Background: Ketosis is a metabolic disorder often triggered by anorexia in animals fed on high energy diets. Although mostly described in pregnant female guinea pigs, under the name of pregnancy toxicosis; there is limited information on ketosis in males and non-pregnant females, often presented to clinics with anorexia or inappetence. The objective of this study was to observe progression of ketosis in guinea pigs, document the changes and evaluate diagnostic methods and a therapeutic approach.
Results: Twenty eight adult guinea pigs (Cavia porcellus), castrated males and intact females of obese and slim body condition were fasted for 3 days and refed afterwards. The slim animals served as control group for body condition. Either slim and fat animals were divided into two treatment groups: half of them received fluid replacements with glucose subcutaneously, the other half did not receive any injection and served as treatment control. Serum beta-hydroxybutyrate, and urine acetoacetate and acetone were measured during and after fasting. Serum ALT, bile acids and liver histology were also analyzed after 7 days of refeeding (and therapy). Females and obese guinea pigs showed a significantly higher increase in ketone bodies in serum and urine. Obese, female, or animals not receiving therapy needed more time to regulate ketone bodies to normal levels than slim animals, males or animals receiving therapy. Liver histology revealed increased hepatocyte degeneration and higher glycogen content in obese animals and animals receiving therapy, and additionally more glycogen content in males. Only minor hepatic fat accumulation was documented. Bile acids showed good correlation to histological liver changes whereas ALT did not.
Conclusions: Female and obese animals react more intensively to fasting. As preventive management, animals should be kept in adequate body condition, fasting should be avoided, and anorexia should be treated immediately. In such a case, urinary dip sticks to detect ketone bodies are a useful diagnostic tool. Glucose therapy leads to faster cessation of ketogenesis and should be recommended in cases of ketosis. However, it needs to be adjusted to avoid hepatocyte glycogen overload and degeneration. Measuring bile acids presents a valuable indicator of liver damage.
Keywords: Beta-Hydroxybutyrate; Bile acid; Fasting ketosis; Guinea pig; Liver damage.