[Music] ladies and gentlemen welcome from my side as well the previous speakers have perfectly perfectly set the framework so we can directly dive into a more specific topic now and that is on phosphorus under the framework of sustainability what you can can often hear or read these days is that people say with the improvements that have been made in plant phosphorus utilization by using modern fight aces a big step forward has been made in regard to send sustainability this definitely is true but this is probably only one part that we need to consider when we talk about phosphorus efficiency and in this presentation I would like to address the question whether problems are solved or perhaps we still have problems to solve so phytate destruction is one of the topics that I will talk about but we will also talk about phosphorus evaluation in a more general sense and we definitely have to talk about phosphorus requirements and dietary allowances but before we start with that I would like to say a few words in regard to sustainability whenever we talk about or whenever we use phosphates we have to keep in mind and that has been set before that we are dealing with a non-renewable and even worse Fe neat resource what you can see here data from the statistics of the US Geological Survey they continuously predict what happens in regards to annual world mining not only in phosphorus but also in regards to other minerals but you can see the data for phosphorus and you can clearly see that in the past 15 years or so there is continuous and quite considerable increase in the annual phosphorus mining and this is expressed in teragrams which means ^ 12 related to this is a prediction of how long the resources or these reserves might still last and you can see that in 2017 the prediction was approximately 250 years and only six or seven years earlier the prediction was even 100 years longer this illustrates that these predictions are to some extent weak and in fact there are other statistics around let's say the time is even shorter but the respective of whether we have 50 years more or less we should face the situation that there is an end and we should take that very serious for the sake of the future generations because all living organisms depend on the continuous supply of phosphate microorganisms plants animals and of course human beings and regarding to economic aspects of sustainability this picture perhaps is even a little bit more complicated what you can see here is the distribution of the global phosphorus reserves on globe you can see where most of the phosphate is stored you can see that there are some resources also in other countries and the you not even appears in this statistics as a separate category which clearly shows that we depend to a very large extent on imported phosphates and when you add another circle to this graph then that shows the last year's distribution of phosphorus mining among these countries you see that approximately half of phosphorus mining happened in China and when I have been the about half year ago and could speak to some people they said that predictions for the duration of phosphorus reserves in China still to be there is approximately 35 to 40 years and imagine what happens when all these amounts also need to be generated from other countries this clearly is a matter of economic vulnerability for Europe so in my opinion handling the sustainable handling of phosphorus phosphorus resources is the challenge for sustainable food production long before protein and also long before energy why because we do not have alternative sessions like we had yesterday on protein will not be possible on phosphorus and of course you might say yes that livestock is part of that but more problems and more amount of phosphate is needed in other parts of agricultural production that's correct there is a lot of phosphate needed for fertilization much more than four feet phosphates and it's also true that the question how phosphate recycling from human excreta is managed is the biggest challenge all of that is true but let's face the situation as it is we as a livestock sector also have to make our contributions and that is what I would like to talk about in more detail now so when we look at the factors that are relevant for phosphorus utilization and when we roughly group them we can do that in two feet related factors and animal related factors and we have aspects such as animal species growth rate egg production and so on on the animal side and on the feet side we have of course the question of binding form of phosphorus we have the question of feed additives phosphorus concentration calcium concentration in the diet and so on and so on and according to the philosophy of WPS a both these blocks should be brought together in an evaluation system that is based on digestible phosphorus in order to bring both these groups of factors together as good as possible so when we now talk about the feet side first of course I have to show you this here phytic acid abbreviated as ins be six this inositol ring system that carries six phosphate groups and that often because these phosphate groups are negatively charged is associated with some cations and depending on what the ph situation and the digestive tract is we may have other molecules also bound to it and in order to utilize this phosphate it must be released from the ring system and what you can often read still in textbooks and in recommendations is that this phytate phosphorus is hardly digested fully digested not at all available and so on and so on in poultry this is a misconception we now know that considerable part of this fight it can be utilized by poultry even under conditions of no phytase contained in the diet but that is a different story we don't need to touch today and focus on the point that fight ate is the major storage form of phosphorus in our plant seeds and also of course in many byproducts that are produced in the food sector and also in the industry sector and just to give you an impression I took a few data here from this excellent pioneering work that our colleagues in Belgium did about 20 years ago you can see the phytate phosphorus concentration in different raw materials to the bottom we have the cereal grains with approximately 2 grams of phytate phosphorus contained the oilseed meals on top with approximately three to four grams of phytate phosphorus and several byproducts in between highly variable fighter it phosphorus concentrations and when we express that as a percentage of total phosphorus we can see that many of them are in the range of between 60 and 70% the proportion is a little bit lower and the oilseed meets because we know that some the phosphorus dephosphorylation already happens in the production process and you can also see that some byproducts are have even higher phytate phosphorus proportion and others that are never underwent a certain fermentation process have less so just consider there is a big variation in the raw materials that are in use when we now come to the question of how much of this phosphate can release from in species in the digestive tract I would like to show you some data form from broiler chickens I have to say that quite many papers recently have been published on that there is a lot of information now available on that and I apologize that I only show you as an example data from our Institute that is simply because I have been I am in the wonderful situation of having highly talented and motivated young people working with me so I think it's only fair that I use the data in this presentation here so what you can see here is from an experiment that was done using may soybean meal based diets and samples were taking at the end of the ileum and when we can start from the left when we start from the left that was the diet that had no phosphate edit and only a low calcium concentration you can see that in six disappearance is roughly 60% and when calcium is edit it's not much less but when phosphate is added it goes down and that is even more pronounced when phosphate is added together with calcium so that is something that we very often see we have a very clear interaction between phytate breakdown in the digest tract and phosphates and calcium supplement it to the diet when we now at phytase to the diet and this is at a level of one thousand and five hundred units then you can see this sharp increase in phytate breakdown up to ninety percent and only minor calcium affect still remains to exist which reminds us that we should not forget about the negative effects of oversupply of calcium under these conditions so as I said before many other many more data are available on that and I think we can say that in six breakdown of ninety percent or more generally spoken is no longer a big problem which on the other end means there is not much more room for improvement when we now link phytate breakdown with phosphorus digestibility ladies and gentlemen we can do that in using data or studies that measured both in species disappearance and phosphorus digestibility and data for some experiments are shown here and when the linear regression is calculated through this data you can see that with each gram of in species phosphorus that disappeared approximately 0.8 grams of digestible phosphorus were released which means that approximately 0.2 grams will not digest it and that is the contribution that the lower inositol phosphate bring that still exists in the digestive tract and to show you this I took some other data here what you can see is the total in this case it's not disappearance its concentration measured in ileal digesta the concentration the total concentration of all inositol phosphates and the different combinations of phosphorus calcium and phytase we don't need who spend too much time on that you can see that is the predictable up-and-down but what I would like to show you is the distribution of this phosphates on the different inositol phosphate isomers and what you can see is that although in species disappearance increases a lot with the inclusion of phytase and we reach this very high level we still have some part of phosphate still entrapped in lower in acetyl phosphates and quantitatively spoken this is approximately 20% of the phosphorus that remains bow bound in lower inositol phosphates and this is something that perhaps still can be improved so we should remain with the vision that all the phosphate groups should be released from the inositol ring but I'm not sure whether this can be done only by further improvement and by further enzyme engineering but that is probably part of the story so to show you also some data on laying hence ladies and gentlemen they are not so many data available in laying hens but some of these data are available for quite a long time from our colleagues in the Netherlands that studied phytase effects at different calcium levels on phytate breakdown in laying hens and to keep a long story short I would say that in principle although the calcium level is much higher in layers than embroiders in principle the responses appear to be similar with broilers including and this has been studied in a very recent experiment published under the lead of the colleagues from the University of Leeds the release of myo-inositol but I said before only very few studies are available and I should also say that effects were not consistent in all of the studies that are published so there is probably still some work to do in laying hands on that and that also seems to be the case for turkeys we know for quite a few years that when we have a look at total phosphorus digestibility phosphorus digestibility and retention is much lower in turkeys then it is embroil and we had a look at phytate break down in the digestive tract again using low phosphorus diet and in this case the diet was meat mixed with four different cultivars of maize I don't need to explain what the reason for that was but this was investigated then these mixes were investigated in turkeys and you can see the in species disappearance in turkeys for these four diets with and without phytase supplementation and it is on a fairly low level though with a clear phytase effect this experiment was also done you in broilers not using the identical diets but using the same mace cultivar so we cannot 100% compare this or consider this to be a species effect but we can take this as a very clear indication that we have big differences between broilers and turkeys in regard to in gastrointestinal phytate breakdown so different differences between growing species exist so getting back to our questions to our question other problems solved I think we can say that in regard to phytate destruction and with a focus on broilers yes these problems are mostly solved there still is a little bit room for improvement with a specific focus on this lower inositol phosphate rather than on in species but for laying hens and other growing species we probably need more data to call the problem solved let's now come to phosphorus evaluation in a more general sense I would like to make that short and those of you who already attended this symposium 10 years ago at that time in Edinburgh may have seen this slide here that was presented they are in a session that was dedicated to phosphorus evaluation and we have seen here that in regard to phosphorus evaluation system used and terminology very different things are around and caused a lot of confusion and this confusion was against making improvements so as a consequence of that working group number two decided to start phosphorus working group and one of the results of this working group that was a suggestion that the standard method for the evaluation of phosphorus in future should be based on the adjustable phosphorus and this is what has been proposed determination of pre-sequel digestibility of phosphorus using a standard protocol so in that regard a lot of progress has been made and there is a clear definition of what the European Federation of WPS a considers to be the future phosphorus evaluation system having said that as I said us want to keep that short I think that with this agreement on that summit protocol of digestible phosphorus a big part of the big a big proportion of the problem has been solved although we have to say that we are still lacking data for raw materials some experiments have been done in recent years but there are still more needed on that and with that I would like to come to the last part of my presentation and that is on phosphorus requirements and dietary allowances ladies and gentlemen yeah there are different approaches around you can do that empirically or you can the more pictorial kind of modeling and when you look in what is published and what is used we again have the problem of diversity in terminology and in the different systems that are used around the globe and here in Europe at least people who belong to the working group nutrition of WPS I agree that this should be done on the basis of a modeling of dietary of digestible phosphorus requirements and in fact that is a fairly simple principle behind this factorial approach the most important point that you need to know very precisely is the phosphorus that is contained in the gained body weight but that is something that can be done I mean it's a hell of a lot of work but it can be done relatively easy but it needs to be known very well because that is quantitatively spoken the most important point and you can then calculate the digestible phosphorus need per kilogram gained body weight by simply utilizing a value for the efficiency of utilization of digested phosphorus which is quite high and when then additionally inevitable phosphorus losses which are relatively low are considered and feet per gain data that are available all around then it is very simple to calculate the phosphorus the digestible phosphorus concentration that is needed in the diet and you can then from that easily calculate the total phosphorus concentration using digestibility values for the raw materials and phytase effects and this approach has been used by our colleagues from from England under the lead of Tata now see and they have presented this model two years ago at this conference and I use this model and took some some other data from the breeder performance objectives to to to get hold of FC our values and what you can see here is the digestible phosphorus concentration that is needed depending on H of course that depends on what strain we talked about in feed efficiency details and so on and so on but we only talk about the principles here and there is a clear potential towards a severe reduction with increasing age and when it then gets to the question how much total phosphorus is needed in the diet then of course the question of digestibility is the most important here and if we take an example the 21 days old broiler here and assume a phosphorus digestibility of 60% then we end up at about five point five grams of total phosphorus and of course when when we go go up to 7 PT 70% of phosphorus digestibility we can go down with total phosphorous and if it should be possible to achieve 80% of phosphorus digestibility then it can be even lower so this is much lower than many of the data that are still around in textbooks are given by official committees and also much lower than data that are given by the breeding companies of course this has to be go and this has to go hand-in-hand with adjusted calcium concentrations in the diet so an alternative is to calculate this requirement estimates on empirical approaches and I like the work that this French Canadian group is doing on this and similar topics a lot so they use meta analysis to estimate in this case non phytate phosphorus requirements please do not mix that up data on digestible phosphorus will not are not yet available to do this kind of calculations you can see what kind of data they have used here different combinations of calcium and phosphorus in the diet and also phytase and then they predicted the non phytate phosphorus requirements for different performance traits and for different combinations in this case of calcium and phytase there are quite many data in the body of that table we probably don't need to bother with in detail and we can just summarize that more non phytate phosphorus is needed for bone mineral as I for bone mineralization sorry then for gross and that more NPP is needed when calcium is in excess that is what we have seen already before and of course when no phytase is supplemented well the disadvantage with this is that we do not we have to set certain conditions here and cannot model it nonlinear but the same principle relationships are reflected in this meta-analysis as well when we finally have a look at laying hens a couple of years ago a colleague who visited us from Iran did similar meta-analysis on data that were published at that time on laying hens again based on NPP not on the adjustable phosphorus you can see the data description displayed there and the non phytate phosphorus concentration that was needed for this different traits here is presented of course again depending on whether phytase is contained in the diet or not and you can see the range of NPP that was calculated from this data so we can go down to approximately 1.4 grams of NPP or let's say 2.2 if no phytase is contained and very recent our colleagues from the University of Manitoba have published a study where they investigated different levels of NPP and studied a lot of phenotyping traits here and concluded that 0.15 percent is enough and does not affect health and performance of layers well I would not say that I would not generally say that we can go so far the only in our general recommendations because this was only a 12-week study but it shows the potential that exists and is specifically in laying hands there is a big room for reduction in phosphorus concentration and in some chats that I had with some of you during this conference and before my opinion was that some people in the industry already collected a lot of experiences with that under practical conditions so in regard to the question whether the problems are solved I would say that we still have to work a lot on that on this aspect of dietary allowances we need a refinement definitely and we need more flexibility in the models we have a digestible phosphorus model already existing and we should work on the adjustable phosphorus models for layers and other growing species as well so to sum up and picking up again the question of sustainability or taking taking the viewpoint of sustainability in my opinion we can say that the community can say that in regard to phytase destruction we have well done that in regard to phosphorus evaluation we also have done a lot of work but we just need to do a little bit more on raw materials but in regard to dietary allowances we better feet up in order to become more sustainable in regard to phosphorus well with this I hope I could give you some food for the discussion and I thank you for the attention [Applause]