The present study was conducted to investigate the effects of dietary fructo-oligosaccharide (FOS) (0, 1, 2 and 3 %) supplementation on the growth performance, haemato-immunological parameters, cultivable autochthonous (non-adherent) intestinal microbiota and stress resistance of common carp (Cyprinus carpio) fry (3·23 (sem 0·14) g). These parameters were measured after feeding the carp fry with the experimental diets for 7 weeks. Dietary FOS supplementation had no significant effects on the growth performance and food intake of carp fry compared with the control treatment. It also had no significant effects on the following haematological parameters: erythrocyte count; leucocyte counts (WBC); haematocrit; Hb; mean corpuscular volume; mean corpuscular Hb content; mean corpuscular Hb concentration. However, WBC and respiratory burst activity were significantly affected by dietary FOS supplementation. Evaluation of the cultivable autochthonous intestinal microbiota revealed a significant increase in the levels of total viable heterotrophic aerobic bacteria and lactic acid bacteria in fish fed diets supplemented with 2 and 3 % FOS. Furthermore, dietary FOS supplementation significantly increased the survival rate and stress resistance of carp fry compared with the control treatment. These results encourage conducting further research on the administration of FOS and other prebiotics in carp fry studies.

Lipoxygenases are widely distributed in the animal and plant kingdoms. These enzymes catalyse the hydroperoxidation of polyunsaturated fatty acids containing cis,cis-1,4-pentadiene moieties. Multiple isoenzymes, with different biochemical properties and tissue distribution, have been described for many plants. Lipoxygenases occur in vegetative tissues, but also accumulate in various seeds, and especially in leguminous seeds. Although several functions have been proposed for vegetative lipoxygenases, the roles of seed lipoxygenases remain enigmatic. In this review we discuss whether physiological functions assigned to vegetative lipoxygenases can be extended to seed isoforms.