Poultry producers are experiencing increasing pressure to limit the use of Antibiotic Growth Promoters. NSPase enzymes can be used to promote growth performance, while enhancing nutrient utilization, improving gut health, and reducing production costs,. Xylanase enzymes are an integral part of commercial poultry production for this reason.
The primary objective of this study was to evaluate the efficacy of graded doses of Xylamax, a high-performance xylanase, to improve live performance, minimize the severity of gut lesions and reduce environmental Clostridium perfringens (C. perfringens) of broiler chickens fed standard corn-soy diets and reared under typical broiler production conditions.
Materials and Methods:
2,946 mixed-sex (50% male, 50% female) Ross 708 broiler chicks were randomly assigned to 1 of 6 dietary treatments, with eight replicate floor pens per treatment, and 52 birds per pen. Birds were reared for 42 days on re-used pine litter and fed corn-soy diets ad libitum. Diets were isonitrogenous across treatments and included 22%, 20%, and 19% crude protein in the starter (0-21 days), grower (22-35 days), and finisher (36-42 days) phases, respectively. Metabolizable energy (ME) of positive control standard energy diets were 3000, 3100, and 3200 kcal/kg of feed, in the starter, grower, and finisher phases, respectively. All other treatment diets were formulated at 130 kcal/kg less ME than the standard energy control. The chart below shows the Xylamax inclusions for each treatment.
Standard Energy (SE)
SE – 130 kcal/kg
SE – 130 kcal/kg + 65 g/MT of diet Xylamax
SE – 130 kcal/kg + 83 g/MT of diet Xylamax
SE – 130 kcal/kg + 100 g/MT of diet Xylamax
Key Parameters evaluated were:
• Body-weight gain (BWG)
• Feed conversion ratio (FCR)
• Intestinal lesion scores
• Litter C. perfringens cell count
Results and Discussion:
Reducing ME of standard energy (positive control) diets by 130 kcal/kg significantly reduced (P<0.01) BWG and feed efficiency through 42days. Supplementing energy-deficient diets with Xylamax led to dose-dependent improvements of 42-day BWG and FCR, compared to the un-supplemented (negative) control. When fed diets containing 100 g/MT of diet of Xylamax birds fed energy-deficient diets achieved 42-day body-weights, and FCR equivalent to birds fed the full-energy, positive control diet.
Weight gain and feed efficiency were comparable among birds fed diets supplemented with 83 g/MT of diet of Xylamax. Percent mortality was not affected by treatment and averaged 1.91% across all treatments.
There was no effect on prevalence and severity of intestinal lesions by the level of dietary energy. However, supplementation of Xylamax (at all inclusion rates) significantly reduced (P<0.01) 42-day lesion scores, compared to un-supplemented controls. The abundance of C. perfringens cells present in the litter at 42 days was also significantly reduced (P<0.01) by 100 g/MT of diet of Xylamax supplementation, compared to the un-supplemented controls.
Corn-soy broiler diets may be reformulated to reduce ME by 130 kcal/kg without significantly affecting BWG or FCR when Xylamax is added at an inclusion rate of at least 83 g/MT of diet. At 100 g/MT of diet, Xylamax is significantly at promoting growth and numerically superior at improving FCR, reducing the severity of gut lesions, and reducing environmental pathogen load.
When diets included Xylamax at 100 g/MT of diet we saw significant improvements, such as:
• Increased 42-day body-weight gain (BWG) by 97 g/bird
• Improved 42-day feed conversion ratio (FCR) by 6 points
• Reduced severity of intestinal lesions by 24%
• Reduced litter C. perfringens cell count by 27%
Diets containing Xylamax inclusion at 83 g/MT of diet and 65 g/MT of diet we observed:
• Significant increase BWG at day 42
• Significant reduction of severity of intestinal lesions