[Music] thanks thanks so much thanks for the invitation I'm really pleased to be here thanks serving and for the introduction so yeah look what I'll I'll be just going through today I'm quite excited because um we have some new data that I'm gonna be sharing with you today I'll be focusing almost entire my entire presentation to feed intake although after after the recommendation from the previous speaker yeah I don't know how much we can do nutrition right but we'll try to review what I in my opinion it's known to date when it comes to manipulating the diet especially as I said looking at food intake and then I'll introduce you to some of the mechanisms that we are we have been looking what's behind our work is more than getting the exact level of such-and-such amino acid more than that what we're interested is in understanding the whys why is that happening with with the principle that if we understand what's going on then we can apply our knowledge to just any circumstance so really when oops I think I'm going too fast really when it comes to to feed intake and feeding take control I would like to to mention the work from Michael Forbes and definitely when thinking about heat stress the first thing that comes to mind is uncomfortable right you feel quite uncomfortable and and that came to my mind the theories or the principles of Michael Forbes saying that feeling take basically and in hypothetically it's a game of adjusting the intake of nutrients to the minimum discomfort that's how animals tend to look at the feed do I feel better or I don't feel better and then you adjust that intake as we go on a long-term basis now those nutrients over here therefore the optimal minimal discomfort will depend on what type of nutrient we'll look so it's a complex balance between energy protein amino acids obviously and water holding capacity although these that I have to say is from a publication in pigs but it might be relevant also for other animal species in my opinion so feed intake is my my seam and FinTech is what I'm gonna be talking about and us will look at and I'm not gonna go through the physiology in detail of how heat stress and the general stress system works but it's I think relevant to point out that a number of the physiological mechanisms related to stress have a direct impact on feeling take all right so let's say when when we enter into the activation of the hypothalamus pituitary and adrenal axis what you season an increase in those catecholamines epinephrine and norepinephrine which have a tremendous impact on first changing the redistribution of the water pools blood so blood just stays away from internal organs the digestive system and go to the peripheral tissues and that has obviously tremendous impact in everything in all these tissues and I think it's been mentioned before that one of the consequences would be that gut integrities probably put under under pressure right so not on therefore because the gut function therefore gets disrupted we will have some leakage and I'll talk about it a little bit later on which which may interact with the immune system an immune system that as the previous speaker said it's down it's down regulated it's not so active it also impacts a number of what we call got peptides cholecystokinin glp-1 and so on which have a tremendous impact on feed intake they are actually the main cornerstones controlling feeling taken in birds in overall just an overall assessment that let's realize that the hypothalamus that we is the main organ controlling feed intake is also the main organ in hyper in thermal regulation regulation so thermal regulation feed intake in the hypothalamus they are neighbors that doesn't mean that two neighbors talk to each other and I see some smiling faces yeah maybe you don't talk to your neighbor but you know it's easy that you talk to your neighbor that if you that you talk to somebody else in Australia right so overall what I'm gonna be doing is trying to understand some of these mechanisms that are initiated with heat stress and that have an impact on on consumption in chickens now we did before we started all this project on heat stress which was not a long time ago was about two three years ago so the results I'm bringing today are quite fairly new we obviously have had a look at the literature and we we looked at what was already known on manipulating the diet that could be related to heat stress this is a summary of some of the publications that were highlighting potential positive impacts of a number of feed additives right this is the case for plant extracts and oils somebody has already been mentioning about reducing oxidative stress maybe got health probiotics and prebiotics similarly organic acids and even enzymes and we do have an speaker that will address enzyme with all the specificity that it takes but all of these additives have shown at any given time some potential impact on improving heat stress and particularly intake now this is a busy slide but it's an important one I would like to spend some time in explaining what it means now this is a literature review or almost meta-analysis if you want not the statistical modalities but a meta-analysis and each one of these dots represent in fact peer-reviewed papers that address the topic of heat stress and dietary manipulation so there's a number of them but let me say that it was quite disappointing to see that a lot of the papers published on heat stress lack the proper control which would be say a thermo neutral room or environment right so you end up what it looks a lot of dots but in fact there were probably five times more dots on heat stress publications but I didn't consider them if they didn't have a proper control because I believe they could be misleading right so in any case what we're seeing here in the center Center column is feeling take impact on feeling take of a number of different feed additives right and again these are averages of five six ten twelve publications whatever number we found in each case now all we see is the the dark boxes refer to the heat stress treatments while the white boxes would be the control thermo neutral and the line says what happens when the heat stress group gets supplemented with this additives here so if I push the line towards the right of the dark box that means that I'm helping to increase feed intake right and getting hopefully close to the thermal neutral environment so as we go across you will see that there's a couple of feet additives that maybe we should highlight as having an impact on feed intake and those would be according to this graph GL n GL n stands for papers working with glutamine or glutamic acid supplementation right so we would appear that glutamine glutamic acid it seems to push the line almost outside that the the dark box right so increasing intake similar for arginine and lysine you see here increasing the arginine lysine ratio it seems that is also pushing the line outside the dark box right and number of others like chromium seems to have also similar effects or selling selenium and all that so that's the regarding feed intake but I would like to drive your attention in something really important and it's not all about feeling take because now if we look across and we see what happens with body weight gain vwg you will see that in some cases there is a good relationship an apparent increase in feeling take you also see apparent increase in gain but not in all the case so feeling take when it comes to heat stress not always feeling take equals improved growth all right and we should keep that in mind you now be talking about this later on because our own data just point at the same into the same direction now this is the fifth conversion ratio column now so I said about fidelity but we also looked at and still in this meta-analysis we looked at macro and micro nutrients and how they affected heat stress and and I'm just warning that the next slide might might look a little bit scary but I just want to make a point that there's a number of publications addressing caloric density in general having a higher higher caloric density in the diet seems to help fairy type of fatty acids have been addressed crude protein but also some amino acid supplements as well as vitamins and minerals now this such a busy slide and I apologize for the busy slide but it actually just wants to make the point that I would rank that most of the publications on manipulating nutrients in the diet refer to either energy or amino acid and proteins and this the for a robust evidence that through manipulation manipulation of energy basically increasing dietary energy density and amino acids we can probably modulate the negative impact on heat stress now it is it was our objective and I'm going to be showing some of our data now that we wanted to reproduce a little bit these paradigms so playing a little bit with protein and energy not necessarily to discover anything new because that was already done but I wanted to have a model so that I could address mechanisms of how would that happen what nutrients when and why right so we had a first approach on playing with low energy with society on the heat stress or seltzer minuto and well we've got a little bit of a surprised we did have a significant effect on on energy for the average daily feed intake showing that feed intake was increased in low energy which just makes a lot of sense nothing new there but we couldn't really find an energy effect on either gain or or conversion be disappointed but uh I thought well no there's something in feed intake so we'll keep that in mind we did a second trial then testing protein so what happens with a low protein in a high protein again we were just trying to repeat work that had been done in the past just trying to get the model right and well what was what we see was a strong effect of protein for average daily gain and for conversion ratio so that high protein would improve the heat stress and the growth overall but but not feed intake no impact on feed intake but impact on growth and conversion ratio no so that was all good so we thought right well if both trials are pointing at a direction of one low energy for feed intake and the other one high protein for growth why don't we put them together so we did we had a two by two two levels of energy two levels of protein by two heat stress and thermo neutral and and we studied therefore whether there was some synergy between having a high protein and a low energy whether we could reproduce our own data on on the low energy and surely now when when we look at average daily feed intake we have a significant effect on on protein so that the high protein here number two and number four would just have slightly so it slightly lower than the but not significantly actually and the energy intake the energy effect was significant because the low energy groups three and four were clearly above the high energy so the lower energy intake again was very significant and again it didn't necessarily come up with an improvement of average daily gain right but it did say the protein having an impact where high protein had an impact on average daily gain and it is true that the there was now diet to environmental interaction so that those effects were across environments so I'm not saying that those effects were only visible with the with the heat stress treatment right now now something that I would like to highlight is the relationship or the association between feed intake and gain I mentioned before when we looked at the literature there's no no consistency that at least in heat stress feel intake will be driving gain or vice versa now what we've seen here is that in diet one and three which were the low protein diets we see a significant relationship between feeling take an average daily gain in bhau's in the high-protein diet that relationship is lost with UCP values above 105 excuse me what is that telling us so that the low protein diet somehow the birds are craving for protein they are the protein is limiting the development and that's what I think we're seeing here and we took that as a sign that obviously amino acids and amino acid related metabolites might be crucial under these conditions so I took the the the we took the research to the next step and so alright so how is the heat stress therefore potentially affecting the sensing of protein and amino acids in particularly amino acids right we do know from humans mammals and even birds that when we're under stress and that includes heat stress our capacity to send food and to sense nutrients is diminished right in some circumstances and with with normal water availability it may actually increase when some circumstances if it decreases like for example and one of the reasons is that when we looked at the taste sensory cells in the oral cavity all these sensory cells Co express these adrenergic receptors which will respond to the noradrenaline and appearance of the catecholamines so when the queen we're under stress catecholamines are released from the adrenal gland and those catecholamines hate the receptors among others the receptors in the oral cavity and in the in the taste buds so that the taste buds sensitivity changes how does though how does this sensitivity change well for some harm so for some type of taste like Saudi a salty taste may slightly decrease for some tastes like bitterness and even sour taste it actually increases the sensitivity so we're more sensitive we're more alert of what's going on right so now the question and I quite often I talk about tasting avian species and and I I often get the the question still today that ah but birds can not taste can candy right so the answer is is that the birds can taste at least as well as we as we can and I think it's a it's a bit of a it's been a bit of a misunderstanding over past years that's just thinking that birds were not able to taste right now the evidence now they tells us that when we look at the number of taste buds here over bali way birds are very much in the middle of the graph so they are as good as the as you would expect mammalians to be at least from say anatomical perspective so from a physiological perspective now in addition only recent data has published showing that the number of taste buds in Royalists were underestimated when we looked at the real number that has been published all only in the last year or two in fact the number of taste buds per size of the oral cavity it's actually probably much higher than than as in humans right so I think that's something that we need to keep in mind so why chickens have been on this part of not having taste perception well the several reasons one is because they don't have taste papilla but all of us mammalian species we have taste popular so all these taste sensing cells are grouped are clustered in taste buds and taste buds are in an organelle that it's visible in that to taste popular in birds you don't see that because they don't have a taste popular so if you're just looking at the tongue or an oral cavity of the bird you say they don't have this papilla they might be probably tasteless right but that's not true because what actually happened is that taste buds are still present in the oral cavity except that they are not in taste papayas what it's not existing are the papayas but the taste buds are still there right so the capacity is intact right so lack of salivation it is true that birds have small quantities of saliva being produced not large like in mammals but what you will see and that makes a big difference when it comes to to the way the taste system works in birds is that what you'll see is that the taste buds in birds are around the salivary ducts so the little saliva that's being produced is actually very efficiently used by taste buds because they are in the salivary ducts right they are not spread all over now the other thing that it's important to understand is that when we looked at our taste in mammals invariably always we look at what the tongue but in birds if you look at the tongue its keratinized there's nothing there it's just it's just a physical help to solo the feed in actually the tongue just pushes the feet to the upper palate and then it's just processed now so where would the tastebuds be then if I push the feet to the upper palate and squeeze it there a little bit that's the perfect place to actually sense fit right so that's where birds have their taste buds in the upper palate so you need to look at the right place to actually be able to find the taste sensory system now so there's also known that the number of taste genes in birds is reduced and that's partially true partially not true it's true when it comes to bitter taste we have humans have 25 beat the genes for taste taste perception and birds have only three but a recent publication from a German group just show that those three taste receptors in birds account for 80 percent of the bitter compounds in humans all right so they are widely tuned and they are still capable of sensing a lot of different bitter compounds now now the low the low numbers of tastes but is actually probably not true it used to be that it was 304 broilers but now today we know that it's more than 700 using different molecular techniques so that's what I explained before that's the salivary duct and as you see the the different taste buds are actually close to the salivary ducts due to the slow amount of saliva being produced by birds and this is the genetic the genetic the genes involved in taste sensing in birds and as you see when we looked at sugars carbohydrates fatty acids but also amino acids all the genes that we know in mammalian species are also present in the chicken not all the T 1 or 2 which is the sweet taste receptor in mammals is missing in the chicken however we do know that she consents glucose and send some sugars through a trans porta which will go as glp-1 so I think that chickens still can perceive glucose and in simple sugars but all the rest of the machineries there I would like to point your attention to these two genes here T 101 and T 1 or 3 these are classic in humans classic you mommy taste so they send savory but it's related to proteins is related to amino acids right now when we when we talk about this and I like this because we have some data about how heats heat stress affects these couple of receptors now I'm going to skip that slide but it really says a bit the same that the previous slide the chicken tails receptor genes are close relatively close relatively conserved compared to mammalian taste system and and those are the homology of different genes from the chicken to to human orthologs right but I'm not gonna stop there and go ahead with what we know about these genes being expressed in the chicken in us you know as you see here all of the genes that are of interest including sdlt one which is the glucose transporter are highly expressed in the oral cavity of the chicken right so they are they're perfectly expressed similar levels than humans so this absolutely no reason why we should believe that chickens are not able to taste to the same extent that we humans do now the most fascinating the most fascinating story about taste is not related to taste now taste is in the oral cavity perception of nutrients in your cavity relates to the gustatory cortex in that state but the same nutrient senses the same taste sensory cells that have been described in the oral cavity they happen to be present in a number of different issues along the gastrointestinal tract and they sense nutrients in the Western intestinal tract which help then control feed intake by releasing got peptides right so an out on poops and out on pro ventricular because what we have found over the years is that the expression the presence of nutrient sensing cells improvin ticklers is really high it's much higher than in the oral cavity so when we think of taste we think of oral cavity extra orally we have other organs that express higher levels of these taste sensory cells and thats related to metabolism and related to control of food intake now in this I'm going to be presenting some of the very recent data that we have looking at a number of genes of interest that is receptors for amino acids t1 ours calcium senses receptors also amino acids sensor GPR cystic day and all amino acid receptor and GPR 92 which relates to pep tones right we also looked at Gusterson which is a typical biomarker for taste sensory cells and these are glucose SGL t one is for glucose sensing glucose transporter and this is a glucocorticoid receptor since we were looking at in some stresses right and i'm showing only data from the oral tissue and the province reckless and we have a number of other tissues that we haven't analyzed yet so all right I'll just be finishing very quick now as I said there's a very significant if there's a significant effect on tissue so the province the the expression on the province nicholas outruns the expression on the upper palate so the province equals is exquisite sensitive organ and that's the explanation on how those sensory cells when they are stimulated by amino acids they release the number of got peptides that have an implication on the hunger satiety cycle and one of the main main messages today is seeing that particularly these amino acid sensors T 1 R 1 and T 1 R 3 are up regulated and the heat stress conditions right and it's sending therefore a message of the bear it's actually craving from some amino acids and I'll be just very quickly mentioned so so we do know that these amino acid senses amino acid receptors have affinity for a number basically all of the amino acids that are relevant for animal nutrition now these are known in mammalian species but in chickens T 1 R 1 T 1 or 3 have a very high affinity extremely high affinity for alanine a little bit less for sealing and we're saying that the receptors for our inin Syrian chickens are highly expressed when there is stress such as heat stress or something to to be considered and I'm gonna since we're running out of time what I'll do is just I'll skip all the integrity data but just to mention that there is obviously an opportunity to revisit how that integrity may have an impact on some of these nutrient nutrient profiles now I'll finish up with a summary of what I've presented and basically what I've tried to do is if we look into the literature deeply we will see that there's some evidence is that some feed additives have a potential impact on intake they can and they do increase intake especially as I have mentioned some of the amino acids and some of the ratios now when we've looked at trying to set up a model we've seen that Low Energy is actually increasing what consistently intake and the combination of low energy with high protein may actually be quite positive to deal with it stress now our work on the mechanisms point at some amino acids that we had not considered before and that might be interesting and important I said based on literature I said about glutamine and glutamic acid but I'm also saying here that some of the receptors related to alanine and Sirian may also need to be considered and with that I'll just would like to thank my Nadia sharam [ __ ] in bed to work that have been working on these projects and thanks to them I've been able to be here presenting this story so thank you very much thank you dr. Arora this is I think a very important new perspective and it tells us that there is potential I suppose by going towards you know formulating a balance between the amino acids that could be very very important under heat stress conditions are we getting the questions Pierre Andre do I [Laughter] so when if we just go through them one by one as far as we can with the time limits you did not include enzymes in the group of additives that could help to keep the feed intake could you comment on this yes two reasons one I would say yes the enzymes they were in in the slide I what is true is I didn't make any specific comment on enzymes because I was just afraid that somebody that knows more than I do on enzymes will be speaking after me so I said no I'll let professor Chuck talk about enzymes and I think that's where right and then there's a the other question is that and do you think that we can pre stimulate feed intake before hatching I mean could that help us but there's a there's another talk about this maybe we should skip that one Arrakis there's an we have a talk on this this afternoon isn't it yeah so what else have we got what about water intake and the capacity of the birds to look for water is there you know the physiological aspects could that be related to yeah yeah yeah yeah there's some some sensory scientists that that consider water as one taste and and the reason is because taste sensors say they actually Express a water receptor which is ubiquitous it's probably nothing very specific and that's why the controversy is whether it should be considered taste or not but it is clear that that we have senses that are specifically addressing water and water needs so the answer is yes birds chickens do have our co-parents like mama so again when it comes to nutrient sensing these are very conserved mechanisms in general and so so so conserved that we can you can still see that that conserved conservation between such two different animal species such as birds and mammals there's just one more question which i think is fascinating when you look at taste receptors and then thinking about you know energy replacing like carbohydrates by fats does it affect you know like taste and feed into could it have an influence on feeding take well yeah look in in certain in certain stress situations and I'm gonna be referring now to a feather pecking project that one of my PhD students has finished and what we found with laying hens that that are being packed the level of cortisol is increased and they are craving for sugar so if we include sucrose and glucose in Birds being fed a peg we might be actually helping the weaker birds right so the answer is yes there is some interesting work about this these effects yeah that's correct thank you very much I think we covered most of the questions and so that gives us a good idea I think about the the role of taste receptors in relation to heat stress thank you very much thank you thank you [Music]