Effect of chromium picolinate supplementation on growth performance, serum biochemicacl parameters, and immune status of broilers

Two hundred and forty broiler chicks (one day old), were randomily divided into four equal groups, each group was subdivided to be in doublicate (30 chicks for each). Four levels of dietary &#99;&#104;&#114;omium supplementation (0 control, 800, 1600, and 3200 µg/kg) were provided in the form of &#99;&#104;&#114;omium picolinate throughout the experimental period (6 weeks). The chicks were fed on starter diet (23% CP & 3200 Kcal ME/Kg) for the first 3 weeks and grower- finisher diet (20% CP & 3200 Kcal ME/Kg) through the next three weeks. Body weight and feed intake were determined and feed conversion ratio was calculated. At the end of experiment, blood samples were collected for obtaining clear sera which were used for determination of the total proteins, albumin, globulin, glucose, triacylglycerol, high density lipoprotein (HDL), low density lipoprotein (LDL), phospholipids and non estrified free fatty acids (NEFFAs). Also, liver function enzymes including aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) were determined. In addition, serum samples were used for determination of haemagglutination inhibition titer against Newcastle disease, γ-globulin. IgG and IgM. At end of the experiment, five birds from each replicate were used for determination of carcass traits and composition. The obtained results revealed that feeding high &#99;&#104;&#114;omium levels (1600 and 3200 µg/Kg) significantly increased (p < 0.05) the final body weight and average daily weight gain. However, &#99;&#104;&#114;omium had no effect on feed conversion. The dietary supplements of &#99;&#104;&#114;omium (1600, 3200 µg/Kg) significantly reduced the blood glucose. The total cholesterol level, LDL and NEFFAs. Also, &#99;&#104;&#114;omium supplements (1600 and 3200 µg/Kg) increased serum phospholipids, HDL, total proteins, albumin and globulin. The liver function tests (AST, ALT and GGT) indicated no differences between the different groups. High &#99;&#104;&#114;omium supplementation (1600 and 3200 µg/Kg) increased the y- globulin levels. Haemagglutination inhibition antibody titer against Newcastle vaccine. IgG and IgM were increased with increasing the &#99;&#104;&#114;omium level in the diets. The carcass yield did not affected by &#99;&#104;&#114;omium supplementation (1600 and 3200 µg/Kg). there were decrease in the abdominal pad and increase in breast yield at the level of 1600 and 3200 µg/Kg of &#99;&#104;&#114;omium. The protein percent of carcass was increased and fat percent was decreased while the ash and moisture were not significantly affected. ,