Yliopiston etusivulle Suomeksi På svenska In English Helsingin yliopisto

Effects of parturition, feed energy and fibre contents to the expression of lipogenic and lipolytic genes in dairy cows

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dc.contributor Helsingin yliopisto, Maatalous-metsätieteellinen tiedekunta, Maataloustieteiden laitos fi
dc.contributor.author Sekhar, Deepa
dc.date.accessioned 2012-11-28T09:41:30Z
dc.date.available 2012-11-28T09:41:30Z
dc.date.issued 2012-11-28
dc.identifier.uri http://hdl.handle.net/10138/37658
dc.description.abstract Metabolic disorders are known to predispose dairy cows to periparturient diseases. Main components of metabolic disorder are insulin resistance and severe negative energy balance which are responsible for the reduced fertility in addition of increased risk of disease in dairy cows. The mobilization of adipose tissue in response to energy deficiency is associated with metabolic and endocrine changes during early lactation. Reduced insulin sensitivity in peripheral tissues could potentially change the relative rates of lipolysis and lipogenesis. This study focused on expression of lipogenesis and lipolysis associated genes around parturition. Samples and data sets for this study were obtained from the feeding experiments conducted from September 2010 to April 2011 in Viikki Experimental Farm at the University of Helsinki. Sixteen multiparous Ayrshire cows were divided into two groups based on energy level and fibre content of their feed: (1) grass silage group (control) and (2) silage-roughage mixture group (experiment). During experimental period average energy intake (MJ/day) in silage group was 35% higher than in silage-roughage mixture group. Subcutaneous adipose tissue samples were collected a week before, one day and a week after parturition from cows. Total RNA was extracted from tissue samples quality and quantity of total RNA was analysed using electrophoresis and spectrophotometer. Complementary DNA (cDNA) was prepared from the total RNA for quantitative PCR (qPCR). QPCR was conducted to quantitate expression of the following genes: adiponectin (ADIPOQ), leptin (LEP), peroksisome proliferator activated receptor gamma (PPAR-γ), adiponectin receptor-1 (AR1), adiponectin receptor-2 (AR2), lipoprotein lipase (LPL), stearoyl-CoA desaturase (SCD) and hormone-sensitive lipase (HSL). Two genes, AR2 and LEP, were downregulated in group 1. Reduced expression of AR2 in group 1 may relate to an increased insulin resistance. The glucose metabolism was reduced further leading to reduced insulin sensitivity. Lower expression of LEP after parturition indicates usage of energy for milk production. The upregulation of SCD in group 1 before and after calving as well as after calving in group 2 may be a result of the uptake of fatty acids by the mammary tissues. The expression of ADIPOQ, AR1, LPL, PPAR, and HSL did not show any significant changes. fi
dc.language.iso en fi
dc.subject opinnäytteet fi
dc.subject pro gradu-tutkielmat fi
dc.subject severe negative energy balance
dc.subject adipose tissue
dc.subject lipogenesis
dc.subject lipolysis
dc.subject insulin resistance
dc.subject parturition
dc.subject dairy cows
dc.title Effects of parturition, feed energy and fibre contents to the expression of lipogenic and lipolytic genes in dairy cows fi
dc.type.ontasot Pro gradu -työ fi
dc.ths Elo, Kari
dc.subject.discipline Biotekniikka fi
dc.subject.discipline MBIOT, Master’s degree Programme in Biotechnology

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