Many challenges are facing the broiler industry. Antibiotics have been used in animal feed to mitigate the negative effect from various sources; however, increased legislation restrictions and consumer demands are increasing pressure to limit antibiotics usage in the poultry production. The industry is continuing to investigate different approaches to protect chicken health while maintaining the feed cost load and improving desired growth efficiency.
One way to do that is through enzymes such as xylanase, which can reduce the anti-nutritional factors present in feed ingredients. Xylan is the most abundant of non-starch polysaccharides (NSPs) that can be entrapped nutrients within fiber-rich cell walls, which reduces the overall feed value. A 3,000 kcal/kg diet has 450 kcal/kg of undigested energy. NSPs can also reduce feed intake and nutrient utilization. This undigested xylan is a predisposing factor to necrotic enteritis, which increases inflammation, oxidative stress and tissue damage, as well as leads to a higher gut maintenance energy requirement.
Supporting a healthy gut:
- Increases nutrient absorption
- Improves immune response
- Positively impacts growth performance
With the additional challenge of Antibiotic Growth Promotors (AGPs) being banned, the industry has evolved beyond just improving digestibility and cost savings to needing a solution that also benefits animal wellness, especially for gut health.
Probiotics have become more popular to use in feed additives, especially the bacillus species, a group of bacteria known to be a suitable candidate for probiotics in feed due to its high tolerance to environment.
Direct –Fed-Microbials (DFMs, Probiotics) have several advantages:
- A high tolerance to environment
- Improved gut function and protection, which improves nutrient absorption and immunity that impacts growth performance
- Reduced pathogen load
- Reduced environment contamination
The team at BRI began developing a unique solution that can deliver consistent performance results and demonstrate a collective benefit for direct-fed microbials and xylanase. At BRI, we called this collective benefit from the energy released by the action of the xylanase enzyme, with a prebiotic effect of its unique xylanase action and a probiotic effect from the DFMs, along with the commensal beneficial microbiota to provide a “Zymbiotic” effect.
In a corn-based study, the birds were challenged with recycled litter, which is a common practice in the U.S., and a nutrient challenge of energy reduction. Positive results were observed in growth performance, energy digestibility and gut function parameters such as lesion score and litter clostridium load and the results were comparable to the AGP treatment.
Sorghum-Based Diet Experiment
BRI then investigated whether a sorghum-based diet would yield similar results.
In this experiment, BRI used Cobb 500 mixed-sex chicks. Their diet had three phases: starter (1-21 days), grower (22-35 days), and finisher (36-42 days). 1,350 birds with 50 chickens per pen and 9 replicated pens per treatment were fed sorghum and soybean meal to formulate treatments with two different levels of metabolized energy. The third was a positive control formulated with standard energy level based on the Cobb recommendation, a negative control with a reduction in energy, and the negative control of the FM and xylanase blend. The chicken body weight and feed intake were weighed and recorded weekly. Gut function parameters were measured at the end of each feeding phase and intestinal morphology was sampled on day 22.
Body weight differences were observed starting from 21 to 42 days of age. The results were as expected. From previous trials, the DFM and xylanase blend would normally contribute about 80 kcal energy in a corn/soy-based diet, which is mainly from the xylanase inclusions. The reduction of the 130 kcal in the negative control significantly increased feed conversion ratio compared to the positive control while the addition of the DFM and xylanase blend recovered feed conversion ratio to a similar level as the positive control. These birds were raised in hot weather without feed restriction, therefore the positive and negative controls saw 8.5% mortality, while addition of DFM and xylanase reduced mortality by 1.3%. At the end of the 42-day feeding trial, the carcass weight of Enzapro-treated birds were similar to the positive control, and the carcass percentage and breast percentage were the same between treatments.
For gut function parameters, there were no differences between the treatments, due to the birds being raised on fresh litter.
Intestinal morphology samples were collected on day 22, and the Enzapro had the tallest villi of the three treatments. When comparing the crypt depth and villi density, all three are very similar. This number reported the capacity of the absorption area of the ileum. The positive control had 6.05, the highest amount, followed by Enzapro, which was significantly higher than the negative control.
This result reflects the performance result observed in body weight and feed conversion ratio.
The combination of Bacillus spp. and xylanase supplemented to sorghum-based diets can:
- Recover partial growth performance under 130 kcal energy reduction diets.
- Improve ileum villi height and absorption area.
For more information about Enzapro, visit www.briworldwide.com/products/enzapro.