Dietary supply with polyunsaturated fatty acids and resulting maternal effects influence host - parasite interactions

Abstract

BackgroundInteractions between hosts and parasites can be substantially modulated by host nutrition.Polyunsaturated fatty acids (PUFAs) are essential dietary nutrients; they are indispensable as structural componentsof cell membranes and as precursors for eicosanoids, signalling molecules which act on reproduction andimmunity. Here, we explored the potential of dietary PUFAs to affect the course of parasitic infections using awell-established invertebrate host – parasite system, the freshwater herbivore Daphnia magna and its bacterialparasite Pasteuria ramosa.ResultsUsing natural food sources differing in their PUFA composition and by experimentally modifying theavailability of dietary arachidonic acid (ARA) and eicosapentaenoic acid (EPA) we examined PUFA-mediated effectsresulting from direct consumption as well as maternal effects on offspring of treated mothers. We found that bothhost and parasite were affected by food quality. Feeding on C20 PUFA-containing food sources resulted in higheroffspring production of hosts and these effects were conveyed to a great extent to the next generation. Whilefeeding on a diet containing high PUFA concentrations significantly reduced the likelihood of becoming infected,the infection success in the next generation increased whenever the maternal diet contained PUFAs. We suggestthat this opposing effect was caused by a trade-off between reproduction and immunity in the second generation.ConclusionsConsidering the direct and maternal effects of dietary PUFAs on host and parasite we propose thathost – parasite interactions and thus disease dynamics under natural conditions are subject to the availability ofdietary PUFAs.