The current study was carried out to evaluate the effect of co-culture of white leg shrimp (Litopenaeus vannamei) with local seaweeds in the Mekong delta on water quality and feed efficiency. Experiment 1 consisting of six treatments with two stocking densities were applied in which shrimp postlarvae (PL) were mono-cultured at 30 and 60 PL/120L tank considered as controls; other four treatments PL were co-cultured with either red seaweed (Gracilaria sp.) or aquatic plant (Najas sp.). Shrimp in all treatments were fed commercial feed to satiation for 45 days. Experiment 2 comprised seven treatments with the same stocking density (20 PL/120L tank) where shrimp PL was mono-cultured and fed commercial feed at libitum as the control. The six remaining treatments, shrimp were co-cultured with either gut weed (Enterormorpha sp.) or blanket weed (Chaladophoracae) and fed at 75%, 50% and 25% compared to the control for 72 days. Two experiments were conducted in the static system at salinity of 10 ppt with three replicates for each treatment.

Results indicated that the survival rates of shrimps between mono-culture and co-culture in two experiments had no significant differences (P>0.05). In experiment 1, growth performances of shrimp in co-culture were superior to those in the mono-culture which was observed for both density treatments. Application of co-culture, feed conversion ratio (FCR) could be reduced from 23.2 to 28.1%. For experiment 2, the growth rate of shrimp in co- cultured fed 50 and 75% satiation were equal to or significantly higher (P2^- and NH₄⁺/NH₃ was observed during culture period. It was concluded that experimental seaweeds in the Mekong delta could be used for co-culture with white leg shrimp (L. vannamei) that can help to reduce the feed supply as well as maintain better water quality in the culture medium.

Keywords:  mono-culture, co-culture, water quality, Litopenaeus vannamei, seaweeds

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