, Diagnosis an-&& of Shrimp Diseases - Central Institute of ...

step would be to determine the route of administering the strain either by bath or by 111ixillgwith the feed. Finally economic evaluation has to be done to see whether it is worth theinvestment.ImnzunostimulffntsThe Invertebrates encounter all the usual sorts of challenges to self-integrity. Theirhabitats are laden with infectious agents: viruses, bacteria, fungi, protists, and other animals.Shrimps have innate defense systems, including the phagocytic cells, production of toxicoxygen and nitrogen metabolites, and melanization pathways, use of RNA interference(RNAi), pattern-recognition receptors (PRRs), anti-microbial peptides (AMPS), whicheffectively help in combating infection. However, with the advancement in aquacultilretechnology, application of extraneous substances to boost immune system of shrimps hascome into practice. These are usually chemical substances, which aid animals (shrimp) indefending themselves against disease outbreaks and are called immunostimulants. P-1, 3 1 1,6- glucans have been reported to be most promising substances with i~n~nunosti~nulatoryproperlies. A number of other substances, such as laminarin, chitosan, saponins, barleyglucans, lactoferrin, zymosan, dextran, peptidoglycans (PG), lipopolysaccharides (LPS),inulin, levamisole, herbal extracts, etc. are also reported to he useful in enhancing shrimpimmune system.Plz age Tlz empyWith the developn~ents in aquaculture and associated disease outbreaks, use of antibioticsand therapeutants has also substantially increased over the years. Bacteria resistant to most orall available antibiotics are increasingly causing serious problems, raising widespread fearsof returning to a pre-antibiotic era of untreatable infections and epidemics. As an alternativeto the use of antimicrobial agents against the pathogenic bacteria, the possibilities of using aspecific kind of virus that attack only pathogenic microorganisms (phage therapy) appears tobe promising. Almost a century ago, Hankin had reported that the waters of the Ganges andJamuna rivers in India had marked antibacterial action, which could pass through a very fineporcelain filter. He also had reported that boiling destroyed this activity. He partic~~larlystudied the effects 011Vibrio cholerae and suggested that the s~tbstance responsible keptcholera epidemics from spreading by ingestion of the water of these rivers. This filterablesitbstance was nothing but the viruses (called as bacteriopl~ages) that specifically affectedYibrio cholerae and brought about their lysis and killing. This and several initial studies gave