Título:	Aeration strategy in the intensive culture of tambaqui, Colossoma macropomum, in the tropics
Autor:	Izel-Silva, Judá Ono, Eduardo Akifumi Queiroz, Marieta Nascimento de Santos, Raphael Brito dos
Palavras-chave:	Growth performance Hypoxia Artificial aeration Tambaqui
Data do documento:	2020
Revista:	Aquaculture
É parte de:	Volume 529, Número 735644
Resumo:	As the demand for fish increases and limitations are placed on water use, intensification in closed aquaculture systems could help to increase its sustainable production. The Amazon region stands out for its stable warm climate with fast-growing and resilient fish. This study evaluated the efficacy of two aeration regimes on intensive rearing of tambaqui, Colossoma macropomum, in six 46.4-m3 concrete-wall earthen bottom ponds, with no water exchange. Two aeration regimes were tested: (1) emergency aeration (EA), in which the aeration system was activated with dissolved oxygen (DO) levels below 3 mg L−1; (2) supplemental aeration (SA), with 8 h of aeration every night, and also during days with low solar radiation. Water quality, fish performance and health (haematological and parasitological indicators), aeration use and cost were assessed. Juveniles (44.39 ± 9.72 g, mean weight ± SD) were stocked in six concrete-wall ponds with earthen bottoms at 32,300 ha −1 and fed commercial feed (36–32% crude protein) for 17 weeks (122 days). Mean values of the water quality parameters showed no difference between treatments, but occurrences of hypoxia were significantly higher in SA (31 hypoxias with DO <2 mg L−1 and 11 extreme hypoxias with DO <0.5 mg L−1) than in EA (5 and 0.6 occurrences, respectively). Significantly more erythrocytes were observed in the fish in SA than in EA, which indicates a response to a low DO concentration. The parasitological analyses revealed 100% prevalence of Monogenoidea (Dactylogyridae) in animal gills, with higher abundance in the SA fish. All treatments showed high fish survival rate (99.6 ± 0.8% for EA; 99.3 ± 1.2% for SA) and low FCR (1.22 ± 0.1 for EA; 1.32 ± 0.1 for SA), but weight gain, specific growth rate and yield were higher (p <.05) and water use and energy cost was lower (p <.05) for EA. In conclusion, the aeration strategy influenced hypoxia frequency and aeration cost, resulting in superior fish performance and health conditions and lower energy cost in EA, which suggests this strategy to be more beneficial for tambaqui production than SA. © 2020
DOI:	10.1016/j.aquaculture.2020.735644
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