Effect of exogenous enzymes on broiler performance
T. I. Mohamed
Endogenous enzymes
Poultry produced at significant levels ----> Amylase, isomaltase,
maltase, chymotrypsin, pepsin, trypsin and lipase
GIT mircoflora (lower GIT) ---> phytase & fiber hydrolyzing enzymes
Amylase secretion by salivary glands ---> very limited.
Amylase activity in the crop, glandular stomach and gizzard --->
very low limited
Amylase from the duodenum, jejunum to ileum due to a secretion
by the pancreas, intestinal secretions increase
Lipase
The main source ---> pancreas
Bile ---> involved in activation of pancreatic lipase
1- Age
- GIT of young broilers is not fully developed to digest starch –
protein and lipid
Young birds are more limited in types and amounts of enzymes necessary
to utilize a high carbohydrate and vegetable protein diet ----> affecting
nutrient digestibility and the overall performance
-Lower amylase activity in young chicks compared to older birds
---> digestibility of starch in different ingredients is lower in 21-day-
old broilers than in adult.
-Low proteolytic activity (15% lower in 1W chicks compared to 4 w).
- Low lipase activity
Factors affecting Endogenous enzyme activity
2- Enzyme inhibitors (High levels of phytate, fibre (cellulose)
and less digestible protein) in most cereal & leguminous
grains ---> negative effect on digestion of starch – protein –
lipid ---> significantly decrease conc. of amylase, sucrase,
Na+K+-ATPase in the jejunum by 10 to 22%,
High levels of Enzyme inhibitors --> increased pepsin,
chymotrypsin & trypsin production in poultry --> endogenous
amino acid losses
antinutrients as soluble NSPs, ---> increase digesta viscosity
---> decrease fat digestibility and increase coccidiosis.
Corn-Soy Diets and Digestibility
The corn-soy diets became widely fed at the time of serving as reference feed in terms of nutrient composition and digestibility.
The digestibility of energy in corn is relatively high ---> over 90 %
The digestibility of energy in soybean (both meal and full-fat)
energy ---> 70 - 75 %.
This limitation in soya energy yield (and other plant protein sources) associated to the presence of anti-nutritional factors ---> reduced enzyme activity at the animal level.
Thus, enzyme supplementation can improve the energy and nutrient utilization of corn-soy diets
2 major feed enzyme groups:
amylases and proteases ---> produced at significant levels by
poultry.
Other feed enzyme as fibre-hydrolyzing enzymes (NSPases)
and phytase – are not directly produced by the bird
amylase protease increased daily gain and feed intake & FCR
---> due to improve starch & protein digestibility & reduction in
endogenous losses through reduction in endogenous protease
and amylase production.
Relationship between endogenous and feed enzymes
Exogenous enzymes
Definition Enzymes are non living substances,
Biological catalyst,
Act on specific substrate,
Used as feed supplements
Types
- Proteases
- Lipases
- Phytases
- Non Starch Polysaccharidases as xylanases and beta-glucanases ---> widely used in wheat and barley-based and corn-soybean diets
phytase, amylase, and protease enzymes used in various types of poultry diets
Characteristics of ideal enzymes
Specificity of action
Heat stability during the feed preparations
Less expensive
and more safety
Reducing the effects of anti nutritional factors
Objectives of exogenous enz supplementation
Improve fiber digestion.
Improves protein and starch availability.
Improve Digestibility & nutrient utilization.
Reduce intestinal viscosity.
Reduce pathogenic microflora and the improve health.
Reduce feed cost and nutrient excretion.
Improves production Efficiency & decrease production cost
Reducing the need for amino acids and fat supplements
enz supplementation ---> improved nutrient utilization
from diet ---> reduce vegetable oils (high cost) inclusion in
diet ---> significant decrease in input costs
Objective
In addition to viscosity reduction, an increase in the productive value with enzyme supplementation can be achieved by:
Hydrolysis of certain types of carbohydrate-protein linkages and ---> improved availability of amino acids.
Release of available phosphorus from phytate hydrolysis.
Hydrolysis of “resistant starch” and improved energy utilization.
• hydrolyzing enzyme inhibitors found in feed
Depolymerization of cell wall polysaccharides ---> elimination of their nutrient encapsulating effect ---> more effective energy and amino acid utilization.
Release of readily available energy from oligosaccharide hydrolysis.
Decrease environmental pollution by reduction of nitrogen and phosphorus excretion by animals
Application of exogenous enzymes
enzymes that enhance the digestive ability of the animal
newly hatched birds with immature digestive systems in which some enzymes (α-amylase, sucrase, maltase, protease, lipase, etc.) are not produced in sufficient quantities which may result in incomplete utilization of dietary nutrients.
enzymes that are not produced by animal
for hydrolysis of a variety of indigestible components of poultry feeds. Dietary fiber components (i.e., non-starch polysaccharides, glycoproteins), phytate, oligosaccharides or resistant starch undergo a limited conversion to substrates available for absorption and could be degradable by exogenous enzymes of microbial or fungal origin ---> improving the nutritive value of feedstuffs.
Efficacy of Exogenous Enzymes
Efficacy of Exogenous Enzymes depended on
enzymes are specific (substrate)
maintain a given enzyme : substrate ratio
effective when several conditions like temperature, humidity and pH
Formulated diets should be economic (below the recommended nutrient requirements)
Also, Efficacy of Exogenous Enzymes depended on
1- feed ingredient costs
2- enzyme costs
3- dietary specifications
4- bird age
5- ingredient quality
There is a synergistic effect for some enzyme activities
combined phytase and xylanase ---> improve FCR 5.09%
xylanase or phytase alone ---> improve FCR 2.66% and 2.28%,
respectively
•phytase, amylase, protease and xylanase ---> improve FCR 10.4%
of broilers fed a corn-based diet
•phytase only or a mixture of amylase, protease and xylanase only
---> improve FCR a 7.3% and 8.4%, respectively
ACTION OF ENZYMES Phytases :Liberate Inorganic Phosphate
From Bound Phytate
P P
P
P P
P P
P
P
P
+ P Phytase
Non Starch Polysaccharides
Cereals & byproducts:
Xylan
Beta glucan
Cellulose
Starch
Lipids & Phytate
Legumes & meals
Pectins
Alphagalactosides
Cellulose
Protein
Lipids & Phytate
NSP’s based on Solubility
SOLUBLE NSP’s Responsible for increase in viscosity of gut.
Slow down the intestinal transit time
Proliferation of fermentative organisms
Adverse Effect
High gut viscosity decreases the rate of diffusion of nutrients.
enzymes and Functions
Enzyme Substrate Effects
Cellulase cellulose Degradation of cellulose
β-Glucanase
β-glucans Reduction of intestinal digest viscosity
Pectinase Pectins Reduction of intestinal digest viscosity
Xylanase xylans Reduction of intestinal digest viscosity
Galactisidases Galactisideses Reduction of intestinal digest viscosity
Phytase Phytic acid Reduction of intestinal digest viscosity and degradation of phytate
Effect of pentosanase on broiler chicks fed a wheat-based diet
parameter control Pentosanase
(1000XU/ kg SED P Value
Daily gain,g 34a 36.6 b 0.475 0.001
Daily intake,g 54a 54.8 b 0.641 0.05
Feed efficiency
0.634 a 0.657 b 0.003 0.001
Effect of a soy-specific enzyme cocktail containing protease and cellulase on broilers fed a wheat, soydiet
parameter control Enzyme supplemented
Weight gain 15 days (g) 549 569
Weight gain 29 days (g) 1463 1500
FCR 15 days (g ) 1.617 a 1.559 b
FCR 29 days (g ) 1.63 a 1.707 b
Effect of exogenous enzyme on fat digestibility of chicks
Treatment Fat digestibility
Control diet (corn soy diet) 81 b
HOASS 75.2 d
HOASS + Lipase (L ) 76.8 c
HOASS + phosphoLipase (P )
79.5 b
HOASS +L+P 80.2 b
HOASS=high oleic acid sunflower seed 250g/kg
Effect of xylanase on fat digestibility and intestinal viscosity
parameter Soy oil Soy oil + Xylanase
Weight 21 days (g ) 681 a 761 b
FCR 0-21 days 1.392 ab 1.266 b
Jejunal viscosity (mpa,s) 438 32
CF digestibility 82.3 a 87.3 b
Effect of beta-glucanase on broiler performance fed a barley-based diet (to 39 days). Diet contains 50%barley containing
4.3% beta-glucan
Enz level
u/ kg feed
Feed intake
g
Body weight, g
FCR
0 96.5 a 2163 a 1.742 a
100 95 ab 2193 ab 1.692 b
200 95.3 ab 2215 b 1.678 b
400 93.2 b 2160 a 1.685 a
Conclusion
Exogenous enzyme supplementation
improve digestibility�
Flexibilization of feed formulation�
Increase availably of low quality ingredient
�Reduced production cost
Thank you