RESUMO
In this study, we analyzed the hematoimmunological effects of dietary supplementation with immunomodulators (ß-glucans + nucleotides) and different levels of vitamins on Nile tilapia (Oreochromis niloticus) after exposure to physical stress. The following four diet treatments were used: diets with indicated vitamin levels (Vitind), diets with Vitind + immunomodulator (Vitind + Immune), diets with high vitamin content (Vithigh), and those with Vithigh + immunomodulator (Vithigh + Immune). The experiment included 560 fish in 28 tanks (20 fish tank-1), with seven replicates per treatment. After 60 days of supplementation, the water temperature was set at 20 °C, and complete biometrics were performed. The animals were then subjected to physical stress with temperature oscillations of 20 ºC to 30 ºC/30 ºC to 20 ºC/20 ºC to 30 ºC. Hematoimmunological data from 140 animals were collected post-stress. Antimicrobial titer and total plasma protein levels were significantly higher in fish not receiving immunomodulator-supplemented diets (2.88 ± 0.43 log2 and 26.81 ± 4.01 mgâmL-1, respectively) than in those that did. Conversely, the agglutination titer increased in fish fed with lower vitamin levels (3.33 ± 0.66 log2) compared to those with higher vitamin levels. Increased immunoglobulin levels were observed in fish fed diets co-supplemented with vitamins and immunomodulators, revealing an interaction between immunomodulators and dietary vitamin levels. In summary, the inclusion of immunomodulators in the diet enhanced the animals' resistance to physical stress and improved hematoimmunological parameters. Additionally, a high vitamin content in the diet did not modulate the immune responses in the animals.
Neste estudo analisamos os efeitos hematoimunológicos da suplementação dietética com imunomoduladores (ß-glucanos+nucleotídeos) e diferentes níveis de vitaminas na tilápia do Nilo (Oreochromis niloticus) após exposição ao estresse físico. Foram utilizados quatro tratamentos: dietas com níveis indicados de vitaminas (Vitind), dietas com Vitind + imunomodulador (Vitind+Immune), dietas com alto teor de vitaminas (Vithigh) e dietas com Vithigh + imunomodulador (Vithigh+Immune). O experimento incluiu 560 peixes em 28 tanques (20 peixes tanques-1), com sete repetições por tratamento. Após 60 dias de suplementação, a temperatura da água foi fixada em 20 °C e realizada biometria completa. Os animais foram submetidos a estresse físico com oscilações de temperatura de 20 ºC a 30 ºC/30 ºC a 20 ºC/20 ºC a 30 ºC. Dados hematoimunológicos de 140 animais foram coletados pós-estresse. O título antimicrobiano e os níveis de proteína plasmática total foram significativamente maiores em peixes que não receberam dietas com imunomodulador (2,88±0,43 log2 e 26,81±4,01 mgâmL−1) do que naqueles que receberam. Por outro lado, o título de aglutinação aumentou em peixes alimentados com níveis mais baixos de vitaminas (3,33±0,66 log2) comparado àqueles com níveis mais elevados. Níveis aumentados de imunoglobulinas foram observados em peixes alimentados com dietas co-suplementadas com vitaminas e imunomoduladores, revelando interação entre imunomoduladores e níveis de vitaminas na dieta. Em resumo, a inclusão de imunomoduladores na dieta aumentou a resistência dos animais ao estresse físico e melhorou os parâmetros hematoimunológicos. Além disso, o alto teor de vitaminas na dieta não modulou as respostas imunológicas dos animais.
RESUMO
The study evaluated dietary supplementation with a feed additive composed of multi-strain Bacillus for Nile tilapia Oreochromis niloticus. In vitro and in vivo assays employing culture-based microbiological methods and metagenomics were performed. Additionally, the study assessed the haemato-immunology, intestinal microbiome, and growth performance of the animals. For this, 30 juvenile Nile tilapia were used in the in vitro assay and 180 (60 + 120) in the in vivo assays. In the in vitro assay, we found evidence of adhesion of the probiotic bacteria to the intestinal mucus of fish, corroborated in the 15-day in vivo assay, in which the count of B. licheniformis was significantly higher in fish fed with probiotic when compared to fish of the control group. Furthermore, in the 50-day in vivo trial, a metagenomic analysis provided evidence for the modulation of the intestine microbiome of Nile tilapia by dietary supplementation of the probiotic. In addition, there was an increase in species richness, higher abundance of potentially probiotic autochthonous species and a lower abundance of Aeromonas sp. when the animals were fed the supplemented diet. Finally, no significant differences were observed in growth performance and haemato-immunological analyses, suggesting no harm to fish health when the product was supplemented for 15 and 50 days. The in vitro results indicate that the multi-strain probiotics were able to adhere to the intestinal mucus of Nile tilapia. Additionally, a modulation of the intestinal microbiome was evidenced in the in vivo assay.
Assuntos
Ração Animal , Bacillus , Ciclídeos , Dieta , Microbioma Gastrointestinal , Probióticos , Animais , Probióticos/farmacologia , Probióticos/administração & dosagem , Ciclídeos/imunologia , Ciclídeos/crescimento & desenvolvimento , Ciclídeos/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Ração Animal/análise , Dieta/veterinária , Suplementos Nutricionais/análiseRESUMO
Laboratory-reared early juveniles (48 days after hatching) of the common snook (Centropomus undecimalis) were fed for 30 days using three different diets in order to evaluate transition from live to inert diet (weaning): 1) an experimental dry diet (46% crude protein), 2) a commercial dry diet (57% crude protein), and 3) only enriched Artemia metanauplii, used as a control group. The fish were placed in 80 L cylindrical tanks (three replicates) equipped with aeration and flow-through water (34 ± 1 salinity), and kept at 26.0 ± 0.5°C. The specific growth rates obtained in treatments 1 (5.62% day-1) and 2 (6.13% day-1) were similar (P = 0.32) and higher than the specific growth rate verified in the control group (3.71% day-1) (P = 0.002). The feed conversion ratio was more efficient with the commercial diet (0.85 ± 0.04) when compared to the experimental diet (1.41 ± 0.15) (P = 0.003). There were no significant differences among the survival rates observed in the different treatments (P = 0.05) with values of 61.00 ± 1.00%, 83.66 ± 5.77% and 77.33 ± 14.57% for experimental, commercial and control diets, respectively. This study demonstrates that the inert diets tested were appropriate for weaning the common snook early juveniles.
Juvenis de robalo-flecha (Centropomus undecimalis) cultivados em laboratório, com 48 dias após a eclosão, foram alimentados por 30 dias, a fim de avaliar a melhor dieta na transição do alimento vivo para o inerte, com três diferentes tratamentos: 1) dieta experimental (46% de proteína bruta), 2) dieta comercial (57% de proteína bruta) e 3) somente metanáuplios de Artemia enriquecidos (grupo controle). Os peixes foram mantidos em tanques cilíndricos de 80 L (três réplicas) equipados com aeração e fluxo contínuo de água (34 ± 1 de salinidade), mantida a 26,0 ± 0,5°C. As taxas de crescimento específico nos tratamentos 1 (5,62% dia-1) e 2 (6,13% dia-1) foram similares (P = 0,32) e superiores à taxa de crescimento específico verificada no grupo controle (3,71% dia-1) (P = 0,002). A conversão alimentar foi maior nos peixes que receberam a dieta comercial (0,85 ± 0,04) que naqueles com dieta experimental (1,41 ± 0,15) (P = 0,003). Não houve diferença para a sobrevivência nos diferentes tratamentos (P = 0,05), com valores de 61,00 ± 1,00%; 83,66 ± 5,77% e 77,33 ± 14,57%, para os tratamentos experimental, comercial e controle respectivamente. O estudo demonstra que as duas dietas testadas são apropriadas para substituir o alimento vivo no desmame de juvenis de robalo-flecha.
RESUMO
Laboratory-reared early juveniles (48 days after hatching) of the common snook (Centropomus undecimalis) were fed for 30 days using three different diets in order to evaluate transition from live to inert diet (weaning): 1) an experimental dry diet (46% crude protein), 2) a commercial dry diet (57% crude protein), and 3) only enriched Artemia metanauplii, used as a control group. The fish were placed in 80 L cylindrical tanks (three replicates) equipped with aeration and flow-through water (34 ± 1 salinity), and kept at 26.0 ± 0.5°C. The specific growth rates obtained in treatments 1 (5.62% day-1) and 2 (6.13% day-1) were similar (P = 0.32) and higher than the specific growth rate verified in the control group (3.71% day-1) (P = 0.002). The feed conversion ratio was more efficient with the commercial diet (0.85 ± 0.04) when compared to the experimental diet (1.41 ± 0.15) (P = 0.003). There were no significant differences among the survival rates observed in the different treatments (P = 0.05) with values of 61.00 ± 1.00%, 83.66 ± 5.77% and 77.33 ± 14.57% for experimental, commercial and control diets, respectively. This study demonstrates that the inert diets tested were appropriate for weaning the common snook early juveniles.
Juvenis de robalo-flecha (Centropomus undecimalis) cultivados em laboratório, com 48 dias após a eclosão, foram alimentados por 30 dias, a fim de avaliar a melhor dieta na transição do alimento vivo para o inerte, com três diferentes tratamentos: 1) dieta experimental (46% de proteína bruta), 2) dieta comercial (57% de proteína bruta) e 3) somente metanáuplios de Artemia enriquecidos (grupo controle). Os peixes foram mantidos em tanques cilíndricos de 80 L (três réplicas) equipados com aeração e fluxo contínuo de água (34 ± 1 de salinidade), mantida a 26,0 ± 0,5°C. As taxas de crescimento específico nos tratamentos 1 (5,62% dia-1) e 2 (6,13% dia-1) foram similares (P = 0,32) e superiores à taxa de crescimento específico verificada no grupo controle (3,71% dia-1) (P = 0,002). A conversão alimentar foi maior nos peixes que receberam a dieta comercial (0,85 ± 0,04) que naqueles com dieta experimental (1,41 ± 0,15) (P = 0,003). Não houve diferença para a sobrevivência nos diferentes tratamentos (P = 0,05), com valores de 61,00 ± 1,00%; 83,66 ± 5,77% e 77,33 ± 14,57%, para os tratamentos experimental, comercial e controle respectivamente. O estudo demonstra que as duas dietas testadas são apropriadas para substituir o alimento vivo no desmame de juvenis de robalo-flecha.