According to the results obtained on feed intake in different periods, it can be seen that the Aloe vera groups have the highest level of feed intake compared to the control group and this leads to increased body weight gain in these groups in comparison to the control group. Olupona et al. (2010) reported increased feed intake in groups which were treated by Aloe vera gel solved in water (15, 20, 25, and 30 cm3/dm3) as body weight gain rose. Similarly, the present study shows increased feed intake in the 2-percent Aloe vera gel with raised level of body weight gain. Increased feed intake in Aloe vera groups can be attributed to changes in feed taste and stimulated appetite since, as reported by Windisch et al. (2008), phylogenic substances (as additives to birds’ feed) can improve taste of diet. Furthermore, Wenk (2002) argued that herbs can stimulate appetite and endogenous secretions which, in turn, improve grower performance. on the other hand, our experiments showed that Aloe vera groups consumed more feed compared to the antibiotic groups both in the grower period (days 25 to 42) and during the total experiment period (days 0 to 42). Guo et al. (2004) observed that food consumption level in chickens treated by Chinese herbs added to their diet was higher than this level in chickens fed by viriginiamycin mixed with their food.
In general, increased body weight in different periods show larger body weight gains in the antibiotic groups compared to other groups. Among the experimental groups, the 2-percent Aloe vera group had better body weight gain compared to other Aloe vera groups and the control group, showing no significant difference from the antibiotic group. On the other hand, findings obtained in studies on treatment of broilers with viriginiamycin suggest that this antibiotic can increase broilers’ body weight gain compared to control group (Bafundo et al., 2003; Miles et al., 2006) which is in line with the findings of the present study.
In the present study, on feeding broilers with Aloe vera gel added to diet, we observed that although Aloe vera groups showed improved body weight gain compared to the control group, however, no significant difference was observed in feed conversion ratio. Moreover, the Aloe vera groups had higher feed conversion ratio than the antibiotic group. Olupona et al. (2010) reported that Aloe vera gel added to water (15, 20, 25, and 30 cm3/dm3) resulted in significant final body weight gain as well as in weekly body weight gain compared to control group. In addition, Aloe vera groups showed higher feed conversion ratio than the control group, but showed no significant difference from each other.
Studies on the effects of Aloe vera powder and alcohol and water extracts as well as on the effects of mixture of alcohol and water extracts of Aloe vera gel and chlortetracycline on broilers shows that 600 mg of Aloe vera water extract results in significant increased body weight of broilers, in the third...