اثر متقابل آنزیم کربوهیدراز و ترکیب فیتوژنیک بر عملکرد، قابلیت هضم و خصوصیات کیفی تخم مرغ، مرغ‌های تخمگذار تغذیه شده با سطح انرژی کاهش یافته

Introduction: With the rising cost of high-energy feed ingredients such as oils and cereals, formulating cost-effective poultry diets while maintaining production performance has become a challenge. One strategy to address this issue is to reduce dietary metabolizable energy (ME) levels and compensate by using feed additives like multi-enzymes and phytogenic compounds. Multi-enzymes can improve nutrient digestibility by degrading anti-nutritional factors like non-starch polysaccharides, thereby enhancing gut function and nutrient absorption. Phytogenic compounds, derived from herbs and spices, are known for their antimicrobial, antioxidant, and digestive stimulant properties. However, their efficacy in low-energy diets remains underexplored. Therefore, this study was conducted to evaluate the individual and combined effects of multi-enzymes and a phytogenic compound on the performance, nutrient digestibility, and egg quality of laying hens fed reduced-energy diets.
Materials and Methods: A total of 320 Hy-Line W-36 laying hens, aged 70 weeks, were randomly allocated to eight dietary treatments in a 2 × 2 × 2 factorial arrangements with eight replicates of five birds each, and the trial lasted until 78 weeks of age. The experimental factors included two levels of dietary metabolizable energy (2800 and 2650 kcal/kg), presence or absence of multi-enzyme supplementation (200 g/ton), and presence or absence of a standardized phytogenic compound (0.02%). The eight treatments were: (1) control diet (2800 kcal/kg), (2) control + enzyme, (3) control + phytogenic compound, (4) control + enzyme + phytogenic compound, (5) reduced-energy diet (2650 kcal/kg), (6) reduced-energy + enzyme, (7) reduced-energy + phytogenic compound, and (8) reduced-energy + enzyme + phytogenic compound. Data were collected on feed intake, egg production, egg weight, feed conversion ratio, mortality, nutrient digestibility (using acid insoluble ash marker), and egg quality traits including yolk color, shell strength, and Haugh unit.
Results and Discussion: Hens fed the control diet (2800 kcal/kg) exhibited significantly better (P < 0.05) performance in terms of egg production, egg weight, egg mass, and feed conversion ratio compared to those receiving the reduced-energy diet (2650 kcal/kg). However, the addition of multi-enzymes and phytogenic compounds to the reduced-energy diet significantly improved these parameters. Notably, hens fed the reduced-energy diet supplemented with both enzyme and phytogenic compound had production performance statistically similar to the control group, suggesting that these additives effectively compensated for the energy reduction. Digestibility results showed that enzyme and phytogenic compound supplementation, both alone and in combination, significantly increased (P < 0.05) the digestibility of dry matter, crude protein, crude fiber, and metabolizable energy, particularly in the reduced-energy diets. This enhancement likely stemmed from improved enzyme-substrate interactions, gut morphology, and microbial balance in the gastrointestinal tract. Egg quality traits also benefited from supplementation. Phytogenic compounds improved yolk color due to their natural carotenoid content, and enzyme supplementation contributed to better eggshell strength, possibly by enhancing calcium absorption. A significant three-way interaction among energy level, enzyme, and phytogenic compound was observed for several traits, including egg production, egg mass, FCR, and yolk pigmentation, highlighting a synergistic relationship between these dietary factors.
Conclusions: Reducing dietary energy from 2800 to 2650 kcal/kg negatively impacted the performance, nutrient digestibility, and egg quality of laying hens. However, the inclusion of multi-enzymes and phytogenic compounds mitigated these adverse effects. The combination of both additives was particularly effective in enhancing performance, digestibility, and egg quality in hens fed reduced-energy diets, making these additives viable strategies for cost-effective and sustainable poultry production. These findings underscore the potential of integrating enzyme-phytogenic mixtures into layer diets with lower metabolizable energy to maintain optimal productivity without compromising economic efficiency.