Haematological and biochemical indices of blood in wels (Silurus glanis L.) from intensive aquaculture

The objective of the present study was to determine the values of basic blo od indicators and of biochemical plasma indicators of wels (Silurus glanis L.) intensively bred in warmed power station water without natural feeds. T he study included 8 feeding experiments using 4 imported (ALMA, BioMar) and 4 domestic pelleted feeds with different protein (40 - 49%) and fat (8 - 2 2%) content. The experiment involved 3265 one-year-old sheat fish (Su(1)) o f 209 and 295 g average individual weight (in 1996 and 1997, respectively). Analysed were 56 fish of 15 months (1997) and 17 months (1996) of age, ind ividual weight 1288 and 752 g (1996 and 1997, respectively). The average va lues of blood indicators in fish of all the studied groups were the followi ng: PCV 0.26 l.l(-1), Hb 56.88 g.l(-1), BC 0.78 T.l(-1), Leuko 30.13 G.l(-1 ), MCV 317.65 fl, MCH 68.90 pg and MCHC 0.21 l.l(-1). The leukogram had a l ymphocytic character with a lower number of mature granulocytes. Average va lues of the biochemical blood plasma indicators were as follows: glucose 4. 96 mmol.l(-1) total protein (TP) 29.89 g.l(-1), total lipids (TL) 8.81 g.l( -1) and cholesterol (chol) 4.57 mmol.l(-1). Significant changes (P < 0.05) in hematological indicators were found in fi sh fed the PD2 feed mixture and very significant (P < 0.01) differences in the Chol a TL values in fish fed BioMar and W 97. These data characterise t he adaptation reaction of the internal environment of wels to conditions of intensive aquaculture with warmed water and the nutritional value of used feeds.