Digital Re-print - January | February 2013

Feed enzymes in animal nutrition

www.gfmt.co.uk

Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872

Enzyme technology is an integral tool for the brewing, baking and textile industries. In agriculture

there is great potential for enzymes too but this is yet to be fully exploited. However, animal nutrition is one area in which the use of feed enzymes is becoming increasingly important.

There are three driving factors in animal production that are leading to the develop-ment and adoption of feed enzyme technol-ogy. First, the world’s growing population has meant global demand for food and in particular meat and meat products have increased substantially. In addition, produc-ers are also continually looking for novel methods of increasing their efficiency and productivity and the cost and availability of raw materials for animal feed is the second factor continuing price rises are a major con-straint to meeting demand. The third factor is concern over the environmental fragility of the planet and the pressure on agricultural industries to reduce their reliance on vital resources.

Major ingredients in monogastric feeds

The major ingredients used in most monogastric feeds are of vegetable origin including ground cereals such as maize, wheat and barley or vegetable by-products such as wheat middlings and rice bran. It also includes processed protein ingredients such as soybean, or rapeseed extractions and unprocessed materials such as peas or beans. All these materials have a complex structure of carbohydrates, protein and oil and the carbohydrates are further described as sugars, starch and non-starch polysac-charides (NSP).

Digging deeper, the NSP components

can be further divided into beta-glucans, celluloses and pentosans. Indeed, many dif-ferent types of enzymes are secreted within the digestive tract but there are cases where the enzymes that are necessary for complete digestion are not produced by the animal or are only present at very low levels. In monogastric animals it is the enzymes that are required to breakdown the NSP fraction of the diet that are missing.

Increasing feed value through enzymes

The NSP fraction of barley and oats con-tains beta-glucans which can hold significant amounts of water causing high gut viscosity. Young pigs and poultry lack the required beta-glucanase enzyme to break the link-ages of the molecule and this is a problem because it has an anti-nutritional effect by blocking the absorption of nutrients. Increased viscosity also reduces the rate of passage thus lowering feed intake with the end result being reduced growth rates, feed conversion and the appar-ent metabolisable energy of the diet. Increased viscosity additionally results in wet litter which in poultry leads to conditions such as necrotic enteritis, hock burns and breast blisters.

Similarly in wheat, a common cereal choice in temperate climates, the NSP fraction contains a high level of arabinoxylans. Xylanase is the enzyme that pigs and poultry require in order to break these compounds down but they are also deficient in them and, it was not until the development of beta-glucanase and xylanase enzymes for animal feed in the 1980s, that this

issue was addressed. Now these enzymes are commonplace, certainly in Europe, where poultry diets are principally com-posed of wheat and barley.

Recent enzyme developmentsMore recently, positive effects in animal

performance have also been noted with ‘non-viscous’ cereals such as maize and sor-ghum (Choct, 2006). The digestive system in pigs differs slightly from poultry and the issue of increased viscosity from wheat and barley is not a problem in these species. The addition of feed enzymes in pig diets has also demonstrated positive effects (Dierick and Decuypere, 1994) and it is recognised that beta-glucanases and xylanases are able to degrade plant cell wall which leads to a release of nutrients from grain endosperm

Table 1: Optimal temperature and pH properties from some fungal endoxylanases (adapted from Corral and Villanseñor-Ortega, 2006)

SOURCEOptimum

Temperature (Oc)

Optimum Ph

Apergillus kawachiiABC

605550

5.54.52.0

Aspergillus nigerXynA I

XyanA II50

45-505.04.5

Penicillium CapsulatumXynAXynB

4848

4.04.0

Talaromyces emersoniiXyn IXyn IIXynIII

Xyn IVXyn V

7577737780

4.74.34.24.34.2

by Elizabeth Norton, nutritionist, Anpario plc, United Kingdom

Grain&feed millinG technoloGy18 | January - february 2013

FEATURE

Enzyme technology is an integral tool for the brewing, baking and textile industries. In agriculture

there is great potential for enzymes too but this is yet to be fully exploited. However, animal nutrition is one area in which the use of feed enzymes is becoming increasingly important.

There are three driving factors in animal production that are leading to the develop-ment and adoption of feed enzyme technol-ogy. First, the world’s growing population has meant global demand for food and in particular meat and meat products have increased substantially. In addition, produc-ers are also continually looking for novel methods of increasing their efficiency and productivity and the cost and availability of raw materials for animal feed is the second factor continuing price rises are a major con-straint to meeting demand. The third factor is concern over the environmental fragility of the planet and the pressure on agricultural industries to reduce their reliance on vital resources.

Major ingredients in monogastric feeds

The major ingredients used in most monogastric feeds are of vegetable origin including ground cereals such as maize, wheat and barley or vegetable by-products such as wheat middlings and rice bran. It also includes processed protein ingredients such as soybean, or rapeseed extractions and unprocessed materials such as peas or beans. All these materials have a complex structure of carbohydrates, protein and oil and the carbohydrates are further described as sugars, starch and non-starch polysac-charides (NSP).

Digging deeper, the NSP components

can be further divided into beta-glucans, celluloses and pentosans. Indeed, many dif-ferent types of enzymes are secreted within the digestive tract but there are cases where the enzymes that are necessary for complete digestion are not produced by the animal or are only present at very low levels. In monogastric animals it is the enzymes that are required to breakdown the NSP fraction of the diet that are missing.

Increasing feed value through enzymes

The NSP fraction of barley and oats con-tains beta-glucans which can hold significant amounts of water causing high gut viscosity. Young pigs and poultry lack the required beta-glucanase enzyme to break the link-ages of the molecule and this is a problem because it has an anti-nutritional effect by blocking the absorption of nutrients. Increased viscosity also reduces the rate of passage thus lowering feed intake with the end result being reduced growth rates, feed conversion and the appar-ent metabolisable energy of the diet. Increased viscosity additionally results in wet litter which in poultry leads to conditions such as necrotic enteritis, hock burns and breast blisters.

Similarly in wheat, a common cereal choice in temperate climates, the NSP fraction contains a high level of arabinoxylans. Xylanase is the enzyme that pigs and poultry require in order to break these compounds down but they are also deficient in them and, it was not until the development of beta-glucanase and xylanase enzymes for animal feed in the 1980s, that this

issue was addressed. Now these enzymes are commonplace, certainly in Europe, where poultry diets are principally com-posed of wheat and barley.

Recent enzyme developmentsMore recently, positive effects in animal

performance have also been noted with ‘non-viscous’ cereals such as maize and sor-ghum (Choct, 2006). The digestive system in pigs differs slightly from poultry and the issue of increased viscosity from wheat and barley is not a problem in these species. The addition of feed enzymes in pig diets has also demonstrated positive effects (Dierick and Decuypere, 1994) and it is recognised that beta-glucanases and xylanases are able to degrade plant cell wall which leads to a release of nutrients from grain endosperm

Table 1: Optimal temperature and pH properties from some fungal endoxylanases (adapted from Corral and Villanseñor-Ortega, 2006)

SOURCEOptimum

Temperature (Oc)

Optimum Ph

Apergillus kawachiiABC

605550

5.54.52.0

Aspergillus nigerXynA I

XyanA II50

45-505.04.5

Penicillium CapsulatumXynAXynB

4848

4.04.0

Talaromyces emersoniiXyn IXyn IIXynIII

Xyn IVXyn V

7577737780

4.74.34.24.34.2

by Elizabeth Norton, nutritionist, Anpario plc, United Kingdom

Grain&feed millinG technoloGy18 | January - february 2013

FEATURE

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and the aleurone layer cells and therefore improves the energy value of the feed.

Reducing pathogenic bacteria in the colon

A third possible mechanism by which the nutritive value of feed is increased by feed enzymes is through the release of oligosac-charides (Choct and Cadogan, 2001). These can be formed during the degradation of storage and cell wall carbohydrates by sup-plemental enzymes and are able to resist further degradation by digestive enzymes and so able to reach the colon. Once in the colon these oligosaccharides are a nutri-ent source for beneficial bacteria such as Bifidobacterium and Lactobacillus spp which suppress the growth of pathogenic bacteria such as Salmonella, Clostridium, Campylobacter and Escherichia coli. It is well established that reducing pathogenic bacteria in the colon improves weight gain and the feed conver-sion ratio in pigs and poultry.

Cost saving feed formulationRegardless of the mechanism by which

the energy value of feed is increased, the fact that it occurs is of significant importance for producers and nutritionists. This allows for greater flexibility when formulating diets meaning that alternative feed ingredients, which are traditionally of lower nutritive value, can be utilised in the formulation. This can result in significant savings in feed costs for producers where, for example, some of the wheat-based portion of the diet can be replaced with cheaper barley, providing a suitable blend beta-glucanase and xylanase enzymes are incorporated into the diet.

Phytase developmentThe 1990s saw the development of the

next enzyme of significant importance in ani-mal nutrition, phytase. Phosphorous is a very important and valuable mineral element in all species as it is crucial for bone development and metabolic processes.

In plants, the majority of phosphorous is stored in the form of phytate. Monogastrics are unable to utilise the phosphorous in phytate so it is a major source of an important nutrient that is normally wasted. Instead, producers have to supplement diets with inorganic phosphorous supplements although dependence on inorganic phos-phorous supplements is a challenge because global reserves of rock phosphate are not renewable and the price has escalated. Furthermore, producers have a tendency to over-supplement with inorganic phos-phorous with the result that most of it is excreted by the animal and becomes a major environmental pollutant.

Phytase benefitsWhen the development of phytase

enzymes began it was largely to reduce the requirements for inorganic phospho-rous thus saving money for producers and

reducing the envi-ronmental impact. However, it has become apparent that further nutri-tional benefits are achieved because phytate has the capacity to bind other important minerals such as calcium, zinc, manganese, iron and copper thus reducing their bioavailability in the digestive tract.

Additional research has also revealed that the inclusion of phytase can improve both ileal amino acid digestibility and dietary avail-able metabolisable energy (Ravindran et al 2001). Phytate is therefore con-sidered as both an indigestible nutri-ent and an anti-nutrient and inter-estingly, in the last decade, research has demonstrated that administering unconvention-ally high doses or by ‘superdosing’ phytase in diets that animal perform-ance can be sub-stantially improved (Cowieson et al 2011).

Challenges associated with enzymes use

One of the major challenges with the cur-rent use of feed enzymes is that producers face dif-ficult decisions on which varieties to use and at what inclusion rates. Aside from the diet formulation and the ingredi-ents used, there are a number of factors that can affect the efficacy of feed enzymes.

Grain&feed millinG technoloGy January - february 2013 | 19

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New for 2014 Now including the first ASEAN Feed Summit

Specialist conferences The exhibition will be supportedby its own specialist conferences.They will include: The FIAAP Conference 2014Petfood Forum Asia 2014Aquafeed Horizons Asia 2014The Thai Feed Conference 2014

Supported by The Thailand Convention and Exhibition Bureau

Co-located with VICTAM Asia 2014www.victam.com

Contact details For visitor, exhibition stand space and conference information please visit:www.fiaap.com

Asia’s foremost exhibition andconferences for the ingredientsand additives used in the production of animal feeds,aquafeeds and petfoods

FIAAP Asia 2014 is the only dedicated trade show and conference organised specifically for feed ingredients,additives and formulation within the dynamic and growing region of South and South East Asia.

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Performance, flexibility and stability

Bespoke systems My organisation, BS&B Safety Systems,

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• An electrical signal generated by the sensor activates control circuits typically used to operate an automatic water-extinguishing curtain. Sparks can be extinguished without stopping production.

• An automated shut down of the process can prevent the feed of combustible material.

• Alarm and control systems can be activated upon the detection of hot particles for other control devices such as diverter valves.The system detectors and control unit

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Grain&feed millinG technoloGy January - february 2013 | 11

FEATURE

FEATURE

and the aleurone layer cells and therefore improves the energy value of the feed.

Reducing pathogenic bacteria in the colon

A third possible mechanism by which the nutritive value of feed is increased by feed enzymes is through the release of oligosac-charides (Choct and Cadogan, 2001). These can be formed during the degradation of storage and cell wall carbohydrates by sup-plemental enzymes and are able to resist further degradation by digestive enzymes and so able to reach the colon. Once in the colon these oligosaccharides are a nutri-ent source for beneficial bacteria such as Bifidobacterium and Lactobacillus spp which suppress the growth of pathogenic bacteria such as Salmonella, Clostridium, Campylobacter and Escherichia coli. It is well established that reducing pathogenic bacteria in the colon improves weight gain and the feed conver-sion ratio in pigs and poultry.

Cost saving feed formulationRegardless of the mechanism by which

the energy value of feed is increased, the fact that it occurs is of significant importance for producers and nutritionists. This allows for greater flexibility when formulating diets meaning that alternative feed ingredients, which are traditionally of lower nutritive value, can be utilised in the formulation. This can result in significant savings in feed costs for producers where, for example, some of the wheat-based portion of the diet can be replaced with cheaper barley, providing a suitable blend beta-glucanase and xylanase enzymes are incorporated into the diet.

Phytase developmentThe 1990s saw the development of the

next enzyme of significant importance in ani-mal nutrition, phytase. Phosphorous is a very important and valuable mineral element in all species as it is crucial for bone development and metabolic processes.

In plants, the majority of phosphorous is stored in the form of phytate. Monogastrics are unable to utilise the phosphorous in phytate so it is a major source of an important nutrient that is normally wasted. Instead, producers have to supplement diets with inorganic phosphorous supplements although dependence on inorganic phos-phorous supplements is a challenge because global reserves of rock phosphate are not renewable and the price has escalated. Furthermore, producers have a tendency to over-supplement with inorganic phos-phorous with the result that most of it is excreted by the animal and becomes a major environmental pollutant.

Phytase benefitsWhen the development of phytase

enzymes began it was largely to reduce the requirements for inorganic phospho-rous thus saving money for producers and

reducing the envi-ronmental impact. However, it has become apparent that further nutri-tional benefits are achieved because phytate has the capacity to bind other important minerals such as calcium, zinc, manganese, iron and copper thus reducing their bioavailability in the digestive tract.

Additional research has also revealed that the inclusion of phytase can improve both ileal amino acid digestibility and dietary avail-able metabolisable energy (Ravindran et al 2001). Phytate is therefore con-sidered as both an indigestible nutri-ent and an anti-nutrient and inter-estingly, in the last decade, research has demonstrated that administering unconvention-ally high doses or by ‘superdosing’ phytase in diets that animal perform-ance can be sub-stantially improved (Cowieson et al 2011).

Challenges associated with enzymes use

One of the major challenges with the cur-rent use of feed enzymes is that producers face dif-ficult decisions on which varieties to use and at what inclusion rates. Aside from the diet formulation and the ingredi-ents used, there are a number of factors that can affect the efficacy of feed enzymes.

Grain&feed millinG technoloGy January - february 2013 | 19

8 – 10 April 2014 . Bangkok International Trade & Exhibition Centre (BITEC), Bangkok, Thailand

New for 2014 Now including the first ASEAN Feed Summit

Specialist conferences The exhibition will be supportedby its own specialist conferences.They will include: The FIAAP Conference 2014Petfood Forum Asia 2014Aquafeed Horizons Asia 2014The Thai Feed Conference 2014

Supported by The Thailand Convention and Exhibition Bureau

Co-located with VICTAM Asia 2014www.victam.com

Contact details For visitor, exhibition stand space and conference information please visit:www.fiaap.com

Asia’s foremost exhibition andconferences for the ingredientsand additives used in the production of animal feeds,aquafeeds and petfoods

FIAAP Asia 2014 is the only dedicated trade show and conference organised specifically for feed ingredients,additives and formulation within the dynamic and growing region of South and South East Asia.

FIAAP:ad 5/2/13 10:37 Page 1

RAISING STANDARDS

Now with

MLA technology

Raise your standards of performance with Econase® XT and Mixer Liquid Application.

Looking for improved profitability in uncertain times?

Econase® XT Mixer Liquid Application technology optimises production and feed efficiency, offering you significant cost savings.

The only liquid NSP enzyme stable enough to add prior to pelleting.

• Improved FCR • Consistent in-feed homogeneity • Can reduce power consumption when pelleting

Econase® XT from AB Vista – the leaders in enzyme innovation.

Find out more: E: econasext@abvista.com T: +44 (0)1672 517664 W: abvista.com

Performance, flexibility and stability

Commercially enzymes are produced by sub-merged culture fermentation using micro-organisms grown on substrate. Individual enzymes which are produced by the same microorganisms can be completely different and even those produced by the same micro-organism, but on different substrates, may have different actions engendering their specificity. It is the optimal temperature and pH at which these enzymes are most active that is most affected by the different sources (Table 1).

This clearly has implications on how effec-tively enzymes will function in the digestive tract. Generally the digestive tract of monogastric species such as pigs and poultry is amenable to exogenous enzymes but the reasons for this can differ depending on the species. In pigs, for example, the stomach can store a large quantity of feed increasing the pH and the feed is also retained in the small intestine longer which is favourable for optimal exogenous enzyme activity. However, superior and more consistent results are often seen in poultry which may be due to the lower moisture content in poultry digesta (Svihus 2010) and also, certain ingredi-ents used in diets may affect the pH in the tract and the natural variations in nutritional value of cereal grains can render enzymes ineffective.

The current enzymes available have taken years to develop and have proven effi-cacy in pigs and poultry as demonstrated by numerous in vivo trials. Nonetheless, greater understanding of the sources of variation that contribute to mitigating or accentuating the effect of feed enzymes will enable nutritionists and producers to figure out optimal inclusions for specific enzymes in diet formulations.

Another area that has been a major focus of research is the development of types of enzyme that can withstand the extreme conditions during feed manufacture. Thermostability is of particular importance and this can be achieved through either genetic manipulation or protective coatings and these products are now widely available.

Enzymes and ruminantsResearch has also demonstrated that feed

enzymes can be very effective for improv-ing performance in ruminant species too, although there are many challenges that need to be addressed before they are made commercially available. The complexity of the rumen microbial ecosystem and the proc-ess of fibre digestion means that the mode of action of ruminant enzymes is not well understood. Further information regarding the synergy between feed enzyme additives and the rumen enzymes produced by the existing microflora is also needed. Some research has however found evidence of cooperation between the two but it has also been noted that feed enzymes compete with fibrolytic bacteria in the rumen for available binding sites on feed (Morgavi et al., 2004).

Enzymes and aquaculture Aquaculture is another industry that

could benefit from the application of feed

enzymes. It continues to be the fastest growing animal food-producing sector and is set to outpace human population growth. Omnivorous fish species such as tilapia and carp can utilise plant-based diets and are of increasing importance, therefore fibre-degrading enzymes such as xylanase and beta-glucanase may be beneficial.

The reliance of fishmeal for carnivorous fish species is having a negative impact on the environment and is also highly expensive, so identifying alternative protein sources for these species is of vital importance. At present very little research on feed enzymes in aqua-culture has been documented although some initial studies have reported improvements in phosphorous availability in diets through the addition of phytase in fish feeds (Jackson et al, 1996; Hughes and Soares, 1998) and the development of enzymes that can withstand processing pressure during fish feed manufac-ture is clearly an important factor too.

Enzymes and energy productionFinally, the need to reduce reliance on

fossil fuels and utilise renewable fuel sources such as bioethanol presents further opportu-nities for the use of feed enzymes in animal nutrition. Production of ethanol by the enzy-matic breakdown of starch and sugars, fol-lowed by yeast-driven fermentation creates a number of waste-products that could be utilised as animal feed ingredients. The main waste-product available is distillers’ dried grains with solubles (DDGS). There is some current debate over the nutritional value of DDGS as this can be affected by the initial grain used for the bioethanol production. Arabinoxlans and phytate content has also reported to be higher in DDGS than those found in feedstock cereals grains (Zijlstra and Beltranena, 2009) and the quality of protein and amino acid availability in DDGS is also questionable (Péron and Partridge, 2010). However, due to the apparent availability of this as a feed source used in conjunction with exogenous enzymes, DDGS has poten-tial and research in this area is increasing.

The growing importance of enzymes

In conclusion, feed enzymes are an increas-ingly important tool in animal nutrition. This article has attempted to demonstrate how enzymes can alleviate pressures relating to the increase in demand for global meat produc-tion, constraints on raw material availability and calls for reducing the environmental impact of animal production. The application of fibre-degrading and phytase enzymes in pig and poultry diets is widely available and has proven beneficial effects. Feed enzyme manufacturers continue to improve existing enzymes building on the knowledge that has been developed over the last two decades. Developing varieties for other species such as cattle and fish and new feed ingredients like DDGS offer further potential for the use of feed enzymes in animal nutrition in the years ahead.

ReferencesChoct, M. (2006) Enzymes for the feed industry:

past, present and future. World’s PoultryScience Journal 62, 5–16.Choct, M. and Cadogan, D.J. (2001) How effective

are supplemental enzymes in pig diets? In:Cranwell, P.D. (ed.) Manipulating Pig Production VIII.

University of South Australia,Adelaide, Australia, pp. 240–247.Corral, O.L. and Villanseñor-Ortega, F. 2006

Xylanases. In: Guevara-González, R.G. and Torres-Pacheco, eds. Advances in Agricultural and Food Biotechnology Research Signpost 305-322.

Cowieson, A.J., Wilcock, P. and Bedford, M.R. (2011) Super-dosing effects of phytase in poultry and other monogastrics. World Poultry Science 67, 225- 235

Dierick, N.A. and Decuypere, J.A. (1994) Enzymes and growth in pigs. In: Cole, D.J.S.,

Wiseman, J. and Varley, M.J. (eds) Principles of Pig Science. Nottingham University

Press, Nottingham, UK, pp. 169–195.Hughes, K.P. and Soares, Jr (1998) Efficacy of phytase

on phosphorous utilization in practical diets fed to striped bass Morone saxatilis. Aquaculture Nutrition, 4, 133-140.

Jackson, L.S., Li, M.H. and Robinson, E.H. 1996. Use of microbial phytase in Channel Catfish Ictalurus punctatus diets to improve utilization of phytate phosphorous. Journal of World Aquaculture 27, 3, 309-313.

Morgavi, D.P., Beauchemin, K.A., Nsereko, V.L., Rode, L.M., McAllister, T.A. and Wang, Y.

(2004) Trichoderma enzymes promote Fibrobacter succinogenes S85 adhesion to, and

degradation of, complex substrates but not pure cellulose. Journal of the Science of Food

and Agriculture 84, 1083–1090.Péron, A. and Partridge, P.P., 2010. Other enzyme

applications relevant to the animal feed industry In: Bedford, M.R. and Partridge, G.G eds. Enzymes in farm animal nutrition. CAB International, 231-248.

Ravindran, V., Selle, P.H., Ravindran, G., Morel, P.C.H., Kies, A.K. and Bryden, W.L. (2001)

Microbial phytase improves performance, apparent metabolizable energy and ileal amino

acid digestibility of broilers fed a lysine-defi cient diet. Poultry Science 80, 338–344.

Svihus, B. 2010 Effect of digestive tract conditions, feed processing and ingredients on response to NSP enzymes. In: Bedford, M.R. and Partridge, G.G eds. Enzymes in farm animal nutrition. CAB International, 129-159.

Zijlstra, R.T. and Beltranena, E. (2009) Variability of quality in biofuel co-products. In:

Garnsworthy, P.C. and Wiseman, J. (eds) Recent Advances in Animal Nutrition

2008. Nottingham University Press, Nottingham, UK, pp. 313–326

About the author:Elizabeth Norton is a nutritionist at Anpario

providing technical support across the com-pany’s brands. She is responsible for providing nutritional advice and diet formulations for cus-tomers. Elizabeth has a First Class BSc (Hons) Animal Science at the University of Plymouth.

More InforMatIon:Website: www.anpario.com

Grain&feed millinG technoloGy20 | January - february 2013

FEATURE

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A subscription magazine for the global flour & feed milling industries - first published in 1891INCORPORATING PORTS, DISTRIBUTION AND FORMULATION

In this issue:

• Efficient barge unloading technology

• Feed enzymes in animal nutrition

• Controlling the explosion risks within hammer mills

• Use of computer programming in animal diet formulation

• Recycling surplus factory food into quality animal feeds

Janu

ary

- Feb

ruar

y 20

13

first published in 1891

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