S.N. Mohanty

Larval survival and growth in Wallago attu (Bloch and Schneider): effects of light, photoperiod and feeding regimes

Abstract An in-door rearing study was conducted for 11 days with Wallago attu larvae fed on live zooplankton alone (control) or combinations of zooplankton and dry feed containing either fish meal (F1), meat meal (F2) or shrimp meal (F3) under 24 h continuous light (24L), 12 h light–12 h dark (12L:12D), 24 h red light (24RL) or complete darkness (0L). The percent survival of larvae was significantly different (P

Phenotypic and genetic characterization of Edwardsiella tarda isolated from pond sediments.

The extent of genotypic and phenotypic diversity of Edwardsiella tarda isolated from pond sediment was assessed by SDS-PAGE, Plasmid Profiling and ERIC-PCR. SDS-PAGE of whole cell protein extracts reveals 20-23 discrete bands with molecular wt of 14-110 kDa. Several bands with molecular weight range of 38-83 kDa were present in all the isolates. Numerical analysis of protein electrophoregram delineated the isolates into four clusters. Two different types of plasmids having molecular mass of 23 kDa and 29 kDa were obtained by plasmid profiling. About 51% of the isolates carried both the plasmids. ERIC-PCR generates 3-7 bands with molecular mass of 14-1013 bp. Numerical analysis differentiated the ERIC pattern into 5 clusters at 60% similarly level. It was concluded that out of three methods ERIC-PCR was found to be more sensitive for intraspecific typing of E. tarda and can be used as a potential tool for epidemiological studies in the future.

Characterization of Vibrio species isolated from freshwater fishes by ribotyping

Three Vibrio species from the resident microflora of gastrointestinal tract of freshwater carps and prawns were isolated and confirmed biochemically as V. fluvialis from Cyprinus carpio/Labeo rohita; V. parahaemolyticus from Macrobrachium rosenbergii and V. harveyi from Macrobrachium malcomsoni. The genetic relationship among these Vibrio species was carried out by polymerase chain reaction (PCR) amplification of 16S rRNA gene followed by restriction digestion with Hae III, Bam HI and Pst I. Dendogram based on ribotyping showed the isolated Vibrios were differentiated into three clusters. V. harveyi was closely related to V. vulnificus (reference Microbial type Culture Collection (MTCC) strain) and distantly related to V. parahaemolyticus as well as V. fluvialis.