Efeitos da restrição alimentar e realimentação no crescimento, metabolismo, imunidade e no sistema antioxidante/estresse oxidativo de Piaractus mesopotamicus
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Data
2023-02-28
Autores
Sorrente, Thaís Lucato
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A aquicultura vem crescendo e a intensificação da produção traz consequências 3 negativas para os peixes e o meio ambiente. Nestes sistemas, a alimentação é 4 oferecida com alta frequência, diferente do que ocorre no ambiente natural, o que 5 torna possível o uso de ciclos de restrição do alimento e realimentação. Durante 6 períodos de jejum, os peixes mobilizam reservas energéticas e na realimentação 7 ativam mecanismos compensatórios para reposição destas reservas, o que altera a 8 dinâmica da produção de energia, quando dois sistemas podem ser afetados: o 9 sistema imune, de alto custo energético, e o sistema antioxidant, que é ativado durante 10 a ativação da respiração celular para combater os radicais livres formados. 11 Considerando o exposto, esse estudo avaliou a dinâmica metabólica, respostas 12 imunes inatas e do sistema antioxidante, durante a restrição alimentar e a 13 realimentação do pacu (Piaractus mesopotamicus). Para isso, os peixes foram 14 submetidos a ciclos de 3 dias de restrição e dois dias de realimentação por 30 dias ou 15 a 21 dias de restrição seguidos de 9 dias de realimentação e, ao final, inoculados com 16 lipopolissacarídeo (LPS). Os resultados mostraram que a restrição alimentar modulou 17 as reservas energéticas durante os 21 dias de restrição alimentar, e após 9 dias de 18 realimentação promoveu o crescimento compensatório e a recuperação das reservas 19 energéticas. O sistema imune (atividade respiratória dos leucócitos - ARL e lisozima 20 sérica) não foi afetado pela restrição alimentar, mas a realimentação ativou a ARL e 21 reduziu a concentração de lisozima. Em peixes privados de alimento, o sistema 22 antioxidante demonstrou prejuízos na capacidade de resposta. Embora houvesse 23 ativação de enzimas antioxidantes, a alta mobilização de energia durante o jejum 24 provocou estresse oxidativo.
Aquaculture is growing the intensification of production has negative consequences for fish and the environment. In these systems, feed is offered at a high frequency, unlike in the natural environment, which makes it possible to use feed restriction and refeeding cycles. During periods of fasting, fish mobilize energy reserves, and during re-feeding they activate compensatory mechanisms to replenish these reserves. Thus, metabolic changes alter the dynamics of energy production, and two systems may be affected: the immune system and the antioxidant system, which responds to the production of free radicals during the activation of cellular respiration. Considering the above, this study evaluated the metabolic dynamics, innate immune and antioxidant system responses, during feed restriction and re-feeding of pacu (Piaractus mesopotamicus). The fish were subjected to cycles of 3 days of restriction and 2 days of refeeding for 30 days or to 21 days of restriction followed by 9 days of refeeding and, at the end, inoculated with lipopolysaccharide (LPS). The results of this study showed that dietary restriction modulated energy reserves during the 21 days of dietary restriction, and after 9 days of refeeding promoted compensatory growth and recovery of energy reserves. The immune system (leukocyte respiratory activity and lysozyme) was not affected by dietary restriction, but refeeding activated ARL and reduced serum lysozyme concentration. In food-deprived fish, the antioxidant system showed impaired responsiveness. Although there was activation of antioxidant enzymes, the high energy mobilization during fasting caused oxidative stress.
Aquaculture is growing the intensification of production has negative consequences for fish and the environment. In these systems, feed is offered at a high frequency, unlike in the natural environment, which makes it possible to use feed restriction and refeeding cycles. During periods of fasting, fish mobilize energy reserves, and during re-feeding they activate compensatory mechanisms to replenish these reserves. Thus, metabolic changes alter the dynamics of energy production, and two systems may be affected: the immune system and the antioxidant system, which responds to the production of free radicals during the activation of cellular respiration. Considering the above, this study evaluated the metabolic dynamics, innate immune and antioxidant system responses, during feed restriction and re-feeding of pacu (Piaractus mesopotamicus). The fish were subjected to cycles of 3 days of restriction and 2 days of refeeding for 30 days or to 21 days of restriction followed by 9 days of refeeding and, at the end, inoculated with lipopolysaccharide (LPS). The results of this study showed that dietary restriction modulated energy reserves during the 21 days of dietary restriction, and after 9 days of refeeding promoted compensatory growth and recovery of energy reserves. The immune system (leukocyte respiratory activity and lysozyme) was not affected by dietary restriction, but refeeding activated ARL and reduced serum lysozyme concentration. In food-deprived fish, the antioxidant system showed impaired responsiveness. Although there was activation of antioxidant enzymes, the high energy mobilization during fasting caused oxidative stress.
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Palavras-chave
Jejum, Fisiologia, Metabolismo energético, Estresse oxidativo, Pacu (peixe)