scholarly journals Effects of Chronic Hypoxia on the Immune Status of Pikeperch (Sander lucioperca Linnaeus, 1758)

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 649
Author(s):  
Nadine Schäfer ◽  
Jan Matoušek ◽  
Alexander Rebl ◽  
Vlastimil Stejskal ◽  
Ronald M. Brunner ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Stress Responses ◽  
Flow Cytometric Analysis ◽  
Head Kidney ◽  
Low Oxygen ◽  
Stress Genes ◽  
Recirculating Aquaculture ◽  
Recirculating Aquaculture Systems ◽  
Intensive Aquaculture ◽  
Low Do

Inadequate oxygen saturation can induce stress responses in fish and further affect their immunity. Pikeperch, recently introduced in intensive aquaculture, is suggested to be reared at nearly 100% DO (dissolved oxygen), yet this recommendation can be compromised by several factors including the water temperature, stocking densities or low circulation. Herein, we aimed to investigate the effect of low oxygen saturation of 40% DO (±3.2 mg/L) over 28 days on pikeperch farmed in recirculating aquaculture systems. The obtained data suggest that—although the standard blood and health parameters did not reveal any significant differences at any timepoint—the flow cytometric analysis identified a slightly decreased proportion of lymphocytes in the HK (head kidney) of fish exposed to hypoxia. This has been complemented by marginally downregulated expression of investigated immune and stress genes in HK and liver (including FTH1, HIF1A and NR3C1). Additionally, in the model of acute peritoneal inflammation induced with inactivated Aeromonas hydrophila, we observed a striking dichotomy in the sensitivity to the low DO between innate and adaptive immunity. Thus, while the mobilization of myeloid cells from HK to blood, spleen and peritoneal cavity, underlined by changes in the expression of key proinflammatory cytokines (including MPO, IL1B and TNF) was not influenced by the low DO, hypoxia impaired the influx of lymphocytes to the peritoneal niche in the later phases of the immune reaction. Taken together, our data suggest high robustness of pikeperch towards the low oxygen saturation and further encourage its introduction to the intensive aquaculture systems.

scholarly journals EFFECT OF FOUR DIFFERENT PRETREATMENTS IN NITROGEN AND PHOSPHORUS FLOW AND MASS BALANCE IN EFFLUENTS OF A RECIRCULATING AQUACULTURE SYSTEM

2016 ◽  
Vol 31 (2) ◽  
pp. 21
Author(s):  
Juan P. González -Hermoso ◽  
Emilio Peña -Messina ◽  
Anselmo Miranda -Baeza ◽  
Luis R. Martínez -Córdoba ◽  
María T. Gutiérrez -Wing ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Mass Balance ◽  
Biological Degradation ◽  
Nitrogen And Phosphorus ◽  
Recirculating Aquaculture ◽  
P Content ◽  
Recirculating Aquaculture Systems ◽  
High Concentrations ◽  
Intensive Aquaculture ◽  
Phosphorus Flow

ABSTRACT. The effluents from intensive aquaculture operations such as recirculating aquaculture systems (RAS) have high concentrations of sludge that can become a source of pollution if they are not properly treated and disposed. Anaerobic digestion is commonly used for biological degradation of sludge. Pretreatments prior to anaerobic digestion can enhance sludge degradation and decrease nitrogen and phosphorus load through microbial activity. This study examines the effect of four different pretreatments (biological, chemical, mechanical and thermal) in the N and P fluxes and mass balance from a RAS effluent in a seven-month period at ambient temperature. Each month a 15-day experiment was performed. All pretreatments, except chemical, removed N (thermal 29.78%, biological 36.75%, control 42.25%, mechanical 49.46%, chemical -7.68%). All pretreatments produced phosphorus (chemical 1.96%, mechanical 16.07%, thermal 24.37%, biological 32.39%, control 58.50%). Our results showed that the mechanical pretreatment was the most effective in removing N. In contrast, none of the pretreatments reduced P content in the sludge.Efecto de cuatro pretratamientos en el flujo y balance del nitrógeno y el fósforo en efluentes de un sistema de recirculación acuícolaRESUMEN. Los efluentes de un tipo de cultivo intensivo como los Sistemas de Recirculación Acuícola (SRA) presentan altas concentraciones de lodos que pueden llegar a ser una fuente de contaminación si no son tratados y dispuestos apropiadamente. La digestión anaeróbica es usualmente empleada para llevar a cabo la degradación de los lodos. Los pretratamientos previos a la digestión anaeróbica pueden mejorar la degradación de los lodos, así como reducir la carga de nitrógeno y fósforo a través de la actividad microbiana. Este estudio examinó el efecto de cuatro pretratamientos (biológico, químico, mecánico y térmico) en el flujo y balance de masas de N y P de efluentes de un SRA durante un periodo de 7 meses a temperatura ambiente. En cada mes se llevó a cabo un experimento de 15 días. Todos los pretratamientos a excepción del químico, eliminaron nitrógeno (térmico 29.78%, biológico 36.75%, control 42.25%, mecánico 49.46%, químico -7.68%). Todos los pretratamientos produjeron fósforo (químico 1.96%, mecánico 16.07%, térmico 24.37%, biológico 32.39%, control 58.60%). Nuestros resultados indican que el pretratamiento mecánico fue el más efectivo para eliminar N. En contraste, ninguno de los pretratamientos redujo la concentración de fósforo. 

scholarly journals Effects of Stocking Density on Growth Performance and Stress Responses of Bester and Bester ♀ × Beluga ♂ Juveniles in Recirculating Aquaculture Systems

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2292
Author(s):  
Lorena Dediu ◽  
Angelica Docan ◽  
Mirela Crețu ◽  
Iulia Grecu ◽  
Alina Mogodan ◽  
...  
Keyword(s):  
Growth Performance ◽  
Stress Responses ◽  
Stocking Density ◽  
Serum Cortisol ◽  
Lower Serum ◽  
Serum Parameters ◽  
Hematological Indices ◽  
Recirculating Aquaculture ◽  
Crowding Stress ◽  
Recirculating Aquaculture Systems

The study aimed to compare the growth performance and physiological responses of bester (B) and backcrossed bester ♀ × beluga ♂ (BB) in response to crowding stress under different stocking densities, as well as to establish a threshold stocking density for rearing BB in a recirculating aquaculture system (RAS) without welfare impairment. For this purpose, in the first trial (T1), B (181.15 ± 21.21 g) and BB fingerlings (181.98 ± 28.65 g) were reared in two stocking densities of 2 kg/m2 and 4 kg/m2 in fiberglass tanks (1 m3) for 6 weeks. In a parallel trial (T2), the BB hybrids (335.24 ± 39.30 g) were kept in four initial stocking densities, ranging from 5 kg/m2 to 12 kg/m2. The results of T1 revealed better growth indices (i.e., final mean weight, weight gain, specific growth rate) at lower stocking densities for both hybrids; however, in terms of growth performance, the BB hybrid showed better results when compared with the B hybrid. BB hybrids registered significantly (p < 0.05) lower serum cortisol and MDA and higher lysozyme than B hybrids, showing higher tolerance to crowding stress. Nevertheless, at higher densities, selected serum parameters (i.e., hematological indices, cortisol, glucose, protein, malondialdehyde, lysozyme) and growth performance indices used to evaluate the hybrids indicate that high stocking density could affect the growth and welfare of BB hybrids, and that the selected serum parameters could be used as good indicators for chronic stress caused by overcrowding conditions.

scholarly journals Breathing space: deoxygenation of aquatic environments can drive differential ecological impacts across biological invasion stages

2021 ◽  
Author(s):  
James W. E. Dickey ◽  
Neil E. Coughlan ◽  
Jaimie T. A. Dick ◽  
Vincent Médoc ◽  
Monica McCard ◽  
...  
Keyword(s):  
Climate Change ◽  
Oxygen Saturation ◽  
Ecological Impacts ◽  
Neogobius Melanostomus ◽  
Aquatic Environments ◽  
Relative Impact ◽  
Low Oxygen ◽  
Per Capita ◽  
The Impact ◽  
Prey Populations

AbstractThe influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species’ impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages.

scholarly journals Anaerobic Mineralization of Recirculating Aquaculture Drum Screen Effluent for Use as a Naturally-Derived Nutrient Solution in Hydroponic Cropping Systems

Conservation ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 151-167
Author(s):  
Joseph Tetreault ◽  
Rachel Fogle ◽  
Todd Guerdat
Keyword(s):  
Nutrient Solution ◽  
Agricultural Waste ◽  
The United States ◽  
Anaerobic Treatment ◽  
Production Costs ◽  
Effluent Treatment ◽  
Limiting Factors ◽  
Fertilizer Treatment ◽  
Recirculating Aquaculture ◽  
Recirculating Aquaculture Systems

Operation and effluent treatment costs are limiting factors for the success of recirculating aquaculture systems (RAS) in meeting seafood demand in the United States. Adopting a capture-and-reuse waste management model similar to terrestrial agriculture farmers would allow RAS farmers to monetize effluent and offset production costs. The moisture content and nutrient profile of RAS effluent makes it a potential option for use as a hydroponic fertilizer. Treatment of RAS waste is needed to mineralize particulate-bound nutrients before becoming a viable hydroponic nutrient solution. Anaerobic treatment (AT), a method used by municipal and agricultural waste treatment facilities to reduce total solids, has been shown to successfully mineralize particulate-bound nutrients from RAS effluent. Continuously mixed anaerobic batch bioreactors were used to evaluate the degree to which AT may mineralize particulate-bound nutrients in solid RAS waste. Concentrations of twelve different macro- and micro-nutrients were analyzed in the waste before and after treatment. Effluent samples were analyzed to determine the fraction of each nutrient in the solid and aqueous forms. This study showed that AT is an effective method to mineralize particulate-bound nutrients in RAS effluent and the mineralization rate data may be used to design a pilot-scaled flow-through RAS effluent treatment system.

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