Laktatsioonijärgu ja lehma poegimiseelse toitumushinde mõju piimarasva rasvhappelisele profiilile
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Kuupäev
2015
Kättesaadavus
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Käesolev magistritöö on osa institutsionaalsest uurimisprojektist (IUT8-1) ,,Piimalehmade
sigimine ja tervis“.
Magistritöö ülesanneteks oli anda kirjanduse põhjal ülevaade piimarasvas leiduvatest
rasvhapetest ja nende päritolust ning selgitada laktatsioonijärgu ja lehmade poegimiseelse
toitumishinde mõju piimarasva rasvhappelisele profiilile. Katse käigus koguti piimaproovid
Eerika Farm OÜ laudas viieteistkümnelt katselehmalt alates seitsmendast poegimisjärgsest
lüpsist kuni laktatsiooni lõpuni. Toitumushinde alusel jaotati lehmad kolme rühma: esimesel
rühmal oli toitumushinne ≤3,0 palli, teisel 3,25-3,5 palli ning kolmandal rühmal ≥3,75 palli.
Piimaproovidest määrati piimarasva rasvhappeline koostis ning rasvhapete osakaalud Eesti
Maaülikooli piima kvaliteedi uurimise laboris.
Uurimustöö käigus leiti, et laktatsiooniperiood mõjutas oluliselt enamiku rasvhapete osakaalu
piimarasva rasvhapetes ning suurimad muutused piimarasva rasvhappelises profiilis toimusid
laktatsiooni 1.-12. nädalani. De novo sünteesitud rasvhapete osakaal piimarasvas suurenes
kuni 12. laktatsiooninädalani ning seejärel stabiliseerus. Ka enamiku vatsamikroobidest
pärinevate hargnenud ja paarituarvulise süsinikahelaga rasvhapete osakaalud piimarasva
rasvhapetes suurenesid laktatsiooni jooksul, seejuures olid muutused suuremad laktatsiooni
alguses. Rasvkoest pärinevate rasvhapete osakaal oli laktatsiooniperioodi alguses suurem kui
oli laktatsiooni edenedes.
Lehmade poegimiseelne toitumushinne mõjutas oluliselt piimarasva rasvhappelist profiili - de
novo sünteesitud rasvhapete osakaal oli laktatsiooni kümnendal nädalal väikseim (23,0 g/100
g rasvhapetes) suurima poegimiseelse toitumushindega (BCS3,75) lehmade piimarasva
rasvhapetes. Alates laktatsiooni kümnendast nädalast oli monoküllastamata rasvhapete
osakaal suurim (32,0-25,5 g/100 g rasvhapetes) suurima poegimiseelse toitumushindega
(BCS3,75) lehmade piimarasva rasvhapetes. Laktatsiooni esimesel nädalal oli hargenud
ahelaga rasvhapete osakaal suurim (1,60 g/100 g rasvhapetes) madalaima toitumushindega
(BCS≤3,0) lehmade piimarasva rasvhapetes.
The master’s thesis is a part of the institutional research project (IUT8-1) „Fertility and health of dairy cattle“. The objective of the thesis was to give an overview of the literature on milk fat fatty acids and their origin and to explain the effect of lactation stage and body condition score (BCS) at drying off on the milk fatty acid profile. Milk samples for fatty acid analyses were collected throughout lactation from 15 cows at Eerika Farm OÜ. Cows were divided into three groups according to their body condition score at drying off: first group BCS ≤3,0, second group BCS 3,25-3,5 and third group BCS≥3,75. The milk fatty acid profile was analysed using gas chromatograph in the Laboratory of Milk Quality at the Estonian University of Life Science. The lactation period affected the proportion of most fatty acids in milk fat and most noticeable changes took place between the 1 st and 12th week of lactation. The proportion of de novo synthesized fatty acids increased until the week 12 of the lactation and then stabilized. The proportions of most odd- and branched-chain fatty acids in milk fat increased during lactation and the increase was more distinct in early lactation. The proportions of fatty acids originating from adipose tissue were higher at the beginning of lactation. The body condition score of the cows at drying off significantly affected the fatty acid profile of the milk fat. The proportion of the sum of de novo synthesized fatty acids in week 10 of lactation was the smallest (23,0 g/100 g fatty acids) in cows with the highest body condition score (BCS3,75) Starting from the 10th week of lactation the proportion of the sum of monounsaturated fatty acids was the biggest (32,0-25,5 g/100 g fatty acids) in cows with the highest body condition score (BCS3,75). At the first week of lactation, the proportion of the sum of odd- and branched-chain fatty acids was the biggest (1,60 g/100 g fatty acid) in cows with the smallest body condition score (BCS≤3,0).
The master’s thesis is a part of the institutional research project (IUT8-1) „Fertility and health of dairy cattle“. The objective of the thesis was to give an overview of the literature on milk fat fatty acids and their origin and to explain the effect of lactation stage and body condition score (BCS) at drying off on the milk fatty acid profile. Milk samples for fatty acid analyses were collected throughout lactation from 15 cows at Eerika Farm OÜ. Cows were divided into three groups according to their body condition score at drying off: first group BCS ≤3,0, second group BCS 3,25-3,5 and third group BCS≥3,75. The milk fatty acid profile was analysed using gas chromatograph in the Laboratory of Milk Quality at the Estonian University of Life Science. The lactation period affected the proportion of most fatty acids in milk fat and most noticeable changes took place between the 1 st and 12th week of lactation. The proportion of de novo synthesized fatty acids increased until the week 12 of the lactation and then stabilized. The proportions of most odd- and branched-chain fatty acids in milk fat increased during lactation and the increase was more distinct in early lactation. The proportions of fatty acids originating from adipose tissue were higher at the beginning of lactation. The body condition score of the cows at drying off significantly affected the fatty acid profile of the milk fat. The proportion of the sum of de novo synthesized fatty acids in week 10 of lactation was the smallest (23,0 g/100 g fatty acids) in cows with the highest body condition score (BCS3,75) Starting from the 10th week of lactation the proportion of the sum of monounsaturated fatty acids was the biggest (32,0-25,5 g/100 g fatty acids) in cows with the highest body condition score (BCS3,75). At the first week of lactation, the proportion of the sum of odd- and branched-chain fatty acids was the biggest (1,60 g/100 g fatty acid) in cows with the smallest body condition score (BCS≤3,0).
Kirjeldus
Märksõnad
laktatsioon, lehmad, toitumus, piimarasvad, rasvhapped, magistritööd