This chapter presents the background of the problem, main problem, the sub-problems, and hypothesis, significance of the study and the scope and limitations of the study. Background of the Problem
Nile Tilapia (Oreochromis niloticus) is a very popular aquaculture species in the Philippines at present and considered as an “aquatic chicken” offering economical and social benefits mainly for rural communities. It also play vital role in terms of worldwide employment, however there were reported cases of high mortality rates in different species of Tilapia cause by Aeromonas species (Badillo, 2010). One of the most common bacteria that infect the wild and cultured Tilapia is Aeromonas sobria. Aeromonas sobria is water borne pathogen that are common in almost all aquatic environments including fresh, brackish and marine water. They cause fin rot or skin rot disease and may lead to heavy mortality in cultured tilapia (El-Sayed, 2006). Aeromonas sobria veronii also causes a similar disease in fish including Motile Aeromonas Septicemia in Tilapia (Janda and Abbott, 2010). Bacterial infections, caused by motile members of the genus Aeromonas are among the most common and troublesome diseases of fish raised in ponds and recirculating systems. The Motile Aeromonas infections have been recognized for many years and have been referred to by various names, including Motile Aeromonad Septicemia (MAS), Motile Aeromonad Infection (MAI), hemorrhagic septicemia, red pest, and red sore (Camus, Durborow, Hemstreet, Thune and Hawke, 2012). One of the most common treatment for the skin lesions, fin rots and infections caused by Aeromonas sobria is the use of chemicals specifically tetracycline. However, in 2012, Romero, Feijoo and Navarette stated that fish do not effectively metabolize antibiotics and will pass them largely unused back into the environment in the form of feces. It also been estimated that 75% of antibiotic fed to fish are excreted into the water. In 2000, Cruz-Lacienda, Dela Pena, Lumanlan-Layo also stated that chemical control such as antibiotics may lead to development of drug resistance bacterial strain through overuse and misuse of antimicrobial. Regarding to these problems, there is an urgent discovery of new drugs and alternative therapies to control bacterial diseases. According to the study of Krishnaiah et al. 2009 as cited by Namuli, Abdullah, Sieo, Zuhainis and Oskoueian 2011, plant secondary metabolites (alkaloids, terpenoids and phenolic compounds) are potential antimicrobial agents that can help to alleviate problem of antibiotic resistance. Treatments of bacterial diseases with medicinal plants having antibacterial activity are potentially beneficial alternative in aquaculture (Pandey, Sharma and Mandloi, 2012). Jatropha curcas (Tuba-tuba), belongs to the Family Euphorbiacaea, has been initially considered a traditional herb in many parts of the world. Different parts of Jatropha curcas have been used in treating different forms of infection. According to Igbinosa et al. and Akinpelu et al. (2009) as cited by Namuli, Abdullah, Sieo, Zuhainis and Oskoueian, 2011, the presence of Flavonoids and saponin in Jatropha curcas stem bark and leaves extract respectively was observed also gallic acid has been reported in the leaves extract of Tuba-tuba plant. Tinospora crispa (Makabuhay), belongs to the Family Menispermaceae, is a climbing vine plant. Leaves yielded picroretine, traces of an alkaloid. Both are found to be an antibacterial agent. Hence, this study aims to develop an alternative antibacterial agent from Jatropha curcas (Tuba-tuba) and Tinospora crispa (Makabuhay) against Aeromonas sobria veronii causing Motile Aeromonad Septicemia in Oreochromis niloticus (Nile Tilapia) also at the same time it aims not to harm both fish and environment.
Statement of the Problem
The study dealt with the determination of antibacterial activity of leaf extract of Jatropha curcas...