Conjugated linoleic acid-induced milk fat reduction associated with depressed expression of lipogenic genes in lactating Holstein mammary glands

Abstract

ABSTRACT. The efficacy of conjugated linoleic acid (CLA) in diet supplements for milk fat reduction is well documented in several species. However, the mechanisms by which fatty acids regulate mammary lipogenesis remain largely unknown, especially with regard to gene expression of enzyme and regulators. In this study, 8 Holstein dairy cows in their mid-lactation period were randomly divided into 2 groups. Control cows received a Ca salt of palm oil fatty acid dietary supplement, and those in the CLA group were fed Ca salts of CLA (Ca-CLA), all in a dose of approximately 200 g•cow -1•day -1 for 14 days. The milk yield was recorded daily, and protein, lactose, and fat in the milk were quantified every 3 4755 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (4): 4754-4764 (2012) CLA reduces lipogenic gene expression days for 2 weeks. Fatty acids in the milk were analyzed with gas-liquid chromatography. Measurement of messenger RNA levels of the main lipogenic genes of lipoprotein lipase, acetyl-coenzyme A (CoA) carboxylase, fatty acid synthase, stearoyl-CoA desaturase, and transcription factors such as sterol response element binding protein 1 (SREBP1) and peroxisome proliferator-activated receptor γ was performed in biopsy samples of mammary tissue on the last day. The results indicated that dietary Ca-CLA caused a continuous reduction of milk fat (P < 0.01) with no effect on milk yield, milk protein, and lactose. The fatty acid profile in the milk from the CLA group differed from that from controls, and the yield of milk fatty acid decreased (P < 0.01) with Ca-CLA supplementation. The depressed expression of lipogenic genes (lipoprotein lipase, acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase) demonstrated inhibition of fatty acid de novo synthesis and uptake in the mammary gland of the CLA group. Furthermore, the gene expression of transcription factor SREBP1 was also downregulated (P < 0.01), but peroxisome proliferator-activated receptor γ was unchanged, suggesting that SREBP1 may play a key role in the regulation of lipogenic gene expression in the lactating mammary gland.

The effect of polymorphism in the &lt;i&gt;FADS2&lt;/i&gt; gene on the fatty acid composition of bovine milk

“…The fatty acid composition in the milk samples of cows in the present study corresponded with the results obtained for dairy breeds. The most represented group of FAs in milk was SFA, followed by monounsaturated fatty acid (MUFA) and PUFA, which is consistent with the previous results (Carvajal et al, 2016;Hanuš et al, 2016;Vranković et al, 2017). Vranković et al (2017) showed a similar FA composition in the milk of Holstein cows (C10:0 = 3.053, C12:0 = 3.694, C14:0 = 12.33 vs. C10:0 = 3.00, C12:0 = 3.70, C14:0 = 12.03) at the 150th day of lactation.…”

“…The feeding of dairy cows is the main factor impacting milk fat composition. Pasture intake reduces the concentration of saturated fatty acids (SFAs) in the milk of grazing cows (Couvreur et al, 2007;Frigo et al, 2015;Hanuš et al, 2016;Ponnampalamet al, 2018). Furthermore, genetic factors influence fatty acid (FA) variability.…”

Short communication: A decrease in diameter of milk fat globules accompanies milk fat depression induced by conjugated linoleic acid supplementation in lactating dairy cows

“…We hypothesized that reduction of milk fat in response to feeding CLA is associated with altered MFG size. We used a rumen-protected product rich in trans-10,cis-12 CLA (Han et al, 2012) to induce MFD and measured MFG size using a laser particle size analyzer.…”

Doestrans-10,cis-12 conjugated linoleic acid affect the intermediary glucose and energy expenditure of dairy cows due to repartitioning of milk component synthesis?

“…Other studies were also considered but not included in the evaluation because they did not satisfy one or more of the criteria: Bell & Kennelly (2003), Hutchinson et al (2012), Moallem et al (2010) and Piperova et al (2004) reported milk FA concentrations only for FA of between 14 and 18, 12 and 22, 12 and 20, and 14 and 20 carbon atoms, respectively;Loor & Herbein (2003) only infused CLA for 48 h and collected milk samples directly after infusion had stopped;Viswanadha et al (2003) applied CLA intravenously;Moore et al (2005) investigated the effects of CLA on heat-stressed cows;Hun et al (2012) did not report the DMI of the animals and Pappritz et al (2011) reported pooled milk FA concentrations and DMI which was not recorded simultaneously with milk samples for FA analyses such that milk FA composition could not be related to DMI.Hötger et al (2013) did not report the total milk fat yield of the animals;Huang et al (2008) did not report how much trans -10, cis -12 CLA was administered to the cows; andMedeiros et al (2010) used crossbred Holstein x Zebu cows, Shingfield et al (2009) used Finnish Ayrshire cows and Sigl et al (2010) used Brown Swiss cows instead of Holstein cows and thus, dietary effects on milk component synthesis might be overlaid or masked by inter-breed differences (Stoop et al 2008). …”

“…Hun et al (2012) did not report the DMI of the animals and Pappritz et al (2011) reported pooled milk FA concentrations and DMI which was not recorded simultaneously with milk samples for FA analyses such that milk FA composition could not be related to DMI.…”