Improvement of Growth and Survival of the Juvenile Walking Catfish, Clarias batrachus (L.) (Siluriformes: Clariidae) Fed on Probiotics Encapsulated and Ascorbic Acid Enriched Chironomid Larvae (Diptera: Chironomidae)

Abstract

Effects of probiotics encapsulated and ascorbic acid enriched chironomid midge larvae as live feed on growth and survival of 12 day old Clarias batrachus juveniles (average weight 0.4 ± 0.06 g) were observed with feeding experiment for four weeks. Presumptive probiotic strains Bacillus aryabhattai KP784311, B. flexus KR809411, and B. cereus KR809412 were considered for bioencapsulation of chironomid larvae, and ascorbic acid (vitamin C) was used further for bioenrichment of the same. Seven experimental diets, D0: non-bioencapsulated and non-bioenriched chironomid larvae (control), D1: chironomid larvae bioencapsulated with B. aryabhattai, D2: chironomid larvae bioencapsulated with B. flexus, D3: chironomid larvae bioencapsulated with B. cereus, D4: chironomid larvae bioencapsulated with mixture of three strains, D5: chironomid larvae non-bioencapsulated and bioenriched with ascorbic acid, and D6: chironomid larvae bioencapsulated with probiotics and bioenriched with ascorbic acid were fed to triplicate groups. The juveniles were fed ad libitum for four weeks and the result of D6 group showed significantly higher (P < 0.05) specific growth rate and survivability than other groups. Although the RNA content in the carcass was increased initially in all dietary groups, any significant change of the DNA was not noticed. The coefficient (r value) of 0.992 in experiment 1 and 0.993 in experiment 2 along with regression slopes suggested a positive correlation (0.01 level) between RNA: DNA ratio and specific growth rate.