Physiological responses to starvation in the European eel (Anguilla anguilla): effects on haematological, biochemical, non-specific immune parameters and skin structures

Abstract

The physiological effects of short-term starvation on some haematological, biochemical and non-specific immune response parameters together with the histological structure of the skin, were investigated in the European eel, Anguilla anguilla. Blood haemoglobin and haematocrit, serum glucose and cortisol, hemolysins, haemagglutinins, and lysozyme in the plasma, kidney and epidermal extract, were measured in fish after 31, 42 and 58 days of starvation, and compared to those of fed fish. Starvation did not affect haemoglobin and haematocrit values, while an increase in glucose and cortisol levels was found in starved eels by day 42. Haemolytic and haemagglutinating activities decreased in starved eels. On the other hand, starvation caused an increase in the lysozyme content in the epidermal extracts, while no significant variations were observed in kidney and plasma. On the whole, no major changes in metabolic, haematological and non-specific immune parameters were observed when short-term (less than 2 months) starvation was applied to the European eel, suggesting an adaptive response to starvation, rather than a typical alarm-stress response, allowing this species to withstand food deprivation.

Effect of starvation on some immunological and biochemical parameters in tinfoil barb (Barbonymus schwanenfeldii)

“…Additionally, plasma lysozyme activity significantly diminished in the 2-week starvation group. Similarly, Caruso et al (2010Caruso et al ( , 2011 found a significant decrease in the plasma lysozyme activity of European eel and blackspot sea bream (Pagellus bogarave) after 31 days starvation. One the other hand, no effect of starvation periods has been detected in lysozyme activity of European sea bass (Dicentrarchus labrax) and red porgy (Caruso et al 2011(Caruso et al , 2012.…”

“…One the other hand, no effect of starvation periods has been detected in lysozyme activity of European sea bass (Dicentrarchus labrax) and red porgy (Caruso et al 2011(Caruso et al , 2012. Moreover, starvation for 42 and 58 days did not significantly affect the lysozyme activity of European eel (Caruso et al 2010). Apparently, the influence of fasting on fish lysozyme activity could vary by the duration of starvation and fish species.…”

“…There are two activation pathways for complement in serum or plasma including classical pathway (CH 50 ) and alternative pathway (SH 50 ). Fish complement activity has been shown to be influenced by starvation (Sakai 1983;Caruso et al 2010Caruso et al , 2012. It is demonstrated that stress (e.g.…”

“…In addition, plasma peroxidase levels were significantly lower in fish fasted for 2 weeks, compared with control and fish fasted for 1 week. Sakai (1983) and Caruso et al (2010Caruso et al ( , 2012 have reported that starvation periods decrease haemolytic activity (SH 50 ) in coho salmon (Oncorhynchus kisutch), rainbow trout (Oncorhynchus kisutch), European eel (Anguilla anguilla) and red porgy (Pagrus Control: fed two times daily to apparent satiation; S1: dprivation for 1 week; S2: deprivation for 2 weeks. Different superscripts on each column indicate significant difference between feeding strategies (P < .05).…”

“…Fish immune responses may be influenced by nutritional states and feed deprivation (Kiron 2012). While a large number of studies have been conducted to investigate the effects of starvation on growth and metabolic responses of fish species of interest for aquaculture (Blasco et al 1992;De Pedro et al 2003;Pérez-Jiménez et al 2007;Costas et al 2011;Falahatkar 2012;Furné et al 2012;Pérez-Jimenez et al 2012;Yarmohamadi et al 2012), few studies have focused on the influence of fasting on the fish immune responses (Sakai 1983;Caruso et al 2010Caruso et al , 2011Caruso et al , 2012.…”