Assesing use of non-antibiotic growth promoters in chicken broiler production in Kenya

This study was done to investigate the viability of using organic acids as alternative replacement to antibiotics as in feed growth promoters and for use in managing broiler chickens in poultry farms around Nairobi in Kenya. The first part of this study was a survey and second part consisted of two feeding trials. The survey was conducted in the environs of Nairobi to determine the extent of antibiotic usage as a therapeutic agent and as a growth promoter. Structured questionnaires were administered to feed millers, Agrovets and farmers. It was found that all the Agrovets in the study area stocked antibiotics for use as therapeutic agent and as growth promoters. Both the feed millers and the Agrovets were found to be in possession of antibiotics with components similar to those used in human treatment. It was also found that only 28% of the farmers in the region observe antibiotic withdrawal period. This confirms that there is no proper management in the use of antibiotics in the study area, and the eminent risk of selecting resistant bacteria is not dealt with.

The second part of the study involved two feeding trials of broiler chickens. In the first experiment involving two hundred and forty broiler chickens, a control diet, which contained neither organic acid nor antibiotic, was used. The other three treatments contained Salinomycin sodium (an antibiotic), Acidomix and Avimatrix (organic acids). In the second part of the experiment, an organic acid was introduced in drinking water with treatments similar to the first experiment.

Feed intake, weight gain and FCR were not affected by the treatments (p<0.05). FCR however, decreased when organic acid was introduced in drinking water. The decrease in FCR was accompanied with the reduction in the total bacterial count associated with the organic acid. There was observed a general shift in the composition of bacterial flora, with treatments having lower bacterial count than the control (p<0.05). There was however, no significant difference in lactobacillus and yeast count between the treatment with antibiotics and organic acid. Their counts decreased with introduction of organic acid in the drinking water. Coliforms were lower in all treatments when compared with control both with and without inclusion of organic acid in drinking water.

Villi height was found to be significantly taller than control in treatments containing Salinomycin sodium and Avimatrix. Acidomix gave a villi height shorter than control (p<0.05). Inclusion of organic acid into the drinking water gave greater villi height in all treatments including control. Villi breadth also improved in all treatments and was suppressed with introduction of organic acid into the drinking water.Tunic thickness and glandular area thickness were all significantly improved in treatments without inclusion of organic acid in the drinking water. Generally, inclusion of organic acid in broiler’s drinking water seemed to give a better gut health and improved FCR. However, the same was found to tremendously interfere with the microbial flora of the gut.