Manipulation of the rumen environment to increase rumen undegradable protein fraction of feedstuffs

Date
2024-03
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Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: The digestive tract of ruminants follows the order of rumen, reticulum, omasum and abomasum, where at least 50 % or more of the total digestion of feed intake occurs. Digestion of protein is a broad spectrum explained by the nitrogen metabolism pathways of any ruminant; dietary protein consumed by a ruminant can split into rumen-degradable and undegradable protein. The rumen itself produces protein for use, in the form of ammonia nitrogen, endogenous nitrogen and microbial protein. Thus, when rumen degradable protein is found to be in excess, the protein will be lost through urine, as urea will be metabolized in the liver. The loss of protein or nitrogen due to excess ammonia can thus be an extreme expenditure and methods to minimize the loss and the cost of feeding protein are greatly researched. These losses whether it be for maintenance or production purposes in ruminants can be compensated or overcome if methods are used to increase the undegradable proteins. Meaning one can reduce the feeding of protein to improve production without diminishing the protein needs of the animal. Methods of protecting feedstuff have shown results to increase rumen undegradable proteins (RUP) for example encapsulation, extrusion, or formaldehyde treatment of feeds. These methods of protecting proteins or increasing the availability thereof still have to be modified into the diet itself, thus extra cost put in processing the feed to achieve this increased availability of RUP. The aim of this study will be to manipulate the rumen fermentation, ruminal pH and/or microbes to provide potentially improved protein availability for use to the animal, without the modification of the feed. The inclusion of tannins (Farmatan D®- 0 %, 0.25 %, 0.5 %, 0.75 %, 1 %), lipids (plant oil extracts- 0 %, 1.25, 2.5 %, 3.75 %, 5 %) and sodium bicarbonate (sodium bicarbonate- 0 %, 0.75 %, 1.5 %, 2.25 %, 3.0 %) were incorporated into the diet for five cannulated sheep, each receiving its own inclusion. Tannins in the past were only to be seen as detrimental to the animal, but with further studies have shown it involves the type of tannins used namely condensed tannins that has this effect. The other type of tannins, which are hydrolysable, have been shown to decrease urinary nitrogen loss and have abilities to manipulate the rumen and bind to microbial protein that can lead to greater availability of protein for use. The inclusion of lipids, especially higher inclusion thereof has led to fibre coating in the rumen, which resulted in a manipulation of the rumen itself, potentially increasing the RUP. Lastly the inclusion of the sodium bicarbonate was incorporated into the diet, with emphasis on a high grain diet to decrease the pH of the rumen to gain greater results when used. The inclusion of sodium bicarbonate increased the pH with the increasing inclusions in the diet. The high grain fed diet with each respective inclusion, was used to determine (using in vitro) the potential protein degradation and fractional rate of digestion due to the manipulation of the rumen. The optimum inclusion for tannins, lipids and sodium bicarbonate were determined, after each in vitro study was completed. This study will be especially beneficial for further research of the tannins used and determining the RUP available after in vitro trials. The inclusion of all three these supplementations to the diet manipulated did not show desired results in the manipulation of the rumen degradation. Even with the maximum inclusion of Farmatan D® and lipids in the diet, as theorized could lead to great protein availability, did not occur. Whereas the maximum inclusion of sodium bicarbonate did not have optimum availability of proteins, and did not show any significant results. This was determined by using in vitro methods for protein degradation and fractional rate of digestion for all the respective inclusion levels of the three supplementations, did not lead to rumen degradation.
AFRIKAANSE OPSOMMING: Die spysverteringskanaal van herkouers volg die volgorde van rumen, retikulum, omasum en abomasum, waar ten minste 50 % of meer van die totale vertering van voedselinname plaasvind. Die vertering van proteïene is 'n breë spektrum wat verduidelik kan word deur die stikstofmetabolisme paaie van enige herkouer; dieetproteïene wat deur 'n herkouer verbruik word, kan verdeel word in rumen-afbreekbare en onafbreekbare proteïen. Die rumenproduseer proteïen vir gebruik, in die vorm van ammoniakstikstof, endogene stikstof en mikrobiese proteïen. Dus, wanneer rumen-afbreekbare proteïen in oormaat gevind word, sal die proteïen verlore gaan deur urine, aangesien ureum in die lewer gemetaboliseer sal word. Die verlies van proteïene of stikstof, as gevolg van oormaat ammoniak kan dus 'n groet invloed wees op die dier en die dier se produksie. Dus, word metodes om die verlies en die koste van voedingsproteïen te verminder, intensief nagevors. Hierdie verliese, of dit nou vir instandhouding of produksiedoeleindes in herkouers is, kan oorkom word deur hulp van metodes om die onafbreekbare proteïene te verhoog. Dit beteken dat 'n mens die voeding van proteïene kan verminder om produksie te verbeter sonder om die proteïenbehoeftes van die dier te verminder. Metodes om voer te beskerm het resultate verkry deur rumen onafbreekbare proteïene (RUP) te verhoog, byvoorbeeld inkapseling, ekstrusie, of formaldehiedbehandeling van voere. Hierdie metodes om proteïene te beskerm of die beskikbaarheid daarvan te verhoog, moet nog steeds in die dieet self aangepas word, dus ekstra koste word benodig in die verwerking van die voer om hierdie verhoogde beskikbaarheid van RUP te bereik. Die doel van hierdie studie sal wees om die rumenfermentasie, rumenale pH en/of mikrobes te manipuleer om potensieel verbeterde proteïenbeskikbaarheid vir die dier beskikbaar te maak, sonder enige ekstreme modifikasie aan die voer te maak nie. Die insluiting van tanniene (Farmatan D®- 0 %, 0.25 %, 0.5 %, 0.75 %, 1 %), lipiede (plantaardige olie-ekstrakte-0 %, 1.25 %, 2.5 %, 3.75 %, 5 %) en natriumbikarbonaat (natriumbikarbonaat- 0%, 0.75 %, 1.5 %, 2.25 %, 3.0 %) is in die dieet van vyf gekannuleerde skape ingesluit, elkeen met sy eie insluiting. Tanniene is in die verlede slegs gesien as nadelig vir die dier, maar verdere studies het getoon dit behels die tipe tanniene wat gebruik word, naamlik gekondenseerde tanniene wat hierdie negatiwe effek het. Die ander tipe tanniene, wat hidroliseerbaar is, het vindings getoon wat urinêre stikstofverlies te verminder het, en het dus die vermoë om die rumen te manipuleer. Wat die mikrobiese proteïenbindings kan lei tot groter beskikbaarheid van proteïen vir gebruik. Die insluiting van lipiede, veral hoër insluiting daarvan, het gelei tot veselbedekking in die rumen, wat manipulasie van die rumen self veroorsaak, en dus potensieel die RUP verhoog het. Laastens, is die insluiting van die natriumbikarbonaat in die dieet ingesluit, met klem op 'n hoë graan dieet om die pH van die rumen te verlaag om groter resultate te verkry wanneer gebruik, soos wat diere normaalweg in voerkrale gevoer word. Die insluiting van natriumbikarbonaat het die pH verhoog met die toenemende insluitings in die dieet. Die hoë graan dieet met elke onderskeie insluiting, is gebruik om (met behulp van in vitro) die potensiële proteïenafbraak en fraksionele verteringskoers te affekteer deur die manipulasie van die rumen te bepaal. Die optimale insluiting vir tanniene, lipiede en natriumbikarbonaat is bepaal, nadat elke in vitro studie voltooi is. Hierdie studie sal veral voordelig wees vir verdere navorsing van die tanniene wat gebruik word en om die “RUP” beskikbaar na in vitro toetse te bepaal. Die insluiting van al drie hierdie aanvullings in die dieet het nie die gewenste resultate in die manipulasie van rumen-afbraak getoon nie. Selfs met die maksimum insluiting van Farmatan D® en lipiede in die dieet, wat teoreties tot 'n hoë beskikbaarheid van proteïene sou lei, het dit nie tot einge betekenisvolle resultate gelei nie. Terwyl die maksimum insluiting van natriumbikarbonaat nie optimale beskikbaarheid van proteïene gehad het nie, het gelei tot geen betekenisvolle resultate. Dit is vasgestel deur in vitro-metodes vir proteïenafbraak en fraksionele verteringskoers vir al die onderskeie insluitingsvlakke van die drie aanvullings te gebruik, het gelei tot geen rumenmanipulasie.
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Thesis (MScAgric)--Stellenbosch University, 2024.
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