Authors : M.B. Magzoub, H.A. Al-Batshan, M.F. Hussein, S.I. Al-Mufarrej and M.Y. Al-Saiady
Abstract: This study was undertaken to determine the effect of dietary Chromium (Cr) supplementation on performance, body chemical composition, plasma glucose, Hepatosomatic Index (HSI) and liver glycogen in hybrid tilapia (Oreochromis niloticus x O. aureus). Cr-yeast or Chromic Oxide (Cr2O3) were added to fish feeds at the rates of 1 or 2 mg kg-1 while control fish received an unsupplemented diet. About 1400 fish (avg. weight 18.6 g) were randomly assigned to 5 feeding regimens, each consisting of four replicates. Each replicate was reared separately. Body Weight (BW), Feed Intake (FI), Growth Rate (GR) and Feed Efficiency Ratio (FER) were measured at days 14, 28, 42, 56, 70 and 84. Chemical composition, HSI and liver glycogen were determined at days 0, 30 and 60. Plasma glucose was measured after starving the fish for 24 h and at 1, 2, 3, 4, 6, 8 h after feeding. The results showed increased BW, FI, GR, FER, total protein, ether extract, gross energy, plasma glucose and liver glycogen and decreased ash percent in all groups. Comparison of the overall means of these variables in different feeding groups showed that BW, FI, GR and FER were significantly lower in fish receiving 2 mg kg-1 Cr-yeast while overall mean values of ether extraction and gross energy were significantly higher in fish receiving 1 mg kg-1 Cr2O3. On the other hand the highest overall mean value for liver glycogen was recorded in fish receiving 2 mg kg-1 Cr. No significant changes were observed in moisture, ash, total protein, plasma glucose or HSI. These findings indicate that the inclusion of Cr in fish feeds can lead to improvement of tilapia chemical composition and physiology, namely ether extract, total energy and liver glycogen.
M.B. Magzoub, H.A. Al-Batshan, M.F. Hussein, S.I. Al-Mufarrej and M.Y. Al-Saiady, 2010. The Effect of Source and Level of Dietary Chromium Supplementation on Performance, Chemical Composition and Some Metabolic Aspects in Hybrid Tilapia Fish (Oreochromis niloticus x O. aureus). Research Journal of Biological Sciences, 5: 164-170.