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Abstract. Macrobrachium rosenbergii is being favored for farming due to its large size. However, like other crustaceans, it is also prone to bacterial and viral infections. Turmeric, a derivative of the plant Curcuma longa, is a spice commonly used in Middle East and Asia as an herbal remedy. Immuno-modulatory effects of turmeric powder on hemocyte population and expression of antimicrobial peptides (AMPs) of M. rosenbergii challenged with Vibrio alginolyticus was investigated. Eighty (80) juveniles of M. rosenbergii were divided into three groups labeled as D0, D1 and D7 (Day 0, 1 and 7 respectively). D0 were fed with commercial feeds while D1 and D7 were fed with turmeric-incorporated (enhanced) feeds for one and seven days respectively. The total hemocyte count (THC) of D0 remained constant and a significant increase was observed from D1 to D7 treatment. Prawns were challenged with V. alginolyticus and total RNA was isolated and synthesized into cDNAs from hepatopancreas. RT-PCR was performed with crustin and lysozyme as target genes and EF-1α as the reference gene. PCR products were run through 1% agarose gel electrophoresis. Semi-quantitative RT-PCR revealed an increasing expression of crustin and lysozyme PCR relative to duration of feeding, indicating a remarkable increase in the expression of AMPs (antimicrobial peptides). Challenged prawns fed with enhanced feeds also had an induced expression of AMPs. It is noteworthy to mention that this is the first report on AMPs expression in M. rosenbergii.
Key Words: shrimp biotechnology, Curcuma longa, Macrobrachium rosenbergii, crustin, lysozyme.
Introduction
The Philippines and other Asia-Pacific countries play a major role in the world aquaculture shrimp trade industry. Shrimp farming has been promoted because of its economic importance but, in the past few years, the industry has been plagued with environmental pollution, degradation and pathogen proliferation, resulting in poor production and mass mortality due to diseases. One of the important species being cultured nowadays is Macrobrachium rosenbergii (De Man, 1879) or giant freshwater prawn (Kennedy et al 2006). It is the largest species in its genus, thus being favored for farming and suited for inclusion in polyculture systems, and in integrated aquaculture-agriculture (Nhan et al 2009). However, this species like any other commercially farmed shrimps is also prone to viral and bacterial infection. Vibrio alginolyticus Sakazaki, 1968 is an...