نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction: Compared to corn, wheat offers less energy but provides more nutrients. Non-starch polysaccharides in wheat can be challenging for broiler chickens to digest. These complex carbohydrates can increase the viscosity of the intestinal contents, slowing down the digestive process and nutrient absorption. This can lead to reduced growth performance in broilers fed wheat-based diets compared to those fed corn-based diets. Ajwain (Trachyspermum ammi), a member of the Apiaceae family, produces an essential oil that is rich in thymol (35-60%), known for its antibacterial properties. Other significant compounds include para-cymene, γ-terpinene, and carvacrol. These components inhibit both pathogenic and non-pathogenic intestinal species. This antibacterial action helps in maintaining gut health, reducing the load of harmful bacteria, and potentially improving nutrient absorption and growth performance in broilers. While essential oils present a promising alternative to antibiotics, their direct inclusion in animal diets faces limitations due to their hydrophobic, reactive, and volatile nature. Encapsulation techniques, especially those involving nanotechnology, can protect these oils from degradation, improve their stability, and enhance their bioavailability, thereby improving feed consumption and antimicrobial efficacy. Nanotechnology enhances essential oil availability in livestock by increasing surface area. Encapsulated plant essential oils in polymers protect them and improve their antimicrobial properties. Despite the potential benefits, there is a lack of comprehensive research on the effects of encapsulated ajwain essential oil on broiler performance. Therefore, the present study aimed to evaluate growth performance and selected blood biochemical parameters in broiler chickens fed wheat‑based diets supplemented with different forms and concentrations of ajwain essential oil.
Materials and Methods: A total of 1500 one-day-old male broiler chickens were randomly allocated to 12 experimental groups, with five replicates per group and 25 broiler chickens per replicate, following a 2×3×2 factorial arrangement. The factors considered were diet types (corn and corn-wheat), levels of ajwain essential oil (0, 150, and 300 mg/kg of diet), and forms of ajwain essential oil (conventional and encapsulated). Various parameters were measured and recorded, including growth performance, carcass characteristics, and blood biochemical indicators (such as triglyceride, cholesterol, low-density lipoprotein, aspartate aminotransferase, alkaline phosphatase, and alanine aminotransferase) in broiler chickens. Data analysis was performed using the General Linear Model (GLM) procedure of SAS software. Mean separation among treatments was performed using Tukey’s multiple range test.
Results and Discussion: This study investigated the effects of dietary formulation and supplementation with ajwain essential oil (AEO) both free and encapsulated on broiler performance, carcass traits, and metabolic health. The results demonstrate that dietary composition and the method and level of AEO supplementation significantly influenced growth performance, feed efficiency, carcass yield, and health markers in broiler chickens. Broilers fed a corn-wheat-based diet consistently exhibited higher feed intake than those on a corn-only diet throughout all production phases, suggesting improved palatability and enhanced nutrient utilization associated with the mixed-grain formulation. Supplementation of the corn-wheat diet with 300 ppm AEO further increased feed intake during the finisher period, implying a stimulatory effect of higher AEO concentrations on older birds. Body weight gain (BWG) was significantly enhanced by both AEO supplementation and mixed grain feeding, particularly during the starter phase. Notably, AEO at either 150 or 300 ppm improved early BWG, and encapsulated AEO appeared to outperform free oil, likely due to improved stability and targeted release in the gastrointestinal tract. However, during the finisher period, unsupplemented corn-wheat diets resulted in lower BWG compared to any AEO-supplemented or corn-based diet, indicating the necessity of AEO inclusion in late-stage growth for optimal performance. Over the entire trial, AEO supplementation significantly improved overall BWG in corn-wheat fed birds. Feed conversion ratio (FCR) was affected by both diet and AEO level, with the poorest FCR observed in broilers fed the unsupplemented corn-wheat diet during the finisher phase. Optimal FCR was achieved in groups receiving corn plus 300 ppm AEO and corn-wheat plus 150 ppm AEO, highlighting the importance of synergy between base diet and AEO dose. Mortality was, however, higher in the corn–wheat diet supplemented with 300 ppm AEO, suggesting a potential adverse effect associated with this higher inclusion level. The European Production Efficiency Factor (EPEF) was highest in the corn-wheat + 150 ppm AEO group, indicating 150 ppm as the optimal dose in the corn-wheat matrix. Carcass analysis revealed that the corn-wheat diet improved relative carcass and breast weights, while corn diets increased relative weights of the liver, spleen, and gizzard, possibly reflecting metabolic strain. Thigh weight was higher in unsupplemented diets at day 42. Biochemical analysis indicated that encapsulated AEO was more effective than free oil in reducing serum low density lipoprotein (LDL) cholesterol and mitigating elevations in liver enzymes (aspartate aminotransferase, alanine aminotransferase), suggesting improved lipid metabolism and hepatoprotection. Serum triglycerides were lowest in broilers fed corn-wheat + 300 ppm encapsulated AEO. In summary, encapsulation of AEO provided metabolic and hepatic health benefits, and 150 ppm was identified as an optimal supplementation level for performance and health when included in a corn-wheat diet.
Conclusion: This study demonstrates that supplementing corn-wheat-based diets with AEO, particularly in encapsulated form, significantly enhances broiler performance and metabolic health. The corn-wheat combination itself promoted higher feed intake and weight gain compared to corn-based diets. Crucially, AEO supplementation at 150 ppm emerged as the optimal level, synergistically improving weight gain, optimizing the FCR, elevating the European Production Efficiency Factor, and reducing serum LDL cholesterol and key liver enzymes (aspartate aminotransferase, alanine aminotransferase), indicative of better hepatic health. While encapsulated AEO further improved lipid profiles and reduced liver enzyme markers compared to free oil, higher supplementation (300 ppm) increased mortality and elevated liver enzymes. Significant interactions between diet type and AEO levels were evident, particularly for FCR and organ weights. Overall, the integration of corn-wheat diets with 150 ppm encapsulated AEO offers a promising strategy to enhance growth efficiency, carcass yield, and metabolic status in broilers, though higher doses warrant caution due to potential negative impacts on mortality and liver stress markers.
کلیدواژهها English
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