A modified chamber designed for estimation of digestibility in shrimp

The science of the feeding and nutrition of crustaceans is still in develop ment, and producers and feed manufacturers need better understanding of the digestibility of various nutrients. The most widely used method of determi ning digestibility in vivo in fish is based on the measurement of chromium oxide (which is incorporated into the diet) in feces. To use this method, i t is essential to have an efficient means of collecting feces in the aquati c environment. In shrimp, this presents some difficulties because of their benthic feeding and coprophagic habits. This paper describes the developmen t and testing of a low-cost modification of the "Guelph" system used for fi sh that allows the collection of feces from shrimp. The system performed ex tremely well and had clear advantages over the basic siphon system. The imp ortance of having an easy and efficient method of collecting feces for in v ivo assays is discussed.