Effect of fed with graded levels of bovine lactoferrin growth performance, serum and mucus lysozyme activity of juvenile Siberian sturgeon

This experiment was carried out to investigate the effect of different levels of dietary lactoferrin on growth performance and innate immune response of juvenile Siberian sturgeon (Acipenser baeri). Fish (26. 3 ± 0. 2 g) were fed with six different dietary lactoferrin including 0، 100، 200، 400، 800 and 1600 mg/kg for 8 weeks. Growth performance was measured at each 2-week interval. After the feeding trail، blood and mucus samples were collected for estimating hematological and immunological parameters. There was no significant difference between treatments in terms of growth performance (weight gain، specific growth rate، feed conversion ratio، condition factor and hepatosomatic index)، during and at the termination of the experiment (P>0. 05). White blood cell counts (WBC) and differential WBC count were not affected by dietary supplementation of bovine lactoferrin (P>0. 05). Mucus and serum lysozyme activities were not significantly influenced by dietary lactoferrin (P>0. 05). Moreover، mucus secretion significantly increased in fish fed 400 mg/kg lactoferrin compared to control group (P<0. 05). In spite of the significant increase of mucus secretion in fish fed dietary lactoferrin، it seems that the possibility of using this ingredient as an immunostimulant for Siberian sturgeon is low، but further studies are needed to find the effect of lactoferrin on other related immunological indices.