Predation rate of dragonfly (Odonata: Libellulidae) on tilapia (Oreochromis niloticus Linnaeus 1758) and the availability of alternative preys (Insecta: Diptera: Chironomidae) to increase fish survival

The objective of this work was to evaluate the predation rates of two genera of Odonata Miathyria Kirby, 1889 and Erythemis Hagen, 1861 in post-larviculture of tilapia with and without availability of Chironomidae. For that, 3 experiments were carried out, the first to analyze which size scale of these two genera would be more efficient in the predation of tilapia and the other 2 experiments with the selected size scales, to analyze the predation rates on tilapia with different Odonata densities, with and without availability of the aquatic insect Chironomidae. For statistical analysis of the data, an analysis of variance (ANOVA) was applied with the Duncan test searching for the means in all experiments. In experiments 2 and 3 a linear regression model was also applied. In experiment 1, there were significant differences between treatments, and in the phase with Miathyria the predation of tilapia post-larvae was higher among odonates that corresponded to the size scale from 7.1 to 9.9 mm and therefore the scale was also selected for the next experiments. For Erythemis, the consumption of tilapia was higher in the size scale between 12.1 to 14,2 mm. In the following experiments, there were significant differences between treatments. With the increase in Odonata densities the predation of the fish was greater. With the availability of Chironomidae, the consumption of tilapia post-larvae decreased. The consumption of Chironomidae was higher than the consumption of fish in experiment 3. Miathyria proved to be more efficient than Erythemis in predation and the use of Chironomidae can be a sustainable alternative for post-larvae predation control on fish farms.(AU)

Effect of feeding frequency and water salinization on early development of Pyrrhulina brevis, an Amazonian ornamental fish / Efeito da frequência alimentar e da salinização da água sobre o desenvolvimento inicial de Pyrrhulina brevis, um peixe ornamental da Amazônia

Pyrrhulina brevis is an endemic fish from the Amazon basin that is valued in the ornamental fish market. In larviculture, fish are very sensitive to stressors and have a high mortality rate. Salinized water may provide more energy to overcome stress and feeding frequency is an important strategy to improve productive performance. Therefore, the aim of this study was to evaluate the best feeding frequency and the best level of water salinization for larval development of P. brevis. A total of 360 post-larvae of P. brevis (5.26 ± 1.65 mg, 5.57 ± 0.68 mm) were randomly distributed in 36 aquariums (1 L) in a 3x4 factorial scheme, to evaluate three concentrations of salt in water (0, 1 and 2 g L-1) and four feeding frequencies (once, twice, three and four times a day). We offered 150 Artemia nauplii per day and per post-larvae during 15 days. The fish kept at 1 g L-1 salinized water, and those fed 3 and 4 times a day presented significantly greater final length and weight, weight gain, and specific growth rate for length and weight. An interaction between salinized water and feeding frequency was observed for survival rate. We conclude that, during the initial rearing phase of P. brevis, feeding frequency of three times a day and salinized water at 1 g L-1 is recommended.(AU)

Pyrrhulina brevis é um peixe endêmico da bacia amazônica que apresenta bons valores no mercado de peixes ornamentais. Na larvicultura, os peixes são muito sensíveis aos estressores e apresentam alta taxa de mortalidade. A água salinizada pode fornecer mais energia para superar o estresse e a frequência alimentar é uma estratégia importante para melhorar o desempenho produtivo. Portanto, o objetivo deste trabalho foi avaliar a melhor frequência alimentar e o melhor nível de salinização da água para o desenvolvimento larval de P. brevis. Um total de 360 pós-larvas de P. brevis (5,26 ± 1,65 mg, 5,57 ± 0,68 mm) foram distribuídos aleatoriamente em 36 aquários (1 L) em esquema fatorial 3x4, para avaliar três concentrações de sal na água (0, 1 e 2 g L-1) e quatro frequências de alimentação (uma, duas, três e quatro vezes ao dia). Foram oferecidas 150 náuplios de Artemia por dia e por pós-larva, durante 15 dias. Os peixes mantidos com 1 g L-1 de água salinizada e os alimentados 3 e 4 vezes ao dia apresentaram comprimento e peso finais, ganho de peso e taxa de crescimento específico para comprimento e peso significativamente maiores. Uma interação entre água salinizada e frequência alimentar foi observada para a taxa de sobrevivência. Concluímos que, durante a fase inicial de criação de P. brevis, recomenda-se uma frequência alimentar de três vezes ao dia e água salinizada a 1 g L-1.(AU)

Salinized water as a strategy for increase stocking density in Heros severus larviculture, an Amazonian ornamental fish / Água salinizada como estratégia para aumentar a densidade de estocagem na larvicultura de Heros severus, um peixe ornamental da Amazônia

The aim of this study was to evaluate the effect of different salinized water (0, 3 and 6 g L-1) and sto-cking densities (10, 15 and 20 larvae L-1) in Heros severus larviculture. The experimental design was completely randomized, in a 3x3 factorial design, with three replicates. For this, a total of 405 larvae of H. severus were randomly distributed in 27 aquariums (1L) according to the treatments and after 15 days all the larvae were measured, weighed and counted. Higher values for final length, length gain and specific growth rate were observed in H. severus larvae raised at any stocking density tested at 3 g L-1 of salinized water (p < 0.05). The final weight and weight gain followed the same trend of the length, being higher in fish submitted to 3 g L-1 of salinized water (p < 0.05). On the other hand, the salinized water of 6 g L-1 was detrimental to larvae weight uniformity and survival rate (p < 0.05). The fish stocked at densities of 15 or 20 larvae L-1 presented the best results of final weight and weight gain (p < 0.05). The stocking density of 20 larvae L-1 in salinized water at 3 g L-1 is recommended for H. severus larviculture.(AU)

O objetivo deste trabalho foi avaliar o efeito de diferentes águas salinizadas (0, 3 e 6 g L-1) e densidades de estocagem (10, 15 e 20 larvas L-1) na larvicultura de Heros severus. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 3x3, com três repetições. Para isso, 405 larvas de H. severus foram distribuídas aleatoriamente em 27 aquários (1 L), de acordo com os tratamentos e, 15 dias depois, todas foram medidas, pesadas e contadas. Maiores valores de comprimento final, ganho de comprimento e taxa de crescimento específico foram observados em larvas criadas em qualquer densidade testada a 3 g L-1 de água salinizada (p < 0,05). O peso final e o ganho de peso seguiram a ten-dência do comprimento, sendo maiores nos peixes submetidos a 3 g L-1 de água salinizada (p < 0,05). Por outro lado, a água salinizada a 6 g L-1 prejudicou a uniformidade do peso e a taxa de sobrevivência das larvas (p < 0,05). Os peixes estocados nas densidades de 15 ou 20 larvas L-1 apresentaram os me-lhores resultados de peso final e ganho de peso (p < 0,05). A densidade de estocagem de 20 larvas L-1 em água salinizada a 3 g L-1 é recomendada para a larvicultura de H. severus.(AU)

Pirarucu larviculture in green water provides heavier fish and modulates locomotor activity / Larvicultura de pirarucu em água verde produz peixes mais pesados e modula a atividade locomotora

The green water technique uses microalgae in the water of indoor larviculture, providing a darker environment to favor fish growth, welfare and health. We evaluated growth performance and locomotor activity after light exposure of pirarucu (Arapaima gigas) larvae reared in green or clear water. During one test, pirarucu larvae (3.6 ± 0.3 cm; 0.36 ± 0.1 g) were reared in 50-L circular tanks (n = 3 per treatment, 50 larvae per tank) in a static system containing green water [microalgae (w3algae; Bernaqua® 10 g m-3) added] or clear water (control). Fish weaning was achieved by co-feeding with Artemia nauplii and microdiets for seven days until full microdiet substitution. Larvae were biometrically evaluated on days 10, 17 and 24 to assess growth performance. In a second test, the locomotor activity of the larvae was analyzed before and after light exposure (1400 ± 60 lx) for 48 h according to an ethogram. After 24 days, the larvae reared in the green water were significantly heavier than those from the clear water, and displayed significantly fewer circular swimming movements. Body cortisol increased in both groups after light exposure. The microalgae provided an additional food source for larvae, with positive impact on growth until day 17 of larviculture. Green water can be a strategy to achieve better results in pirarucu larviculture, especially during and up to 10 days after the co-feeding period.(AU)

A técnica de água verde utiliza microalgas na água durante a larvicultura indoor, proporcionando um ambiente mais escuro que favorece o crescimento, bem-estar e saúde dos peixes. Avaliamos o crescimento e a atividade locomotora após exposição à luz de larvas de pirarucu (Arapaima gigas) criadas em água verde ou clara. Em um teste, larvas de pirarucu (3,6 ± 0,3 cm; 0,36 ± 0,1 g) foram criadas em tanques circulares de 50 L (n = 3 por tratamento; 50 larvas por tanque) em sistema estático contendo água verde [microalgas (w3algae; Bernaqua® 10 g m-3) adicionadas] ou água clara (controle). A transição alimentar dos peixes ocorreu por co-alimentação com náuplios de Artemia e microdieta por sete dias até a substituição completa pela microdieta. A biometria das larvas foi avaliada nos dias 10, 17 e 24, para avaliar o crescimento. Um segundo teste avaliou a atividade locomotora das larvas antes e após exposição à luz (1.400 ± 60,47 lx) por 48 horas usando um etograma. Após 24 dias, os peixes criados em água verde pesaram significativamente mais que os da água clara, e apresentaram significativamente menos movimentos circulares de natação. A exposição à luz aumentou o cortisol corporal nos dois grupos depois da exposição à luz. O nível corporal de cortisol aumentou em ambos grupos após exposição à luz. As microalgas forneceram uma fonte adicional de alimento para as larvas, com impacto positivo sobre seu crescimento até o 17º dia de larvicultura. Água verde pode ser uma estratégia para obter melhores resultados na larvicultura de pirarucu, principalmente durante e até 10 dias após o período de co-alimentação.(AU)

Selenium supplementation levels and sources in postlarvae Nile tilapia diet / Níveis de suplementação e Fontes de Selênio na Dieta de pós-larvas de Tilápia do Nilo

Fish larviculture exert great influence in the subsequent phases, in which nutrition is a basic prerequisite for success. Therefore, when it is in an intensified production system, it promotes the limitation of some minerals, making it necessary to supplement selenium in diets for post-larvae. The objective of this study was to evaluate selenium levels and sources in post-larvae Nile tilapia diets on muscle performance and histology. A total of 1,260 post-larvae with an initial average weight of 0.010 g were used, distributed in a completely randomized design in a factorial scheme with four supplementation levels (0.6; 0.9; 1.2 and 1.5 mg of Se/Kg) and two sources (sodium selenite and selenium yeast), plus the negative control, with 35 post-larvae Nile tilapia used per experimental unit. The physical-chemical parameters of water quality were within those recommended for tilapia cultivation. Feed consumption (p < 0.05) and hepatosomatic index (p < 0.05) were affected by the source used. Effects of supplemented selenium levels and sources were not observed for the other performance variables. Higher values for final height, final width, specific development rate and protein efficiency rate were found (p < 0.05) when comparing the control diet with diets containing the sodium selenite source. No effects on muscle fiber morphometry were observed (p > 0.05) in the studied variables. It is concluded that 0.6 mg of selenium in the diet, regardless of the source used, met the mineral requirement for post-larvae Nile tilapia.(AU)

A larvicultura de peixes exerce grande influência nas fases subsequentes, onde a nutrição é um prérequisito básico para o sucesso. Portanto, quando está em sistema de produção intensificada, promove a limitação de alguns minerais, sendo necessária a suplementação de selênio em dietas para pós-larvas. Objetivou-se avaliar níveis e fontes de selênio em dietas para pós-larvas de tilápia do Nilo, sobre o desempenho e histologia muscular. Utilizou-se 1260 pós-larvas, peso médio inicial 0,010 g, distribuídas em delineamento inteiramente casualizado, em esquema fatorial com quatro níveis de suplementação (0,6; 0,9; 1,2 e 1,5 mg/kg de Selênio) e duas fontes (Selenito de sódio e Selênio levedura), mais o controle negativo, utilizou-se 35 pós-larvas por unidade experimental. Os parâmetros físico-químicos de qualidade da água, apresentaram-se dentro do recomendado para tilápias. O consumo de ração (p < 0001) e índice hepatossomático (p < 0,05), foram afetados pela fonte utilizada. Para as demais variáveis de desempenho, não foram observados efeitos dos níveis e das fontes de selênio suplementadas. Quando comparada dieta controle as dietas contendo a fonte selenito de sódio verificou-se (p < 0,05) maiores altura final, largura final, taxa de desenvolvimento especifico e taxa de eficiência proteica. Não foram evidenciados (p > 0,05) efeitos sobre morfometria das fibras musculares nas variáveis estudadas. Conclui-se que 0,6mg de selênio na dieta, independente da fonte utilizada atendeu a necessidade do mineral para pós-larvas de tilápia do Nilo.(AU)

Salinity and prey concentration on larviculture of killifish Hypsolebias radiseriatus (Cyprinodontiformes: Rivulidae)

The aim of this study was to investigate the tolerance of Hypsolebias radiseriatuslarvae to different salinities, and the effects of different prey concentrations and water salinities on the larviculture of this species. Salinity tolerance was tested by subjecting newly-hatched larvae to 96 hours of osmotic shock testing (experiment I) and gradual acclimatization (experiment II) of the following salinities: freshwater (control), 2, 4, 6 and 8 g of salt L-1. A third experiment (experiment III) evaluated three water salinities (S0-freshwater, S2-2 g of salt L-1and S4–4 g of salt L-1) and three initial daily prey concentrations (100, 300 and 500 artemia nauplii larva-1). In experiments I and II, survival was only influenced by the salinity of 8 g of salt L-1(p < 0.01). After 35 days, weight was only influenced by prey concentration (p < 0.05), with the highest value being with 500 artemia nauplii larva-1. The lowest survival was for 4 g of salt L-1and for 100 artemia nauplii larva-1. H. radiseriatuslarviculture can be carried out in salinity of up to 2 g of salt L-1and initial daily prey concentrations with 500 artemia nauplii larva-1.(AU)

Salinity and prey concentration on larviculture of killifish Hypsolebias radiseriatus (Cyprinodontiformes: Rivulidae)

The aim of this study was to investigate the tolerance of Hypsolebias radiseriatuslarvae to different salinities, and the effects of different prey concentrations and water salinities on the larviculture of this species. Salinity tolerance was tested by subjecting newly-hatched larvae to 96 hours of osmotic shock testing (experiment I) and gradual acclimatization (experiment II) of the following salinities: freshwater (control), 2, 4, 6 and 8 g of salt L-1. A third experiment (experiment III) evaluated three water salinities (S0-freshwater, S2-2 g of salt L-1and S4–4 g of salt L-1) and three initial daily prey concentrations (100, 300 and 500 artemia nauplii larva-1). In experiments I and II, survival was only influenced by the salinity of 8 g of salt L-1(p < 0.01). After 35 days, weight was only influenced by prey concentration (p < 0.05), with the highest value being with 500 artemia nauplii larva-1. The lowest survival was for 4 g of salt L-1and for 100 artemia nauplii larva-1. H. radiseriatuslarviculture can be carried out in salinity of up to 2 g of salt L-1and initial daily prey concentrations with 500 artemia nauplii larva-1.

Sex reversal in siamese fighting fish larvae by thermal management / Inversão sexual de larvas de betta por manipulação térmica

The present study evaluated the influence of thermal management during the larviculture of Betta splendens on survival and sex ratio, aiming to increase the proportion of males. Newly hatched larvae were subjected to different thermal regimes, namely, T25, T28, T30 and T33 (25, 28, 30 and 33°C, respectively). The experiment was laid out in a completely randomized design, with 4 treatments and 10 repetitions. Thermal treatment was maintained until 15 days post-hatch (DPH). Mortality was determined at the end of the thermal regime and again at 45 DPH. At the end of the experiment, the number of males and females obtained in the different thermal treatments was counted to analyze the obtained sex ratio. There was a significant effect on mortality as a function of temperature only at 15 DPH (p <0.001), with the lowest values recorded in treatments T25, T28 and T30. In terms of sex ratio, up to 65% of males were obtained in treatment T33 (p = 0.037). In conclusion, thermal management during the larval period can be a strategy to increase the proportion of males, but the increase in mortality due to the rise in temperature should be considered.

O presente estudo avaliou a influência da manipulação térmica durante a larvicultura de Betta splendens na sobrevivência e razão sexual, buscando aumento na proporção de machos. Larvas recém-eclodidas foram submetidas a diferentes regimes térmicos, denominados: T25, T28, T30 e T33 (25, 28, 30 e 33°C, respectivamente). Seguiu-se um delineamento inteiramente casualizado, com 4 tratamentos e 10 repetições. O tratamento termal foi mantido até os 15 DPE (dias pós-eclosão). No encerramento do regime termal e novamente aos 45 DPE foi contabilizada a mortalidade. No final do experimento foi contabilizado o número de machos e fêmeas obtidos nos diferentes tratamentos térmicos para análise da proporção sexual obtida. Houve efeito significativo da mortalidade em função da temperatura apenas aos 15 DPE (p <0,001) e os tratamentos T25, T28 e T30 apresentaram os menores valores para tal parâmetro. Para a razão sexual, foram obtidos até 65% de machos no tratamento T33 (p = 0,037). Conclui-se que a manipulação termal durante o período larval pode ser uma estratégia para o aumento da proporção de machos, considerando o aumento da mortalidade em função da elevação da temperatura.

Post-larval Colossoma macropomum (Characiformes, Serrasalmidae) show better performance in excavated than concrete tanks under different feeding strategies

As the global human population increases, the demand for food grows and, consequently, practices such as aquaculture have become more common. Colossoma macropomum (Cuvier, 1818) is a native Amazonian species, considered to be the second most cultivated fish in the country. We compared the development of post-larval C. macropomum of different ages, submitted to combinations of food management on a commercial production scale. Two experiments tested the delivery of i) 55% crude protein feeding, ii) natural feeding by fertilizing the water and iii) a combination of both during hatchery in concrete tanks (10 m 2) or excavated soil-bottom tanks (4502) subjected to distinct fertilization protocols and storage densities. The weight and length of the post-larvae grown in ponds were greater (p < 2.0x10-16) for the mixed treatment, except during the first week of larvae, in which values were similar (p & 8804; 1.76x10-14) to the fertilization treatment. Concrete tanks with fertilization management without feeding were similar to the mixed treatment (p & 8804; 1.38x10-7); however, during the first week of external larvae production, the growth performance under fertilization treatment was superior to the others. Food management in excavated tanks, when compared to the same management performed in concrete tanks, registered higher averages for the productive variables of C. macropomum cultivated at the density of 200 post-larvae m-2 in all evaluated food strategies. It was verified that post-larvae of C. macropomum did not develop well in the first weeks of life when receiving only formulated diets. The increase in natural food availability through fertilization positively influenced the performance of the species, which can remain without feeding until the second week of life.

Sex reversal in siamese fighting fish larvae by thermal management / Inversão sexual de larvas de betta por manipulação térmica

The present study evaluated the influence of thermal management during the larviculture of Betta splendens on survival and sex ratio, aiming to increase the proportion of males. Newly hatched larvae were subjected to different thermal regimes, namely, T25, T28, T30 and T33 (25, 28, 30 and 33°C, respectively). The experiment was laid out in a completely randomized design, with 4 treatments and 10 repetitions. Thermal treatment was maintained until 15 days post-hatch (DPH). Mortality was determined at the end of the thermal regime and again at 45 DPH. At the end of the experiment, the number of males and females obtained in the different thermal treatments was counted to analyze the obtained sex ratio. There was a significant effect on mortality as a function of temperature only at 15 DPH (p <0.001), with the lowest values recorded in treatments T25, T28 and T30. In terms of sex ratio, up to 65% of males were obtained in treatment T33 (p = 0.037). In conclusion, thermal management during the larval period can be a strategy to increase the proportion of males, but the increase in mortality due to the rise in temperature should be considered.(AU)

O presente estudo avaliou a influência da manipulação térmica durante a larvicultura de Betta splendens na sobrevivência e razão sexual, buscando aumento na proporção de machos. Larvas recém-eclodidas foram submetidas a diferentes regimes térmicos, denominados: T25, T28, T30 e T33 (25, 28, 30 e 33°C, respectivamente). Seguiu-se um delineamento inteiramente casualizado, com 4 tratamentos e 10 repetições. O tratamento termal foi mantido até os 15 DPE (dias pós-eclosão). No encerramento do regime termal e novamente aos 45 DPE foi contabilizada a mortalidade. No final do experimento foi contabilizado o número de machos e fêmeas obtidos nos diferentes tratamentos térmicos para análise da proporção sexual obtida. Houve efeito significativo da mortalidade em função da temperatura apenas aos 15 DPE (p <0,001) e os tratamentos T25, T28 e T30 apresentaram os menores valores para tal parâmetro. Para a razão sexual, foram obtidos até 65% de machos no tratamento T33 (p = 0,037). Conclui-se que a manipulação termal durante o período larval pode ser uma estratégia para o aumento da proporção de machos, considerando o aumento da mortalidade em função da elevação da temperatura.(AU)

Post-larval Colossoma macropomum (Characiformes, Serrasalmidae) show better performance in excavated than concrete tanks under different feeding strategies

As the global human population increases, the demand for food grows and, consequently, practices such as aquaculture have become more common. Colossoma macropomum (Cuvier, 1818) is a native Amazonian species, considered to be the second most cultivated fish in the country. We compared the development of post-larval C. macropomum of different ages, submitted to combinations of food management on a commercial production scale. Two experiments tested the delivery of i) 55% crude protein feeding, ii) natural feeding by fertilizing the water and iii) a combination of both during hatchery in concrete tanks (10 m 2) or excavated soil-bottom tanks (4502) subjected to distinct fertilization protocols and storage densities. The weight and length of the post-larvae grown in ponds were greater (p < 2.0x10-16) for the mixed treatment, except during the first week of larvae, in which values were similar (p & 8804; 1.76x10-14) to the fertilization treatment. Concrete tanks with fertilization management without feeding were similar to the mixed treatment (p & 8804; 1.38x10-7); however, during the first week of external larvae production, the growth performance under fertilization treatment was superior to the others. Food management in excavated tanks, when compared to the same management performed in concrete tanks, registered higher averages for the productive variables of C. macropomum cultivated at the density of 200 post-larvae m-2 in all evaluated food strategies. It was verified that post-larvae of C. macropomum did not develop well in the first weeks of life when receiving only formulated diets. The increase in natural food availability through fertilization positively influenced the performance of the species, which can remain without feeding until the second week of life.(AU)

The effect of fairy shrimp “branchoneta” (Dendrocephalus brasiliensis) as the initial diet of tambaqui postlarvae

The effect of fairy shrimp “branchoneta” as the first exogenous feed for tambaqui postlarvae was evaluated. A hundred and eighty larvae were distributed in 12 aquariums, containing 1.5L of water and the stocking density was 10 larvae per liter. The trials lasted for 20 days and postlarvae were submitted to three diets (T1: Commercial feed, T2: branchoneta, and T3: Commercial feed with branchoneta), with a completely randomized design with four replicates for each treatment. During the trials, the water quality parameters were kept within ideal conditions for the species. The tambaqui postlarvae submitted to T2 and T3 showed better survival rates respectively. Regarding the postlarval development, larvae fed with only branchoneta had a better final weight (3.48 mg), daily weight gain (0.14 mg day-1), and the best specific growth rate (8.62%). The results also showed that the tambaqui postlarvae fed with only commercial feed developed less efficiently due to lower rates of survival and growth. The present study indicates that the branchoneta promoted greater development and survival rates of the tambaqui postlarvae and therefore, it presents good potential as a live food for the species.(AU)

The effect of fairy shrimp “branchoneta” (Dendrocephalus brasiliensis) as the initial diet of tambaqui postlarvae

The effect of fairy shrimp “branchoneta” as the first exogenous feed for tambaqui postlarvae was evaluated. A hundred and eighty larvae were distributed in 12 aquariums, containing 1.5L of water and the stocking density was 10 larvae per liter. The trials lasted for 20 days and postlarvae were submitted to three diets (T1: Commercial feed, T2: branchoneta, and T3: Commercial feed with branchoneta), with a completely randomized design with four replicates for each treatment. During the trials, the water quality parameters were kept within ideal conditions for the species. The tambaqui postlarvae submitted to T2 and T3 showed better survival rates respectively. Regarding the postlarval development, larvae fed with only branchoneta had a better final weight (3.48 mg), daily weight gain (0.14 mg day-1), and the best specific growth rate (8.62%). The results also showed that the tambaqui postlarvae fed with only commercial feed developed less efficiently due to lower rates of survival and growth. The present study indicates that the branchoneta promoted greater development and survival rates of the tambaqui postlarvae and therefore, it presents good potential as a live food for the species.

Food acceptance in different larval stages of Macrobrachium carcinus / Aceitação de alimentos em diferentes estágios larvais de Macrobrachium carcinus

Food acceptance in different larval stages of Macrobrachium carcinus was evaluated by investigating the stage at which the ingestion of inert moist diet food begins and by the incidence of Artemia nauplii and inert moist diet in the digestive tract throughout development. Two experiments were carried out: in the first study, the acceptance of the inert diet was evaluated in 60 larvae of each stage (I to XII) fed ad libitum after two hours of fasting. The inert diet was 100% accepted at zoea stage V. In the second study, newly hatched larva was then kept in larval tanks and fed with Artemia nauplii and inert moist diet simultaneously. Fifteen minutes after feeding, 50 specimens of each larval stage were examined and evaluated for the ingestion of these foods. Larvae at stage I did not feed, while larvae at stage II consumed both live and inert food. From the stage of zoea IX, the exclusive consumption of Artemia nauplii was not verified. These data indicate that feeding M. carcinus in larviculture can be initiated at stage II with inert moist diet and Artemia nauplii, and an exclusive supply of inert moist diet from stage IX can be recommended.

A aceitação alimentar nos diferentes estágios larvais de Macrobrachium carcinus foram avaliadas a partir da investigação da fase em que começa a ingestão de uma dieta inerte úmida e a incidência de náuplios de Artemia e da dieta inerte úmida no trato digestório durante todo o desenvolvimento. Foram realizados dois experimentos: no primeiro, a aceitação da dieta inerte foi avaliada em 60 larvas de cada estágio (I a XII) alimentadas ad libitum após duas horas de jejum. A dieta inerte úmida foi 100% aceita na fase V de zoea. No segundo experimento, larvas recém-eclodidas foram mantidas em tanques larvais e alimentadas com náuplios de Artemia e dieta inerte úmida simultaneamente. Quinze minutos após a alimentação, 50 espécimes de cada estágio larval foram examinados e avaliados em relação à ingestão desses alimentos. Larvas no estágio I não se alimentaram, enquanto larvas no estágio II consumiram alimento vivo e inerte. A partir do estágio de zoea IX o consumo exclusivo de náuplios de Artemia não foi verificado. Esses dados indicam que a alimentação de M. carcinus na larvicultura pode ser iniciada no estágio II, com dieta úmida inerte e náuplios de Artemia, e pode ser recomendado o fornecimento exclusivo de dietas úmidas inertes a partir do estágio IX.

Food acceptance in different larval stages of Macrobrachium carcinus / Aceitação de alimentos em diferentes estágios larvais de Macrobrachium carcinus

Food acceptance in different larval stages of Macrobrachium carcinus was evaluated by investigating the stage at which the ingestion of inert moist diet food begins and by the incidence of Artemia nauplii and inert moist diet in the digestive tract throughout development. Two experiments were carried out: in the first study, the acceptance of the inert diet was evaluated in 60 larvae of each stage (I to XII) fed ad libitum after two hours of fasting. The inert diet was 100% accepted at zoea stage V. In the second study, newly hatched larva was then kept in larval tanks and fed with Artemia nauplii and inert moist diet simultaneously. Fifteen minutes after feeding, 50 specimens of each larval stage were examined and evaluated for the ingestion of these foods. Larvae at stage I did not feed, while larvae at stage II consumed both live and inert food. From the stage of zoea IX, the exclusive consumption of Artemia nauplii was not verified. These data indicate that feeding M. carcinus in larviculture can be initiated at stage II with inert moist diet and Artemia nauplii, and an exclusive supply of inert moist diet from stage IX can be recommended.(AU)

A aceitação alimentar nos diferentes estágios larvais de Macrobrachium carcinus foram avaliadas a partir da investigação da fase em que começa a ingestão de uma dieta inerte úmida e a incidência de náuplios de Artemia e da dieta inerte úmida no trato digestório durante todo o desenvolvimento. Foram realizados dois experimentos: no primeiro, a aceitação da dieta inerte foi avaliada em 60 larvas de cada estágio (I a XII) alimentadas ad libitum após duas horas de jejum. A dieta inerte úmida foi 100% aceita na fase V de zoea. No segundo experimento, larvas recém-eclodidas foram mantidas em tanques larvais e alimentadas com náuplios de Artemia e dieta inerte úmida simultaneamente. Quinze minutos após a alimentação, 50 espécimes de cada estágio larval foram examinados e avaliados em relação à ingestão desses alimentos. Larvas no estágio I não se alimentaram, enquanto larvas no estágio II consumiram alimento vivo e inerte. A partir do estágio de zoea IX o consumo exclusivo de náuplios de Artemia não foi verificado. Esses dados indicam que a alimentação de M. carcinus na larvicultura pode ser iniciada no estágio II, com dieta úmida inerte e náuplios de Artemia, e pode ser recomendado o fornecimento exclusivo de dietas úmidas inertes a partir do estágio IX.(AU)

Piscicultura brasileira e a influência da ordem odonata, uma revisão / Brazilian fish farming and the influence of the odonata order, a review / Piscicultura brasileña y la influencia del orden odonata, una revisión

A piscicultura brasileira está em expansão no Brasil, um setor que cresce a cada ano, porém na fase da larvicultura onde os peixes são inseridos em viveiros escavados, os mesmos em decorrência da sua vulnerabilidade e tamanho ficam susceptíveis à doenças e predadores. Dentre os predadores da piscicultura estão os insetos aquáticos, no qual os da ordem Odonata são considerados os principais. A ordem Odonata apesar de causar a predação na larvicultura de peixes é importante, pois desempenham papéis importantes no ambiente aquático e são considerados bioindicadores. Mesmo com essa importância, o piscicultor para resolver esses problemas, acaba por despejar defensivos agrícolas ou proporcionar a calagem intensa que pode trazer consequências graves tanto para os peixes como para a qualidade da água, diante disso seria necessário pensar em sustentabilidade na piscicultura com um manejo ou um controle natural desses predadores para que não haja impactos ambientais. Portanto, o objetivo desse trabalho foi abordar o histórico da piscicultura brasileira, os problemas enfrentados na larvicultura por predação de Odonata e oferecer alternativas sustentáveis de controle.(AU)

Brazilian fish farming is expanding in Brazil, presenting exceptional annual growth. However, during the larviculture phase, where fish is inserted in excavated ponds, due to their vulnerability and size, they become susceptible to diseases and predators. Aquatic insects feature among the predators in fish farming, with the Odonata order being the most prominent. Despite their predatory action during the larvae phase of fish, the Odonata order plays an important role in the aquatic environment and is considered as bioindicators. Despite its importance, to solve these problems, fish farmers end up using agrochemicals or providing intense liming, which can have serious consequences for both fish and water quality. Therefore, in face of this scenario, further studies on fish farming sustainability with management or control of those predators would be important in order to mitigate the environmental impacts. Thus, the objective of this paper was to address the history of Brazilian fish farming, the problems faced in larviculture due to predation by Odonata and to offer sustainable control alternatives.(AU)

La piscicultura brasileña se está expandiendo en Brasil, un sector que crece cada año, sin embargo, en la fase de larvicultura donde los peces se insertan en estanques excavados, por su vulnerabilidad y tamaño se quedan susceptibles a enfermedades y depredadores. Entre los depredadores de la piscicultura se encuentran los insectos acuáticos, los del orden Odonata son considerados los principales. El orden Odonata, a pesar de causar depredación en la larvicultura de peces es importante porque desempeñan papeles valiosos en el medio acuático y se consideran bioindicadores. Mismo con esa importancia, el piscicultor para solucionar esos problemas, acaba tirando plaguicidas o proporcionando un encalado intenso que puede traer graves consecuencias tanto para los peces como para la calidad del agua, considerando que sería necesario pensar en la sostenibilidad de la piscicultura con un manejo o control natural de esos depredadores para que no haya impactos ambientales. Por lo tanto, el objetivo de ese estudio ha sido abordar el histórico de la piscicultura brasileña, los problemas que enfrenta la larvicultura debido a la depredación de Odonata y ofrecer alternativas de control sostenibles.(AU)

Piscicultura brasileira e a influência da ordem odonata, uma revisão / Brazilian fish farming and the influence of the odonata order, a review / Piscicultura brasileña y la influencia del orden odonata, una revisión

A piscicultura brasileira está em expansão no Brasil, um setor que cresce a cada ano, porém na fase da larvicultura onde os peixes são inseridos em viveiros escavados, os mesmos em decorrência da sua vulnerabilidade e tamanho ficam susceptíveis à doenças e predadores. Dentre os predadores da piscicultura estão os insetos aquáticos, no qual os da ordem Odonata são considerados os principais. A ordem Odonata apesar de causar a predação na larvicultura de peixes é importante, pois desempenham papéis importantes no ambiente aquático e são considerados bioindicadores. Mesmo com essa importância, o piscicultor para resolver esses problemas, acaba por despejar defensivos agrícolas ou proporcionar a calagem intensa que pode trazer consequências graves tanto para os peixes como para a qualidade da água, diante disso seria necessário pensar em sustentabilidade na piscicultura com um manejo ou um controle natural desses predadores para que não haja impactos ambientais. Portanto, o objetivo desse trabalho foi abordar o histórico da piscicultura brasileira, os problemas enfrentados na larvicultura por predação de Odonata e oferecer alternativas sustentáveis de controle.(AU)

Brazilian fish farming is expanding in Brazil, presenting exceptional annual growth. However, during the larviculture phase, where fish is inserted in excavated ponds, due to their vulnerability and size, they become susceptible to diseases and predators. Aquatic insects feature among the predators in fish farming, with the Odonata order being the most prominent. Despite their predatory action during the larvae phase of fish, the Odonata order plays an important role in the aquatic environment and is considered as bioindicators. Despite its importance, to solve these problems, fish farmers end up using agrochemicals or providing intense liming, which can have serious consequences for both fish and water quality. Therefore, in face of this scenario, further studies on fish farming sustainability with management or control of those predators would be important in order to mitigate the environmental impacts. Thus, the objective of this paper was to address the history of Brazilian fish farming, the problems faced in larviculture due to predation by Odonata and to offer sustainable control alternatives.(AU)

La piscicultura brasileña se está expandiendo en Brasil, un sector que crece cada año, sin embargo, en la fase de larvicultura donde los peces se insertan en estanques excavados, por su vulnerabilidad y tamaño se quedan susceptibles a enfermedades y depredadores. Entre los depredadores de la piscicultura se encuentran los insectos acuáticos, los del orden Odonata son considerados los principales. El orden Odonata, a pesar de causar depredación en la larvicultura de peces es importante porque desempeñan papeles valiosos en el medio acuático y se consideran bioindicadores. Mismo con esa importancia, el piscicultor para solucionar esos problemas, acaba tirando plaguicidas o proporcionando un encalado intenso que puede traer graves consecuencias tanto para los peces como para la calidad del agua, considerando que sería necesario pensar en la sostenibilidad de la piscicultura con un manejo o control natural de esos depredadores para que no haya impactos ambientales. Por lo tanto, el objetivo de ese estudio ha sido abordar el histórico de la piscicultura brasileña, los problemas que enfrenta la larvicultura debido a la depredación de Odonata y ofrecer alternativas de control sostenibles.(AU)

Sodium butyrate and peppermint essential oil in jundiá diet: performance, histology, and challenge of Ichthyophthirius multifiliis / Butirato de sódio e óleo essencial de hortelã-pimenta na dieta de jundiá: desempenho, histologia e desafio ao Ichthyophthirius multifiliis

The aim of the present study was to evaluate the zootechnical performance, intestinal mucosa, and reaction to infestation by the parasite Ichthyophthirius multifiliis in jundiá Rhamdia quelen larvae supplemented with Mentha piperita essential oil or sodium butyrate in their diets. Five diets were used over 30 days: diet free of additive inclusion, 0% (control); inclusion of 1% or 2% of M. piperita essential oil: EO1% and EO2%, respectively; and inclusion of 0.25% or 0.50% of sodium butyrate: SB0.25% and SB0.50%, respectively. The different diets were not able to inhibit I. multifiliis infestation. Supplementation with SB0.50% in their diets presented better performance in all zootechnical parameters analyzed, including a 54% increase in final weight and 70% in survival, and increased (P 0.05) both the villi width and the amount of goblet cells present in the intestinal mucosa by approximately 50%. In view of these results, dietary supplementation of R. quelen larvae with 0.50% sodium butyrate for 30 days is recommended.(AU)

O objetivo do presente estudo foi avaliar o desempenho zootécnico, a mucosa intestinal, a resistência ao estresse e a reação à infestação pelo parasita Ichthyophthirius multifiliis em larvas de jundiá Rhamdia quelen suplementadas com óleo essencial de Mentha piperita ou butirato de sódio em suas dietas. Foram utilizadas cinco dietas por 30 dias: dieta livre de inclusão de aditivos, 0% (controle); inclusão de 1% ou 2% de óleo essencial de M. piperita, EO1% e EO2%, respectivamente; e inclusão de 0,25% ou 0,50% de butirato de sódio, SB0.25% e SB0.50%, respectivamente. As diferentes dietas não foram capazes de inibir a infestação por I. multifiliis. A suplementação com SB0.50% em suas dietas apresentou melhor desempenho em todos os parâmetros zootécnicos analisados, incluindo um aumento do peso final em 54% e a sobrevivência em 70%, e aumentou (P 0,05) a largura das vilosidades e a quantidade de células caliciformes presentes na mucosa intestinal em aproximadamente 50%. Em vista desses resultados, recomenda-se a suplementação dietética de larvas de R. quelen com butirato de sódio a 0,50% por 30 dias.(AU)

Maturation, spawning and larviculture of the mullet Mugil liza under laboratory conditions / Maturação, desova e larvicultura da tainha Mugil liza em laboratório

The technical feasibility for the sustainable production of a species depends mainly on the control of reproduction in captivity and the availability of juveniles. Studies were performed with the mullet Mugil liza in the 1980s, however this species was never produced commercially. With the development of aquaculture, the increasing demand for animal protein and the commercial value of the mullet roe, it was necessary to rear this species in the laboratory to produce juveniles in pilot scale. The broodstock, 4 females and 10 males, were kept in an indoor 12 m³ tank. Hormonal inductions were performed with the hormones pituitary extract of carp (PEC) and luteinizing hormone-releasing hormone analog (LHRHa); spawnings occurred between 54-57 h after the hormonal induction. Embryonated eggs of mullets were pelagic and translucent, with an average diameter of 846.29 ± 14.34 µm. The larvae hatched approximately 48 h after spawning with 2.95 ± 0.12 mm. The survival in the larviculture was estimated at 18.75%. Therefore, this study presents the technical methods for the capture, transport, acclimatization, maturation, induced spawning and hatchery of the mullet M. liza in the laboratory.(AU)

A viabilidade técnica para a produção sustentável de uma espécie depende principalmente do controle da reprodução em cativeiro e da disponibilidade de juvenis. Estudos foram realizados com a tainha Mugil liza nos anos 80, entretanto, essa espécie não chegou a ser produzida comercialmente. Com o desenvolvimento da aquicultura, com a crescente demanda por proteína animal, além do valor comercial agregado nas gônadas dessa espécie, surgiu à necessidade de tentar produzi-la em laboratório, desta vez com o objetivo de produzir juvenis em escala-piloto. Os reprodutores, 4 fêmeas e 10 machos, foram mantidos em tanque de 12 m³. As induções hormonais foram realizadas com os hormônios extrato bruto de hipófise de carpa (EBHC) e um análogo do hormônio liberador do hormônio luteinizante (LHRHa); as desovas ocorreram 54-57 h depois da indução hormonal. Os ovos embrionados das tainhas são pelágicos e translúcidos, com um diâmetro médio de 846.29 ± 14.34 µm. As larvas eclodiram aproximadamente 48h após a desova com 2.95 ± 0.12 mm. A sobrevivência desde a estocagem dos ovos até a despesca dos juvenis foi estimada em 18,75%. Sendo assim, este estudo apresenta os métodos técnicos para a captura, transporte, aclimatação, maturação, desova induzida e larvicultura da tainha M. liza em laboratório.(AU)

Maturation, spawning and larviculture of the mullet Mugil liza under laboratory conditions / Maturação, desova e larvicultura da tainha Mugil liza em laboratório

The technical feasibility for the sustainable production of a species depends mainly on the control of reproduction in captivity and the availability of juveniles. Studies were performed with the mullet Mugil liza in the 1980s, however this species was never produced commercially. With the development of aquaculture, the increasing demand for animal protein and the commercial value of the mullet roe, it was necessary to rear this species in the laboratory to produce juveniles in pilot scale. The broodstock, 4 females and 10 males, were kept in an indoor 12 m³ tank. Hormonal inductions were performed with the hormones pituitary extract of carp (PEC) and luteinizing hormone-releasing hormone analog (LHRHa); spawnings occurred between 54-57 h after the hormonal induction. Embryonated eggs of mullets were pelagic and translucent, with an average diameter of 846.29 ± 14.34 µm. The larvae hatched approximately 48 h after spawning with 2.95 ± 0.12 mm. The survival in the larviculture was estimated at 18.75%. Therefore, this study presents the technical methods for the capture, transport, acclimatization, maturation, induced spawning and hatchery of the mullet M. liza in the laboratory.

A viabilidade técnica para a produção sustentável de uma espécie depende principalmente do controle da reprodução em cativeiro e da disponibilidade de juvenis. Estudos foram realizados com a tainha Mugil liza nos anos 80, entretanto, essa espécie não chegou a ser produzida comercialmente. Com o desenvolvimento da aquicultura, com a crescente demanda por proteína animal, além do valor comercial agregado nas gônadas dessa espécie, surgiu à necessidade de tentar produzi-la em laboratório, desta vez com o objetivo de produzir juvenis em escala-piloto. Os reprodutores, 4 fêmeas e 10 machos, foram mantidos em tanque de 12 m³. As induções hormonais foram realizadas com os hormônios extrato bruto de hipófise de carpa (EBHC) e um análogo do hormônio liberador do hormônio luteinizante (LHRHa); as desovas ocorreram 54-57 h depois da indução hormonal. Os ovos embrionados das tainhas são pelágicos e translúcidos, com um diâmetro médio de 846.29 ± 14.34 µm. As larvas eclodiram aproximadamente 48h após a desova com 2.95 ± 0.12 mm. A sobrevivência desde a estocagem dos ovos até a despesca dos juvenis foi estimada em 18,75%. Sendo assim, este estudo apresenta os métodos técnicos para a captura, transporte, aclimatação, maturação, desova induzida e larvicultura da tainha M. liza em laboratório.