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Animal Health

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Functional Additives
Monday, July 26, 2004 12:00:00 AM
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Versatility Takes Enzymes Beyond Simple Blending

YG Liu, Adisseo Asia Pacific,

Singapore and PA Geraert, Adisseo, France



Until recently, "versatility" and enzymes had little in common. Through a great deal of internal and external research,  Adisseo has identified that a number of enzymes in less dominant concentrations than the common xylanases and ß-glucanases can significantly improve the enzymatic activity against a wide range of grains and protein sources.




Given the complexity and variability of raw materials in animal feed, it is impossible to accurately predict the optimal enzyme combinations that should be used in feeds. An alternative approach is to rely on substrate sources in the fermentation process that represent the target materials in feed, in doing so the organism is forced to produce a range of enzymes to proliferate in a highly competitive environment.


A non-GMO microorganism Penicillium funiculosum, developed by Adisseo, is able to produce several xylanases, ß-glucanases and cellulases in association with other secondary or ancillary activities. All these activities are secreted during the same fermentation process. This natural combination of enzymes appears to be fully necessary to produce the optimal degradation of a broad range of non-digestible components present in feedstuffs. The enzyme activity profile (Rovabio Excel) is listed in Table 1.



Ancillary activities


Some of the secondary or ancillary enzyme activities that occur to assist in hydrolyses of NSP substrates. For example, in the group of xylanases, there are four ancillary activites that can support in degrading the linear ß- 1-4 xylan to xylose. The primary enzyme requirement is endo-xylanase, which is then assisted by ß-xylosidase that releases xylose from xylo-oligosaccharides. ß-arabinosidase then releases arabinose from branched xylan thus exposing the xylan 'backbone' to subsequent cleavages. Feruloyl esterase similarly assists by releasing xylan from the lignified cell wall core.


The enzyme system responsible for the degradation of cellulose includes: endo-1,4-ß-glucanase which degrades linear ß-1,4-glucans; cellobiohydrolase releases cellobiose from cellulose and oligosaccharides; ß-glucosidase releases glucose from oligosaccharides.


Ancillary enzymes may either de-branch the main backbones or act in concert with a variety of poorly understood factors that assist enzyme binding to their respective substrates, which is critical for the degradation of the intact substrates. This feature does not exist in those blended enzymes from GMO origins.


Efficacy of "one product for all"


In Adisseo, the responses of the enzyme Rovabio Excel were determined internally, with a focus on the magnitudes of ME improvements across different diet types and animal species. The digestibility tests procedures strictly follows the European reference method. For instance, broilers ME tests employ 19 to 22 day old birds, 12 replicates per dietary treatment, and total excreta collection. Piglet digestion trials also used 12 replicated per dietary treatment. Table 2 shows an example of the typical responses achieved with the Rovabio Excel enzyme product across diet type and species. There are a number of studies in Table 2 conducted in Asia and on corn and soybean meal diets. For instance, the meat-duck study by Nanjing Agricultural University in China consisted of 10 replicates for each dietary treatment and the test diets contained high levels of by-products such as cottonseed meal, peanut meal, rapeseed meal and wheat bran. The study found an ME increase of 319 kcal/kg, following Rovabio addition, indicating effective interactions between anti-nutritional factors and the versatile enzyme. The pig grower results on corn/SBM diets were obtained from a test in Thailand, in which the control diet contained an enzyme product. The results in Table 2 clearly demonstrate this versatile product has a positive response across wheat, barley and corn based diets; and for broilers, layers, turkeys, meat duck and pigs. For poultry, the ME improvement was 65-80 kcal/kg in corn and soybean meal diets. For piglets, the energy uplifts averaged DE 65 kcal/kg. In addition, there was about 3% increase in the digestibility of essential amino acids.





Synergy with in-feed antibiotics?


Among numerous controlled feeding studies conducted across diet types animal species and locations, Table 3 presents a typical pattern of Rovabio enzyme responses of growth performance from two broiler genetics, Ross x Hubbard (light breed) and Ross x Cobb (heavy breed) fed corn/SBM with and without in-feed antibiotics (Bacitracine Methylene Disalicylate, BMD and Tylosin phosphate). The trial employed 1,600 birds of each breed, 8 replicates/treatment with 50 birds/pen, diets were typical US corn and soybean meal formulations with four growth phases. The Rovabio enzyme was sprayed onto feed pellets at dosage 200 ml/t. The study was conducted by Virginia Scientific Research Inc. during late 2002. The highlight of the results is as below:

  • Rovabio enzyme responses were similar to those of in-feed antibiotics, 9-10% improvements in weight gain and  feed conversion (P<0.05) for both breeds 
  • A combination of Rovabio enzyme and AGP further enhanced performance in Ross x Hubbard, by 3-5% 
  • Rovabio enzyme, AGP and their combination tended to increase the yields of carcass and breast meat by 0.5-1 percentage units (P>0.05) 
  • Similar to that of AGP, the Rovabio enzyme response patterns suggested more benefits gained during the late growth phases. At the end of week 3, the light breed (Ross x Hubbard) showed statistical response in weight gain and feed conversion (P<0.05). The heavy breed (Ross x Cobb) displayed statistical improvements only at the end of growth (weeks 6 and 7)




For wheat/SBM diets, on the other hand Rovabio Excel obtained better responses than in-feed AGP(Virginiamycin) as shown by a recent study by IRTA in Spain (Table 4.) The addition of Rovabio reduced feed intake, improved feed conversion and weight gain, but there were no signs of synergies between these 2 additives. This may because feeding worn or wheat diets induced distinct different gut microflora.





In summary


In contrast to blended enzymes which are designated as being "diet specific" and "animal specific", Adisseo's Rovabio Excel is a versatile enzyme product, produced from a specific microorganism of natural selection (non-GMO), by a single fermentation. It offers 5 groups and 17 activities that seem to match well with complex non-starch polysaccharides (NSPs) across diets and animal species. On average it improves AME 65 kcal/kg for boilers and layers fed on corn and soybean meal diets, 85 kcal/kg for wheat-based diets, 140 kcal/kg for barley-based diets, and DE 65kcal/kg for pig diets. It also works well when used with in-feed antibiotics. This "one product for all" enzymes brings a great deal of convenience and simplicity to feed formulation, production and inventory management.


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