Resistance to parasites in lactating rats is sensitive to protein but not energy supply

Abstract

. However, effects of CPintake were confounded with metabolizable energy (ME) intake as a result of increased food intake on the high-protein diets. Here, effectsof CP and ME supply on PPRI were independently assessed.Second-parity rats were infected with 1600 N. brasiliensis larvae before mating (primary infection). On parturition dams were allocatedto one of six feeding treatments (1–6) consisting of two levels of ME supply at one of three levels of CP supply; feeding treatments werebalanced for parturition body weight (PBW; n 14). Feeding treatments 1, 2 and 3 were calculated to supply 1.05MJME/kg PBW per d,whereas treatments 4, 5 and 6 were calculated to supply 1.40MJME/kg PBW per d. In addition, CP supply was calculated to incre-mentally increase from scarce to more than adequate at each level of ME intake: 6.6, 13.3 and 19.9g/kg PBW per d for feeding treatments1, 2 and 3 respectively; 13.3, 19.9 and 26.5g/kg PBW per d for treatments 4, 5 and 6 respectively. Rats were re-infected with 1600 N.brasiliensis larvae on day 2 of lactation (secondary infection), when litter size was standardized at ten pups. Dams and litters wereweighed daily until either on day 8 or day 11 of lactation when worm burdens (number and gender) were assessed as a proxy for PPRI.