Effect of different quantities of artificial substrates on shrimp Litopenaeus vannamei (Boone, 1931) grow out, in semi-intensive culture system

Abstract

The use of artificial substrates, that help the development of biofilm or periphyton, enhances phyto and zoobenthos productivity within ponds in a tri-dimensional space. Benthic omnivorous organisms, like shrimp, take advantage of biofilms from nourishment and the maintenance of more adequate levels of water quality parameters. The present study evaluated the effects of increasing amounts of a high surface vertical substrate (0, 15, 30 and 45% of bottom area) over growth, survival, food demand, productivity and feed conversion ratio of Litopenaeus vannamei reared in pens (n=3) built into a semi-intensive managed earthen pond. Commercial feed was offered 3 times a day through feeding trays for 6 weeks. Growth and feed conversion ratio were not affected by the presence of substrates (P>0.05); however, independent from the amount of substrates, survival, demand for food and productivity were about 20% greater than control (P<0.05). An oscillatory and increasing pattern on food demand was observed, probably associated to molting peaks and environmental stresses. Even with abundant availability of biofilm, commercial feed remained essential and proportional to cultured biomass. Results suggest that the effect of artificial substrates on L. vannamei production in semi-intensive systems can be achieved with a substrate area even less than 15% of the bottom area.