Feeding ragworm (Nereis virens Sars) to common sole (Solea solea L.) alleviates nutritional anaemia and stimulates growth |
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| Authors: | Jeroen Kals Robbert J W Blonk Arjan P Palstra Tim K Sobotta Fulvio Mongile Oliver Schneider Josep V Planas Johan W Schrama Johan A J Verreth |
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| Institution: | 1. Institute for Marine Resources and Ecosystem Studies (IMARES), Wageningen University and Research Centre, Yerseke, the Netherlands;2. Livestock Research, Wageningen UR, Wageningen, the Netherlands;3. Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Barcelona, Spain;4. Aquaculture and Fisheries Group, Wageningen University, Wageningen, the Netherlands |
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| Abstract: | Common sole fed with commercial pellets develop anaemia and are restricted in their growth performance. The anaemia can be the result of a difference in feed intake, a nutritional deficiency, an inflammatory response to infection or combinations of these aspects. In this study, it was investigated whether feeding ragworm would alleviate the anaemia and stimulate growth. Sole were fed one of three diets: a commercial feed, a commercial feed treated with ragworm extract or chopped ragworm. By comparing groups, three hypotheses were tested: (1) feeding ragworm alleviates the anaemia and positively affectS the sole's metabolic performance reflected in feed intake, feed efficiency and growth; (2) anaemia is alleviated by a higher feed intake when feeding ragworm and (3) anaemia is caused by an inflammatory response to infection. The sole fed with a commercial diet suffered from anaemia. Feeding sole with ragworm alleviated the anaemia as the average haematocrit level nearly doubled in these fish as compared to fish fed pellets. Investigation of the expression of genes in the liver indicated that the anaemia in sole fed pellets is a nutritional anaemia and not an anaemia due to an inflammatory response. Sole fed ragworm showed improved growth which may be a consequence of the higher haematocrit levels in these fish increasing their oxygen carrying capacity. Addition of ragworm extract to the pellets levelled the feed intake between pellets and ragworm, but did not improve the anaemic state of sole and had only a limited effect on growth. |
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| Keywords: | Solea solea L Nereis virens Sars growth anaemia hepcidin gene expression |
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