Economic feasibility of probiotic use in the diet of Nile tilapia, Oreochromis niloticus, during the reproductive period

This work examines the economic advantages of probiotic use in the diet of Nile tilapia broodstock during the reproductive period. For this purpose, Bacillus subtilis was applied as a feed additive. The experimental design was completely randomized with three treatment groups: the T0 control (without probiotic), the T1 continuous probiotic intake, and the T2 alternate probiotic intake at a dose of 0.50 g kg-1 of feed (1010 CFU g-1 ) with four replicates. For the reproduction assay, 118 females and 48 males of Nile tilapia (proportion 4 males:9 females. hapa-1 ) (weight 527.65 g ± 185.98 g and length 30.16 cm ± 3.57 cm) were distributed into 12 hapas (3.5 × 2.0 × 1.5 m). Reproductive variables (spawning female percentage, egg production, and fry production) were used to calculate the economic feasibility indexes (total cost of nutrition [TcN], gross revenue [GR], and total operational profit [ToP]). The results show increasing values for spawning female number, collected eggs, and surviving fry in the probiotic groups. We recommend continuous intake of probiotic (feed with addition of probiotic) at a dose of 0.5 g kg-1 of feed (1010 CFU g-1 ) during the breeding season of Nile tilapia, due to the suitable reproductive indexes and profitability.(AU)

Economic feasibility of probiotic use in the diet of Nile tilapia, Oreochromis niloticus, during the reproductive period

This work examines the economic advantages of probiotic use in the diet of Nile tilapia broodstock during the reproductive period. For this purpose, Bacillus subtilis was applied as a feed additive. The experimental design was completely randomized with three treatment groups: the T0 control (without probiotic), the T1 continuous probiotic intake, and the T2 alternate probiotic intake at a dose of 0.50 g kg-1 of feed (1010 CFU g-1 ) with four replicates. For the reproduction assay, 118 females and 48 males of Nile tilapia (proportion 4 males:9 females. hapa-1 ) (weight 527.65 g ± 185.98 g and length 30.16 cm ± 3.57 cm) were distributed into 12 hapas (3.5 × 2.0 × 1.5 m). Reproductive variables (spawning female percentage, egg production, and fry production) were used to calculate the economic feasibility indexes (total cost of nutrition [TcN], gross revenue [GR], and total operational profit [ToP]). The results show increasing values for spawning female number, collected eggs, and surviving fry in the probiotic groups. We recommend continuous intake of probiotic (feed with addition of probiotic) at a dose of 0.5 g kg-1 of feed (1010 CFU g-1 ) during the breeding season of Nile tilapia, due to the suitable reproductive indexes and profitability.

Is hypoxia a stressor to American bullfrog tadpoles? / A hipóxia é um estressor para girinos de rã-touro?

The aim of this study was to evaluate alterations to the physiological profile of cortisol in pro-metamorphose phase tadpoles of Lithobates catesbeianus exposed to hypoxia stressor in a capture experiment and in a crowding experiment. The capture study was performed by the treatments: stress due to individual capture with a hand net, stress due to batch capture with a hand net and stress due to capture by emptying. Three simultaneous replicates was done witch 12 animals were sampled (6 normoxia - immediately blood collection) and 6 hypoxia - blood collection after 15 min of air exposition) in two collection times with 5 days by intervals. The crowding study was performed by the treatments 1 tadpole L-1, 5 tadpoles L-1 and 10 tadpoles L-1. Three simultaneous replicates was done witch 8 animals (4 normoxia and 4 hypoxia) were sampled in the zero moment (ZM) - blood collection before the experiment, 6 animals/treatment (3 normoxia and 3 hypoxia) to 4 and 8 days and 18 animals/treatment (9 normoxia and 9 hypoxia) to 12 days. The average values to plasmatic cortisol varying from 1.7 to 5.1ng mL-1 (capture study) and 1.0 to 4.2ng mL-1 (crowding study). It concludes that the biomarker tested (cortisol) showed no alterations front of the stressor used. Alternatively, a larger response pattern to these stimuli may have been expressed in another level of an unmeasured hormone (corticosterone). And the bullfrog has great ability to adapt to different management compared to other aquatic organisms, which demonstrates the plasticity of these animals.(AU)

Avaliou-se o cortisol em girinos de rã-touro (Lithobates catesbeianus), no estágio de pró-metamorfose ao mecanismo estressor de hipóxia juntamente com captura (1º experimento) e adensamento (2º experimento). O experimento de captura foi composto pelos tratamentos: Captura individual com puçá, Captura em massa com puçá e Captura por escoamento, com 3 réplicas simultâneas onde 12 organismos foram amostrados (6 normoxia - coleta imediata de sangue e 6 hipoxia - coleta de sangue após 15 min de exposição ao ar) em 2 tempos de coleta com intervalo de 5 dias. O experimento de densidade foi composto pelos tratamentos: 1 girino L-1, 5 girinos L-1 e 10 girinos L-1, com 3 réplicas simultâneas onde 8 animais (4 normoxia e 4 hipoxia) foram amostrados no momento zero (MZ) - coleta de sangue anterior ao experimento, 6 animais/tratamento (3 normoxia e 3 hipoxia) para 4 e 8 dias e 18 animais/tratamento (9 normoxia e 9 hipoxia) para 12 dias. Os valores médios para o cortisol plasmático foram de 1,7 a 5,1ng mL-1 (Experimento de Captura); e 1,0 a 4,2ng mL-1 (Experimento de Densidade). Conclui-se que o marcador biologico de estresse utilizado (cortisol) não foi alterado pelo agente extressor. Alternativamente a resposta a este estímulo pode ser expressa em outro nível hormonal (corticosterona). E a rã-touro apresenta ótima capacidade de se adaptar aos diferentes manejos se comparados a outros organismos aquáticos, o que demonstra a plasticidade destes animais.(AU)

Is hypoxia a stressor to American bullfrog tadpoles? / A hipóxia é um estressor para girinos de rã-touro?

The aim of this study was to evaluate alterations to the physiological profile of cortisol in pro-metamorphose phase tadpoles of Lithobates catesbeianus exposed to hypoxia stressor in a capture experiment and in a crowding experiment. The capture study was performed by the treatments: stress due to individual capture with a hand net, stress due to batch capture with a hand net and stress due to capture by emptying. Three simultaneous replicates was done witch 12 animals were sampled (6 normoxia - immediately blood collection) and 6 hypoxia - blood collection after 15 min of air exposition) in two collection times with 5 days by intervals. The crowding study was performed by the treatments 1 tadpole L-1, 5 tadpoles L-1 and 10 tadpoles L-1. Three simultaneous replicates was done witch 8 animals (4 normoxia and 4 hypoxia) were sampled in the zero moment (ZM) - blood collection before the experiment, 6 animals/treatment (3 normoxia and 3 hypoxia) to 4 and 8 days and 18 animals/treatment (9 normoxia and 9 hypoxia) to 12 days. The average values to plasmatic cortisol varying from 1.7 to 5.1ng mL-1 (capture study) and 1.0 to 4.2ng mL-1 (crowding study). It concludes that the biomarker tested (cortisol) showed no alterations front of the stressor used. Alternatively, a larger response pattern to these stimuli may have been expressed in another level of an unmeasured hormone (corticosterone). And the bullfrog has great ability to adapt to different management compared to other aquatic organisms, which demonstrates the plasticity of these animals.

Avaliou-se o cortisol em girinos de rã-touro (Lithobates catesbeianus), no estágio de pró-metamorfose ao mecanismo estressor de hipóxia juntamente com captura (1º experimento) e adensamento (2º experimento). O experimento de captura foi composto pelos tratamentos: Captura individual com puçá, Captura em massa com puçá e Captura por escoamento, com 3 réplicas simultâneas onde 12 organismos foram amostrados (6 normoxia - coleta imediata de sangue e 6 hipoxia - coleta de sangue após 15 min de exposição ao ar) em 2 tempos de coleta com intervalo de 5 dias. O experimento de densidade foi composto pelos tratamentos: 1 girino L-1, 5 girinos L-1 e 10 girinos L-1, com 3 réplicas simultâneas onde 8 animais (4 normoxia e 4 hipoxia) foram amostrados no momento zero (MZ) - coleta de sangue anterior ao experimento, 6 animais/tratamento (3 normoxia e 3 hipoxia) para 4 e 8 dias e 18 animais/tratamento (9 normoxia e 9 hipoxia) para 12 dias. Os valores médios para o cortisol plasmático foram de 1,7 a 5,1ng mL-1 (Experimento de Captura); e 1,0 a 4,2ng mL-1 (Experimento de Densidade). Conclui-se que o marcador biologico de estresse utilizado (cortisol) não foi alterado pelo agente extressor. Alternativamente a resposta a este estímulo pode ser expressa em outro nível hormonal (corticosterona). E a rã-touro apresenta ótima capacidade de se adaptar aos diferentes manejos se comparados a outros organismos aquáticos, o que demonstra a plasticidade destes animais.

Profile of cortisol, glycaemia, and blood parameters of American Bullfrog tadpoles Lithobates catesbeianus exposed to density and hypoxia stressors / Perfil de cortisol, glicemia, e parâmetros sanguineos de girinos de rã-touro Lithobates catesbeianus expostos a diferentes densidades e hipóxia

The aim of this study was to evaluate alterations to the physiological profile (cortisol, glycaemia, and blood parameters) of Lithobates catesbeianus caused by the stressors density and hypoxia. The organisms were in the prometamorphosis stage and exposed to different tadpole densities: 1 tadpole/L (T1), 5 tadpoles/L (T2), and 10 tadpoles/L (T3) for 12 days. The blood was collected through the rupture of the caudal blood vessel and collected under normoxia (immediate collection) and hypoxia (after 15 minutes of air exposure) conditions. Cortisol levels rose on the fourth and eighth days of treatment and returned to basal levels by the end of the experiment. The stressor mechanisms tested did not affect glycaemia. White blood cells (total number of lymphocytes, neutrophils, and eosinophils) showed a significant difference at the twelfth day of the experiment when compared with the start of the experiment. We concluded that, under controlled conditions, a density of up to 10 tadpoles/L and air exposure for 15 minutes did not cause harmful physiological alterations during the experimental period. The answer to these stressors maybe was in another hormonal level (corticosterone).(AU)

O objetivo deste estudo foi avaliar a resposta fisiológica (cortisol, glicemia e parâmetros sanguineos) de girinos de rã-touro (Lithobates catesbeianus) em diferentes densidades e após exposição aérea. Os animais utilizados no experimento estavam entre os estágios 31 a 39, na fase de pró-metamorfose sendo testados 1 girino/L (Tratamento 1), 5 girinos/L (Tratamento 2) e 10 girinos/L (Tratamento 3), conduzidos em 3 réplicas simultâneas durante 12 dias. O sangue foi retirado por rompimento do vaso caudal na condição de Normóxia - N (tempo zero) e Hipóxia - H (tempo de 15 minutos de exposição ao ar). Foi observado um aumento nos valores de cortisol, aos 4 e 8 dias de exposição aérea retornando aos valores basais ao final do experimento, apesar de não haver diferenças significativas. A glicemia não apresentou diferenças significativas quanto aos estressores aplicados. Os parâmetros hematológicos da série branca, principalmente, o número de linfócitos, neutrófilos e eosinófilos mostraram diferença significativa aos 12 dias de experimentação quando comparados com o momento zero; concluindo-se que, em condições controladas, o adensamento de até 10 girinos/litro e a exposição aérea por 15 minutos não apresentou danos aos girinos de rã-touro durante o período experimental. O padrão de resposta a estes estímulos talvez seja expresso em outro nível hormonal (corticosterona).(AU)

Profile of cortisol, glycaemia, and blood parameters of American Bullfrog tadpoles Lithobates catesbeianus exposed to density and hypoxia stressors / Perfil de cortisol, glicemia, e parâmetros sanguineos de girinos de rã-touro Lithobates catesbeianus expostos a diferentes densidades e hipóxia

The aim of this study was to evaluate alterations to the physiological profile (cortisol, glycaemia, and blood parameters) of Lithobates catesbeianus caused by the stressors density and hypoxia. The organisms were in the prometamorphosis stage and exposed to different tadpole densities: 1 tadpole/L (T1), 5 tadpoles/L (T2), and 10 tadpoles/L (T3) for 12 days. The blood was collected through the rupture of the caudal blood vessel and collected under normoxia (immediate collection) and hypoxia (after 15 minutes of air exposure) conditions. Cortisol levels rose on the fourth and eighth days of treatment and returned to basal levels by the end of the experiment. The stressor mechanisms tested did not affect glycaemia. White blood cells (total number of lymphocytes, neutrophils, and eosinophils) showed a significant difference at the twelfth day of the experiment when compared with the start of the experiment. We concluded that, under controlled conditions, a density of up to 10 tadpoles/L and air exposure for 15 minutes did not cause harmful physiological alterations during the experimental period. The answer to these stressors maybe was in another hormonal level (corticosterone).(AU)

O objetivo deste estudo foi avaliar a resposta fisiológica (cortisol, glicemia e parâmetros sanguineos) de girinos de rã-touro (Lithobates catesbeianus) em diferentes densidades e após exposição aérea. Os animais utilizados no experimento estavam entre os estágios 31 a 39, na fase de pró-metamorfose sendo testados 1 girino/L (Tratamento 1), 5 girinos/L (Tratamento 2) e 10 girinos/L (Tratamento 3), conduzidos em 3 réplicas simultâneas durante 12 dias. O sangue foi retirado por rompimento do vaso caudal na condição de Normóxia - N (tempo zero) e Hipóxia - H (tempo de 15 minutos de exposição ao ar). Foi observado um aumento nos valores de cortisol, aos 4 e 8 dias de exposição aérea retornando aos valores basais ao final do experimento, apesar de não haver diferenças significativas. A glicemia não apresentou diferenças significativas quanto aos estressores aplicados. Os parâmetros hematológicos da série branca, principalmente, o número de linfócitos, neutrófilos e eosinófilos mostraram diferença significativa aos 12 dias de experimentação quando comparados com o momento zero; concluindo-se que, em condições controladas, o adensamento de até 10 girinos/litro e a exposição aérea por 15 minutos não apresentou danos aos girinos de rã-touro durante o período experimental. O padrão de resposta a estes estímulos talvez seja expresso em outro nível hormonal (corticosterona).(AU)

Hematological parameters and phagocytic activity in fat snook (Centropomus parallelus) bred in captivity.

The objective of this work was to determine the hematological parameters and the phagocytic capacity of peritoneal macrophages of fat snook related to sex, stage of gonadal maturation and seasonal cycle. Blood was collected from 135 animals (78 females and 57 males) and used for determinations of: erythrocyte number, hematocrit, hemoglobin, erythrocyte indices mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), total and differential leukocyte counts, and thrombocyte count. The phagocytic capacity and phagocytic index were determined after Saccharomyces cerevisiae inoculation in the peritoneal cavity of the animals. The hematological results according to sex showed that the erythrocyte, total leukocyte and thrombocyte counts were statistically higher in males than females, with the latter showing a higher MCV. Concerning to erythrocyte count, hematocrit and hemoglobin concentration analyzed separately by sex and stage of gonadal maturation, males were found to have significantly elevated values in the mature stage and decreased levels in the resting stage. The results of the erythrocyte and leukocyte series, thrombocytes and phagocytic activity related to seasonal cycle showed significant differences in both sexes, where hematocrit and hemoglobin concentration were lower in winter and higher in the other seasons, mean corpuscular volume was higher in the summer and lower in the winter and fall, total leukocytes and thrombocytes lower in the spring and higher in the fall, lymphocytes low in the winter and summer and high in the spring and phagocytic capacity and phagocytic index high in the summer and low in the winter and fall. The results showed that the hematological values in males are statistically higher than those in females, the erythrocyte values in males increase with the progression of gonadal maturation and that winter is the season of the year least favorable for hematological and phagocytic responses for survival of fat snook kept in captivity. The parameters studied could be utilized in the evaluation of the health status of this species in captivity.

Acute toxicity of sodium selenite and sodium selenate to tilapia, Oreochromis niloticus, fingerlings / Toxicidade aguda de selenito e selenato de sódio para alevinos de tilápia, Oreochromis niloticus

Selenium is an essential nutrient for many organisms, including fish. It can be released in the water by natural processes of dissolving rocks and minerals, and by the wastewater from industries and agricultural activities, which can increase its concentration in the environment, leading to toxic effects to the aquatic biota. Median Lethal Concentrations (LC50-96h) of two forms of selenium were estimated to fingerlings of Nile tilapia Oreochromis niloticus, focusing on estimating indicators for future environmental risk assessments in aquatic ecosystems contaminated with those elements, particularly for evaluate sources of water quality suitable for rearing tilapia. The results were: LC50-96h of sodium selenite (Na2SeO3) = 4.42 mg Se4+ L-1, and LC50-96h of sodium selenate (Na2SeO4) = 14.67 mg Se6+ L-1. According to those data, it was possible to classify sodium selenite as highly toxic, and sodium selenate as moderately toxic to fingerlings of tilapia.

O selênio é um nutriente essencial para muitos organismos. Este sal pode ser liberado na água por processos naturais, pela dissociação de rochas e minerais, ou por restos de processos industriais e de atividades agrícolas, aumentando desta maneira sua concentração no ambiente, levando a efeitos tóxicos para a biota aquática. Concentrações Letais Medianas (CL50-96h) de duas formas de selênio foram estimadas para alevinos de tilápia-do-nilo, Oreochromis niloticus, com o intuito de estimar indicadores para futuras avaliações de risco ecotoxicológico em recursos hídricos contaminados com estes elementos, especialmente para avaliar as fontes de qualidade de água apropriadas para a tilapicultura. Os resultados obtidos foram: CL50-96h de selenito de sódio (Na2SeO3) = 4,42 mg Se4+ L-1, e CL50-96h de selenato de sódio (Na2SeO4) = 14,67 mg Se6+ L-1. A partir desses valores foi possível classificar o selenito de sódio como altamente tóxico e o selenato de sódio como moderadamente tóxico para alevinos de tilápia.

Use of probiotic in the diet of breeding matrinxã (Brycon amazonicus) / Utilização de probiótico na dieta de reprodutoras de matrinxã (Brycon amazonicus)

This study aimed to analyze the use of a probiotic (Bacillus subtilis) in the diet of breeding matrinxã (Brycon amazonicus), taking into account the number of oocytes, fertilization rate, hatching and final biomass. The experiment was carried out from March to November 2008. Fifty animals with mean weight 2.35 ± 0.31 kg and mean length 53.00 ± 1.96 cm were used in two treatments: T1 = control group and T2 = 10 g probiotic kg-1 food. The induced breeding was carried out with crude extract of carp pituitary. The result showed that the number of oocytes released, fertilization rate and hatching rates were 5%, 34% and 36% higher than in control group. The final total biomass of the control group was 3.6% higher compared to animals treated with probiotic, concluding that is viable to include Bacillus subtilis in diet of matrinxã for optimizing reproductive indicators.  

Objetivou-se avaliar a utilização de probiótico (Bacillus subtilis) na dieta de reprodutores de matrinxã (Brycon amazonicus), levando em consideração o número de ovócitos, taxa de fertilização, eclosão e biomassa final. O experimento foi realizado no período de março a novembro de 2008. Foram avaliados 50 animais com peso médio de 2,35 ± 0,31 kg e comprimento médio de 53,00 ± 1,96 cm. Utilizaram-se dois tratamentos, sendo T1 = grupo controle e T2 = 10 g de probiótico kg-1 de alimento. Realizou-se reprodução induzida com extrato bruto de hipófise de carpa. Observou-se que o número de ovócitos liberados e as taxas de fertilização e eclosão foram 5%, 34% e 36% superiores nos animais alimentados com o probiótico. A biomassa final total do grupo controle foi 3,6% superior em relação aos animais tratados com probiótico. Concluiu-se que é viável a utilização do Bacillus subtilis na alimenação de matrizes de matrinxã para otimização de indicadores reprodutivos.

Use of probiotic in the diet of breeding matrinxã (Brycon amazonicus) / Utilização de probiótico na dieta de reprodutoras de matrinxã (Brycon amazonicus)

This study aimed to analyze the use of a probiotic (Bacillus subtilis) in the diet of breeding matrinxã (Brycon amazonicus), taking into account the number of oocytes, fertilization rate, hatching and final biomass. The experiment was carried out from March to November 2008. Fifty animals with mean weight 2.35 ± 0.31 kg and mean length 53.00 ± 1.96 cm were used in two treatments: T1 = control group and T2 = 10 g probiotic kg-1 food. The induced breeding was carried out with crude extract of carp pituitary. The result showed that the number of oocytes released, fertilization rate and hatching rates were 5%, 34% and 36% higher than in control group. The final total biomass of the control group was 3.6% higher compared to animals treated with probiotic, concluding that is viable to include Bacillus subtilis in diet of matrinxã for optimizing reproductive indicators.

Objetivou-se avaliar a utilização de probiótico (Bacillus subtilis) na dieta de reprodutores de matrinxã (Brycon amazonicus), levando em consideração o número de ovócitos, taxa de fertilização, eclosão e biomassa final. O experimento foi realizado no período de março a novembro de 2008. Foram avaliados 50 animais com peso médio de 2,35 ± 0,31 kg e comprimento médio de 53,00 ± 1,96 cm. Utilizaram-se dois tratamentos, sendo T1 = grupo controle e T2 = 10 g de probiótico kg-1 de alimento. Realizou-se reprodução induzida com extrato bruto de hipófise de carpa. Observou-se que o número de ovócitos liberados e as taxas de fertilização e eclosão foram 5%, 34% e 36% superiores nos animais alimentados com o probiótico. A biomassa final total do grupo controle foi 3,6% superior em relação aos animais tratados com probiótico. Concluiu-se que é viável a utilização do Bacillus subtilis na alimenação de matrizes de matrinxã para otimização de indicadores reprodutivos.

Acute toxicity of sodium selenite and sodium selenate to tilapia, Oreochromis niloticus, fingerlings / Toxicidade aguda de selenito e selenato de sódio para alevinos de tilápia, Oreochromis niloticus

Selenium is an essential nutrient for many organisms, including fish. It can be released in the water by natural processes of dissolving rocks and minerals, and by the wastewater from industries and agricultural activities, which can increase its concentration in the environment, leading to toxic effects to the aquatic biota. Median Lethal Concentrations (LC50-96h) of two forms of selenium were estimated to fingerlings of Nile tilapia Oreochromis niloticus, focusing on estimating indicators for future environmental risk assessments in aquatic ecosystems contaminated with those elements, particularly for evaluate sources of water quality suitable for rearing tilapia. The results were: LC50-96h of sodium selenite (Na2SeO3) = 4.42 mg Se4+ L-1, and LC50-96h of sodium selenate (Na2SeO4) = 14.67 mg Se6+ L-1. According to those data, it was possible to classify sodium selenite as highly toxic, and sodium selenate as moderately toxic to fingerlings of tilapia.

O selênio é um nutriente essencial para muitos organismos. Este sal pode ser liberado na água por processos naturais, pela dissociação de rochas e minerais, ou por restos de processos industriais e de atividades agrícolas, aumentando desta maneira sua concentração no ambiente, levando a efeitos tóxicos para a biota aquática. Concentrações Letais Medianas (CL50-96h) de duas formas de selênio foram estimadas para alevinos de tilápia-do-nilo, Oreochromis niloticus, com o intuito de estimar indicadores para futuras avaliações de risco ecotoxicológico em recursos hídricos contaminados com estes elementos, especialmente para avaliar as fontes de qualidade de água apropriadas para a tilapicultura. Os resultados obtidos foram: CL50-96h de selenito de sódio (Na2SeO3) = 4,42 mg Se4+ L-1, e CL50-96h de selenato de sódio (Na2SeO4) = 14,67 mg Se6+ L-1. A partir desses valores foi possível classificar o selenito de sódio como altamente tóxico e o selenato de sódio como moderadamente tóxico para alevinos de tilápia.