Ajustes no metabolismo de proteínas e lipídios no jundiá (Rhamdia quelen) durante diferentes períodos de jejum e realimentação

The fish may experience periods of food deprivation or starvation which produce metabolic changes. In this study, adult Rhamdia quelen males were subjected to fasting periods of 1, 7, 14, and 21 days and of refeeding 2, 4, 6, and 12 days. The results demonstrated that liver protein was depleted after 1 day of fasting, but recovered after 6 days of refeeding. After 14 days of fasting, mobilization in the lipids of the muscular tissue took place, and these reserves began to re-establish themselves after 4 days of refeeding. Plasmatic triglycerides increased after 1 day of fasting, and decreased following 2 days of refeeding. The glycerol in the plasma oscillated constantly during the different periods of fasting and refeeding. Changes in the metabolism of both protein and lipids during these periods can be considered as survival strategies used by R. quelen. The difference in the metabolic profile of the tissues, the influence of the period of fasting, and the type of reserves mobilized were all in evidence.Os peixes podem sofrer períodos de privação de alimentos ou de fome, que produzem mudanças metabólicas. Neste estudo, jundiás machos adultos foram submetidos a jejum períodos de 1, 7, 14 e 21 dias e realimentação 2, 4, 6, e 12 dias. Os resultados demonstraram que a proteína do fígado foi esgotada depois de um dia de jejum, mas restabeleceu após 6 dias de realimentação. Após 14 dias de jejum, ocorreu a mobilização dos lípidos no tecido muscular sendo que estas reservas começaram a re-estabelecer-se após 4 dias de realimentação. Os triglicérides plasmáticos aumentam após um dia de jejum, e diminuiram após 2 dias de realimentação. O glicerol no plasma oscilou constantemente durante os diferentes períodos de jejum e realimentação. As alterações no metabolismo de proteína e lipídios durante estes períodos podem ser consideradas uma estratégias de sobrevivência utilizada pelo Rhamdia quelen. Sendo que a diferença no perfil metabólico tecidual bem como a influência do período de jejum e o tipo de reserva a ser mobilizada foram observadas neste estudo

Increase of oil level in isoenergetic diets of exercising horses

O efeito da inclusão de óleo de soja na dieta foi avaliado em 4 cavalos machos castrados, mestiços Quarto de Milha, com idade aproximada de 42 meses e peso médio inicial de 382kg. Os cavalos foram submetidos a exercício de intensidade e duração média e receberam a dieta controle (sem óleo de soja) e a dieta com óleo de soja (4,7% de óleo) duas vezes ao dia, por 3 períodos de 21 dias, num delineamento do tipo Reversão Simples. A ração foi fornecida de modo a proporcionar uma ingestão diária isoprotéica e isoenergética para os dois tratamentos. Foram avaliados os seguintes parâmetros: freqüência cardíaca (FC), freqüência respiratória (FR) e a concentração de glicogênio muscular, antes do exercício e 20 minutos após o término do exercício, e os níveis plasmáticos de glicose e de lactato, antes do exercício e aos 10, 20, 30 e 50 minutos após o exercício. O aumento do nível de óleo na dieta não influenciou significativamente (P>0,05) a FC, a FR, os níveis de glicose e de lactato, antes e após o exercício. A concentração de glicogênio muscular foi maior (P0.05) the HR, the RR, the glucose and lactate plasma levels, before and after the exercise. The muscle glycogen concentration was higher (P<0.025), before exercise, for the horses that received the diet containing soybean oil. The increase of glycogen concentration in horses conditioned to consume a diet containing soybean oil may imply in a greater amount of energy to the muscle activity during exercising

Efeito de diferentes dietas sobre os níveis de ATP teciduais do caranguejo Chasmagnathus granulata submetidos a anoxia e recuperação

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Efeito da anoxia e da fase de recuperação da anoxia sobre a atividade da hexoquinase no caranguejo Chasmagnathus granulata mantidos com uma dieta rica em carboidratos (RC) ou proteína (RP)

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Efeito da anoxia e da fase de recuperação da anoxia sobre a atividade da hexoquinase no caranguejo Chasmagnathus granulata mantidos com uma dieta rica em carboidratos (RC) ou proteína (RP)

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Efeito da anoxia e da fase de recuperação da anoxia sobre a via glicolítica em Chasmagnathus granulata mantidos com uma dieta rica em carboidratos ou proteínas

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Feeding regimen modulates zebrafish behavior

Here we show that the feeding regimen modulates zebrafish (Danio rerio) behavior. With regard to the time elapsed between feeding and behavioral evaluation, fish fed 3 h before behavioral evaluation in the novel tank test (NTT) showed decreased activity and a trend toward an anxiolytic reaction (increased use of the upper section of the aquarium) in comparison to fish fed 0.5, 6, 12, 24 or 48 h before testing, although differences were not statistically significant for all comparisons. Activity and use of the upper section of the aquarium did not differ significantly among the other treatments. Regarding feeding frequency, fish fed once a day showed higher anxiety-like behavior (decreased use of the upper section of the aquarium) in comparison to fish fed twice a day, but feeding four or six times per day or only every second day did not result in differences from feeding twice a day. Feeding frequency had no effect on activity level. Metabolically, fish fed once a day presented decreased levels of glucose and glycogen and increased lactate when compared to the regular feeding (fish fed twice a day), suggesting that feeding regimen may modulate carbohydrate metabolism. Mechanistically, we suggest that the metabolic changes caused by the feeding regimen may induce behavioral changes. Our results suggest that the high variability of the results among different laboratories might be related to different feeding protocols. Therefore, if issues pertaining to the feeding regimen are not considered during experiments with zebrafish, erroneous interpretations of datasets may occur

Feeding regimen modulates zebrafish behavior

Here we show that the feeding regimen modulates zebrafish (Danio rerio) behavior. With regard to the time elapsed between feeding and behavioral evaluation, fish fed 3 h before behavioral evaluation in the novel tank test (NTT) showed decreased activity and a trend toward an anxiolytic reaction (increased use of the upper section of the aquarium) in comparison to fish fed 0.5, 6, 12, 24 or 48 h before testing, although differences were not statistically significant for all comparisons. Activity and use of the upper section of the aquarium did not differ significantly among the other treatments. Regarding feeding frequency, fish fed once a day showed higher anxiety-like behavior (decreased use of the upper section of the aquarium) in comparison to fish fed twice a day, but feeding four or six times per day or only every second day did not result in differences from feeding twice a day. Feeding frequency had no effect on activity level. Metabolically, fish fed once a day presented decreased levels of glucose and glycogen and increased lactate when compared to the regular feeding (fish fed twice a day), suggesting that feeding regimen may modulate carbohydrate metabolism. Mechanistically, we suggest that the metabolic changes caused by the feeding regimen may induce behavioral changes. Our results suggest that the high variability of the results among different laboratories might be related to different feeding protocols. Therefore, if issues pertaining to the feeding regimen are not considered during experiments with zebrafish, erroneous interpretations of datasets may occur