EFFECT OF SPRAYING HATCHING EGGS BY ASCORBIC ACID DURING INCUBATION ON HATCHABILITY, POST-HATCH CHICK GROWTH AND PHYSIOLOGICAL PARAMETERS IN A LOCAL STRAIN OF CHICKENS.

The present study was carried out to investigate the effect of spraying hatching eggs with ascorbic acid (AA) on embryonic mortality, hatchability, growth performance of hatched chicks and some blood constituents as well as, economical efficiency of Silver Montazah local strain chickens. A total number of 1944 hatching eggs were obtained from breeder hens of Silver Montazah strain at 44 weeks of age. Eggs were randomly distributed into 12 treatment groups (162 eggs/group). Each group was divided into three replicates of 54 eggs each. A 3x4 factorial design experiment was performed including three times (4th ,14th or 4th + 14th days of incubation period) and four doses of ascorbic acid , control (without spraying), spraying with distilled water, spraying with 20 g AA/liter distilled water and spraying with 30 g AA/liter distilled water. Post- hatch a number of 105 newly hatched- unsexed chicks were taken from each treatment and separately reared up to 28 days of age to study the effect of incubating treatments on their performance.
The obtained results showed that the percentages of embryonic mortality {medium (8-14 d) and late (15-21d)}, hatchability of fertile eggs, white blood cells (WBC’s) count, Phosphorus (P), body weight (at 28 day of age), body weight gain (from 14-28 days of age) and feed conversion (from 14-28 and 1-28 days of age) were significantly (P≤ 0.05and 0.01) improved for spraying treatments contained either 20 or 30 g AA as compared to the control or distilled water. While, spraying time had no significant effects on percentages of embryonic mortality, unhatched chicks, hatchability of fertile eggs, SRBC’s count, WBC’s count, Ca , P, glucose and T3 in chicks at hatch and at 28 days of age except , SRBC’s count and P value at the late time of Silver Montazah chicks during different times. The relative weights of lymphoid organs and antibody titer against SRBC’S of chicks at 28 days of age were significantly higher in the AA groups than the distil water and unsprayed control.