A total number of 198 Silver Montazah strain birds (180 hens and 18 cocks) 24-wks-old were used in this experiment up to 36 wks. of age was divided into two experimental groups (90 hens and 9 cocks per each group). The birds of the 1st group were individually weighed and randomly divided into 3 equal treatments (30 hens and 3 cocks in each) with three replicates (10 hens and 1 cock in each) with almost similar initial average body weight. Replicates were randomly housed in floor pens (280 cm long x 220 cm wide). The 1st group of birds (90 hens and 9 cocks) was divided to 3 treatment groups, the 1st treatment group was fed the basal diet without supplementation and served as control (T1), the 2nd and 3rd treatment groups were fed the basal diet supplemented with 8.25 and 11.00 mg pyridoxine/kg diet (T2 and T3), respectively. At the end of the experiment (36 wks. of age), a total number of 300 hatching eggs were collected from experimental groups (100 eggs in each treatment). At the same time (36 wks. of age), the second 300 hatching eggs were collected from the same breeder flock fed the basal diet without supplementation and incubated. At the 18th day of incubation, 300 eggs were divided into three treatment groups (100 eggs in each). The 4th treatment group was injection with 0.2 ml saline solution (T4). The 5th and 6th treatment groups were injected into amniotic sac through the air sac with 300 and 400µg pyridoxine, respectively.
The results obtained could be summarized as follow: Results showed significant (P≤0.05) differences among treated groups in embryonic mortality, hatchability percentage, chick weight and chick quality at hatch. The best values of embryonic mortality, hatchability percentage and chick weight at hatch were recorded by pyridoxine injection at different doses compared with either un-supplemented or un-injected pyridoxine treatments which recorded the worst values. The best (P≤0.05) values of percentage of grade A chicks were recorded by pyridoxine injection at different doses treatments when compared with other treated groups. The highest (P≤0.05) values of plasma total protein, globulin, calcium, phosphorus , T3 and T4 concentrations and albumin/globulin ratio of chicks at hatch day were recorded by pyridoxine injection, especially at the high level (400 µg) when compared with either supplemented or un-injected pyridoxine groups.
In conclusion, in - ovo injection of pyridoxine at level 400µg to laying eggs at 18 days of incubation may be a practical and beneficial procedure for improving the hatchability traits and the early post hatch physiological responses as indicated with better blood biochemical and metabolic hormones expression.