fatty acid, cortisol and blood glucose measurements may have limited the value of the study. CONCLUSIONS: Healthy Akhal Teke horses did not develop a catabolic crisis following 4 days of feed restriction and hyperlipaemia did not occur. Total BIL and tBA did not increase, thus were not useful indicators of inappetence in this group of horses.
