Summary investigations on the nutrition of guinea pigs .2. Energy and protein requirements

In digestive and balance trials data were collected on the energy and protein requirements of guinea pigs. The animals were fed on 16 different rations (hay, grass, concentrate, semisynthetic diets) for the evaluation of faecal and urinary N-losses. In the blood the concentrations of triglycerides, cholesterin, protein, albumin, creatinine, bilirubin and the activities of ALT, GLDH, aP were measured. The energy requirement for maintenance in adult guinea pigs was estimated to be 0.5 MJ DE/kg BW/d. The restriction of energy intake induced weight loss, while plasma cholesterin and triglycerides were not affected. There were no signs of ketosis due to energy deficiency. For the factorial calculation of protein requirements of adult guinea pigs endogenous N-losses were estimated from the balance studies, amounting to 0.07 (faecal) and 0.09 (renal) g/kg BW/d, while dermal losses were estimated to reach 0.02 g/kg BW/d. The losses are in total 0.18-0.2 g N/kg BW/d, indicating a protein requirement of 3 g crude protein/kg BW/d by the assumption of average utilisation rates. A complete diet for adult guinea pigs should contain 10% crude protein (DM) with an average intake of 40-60 g dry matter /kg BW/d. A diet with 5.2% crude protein (DM) induced protein deficiency, including weight loss, dermatitis and alopecia and lower concentrations of protein, albumin and urea in the blood. Realimentation was possible by a diet with 10.6% crude protein. It can be concluded that adult guinea pigs will show clear symptoms of protein deficiency in a short time span, if fed on inadequate or low digestible diets. Low energy intake induced only weight loss, while the general health was not affected, and signs of fasting ketosis were not seen.