Dietary fatty acid profiles shape crayfish biosynthesis and performance: Implications for riverine food webs

Alteration of riverine flows can modify the structure and function ecosystems, changing energy pathways patterns micronutrient transfer between trophic levels. Fatty acids (FAs) commonly are used to evaluate food quality, since some FAs required for somatic growth physiological functions in animals must be obtained from their diet. also food-web studies as biotracers a consequence constrained metabolic biosynthesis by animals. However, utility may confounded selective retention or modification dietary consumers. We conducted 70-day feeding trial compare survival an abundant widespread mesoconsumer (Cherax destructor, common yabby crayfish) fed three contrasting diets: poor-quality detritus-based diet; high protein invertebrate high-quality commercial aquaculture pellet. acid profiles were each treatment contrasted with crayfish FA at end experiment examine integration. collected wild floodplain wetland river habitats, stomach contents body tissue experimental crayfish. Experimental pellets doubled mass during assay, was intermediate, detritus negligible. our diets differed significantly experiment. Proportions polyunsaturated omega-6 linoleic (LIN, 18:2ω6) followed same inequality observed > invertebrates detritus. Pellet-fed preferentially assimilated greater proportions 20:4ω6 (ARA), 20:5ω3 (EPA) 18:1ω9 (OA) 16:1ω7 (POA) into tissue. crayfish, had higher essential ARA LIN tissues. best described hypothesis allostasis rather than homeostasis; this, shaped diet, integration basal resources rich these micronutrients led Here we present evidence conversion shorter-chain freshwater compensate lack long-chain provide necessary step improving understanding dynamics molecules levels lowland webs. Floodplain habitats known higher-quality mesoconsumers here identify one mechanism which that extended subsequent