Biochemical effects of encapsulated radiovaccine via alginate nanoparticles as useful strategy for booster in immunized rainbow trout against Ichthyophytirius multifiliis

Background: The Ichthyophthirius multifiliis is one of the most important protozoan pathogens of farmed and wild fish populations. The vaccination against I. multifiliis can be considered as an alternative to chemical treatments. There are three routes of vaccination; the injection, immersion and oral administration. Oral immunization would be a good candidate since handling fish is not required, it is a not stressful method and it needs less time and labor. In this study a nanoparticle system for protection of radiovaccine and efficient oral vaccine delivery to the intestinal tract against I. multifiliis was tested in rainbow trout.Materials, Methods & Results: Fifty rainbow trout (40 - 50 g) were infected with I. multifiliis via live trophont, trophont were collected with 200-mesh sieve. After collection, dose of gamma ray (170 Gray) was used for irradiation of parasite. Commercial Ergosan was suspended in sterile 0.15 M (pH 7.2) and sonicated. Remaining powder was irradiated by gamma irradiator. The alginate nanoparticle encapsulated radiovaccine was achieved by the addition of PBS (1 mL) to the alginate nanaoparticle solution (4 mL) plus radiovaccine (37˚C, pH 7.5). Fish were distributed equally into 5 groups (60 fish/aquarium). In this study, elevated levels of WBC was found in fish immunized with non-capsulated and encapsulated radiovaccine at 20 days after challenge (P < 0.05). No significant differences in haematocrit and RBC were found among all of groups (P < 0.05). Also, plasma total protein level was found to decrease in vaccinated fish with non-capsulated radiovaccine at 7 and 20 days after challenge. Significant decrease in glucose level was shown in immunized rainbow trout with encapsulated radiovaccine (P < 0.05). A significant increase in plasma glucose level was shown in rainbow trout challenged with live trophonts at 7 days after challenge (P < 0.05).[...](AU)

Biochemical effects of encapsulated radiovaccine via alginate nanoparticles as useful strategy for booster in immunized rainbow trout against Ichthyophytirius multifiliis

Background: The Ichthyophthirius multifiliis is one of the most important protozoan pathogens of farmed and wild fish populations. The vaccination against I. multifiliis can be considered as an alternative to chemical treatments. There are three routes of vaccination; the injection, immersion and oral administration. Oral immunization would be a good candidate since handling fish is not required, it is a not stressful method and it needs less time and labor. In this study a nanoparticle system for protection of radiovaccine and efficient oral vaccine delivery to the intestinal tract against I. multifiliis was tested in rainbow trout.Materials, Methods & Results: Fifty rainbow trout (40 - 50 g) were infected with I. multifiliis via live trophont, trophont were collected with 200-mesh sieve. After collection, dose of gamma ray (170 Gray) was used for irradiation of parasite. Commercial Ergosan was suspended in sterile 0.15 M (pH 7.2) and sonicated. Remaining powder was irradiated by gamma irradiator. The alginate nanoparticle encapsulated radiovaccine was achieved by the addition of PBS (1 mL) to the alginate nanaoparticle solution (4 mL) plus radiovaccine (37˚C, pH 7.5). Fish were distributed equally into 5 groups (60 fish/aquarium). In this study, elevated levels of WBC was found in fish immunized with non-capsulated and encapsulated radiovaccine at 20 days after challenge (P < 0.05). No significant differences in haematocrit and RBC were found among all of groups (P < 0.05). Also, plasma total protein level was found to decrease in vaccinated fish with non-capsulated radiovaccine at 7 and 20 days after challenge. Significant decrease in glucose level was shown in immunized rainbow trout with encapsulated radiovaccine (P < 0.05). A significant increase in plasma glucose level was shown in rainbow trout challenged with live trophonts at 7 days after challenge (P < 0.05).[...]

Hematologia de tilápia-do-nilo alimentada com suplemento à base de algas frente a desafios de estresse agudo e crônico / Hematology of Nile tilapia fed supplementation with algae challenged by acute and chronic stress

Avaliou-se o efeito da suplementação com produto à base de algas, ergosan, em dietas para tilápias Oreochromis niloticus, submetidas ao desafio de estresse agudo e crônico sobre as características hematológicas. O ensaio foi realizado com tilápias jovens (15g) em caixas de 500L de capacidade de estocagem, em sistema com recirculação da água, com fluxo constante, na densidade de 35 peixes por caixa. Os peixes foram alimentados com as dietas-teste durante 10 dias e, ao final deste período, voltaram a receber dieta isenta de ergosan, quando foram submetidos aos desafios de estresses agudo e crônico. Utilizou-se o delineamento inteiramente ao acaso (DIC), em esquema fatorial 4x2, sendo testados: quatro porcentagens do suplemento 0; 0,25; 0,5 e 1 por cento de ergosan na ração em dois tipos de estresse, agudo e crônico. Os resultados permitem concluir que os estímulos de estresse aplicados foram capazes de provocar alterações fisiológicas nos peixes, incluindo redução no número de eritrócitos, eritroblastos e leucócitos e aumento do volume corpuscular médio dos eritrócitos. A administração oral de 1 por cento de suplemento durante 10 dias para juvenis de tilápia-do-nilo, em condição de estresse agudo, induz o incremento de 69 por cento no número de trombócitos circulantes.(AU)

The aim of this trial was to evaluate hematological parameters of tilapia Oreochromis niloticus fed diet supplemented with ergosan, an algae product, in a chronic and acute stress challenge. The experiment was carried out with juvenile tilapias Oreochromis niloticus (15g), in 500 L-tanks linked at a water recirculation system, with constant water flow and controlled temperature, stoking 35 fish/tank. Fish were fed test-diets during 10 days and, at the end of this period, received a diet without supplementation, when they were submitted to chronic and acute stress challenge. Fish were distributed in a completely randomized design, in a factorial scheme 4x2: four supplement levels (0; 0.25; 0.5 and 1 percent supplement in the diet) with two stresses (chronic and acute). Results showed the stress stimulus applied were able to induce physiologic changes on fish, including reduction of erythrocytes, erythroblasts and leucocytes number and increasing medium corpuscular volume. Oral administration of 1 percent supplement during 10 days for Nile tilapia juveniles under acute stress induces a higher thrombocyte number (69 percent) in the blood.(AU)

The effect of alginate incorporated in the ration on performance and handling of juvenile Nile tilapia / O efeito de alginatos incorporados `a ração sobre o desempenho produtivo e manejo de juvenis de tilápia do Nilo

The alginic acid is extracted from seaweed and when used in fish ration may induce immunomodulatory and immunostimulants responses. This study aimed to evaluate the effect of alginic acid incorporated in the ration on performance and handling of juvenile Nile tilapia, Oreochromis niloticus. The first phase of the experiment occurred in two excavated ponds earth. 57,000 juveniles were used for Nile tilapia, local strains with the average weight of 14 grams. The juvenile Nile tilapia received the experimental diet treated with ergosan at a dose of 1% of the diet. The survival rate of fish and feed conversion in the experimental Nile tilapia was higher than the control Nile tilapia. In the second stage 54,126 juveniles with average weight 40.63 grams, were used. These fish were transferred to 16 fish cages. There were no significant differences in mortality rate between treatments. The highest mortality occurred between the third and seventh days after the handling. The data confirm that the transfer of juvenile Nile tilapia in the ponds to fish cages is a strong stressor.

Os ácidos algínicos são extraídos de algas marinhas e quando utilizados na dieta dos peixes podem induzir respostas imunomoduladoras e imunoestimulantes. Este trabalho teve o objetivo de avaliar o efeito dos alginatos incorporado na ração sobre o desempenho produtivo e manejo de juvenis de tilápia do Nilo, Oreochromis niloticus. A primeira fase do experimento ocorreu em dois viveiros escavados de terra. Foram utilizados 57.000 juvenis de tilápia do Nilo, variedade local com peso médio de 14 gramas. Os Juvenis do viveiro experimental receberam ração tratada com ergosan na dose de 1% da dieta. A taxa de sobrevivência dos peixes e a conversão alimentar dos peixes alojados no viveiro experimental foi superior ao daqueles alojados no viveiro controle. Na segunda fase foram utilizados 54.126 juvenis de 40,63 gramas. Estes peixes foram transferidos para 16 tanques-rede. Não houve diferenças significativas de taxa de mortalidade dos peixes entre os tratamentos. A maior mortalidade ocorreu entre o terceiro e sétimo dias após o manejo. Os dados confirmam que a transferência de juvenis de tilápia do Nilo de viveiros de terra para tanques-rede é um agente estressor.

The effect of alginate incorporated in the ration on performance and handling of juvenile Nile tilapia / O efeito de alginatos incorporados `a ração sobre o desempenho produtivo e manejo de juvenis de tilápia do Nilo

The alginic acid is extracted from seaweed and when used in fish ration may induce immunomodulatory and immunostimulants responses. This study aimed to evaluate the effect of alginic acid incorporated in the ration on performance and handling of juvenile Nile tilapia, Oreochromis niloticus. The first phase of the experiment occurred in two excavated ponds earth. 57,000 juveniles were used for Nile tilapia, local strains with the average weight of 14 grams. The juvenile Nile tilapia received the experimental diet treated with ergosan at a dose of 1% of the diet. The survival rate of fish and feed conversion in the experimental Nile tilapia was higher than the control Nile tilapia. In the second stage 54,126 juveniles with average weight 40.63 grams, were used. These fish were transferred to 16 fish cages. There were no significant differences in mortality rate between treatments. The highest mortality occurred between the third and seventh days after the handling. The data confirm that the transfer of juvenile Nile tilapia in the ponds to fish cages is a strong stressor.

Os ácidos algínicos são extraídos de algas marinhas e quando utilizados na dieta dos peixes podem induzir respostas imunomoduladoras e imunoestimulantes. Este trabalho teve o objetivo de avaliar o efeito dos alginatos incorporado na ração sobre o desempenho produtivo e manejo de juvenis de tilápia do Nilo, Oreochromis niloticus. A primeira fase do experimento ocorreu em dois viveiros escavados de terra. Foram utilizados 57.000 juvenis de tilápia do Nilo, variedade local com peso médio de 14 gramas. Os Juvenis do viveiro experimental receberam ração tratada com ergosan na dose de 1% da dieta. A taxa de sobrevivência dos peixes e a conversão alimentar dos peixes alojados no viveiro experimental foi superior ao daqueles alojados no viveiro controle. Na segunda fase foram utilizados 54.126 juvenis de 40,63 gramas. Estes peixes foram transferidos para 16 tanques-rede. Não houve diferenças significativas de taxa de mortalidade dos peixes entre os tratamentos. A maior mortalidade ocorreu entre o terceiro e sétimo dias após o manejo. Os dados confirmam que a transferência de juvenis de tilápia do Nilo de viveiros de terra para tanques-rede é um agente estressor.