EFFECT OF VITAMIN ''C'' SUPPLEMENTATION ON SOME PHYSIOLOGICAL PARAMETERS OF OSTRICH EXPOSED TO EARLY HEAT STRESS OF TEMPERATURE

Twenty four ostrich (one week old), from the breeding flock in Nuclear Research Center, AEA, Egypt (April 2008), were used in this study. The effect of vitamin Csupplementation on the physiological responses of ostrich exposed to high temperature at early age was investigated. All chicks were exposed to 24 hours light per day. The birds were fed starter ration ad libitum (22 % protein and 2680 K cal ME/kg). Birds were divided to equal three groups. The first group was fed the previous starter ration and exposed to normal ambient temperature (22 ± 10C) (TN group) while the second group was fed the same starter diet and exposed to high environmental temperature (38 ± 10C) (HS group). The third group was fed the previous starter diet by adding 250 mg of L-ascorbic acid/kg diet and exposed to high environmental temperature (38 ± 10C) (VC group). Daily feed consumption and mortality percentage were determined. Blood hematological parameters such as total red blood cell counts (RBC), white blood cells counts (WBC), hemoglobin concentration (Hb), paced cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were determined. Also, some physiological blood parameters such as serum total protein (TP), albumin (Alb), globulin (Glob), calcium (Ca), phosphorus (Ph), uric acid (UA), creatinine (Cr) and triiodothyronine hormone (T3) were measured. Also, A/G ratio was calculated. It was found that feed consumption was significantly decreased when bird was exposed to high ambient temperature while it was significantly elevated in VC group. Mortality percentage was significantly increased when birds were exposed to high environmental temperature while it was reduced with vitamin Csupplemented. Both RBC and WBC counts and both of MCV, MCH and MCHC were significantly decreased due to heat stress condition while there were non-significant differences between TN and VC groups. Hb level was reduced significantly by exposure to heat stress in VC group and high significant reduction was recorded in HS group as compared with TN group. PCV showed non-significant difference between VC and HS groups and both of them were significantly reduced as compared with TN group. Serum TP, Alb, Glob levels and A/G ratio were significantly decreased when birds were exposed to high environmental temperature (HS group) as compared with TN group while there was non-significant difference between both TN and VC groups. Serum uric acid and creatinine levels were significantly increased in VC group and high significant increase in HS group as compared with TN group. Calcium and phosphorus concentrations were significantly decreased by heat stress as compared with the TN group while there was non-significant difference between both TN and VC groups. The level of T3 hormone was significantly reduced in birds of HS group than VC group and both of them showed significant decrease in T3 concentration than the TN group