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| dc.contributor.author | Birilie, Endalkachew | |
| dc.date.accessioned | 2026-10-08T06:17:36Z | |
| dc.date.available | 2026-10-08T06:17:36Z | |
| dc.date.issued | 2025-12 | |
| dc.identifier.uri | http://ir.bdu.edu.et/handle/123456789/17423 | |
| dc.description.abstract | The aim of this dissertation was to assess the availability and utilization of organic acid feed additives in commercial chicken production and their effects on the production and economic performance of Bovans Brown layers and Cobb500 broilers. In the survey study, an assessment was conducted on the availability and utilization of organic acids (OAs) in urban and peri-urban commercial chicken farms of Bahir Dar and Gondar cities in Northwest Ethiopia. A cross-sectional study using a semi-structured questionnaire survey and direct observation on the availability and utilization of OAs as feed additives was employed with a total of 211 commercial chicken farms. Quantitative data were analyzed using descriptive statistics, while qualitative data were analyzed thematically to support quantitative findings. The survey results reveal that OAs are not currently utilized in commercial chicken production within the study areas. All participant (100%) indicated a lack of knowledge about OAs as feed additives, highlighting a complete lack of information among commercial chicken producers. The second study elucidated the potential of dietary citric and malic acid supplementation on growth performance and economic efficiency by replacing conventional antibiotics in Cobb500 broiler chickens. This study used a completely randomized design (CRD) consisting of five treatments with four replicates each. A total of 280 one-day-old chicks were randomly assigned to 5 treatment groups, consisting of 56 chicks per treatment, and further replicated four times with 14 chicks per replicate. The experimental treatments were a basal diet without additives (T1), 60 mg/kg oxytetracycline (T2), 16 g/kg citric acid (T3), 8 g/kg malic acid (T4), and a mixture of 8 g/kg citric acid and 4 g/kg malic acid (T5). Dose-level antibiotics and OAs were determined based on previous studies.The results revealed that the average daily weight gain of chicks was significantly (P<0.05) different among the treatments during the starter and grower phases. The T3, T4 and T5 groups presented better (62.09, 61.98, and 64.30 g) average weight gain than the T1 group (59.58 g), whereas the mixed OAs mixture showed comparable results to the antibiotic group (64.06 g) in terms of daily weight gain during the overall experimental period. Broilers receiving citric and malic acids showed improved feed conversion ratios. Diets containing a citric and malic acid mixture produced the highest dressed carcass yield (P < 0.05), which was comparable to that of the antibiotic group. Mixed acid group achieved superior relative economic efficiency. The third experiment described the effects of dietary citric and malic acid supplementation on laying performance, egg quality traits, and economic efficiency of commercial Bovans Brown layer hens. This study used a completely randomized design. A total of 260 25-week-old layer hens weighing an average initial body weight of 1609 ± 18.5 g were obtained from the poultry farm of Bahir Dar University and randomly assigned to 5 treatment groups, each with 4 replicates. Experimental layer hens were acclimated to the experimental diets for 7 days and were fed for 120 days. The treatments consisted of basal diets without any additive (T1), with 30 mg of oxytetracycline (T2), 16 g of citric acid (T3), 8 g of malic acid (T4), and a combination of 8 g of citric acid and 4 g of malic acid (T5) per kg of the basal diet. The inclusion levels of additives were selected based on the published literature. The results revealed a significantly higher difference (P<0.001) in hen-day egg production, egg quality traits, and FCR. Layer hens fed OA diets improved the hen-day egg production by 85.51% to 86.54% compared to T1 (77.75%) and T2 (80.07%). Overall, T5 exhibited better performance in terms of FCR, albumin weight, egg mass, total return, and net profit. T5 improved profitability by 13.26% and 11.82% and REE by 16.83% and 17.40% more than T1 and T2, respectively. In conclusion, dietary supplementation with a mixture of 8 g/kg citric acid and 4 g/kg malic acid effective alternative strategy to replace antibiotic feed additives, in broilers, and layer chickens. Therefore, the incorporation of this mixture into broiler and layer production systems is recommended. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | Animal Nutration | en_US |
| dc.title | Availability and Utilization Practices of Organic Acid Feed Additives in Commercial Chicken Production System and Their Effects on Production and Economic Performance of Bovans Brawn Layers and Cobb500 Broilers | en_US |
| dc.type | Dissartation | en_US |
