Effect of attractant and food availability on digestive enzymes in the redclaw crayfish Cherax quadricarinatus (Parastacidae)

HERNÁN J. SACRISTÁN; HÉCTOR NOLASCO-SORIA; LAURA S. LÓPEZ GRECO

San José

Congreso; Summer Meeting of The Crustacean Society (TCS) jointly organized with the Latin American Association of Carcinology (ALCARCINUS); 2013

The Crustacean Society

Food is an important cost in aquaculture so it?s necessary to improve feeding strategies. Chemoreception plays a significant role in the feeding behavior thus it is logical to assume that incorporation of attractants/feeding stimulants in pellets will improve consumption avoiding nutrients losses. This study analyzed the effect of the inclusion of squid meal (attractant) on feeding behavior and the effect of food availability on digestive enzymes in juveniles of C. quadricarinatus. The composition of feed base (FB) was: 37.98% of protein, 6.05% of lipid and 16.05% of ash and the attractant concentration ranged from 0 to 10%; TETRACOLOR® food was selected as positive control. Behavior of 20 juveniles per treatment was observed in a glass aquarium divided into three compartiments. To evaluate which was their first choice (attractant or not attractant) and the time of residence in each compartment, we recorded 10 minutes. The results showed that the inclusion of squid meal did not act as attractant for this species. The effect of food availability on digestive enzymes after two days without food was assessed using the following treatments: no FB; available FB (phage-stimulated) and present but not available FB.The activity of  proteases, lipases and amylases at 5, 10, 30, 60 and 120 minutes post feeding was recorded. The results indicated that at the assayed conditions food availability did not modify the levels of digestive enzymes. These results would be reinforcing the concept that C. quadricarinatus is an omnivorous opportunistic species from fluctuating habitats adapted for some periods of food restriction.