Effect of Actinobacteria as a single cell protein on growth performance of Xiphophorus helleri

The potential of Marine Actinobacteria particularly Streptomyces as a single cell protein (SCP) feed for the growth of ornamental fish, Xiphophorus helleri has been investigated. The Streptomyces strains used as SCP were isolated from the marine sponges, namely Callyspongia diffusa, Mycale mytilorum, Tedania anhelans and Dysidea fragilis. Six SCP feeds were prepared and their effects were compared with those of control diet. After 30 days of feeding trials, the growth parameters including absolute growth rate, specific growth rate and feed conversion efficiency were found to be significantly (P < 0.001) higher in groups that received SCP feed than those of control one, whereas feed conversion ratio was lower. Thus it was found that in addition to being effective antibiotic agents against harmful pathogens, Streptomyces could also promote the growth of fish effectively. Marine Actinobacteria, particularly Streptomyces, could play an important role as a single cell protein (SCP) in aquaculture nutrition and is a promising microbe for the development of marine biotechnology.