Ureatic activity and protein solubility in KOH of soybean meal samples obtained in poultry feed mills

Published on: 06/03/2020
Author/s : Mihayr Morais Jardim 1, Emmanuel Arnhold 2, Fabyola Barros de Carvalho 3, Roberto de Moraes Jardim Filho 4, Jose Henrique Stringhini 5. / 1 Nutrial Insumos Agropecuários; 2 Departamento de Zootecnia, EVZ/UFG, Brazil; 3 Departamento de Zootecnia, EVZ/UFG, Brazil; 4 São Salvador Alimentos; 5 Departamento de Zootecnia, EVZ/UFG; CNPq, Researcher, Brazil.

INTRODUCTIONThe use of soybean meal in poultry diets can be tested for antinutritional factors, which is easily identified with ureatic activity and protein solubility in KOH analysis. This research aimed to evaluate soybean meal quality measured by ureatic activity and KOH solubility in poultry feed mills.MATERIAL AND METHODSFor this analysis, 283 samples were obtained from a broiler feed mill lo...

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June 3, 2020

Soya processing under toasting and over toasting can be related to koh solubility. How the uretic activities good range for soya poultry feed.

June 3, 2020

Dear Dr. Stringhini et al., in my assessment your data on soybean meal quality are very interesting. Based on our experience, and considering also several reports in the scientific literature, the range of adequacy for KOH protein solubility in soybean meal is in the range of 80-85%. Your data based on the analysis of 283 samples from the commercial reality show that 52.64% of the samples or 189 out of 283 analyzed are exactly in the range 80-85%. On the other hand, 68.64% of the samples or 210 out of 279 analyzed displayed a urease activity at or below 0.05 pH units. Since 2012 (Ruiz, New insights on the urease activity range for soybean meal: A worldwide opportunity for the poultry industry. Arkansas Nutrition Conference) we have demonstrated that for solvent-extracted soybean meal (not for full-fat soybeans) the urease activity range consistent with tolerable levels of trypsin inhibitors for broiler chickens is the range 0.000-0.050 pH units. It is likely that the 36.39% of the analyzed samples that resulted in KOH protein solubility above 85.1% may somehow correspond with the 30.74% of the analyzed samples that displayed urease activity above 0.05 pH units. All these comments are, of course, approximations. Now, it is important to realize that there is also 10.95% of the samples that tested below 80.0% KOH protein solubility which may eventually be compromised as overprocessed (defining "overprocessed soybean meal" as containing less than 88% in vivo digestible lysine). Therefore, all in all, in my assessment 52.64% of the samples most likely are within the estimated adequate specs of 80-85% KOH protein solubility AND less than 0.05 pH units of urease activity (which in turn means being in the range of approx. 1.65-2.35 mg of trypsin inhibitors/g, or approx. 3.0-4.0 TIU/mg) assuming that the 52.64% from the KOH solubility evaluation is contained within the 68.64% of urease activity values below 0.05 pH units. For practical purposes this show the importance of ADJUSTING FORMULATION for specific soybean meal lots correctly evaluated for their quality parameters within the concept of precise nutrition. Nelson Ruiz Nutrition, LLC, Suwanee, GA, USA.

Nasser H Odetallah Nasser H Odetallah
Vice President of Sales
BioResource International, Inc. BioResource International, Inc.
Durham, North Carolina, United States
June 12, 2020
Nelson Ruiz Thank you for clarifying this to all of us. Regards
August 23, 2022

Gentlemen, thanks for the excellent discussion.
Going deeper, the KOH solubility evaluation is based on how much the protein was exposed to a Maillard reaction. Urease activity is an indirect analysis of how protease has been affected in the thermal treatment. Reading the comments seems to be correlated, but are different evaluations, or not?

Regarding the Maillard reaction, how much the protein fraction of feed could be impacted by an expander before pelleting, could it be a relevant issue?

August 24, 2022
Luis Fernando Vergamini Luna, yes, in soybean meal, particularly in solvent extracted soybean meal a correlation exists between trypsin inhibitors and urease activity. However, today it is easier to directly determine trypsin inhibitors because there are commercial laboratories available for such an analysis and also because we have a better understanding about the levels of inhibitors indicative of underprocessing of soybean meal for monogastric nutrition. In reference to the solubility of the protein in KOH, quantitative correlations have been recently established between solubility and lysine and arginine in vivo digestibility. Consequently, precise nutrition is realized when a nutritionist/formulator can adjust the ingredient matrix for soybean meal considering the specific KOH protein solubility results of a commercial lot of soybean meal. Finally, I don´t believe that we have enough data to support that the solubility of the protein of commercial soybean meal is affected in the expander (or conditioner) before pelleting. Most likely solubility below 78-80% is the result of overprocessing at the desolventizer-toaster during soybean meal processing by the solvent extraction process. Nelson Ruiz Nutrition, LLC, Suwanee, GA USA
September 15, 2022
Luis Fernando Vergamini Luna
We do a quick test of urease activity and view it as trypsin inhibitor. Not for protein analytic activity.
We use mostly mash form of feed.
I also do not believe in adding enzymes. I used and found them of no us.
Thank you
Indbro India
mohammad aslam mohammad aslam
Specialist in Animal Nutrition
September 16, 2022
Nelson Ruiz Explained well. Thank you
Mario E Tobar Jaramillo Mario E Tobar Jaramillo
Mechanical engineer specialized in metallurgical.
August 24, 2022

Nelson, good morning. Excellent your explanation. Best regards

dan hofer dan hofer
Poultry farmer
August 26, 2022
We got own roaster urease was .02 KOH was 77 birds seem to like it they get 1.56 Fcr
September 16, 2022

As always Dr. Nelson Ruiz is very clear in his explanation about SBM and how to measure correct industrial process. By the way a very short time about 14 seconds resident in the conditioner (before pelleting) is unlike to affect solubility of the protein. Alfredo Irazusta , Alinat SRL. Argentina.

September 16, 2022

As always Dr. Nelson Ruiz is very clear in his explanation of methods on how to measure SBM at industrial process. By the way, I do not think that a very short time ( less than 14 seconds ) in the conditioner before pelleting could affect protein solubility.

September 17, 2022

Dear friends
thanks for the discussion, I am very impressed with the quality of the information. Recently, we have tested different soybean meals available in our region, and it was possible to see this difference including AME, AMEn and other digestibility variables. This makes very important the information presented by Dr. Ruiz. This makes me more interested in continuing the studies about soybean meal quality.
Prof. José Henrique Stringhini (UFG, Brazil).

September 27, 2022
Thanks a lot for the great discussion.
Especially for Dr. Nelson Ruiz.

Nowadays we also have some different sources of protein, besides Soybean Meal still the main one and varies from 44% PB and going down to 48% PB.
These different sources like DDG, Canola, and SPC are also variable.
How to correctly measure and check their quality in the plant.
KOH for Canola Meal seems to be different from Soybean meal, maybe KOH 0,05.
The DDG initially with high moisture, is dried with lower control on checking the effect on protein quality.
SPC, that is a Soybean meal without molasses, which would be a fast check when receiving at the feed mill?

Thanks, gentlemen!

October 16, 2022
Luis Fernando Vergamini Luna
I appreciate your note. Each ingredient is different. However, the solubility of the protein in KOH (KOHPS) to evaluate adequate heat treatment is applicable to most oilseed meals without having to modify the concentration of the KOH solution. For instance, Anderson-Hafermann and co-workers [Anderson-Hafermann, Zhang and Parsons. 1993. Effects of processing on the nutritional quality of canola meal. Poult. Sci. 72:326-333] reported that commercial canola meals may display a wide range of KOHPS values from 80% to 40%, but only KOHPS values below 40% are correlated with overprocessing. In other words, each oilseed meal has its own MINIMUM OPTIMUM KOHPS VALUE. We have recently reported that for commercial soybean meal (solvent extracted) the minimum optimum KOHPS is 80% in the context of a KOHPS procedure standardized to be correlated with in vivo digestible lysine (Abstract M105, International Poultry Scientific Forum, IPPE, 2022). Additionally, we made available in the public domain the statistically significant correlations between KOHPS and in vivo digestible lysine and digestible arginine in commercial soybean meal (Abstract M106, International Poultry Scientific Forum, IPPE, 2022). Therefore “precise nutrition” is possible as far as soybean meal is concerned for its protein quality. Both abstracts are available upon request. In reference to DDGS, it is important to understand that it is a very variable ingredient from supplier to supplier, and probably between lots of the same supplier. If you have a NIR machine in your company then you have the opportunity to calibrate at least for the proximate analysis for DDGS (and other ingredients) and then use some of the regressions that have been published by several authors in the U.S. in recent times for DDGS at the Poultry Science and Applied Poultry Research journals. These journals are now open access, therefore you can access PDFs of scientific papers free of charge. Nelson Ruiz Nutrition, LLC Suwanee, GA USA
October 17, 2022
Thanks a lot for your comments Professor Nelson, It is always dense information that helps a lot.
Some soybean products like fermented soybean meal or Soybean Protein Concentrate, have lower reactive molasses toward a Maillard Reaction. The industry is still trying to determine the values of others with this same KOH parameter, how to build suitable and friendly check-in analyses would be great.
Evonik Animal Nutrition Evonik Animal Nutrition
Rellinghauser, Hessen, Germany
October 12, 2022

Dear Luis,
in the last few years, we had a close look at the quality of different protein-rich feed ingredients and we developed NIR calibrations which can now be used locally to estimate the quality. The reactive Lys to Lys ratio is a good indicator for over-processing and it works in Soybean products, but also in Canola Meal and DDGS. In Canola it might be worth to check in addition the levels of Glucosinolates and Erucic acid. It should be low, but it's better to check it.
All the best,

October 17, 2022
Thanks a lot for your comments Markus.
Reactive Lys has been the primary safe data to manage but it is not a friendly analysis to check truck loads.
The calibration of soybean products with lower molasses. Are they available in the new database?
Products like Soybean Protein Concentrate or Fermented Soybean meal.
October 16, 2022
Unlocking the different parameters to know the exact matrix of soya and other meals.ad vomment by Markus NIR evaluation is fast correct way to assess quality. Higher inclusion rate of meals could make a negative effect if the quality varies, in current days and time to come as the price reduction is not in sight.
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