Phytase-xylanase combo: taking super-dosing to the next level
The study, carried out by scientists at the University of Berlin, found that compared to phytase super-dosing alone, the inclusion of the xylanase resulted in a 4% improvement in broiler bodyweight gain over a 35-day period.
The UK feed ingredients firm was unable to put forward a spokesperson, but Gilson Gomes, AB Vista’s global technical manager for poultry, said in a statement: “This is a gain that is not only statistically significant, but is also economically worthwhile, whether used to boost performance or add to the matrix and further reduce feed costs.”
Super-dosing explained
The vast majority of commercial phytase use today focuses on the reduction of feed costs through sparing of inorganic phosphorus and, to a lesser extent, calcium sources.
The return on investment from a phytase can be as much as 10 to 1. As a result, it is not surprising that the use of the ingredient is almost universal in monogastric diets.
Most pig and poultry producers feed phytases at a fixed rate of 500 FTU per kg. However, in an interview with this publication in June, AB Vista said that feeding at higher levels of 1,000 to 2,000 FTU per kg could bring about an improved feed conversion rate (FCR) in livestock.
The method involves the addition of sufficient phytase to quickly destroy all phytate present in the diet. As phytate is an ‘anti-nutrient’, this will lead to performance improvements in the target animal greater than those expected from the simple release of nutrients due to added phytase.
The company said “benefits in performance, bone strength, fat digestibility and antioxidant status have been found with feeding higher levels with no nutrient sparing beyond the first 500 FTU per kg of feed.”
Xylanase boosts broiler growth
This study suggests that this effect can be augmented by improving the availability of the phytate through the action of xylanase.
The trial compared the performance of a super-dosing optimised phytase (Quantum Blue) and a latest generation single-enzyme xylanase (Econase XT) in wheat-corn-soy fed broilers grown from 0 to 35 days of age. Superdosing with 1500 FTU/kg of the phytase increased bodyweight gain by 3% (2205g versus 2140g) compared to the control diet containing a standard 500 FTU/kg phytase dose (formulated using a phytase matrix of 0.2% calcium, 0.2% phosphorous, 100 kcal/kg AME). Addition of a standard 16,000 FXU/kg dose of the xylanase raised bodyweight gain a further 4% (to 2291g).
“When the target is phytate elimination, improving the availability of that phytate though the action of a well targeted xylanase should be an advantage. This trial confirms that when both enzymes are optimised for efficacy, that advantage translates into a genuine performance gain,” said Gomes.
