Glycerol till mjölkkor : effekter på våmmetabolismen
Glycerol is essential for the lipid metabolism of both plants and animals. Glycerol is formed in the rumen by hydrolysis of lipids from the feed. Glycerol is also a by-product from the production of biodiesel from rapeseed oil and other fat sources. Glycerol might be used as a dietary glucose precur...
| Autor principal: | |
|---|---|
| Formato: | L3 |
| Lenguaje: | sueco Inglés |
| Publicado: |
SLU/Dept. of Animal Nutrition and Management (until 231231)
2008
|
| Materias: |
| _version_ | 1855571995841789952 |
|---|---|
| author | Kullberg, Karin |
| author_browse | Kullberg, Karin |
| author_facet | Kullberg, Karin |
| author_sort | Kullberg, Karin |
| collection | Epsilon Archive for Student Projects |
| description | Glycerol is essential for the lipid metabolism of both plants and animals. Glycerol is formed in the rumen by hydrolysis of lipids from the feed. Glycerol is also a by-product from the production of biodiesel from rapeseed oil and other fat sources. Glycerol might be used as a dietary glucose precursor for dairy cows in similar ways as propylene glycol. Due to increased production of biodiesel more glycerol has been available to a lower price. There are different qualities of glycerol on the market representing different stages of processing. Crude glycerol also contains water, fat, minerals and methanol while refined glycerol often contains >99.5% glycerol.
This study was divided in two different parts. In the first part three rumen fistulated non-lactating, nonpregnant cows were used. Fractional disappearance of glycerol from the rumen was determined by means of a combination of in vivo and in vitro methods. Furthermore the effects of glycerol on rumen fluid volatile fatty acids (VFA) concentration and osmolality were analysed. In the second part four rumen fistulated lactating cows received two different glycerol qualities or as a control no glycerol during three two week periods. The effect of the two glycerol qualities on digestibility of dry matter (DM), neutral detergent fiber (NDF) and crude protein CP) was determined. Furthermore the effect of the different glycerol qualities on rumen fluid VFA concentration and osmolality was investigated.
Glycerol appeared to be readily absorbed from the rumen and while the digestion rate of glycerol in the rumen was low. The rumen micro flora apparently did not adapt to glycerol since the rate of glycerol digestion was not affected when the coes were fed glycerol for two weeks. Glycerol did not have any marked effect on the digestibility of silage DM, NDF or CP. Glycerol changed the rumen fluid VFA pattern towards more butyrate and less acetate while the effect on propionate varied. The total concentration of VFA rumen fluid was reduced by glycerol. There appeared to be no difference between the two glycerol qualities regarding rumen metabolism. |
| format | L3 |
| id | RepoSLU12079 |
| institution | Swedish University of Agricultural Sciences |
| language | swe Inglés |
| publishDate | 2008 |
| publishDateSort | 2008 |
| publisher | SLU/Dept. of Animal Nutrition and Management (until 231231) |
| publisherStr | SLU/Dept. of Animal Nutrition and Management (until 231231) |
| record_format | eprints |
| spelling | RepoSLU120792017-11-08T09:13:17Z Glycerol till mjölkkor : effekter på våmmetabolismen Glycerol to dairy cows : effects on the rumen metabolism Kullberg, Karin glycerol mjölkkor våmmetabolism Glycerol is essential for the lipid metabolism of both plants and animals. Glycerol is formed in the rumen by hydrolysis of lipids from the feed. Glycerol is also a by-product from the production of biodiesel from rapeseed oil and other fat sources. Glycerol might be used as a dietary glucose precursor for dairy cows in similar ways as propylene glycol. Due to increased production of biodiesel more glycerol has been available to a lower price. There are different qualities of glycerol on the market representing different stages of processing. Crude glycerol also contains water, fat, minerals and methanol while refined glycerol often contains >99.5% glycerol. This study was divided in two different parts. In the first part three rumen fistulated non-lactating, nonpregnant cows were used. Fractional disappearance of glycerol from the rumen was determined by means of a combination of in vivo and in vitro methods. Furthermore the effects of glycerol on rumen fluid volatile fatty acids (VFA) concentration and osmolality were analysed. In the second part four rumen fistulated lactating cows received two different glycerol qualities or as a control no glycerol during three two week periods. The effect of the two glycerol qualities on digestibility of dry matter (DM), neutral detergent fiber (NDF) and crude protein CP) was determined. Furthermore the effect of the different glycerol qualities on rumen fluid VFA concentration and osmolality was investigated. Glycerol appeared to be readily absorbed from the rumen and while the digestion rate of glycerol in the rumen was low. The rumen micro flora apparently did not adapt to glycerol since the rate of glycerol digestion was not affected when the coes were fed glycerol for two weeks. Glycerol did not have any marked effect on the digestibility of silage DM, NDF or CP. Glycerol changed the rumen fluid VFA pattern towards more butyrate and less acetate while the effect on propionate varied. The total concentration of VFA rumen fluid was reduced by glycerol. There appeared to be no difference between the two glycerol qualities regarding rumen metabolism. Glycerol är ett livsnödvändigt ämne som behövs för att växter och djur ska kunna bilda fett. Glycerol frigörs i våmmen vid mikrobiell hydrolys av växtlipider och andra oljor och fetter som tillförts genom fodret (Paggi et al., 1999; 2004). Glycerol bildas även som restprodukt vid framställning av biodiesel och kan användas som fodertillskott till mjölkkor eller vid behandling av så kallad acetonemi. Acetonemi kan uppstå till följd av en negativ energibalans främst vid tiden efter kalvning och glycerol kan användas för behandling av detta på liknande sätt som andra glukogena substrat som exempelvis propylenglykol. (Rémond et al., 1992; DeFrain et al., 2004; Schröder et al., 1999). Den glycerol som bildas som restprodukt vid framställning av biodiesel är inte helt ren utan innehåller bland annat vatten, oljor, salter och metanol. Dessa ämnen försvinner nästan fullständigt om glycerolfraktionen raffineras. Tillskott av glycerol har visat sig kunna förändra VFA sammansättningen i våmmen genom att acetatproportionen minskar medan propionat, och butyrat ökar (Reichel et al., 2004; DeFrain et al., 2004; Rémond et al., 1992; Schröder et al., 1999). Südekum (2007) registrerade endast en minskning av acetat och en ökning av propionat. I vissa studier har man funnit att glycerol minskar foderintaget medan studier visar att glycerol inte påverkar foderintaget (Bodarski et al., 2005; Reichel et al., 2004; Ogborn et al., 2004; DeFrain et al., 2004). Glycerol kan ombildas till glukos via glukoneogenesen i levern och kan därmed öka andelen tillgänglig glukos för den högproducerande mjölkkon som annars lätt drabbas av glukosbrist (Sjaastad et al., 2003). Mitt examensarbete bestod av två delmoment. Syftet med det första delmomentet var främst att se hur stor andel glycerol som omsätts av mikroorganismerna i våmmen och hur stor del som resorberas från våmmen. Under moment två var ett av syftena att se om det finns en tillvänjning för våmmikroberna som gör det lättare för dem att efter en tid omsätta glycerol. Vidare syftade studien till att undersöka hur smältbarheten av fodrets torrsubstans, fiber- och råproteinfraktion påverkas vid tillsats av rå- respektive raffinerad glycerol. En annan målsättning var att undersöka hur glycerol, såväl rå- som raffinerad, påverkar VFA sammansättningen i våmvätskan. SLU/Dept. of Animal Nutrition and Management (until 231231) 2008 L3 swe eng https://stud.epsilon.slu.se/12079/ |
| spellingShingle | glycerol mjölkkor våmmetabolism Kullberg, Karin Glycerol till mjölkkor : effekter på våmmetabolismen |
| title | Glycerol till mjölkkor : effekter på våmmetabolismen |
| title_full | Glycerol till mjölkkor : effekter på våmmetabolismen |
| title_fullStr | Glycerol till mjölkkor : effekter på våmmetabolismen |
| title_full_unstemmed | Glycerol till mjölkkor : effekter på våmmetabolismen |
| title_short | Glycerol till mjölkkor : effekter på våmmetabolismen |
| title_sort | glycerol till mjölkkor : effekter på våmmetabolismen |
| topic | glycerol mjölkkor våmmetabolism |