Why Does Enzyme Thermostability Matter?
Published: June 19, 2017
By: Basheer Nusairat, Ph.D. Animal Nutritionist, BRI.
The Impact of Feed Pelleting on Enzyme Thermostability
In animal feed manufacturing, the process of pelleting is used to convert mash feed into compressed pellets. Pelleting provides several advantages, such as ease of handling, reduction of dust and waste and standard composition. The use of pelleted feed is also known to improve the feed conversion ratio (FCR) due to better digestibility and absorption of nutrients by the animal. During the conditioning phase of pelleting, the feed is subjected to steam, which helps reduce or eliminate pathogens such as Salmonella that could be present in the feed.
Conditioning time can vary from a few seconds up to several minutes depending on the type and formulation of the feed. The temperature during conditioning typically ranges from 70°C to 100°C. After conditioning, the feed is extruded through a pelleting die, which for a short time raises the temperature of the feed incrementally due to friction. Because enzymes are proteins, they are susceptible to being denatured by heat and pressure. Denaturing essentially alters the structure of the enzyme, resulting in decreased activity levels and decreased efficacy of the enzyme.
Ways to Improve Enzyme Thermostability
Maintaining an acceptable level of enzyme activity post-pelleting can be challenging. To improve thermo-tolerance, multiple solutions have been developed.
- Post-pellet liquid application can be used to protect the enzyme from denaturation caused by heat treatment. This solution is relatively complex and expensive because it requires the purchase and installation of specialized equipment, space in which to store the liquid enzyme and careful calculation of the amount of enzyme to apply.
- Application of a protective coating to the enzyme before pelleting is another alternative that can protect the enzyme from exposure to high levels of heat and moisture during feed manufacturing. This approach may reduce the efficacy of the enzyme because the coating may not fully dissolve in the upper digestive tract of the animal. It is difficult to achieve a coating design that can withstand the high heat and moisture content of the pelleting process, but subsequently, dissolve in the lower temperature and higher moisture conditions of the animal’s gut.
- Intrinsically thermostable enzymes are considered by many enzyme manufacturers to be the optimum solution. These enzymes are developed from thermophilic and hyper-thermophilic organisms and are known to have unique structure and function properties of high thermostability at temperatures above 85°C. Intrinsically thermostable enzymes can be added to animal feed without special coating and still retain high activity levels post-pelleting.
Intrinsically thermostable enzymes are often a preferred option for both feed mills and animal producers because they are available in dry form. Dry-form enzymes work well with standard equipment as they can be hand-added in a premix to pre-pelleted feed or can be used with a micro-ingredient system. Enzymes in dry form have a longer shelf life than those in liquid form and can be easily transported, distributed, stored and handled. Most importantly, the activity level of intrinsically thermostable enzymes is not lost due to high conditioning and pelleting temperatures.
Blog post originally published in BioResource International website (http://briworldwide.com).
References
Amerah, A. M., C. Gilbert, P. H. Simmins, and V. Ravindran. 2011. Influence of feed processing on the efficacy of exogenous enzymes in broiler diets. World’s Poultry Science Journal 67: 29 – 46.
Ravindran, V., and J-H Son. 2011. Feed enzyme technology: Present status and future developments. Recent Patents on Food, Nutrition & Agriculture 3: 102-109.
Vieille, C., and G. J. Zeikus. 2001. Hyperthermophilic enzymes: sources, uses, and molecular mechanisms for thermostability. Microbiology and Molecular Biology Reviews 65: 1–43.
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31 de diciembre de 2020
Thermostability of enzyme during pelleting is always a big question. It is very difficult to asses the effect of enzymes. Some enzyme producers claim it is intrinsically thermostable coated and so on. In true sense, post pelleting application is right method of enzyme application although we require sophisticated applicators. But still the efficacy of enzyme varies with the composition of diet, substrate present, enzyme concentration and favorable conditions like pH and temperature. Instead, we should develop a technology for in vitro application of enzymes to different feed ingredients based on their substrate analysis. This will be more economical and will serve the purpose of enzyme application to some extent although it looks to be more challenging today.
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Shahzad Feeds Mill
22 de mayo de 2019
how to calculate the enzyme dose according to substrate. please help me ?
rahatmobeen.533@gmail.com
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17 de julio de 2017
Who makes the thermostable enzymes and what is used to determine the correct amount to result in optimum food digestion and absorption?
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