Quantitative immunoassay of the pro ventricular contents of white shrimp Penaeus setiferus Linnaeus: a laboratory study

Abstract

Immunological methods for gut contents analysis have been used successfully as a qualitative tool for defining the dietary composition of various invertebrate predators in the marine environment. Controlled laboratory feeding experiments were conducted with Penaeus setiferus (Linnaeus, 1767) fed known quantities of a single prey item to determine whether a quantitative relationship existed between the intensity of the immunological response and the amount of food ingested. Shrimp were fed morsels of the oyster Crassostrea virginica (Gmelin, 1791) laced with fluorescent pigments so that accurate timing of ingestion could be monitored visually. Rocket immunoelectrophoresis (RIE) was used to measure solubilized prey protein concentrations in the pro ventricular contents of the shrimp at various times after the meal was eaten. RIE results agreed well with independent gravimetric data on the amounts removed from the proventriculus, and oyster meals could be immunologically quantified reliably for up to 3 h after ingestion. Future quantification of diet using immunoassays will require similar laboratory verification and should be most successful when applied to predators having a region of the gut with minimal enzyme activity and a rapid passage time.