THE EFFECT OF PREVIOUS GROWTH-RETARDATION ON ENERGY AND NITROGEN-METABOLISM OF GOATS INFECTED WITH TRYPANOSOMA-VIVAX

The effect of growth retardation, resulting from feed restriction for a prolonged period, on the course of infection with Trypanosoma vivax was studied. Twelve male castrated West African Dwarf goats were subje cted to a restricted feeding regimen of 55 g pelleted lucerne (Medicag o sativa)/kg body weight(0.75) per d for on average 17 weeks. Twelve o ther animals were fed on pelleted lucerne ad libitum, resulting in a n ormal growth pattern. After this period, all animals were fed on pelle ted lucerne ad libitum, and six animals of each previous feeding regim en treatment were infected with Trypanosoma vivax. The other animals s erved as controls. In week 2 and 4 post infection (pi) energy and N ba lances were measured. In the week before infection and during infectio n blood biochemical and clinical variables were measured. At 2 weeks b efore, and 4 weeks after infection, a liver biopsy was taken for measu rement of triacylglycerol. Infection caused intermittent fever and ana emia, The first peak of fever persisted longer in infected animals wit h normal growth than in infected animals with retarded growth. Gross e nergy and metabolizable energy intake, and energy retention were reduc ed in infected animals. Metabolizable energy requirements for maintena nce were increased by infection. Plasma non-esterified fatty acids (NE FA) and glucose concentrations were increased in infected animals, whe reas serum triiodothyronine and thyroxine concentrations were decrease d. Plasma urea concentration and liver triacylglycerol were unaffected . No interaction of growth retardation with infection with respect to blood biochemical variables was found, apart from plasma NEFA in week 2 pi. N retention was not significantly affected by treatments. In con clusion, minor indications were found for an interaction between growt h retardation, as applied in the present study, and trypanosomiasis in fection in West African Dwarf goats with respect to energy and N metab olism.