Objective: To evaluate the effects of different levels of dietary
vitamins C, E and fat (sunflower oil) on the performance, carcass
yield and mortality rate of heat-stressed broiler chick. Design: 2x2x3 factorial trial.
Animals: Five hundred seventy six day-old male broiler chicks
Procedure: The experiment was started at one day old of age and
lasted to 49 days of age.
Statistical analysis: All birds were kept under a consistent temperature of 35.5 to 36.5 from 10:00am to 20:00pm throughout
the experimental period. In respect to existance of different levels
of dietary vitamins C (0 and 250 ppm), E (0 and 288 ppm) and fat (0, and 5% sunflower oil), 9 experimental diets contain same levels of metabolizable energy, protein and other nutrients were
formulated and their effects on the performance, feed intake, carcass yield and mortality rate of heat-stressed broiler chicks were compared. All data were subjected to statistically analysis of variance using the General Linear Models procedure of SAS® software(1990).
Significant differences among treatment means were separated by
Duncan’s new multiple range test with a 5% level of probability.
Results: Neither vitamin C nor vitamin E had significant effects on feed intake, body weight and feed conversion throughout the experimental period carcass and abdominal fat percentages at the
end f the experimental period. However, chicks that were fed diets containing vitamins C, E or fat had a notable lower mortality than control’s group. On the other hand, feed intake, body weight, and feed conversion in total experimental period (0 to 49 d of age) .were improved accompanied by increasing dietary fat from 0 to
2.5 or 5%, significantly (P<0.05). Conclusion: The results of this experiment indicated that dietary
supplementation of vitamins C and E (250 and 288 ppm, respectively)
and dietary added fat can be recommended for reducing of total
morality and remarkable increase of chickens’ performance and
livability in heat stress conditions, respectively. J. Fac. Vet. Med. Univ. Tehran. 58, 2: 125-128, 2003.