RESUMO

This study aimed to evaluate the effect of the biofloc technology (BFT) system and the replacement of fish meal with Spirulina biomass on productive performance, intestinal histomorphometry, plasma biochemistry, and oxidative stress of Nile tilapia juveniles (Oreochromis niloticus) fed suboptimal levels of protein. Two factors were evaluated: production systems (clear water × BFT) and replacement of fish meal with Spirulina (0, 33, 66 e 100%). The design was in a 2 × 4 randomized factorial scheme with four replications, and the fish were evaluated for 48 days. Four isoproteic (28% crude protein) diets were formulated with gross energy values close to 4300 kcal kg-1. Nile tilapia juveniles (0.23 ± 0.01 g) were distributed in 16 circular tanks (70 L) at seven fish/tank. The diets were formulated with protein levels approximately 20% below that required for the species and life stage. No interaction was observed between the factors evaluated (production systems × Spirulina inclusion). Rearing the fish in the BFT system avoided the adverse effects of diets with suboptimal protein levels on performance, intestinal histomorphometry, and protein metabolism. Lower values lower lipid peroxidation and higher antioxidant capacity were observed in fish reared in the BFT system, showing evidence of improvements in antioxidant responses and lower levels of physiological oxidative stress. Spirulina completely replaced fish meal in the diets of Nile tilapia juveniles without adverse effects on intestinal morphometry, protein metabolism, and antioxidant response. Replacing 66% of fish meal with Spirulina improved the productive performance, regardless of the rearing system.

Assuntos

RESUMO

The abundance of microplastics (MPs) in the gastrointestinal tract (GT), gills (GI), and exoskeleton (EX) of Litopenaeus vannamei shrimp cultured in a commercial indoor super-intensive controlled (ISCO) system was investigated. Shrimp of 25 days (postlarvae; PL25), and one, three, five, and seven culture months were analyzed. The postlarvae PL25 MP abundance per individual and gram of PL (wet weight) was 0.2 ± 0.0 MPs and 3.5 ± 0.5 MPs/g. For L. vannamei juveniles at one, three, five, and seven culture months, the MP abundance per juvenile shrimp was 10.0 ± 0.3, 27.2 ± 1.6, 32.3 ± 3.1, and 40.3 ± 3.6 MPs/individual, respectively (expressed in MPs/g of tissue were 1.6 ± 0.1, 2.0 ± 0.2, 2.0 ± 0.3 and 1.5 ± 0.2, respectively). Fibers were the most common MP type in all shrimp age classes (42.1-68.7 %), and the predominant color was transparent (46.1-65.0 %). The MP size in all shrimp stages ranged between 15 and 4686 µm. In general, the predominant polymers identified were PE (37.4 %), NY (21.1 %), and PET (18.5 %). The MP variability through the culture cycle showed that as the age of shrimp increased, and the culture advanced the MP abundance and size also augmented. Conversely, there is a higher MP abundance in L. vannamei cultured in ISCO systems compared to shrimp cultured in traditional semi-intensive and intensive ponds and those from wild environments. The latter is probably due to the extensive use of plasticized materials (geomembrane and greenhouse installations) and their degradation, which cause a greater MP exposure to shrimp. The estimated oral MP intake by ISCO shrimp consumption was 647 MPs/capita/year, which can be 178 % more than from wild shrimp.

Assuntos

RESUMO

European eel (Anguilla anguilla) elvers (initial body weight (BW) = 3 g) were raised in triplicate for 60 days in a biofloc system (BFT) at 21 °C. Data from the current first study evaluating this farming technology indicated that European eel elvers adapted well to BFT systems as data on growth performance (specific growth rate = 1.48% ± 0.13 BW/day and FCR = 1.05 ± 0.09) indicated, with production costs using BFT being lower than conventional RAS units. The most critical issues associated with this aquaculture system were the maintenance of the biofloc in tanks by the regular addition of refined sugar (46% C) to keep a relationship for C:N of 20:1, and the prevention of emergence of opportunistic pathogens like the monogenean Pseudodactylogyrus sp. The overall results of this study in terms of elvers' performance and quality and the composition of the biofloc material and its microbial composition indicated that BFT, which is considered to be one of the most cost-effective, sustainable, and environmentally friendly farming systems due to its zero water exchange and improvement of feed conversion ratio by the dietary contribution of bioflocs, may be satisfactorily used for farming European eels elvers at a density of 2 kg/m3. However, further studies are needed to test this technology with older eel stages.

RESUMO

Abstract Biofloc technology is much highlighted these days because of its tremendous effects on aquaculture. Microbes were enriched on cheapest organic carbon source i. e., powdered banana peels and were incorporated in different aquaria rearing grass carp fingerlings under different C/N treatments (10:1, 15:1 and 20:1) and 10% water daily water exchange. The initial growth of fingerlings was recorded. The experiment was settled in triplicates for 60 days and run parallel to control group provided with commercial feed and daily water exchange. Its effect was evaluated by measuring the growth of fingerlings and water parameters of each aquarium. The average % gain in weight and length of fingerlings was obtained significantly highest (28.12 ± 0.30g and 17.29 ± 0.46cm respectively) in aquaria containing pure powdered banana peels with 10% water exchange and C/N ratio was adjusted at 20: 1 (T3) than other treatments and control. Ammonia and other water parameters were also under control in T3 than other experimental and control groups. By all counts, it was concluded that the highest C/N ratio in biofloc system had the potential to increment C. idella growth rate by reducing toxicity and could be used as fish meal substitute.

Resumo A tecnologia Biofloc é muito destacada hoje em dia por causa de seus tremendos efeitos na aquicultura. Os micróbios foram enriquecidos com a fonte de carbono orgânico mais barata, i. e., cascas de banana em pó, e foram incorporadas em diferentes aquários de criação de alevinos de carpa-capim sob diferentes tratamentos C/N (10: 1, 15: 1 e 20: 1) e 10% de troca diária de água. O crescimento inicial dos alevinos foi registrado. O experimento foi resolvido em triplicatas por 60 dias e executado paralelamente ao grupo controle fornecido com ração comercial e troca diária de água. Seu efeito foi avaliado medindo o crescimento dos alevinos e os parâmetros da água de cada aquário. O% de ganho médio em peso e comprimento dos alevinos foi obtido significativamente mais alto (28,12 ± 0,30g e 17,29 ± 0,46 cm respectivamente) em aquários contendo cascas de banana em pó puro com 10% de troca de água e a relação C/N foi ajustada em 20: 1 (T3) do que outros tratamentos e controle. A amônia e outros parâmetros da água também estavam sob controle no T3 mais do que nos outros grupos experimentais e de controle. Por todas as contagens, concluiu-se que a maior razão C/N no sistema de bioflocos tem o potencial de incrementar a taxa de crescimento de C. idella reduzindo a toxicidade e pode ser usada como substituto da farinha de peixe.

RESUMO

Biofloc technology is much highlighted these days because of its tremendous effects on aquaculture. Microbes were enriched on cheapest organic carbon source i. e., powdered banana peels and were incorporated in different aquaria rearing grass carp fingerlings under different C/N treatments (10:1, 15:1 and 20:1) and 10% water daily water exchange. The initial growth of fingerlings was recorded. The experiment was settled in triplicates for 60 days and run parallel to control group provided with commercial feed and daily water exchange. Its effect was evaluated by measuring the growth of fingerlings and water parameters of each aquarium. The average % gain in weight and length of fingerlings was obtained significantly highest (28.12 ± 0.30g and 17.29 ± 0.46cm respectively) in aquaria containing pure powdered banana peels with 10% water exchange and C/N ratio was adjusted at 20: 1 (T3) than other treatments and control. Ammonia and other water parameters were also under control in T3 than other experimental and control groups. By all counts, it was concluded that the highest C/N ratio in biofloc system had the potential to increment C. idella growth rate by reducing toxicity and could be used as fish meal substitute.(AU)

A tecnologia Biofloc é muito destacada hoje em dia por causa de seus tremendos efeitos na aquicultura. Os micróbios foram enriquecidos com a fonte de carbono orgânico mais barata, i. e., cascas de banana em pó, e foram incorporadas em diferentes aquários de criação de alevinos de carpa-capim sob diferentes tratamentos C/N (10: 1, 15: 1 e 20: 1) e 10% de troca diária de água. O crescimento inicial dos alevinos foi registrado. O experimento foi resolvido em triplicatas por 60 dias e executado paralelamente ao grupo controle fornecido com ração comercial e troca diária de água. Seu efeito foi avaliado medindo o crescimento dos alevinos e os parâmetros da água de cada aquário. O% de ganho médio em peso e comprimento dos alevinos foi obtido significativamente mais alto (28,12 ± 0,30g e 17,29 ± 0,46 cm respectivamente) em aquários contendo cascas de banana em pó puro com 10% de troca de água e a relação C/N foi ajustada em 20: 1 (T3) do que outros tratamentos e controle. A amônia e outros parâmetros da água também estavam sob controle no T3 mais do que nos outros grupos experimentais e de controle. Por todas as contagens, concluiu-se que a maior razão C/N no sistema de bioflocos tem o potencial de incrementar a taxa de crescimento de C. idella reduzindo a toxicidade e pode ser usada como substituto da farinha de peixe.(AU)

Assuntos

RESUMO

Biofloc technology is much highlighted these days because of its tremendous effects on aquaculture. Microbes were enriched on cheapest organic carbon source i. e., powdered banana peels and were incorporated in different aquaria rearing grass carp fingerlings under different C/N treatments (10:1, 15:1 and 20:1) and 10% water daily water exchange. The initial growth of fingerlings was recorded. The experiment was settled in triplicates for 60 days and run parallel to control group provided with commercial feed and daily water exchange. Its effect was evaluated by measuring the growth of fingerlings and water parameters of each aquarium. The average % gain in weight and length of fingerlings was obtained significantly highest (28.12 ± 0.30g and 17.29 ± 0.46cm respectively) in aquaria containing pure powdered banana peels with 10% water exchange and C/N ratio was adjusted at 20: 1 (T3) than other treatments and control. Ammonia and other water parameters were also under control in T3 than other experimental and control groups. By all counts, it was concluded that the highest C/N ratio in biofloc system had the potential to increment C. idella growth rate by reducing toxicity and could be used as fish meal substitute.

A tecnologia Biofloc é muito destacada hoje em dia por causa de seus tremendos efeitos na aquicultura. Os micróbios foram enriquecidos com a fonte de carbono orgânico mais barata, i. e., cascas de banana em pó, e foram incorporadas em diferentes aquários de criação de alevinos de carpa-capim sob diferentes tratamentos C/N (10: 1, 15: 1 e 20: 1) e 10% de troca diária de água. O crescimento inicial dos alevinos foi registrado. O experimento foi resolvido em triplicatas por 60 dias e executado paralelamente ao grupo controle fornecido com ração comercial e troca diária de água. Seu efeito foi avaliado medindo o crescimento dos alevinos e os parâmetros da água de cada aquário. O% de ganho médio em peso e comprimento dos alevinos foi obtido significativamente mais alto (28,12 ± 0,30g e 17,29 ± 0,46 cm respectivamente) em aquários contendo cascas de banana em pó puro com 10% de troca de água e a relação C/N foi ajustada em 20: 1 (T3) do que outros tratamentos e controle. A amônia e outros parâmetros da água também estavam sob controle no T3 mais do que nos outros grupos experimentais e de controle. Por todas as contagens, concluiu-se que a maior razão C/N no sistema de bioflocos tem o potencial de incrementar a taxa de crescimento de C. idella reduzindo a toxicidade e pode ser usada como substituto da farinha de peixe.

Assuntos

RESUMO

The aim of this study was to evaluate the sensory quality of Pacific white shrimp (L. vannamei) fed diets in which fish meal was replaced by soy protein concentrate. Four diets were evaluated, with different levels of replacement (33%, 66% and 100%) of fish meal by soy protein concentrate. In the sensory analysis, 50 tasters evaluated using the ordering preference test and 50 tasters evaluated the acceptability of the shrimp. The inclusion of vegetable protein source in the shrimp diet sho-wed no difference in the discriminatory and preference ordering test and did not change the evaluated sensory attributes, which makes the product attractive to the consumer, due to the fact of consuming a product without presenting alterations in the taste(AU)

O objetivo deste estudo foi avaliar a qualidade sensorial do camarão-branco-do-pacífico (L. vannamei) alimentados com dietas em que houve substituição da farinha de peixe por concentrado proteico de soja. Quatro dietas foram avaliadas, com diferentes níveis de substituição (33%, 66% e 100%) da farinha de peixe pelo concentrado proteico de soja. Na análise sensorial, 30 provadores avaliaram por meio do teste de ordenação de preferência e 50 provadores avaliaram a aceitabilidade dos camarões. A inclusão da fonte proteica vegetal na dieta dos camarões não apresentou diferença no teste discriminatório e de ordenação de preferência e não alterou os atributos sensoriais avaliados, o que torna o produto atrativo para o consumidor, pelo fato de consumir um produto sem apresentar alterações no paladar.(AU)

Assuntos

RESUMO

This work compared biofloc technology and aquamimicry technologies in Litopenaeus vannamei lined ponds, using a density of 60 shrimp·m-2. The experiment lasted 120 days, with two treatments, bioflocs (TBio) and aquamimicry (TMi), and three replications for each. In both treatments, the average values of the water quality parameters were as follows: temperature was 24.0 ± 0.32 °C, dissolved oxygen was 8.00 ± 0.45 mg·L-1, pH was 8.40 ± 0.20, and alkalinity was 240.01 ± 37.15 mg·L-1. The control of water quality was effectively maintained in both treatments, indicating the aquamimicry system's capability to efficiently recycle the nutrients found in the lined ponds' water. Furthermore, both treatments demonstrated efficiency in shrimp production, and the shrimp from the TMi treatment reached an average final weight of 11.73 ± 2.21 g, average survival of 53.3 ± 15.2%, and productivity of 3.56 ± 0.15-ton·ha-1. The TBio shrimp reached a final weight of 11.48 ± 1.25 g, survival of 63.3 ± 8.16%, and productivity of 4.08 ± 1.10-ton·ha-1. The present study demonstrated that TMi treatment ponds presented zootechnical performances close to those of TBio treatment ponds. The results achieved can contribute to the improvement of this cultivation system to use it in higher stocking densities.(AU)

Este trabalho comparou as tecnologias sistema de bioflocos e aquamimicry em viveiros revestidos de Litopenaeus vannamei,usando densidade de 60 camarões·m-2. O experimento teve duração de 120 dias e envolveu dois tratamentos, bioflocos (TBio) e aquamimicry (TMi), e três repetições para cada um. Em ambos os tratamentos, os valores médios dos parâmetros de qualidade da água foram os seguintes: temperatura = 24,0 ± 0,32 °C, oxigênio dissolvido = 8,00 ± 0,45 mg·L-1, pH = 8,40 ± 0,20, e alcalinidade = 240,01 ± 37,15 mg·L- 1. O controle da qualidade da água foi efetivamente mantido em ambos os tratamentos, indicando a capacidade do sistema aquamimicry de reciclar eficientemente os nutrientes encontrados na água dos tanques revestidos. Além disso, ambos os tratamentos demonstraram eficiência na produção de camarões. Os camarões procedentes do tratamento TMi atingiram peso final médio de 11,73 ± 2,21 g, sobrevivência média de 53,3 ± 15,2% e produtividade de 3,56 ± 0,15 ton·ha-1. Os camarões do TBio alcançaram peso final de 11,48 ± 1,25 g, sobrevivência de 63,3 ± 8,16% e produtividade de 4,08 ± 1,10 ton·ha-1. O presente estudo demonstrou que viveiros do tratamento TMi apresentaram desempenhos zootécnicos próximos aos dos viveiros do tratamento TBio. Os resultados alcançados podem contribuir para o aprimoramento desse sistema de cultivo com o objetivo de utilizá-lo em densidades de estocagens mais elevadas.(AU)

Assuntos

RESUMO

RESUMEN El objetivo de esta investigación fue establecer el biofloc a tres relaciones carbono/ nitrógeno (C/N): 10/1, 15/1 y 20/1, determinando la secuencia de remoción de N, el perfil de sólidos y la caracterización del zooplancton, para tal fin se dispuso de tres tanques con volumen de 7000 L, incorporando oxígeno al agua a través de un aireador tipo soplador. Se utilizó como fuente de N balanceado, fuente de carbono melaza y bicarbonato de sodio como fuente alcalinizante. Al inicio se incrementó el nitrógeno amoniacal total NAT a 2 mg/L, la alcalinidad total (AT) a 120 mg/L y se adicionó como inóculo 10 litros/tanque de agua proveniente de un estanque de cultivo, al sexto y décimo días se adicionó balanceado incrementando teóricamente el NAT en 4 mg/L y a partir del día 12 en 1 mg/L. En las tres relaciones C/N se evidenciaron procesos de nitrificación durante la estabilización del biofloc, hasta llegar en el tiempo a concentraciones no letales de amonio y nitrito para peces, menores a 1 mg/L. En cuanto a los sólidos volátiles, se encontró una mayor concentración en la relación 20/1, lo cual puede atribuirse a la mayor adición de melaza, con la consecuente producción de SSV a partir de la dominancia de comunidades heterotróficas, en los tres macrocosmos se presentaron comunidades del zooplancton, no obstante, el T2 presentaron la mayor abundancia y riqueza de organismos. Las tres relaciones C/N en biofloc establecieron condiciones de calidad de agua y alimento vivo.

ABSTRACT The objective of this research was to establish the biofloc at three carbon/nitrogen (C/N) relationships: 10/1, 15/1 and 20/1, determining the N removal sequence, the solids profile and the characterization of the zooplankton, for this purpose three tanks with a volume of 7000 L were available, incorporating oxygen into the water through a blower-type aerator. It was used as a source of balanced N, a source of carbon molasses and sodium bicarbonate as an alkalizing source. At the beginning, the total ammoniacal nitrogen NAT was increased to 2 mg/L, the total alkalinity (AT) to 120 mg/L and 10 liters / tank of water from a culture pond was added as inoculum, on the sixth and tenth days it was he added balanced, theoretically increasing the NAT by 4 mg/L and from day 12 by 1 mg/L. In the three C / N relationships, nitrification processes were evidenced during the stabilization of the biofloc, until reaching non-lethal concentrations of ammonium and nitrite for fish, less than 1 mg/L in time. Regarding volatile solids, a higher concentration was found in the 20/1 ratio, which can be attributed to the greater addition of molasses, with the consequent production of SSV from the dominance of heterotrophic communities, in the three macrocosms there were Zooplankton communities, however, T2 presented the highest abundance and richness of organisms. The three C / N relationships in biofloc established conditions of water quality and live food.

RESUMO

In recent decades, new aquaculture technologies have been developed and improved, such as the Biofloc Technology system, which is considered an alternative to the conventional aquaculture model. This study compared the bioeconomic viability of intensive production in nurseries and super-intensive production of shrimp Litopenaeus vannamei bioflocs greenhouses. The investment for implementing the project was US$ 767,190.18 for intensive production and US$ 807,669.16 for super-intensive production. The analyses showed Net Present Value of US$ 363,718.21 and US$ 385,477.42, Equivalent annual value of US$ 59,830.66 and US$ 63,410.00, Net future value of US$ 965,052.69 and US$ 1,022,786.35, Payback Period 4.12 and 4.11, Discounted payback period 5.64 and 5.63, Profitability Index 1.47 and 1.48, Internal Rate of Return 20.49 and 20.55%, and Modified Internal Rate of Return 14.61 and 14.64%. The investment analysis used in this study showed that super-intensive production in a greenhouse is the best investment option. The development of a new scenario simulating the super-intensive production of shrimp in a Biofloc Technology system, considering land use as a premise, made it possible to observe the possibility of obtaining financial gains in scale, both in the reduction of production costs and in the economic performance of the enterprise. However, the financial contribution for the implementation and operation of the project increased substantially.

Nas últimas décadas, novas tecnologias aquícolas têm sido desenvolvidas e aprimoradas, como o sistema de bioflocos, considerado uma alternativa ao modelo convencional aquícola. O presente estudo compara a viabilidade bioeconômica da produção intensiva em viveiros com a da produção superintensiva em estufas do camarão Litopenaeus vannamei em bioflocos. O investimento para implantação do projeto foi de US$ 767.190,18 para produção intensiva e US$ 807.669,16 para superintensiva. As análises apresentaram valor presente líquido de US$ 363.718,21 e US$ 385.477,42, valor anual equivalente de US$ 59.830,66 e US$ 63.410,00, valor futuro líquido de US$ 965.052,69 e US$ 1.022.786,35, período de payback 4,12 e 4,11, payback descontado 5,64 e 5,63, índice de lucratividade 1,47 e 1,48, taxa interna de retorno 20,49 e 20,55% e taxa interna de retorno modificada 14,61 e 14,64%. As análises de investimentos neste estudo mostraram que a produção superintensiva em estufas é a melhor opção. O desenvolvimento de um novo cenário simulando a produção superintensiva de camarões em sistema de bioflocos, considerando o uso da terra como premissa, permitiu observar a possibilidade de ganhos financeiros em escala tanto na redução dos custos de produção quanto no desempenho econômico do empreendimento. No entanto, a contribuição financeira para implantar e operar o projeto aumentou substancialmente.

Assuntos

RESUMO

Finding new alternatives to traditional live preys such as Artemia and rotifers, which do not always promote optimal fish growth and survival, is required for the successful aquaculture of highly specialized predatory species, including seahorses. The present study assessed the nutritional value of an interesting marine amphipod (Parhyale hawaiensis), and evaluates through a feeding trial its potential use as a natural prey for 10-months lined seahorse, Hippocampus erectus. P. hawaiensis showed high levels of valuable lipids (20.4-26.7% on dry matter basis) and polyunsaturated fatty acids (PUFAs) ( 26.4-41% of total FAs), including the long-chain PUFAs (LC-PUFAs) arachidonic acid (ARA) (2.9-7.7%), eicosapentaenoic acid (EPA) (4.3-6.5%) and docosahexaenoic acid (DHA) (2.1-6.2%). A comparison between wild-captured and cultured amphipods revealed a significant improvement of the amphipod FA profile in terms of DHA%, total omega-3 (n3) FAs and n3/n6 ratio when employing both a conventional amphipod culture based on a commercial shrimp diet, and, to a lesser extent, a large (3,500 L) biofloc system. Seahorses fed with frozen/wild amphipods, either singly or in combination with Artemia enriched with Super Selco® (INVE Aquaculture, Belgium) for 57 days, substantially improved seahorse growth and FA profiles in terms of ARA, EPA and DHA%, including indices associated to marine sources, such as Σn3 and n3/n6, compared to a diet based solely on enriched Artemia. These results support the use of marine amphipods as an alternative food organism for juvenile H. erectus and suggest a potential use for general marine aquaculture.

RESUMO

Aquaculture production has increased in the last decades, with crustacean production contributing with 9.8% of the total production. However, fisheries and aquaculture sectors present several challenges, such as fish stocks fished beyond biological sustainability, animal diseases, biosecurity, and environmental impact. It is important to improve shrimp production with healthy animals, avoiding environmental impacts, e.g. with the use of heterotrophic rearing system. It is known that the heterotrophic system can stimulate the activation of immune genes, but how it affects the shrimp immune system is unknown. To assess if a heterotrophic system influences the cellular immune response in shrimp, Litopenaeus vannamei shrimp were reared in heterotrophic and clear water systems. Cellular immune response parameters such as total and differential hemocyte counts, phagocytosis indices and the production of the superoxide anion were evaluated after 60, 120 and 180 days. After 60 days, total haemocyte counts were higher in shrimps reared in the clear water system, while after 120 days it was higher in shrimps reared in the heterotrophic system. No significant difference was observed after 180 days. Hyaline, granular and semi-granular cells showed similar behavior, peaking after 120 days in the heterotrophic system. By the 60th day, phagocytic capacity was higher in the heterotrophic system, while no differences were found for the 120th and 180th day. No differences were detected concerning the phagocytic index or superoxide anion production. The heterotrophic system can affect total and differential shrimp haemocyte counts and phagocytic capacity, depending on the period of time they were maintained in this system. However, the phagocytic index and superoxide anion production are not affected by the heterotrophic system at the time points evaluated herein.

RESUMO

This study aims at investigating to follow the formation and development of biofloc aggregates in a system with the introduction of an in vitro selected bacterial consortium (Bacillus thuringiensis, Bacillus sp., Staphylococcus cohnii) in order to induce fast formation of biofloc and to compare it to the development of spontaneous formation biofloc. Two experimental groups were evaluated for biofloc formation, SFT and IFT. The first refers to spontaneous (conventional) formation of the flocs and the second to induced formation (IFT), achieved through the consortium of potentially inducing bacteria. Both treatments presented a constant increase of bioflocs, however, in the IFT treatment, the microbial aggregates were larger and more uniform. By the end of the experiment, we verified that the aggregates formed in the IFT showed higher volume and lower sedimentation rate in comparison to the spontaneously formed ones. The results show that domestication in microbial communities is efficient as related to bioflocs, reducing instability during its formation and development.

Assuntos

RESUMO

The current study aimed at fostering bacterial growth in BFT aquaculture tanks by early Nile tilapia stocking. Control tanks had no tilapia but received daily applications of dry molasses (NT+) or had tilapia but no C:N ratio adjustment (T-). Experimental tanks had tilapia and received daily application of molasses to adjust the C:N ratio of water to 15:1 (T+). The development of bioflocs in NT+ was insignificant as demonstrated by low levels of settleable solids (SS) and total suspended solids (TSS). Total ammonia nitrogen (TAN) was significantly higher in NT+ than in T+. In the C:N-ratio adjusted tanks, the presence of fish shortened the control of TAN in several days. As nitrite declined in T+, it increased in NT+. The final concentrations of TSS in T+, T- and NT+ were 236 ± 29 mg L-1, 100 ± 32 mg L-1, and 40 ± 22 mg L-1, respectively (p < 0.05). It can be concluded that stable nitrifying and heterotrophic bacterial communities could be attained in BFT aquaculture tanks, before the end of the 4th week of culture, if the bacterial growth is fostered by early Nile tilapia stocking.

Assuntos

RESUMO

This study aims at investigating to follow the formation and development of biofloc aggregates in a system with the introduction of an in vitro selected bacterial consortium (Bacillus thuringiensis, Bacillus sp., Staphylococcus cohnii) in order to induce fast formation of biofloc and to compare it to the development of spontaneous formation biofloc. Two experimental groups were evaluated for biofloc formation, SFT and IFT. The first refers to spontaneous (conventional) formation of the flocs and the second to induced formation (IFT), achieved through the consortium of potentially inducing bacteria. Both treatments presented a constant increase of bioflocs, however, in the IFT treatment, the microbial aggregates were larger and more uniform. By the end of the experiment, we verified that the aggregates formed in the IFT showed higher volume and lower sedimentation rate in comparison to the spontaneously formed ones. The results show that domestication in microbial communities is efficient as related to bioflocs, reducing instability during its formation and development.(AU)

Assuntos

RESUMO

The current study aimed at fostering bacterial growth in BFT aquaculture tanks by early Nile tilapia stocking. Control tanks had no tilapia but received daily applications of dry molasses (NT+) or had tilapia but no C:N ratio adjustment (T-). Experimental tanks had tilapia and received daily application of molasses to adjust the C:N ratio of water to 15:1 (T+). The development of bioflocs in NT+ was insignificant as demonstrated by low levels of settleable solids (SS) and total suspended solids (TSS). Total ammonia nitrogen (TAN) was significantly higher in NT+ than in T+. In the C:N-ratio adjusted tanks, the presence of fish shortened the control of TAN in several days. As nitrite declined in T+, it increased in NT+. The final concentrations of TSS in T+, T- and NT+ were 236 ± 29 mg L-1, 100 ± 32 mg L-1, and 40 ± 22 mg L-1, respectively (p < 0.05). It can be concluded that stable nitrifying and heterotrophic bacterial communities could be attained in BFT aquaculture tanks, before the end of the 4th week of culture, if the bacterial growth is fostered by early Nile tilapia stocking.(AU)

Assuntos

RESUMO

Abstract Background: Shrimp farming is evolving from semi-intensive to hyper-intensive systems with biofloc technology and water recirculation systems. Objective: To evaluate the transcriptional response promoted by biofloc on shrimp (Litopenaeus vannamei) under a recirculating aquaculture system (RAS). Methods: Quantitative real-time RT-PCR was used to monitor seven key genes related to the immune system in shrimp post-larvae, reared in a RAS with and without biofloc (BF and no- BF). In addition, we present for the first time nucleotide sequences of ADP-ribosylation factor 4 (LvArf4) from Litopenaeus vannamei. Results: Transcripts for penaeidin3 (Pen3), penaeidin4 (Pen4), crustin, and Toll receptor (LvToll) genes were up-regulated between 3 and 24 h in both systems, and tumor necrosis factor receptor-associated factor 6 (TRAF6) in no-BF as an early response. Regarding differential expression between treatments, 13 occurrences were encountered. Nine that were higher in BF than in no-BF and four higher in no-BF than in BF. In some sample times, expression of Pen3, crustin, LvToll, TRAF6, IMD, and LvArf4 was higher in BF than in no-BF and in others, expression of Pen3, Pen4, and TRAF6 was higher in no-BF than in BF. Conclusions: BF modulates the transcription of genes related to the immune response in shrimp as an early response. However, the RAS with no-BF promotes a similar response.

Resumen Antecedentes: Los cultivos de camarón están evolucionando de sistemas semi-intensivos a hiper-intensivos con biofloc y con recirculación. Objetivo: Evaluar la respuesta transcripcional promovida por el biofloc en un sistema acuícola con recirculación (SAR). Métodos: Monitoreamos mediante RT-PCR cuantitativo siete genes relacionados con el sistema inmune en postlarvas de camarón cultivadas en un SAR con y sin biofloc (BF y no-BF). Además, presentamos por primera vez la secuencia de nucleótidos del factor de ribosilación 4 de ADP (LvArf4) de Litopenaeus vannamei. Resultados: Los genes penaeidina3 (Pen3), penaeidina4 (Pen4), Crustina y Toll (LvToll) se sobre-expresaron entre las 3 y 24 h en ambos sistemas, y el factor 6 asociado al factor de necrosis tumoral (TRAF6) en BF como una respuesta temprana. Con respecto a la expresión diferencial entre los tratamientos, se presentaron 13 ocurrencias. Nueve donde el BF fue mayor que sin-BF y cuatro donde el no-BF fue mayor que el BF. La expresión fue más alta en BF que en no-BF en Pen3, Crustin, LvToll, TRAF6, IMD y LvArf4. En contraste, la expresión fue mayor en no-BF en Pen3, Pen4 y TRAF6. Conclusión: el BF modula la transcripción de los genes relacionados con la respuesta inmune en camarón como una respuesta temprana. Sin embargo, el SAR sin-BF promueve una respuesta similar.

Resumo Antecedentes: A criação de camarões está evoluindo de sistemas semi-intensivos para hiper-intensivos como tecnologia de bioflocos e sistemas de recirculação. Objetivo: Avaliar a resposta transcricional promovida pelo biofloco em um sistema de aquicultura recirculante (SAR). Métodos: Utilizamos RT-PCR quantitativo em tempo real para monitorar sete genes-chave relacionados ao sistema imune em pós-larvas de camarão, criados em SAR com e sem bioflocos (BF e no-BF). Além disso, apresentamos pela primeira vez sequências nucleotídicas do fator de ribosilação do ADP 4 (LvArf4) de Litopenaeus vannamei. Resultados: Os resultados mostraram que o Penaeidina3 (PEN3), Penaeidina4 (Pen4), Crustina e Toll genes (LvToll) foram sobre-expressos entre 3 e 24 h em ambos os sistemas, e o Factor de Necrose do Receptor 6 associado e protuberância (TRAF6) no BF como uma resposta precoce. Com relação à expressão diferencial entre tratamentos, 13 ocorrências foram apresentadas. Nove onde o BF foi maior do que os não-BF e quatro onde o não-BF foi maior do que o BF. A expressão foi maior do que em BF não-BF em Pen3, Crustin, LvToll, TRAF6, IMD e LvArf4. Em contraste, a expressão foi mais elevada no não-BF em Pen3, Pen4 e TRAF6. Conclusões: O BF modula a transcrição de resposta imune relacionada no camarão como um genes de resposta precoce. No entanto, o SAR não BF promove uma resposta semelhante.

RESUMO

The super-intensive BioFloc Technology (BFT) system has been highlighted as a promising eco-friendly alternative to the traditional shrimp rearing systems. To gain insight into the impact of environmental rearing conditions on shrimp intestinal immunity, we assessed the expression profile of key immunological genes in the midgut of Litopenaeus vannamei shrimp reared in two contrasting culture systems: the indoor super-intensive BFT and the outdoor intensive Green-Water System (GWS). From the 30 analyzed genes, the expression levels of 25 genes were higher in the midgut of shrimp reared in BFT than in GWS. The main functional categories represented in BFT-shrimp were the prophenoloxidase-activating system, immune signaling, antimicrobial peptides, and RNA interference pathway. Comparatively, only the RNAi pathway gene Dicer-1 (LvDcr1) was more expressed in animals from the GWS group. However, despite the differences in gene expression, the total midgut bacterial abundance was similar between the experimental groups. Altogether, our results suggest that the microbial-rich environment offered by the BFT system can be acting as an immunostimulant by altering the immune expression profile of the midgut. The gene expression level found in GWS animals could be related to the chronic presence of the IMNV in the Brazilian Northeast. Knowing the effects of environmental stress factors on the intestinal immune defenses can provide an in-depth understanding of the relationship between cultivated shrimp and the major pathogens affecting the shrimp industry.

Assuntos

RESUMO

The aim of this study was to evaluate the performance of Nile tilapia fingerlings cultured in biofloc technology using different inoculation densities of Chlorella vulgaris. The experimental design was completely randomized with biofloc system and four densities of Chlorella vulgaris (0, 2.5, 5 and 10 x 104 cell mL-1), each with four replications. The study lasted 63 days and was carried out in tanks with a working volume of 40L, at a stocking density of 10 fish per experimental unit and a mean initial weight of approximately 1.86 g. The water quality variables showed no significant difference between treatments, especially total ammonia nitrogen and nitrite nitrogen, which were within acceptable levels for culture of the species. The variables of zootechnical performance were not affected by the different inoculation densities of the microalgae, achieving a final mean weight of approximately 21 g for all treatments, and survival rates greater than 80%. The weekly inoculation densities of the microalgae Chlorella vulgaris therefore had no influence on the growth of tilapia fingerlings cultured in a biofloc system.

O presente trabalho teve como objetivo avaliar o desempenho de alevinos de tilápia do Nilo, cultivados em tecnologia de bioflocos, utilizando diferentes densidades de inoculação de Chlorella vulgaris. O delineamento experimental foi inteiramente casualizado, envolvendo o cultivo em sistema de bioflocos e quatro densidades de Chlorella vulgaris (0; 2,5; 5 e 10x104 cel mL-1), com quatro repetições cada. O trabalho teve duração de 63 dias, sendo realizado em caixas com 40L de volume útil, densidade de estocagem de 10 peixes por unidade experimental e peso médio inicial de aproximadamente 1,86 g. As variáveis de qualidade de água não apresentaram diferença significativa entre os tratamentos, principalmente o nitrogênio da amônia total e do nitrito, que estiveram dentro do nível aceitável para o cultivo da espécie. As variáveis de desempenho zootécnico não foram afetadas pelas diferentes densidades de inoculação da microalga, obtendo peso médio final de aproximadamente 21 g para os tratamentos e taxas de sobrevivência superiores a 80%. Portanto para estas densidades de inoculação da microalga Chlorella vulgaris, com frequência semanal, não apresentaram influência no crescimento de alevinos de tilápia cultivada com bioflocos.

Assuntos

RESUMO

The purpose of this study was to produce Daphnia magna in wastewater from Tilapia farmed in a biofloc system, to evaluate three different carbohydrate:nitrogen ratios. The experiment was conducted for 30 days following a completely randomized experimental design, with the three treatments: C:N 10:1, C:N 15:1 and C:N 20:1, all fed with Chlorella vulgaris. The physical-chemical variables of the water analyzed were: temperature, dissolved oxygen (DO), pH, TAN, NO2, hardness and alkalinity. The following growth variables of the Daphnia were also evaluated: Maximum average density (MAD), Maximum density day (MDD), Specific growth rate (SGR), Doubling time (DT) and yield (Y). The water quality variables remained in the range of ideal conditions for the species, presenting significant differences (p <0.05) among the treatments for: pH, DO, hardness and alkalinity. Regarding the growth variables, significant differences (p <0.05) were observed, with higher MAD, Y and SGR values for the 10:1 treatment (3,433 ± 267 ind L-1, 245 ± 19 ind L-1 day- 1 and 45.3 ± 0.6% day-1, respectively) and lower for the 20:1 (1,011 ± 283 ind L-1, 55 ± 15 ind L-1 day-1 and 28.3 ± 1.6% day-1, respectively). The MDD occurred on day 12 for the 10:1 treatment and on day 18 for the 15:1 and 20:1 treatments. Alkalinity and hardness had stronger influence on the growth variables, which was also indicated by the simple linear regression. The principal component analysis (PCA), with 80% of explanation, identified high values of SGR, density and Y for the 10:1 and high values of alkalinity, hardness, DT and NO2 for the 20:1. Thus, the use of effluent from Tilapia farming in a biofloc system with a C:N ratio of 10:1 provided better production results for D. magna, demonstrating that it is an option for the production of live feed for aquaculture.

O presente trabalho teve como objetivo produzir Daphnia magna em água residual do cultivo de Tilápia em sistema de bioflocos, avaliando relações carboidrato:nitrogênio. O experimento teve duração de 30 dias seguindo delineamento experimental inteiramente casualizado, sendo os tratamentos: C:N 10:1, C:N 15:1 e C:N 20:1, todos com oferta de Chlorella vulgaris na dieta. Foram analisadas as variáveis físico-químicas: temperatura, OD, pH, TAN, NO2, dureza e alcalinidade; e as variáveis de crescimento: Densidade média máxima (DMX), Dia de máxima densidade (DMD), Taxa de crescimento específico (TCE), Tempo de duplicação (TD) e Rendimento (R). As variáveis de qualidade de água mantiveram-se na faixa ideal para a espécie, apresentando diferenças significativas (p<0,05) entre os tratamentos para: pH, OD, dureza e alcalinidade. Com relação às variáveis de crescimento, foram observadas diferenças significativas (p<0,05), com maiores valores de DMX, R e TCE para o tratamento 10:1 (3.433 ± 267 ind L-1, 245 ± 19 ind L-1 dia-1 e 45,3 ± 0,6 % dia-1, respectivamente) e menor para o 20:1 (1.011 ± 283 ind L-1, 55 ± 15 ind L-1 dia-1 e 28,3 ± 1,6 % dia-1, respectivamente). O DMD ocorreu no 12º dia para o 10:1 e no 18° dia para os 15:1 e 20:1. As variáveis alcalinidade e dureza tiveram destaque sobre as variáveis de crescimento sendo também evidenciada na regressão linear simples. Já a análise de componentes principais (PCA), com 80% de explicação, identificou altos valores de TCE, densidade e R para o 10:1 e, elevados valores de alcalinidade, dureza, TD e NO2 para o 20:1. Assim, o uso de efluente proveniente do cultivo de Tilápia em sistema de bioflocos com relação C:N de 10:1 propiciou melhores resultados produtivos para a D. magnademonstrando ser uma opção para a produção de alimento vivo para a aquicultura.

Assuntos