EFFECT OF DIFFERENT FEEDING PROTOCOLS IN JUVENILES OF THE RED CLAW CRAYFISH, Cherax quadricarinatus

NATALIA S. CALVO, LIANE STUMPF, LAURA S. LOPEZ GRECO*

VERACRUZ, MEXICO

Congreso; WAS AQUACULTURE 2009; 2009

WAS AQUACULTURE SOCIETY

effect of different feeding protocols in juvenileS OF THE RED CLAW  crayfish,  Cherax quadricarinatus  Natalia S. Calvo, Liane Stumpf, Laura S. López Greco* Dept. of Biodiversity and Experimental Biology, FCEyN, University of Buenos Aires Ciudad Univ. C1428EHA, Buenos Aires, Argentina. laura@bg.fcen.uba.ar Cherax quadricarinatus is an Australian freshwater crayfish that is nowadays cultured in several countries, including Argentina. The effects of different feeding treatments in juveniles of stage III were studied with the purpose of diminishing the production cost and improving the survival during early development. A total of 840 juveniles were used and assigned to 40 feeding protocols: 19 feeding treatments ©¤with a different number of feeding days from 1 to 19©¤ followed by starvation, 19 starvation treatments ©¤with a different number of starvation days from 1 to 19 ©¤ followed by continuous feeding and 2 controls, continuous starvation (IC) and continuous feeding (AC). The experiment finished when all the juveniles molted or died. The weight after molt and the number of molts/deaths per treatment were recorded. The results indicated that after 2 days of feeding, 50% of the juveniles molted. None of the juveniles molted either in IC or in one day feeding treatment (Fig 1A). The time until molting was independent (p>0.05) of the number of feeding days. Weight gain was lower (p<0.05) in two days feeding treatment with a value of 14.13%. The other treatments had a weight gain in a range of 28 to 57%. The starvation treatments showed a tendency to delay and decrease frequency in molt. The 50% of the molts occurred within a maximum of 6-8 starvation days (Fig. 1B). The treatments in which juveniles could molt showed that neither the final weight nor weight gain differed (p>0.05) in relation to AC, with values between 17 and 68%. Figure 1. Percentage of molted juveniles for the feeding treatment (A) and starvation treatment (B) To summarize, the results reflect that two days of feeding are enough for a successful molt and three days are necessary to obtain a similar weight as with continuous feeding regime (AC). The reduction or lack of food, during the following days, would not directly affect either the molt or growth. Thus, this would improve water quality and reduce costs. Future studies will evaluate if this reduction in food affects the posterior development or survival.   Financial support: UBACYT X 458; PIP: 112-200801-00129 and PICT 2007 area: PESCA: 01187. We wish to thank Lic. Carlos Anselmi/ Farm Las Golondrinas SRL, Argentina for supplying the crayfishes.