Acute effects of ammonia exposure on the plasma and haematological parameters and histological structure of the juvenile blunt snout bream,Megalobrama amblycephala,and post‐exposure recovery |
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| Authors: | Wuxiao Zhang Shengming Sun Xianping Ge Silei Xia Jian Zhu Linghong Miao Yan Lin Hualiang Liang Wenjing Pan Yanli Su Han Yu |
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| Affiliation: | 1. Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, China;2. Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, China |
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| Abstract: | In this study, we investigated the toxic effects of ammonia‐N on the plasma and haematological parameters and histological structure of blunt snout bream (Megalobrama amblycephala) juveniles. The fish (initial weight, 14.79 ± 0.01 g) were randomly sorted into six tanks (200 L), and each tank was stocked with 40 fish for culture. The juveniles were exposed to two ammonia‐N levels—0 mg/L (control group) and 25 mg/L (experimental group)—and sampled at 0, 6, 12, 24, 48 and 72 hr, and then they underwent 96 hr of post‐exposure recovery. The results showed that ammonia‐N had significant effects on the plasma and haematological parameters. The treatment group showed increased cortisol, plasma ammonia and haematocrit levels and white blood cell count with increasing exposure time, up to 24 hr, and then the levels and count decreased. A significantly higher plasma glucose level was observed in the treatment group at 12 hr. After 96 hr of post‐exposure recovery, all parameter levels decreased to the control levels. The fish displayed histopathological alterations in the gills, liver and kidney. The results indicate that the severity of the lesions clearly differed among the organs, with the liver showing the most extensive damage, followed by the gills and kidney. Adverse effects to physiological indicators and histological structure increased with increasing exposure time before 24 hr. The fish showed self‐regulation; however, the histological structure could not recover fully, the gill tissue showed irreversible changes and the kidney tissue exhibited the worst recovery ability. |
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| Keywords: | ammonia histological structure
Megalobrama amblycephala
plasma |
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