Biology subjects

Sangpo, P.

Publications and source records attributed to Sangpo, P..

3 recordsLinked to original sources

bioRxiv2021

Ozone nanobubble treatments improve survivability of Nile tilapia (Oreochromis niloticus) challenged with a pathogenic multidrug-resistant Aeromonas hydrophila

Multidrug-resistant (MDR) bacteria has rapidly increased in aquaculture, which highlights the risk of production losses due to diseases and potential public health concerns. Previously, we reported that ozone nanobubbles (NB-O3) were effective at reducing concentrations of pathogenic bacteria in water and modulating fish immunity against pathogens; however, multiple treatments with direct NB-O3 exposures caused alterations to the gills of exposed-fish. Here, we set up a modified recirculation system (MRS) assembled with an NB-O3 device (MRS-NB-O3) to investigate whether MRS-NB-O3 were 1) safe for tilapia (Oreochromis niloticus), 2) effective at reducing bacterial load in rearing water, and 3) improved survivability of Nile tilapia following an immersion challenge with a lethal dose of MDR Aeromonas hydrophila. The results indicated no behavioral abnormalities or mortality of Nile tilapia during the 14 day study using the MRS-NB-O3 system. In the immersion challenge, although high bacterial concentration (~2 x 107 CFU/mL) was used, multiple NB-O3 treatments in the first two days reduced the bacteria between 15.9% to 35.6% of bacterial load in water while bacterial concentration increased 13.1% to 27.9% in the untreated control. There was slight up-regulation of non-specific immune-related genes in the gills of the fish receiving NB-O3 treatments. Most importantly, this treatment significantly improved survivability of Nile tilapia with relative percent survival (RPS) of 64.7 - 66.7% in treated fish and surviving fish developed specific antibody against MDR A. hydrophila. In summary, the result suggests that NB-O3 is a promising alternative to antibiotics to control bacterial diseases, including MDR bacteria, and has high potential for application in recirculation aquaculture system (RAS). HighlightsO_LIMultiple treatments of NB-O3 in a modified recirculation system (MRS) were relatively safe for juvenile Nile tilapia C_LIO_LINB-O3 treatments in MRS significantly improved survivability of Nile tilapia challenged with multidrug-resistant (MDR) A. hydrophila with RPS of 64.7 - 66.7% C_LIO_LIConcentration of MDR A. hydrophila in MRS was reduced by 15.9 to 35.6% following each NB-O3 treatment, and increased by 13.1 to 27.9 % in untreated control C_LIO_LISurviving fish developed specific antibody IgM against MDR A. hydrophila C_LIO_LINB-O3 is a promising non-antibiotic approach to control diseases caused by MDR A. hydrophila C_LI

microbiology↗

bioRxiv2021

Dissecting the localization of Tilapia tilapinevirus in the brain of the experimentally infected Nile tilapia (Oreochromis niloticus)

Tilapia tilapinevirus or tilapia lake virus (TiLV) is an emerging virus that inflicts significant mortality on farmed tilapia globally. Previous studies reported detection of the virus in multiple organs of the infected fish; however, little is known about the in-depth localization of the virus in the central nervous system. Herein, we determined the distribution of TiLV in the entire brain of experimentally infected Nile tilapia. In situ hybridization (ISH) using TiLV-specific probes revealed that the virus was broadly distributed throughout the brain. The strongest positive signals were dominantly detected in the forebrain (responsible for learning, appetitive behavior, and attention) and the hindbrain (involved in controlling locomotion and basal physiology). The permissive cell zones for viral infection were observed mostly to be along the blood vessels and the ventricles. This indicates that the virus may productively enter into the brain through the circulatory system and widen broad regions, possibly through the cerebrospinal fluid along the ventricles, and subsequently induce the brain dysfunction. Understanding the pattern of viral localization in the brain may help elucidate the neurological disorders of the diseased fish. This study revealed the distribution of TiLV in the whole infected brain, providing new insights into fish-virus interactions and neuropathogenesis.

pathology↗

bioRxiv2020

Ozone nanobubble treatment effectively reduced pathogenic Gram positive and negative bacteria in freshwater and safe for tilapia

High concentrations of pathogenic bacteria in water usually results in outbreaks of bacterial diseases in farmed fish. Here, we explored the potential application of an emerging nanobubble technology in freshwater aquaculture. Specifically, we aimed to determine if this technology was effective at reducing the concentration of pathogenic bacteria in the water, and to assess whether it was safe for fish. An ozone nanobubble (NB-O3) treatment protocol was established based on examination of nanobubble size, concentration, disinfection property, and impact on fish health. A 10-min treatment with NB-O3 in 50 L water generated approximately 2-3 x 107 bubbles with majority sizes less than 130 nm and ozone level of [~]800 mV ORP. A single treatment with water contaminated with either Streptococcus agalactiae or Aeromonas veronii effectively reduced 96.11-97.92 % of the bacterial load. This same protocol was repeated 3 times with 99.93-99.99 % reduction in the bacterial concentration. In comparison, bacterial concentration the control tanks remained the same level during the experiments. In fish-cultured water with the presence of organic matter (e.g. mucus, feces, bacterial flora, feed, etc.), the disinfection property of NB-O3 was reduced i.e bacterial concentration was reduced by 42.94 %, 84.94 % and 99.27 % after the first, second and third treatments, respectively. To evaluate the safety of NB-O3 to fish, juvenile Nile tilapia were exposed to NB-O3 treatment for 10 minutes. No mortality was observed during the treatment or 48 h post treatment. Gill histology examination revealed that a single NB-O3 treatment caused no alteration morphology. However, damage in the gill filaments was noticed in the fish receiving two or three consecutive exposures within the same day. Results of all the experiments conducted in this study suggest that NB-O3 technology is promising for controlling pathogenic bacteria in aquaculture systems, and may be useful at reducing the risk of bacterial disease outbreaks in farmed fish.

microbiology↗