RESUMO A fase de berçário no cultivo da tilápia utilizando a tecnologia de bioflocos é importante, pois aumenta a previsibilidade da produção. No entanto, nenhum estudo avaliando as densidades de estocagem de tilápias focou no uso apenas de uma fonte de carbono inorgânico para promover o processo de nitrificação como principal forma de controle de nitrogênio no sistema. Este estudo teve como objetivo avaliar o efeito de densidades de estocagem no berçário, em sistema de bioflocos quimioautotróficos, na qualidade da água, parâmetros zootécnicos e sanidade da tilápia-do-nilo (Oreochromis niloticus). Quinze tanques (capacidade de 100 L) contendo aquecedores (28 ±1°C) e inoculados com bioflocos maduros foram utilizados. Setecentos e cinquenta alevinos de tilápia (pesando 0,66 ±0,17 g) foram distribuídos nos tanques, em triplicata, de forma que as densidades nos tanques atingissem 200, 350, 500, 650 e 800 peixes m-3. O oxigênio dissolvido e o crescimento da tilápia mostraram uma relação linear negativa com a densidade de peixes. Uma relação linear positiva com a densidade foi observada para os compostos nitrogenados, alcalinidade, sólidos suspensos, produtividade e conversão alimentar. No entanto, os parâmetros de qualidade da água foram adequados para a tilápia e permitiram um bom desempenho zootécnico independente da densidade de estocagem. Parâmetros hematológicos, sobrevivência dos peixes e uniformidade no crescimento não se alteraram com as densidades. Os sólidos totais em suspensão produzidos pela biomassa de peixes apresentaram relação quadrática com a densidade, com maior eficiência dos tanques estocados com 406 peixes m-3. É possível produzir no berçário de tilápias utilizando sistemas de bioflocos quimioautotróficos com densidades de até 800 peixes m-3 e produtividade superior a 12 kg m-3. Mas a densidade de 406 peixes m-3 apresentou melhor eficiência na produção de sólidos por biomassa.

ABSTRACT The nursery phase in tilapia using biofloc technology is important as it increases the predictability of production. However, none studies evaluating the stocking densities of tilapia focused only on the use of an inorganic carbon source to promote the nitrification process as the main way to control nitrogen in the system. This study aimed to evaluate the effect of varied nursery stocking densities, in a chemoautotrophic biofloc system, on water quality, zootechnical parameters, and health of Nile tilapia (Oreochromis niloticus). Fifteen tanks (100 L capacity) containing heaters (28 ±1°C) inoculated with mature bioflocs were used. Seven hundred and fifty tilapia fingerlings (weighing 0.66 ±0.17 g) were distributed in the tanks, in triplicate, so that the densities in the tanks reached 200, 350, 500, 650, and 800 fish m-3. Dissolved oxygen and tilapia growth showed a negative linear relationship with fish density. A positive linear relationship with density was observed for nitrogen compounds, alkalinity, suspended solids, yield, and feed conversion. However, the water quality parameters were appropriate for tilapia and allowed good zootechnical performance irrespective of the fish density. Hematological parameters, fish survival, and uniformity in growth did not alter with densities. Total suspended solids produced by fish biomass showed a quadratic relationship with density, with the highest efficiency of the tanks stocked with 406 fish m-3. It is possible to construct a tilapia nursery in chemoautotrophic biofloc systems with densities reaching up to 800 fish m-3 and yield exceeding 12 kg m-3. But the density of 406 fish m-3 had a better efficiency in solid production by biomass.

Resumo O objetivo deste estudo foi avaliar o desempenho de crescimento e saúde em juvenis de tilápia-do-nilo (Oreochromis niloticus) alimentados com dieta prática com substituição total da farinha de peixe (FP) por farelo de soja (FS), bem como o efeito na sobrevivência, após desafio patogênico com Aeromonas hydrophila. Duzentos juvenis de tilápia-do-nilo foram alojados em 8 tanques (800 L). O experimento consistiu de dois tratamentos: dieta comercial formulada com FP (controle) e dieta prática com substituição total do FP pelo FS. Foram mensuradas as variáveis de qualidade da água, parâmetros zootécnicos e hematológicos. Além disso, ao final do experimento, os peixes foram submetidos a um desafio com A. hydrophila. Maior custo por kg de peixe foi obtido no tratamento controle (com FP). A retenção de N foi maior nos peixes alimentados com dieta sem FP, enquanto os parâmetros hematológicos, imunológicos e a sobrevivência após o desafio experimental não diferiram entre os tratamentos. É possível reduzir os custos dietéticos substituindo a FP pelo FS sem afetar o desempenho do crescimento e a saúde do animal, além de beneficiar o meio ambiente ao reduzir a excreção de N na água.

Abstract This study aimed to evaluate the growth performance and animal health in juveniles of Nile tilapia (Oreochromis niloticus) fed a practical diet with total replacement of fishmeal (FM) by soybean meal, as well the effect on survival, following pathogenic challenge with Aeromonas hydrophila. Two hundred juveniles of Nile tilapia were stored in 8 tanks (800 L). The experiment consisted of two treatments: a commercial diet formulated with FM (control) and a practical diet with total replacement of FM by soybean meal (SM). The variables of water quality, zootechnical and hematological parameters were measured. In addition, at the end of the experiment, the fish were submitted to a challenge with A. hydrophila. Higher cost per kg of fish was obtained in the control treatment (with FM). N retention was higher in fish fed a diet without FM, while hematological, immunological parameters and survival after the experimental challenge did not differ between treatments. It is possible to reduce dietary costs by replacing FM with SM without affecting growth performance or animal health, in addition to benefiting the environment by reducing the excretion of N in water.

Abstract The objective of this work was to evaluate the effect of autochthonous and allochthonous lactic acid bacteria (LAB) in two species of lambaris (Astyanax bimaculatus and Astyanax fasciatus), and to investigate the effects on intestinal microbiota and hematological changes. Two experiments were carried out, one for each lambari species, both assays were divided into three treatments: autochthonous LAB, allochthonous LAB and control. The 10% inoculum was included on diet in the LAB treatments and sterile medium for control. After 30 days for A. bimaculatus LAB indigenous changes all bacteria groups analyzed, while allochthonous LAB just decrease Staphylococcus spp. count. Though for A. fasciatus his autochthone LAB reduced the staphylococcal count. In hematology, for A. bimaculatus autochthonous LAB showed a higher number of thrombocytes, lymphocytes, monocytes and total leukocytes in the circulatory system than the control. Though for A. fasciatus his autochthone LAB showed a higher number of total lymphocytes and leukocytes than the control, while Lactobacillus sp. acting as an allochthone, it did not differ among treatments. In conclusion, both LAB (Lactobacillus sp. and L. lactis) promoted more beneficial changes in the microbiota and hematological profile when they act as an autochthone probiotic, demonstrating a probiotic-associated host.

Abstract This study aimed to evaluate the effects of the dietary supplementation Curcuma longa hydrolate on Nile tilapia (Oreochromis niloticus) reared in a recirculation system. Hemato-immunological parameters, growth performance, nitrogen and phosphorus retention, as well as body composition and its interaction with the intestinal microbiota, were studied. Nile tilapia fingerlings (120) were distributed randomly in 8 polyethylene tanks (40 L). The experimental units were divided into two treatments, in quadruplicate: commercial diet supplemented with 2.5% of C. longa hydrolate and commercial diet without supplementation (control). After 45 days, the treatment supplemented hydrolate showed higher survival than the control group, 95.25% and 82.22%, receptively. In the blood profile, fish supplemented with hydrolate had a higher count of total leukocytes and neutrophils, as well as mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration, than control group. The hydrolate group showed a substantial increase in the relative abundance of Cetobacterium and Romboutsia, as well as lower diversity in gut microbiota. The dietary addition of C. longa hydrolate for Nile tilapia seems to have a beneficial effect on gut microbiota, in addition to a likely positive effect on the physiological performance of Nile tilapia by maintaining intestinal homeostasis and promoting survival in reared conditions.

RESUMO: Este trabalho teve como objetivo avaliar diferentes concentrações e tempos de exposição do hidrolato de Mentha × villosa para o controle de monogenéticos em Tilápia-do-nilo (Oreochromis niloticus). Folhas de Mentha × villosa (150 g) foram homogeneizadas e o hidrolato foi obtido por hidrodestilação por 4 h em aparelho de Clevenger. Em seguida, 50 tilápias foram divididas em dez grupos (cinco peixes cada) e submetidas a banhos terapêuticos por 15 minutos em cinco diferentes concentrações de hidrolato (0, 10, 20, 40 e 80 ml.L-1; × 2 repetições). Após a identificação de uma concentração de hidrolato adequada, outras 50 tilápias foram divididas em dez grupos (cinco peixes cada) e submetidas a banhos terapêuticos na concentração de hidrolato identificada por cinco durações diferentes (0, 15, 30, 45 e 60 minutos; × 2 repetições). Em ambas as etapas, o muco e as guelras foram analisados para determinar os índices parasitológicos. A concentração de hidrolato de 20 ml.L-1 apresentou eficácia de 59,9% e a maior redução na prevalência do patógeno, abundância média e infecção média em relação ao controle e a menor concentração (10 ml.L-1). Para a duração, os melhores efeitos antiparasitários foram alcançados com o banho terapêutico de 60 minutos, uma vez que resultou em 89,28% de eficácia antiparasitária. Portanto, concluiu-se que banhos terapêuticos de hidrolato de M. × villosa na concentração de 20 ml.L-1 por 60 minutos têm efeitos antiparasitários satisfatórios e podem ser usados para controlar infestações monogenéticas nas brânquias e muco da Tilápia-do-nilo (O. niloticus).

ABSTRACT: This paper o evaluated different concentrations and exposure times of Mentha × villosa hydrolate for the control of monogeneans in Nile tilapia (Oreochromis niloticus). Mentha × villosa leaves (150 g) were homogenized and the hydrolate was obtained by hydrodistillation for 4 h in a Clevenger apparatus. Fifty tilapia were then divided into ten groups (five fish each) and subjected to therapeutic baths for 15 minutes in five different hydrolate concentrations (0, 10, 20, 40, and 80 ml.L-1;× 2 replicates). After a suitable hydrolate concentration was identified, another 50 tilapia were divided into ten groups (five fish each) and subjected to therapeutic baths at the identified hydrolate concentration for five different durations (0, 15, 30, 45, and 60 minutes;× 2 replicates). In both steps, the mucus and gills were analyzed to determine parasitological indices. The hydrolate concentration of 20 ml.L-1 showed an efficacy of 59.9% and the biggest decrease in pathogen prevalence, average abundance, and average infection compared to the control and the lowest concentration (10 ml.L-1). For duration, the best antiparasitic effects were achieved with the 60-minute therapeutic bath, as it resulted in 89.28% antiparasitic efficacy. Therefore, it was concluded that therapeutic baths of M. × villosa hydrolate at a concentration of 20 ml.L-1 for 60 minutes have satisfactory antiparasitic effects and could be used to control monogenetic infestations in the gills and mucus of Nile tilapia (O. niloticus).

RESUMO: O objetivo deste trabalho foi avaliar as alterações na microbiota do trato intestinal, parâmetros hematológicos e índices zootécnicos de lambaris-do-rabo-amarelo (Astyanax bimaculatus) alimentados com diferentes frequências de oferta do probiótico (Lactobacillus spp.). Os lambaris (1.200) foram distribuídos em doze caixas, divididos em três tratamentos, oferta de 100%, 25% e 0% (controle) de alimentações suplementadas com probiótico. Após 87 dias, os peixes alimentados com dieta suplementada, independente da frequência (100% e 25%), apresentaram aumento na contagem total de bactérias ácido láticas 7,99±0,15log UFC mL-¹ e -7,04±1,29log UFC mL-¹, respectivamente, no trato intestinal e redução de Pseudomonas spp. tanto em 100% quanto em 25% (4,09 ± 0,84 log UFC mL-¹ e 4,00±1,12 log UFC mL-¹, respectivamente) em relação ao tratamento controle (6,74±1,04log UFC mL-¹). Os peixes alimentados com 100% das dietas suplementadas com probiótico apresentaram maior contagem de leucócitos (47,7±6,7x103µL-1), linfócitos (36,0±2,6x103µL-1), monócitos (12,0±4,2x103µL-1), assim como maior peso médio final (10,60±0,89g) e taxa de crescimento semanal (0,80±0,08g.semana-1) que os demais tratamentos (25% de oferta de probiótico e controle). O probiótico (Lactobacillus spp.) oferecido em 25% de alimentos (ou mais) altera a microbiota de lambari de rabo amarelo (A. bimaculatus), no entanto, deve ser oferecido em 100% de alimentos para melhorar o perfil hematologia e desempenho produtivo.

ABSTRACT: The aim of this research was to evaluate the changes in intestinal tract microbiota, hematological parameters and zootechnical indexes of yellowtail lambaris (Astyanax bimaculatus) fed with different probiotic supply frequencies (Lactobacillus spp.). Lambaris (1,200) were distributed in twelve boxes, divided in three treatments, 100% supply; 25% and 0% (control) of feeds supplemented with probiotic. After 87 days, fish fed with supplemented diet, regardless of frequency (100% and 25%), showed an increase in the total lactic acid bacteria count of 7.99±0.15 log CFU mL-1 and 7.04±1, 29 log UFC mL-¹ respectively, in the intestinal tract and decrease of Pseudomonas spp. in both 100% and 25% (4.09±0.84log UFC mL-1 and 4.00±1.12log UFC mL-1, respectively) in relation to the control treatment (6.74±1.04log UFC mL-1). Fish fed with 100% of diets supplemented with probiotics had a higher leukocyte count (47.7±6.7x103μL-1), lymphocytes (36.0±2.6x103μL1), monocytes (12.0±4.2x103μl-1), as well as higher mean final weight (10.60±0.89g) and weekly growth rate (0.80±0.08g.week-1) than the other treatments (25% of probiotic offered and control). Probiotic (Lactobacillus spp.) offered in 25% of feeds (or more) alters the yellowtail lambari microbiota (A. bimaculatus); however, must be offer in 100% of feeds to improve the hematology profile and productive performance.

RESUMO. O presente trabalho avaliou os parâmetros imunológicos e a resistência contra o Vibrio sp. (CPQBA 378-12 DRM01) de camarões marinhos Litopenaeus vannamei alimentados com diferentes níveis de concentrado proteico de soja em substituição à farinha de peixe e cultivados em sistema de bioflocos. Foram formuladas quatro dietas com 0, 33, 66 e 100 % de concentrado proteico de soja em substituição a farinha de peixe. Os camarões foram cultivados em 12 tanques de 800 L com 250 camarões m-3, sob temperatura e aeração constantes. Após 42 dias, 36 animais (14,21 ± 0,89 g) por tratamento foram desafiados com Vibrio sp. (1 x 105 UFC mL-1 - DL10). Antes e após o desafio foi coletada hemolinfa para avaliação dos parâmetros imunológicos (título aglutinante, concentração de proteína no soro e atividade da fenoloxidase). Não houve diferença na resistência ao desafio e nos parâmetros imunológicos entre os tratamentos. Portanto, o cultivo de L. vannamei em sistema de bioflocos utilizando dietas com substituição total ou parcial com concentrado proteico de soja não afeta sua imunocompetência e susceptibilidade a infecção bacteriana.

ABSTRACT. Litopenaeus vannamei shrimp were reared in a bioflocs system and fed different levels of soybean protein concentrate as a replacement for fishmeal, and both immunological parameters of this marine shrimp and its resistance to Vibrio sp. infection (CPQBA 378-12 DRM01) were evaluated. Four different diets were formulated with 0, 33, 66 and 100 % of soybean protein concentrate as a substitute for fishmeal. Shrimp were reared in a biofloc system in twelve 800 L tanks (250 shrimp m-3) maintained at constant aeration and temperature. After 42 days, 36 animals (14.21 ± 0.89 g) per treatment were challenged with Vibrio sp. (1 x 105 CFU mL-1 - LD10), and hemolymph was collected before and after challenge to perform immunological assays (agglutination titer, concentration of protein and phenoloxidase activity). Shrimp fed with the experimental diets showed no difference in their resistance to infection and haemato-immunological parameters. Thus, rearing L. vannamei in a biofloc system on diets containing either partial or total replacement of fishmeal for soybean protein concentrate did not affect either immunocompetence or susceptibility to infection.

ABSTRACT This study aimed to assess the final body weight, weekly weight gain, yield, apparent feed efficiency, protein efficiency ratio, and feed intake of the Pacific white shrimp (Litopenaeus vannamei) fed four diets containing different levels of soy protein concentrate (SPC) as a replacement for fishmeal, reared in a super-intensive biofloc system. Diets consisted of replacing 209 g kg-1 fishmeal at 0, 33, 66, and 100% SPC. Shrimp were raised in a biofloc system using twelve experimental units stocked with 250 shrimp m-3 under constant aeration (O2>5mg L-1) and temperature (29±0.5 °C). No significant differences among treatments were observed based on water quality parameters. Shrimp fed diets with 0 and 33% substitution exhibited the highest weekly growth (1.88 and 1.79 g per week) and final weights (15.2 and 14.7 g) compared with shrimp fed the 66 and 100% replacement. A lower feed intake was observed for shrimp fed the 33% SPC diet (3.18 kg per experimental unit) compared with 0% replacement (3.62 kg). Shrimp fed the 33% replacement achieved a similar performance and lower feed intake than animals fed diet without replacement.

ABSTRACT The objective of this study was to evaluate the use of a diet supplemented with Lactobacillus plantarum on performance, immunological parameters, and bacterial microbiota of the digestive tract of white leg shrimp (Litopenaeus vannamei). We used six earthen ponds (1.2 ha) stocked with 14 shrimp m−2 (3 g mean weight). Three ponds received a diet supplemented with L. plantarum and three were maintained as control. The survival and feed efficiency of shrimp fed the supplemented diet were greater than that observed in shrimp fed the control diet, with survival values of 83.02±6.12% and 74.65±9.07% and feed efficiencies of 117.97±4.45% and 104.46±7.30%, respectively. However, we observed no differences in weight gain. The intestines of shrimp fed probiotics had lower counts of Vibrio spp. and higher counts of lactic acid bacteria, compared with those of control shrimp. Diets supplemented with L. plantarum alter the intestinal bacterial microbiota of shrimp, resulting in increased survival and feed efficiency.

O objetivo deste trabalho foi avaliar as alterações na microbiota do trato intestinal e desempenho zootécnico de alevinos de tilápia do Nilo (Oreochromis niloticus) alimentados com dietas suplementadas com Lactobacillus plantarum. Cento e vinte alevinos revertidos sexualmente foram distribuídos em seis caixas, divididos em dois tratamentos, em triplicata: alevinos alimentados com dieta suplementa com L. plantarum e alevinos alimentados com dieta controle. Após 42 dias, as tilápias alimentadas com a dieta suplementada com L. plantarum apresentaram maior número de bactérias ácido-lácticas, 3,5x104 UFC e 1,1x102 UFC por g de trato, e menor de bactérias totais, 5,8x106 UFC e 5,2x107 UFC por g de trato intestinal, em relação aos alimentados com dieta controle, além de incrementar em 3,9% o ganho em peso semanal, 15,6% a biomassa final e 15,5% eficiência alimentar. O uso de probiótico na alevinagem de tilápia eleva a produtividade.

The objective of this study was to evaluate alterations in the intestinal tract microbiota and growth performance of Nile tilapia (Orechromis niloticus) fed diets supplemented with Lactobacillus plantarum. One hundred and twenty sexually reversed fingerlings were stocked in six aquaria and divided into two treatments, in triplicate: fingerlings fed diet supplement with L. plantarum and fingerlings fed control diet. After 42 days, tilapia fed the diet supplemented with L. plantarum had higher amount of lactic acid bacteria, 3,5x104 CFU and 1,1x102 CFU per g tract, and lower total bacteria, 5,8x106 CFU and 5,2x107 CFU per g tract, than the fish fed the control diet. Furthermore, probiotics increased 3,9% the weekly weight gain, 15,6% final biomass and 15,5% feed efficiency. The use of probiotics in tilapia hatcheries boosts productivity.

O objetivo deste trabalho foi isolar cepas de bactérias ácido-lácticas, com potencial probiótico do trato digestório de camarões marinhos e realizar seleção in vitro baseada em múltiplos caracteres. O ideótipo (cepa ideal proposta) foi definido por meio das maiores médias para os caracteres velocidade máxima de crescimento, contagem final de células viáveis e halo de inibição contra nove patógenos de origem continental e marinha, e pelas menores médias para os caracteres tempo de duplicação e tolerância das cepas a NaCl (1,5 e 3%), pH (6, 8 e 9) e sais biliares (5%). Foram estimadas as distâncias de Mahalanobis (D²) entre as cepas avaliadas, e as melhores foram aquelas que apresentaram menor distância do ideótipo. Foram isoladas dez cepas de bactérias identificadas bioquimicamente como Lactobacillus plantarum (3), L. brevis (3), Weissella confusa (2), Lactococcus lactis (1) e L. delbrueckii (1). As cepas de L. plantarum apresentaram amplo espectro de ação e os maiores halos de inibição, tanto para patógenos Gram-positivos quanto negativos, alta taxa de crescimento e tolerância a todos os parâmetros avaliados. Em relação ao ideótipo, L. plantarum apresentou a menor distância de Mahalanobis (D²), seguida pelas cepas de W. confusa, L. brevis, L. lactis e L. delbrueckii. Entre as cepas bacterianas avaliadas, as de L. plantarum apresentam o maior potencial para uso como probiótico para camarões marinhos.

The objective of this work was to isolate strains of lactic acid bacteria with probiotic potential from the digestive tract of marine shrimp (Litopenaeus vannamei), and to carry out in vitro selection based on multiple characters. The ideotype (ideal proposed strain) was defined by the highest averages for the traits maximum growth velocity, final count of viable cells, and inhibition halo against nine freshwater and marine pathogens, and by the lowest averages for the traits duplication time and resistance of strains to NaCl (1.5 and 3%), pH (6, 8, and 9), and biliary salts (5%). Mahalanobis distance (D²) was estimated among the evaluated strains, and the best ones were those with the shortest distances to the ideotype. Ten bacterial strains were isolated and biochemically identified as Lactobacillus plantarum (3), L. brevis (3), Weissella confusa (2), Lactococcus lactis (1), and L. delbrueckii (1). Lactobacillus plantarum strains showed a wide spectrum of action and the largest inhibition halos against pathogens, both Gram-positive and negative, high growth rate, and tolerance to all evaluated parameters. In relation to ideotype, L. plantarum showed the lowest Mahalanobis (D²) distance, followed by the strains of W. confusa, L. brevis, L. lactis, and L. delbrueckii. Among the analyzed bacterial strains, those of Lactobacillus plantarum have the greatest potential for use as a probiotic for marine shrimp.

O objetivo deste trabalho foi determinar o método de coleta de fezes mais adequado para camarões marinhos (Litopenaeus vannamei) na determinação do coeficiente de digestibilidade aparente da proteína bruta e da matéria seca de dietas comerciais, e avaliar o efeito da suplementação de Lactobacillus plantarum na dieta sobre o coeficiente de digestibilidade aparente da proteína, da energia e da matéria seca. Foram testados três sistemas de coletas de fezes: decantação, sifonamento e dissecação dos animais. A coleta por decantação foi o sistema mais adequado para a determinação in vivo dos coeficientes de digestibilidade aparente da proteína bruta e da matéria seca das dietas, por apresentar baixo grau de lixiviação das fezes e por ser de fácil execução. Nos camarões alimentados com a dieta suplementada com L. plantarum, foi observado maior coeficiente de digestibilidade aparente da proteína (84,18±0,35%) e da energia (81,28±0,16%), quando comparado ao grupo controle (82,73±1,01 e 78,63±0,93%, respectivamente). O uso de L. plantarum como aditivo probiótico na ração pode trazer benefícios nutricionais a L. vannamei, com melhor aproveitamento dos nutrientes.

The objective of this work was to determine the most adequate feces collection method for sea shrimp (Litopenaeus vannamei) in the determination of the apparent digestibility coefficients of crude protein and dry matter of commercial diets, and to evaluate the effect of supplementation of Lactobacillus plantarum to the diet on the apparent digestibility coefficient of protein, energy, and dry matter. Three feces collection methods were tested: decanting, siphoning, and animal dissection. Decanting was the method best suited for the in vivo determination of the apparent digestibility coeffcients of crude protein and dry matter of commercial diets, since it promoted lower nutrient leaching from feces and was easy to perform. Shrimp fed the diet supplemented with probiotic showed higher apparent digestibility of crude protein (84.18±0.35%) and energy (81.28±0.16%) when compared to the control group (82.73±1.01 and 78.63±0.93%, respectively). The use of L. plantarum as a probiotic additive in shrimp diets can provide nutritional benefits to L. vannamei, with better nutrient utilization.

The aim of this study was to evaluate the immune response of hybrid surubim vaccinated by intraperitoneal injection and by immersion against Aeromonas hydrophila. Vaccine was prepared with formalin-inactivated A. hydrophila. Forty eight fishes (47±9g) were distributed in 12 tanks (4 fish / tank) in the following treatments (4 tanks / treatment): unvaccinated fish, vaccinated intraperitoneally and vaccinated by immersion. After 21 days, intraperitoneally vaccinated fishes showed the highest values of total protein and immunoglobulins, agglutination titer and serum antimicrobial activity. Lysozyme concentration in the serum was higher in the fishes vaccinated by immersion than unvaccinated fishes. Intraperitoneal vaccination induced the highest immune response and could be used to improve the fish resistance against motile Aeromonas.

The objective of this study was to investigate the growth of juvenile fat snook (Centropomus parallelus) in laboratory conditions when fed a diet supplemented with the probiotic Lactobacillus plantarum. Changes in the intestinal flora, haematological parameters and growth performance were assessed using 180 fishes (54.2 ± 13.4 g each). The fishes were subjected to two treatments divided into six cages: 1) feed supplemented with probiotic, and 2) feed without probiotic (control). The temperature, dissolved oxygen and salinity were maintained at 25 ± 1 ° C, 4.0 mg.L-1 and 33 ‰, respectively. After 10 weeks of culture, the fishes fed probiotic had reduced viable culturable heterotrophic bacteria and Vibrio spp. and increased lactic acid bacteria in the intestinal tract, as well as a higher number of thrombocytes, leukocytes and lymphocytes in the blood. No significant difference was observed in the growth, survival or body composition, but the hepatosomatic index was significantly higher in the fishes fed with probiotic and control.

Este estudo avaliou a eficácia da administração de vacina polivalente (bacterina), contra Aeromonas hydrophila, Pseudomonas aeroginosa e Enterococcus durans, por diferentes vias de aplicação em tilápia do Nilo, analisando parâmetros hematológicos e imunológicos no 7º e 21º dia após vacinação. Os tratamentos consistiram de: tilápias não vacinadas; tilápias vacinadas via injeção intraperitoneal (i.p.) contendo 2x10(8) bactérias inativadas·mL-1; tilápias alimentadas com ração contendo vacina na proporção de 2x10(7) bactérias inativadas·g-1, durante 5 dias; tilápias vacinadas por banho de imersão em 2x10(7) bactérias inativadas·mL-1, durante 20 minutos. Os peixes vacinados apresentaram maior porcentagem de hematócrito, número de eritrócitos e leucócitos durante o período do experimento, em relação aos não vacinados. O título de aglutinação do soro dos peixes vacinados intraperitonealmente foi superior nos dois períodos de avaliação para todas as bactérias. Apenas no 21º dia os peixes vacinados oralmente e por imersão apresentaram título de aglutinação superior aos peixes não vacinados para A. hidrophyla e E. durans. O soro dos peixes vacinados apresentou maior atividade antimicrobiana para P. aeroginosa e E. coli, do que os peixes não vacinados, nos dois períodos. As diferentes vias de administração da vacina estimularam a resposta hematológica e imunológica da tilápia do Nilo após 21 dias de vacinadas, sendo que o número total de leucócitos, linfócitos, título aglutinante do soro dos vacinados i.p. foi maior do que os demais.

The efficacy of a polyvalent bacterin vaccine against Aeromonas hydrophila, Pseudomonas aeroginosa and Enterococcus durans administered by different routes in Nile tilapia was assessed by analyzing hematological and immunological parameters 7 and 21 days after vaccination. Treatments consisted of: non-vaccinated tilapia; tilapia vaccinated by intraperitoneal injection with 2x10(8) formalin-inactivated bacteria·mL-1; tilapia vaccinated orally with 2x10(7) formalin-inactivated bacteria·g-1, feed for 5 days; tilapia vaccinated by immersion bath in 2x10(7) formalin-inactivated bacteria·mL-1, for 20 minutes. Vaccinated fish groups presented higher hematocrit, number of erythrocytes and leukocytes than the non-vaccinated group. Serum agglutination titer of intraperitoneally vaccinated fish was higher on both evaluation periods for the three bacteria strains. Only on day 21 post-vaccination fish from the oral and immersion vaccination groups presented higher serum agglutination titer than the non-vaccinated fish for A. hidrophyla and E. durans. Serum antimicrobial activity in vaccinated fish was higher for P. aeroginosa and E. coli than in non-vaccinated fish on both evaluation periods. The different vaccine administration routes stimulated hematological and immunological responses in Nile tilapia 21 days post-vaccination, but intraperitoneal vaccination presented higher total number of leukocytes, lymphocytes and serum agglutination titer.