[Music] so maybe we can we can then go ahead and and present the the first speaker his Michelle dewclaw he's coming from from France from Andhra he got the PhD degree from the legendary a very famous national veterinary school of Lyon a beautiful place and he's been working in interestings ever since he's now the leader of the research team nutrition and Breeden schemes and well his member of a number of scientific societies and of course contributor of many different papers and also a participant as a speaker in many different international conferences so peace welcome Michelle the cloth for the first presentation yes thank you I want to say that this presentation was originally meant to be made by your system being with the specialists on networking on the subject for about 20 years unfortunately we could she couldn't break it and attend this meeting so she asked me to present a world so the work is entitled from Muslim to meet physiological and metabolic basis as you all know and as we already mentioned there is an increasing demand in Putra meat worldwide about an increase of 2 percent per year and there is also a rapid evolution of market share because as you can see on on this figure the sales as walcker castes is constantly decreasing why the same as cuts and further processed product is increasing so there is a change in the expectation of the consumer and the quality traits that are important are changing of course this imply an interest for materials also an interest for the functional properties of the meat its storage of ability sensory perception remains of course an important issue nutritional value is important and as we already mentioned image of the production system is a very important topic in relation with the perception of animal welfare as you know with this increase in demand for poetry an increasing demand for further processed product there has been a tremendous increase in the performance of poultry as illustrated the animal ash at iron weight and they grow much faster than they used to which means that the same age you have much bigger animal and also the conformation the meat yield has tremendously increased this has been a compare it by an increase and anomaly rated feed efficiency emulated growth rate and ameliorated rest mediums so as a consequence if you want if you target your production to a bird with a certain body weight usually the world market is 2.2 kilogram life weight it means that you will slaughter you your animal at much younger age so the consequences are that if if you if your target is a wall Caracas so this body weight of 2.2 kilos you will end up by slaughtering animals at younger age that than you used to on the other runs as there is a high demand for further processed products it means that you need to produce high amounts of meat and especially a great breast meat which is the most processed you will end up with of your chickens which in this case will be older so what has changed as you know muscle is composed of muscle fibers which are multinucleated cells very large cells which have contractile properties and you see here some images what has happened along with the increase of of body weight is the size of the fiber expressed you know as surface in micrometer has increased a long time with selection here you have numbers which were obtained by sea Seabury in 2005 and nowadays at the same age there is about a 50% increase in the size of the fiber or if you take it the other way around it means at the same roughly the same body weight but older was slightly higher body weight but younger animal you still have a bigger fiber and if you go to the production of Eddie broilers then you have really you huge fibers and they are very big also compared to other species so for it is a bit by design your group has conducted characterization of this ad broilers and was what she found apart from this very large increase in muscle fiber size is also modification in the biochemical characteristic of the muscle we've both increased lipid and increased protein contents also and this is what I will comment in in the later slides there is modification in post-mortem metabolism so this is to remind you what happens post mortems there is a rapid pH for which is a key element from it quality so usually you have a first stage of so you have a very sharp decrease in pH and after a while you reach the minimum value which is called the ultimate pH and we this is usually measured 24-hour post mortem while we can also measure under knee pH usually 15-minute post mortem so the normal pH values for ultimate pH are from five point seven to six point one and as we will see that is very variable and this is what happens gives some defect if the pH drop is very fast this leads to what we call pain soft and exudative meet a condition which has been described in the past especially in turkeys and somehow in chicken but especially has been the object of many many studies in pork and doesn't seem to be a real problem at the moment in Reuters another problem of low pH is what we call a submit with a pH which is below five point seven and which gives characteristic which has are somehow similar to PSE me because the male is also pale exudative becomes tough after cooking and it has low processing so that's quite that can be quite an important problem on the other hand you can end up with pH with with meet with I pH higher than six point one which is called dark famine right because the meat is dark it's from after cooking it has a dry taste and the shelf life is is reduced and this situation either low or I ultimate pH linked to like against or death so what has happen long what are the relation with muscle fiber development and this metabolic characteristic with the increase in muscle fiber sign whether due to age selection or nutrition there is a decrease in glycogen content and these are genetic correlation this decree in glycogen content in the muscle is accompanied by an increase in the intimate pH and that's a very strong really negative relationship close to one which and this increase in ultimate pH leads to a decrease in lightness a decrease dripless and a decrease in the toughness of the meat so this is an example of what happened with selection by increasing body weight and breast meat gel so you see a player increase in the ultimate ph in this case it's not you're not coming to gfd meat so it's not a defect but still there isn't raise the edge at slaughter will also increase the ph and finally if you stimulate muscle development by nutrition for example by increasing the incorporation of lysing in the diet you get the same sort of relationship so this one comes again other metabolic changes so as mentioned before decrease in glycogen store but also a decrease in iron content with a universal yield and decrease in the oxidative activities this is linked to lower carbohydrate stores lower blood supply and lower overall oxidative activity of the muscles so blood supply is of course the result of the presence of capillaries between the muscle fibers like a chain can be detected in fibers when with the specific staining you have the fibers which have more a glycogen so what we have done in the laboratory to go further into the understanding of this the underlying mechanism is to select lines on the basis of ultimate ph though this has been done over several generation and you can see that after six generation we have ended up with a line with i you teammate ph 6.2 or low ultimate page five point seven and as you can see this is associated also with differences in color you can see that the i ph the color is darker and the low pH the paler and this animal as expected they also show a market difference in breast muscle and language and about 20% difference in the pectoralis major so we have used extensively this model to try and understand the underlying mechanism and one of the recent approach of the group has been to look at the metabolomic profile both in the muscle and in the serum of this animal and as you can see here using different approach you can see that it is possible to make the difference between the two lines whether you're looking at metabolites in the muscle this is using a different NMR approach based on proton or p31 and which a lot to distinguish 25 discriminant metabolites in the muscle and in serum by proton NMR you can refine about 20 or discriminant metabolites so you can look at metabolism the metabolic pathway which are associated with those metabolites and this is the result across all that obtained either for muscle or serum and you can see that for the annual exhibiting acidic meet you have the metabolite tells you that to meet the underlining make metabolic pathways are involving like releases Blanco neo Genesis and different [Music] sorry galactose on fructose and Manuel's metabolism also carbohydrate and nucleotide metabolism while in the dark firm on dry muscle is ultimate pH you have other metabolic pathway which are involved in protein metabolism and in oxidative metabolism so this is a summary of the different metabolites all that is described in a recent paper by book player and co-worker and as you can see this is comparing against this I low pH ultimate pH you haven't won and sorry analyte of pathway implicated in oxidative stress most muscle proteolysis sorry and antioxidant pathway in the eye pH line while you have on the other and pathways involved in energy metabolism glycolytic pathways mainly so another approach was based on transcriptomic profile conducted on the same animals you can see here that is this tell this shows either under or over expression of a number of genes and you can see that there is a very clear discrimination between the two genetic lines and the pathways which underline this differential expression are summarized here again low pH you have implicit genes involving like colitis use of carbohydrate genes involved is the control of ATP concentration amino acid metabolism muscle cell organization and other metabolism all this in linked with I energetic status and I like leakage activity this is summarized on the cartoon here by contrast in the eye pH line you have genes involving sugar transport ATP liberation synthesis of ketone bodies degradation of h2o2 degradation of phenomena muscle formation and mobility transition genes are impaired there is also indication that hyperlipidemia could be favored as well as genes involved in necrosis apoptosis and finally insulin resistance so all these points out to a low energetic statues degeneration regeneration and muscle are remodeling in this line with I pH apparel epidemia which is reminiscent of the white stripping condition which we will discuss later and increased oxidative metabolism if you look at the East illogical profile of the same animal you can see so we looked here at glycogen which is very different there is more glycogen in the low pH line consistent with what I discussed before there is also different in the expression of myosin which represents the contractile activity and also the differentiation of the muscle this is an adult male scene which expressed late in the differentiation which is expressed that which corresponds to higher glycolytic activity so it's logically expressed at higher level in the low pH line why number Yannick neonatal myosin is expressed at higher level in the other line probably because there is some regeneration same for this neonatal Miocene so in the iph line our ratio cells expressing embryonic and neonatal developmental myosin which is probably the sign of our regeneration process in conclusion on the right and again the sign of different energetic condition I like cogent on the one hand with a carbohydrate I energy on the for the other line look like a gen and increase of oxidation and catabolic processes so in summary a Chris pH ultimate pH leads to low blood supply low oxygenation low nutrient supply intensive use of institute glycogen elevated protein and muscle degradation increased oxidative stress on production of reactive oxygen species so an altered the reductionist assist so the question is we arranged a state of muscle dysfunction with alteration of fibers which in fact will be in league with the image and effect that we are going to discuss later on that also Massimiliano we talked about so this is or selective lines and this is the Defoe you've all heard of such as the white stripping the wooden breast and also an imaging defect called spongy muscles so is there a link so this is what the white stripping looks like you have this appearance of white striation and you have different degrees of severity this is accompanied with a number of perturbation at the histological level you can see here on the right normal white stripping muscles which is accompanied by muscle fiber degeneration fibrosis accumulation of connective tissue and also accumulation of lipids within the muscle if you look at higher magnification you will find some signs of muscle fiber necrosis and ATO file and macrophage infiltration in the muscle if you look at gene expression in this model you see also some markets virtual mission here is this is comparing different level white sleeping at zero level is sort of control while the level 2 is severe white stripping and in fact you would see that there are perturbation in gene involved in the regulation of cellular calcium also involved in embryonic development group here genes involved in the activation of satellite cells satellite sends our precursor within the muscle which can either be involved in normal growth or in reparation when you have need for regeneration of the muscle there is also expression of genes indicating a pathology of the connective tissue with IPA pleasure of this connective tissue and sign of lipodystrophy and finally a number of other genes involved in the development of muscles the wooden breasts sorry I did something gets wrong here well just to show you that the wooden there is difference of texture between normal on wooden breast muscle it's much harder the LTH pH is also change its iron in wooden breast muscle the lightness is ugly changed but there is an important difference in the inter redness which is considerably decreased in the wooden breast muscle suggesting a decreased blood supply and also decreased glycogen store this is an image of what you can see you can find images of necrosis development of connective tissue splitting of muscle fibres which is probably a first step before necrosis and finally images of regeneration so I'm not going to spend too much time on this because probably Massimiliano is will give further details this is a few data about gene expression in those muscles you can see here that wooden breasts is associated with the increase in embryonic myosin and the decrease in absolute to myosin which looks a bit like what I showed before and also an increase in some growth factor here igf-1 which is probably associated with proliferation and differentiation of muscle fibers also this gene may okkadine which is associated with smooth muscle formation and angiogenesis might be a marker in linked with the reduction of blood supply in this tissue so other study studies have been conducted by others a group of abashed and worker at the University of Delaware and say also identified genes differentially expressed genes associated with abnormal accumulation of intracellular calcium hypoxia increased oxidative stress switch in fiber type increased cellular repair and regeneration and finally done regulation of some genes involved in coagulation system they also made metabolomic studies and in fact what is striking is that the pathway that the identified are somehow comments with Zeus we identified when comparing were genetic lines so it seems that there is links between pH relative defects which we have identified in the lab and mustard right Rafiq syndrome which are observed in the field and I have not mentioned but that's another story oxidative damages are other important problem and all these troubles seem to be in link with muscle growth and also with energy metabolism in the muscle and they are probably determined by genetic factor but also to some extent by nutrition and rearing in conclusion genomics and metabolomics are useful to unravel meat quality determinism and identify markers for genesis purpose its highlight some common regulatory pathways underlying meat defects related to muscle growth and glycogen depletion such as bone muscle fiber vascularity which leads to decreased oxygenation of the muscle which and oxidative like resistant oxidative stress production of reactive oxygen steady us to her species increased protein an amino acid catabolism changing muscle fiber typing and increased regeneration process there are also some specific processes which are related to wooden breasts on white stripping such as necrosis which we didn't find in our selected lines an induction or cell repair processes such as the fibrosis and lipid losses which seem to sign up pseudo I can throw fear of the muscle which is reminiscent of that dystrophic dystrophy condition described in human on other species so there is a need for developing non-invasive method to identify breeders prone to development defects which could be used as genetic markers for selection also biomarkers such as blood metabolites enzyme activity or gene expression will be useful in this respect the objective will be to ensure an optimal and Avenues development of brothers with positive impact on the robustness of the animal and on mid quality we think that livestock management especially during early life should be a key period to preserve glycogen store in muscle daily differentiation to produce me off more fibers of smaller size we have seen that big fibers are detrimental and we think that maybe a better understanding of the physiology regulating the available satellite cell pool will be interesting to to ensure this proper cell growth and renewal at the expense of fibrosis and Lipa disease which is what we don't want finally it might be wise to consider using more robust strain which more ominous developments and this will probably be associated with gains in term of mortality meat waste at slaughter plants and be associated also with processing activity this is finally - thanks those who contributed at this were performing yours this is now tomorrow I thank you for your attention [Applause]