Trans-10,cis-12 conjugated linoleic acid reduces milk fat content and lipogenic gene expression in the mammary gland of sows without altering litter performance

Abstract

Trans-10, cis-12 conjugated linoleic acid (CLA) decreases milk fat synthesis in lactating sows and involves, at least in part, the down-regulation of lipogenic genes. The objective was to evaluate the effect of CLA on milk composition and lipogenic gene expression. Twenty multiparous sows were randomly assigned to one of the two treatments for 18 d (from day 7 to day 25 of lactation): (1) control (no CLA added) and (2) 1 % of CLA mixed into the ration. CLA treatment decreased milk fat and protein content by 20 % (P = 0·004) and 11 % (P = 0·0001), respectively. However, piglet weight did not differ between treatments (P = 0·60). Dietary CLA increased the concentration of SFA in milk fat by 16 % (P < 0·0001) and decreased MUFA by 17·6 % (P < 0·0001). In the mammary gland, CLA reduced gene expression of acetyl-CoA carboxylase-α by 37 % (P = 0·003), fatty acid synthase by 64 % (P = 0·002), stearoyl-CoA desaturase 1 by 52 % (P = 0·003), lipoprotein lipase by 26 % (P = 0·03), acyl glycerol phosphate acyltransferase 6 by 15 % (P = 0·02) and diacylglycerol acyltransferase 1 by 27 % (P = 0·02), whereas the expression of fatty acid binding protein 3 was not altered by CLA treatment (P = 0·09). Mammary expression of casein-β and α-lactalbumin was reduced by CLA by 68 % (P = 0·0004) and 62 % (P = 0·005), respectively. Additionally, CLA had no effect on the expression of lipogenic genes evaluated in adipose tissue. In summary, CLA reduced milk fat content without negatively affecting litter performance and it affected mammary expression of genes involved in all lipogenic pathways studied.

Milk fatty acids as covariates in multiple regression analysis is a robust approach to model the decrease in milk fat concentration and yield in small ruminants

“…The significant covariates do not necessarily indicate a cause–effect relationship with the response variable; instead, they may have a relationship with other variables (latent variables) that indeed affect milk fat metabolism. For instance, CLA has been shown to downregulate the gene expression of regulatory enzymes in the de novo FA synthesis pathway (Bauman et al, 2008; Sandri et al, 2020; Ticiani et al, 2016). Therefore, the products of that metabolic pathway (i.e., SCFA and MCFA) may be significant predictors in models that estimate milk fat without direct affecting the response variable.…”

“…Other FA were included in three of the four regressions tested: c9, c12, c15‐18:3; c9‐18:1; 16:0; 6:0 and 4:0. The SCFA and MCFA are products of the de novo FA synthesis and this pathway may be inhibited by trans ‐10 FA (Bauman et al, 2008; Sandri et al, 2020; Ticiani et al, 2016), 16:0 (Carraro et al, 2019; Tian et al, 2017) and PUFA (Sampath & Ntambi, 2004; Toral et al, 2015). In addition, c9‐18:1 has been negatively related to the SCD gene in cows (Keating et al, 2006).…”

“…This FA inhibits lipogenic enzymes in the mammary gland in cows (Ticiani et al, 2016), sheep and goats (Della Badia et al, 2021), and in in vitro mammary epithelial cells (Kadegowda et al, 2009). The CLA is the main trans FA associated with the MFD syndrome (Bauman et al, 2008; Sandri et al, 2020; Ticiani et al, 2016), but the trans ‐10 18:1 (T10) has also been related to MFD in ruminants (Antonacci et al, 2018; McCarthy et al, 2018). However, more than one FA may be responsible for explaining the changes in milk fat synthesis (Alves & Bessa, 2014).…”

A Soap‐Free Strategy for One‐Pot Synthesizing Conjugated Linoleic Acid: Alkali Isomerization of Linoleic Acid through Preferential Esterification Pathway

“…The most predominant biologically active isomers in natural CLA are "c9, t11" CLA, and "t10, c12" CLA (Giordano et al, 2011). Previous studies have shown that natural CLA has the potential to reduce body fat (Sandri et al, 2020) and cholesterol (O'Reilly et al, 2020;Yeonhwa Park et al, 2010), and enhances immunity (Park et al, 2008). In addition to being the essential fatty acid for human, CLA is also the material for synthesizing some structured lipids (Zou et al, 2020).…”

Stearic acid does not overcome conjugated linoleic acid trans-10, cis-12-induced milk fat depression in lactating ewes

“…Inhibition of milk fat synthesis by the administration of trans-10, cis-12 CLA is mediated, at least in part, by down-regulating the gene expression of lipogenic enzymes and transcription factors in the mammary gland. Such effects have been demonstrated in several species of domestic animals, such as cows (8) , sheep (9) , goats (10) and sows (11) .…”