Sanidade de peixes em sistema de recirculação de água

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Aquicultura, Florianópolis, 2019.Este estudo avaliou a sanidade de peixes em um sistema de recirculação de água (SRA) para aquicultura, dimensionado e estimado para uma biomassa de 670Kg, na densidade de 16gL-1 de peixes com produção diária de 1.608g de nitrogênio amoniacal total (NAT). Para confirmar se essa é a capacidade efetiva que o SRA suporta sem trazer prejuízos aos peixes, foi realizado teste de desempenho do SRA, estocando durante 54 dias tilápias, Oreochromis niloticus, e piavas, Leporinus obtusidens, na biomassa inicial de 175kg de peixes na densidade de 4,9gL-1 de peixes. Durante todo período, os parâmetros físico-químicos da água foram monitorados: oxigênio dissolvido 5,53±0,24mg L-1; temperatura 27,99±0,19°C; pH 7,48±0,21; alcalinidade 33,35±2,45mg CaCO3 L-1; dureza 36,85±2,57mg CaCO3 L-1; salinidade 0,37±0,07mg L-1; condutividade elétrica 732,57; 52,87µ.S cm-1; nitrogênio amoniacal total 0,274±0,007mg L-1, nitrito 0,026±0,025mg L-1 e nitrato 35,82±9,06mg L-1 todos os parâmetros se mantiveram na faixa adequada para o cultivo dos peixes. O desempenho zootécnico dos peixes também foi monitorado, demonstrando a influência direta e satisfatória do SRA nos peixes, atingindo a biomassa final de 329 Kg de peixes e densidade de 9,1 g de peixes L-1. Análises hematológicas e parasitológicas foram realizadas dos peixes no final dos 54 dias de estocagem e comparados com os valores do início do experimento. Com as respostas hematológicas foi possível evidenciar a existência de um agente estressor, ocorrendo aumento significativo (pAbstract: This study evaluated the health of fish in an aquaculture water recirculation system (SRA), estimated and estimated for a 670Kg biomass, at 16gL-1 density of fish with daily production of 1,608g of total ammonia nitrogen (NAT). . To confirm if this is the effective capacity that SARS supports without causing damage to fish, SARS performance testing was performed, stocking for 54 days tilapia, Oreochromis niloticus, and piavas, Leporinus obtusidens, in the initial biomass of 175kg of fish in density. 4.9gL-1 of fish. Throughout the period, the physicochemical parameters of the water were monitored: dissolved oxygen 5.53 ± 0.24mg L-1; temperature 27.99 ± 0.19 ° C; pH 7.48 ± 0.21; alkalinity 33.35 ± 2.45mg CaCO3 L-1; hardness 36.85 ± 2.57mg CaCO3 L-1; salinity 0.37 ± 0.07mg L-1; electrical conductivity 732.57; 52.87µS cm -1; total ammonia nitrogen 0.274 ± 0.007mg L-1, nitrite 0.026 ± 0.025mg L-1 and nitrate 35.82 ± 9.06mg L-1 all parameters were in the proper range for fish cultivation. The zootechnical performance of the fish was also monitored, demonstrating the direct and satisfactory influence of SARS on fish, reaching the final biomass of 329 kg of fish and density of 9.1 g of fish L-1. Hematological and parasitological analyzes were performed on the fish at the end of 54 days of storage and compared with the values at the beginning of the experiment. With the hematological responses it was possible to evidence the existence of a stressor agent, occurring significant increase (p <0.05) of neutrophils (12.15 ± 6.66 to 21.43 ± 11.68%) and significant decrease (p < Erythrocyte values (1.81 ± 0.64 to 2.13 ± 0.54 106µL-1) and lymphocytes (22.4 ± 8.66 to 13.67 ± 8.38%) between beginning and end of the experiment. Parasitological analysis showed a significant increase (p <0.05) in the number of parasitized fish (25% to 63%) and abundance (3.55 ± 6.44 to 9.37 ± 9.99) after 54 days

Recirculating aquaculture systems affects hematological parameters and increases ectoparasite susceptibility in Nile tilapia Oreochromis niloticus

We herein evaluated the hematology and parasitology of Nile tilapia previously raised in an earthen pond and transferred to a recirculating aquaculture system (RAS) to verify any possible influence of RAS on such health parameters. For this, 780 tilapias with an initial average weight and length of 91.05 ± 27.08 g and 17.45 ± 1.91 cm, respectively, were distributed in three tanks (2.0 m3) attached to the RAS, where they remained for 54 d. Throughout the period, water quality parameters remained within the range suitable for the cultivation of the species. Tilapia growth performance was satisfactory in the RAS, reaching a final biomass of close to 300 kg and survival of 98%. Hematological and parasitological analyses at the end of 54 d showed possible stress in RAS, with a significant increase in neutrophils from 12.15 ± 6.66 (earthen pond) to 21.43 ± 11.68% (RAS) and erythrocytes from 1.81 ± 0.24 (earthen pond) to 2.13 ± 0.14 (RAS), and a significant decrease in lymphocytes from 22.4 ± 2.66 (earthen pond) to 13.67 ± 3.38 (RAS). Furthermore, parasitological analysis showed a significant increase in the number of parasitized fish (25% to 63%) and abundance (3.55 ± 6.44 to 9.37 ± 9.99) after 54 d. It was concluded that tilapia cultivation in RAS can cause hematological changes and increase parasitism