Abstract:
The use of antibiotic growth promoters (AGPs) in poultry may induce antibiotic resistance with risk of accumulation of harmful residues in poultry products, thereby compromising poultry and human health. Apple cider vinegar (ACV) and garlic are phytogenic substances which have been gaining considerable interest due to their ability to improve performance. This study investigated growth promoting effects of drinking-water supplemented with ACV and garlic extract on broilers. A total of 390, day-old Ross broiler chicks were housed in an open, deep litter house divided into 30 pen partitions, each measuring 2.3 m2, to which treatments were allocated in a randomized 2 (sex) x 5 (additives) factorial experiment. Experimental units were allotted to antibiotic free diet plus untreated drinking water (Negative control (NC), antibiotic free diet plus ACV treated drinking water (T1), antibiotic free diet plus garlic treated drinking water (T2), antibiotic free diet plus ACV+garlic treated drinking water (T3) or antibiotic fortified diet plus untreated drinking water (positive control (PC). The experiment was replicated three times. The test period started at the age of 15 days and consisted of two phases: grower (15-28 days of age) and finisher (29-42 days of age). All data were subjected to analysis of variance (ANOVA) using the General Linear Model (GLM) procedures of SPSS. Where main effects were significant, Tukey’s test was used to separate the means. Males had higher feed intake than females (P<0.05) in all growth phases. Weight gain, FCR and mortality of the birds was not affected by sex (P>0.05) in all growth phases. Birds on the PC gained more weight (P<0.05) than birds on T1, T2, T3 and NC during all growth phases. Grower-phase feed intake was similar across treatments (P>0.05), while birds on the PC consumed more feed (P<0.05) during finisher phase than birds on the NC and on ACV and garlic additives. Birds on the PC had a lower grower-phase FCR (P<0.05) than birds on T1, T2, T3 and NC, though with lower FCR during finisher phase to birds on T1 and T3. Mortality was similar for all treatment (P>0.05) throughout the experiment. Dressing percentage was similar across sexes (P>0.05). Birds on the NC exhibited a lower dressing percentage (P<0.05) than all others. Meat
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pH was higher in male birds (P<0.05), and was not affected by additives (P>0.05). Gut digesta pH, proventriculus weight, gizzard weight, gastrointestinal tract length across sexes were not affected by treatment (P>0.05). Birds on the PC had a higher liver weight (P<0.05) than all others, and higher spleen weights than birds on T2 (P<0.05). In conclusion, in the current study, ACV and or garlic additives did not benefit broiler performance.
