Influence of Adding Organic Chromium in Diet on Productive Traits, Serum Constituents and Immune Status of Bandarah Laying Hens and Semen Physical Properties for Cocks in Winter Season

This study was to assess the effects of organic chromium supplementation on productive traits, some serum constituents and immune status of Bandarah laying hens and semen physical properties for cocks in winter season. The mean value of temperature and relative humidity during that period in the house was 12.3± 2.2°C and 67.4 ± 6.5%, respectively. One hundred and fifty laying hens and forty cocks of Bandarah local strain at 32 weeks of age were used during winter season and distributed randomly in individual cages to five treatment groups (30 hens and 8 cocks in each group). The basal diet was supplemented with 0 (Control), 250, 500, 1000 and 1500 ppb chromium (Cr) which produced from chromium yeast. The experiment was terminated at 44 weeks. The results indicated that Cr had no significant effect on overall mean of body weight and feed consumption for hens and cocks, while, significantly (P≤0.05) improved egg production, egg weight, albumen percentage, egg shell percentage, egg shell thickness, Haugh unit and yolk index. The interaction between Cr and age was significant for egg production, where, the highest egg production was observed at 44 age of weeks for 1500 ppb Cr. Also, overall means of egg weight was significantly (P≤0.05) increased with the increase of hens age especially at 44 weeks of age. Moreover, Cr had no significant effect on egg shape index, while, yolk weight percentage was decreased compared with the control group. Increased supplemental Cr linearly significantly (P≤0.05) increased the primary or secondary antibody titers against SRBCs, serum total protein, globulin, calcium and insulin concentrations, whereas, total lipids, cholesterol, glucose and corticosterone levels significantly decreased. Serum albumin values were not significantly affected in all Cr supplementation groups compared with control. In addition, supplementation of Cr significantly (P≤0.05) improved semen physical properties and seminal malondialdehyde concentration with one exception the lowest level of Cr (250 ppb) did not change ejaculate volume significantly compared with those for control group. Regardless of Cr supplementation, overall means of semen physical properties and seminal malondialdehyde were significantly (P≤0.05) affected by cock's age. Generally, fertility and hatchability percentages significantly (P≤0.05) increased with the increase of dietary Cr levels. In conclusion, supplementation the chicken diet with 1500 ppb Cr is recommended especially in winter season for improving most of the previous mentioned productive traits, immune response, semen quality, fertility and hatchability. Key Word: organic chromium, egg production, blood constituents, semen, malondialdehyde, cold