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The effect of food deprivation and refeeding on the liver, thyroid hormones and transthyretin in sea bream

2000; Wiley; Volume: 56; Issue: 2 Linguagem: Inglês

10.1111/j.1095-8649.2000.tb02112.x

1095-8649

Deborah M. Power, Jéssyca Maria França de Oliveira Melo, Cecília R.A. Santos,

Meat and Animal Product Quality

There was a significant reduction in body weight of sea bream Sparus aurata and the hepatosomatic index after 3 weeks food deprivation. Liver biochemical indices and morphology were altered by food deprivation, there was a loss of eosin staining in hepatocyte cytoplasm and the appearance of large depleted vacuoles. Cell and nuclear area were significantly reduced ( P <0·001) and did not return to control values after 1 week of refeeding. The water, lipid, glycogen and protein content of the liver was significantly reduced by 3 weeks fasting but recovered rapidly after 1 week refeeding. Food restriction also had a marked effect on circulating thyroid hormones and the concentration of plasma T 3 (33·98±12·47 ng ml ‐1 ) and T 4 (16·54±9·5 ng ml ‐1 ) was significantly ( P 0·001) lower than the control (66·52±13·4 and 56·83±7·3, respectively). Refeeding for 1 week restored circulating T 3 ( P< 0·05) close to control levels but did not significantly affect the concentration of T 4 . Northern blotting with an homologous probe for transthyretin (TTR) demonstrated clearly the expression of a single mRNA transcript of 0·7 kb for this protein in the liver. The level of TTR message was substantially reduced below control levels in the liver of fasted fish and 1 week refeeding failed to restore expression.