Opportunities to improve financial returns with targeted enzyme applications


By Gilson Gomes, Global Technical Manager, AB Vista


Over recent years poultry producers have come under greater pressure from authorities and consumers. One example is the ban on antibiotic growth promoters and the demand for free-range broilers and layers. Whilst these initiatives have been taken to safeguard public health and animal welfare, they increase the pressure on poultry producer profitability. Producers are thus forced to seek alternative sustainable ways to maintain animal health, welfare and performance. Feed enzymes were one of the biggest breakthroughs in animal nutrition in recent years, allowing nutritionists to formulate cheaper diets while maintaining animal performance, reducing production costs and potential environmental pollution. Today, phytases and carbohydrases are widely accepted in poultry nutrition but, despite this, the way in which feed enzymes are applied to diets remains conservative. Historically, this has been based on a limited understanding of the level and nutritional influences of enzyme substrates and of the changes enzymes can bring about to animal metabolism and physiology. In recent times, our understanding in each of these areas has progressed, opening up new opportunities to exploit the full potential of feed enzyme application. This article will explore the application of phytase and xylanase to overcome the anti-nutritive effects associated with phytate and fibre respectively.


Anti-nutritive effects of phytate and phytase superdosing Phytate is known to be a potent anti-nutrient, impairing the utilisation of minerals and other nutrients such as amino acids and energy. Phytase application has evolved significantly in the past 7-8 years with the introduction of the practice of using high doses or “superdoses”


of phytase to move closer to full destruction of phytate (IP6) and its lower esters (IP5-IP1). Higher doses of phytases can also deliver animal performance


benefits through the full dephosphorylation of phytate to create inositol in-situ. Inositol is the backbone of the phytate molecule, and is reported to improve energy metabolism, helping animals utilise dietary energy more efficiently. In one broiler trial, it was estimated that one third of the feed conversion rate (FCR) benefits observed with phytase superdosing was caused by inositol provision (Figure 1). Phytase superdosing can be utilised to deliver improved animal


performance simply by topping up the feed with extra phytase without assuming any nutritional contribution. To achieve this, producers formulating diets with 500 FTU/kg of phytase while assuming the standard nutritional contribution from the enzyme should simply add more enzyme to target a final in-feed activity of 1,500-2,500 FTU/ kg. This can improve poultry and pig feed efficiency through higher phytate breakdown (usually a reduction of around 3-4 FCR points in FCR). This approach requires an increased feed cost up front and assumes that the extra nutrients released through phytate destruction are converted to more meat or improved animal efficiency. To build on the commercial benefits of superdosing, AB Vista


has conducted extensive research to further understand the quantity of amino acids, minerals and energy that can be spared by the use of higher dosages of Quantum Blue phytase, and also how dietary phytate level could impact animals and enzyme response. The usual approach is to conduct this research through digestibility assays; however, AB Vista decided to take a different approach, instead running dose response trials with the nutritionally important amino acids, providing a more realistic picture of the impact of phytase


Figure 1: Inositol release partially explains phytase superdosing benefit


Table 1: Quantum Blue sparing effect on amino acids Response variable


BW gain, d0-42 FCR, d0-42


Carcass weight, d42 Breast weight, d42 BW gain, d0-21 FCR, d0-21


AID amino acid, d21 Average


PAGE 34 NOVEMBER/DECEMBER 2018 FEED COMPOUNDER


% of M+C spared


15.9 9.9 * *


17.2 14


16.3 14.70%


% of Lys spared†


8


11.4 13.6 *


15.9 19.2 8.1


12.70%


% of Thr spared†


12.5 2.9 * *


4 2 *


5.40%


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