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Abstract
This study carried out to investigate the effect of different levels of vitamin C (ascorbic acid) supplementation, calcium and their interaction on performance of broiler chicks under summer condition of Egypt.
A factorial design arrangement (3 X 3) was performed included three levels of calcium (0.7, 1.0, and 1.3 %) during the starter period (1-4 weeks of age) and the finisher period (4 - 6 weeks of age) and three levels of supplemented ascorbic acid (0, 300, 600 mg/kg diet. The basal experimental diets were formulated to contain 0.7, 1.0 and 1.3 % calcium during the starter and the finisher periods. Each diet was fed either without or with ascorbic acid at levels 0, 300 and 600 mg/kg diet.
A total number of 270 unsexed one week old Cobb chicks were randomly distributed into 9 groups (each of 30 chicks). The chicks were not statistically different in average of body weight. Each group was divided into three replicates (each of 10 chicks).
Growth performance, carcass traits, some tibia bone characteristics were studied.
The results obtained can be summarized as follows:
1- Live body weight, body weight gain and feed conversion ratio were not significantly (p<0.05) affected by ascorbic acid supplementation at any level compared to the unsupplemented one. The chicks fed the diet supplemented with 300 mg/kg diet insignificantly improved live body weight, feed conversion and body weight gain.
2- The results obtained showed significant (p<0.05) improvement in live body weight at 4 and 7 weeks of age and body weight gain during all the experimental periods when chicks were fed either 0.7 or 1.0% dietary calcium as compared with those fed 1.30%. On the same time, no significant differences were observed between 0.7 or 1.0%. It’s worth to note that increasing dietary calcium level decreased live body weight and body weight gain.
3- Feed consumption during all the experimental periods were significantly increased (p<0.05) affected by ascorbic acid supplementation at any level compared to the unsupplemented one.
4- No significant differences were observed on feed consumption due to dietary calcium levels during all the experimental periods while feed conversion for both the starter and the whole experimental period improved significantly (p<0.05 or p<0.01) when chicks were fed 0.7% dietary calcium as compared with other treatments.
5- The interaction effects between dietary calcium and ascorbic acid levels were significant (p<0.01) on body weight gain and feed conversion ratio during finisher period. wherever the live body weight and feed consumption didn’t affected by the interaction during starter, finisher and the whole experimental periods. the chicks which fed on diets containing 0.7% calcium level and supplemented with 300 mg vitamin C /kg diet had the best growth performance rates followed by that of 1% calcium with the same level of ascorbic acid.