Isolation and Characterisation of Probiotics from Gut flora on the Growth performance of Freshwater fish Channa marulius and Mugil cephalus

Abstract

In the present investigation, Part -I deals with the isolation of culturable newlinemicroorganisms from the intestinal content of fingerlings and adults of of Channa newlinemarulius and Mugil cephalus. 10bacterial strains were isolated from the gut of Mugil newlinecephalus were screened for antibacterial and antagonistic activity against two major newlinefish pathogens viz, PATHO-1- (Aeromonas Spp), and PATHO-2 (Vibrio Spp). Out of newline10 isolates from Channa marulius, 07 isolates showed zone of inhibition greater than newline10 mm against the fish pathogens. Better results were obtained from channa marulius newlineas compare to Mugil cephalus. The Cross streak method revealed that the five strains newlinein Mugil cephalus (CM-2, CM-4, and CM-10) show zone of inhibitions. The strain newlineCM-3 exhibited an inhibition zone greater than 10mm against all the test pathogens, newlineFollowed by the strains CM-9, CM-10, and CM-5 which produce an inhibition zone newlinegreater than 5 mm against the test pathogens. By its greater inhibition zone in the newlinecross streak method and positive antibacterial activity, CM-3 was selected for further newlineexperiments. newlineIn Part II, Five experimental diets containing varying concentration of newlineLactobacillus spp (probiotics) (0.25,0.5,0.70and 100%) were formulated using newlineprocessed full fat soybean as the protein source. The fish were exposed to their newlinerespective diet for 4h during each ration, Fish growth, digestibility and nutrient newlineretention result shows that survival was not affected by the inclusion levels of newlineprobiotic. Growth performance [(in terms of live weight gain), growth percent gain in newlineBW and final length), SGR and nutrient retention (PER, GPR, GER and APD)] newlineincreased when the dietary probiotic level was increased from 0.25g to 0.70g 100g-1 newlineof diet; further increase in dietary probiotic level (gt0.70g 100g-1) resulted in a newlinesignificant (Plt0.05) growth depression and nutrient depletion. Apparent protein newlinedigestibility was significantly (Plt0.05) higher in fish which were fed diets containing newlineprobiotic at 0.70g 100g-1 than in fish fed probiotics free diet (Contr