Effects of ammonia and nitrite accumulation on the survival and growth performance of white shrimp Litopenaeus vannamei

ISJ 14: 221-232, 2017 ISSN 1824-307XRESEARCH REPORTAmmonia and nitrite levels caused by shrimp excreta and metabolic waste and organic detritus areimportant limiting factors in intensive aquaculture system, the purpose of this study was to determinehow ammonia and nitrite accumulation caused by accumulated these compounds affected survival andgrowth performance of white shrimp Litopenaeus vannamei. Unconsumed feed, feces and seawater intreatment group were not removed or replaced over a 33-day period, while unconsumed feed and fecesin control group were removed with a siphon tube and 60 % seawater was replaced once-daily.Significantly higher ammonia and nitrite concentrations were accumulated in the seawater of treatmentgroup from day 6 to day 33 and from day 9 to day 33, compared with control group, respectively.Significantly lower survival rate, weight gain percentage, length gain percentage and specific growthrate were recorded in treatment shrimp, compared with control shrimp. Significantly higher lipase,superoxide dismutase, and catalase activities, malondialdehyde content, relative expression of4E-binding protein 1, p70S6 kinase, glutamic-oxaloacetic transaminase and glutamic-pyruvictransaminase mRNA were detected in the hepatopancreas of treatment versus control shrimp.Significantly lower protease, glutathione reductase and glutathione peroxidase activities, andglutathione content were detected in the hepatopancreas of treatment versus control shrimp.Meanwhile, hepatopancreas in treatment shrimp showed disorganized tubules, blurred boundaries,decreased or disappeared B, R and E cells, injured connective tissue between liver tubule, infiltratedhemocytes, narrowed lumen, and vacuolization compared with control shrimp. These findings mightindicate that ammonia and nitrite accumulation caused by accumulated waste in aquaculture tankscould significantly reduce survival, growth performance of L. vannamei with hepatopancreas damage,which was resulted from accumulated reactive oxygen species. Therefore, ammonia and nitriteaccumulation may significantly impact shrimp production in intensive aquaculture system.