Physiological stress responses in the warm-water fish matrinxã (Brycon amazonicus ) subjected to a sudden cold shock

Abstract

The present work evaluated several aspects of the generalized stress response [endocrine (cortisol), metabolic (glucose), hematologic (hematocrit and hemoglobin) and cellular (HsP70)] in the Amazonian warm-water fish matrinxã (Brycon amazonicus) subjected to an acute cold shock. This species farming has been done in south America, and growth and feed conversion rates have been interesting. However, in subtropical areas of Brazil, where the water temperature can rapidly change, high rates of matrinxã mortality have been associated with abrupt decrease in the water temperature. Thus, we subjected matrinxã to a sudden cold shock by transferring the fish directly to tanks in which the water temperature was 10 o C below the initial conditions (cold shock from 28°C to 18 o C). After 1h the fish were returned to the original tanks (28ºC). The handling associated with tank transfer was also imposed on control groups (not exposed to cold shock). while exposure to cold shock did not alter the measured physiological conditions within 1h, fish returned to the ambient condition (water at 28º C) significantly increased plasma cortisol and glucose levels. exposure to cold shock and return to the warm water did not affect HsP70 levels. The increased plasma cortisol and glucose levels after returning the fish to warm water suggest that matrinxã requires cortisol and glucose for adaptation to increased temperature.Key words: matrinxã, cold shock, stress, HsP70.Respostas fisiológicas ao estresse do peixe de águas tépidas matrinxã (Brycon amazonicus) submetido à queda brusca de temperatura resumo o presente trabalho avaliou as principais respostas fisiológicas e celulares [endócrino (cortisol), metabólico (glicose), hematológico (hematócrito and hemoglobina) e celular (HsP70)] ao estresse de um peixe de águas tépidas, o matrinxã (Brycon amazonicus), quando submetido a um choque térmico frio abrupto. essa espécie vem sendo amplamente cultivada na América do sul por apresentar excelentes índices zootécnicos de crescimento e conversão alimentar. entretanto, os produtores rurais encontram limitações no manejo do matrinxã, quando criado em regiões mais frias que sua região de origem, a Bacia Amazônica. Assim, o matrinxã foi submetido a um choque frio através da transferência direta dos peixes para tanques com água fria a 18°C. Após 1h, esses peixes retornaram a suas caixas de origem a 28°C. o manuseio de peixes necessário para conduzir o choque térmico experimental foi também imposto aos grupos controle, sendo, entretanto, evitada a água fria. o matrinxã demonstrou claros sinais de estresse fisiológico durante os procedimentos experimentais. Porém, essas respostas não foram associadas ao choque frio, mas sim ao choque quente por ocasião da volta dos peixes para as caixas de origem. As respostas primárias e secundárias de estresse foram evidentes através das análises plasmáticas de cortisol e glicose. Já o hematócrito, a hemoglobina e as expressões da proteína de estresse, HsP70, não foram afetadas. nossos resultados sustentam qu...

Effect of β-Glucan on cold-stress resistance of striped catfish, Pangasianodon hypophthalmus (Sauvage, 1878)

“…In fact, a lack of response would evidence the inability to adapt to cold, which could eventually lead to fish death. Indeed, mass mortality of matrinxã due to a sudden decrease of water temperature has been previously reported in aquaculture facilities close to subtropical areas (Inoue et al 2008). In contrast, the partial mortality observed in the control group indicated that fish were indeed stressed despite the lack of an endocrine response.…”

Physiological responses and HSP70 mRNA expression of GIFT strain of Nile tilapia (Oreochromis niloticus) under cold stress

“…Earlier investigations have shown that the increased expression of HSP70 in brain tissue was previously linked to cold stress in channel catfish (Ju, Dunham & Liu ) and found the abundance of HSP70 mRNA in muscle of channel catfish reared at low temperature on day 14 and 28 of the study (Weber & Bosworth ). No increase in HSP70 mRNA levels were found in Atlantic salmon exposed to a 2 h, 12°C cold shock (from 16°C to 4°C) (Zarate & Bradley ), and changes of water temperature did not affect HSP70 levels in the Amazonian warm‐water fish matrinxã ( Brycon amazonicus ), while exposed to cold shock (18°C) and returning to the warm water (28°C) (Inoue, Moraes, Iwama & Afonso ). In addition, the expression of HSP70 mRNA in liver of fish showed more volatility during cold stress, compared with that in muscle.…”

Effect of Selenium Incorporated in Feed on the Hematological Profile of Tilapia (Oreochromis niloticus)

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