M.B.  Magzoub, H.A.  Al-Batshan, M.F.  Hussein, S.I.  Al-Mufarrej, M.Y.  Al-Saiady, 
    The Effect of Source and Level of Dietary Chromium Supplementation on Humoral Antibody Response and Blood Chemical Parameters in Hybrid Tilapia Fish (<I>Oreochromis niloticus </I>x <I>O. aureus</I>),
    Research Journal of Biological Sciences,
    Volume 4,Issue 7,
    2009,
    Pages 821-827,
    ISSN 1815-8846,
    rjbsci.2009.821.827,
    (https://makhillpublications.co/view-article.php?doi=rjbsci.2009.821.827)
    Abstract: This study was undertaken to determine the effect of dietary chromium supplementation on humoral antibody response and some blood constituents in hybrid tilapia fish (<I>Oreohromis niloticus x O. aureus</I>). Cr-yeast or Chromic Oxide (Cr<SUB>2</SUB>O<SUB>3</SUB>) were added to fish feed at the rates of 1 or 2 mg kg<SUP>-1</SUP>, while control fish received unsupplemented diet. Three hundred and forty fish (Avg. weight 37.8 g) were randomly assigned to 5 feeding regimens with two replicates each. Each replicate was reared separately. The fish were immunized with Sheep Red Blood Cells (SRBCs) at 0 day and re-immunized at 30 days of the experiment to determine primary and secondary humoral antibody responses, respectively. Blood samples were collected from 15 fish/replicate at 0 and 25 days to determine blood plasma constituents and at 5 days intervals during primary and secondary immunization up to 50 days to determine anti-SRBC antibody titers. The results shown decreased plasma glucose and increased plasma cholesterol concentrations at 25 days compared to 0 days in all groups. Increased triglyceride levels was noted in fish receiving Cr<SUB>2</SUB>O<SUB>3</SUB> (1 mg kg<SUP>-1</SUP>) and decreased albumin: globulin ratio in those receiving Cr yeast (2 mg kg<SUP>-1</SUP>) at 25 days (p<0.05). No significant changes were observed in total protein, albumin and total globulin concentrations due to either Cr treatment or feeding duration. Anti-SRBC antibody titers were significantly higher in Cr-supplemented groups versus control, with highest titers in fish receiving 2 mg kg<SUP>-1</SUP> Cr-yeast supplement during secondary immunization. These findings indicate that the inclusion of Cr in the feed significantly augments humoral antibody response of tilapia.
    Keywords: Chromium supplementation;tilapia fish;blood parameters;immune response;SRBC