the --Inside-- Science of Nutrition

8/20/2019 . the --Inside-- Science of Nutrition

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[SOUND][MUSIC]In our livestock based food productions,an important element is howthose animals take those components,those plant based components andconvert them into products thatwe find palatable and digestible.Taking care of nutritional feeding is soimportant because itcomprises such a significant proportionof the cost of our production.And, that's true for all of our systems.But, the actual proportion variesdepending on the species anddepending on the type ofsystem under consideration.How much nutrition contributes andhow much it costs depends on those things.Dairy cattle, for instance thatare raised somewhat on pasture,nutrition might be 50to 60% of those costs.Whereas with pigs it might be 80% of

the cost of production in a swine system.But because of these costs,optimizing the nutritional content andmatching it with the productionoutcomes is an essential part ofthe management of running of an efficient,effective and profitable system.Because the costs are such a highproportion of the total costs that gointo an animal.And nutrition feeding an animal isn't justsimply turning them out onto a pasture orputting feed in front of them.

Nutrition is a complex scientific process.Feeding the animals exactlythe right constituents atexactly the right time is really importantfor the sustainability of production.And to understand nutrition, to be ableto design good nutritional programs,you need to be able to understand notjust the components of the nutrition,not just what the components ofplants are and how they're made up.But also the anatomy andphysiology of the animal.

How their intestinal tract works,how they digest nutrients,how they maximize those tobecome efficient in production.So I'm Dr. Brian Aldrich, I'm here atthe College of Veterinary Medicine atthe University of Illinois, andwe're in the Department of Anatomy.And to start to understand thatscience of how nutrition works.



We're going inside of a cow.This is a skeleton of an adult cow usedhere as an autonomy demonstration to teachthe Bentley students the structures thatare inherit to the function of this animaland we want to just show you where themajor part of the digestive system sits.For ruminants, they're unique because theyhave four compartments to their stomach.And within their abdomen they have amassive fermentation vac called the rumen.That's the second of the stomachs andit sits right here withinthe belly of the animal.And all of the otherstructures are secondary toreally this Rumen inthe digestive process.The Rumen lining has smalllittle Little leaves,tiny little microscopic leaves whichincrease the surface air of the room and,and therefore optimizeits absorptive capacity.

Absorbing the break down productsof the bacterial fermentation,particular the break down productsof carbohydrate metabolism.The volatile.Fatty acids.And that is the seat of efficiency fornutrition and the seat of efficiency forproduction as far asnutrition is concerned.So here I am holding the four stomachs ofa ruminant inside the abdomen of this cow.So that's exactly where it sits.

But if you think that this is the realstructure and this is the real size,I'm fooling you because thisis actually a sheep's stomach.And it's about a tenth of the size of thatwhich would sit inside this cow's abdomen.Now this is the real rumen of this animal.And as you can see it's massive.It's a massive fermentation vat.Probably all together thisstructure holds something like300 liters, 300 liters of fluid.Each compartment structurally designed

both in its form and its function.To most efficiently takeundigestible proteins andcarbohydrates and make them digestible.Firstly for the animal, and then toconvert them into metabolic products.So let me talk you around the differentstomachs in this specimen.The rumen is unique inthat it has four stomachs.



This here is the first stomach,it's called the reticulum.The reticulum is in some ways the firstcompartment that the food meets.The food comes down the esophagus,down the throat and through a smallsphincter here and is then dumpedinto this part of the stomach.It's lined with a reticulated mucosawhich is designed to capture particles.And it's so effective, that, if the animalswallows a, a piece of wire, to preventthe wire from accessing lower parts ofthe intestine, they get trapped there.Stones will get trapped inthis honeycomb appearance,stopping it's interference withother digestive processes.And every part of this remarkable stomachsystem is unique in structure, butalso in lining, and also in its contents.Each of them, though contiguous,perform a different function,because of their anatomical structure.

But this is also, the part of the stomach,when the food is chewed again and again.This is the food that goesback up into the mouth soa doesn't just chew it's food once,it takes in the food,it goes down into the andthen it's brought back up and down sothat this plant material is, is, in stepwide fashion is crushed and broken up.Now this occurs by a repeatedprocess of chewing.Of, of swallowing, of entry into the room

and vat and then of bringing it back up.So this is where rumination takes place,this is also the first sackof this fermentation vat andfood moves from this structureinto this large multi-sacked.Parts of the stomach called the rumen.This is where allthe fermentation takes place.Again, it has a unique structure ofsacks cause that's where most ofthe mixing takes place.It is mixed up so that the bacteria are

exposed to every part of that digester.And there's three layers of food,in this rumen.There's the top layer, which is the gas,which is a byproduct of digestion.There's a fiber layer that sits in there.And that's the part of the fiber thatgoes into the reticulum and is rechewed.It's the long fiber.And then, the bottom, there's food



particles suspended in liquid.Looks more like pea soup.And that's where,the bacteria doing most of their work.Being exposed to the small fibres anddoing the digestion.Taking the plant proteins andthe complex carbohydrates andbreaking them down into simplerproteins and simpler sugars as well.Probably about one point five billionbacteria live in that, in the animal.From there, as the food is broken down,the more liquid component goesthrough another sphincter,another opening, into this omasum.And every stage, every stage of digestion,the particles are going fromlong fibers to smaller fibers.And when it gets to there it'sessentially smaller particles witha large amount of fluid.But to get down into the smaller partsof the intestine in the lower parts of

the intestinal tract,most of the water should be removed.And that's what takesplace in this omasum.The lining of the omasum like book leaves.And it's a perfect way to increasethe surface area such as, sothat water absorption could be maximized.And that's where a lot ofthe water is absorbed.From there, the food goes intowhat is really the true stomach,the abomasum, the stomach that in

humans and in pigs and in horsesdoes most of the digestive processesof the gastric part of the intestine.It's the true stomach because that's wheresome of the enzymes are produced thatdigest some of the carbohydrates andthe proteins.The lining of the abomasum is glandular.It's full of folds, butit's secretory, the only part of thesefour stomachs that secrete anything.It secretes the digestive enzymes.It secretes the hydrochloric

acid to lower the pH.It's a true stomach because.Its acidity, its PH, is much lowerthan the rest of the intestinal tract.The secretion that comes out of the liningof this is called hydrochloric acid.As with humans, andas with other monogastrics.So, the components of this part ofthe digestive tract have been simplified.



From the long fiber thatwe've seen in the rumen.And, the bacteria in the rumenhave done most of the digestion.They've been breaking down the cellulosesand the starches to more simple sugars.They've been takingthe protein in those plants andbreaking them down totheir essential acids.In fact,the bacteria then take the amino acids andput them into the proteinof their own body wall.And they form part of the nutrients forthe lower digestive tract.The abomasum's role and the lowerintestine is to take those bacteria andbreak them down and to releasethe nutrients that they have released fromthe grasses and the grains that tookplace during the fermentation process.So in some way forthe ruminant, the bacteria become

an important dietary component.The bacteria break down the,the plants andthen the rest of the bodydigests the bacteria.But these things thatwe do nutritionally andmanagely, managementally which are fake,the structure and function.The contents of these rumen.If we don't get the nutrition right,if you don't get the nutrition right,then we mess up the function of this

wonderful organ, and therefore.We decreased productivity.[MUSIC]

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the --Inside-- Science of Nutrition