Feeding rate and frequency on juvenile pompano growth

O objetivo deste trabalho foi avaliar a taxa e a frequência alimentar ideal para juvenis de pampo (Trachinotus marginatus). Foram conduzidos dois experimentos, em delineamento inteiramente casualizado, com três repetições cada um. No experimento I, 25 peixes (4,8±0,6 g e 6,48±0,01 cm) foram estocados em 15 tanques (50 L) durante 21 dias e alimentados com 4, 8, 12, 16 e 20% da biomassa total por dia. No experimento II, 20 peixes (4,1±0,1 g e 6,6±0,1 cm) foram estocados em 15 tanques (40 L) durante 28 dias e alimentados 2, 6, 8 e 10 vezes por dia. As taxas e as frequências alimentares testadas não influenciaram a sobrevivência. O peso e o comprimento finais no experimento I foram significativamente menores nos peixes alimentados com 4% da biomassa total por dia, enquanto, no experimento II, somente o peso foi significativamente menor nos peixes alimentados 2 e 6 vezes por dia. Ao final dos dois experimentos, a conversão alimentar aparente apresentou diferença significativa, com pior valor observado nos peixes alimentados com 20% da biomassa total por dia, no experimento I, e 2 vezes por dia no experimento II. Juvenis de pampo apresentam melhor desempenho de crescimento quando alimentados com 8% da biomassa total por dia e oito vezes por dia.The objective of this work was to evaluate the ideal feeding rate and frequency for juvenile pompano (Trachinotus marginatus). Two experiments were carried out in a completely randomized design, with three replicates each. In experiment I, 25 fish (4.8±0.6 g and 6.48±0.01 cm) were stocked in 15 tanks (50 L) during 21 days and fed 4, 8, 12, 16, and 20% body weight per day. In experiment II, 20 fish (4.1±0.1 g and 6.6±0.1 cm) were stocked in 15 tanks (40 L) during 28 days and fed 2, 6, 8, and 10 times a day. The tested feeding rates and frequencies did not influence survival. Final weight and length in experiment I were significantly lower in fish fed 4% body weight per day, whereas in experiment II only weight was significantly lower in fish fed 2 and 6 times a day. At the end of both experiments, apparent feed conversion showed significant difference, with the worst value observed for fish fed 20% body weight per day in experiment I and 2 times a day in experiment II. Juvenile pompano show better growth performance when fed 8% body weight per day and 8 times a day

Convalescent plasma for COVID-19 in hospitalised patients : an open-label, randomised clinical trial

Background: The effects of convalescent plasma (CP) therapy in hospitalised patients with coronavirus disease 2019 (COVID-19) remain uncertain. This study investigates the effect of CP on clinical improvement in these patients. Methods: This is an investigator-initiated, randomised, parallel arm, open-label, superiority clinical trial. Patients were randomly (1:1) assigned to two infusions of CP plus standard of care (SOC) or SOC alone. The primary outcome was the proportion of patients with clinical improvement 28 days after enrolment. Results: A total of 160 (80 in each arm) patients (66.3% critically ill, 33.7% severely ill) completed the trial. The median (interquartile range (IQR)) age was 60.5 (48–68) years; 58.1% were male and the median (IQR) time from symptom onset to randomisation was 10 (8–12) days. Neutralising antibody titres >1:80 were present in 133 (83.1%) patients at baseline. The proportion of patients with clinical improvement on day 28 was 61.3% in the CP+SOC group and 65.0% in the SOC group (difference −3.7%, 95% CI −18.8–11.3%). The results were similar in the severe and critically ill subgroups. There was no significant difference between CP+SOC and SOC groups in pre-specified secondary outcomes, including 28-day mortality, days alive and free of respiratory support and duration of invasive ventilatory support. Inflammatory and other laboratory marker values on days 3, 7 and 14 were similar between groups. Conclusions: CP+SOC did not result in a higher proportion of clinical improvement on day 28 in hospitalised patients with COVID-19 compared to SOC alone

Efeito da taxa arraçoamento e da freqüência alimentar no crescimento de juvenis do pampo Trachinotus marginatus

Dissertação(mestrado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Aqüicultura, Instituto de Oceanografia, 2008.A família Carangidae engloba uma série de peixes economicamente importantes, abundantes em águas tropicais e sub-tropicais. O pampo Trachinotus marginatus apresenta fácil adaptação a sistemas intensivos de criação, comprovado pela rápida aceitação de dieta artificiais. Entretanto, para determinar a viabilidade do cultivo de uma espécie é necessário o conhecimento dos fatores limitantes para sua produção. A taxa de arraçoamento e a freqüência alimentar apropriada são importantes para o correto manejo alimentar de uma espécie cultivada. O conhecimento da “Specific dynamic action” (SDA) também é importante e pode auxiliar na determinação da capacidade suporte do sistema de produção. O objetivo deste trabalho foi estabelecer a taxa ótima de arraçoamento, a freqüência alimentar adequada e estudar a taxa de consumo de oxigênio pós-prandial para juvenis do pampo. Os experimentos foram realizados com juvenis (4,8±0,6g) coletados na natureza e aclimatados ao laboratório. Foram testadas diferentes taxas de arraçoamento (4, 8, 12, 16 e 20% da biomassa total por dia) e freqüência alimentar (2, 4, 6, 8 e 10 vezes por dia). O consumo de oxigênio foi avaliado com peixes alimentados com 12% da biomassa por dia. É sugerido o uso de uma taxa de arraçoamento de 8% da biomassa por dia e a freqüência alimentar de 6 a 8x/dia para juvenis de pampo, de modo a otimizar o crescimento e a taxa de conversão alimentar aparente. Foi observado um pico de consumo de oxigênio aos 30 min após a alimentação e decorridos 150 min da alimentação, o consumo de oxigênio retornou ao nível basal.Carangidae fish are economically important fish, abundant in tropical and subtropical environments. Pompano Trachinotus marginatus easily adapts to captivity, since wild caught fish accept dry diets soon after being captured. However, in order to determine the viability of a new species for aquaculture, it is important to know the limiting factors for its production. Daily ration and feeding frequency are important parameters to control regarding feeding management for juvenile rearing. Specific dynamic action is also important and can help to determine carrying capacity of a given rearing system. The objective of this work was to determine optimum daily ration and feeding frequency, and to study post-pandrial oxygen consumption. Wild caught juvenile pompano (4.8±0.6g) captured in the surf zone at Cassino beach (Brazil). Two independent feeding trials were carried in laboratory. In trial I pompano were fed 4, 8, 12, 16 and 20% total biomass daily (% B.D-1). In trial II, juveniles were fed 2, 4, 6, 8 and 10 times per day. The postprandial metabolic changes were measured with juvenile pompano fed 12%B.D-1. The best feeding ration was 8% B.D-1, while optimum feeding frequency was between 6 and 8 meals per day to maximize growth and feed conversion rate. Postprandial increase in oxygen consumption was observed 30 min after feeding and after 150 min it decreased to the standard metabolic rate

Effects of salinity on growth of juvenile mullet Mugil platanus

Assuming the energetic cost of osmoregulation is minimized in an isosmotic medium, the energy spared could support a higher growth rate of fish. The isosmotic point of juvenile mullet Mugil platanus was estimated at 414 mOsmol/Kg H2O, which corresponds to salinity 12‰.The aim of this study was to investigate the effect of salinity on the performance of juvenile mullet reared at different salinities. Four hundred and eighty fish (0.48±0.01g and 3.27±0.01cm) were randomly distributed into 16 tanks (50L). These tanks were connected to four recirculating aquaculture systems (RAS) equipped with UV sterilization, mechanical and biological filtration and temperature controllers. Each RAS was maintained at salinities 0, 6, 12, and 24, equivalent to 0, 50, 100 and 200% of the isosmotic point of M. platanus. During the experimental period (40 days), fish were maintained at 28.2 ± 0.1°C and oxygen saturation was always above 90%. Fish were fed 4 times per day on NRD INVE (50% protein) until apparent satiation. Results were analyzed by analysis of variance (One-Way) followed by Test of Tukey. All analyses were performed with significance level of p<0.05 and were conducted using the software Statistic 6.0. Salinity did not influence survival of juvenile mullet (p>0.05), nor influenced feed efficiency. However, final weight and specific growth rate were significantly affected at different salinities (p<0.05). Overall survival was above 90% and feed efficiency was y. Fish reared at salinities 12 and 24 grew faster than those reared at lower salinities (Figure 1 and 2) Results indicated that salinity plays an important role in juvenile mullet growth and that final weight and SGR were maximized when they were reared at salinity equivalent to, or higher, than the isosmotic point

Acclimation of juvenile Mugil liza Valenciennes, 1836 (Mugiliformes: Mugilidae) to different environmental salinities

Survival and physiological parameters associated with metabolism and osmoregulation were evaluated in juveniles of the Lebranche mullet Mugil liza acclimated to different water salinities (5, 10, 20, 30, and 40‰) for 15 days. Room temperature (25ºC) and photoperiod (12L:12D) were fixed. Fish were fed twice-a-day with commercial diet (28% crude protein) until satiation. After acclimation, whole body oxygen consumption was measured and fish were euthanized and sampled for blood, gills, and liver. Whole body oxygen consumption and plasma osmolality did not change in the range of salinities tested. The isosmotic point was estimated as 412.7 mOsmol kg-1 (13.5‰). Gill Na+,K+-ATPase activity tended to be lower at 20 and 30‰, while liver glycogen content was significantly higher at 20‰ than at 5 and 40‰. These results indicate that juvenile M. liza is able to acclimate for a short-period of time (15 days) to a wide range of salinities (5-40‰). This condition is achieved through adjustments in gill Na+,K+-ATPase activity and carbohydrate metabolism to regulate plasma osmolality and aerobic/energy metabolism. Therefore, our findings support the idea of catching juveniles M. liza in sea water and rear them in estuarine and marine waters

Acclimation of juvenile mugil iiza valenciennes, 1836 (mugiliformes: mugilidae) to different environmental salinities

Survival and physiological parameters associated with metabolism and osmoregulation were evaluated in juveniles of the Lebranche mullet Mugil liza acclimated to different water salinities (5, 10, 20, 30, and 40‰) for 15 days. Room temperature (25°C) and photoperiod (12L:12D) were fixed. Fish were fed twice-a-day with commercial diet (28% crude protein) until satiation. After acclimation, whole body oxygen consumption was measured and fish were euthanized and sampled for blood, gills, and liver. Whole body oxygen consumption and plasma osmolality did not change in the range of salinities tested. The isosmotic point was estimated as 412.7 mOsmol kg-1 (13.5‰). Gill Na+ ,K+-ATPase activity tended to be lower at 20 and 30‰, while liver glycogen content was significantly higher at 20‰ than at 5 and 40‰. These results indicate that juvenile M. liza is able to acclimate for a short-period of time (15 days) to a wide range of salinities (5-40‰). This condition is achieved through adjustments in gill Na+ ,K+-ATPase activity and carbohydrate metabolism to regulate plasma osmolality and aerobic/energy metabolism. Therefore, our findings support the idea of catching juveniles M. liza in sea water and rear them in estuarine and marine waters.A sobrevivência e parâmetros fisiológicos associados ao metabolismo e a osmorregulação foram avaliados em juvenis da tainha Mugil liza aclimatada à diferentes salinidades (5, 10, 20, 30 e 40‰) por 15 dias. Foram fixadas a temperatura (25°C) e o fotoperíodo (12L:12D) da sala onde os experimentos foram realizados. Os peixes foram alimentados duas vezes ao dia com ração comercial (28% de proteína bruta) até a saciedade. Após aclimatação, foi medido o consumo corporal de oxigênio e os peixes foram eutanasiados e foram coletadas amostras de sangue, brânquias e fígado. O consumo corporal de oxigênio e a osmolalidade plasmática não variaram na faixa de salinidade testada. O ponto isosmótico foi estimado em 412,7 mOsmol kg-1 (13,5‰). A atividade da Na+ ,K+-ATPase branquial tendeu a ser menor em 20 e 30‰, enquanto o conteúdo de glicogênio hepático foi significativamente maior em 20‰ do que em 5 e 40‰. Estes resultados indicam que o juvenil de M. liza é capaz de se aclimatar a uma ampla faixa de salinidade (5-40‰) por um curto período de tempo (15 dias). Esta condição é atingida através de ajustes na atividade da Na+ ,K+-ATPase branquial e no metabolismo de carboidratos para regular a osmolalidade plasmática e o metabolismo aeróbico/energético. Portanto, nossos achados suportam a ideia de que é possível capturar juvenis da tainha M. liza em água do mar e cultivá-los em águas estuarinas e marinhas

Consumo de oxigênio pós-prandial de juvenis do pampo Trachinotus marginatus Postprandial oxygen consumption of juvenile pompano Trachinotus marginatus

Para determinar a viabilidade do cultivo de uma espécie, é importante o conhecimento dos fatores limitantes para sua produção. Conhecer a taxa de consumo de oxigênio pós-prandial pode auxiliar na determinação da freqüência alimentar ideal para as espécies cultivadas. O objetivo deste trabalho foi estudar a taxa de consumo de oxigênio pós-prandial para juvenis do pampo Trachinotus marginatus. A avaliação do consumo de oxigênio foi feita a 24°C e 33&#137;, com pampos (9,64±0,2g) alimentados com 12% da biomassa por dia com dieta NRD INVE (59% proteína). Foi observado um pico de consumo de oxigênio 30min após a alimentação (1,06mgO2 g-1 h-1) e seu retorno ao nível de jejum (0,79mgO2 g-1 h-1) depois de decorridos mais 120min. A alimentação de juvenis de pampo pode ser realizada com uma freqüência de aproximadamente oito vezes por dia, pois a cada 2,5h a taxa de consumo de oxigênio já não mostra a elevação característica da fase pós-prandial, sugerindo que os processos de digestão e assimilação dos nutrientes estejam finalizados.<br>In order to determine the viability of new species for aquaculture, it is important to know the limiting factors for its production. The knowledge about postprandial oxygen consumption of fish is useful to estimate the time for returning to appetite and allows to estimate the proper feeding frequency. The objective of this research was to study the postprandial oxygen consumption of juvenile pompano Trachinotus marginatus. Oxygen consumption rate was determined at 24°C and 33&#137; and fish (9.64±0.2g) were fed daily with 12% total of biomass NRD INVE diet (59% protein). Postprandial increase in oxygen consumption was observed 30min after feeding (1.06mgO2 g-1 h-1), and it returned to the routine metabolic rate (0.79mgO2 g-1 h-1) within the next 120min. According to these results, it seems appropriated to feed juvenile pompano 8 times per day, because every 2.5h the oxygen consumption rate declines to the unfed level, suggesting that the process of digestion and assimilation have already finished

Dietary salt supplementation for juvenile mullet Mugil platanus reared in freshwater

Dietary salt supplementation for seawater/euryhaline fish reared in low salinities and/or freshwater might spare energy expenditure for osmoregulation allowing more energy for growth. Growth of mullet Mugil platanus is hampered in hypoosmotic environments, thus the objective of this study was to evaluated the effect of dietary salt supplementation on their performance when reared in freshwater. Two hundred and forty fish (4.50 ± 0.07g e 7.41 ± 0.03cm) were randomly distributed into 16 tanks (50L). These tanks were connected to a recirculating aquaculture system (RAS) equipped with UV sterilization, mechanical and biological filtration and temperature controller. A commercial diet (32%CP and 1.5% NaCl) was grinded to powder, supplemental salt was added, and cellulose was used to compensate for the extra salt. Fish were fed 3 times per day on diets supplemented with 0, 3, 6, and 9% NaCl. During the experiment, fish were maintained at temperature of 27 ± 0.1°C, oxygen saturation above 89%, 78.56 ± 1.09, 7.92 ± 0.02 and photoperiod 14C:10E. Fish were fed three times per day until apparent satiation. Biometry was made every 15 days. The data (average ± SE) were analyzed by analysis of variance (One-Way) (ANOVA) followed by Test of Tukey. All analyses were performed with significance level of p<0.05 and were conducted using the software statistic 6.0. Dietary salt supplementation did not affect survival of juvenile mullet, survival was above 90% in all tanks. Feed efficiency was not influenced by the experimental diets either, it averaged 0.31 ± 0.01 (p>0.05). However, final weight of juvenile mullet fed NaCl-enriched diets (6 and 9%) was significantly smaller than fish fed control or NaCl-enriched (3%) diets (p<0.05) (Figure 1). Considering the specific growth rate, juvenile mullet fed NaCl-enriched diet (9%) showed the poorest performance when compared to fish fed any other diet (Figure 2). Results indicated that diets supplemented with NaCl are not beneficial to juvenile mullet. Furthermore, excess salt (6% and 9% NaCl) are harmfull and compromise their growt

Consumo de oxigênio pós-prandial de juvenis do pampo Trachinotus marginatus

Para determinar a viabilidade do cultivo de uma espécie, é importante o conhecimento dos fatores limitantes para sua produção. Conhecer a taxa de consumo de oxigênio pós-prandial pode auxiliar na determinação da freqüência alimentar ideal para as espécies cultivadas. O objetivo deste trabalho foi estudar a taxa de consumo de oxigênio pós-prandial para juvenis do pampo Trachinotus marginatus. A avaliação do consumo de oxigênio foi feita a 24°C e 33‰, com pampos(9,64±0,2g) alimentados com 12% da biomassa por dia com dieta NRD INVE (59% proteína). Foi observado um pico de consumo de oxigênio 30min após a alimentação (1,06mgO2 g-1 h-1) e seu retorno ao nível de jejum (0,79mgO2 g-1 h-1) depois de decorridos mais 120min. A alimentação de juvenis de pampo pode ser realizada com uma freqüência de aproximadamente oito vezes por dia, pois a cada 2,5h a taxa de consumo de oxigênio já não mostra a elevação característica da fase pósprandial, sugerindo que os processos de digestão e assimilação dos nutrientes estejam finalizados.In order to determine the viability of new species for aquaculture, it is important to know the limiting factors for its production. The knowledge about postprandial oxygen consumption of fish is useful to estimate the time for returning to appetite and allows to estimate the proper feeding frequency. The objective of this research was to study the postprandial oxygen consumption of juvenile pompano Trachinotus marginatus. Oxygen consumption rate was determined at 24°C and 33‰ and fish (9.64±0.2g) were fed daily with 12% total of biomass NRD INVE diet (59% protein). Postprandial increase in oxygen consumption was observed 30min after feeding (1.06mgO2 g-1 h-1), and it returned to the routine metabolic rate (0.79mgO2 g-1 h-1) within the next 120min. According to these results, it seems appropriated to feed juvenile pompano 8 times per day, because every 2.5h the oxygen consumption rate declines to the unfed level, suggesting that the process of digestion and assimilation have already finished