Resistance of pearlspot larvae,Etroplus suratensis,to redspotted grouper nervous necrosis virus by immersion challenge     

Makesh Marappan  Aathithya Rengarajan  Venkata Satyanarayana Nallala  Krishna Sukumaran  Aritra Bera  Thirugnamurty Sivaramakrishnan  Govindarajan Thiagarajan  Muniyandi Kailasam  Vijayan Koyadan Kizhakedath 《Journal of fish diseases》2019,42(2):249-256

Viral nervous necrosis (VNN) affects more than 120 species mostly belonging to the order Perciformes. However, none of the brackishwater species belonging to the family Cichlidae under the order Perciformes are reported to be susceptible. Hence, the present experiment was undertaken to study the susceptibility of the brackishwater cichlid, pearlspot, Etroplus suratensis to NNV. Thirty‐day‐old pearlspot larvae were infected with NNV by immersion. Mortality was recorded till 14 days post‐infection, and the infected larvae were subjected to nested RT‐PCR and histology. The virus was isolated from infected larvae using SSN‐1 cells. To study the replication of the virus in vitro, primary cultured brain cells of E. suratensis and IEK cells were infected with NNV. No mortality was observed in any of the control or experimentally infected larvae. However, the experimentally infected larvae were positive for NNV by nested RT‐PCR and the virus was isolated using SSN‐1 cells. Further, the infected pearlspot brain cells and IEK cells showed cytopathic effect at second and third passage of the virus and they were positive for NNV by nested RT‐PCR. Pearlspot is relatively resistant to VNN although the virus could replicate in the larvae and in cell culture.  相似文献   

Effects of Diet and Organic Fertilization on Water Quality and Benthic Macroinvertebrate Populations in Ponds Used to Culture Freshwater Prawn,Macrobrachium rosenbergii     

《Journal Of Applied Aquaculture》2013,25(3):19-32

ABSTRACT

Effects of three diets: (1) complete diet; (2) supplemental diet (vitamin and mineral supplements not added); and (3) the supplemental diet with an adjunct organic fertilization regimen (using distiller's dried grains with solubles [DDGS]) on benthic macroinvertebrate populations and water quality in experimental ponds used to culture freshwater prawns, Macrobrachium rosenbergii were investigated. Benthic samples were taken from deep (1.5 m) and shallow (1.0 m) areas of each of nine 0.02-ha ponds every three weeks, using a 0.09-m² Ekman dredge. The abundance of gastro-pods, oligochaetes, total non-insects, chironomids, total dipterans, total insects, and total macroinvertebrates was significantly higher (P <0.05) in ponds receiving the complete diet, possibly due to lower predatory pressure by prawns or direct benefits of micronutri-ents. Total macroinvertebrate abundance was significantly decreased (P <0.05) in ponds receiving supplemental diet (with and without organic fertilization), possibly due to increased predation by prawns to supplement the nutrition not provided by the lower quality diet. Organic fertilization significantly increased (P <0.05) the abundance of oligochaetes and total macroinvertebrates. These data suggest that M. rosenbergii can adjust to reduced feed quality by increasing consumption of benthic fauna.  相似文献