The composition of dietary fat alters the transcriptional profile of pathways associated with lipid metabolism in the liver and adipose tissue in the pig1

Abstract

The objective was to investigate the of effect chemical composition of dietary fat on transcription of genes involved in lipid metabolism in adipose tissue and the liver via transcriptional profiling in growing pigs. A total of 48 Genetiporc 6.0 × Genetiporc F25 (PIC, Inc., Hendersonville, TN) barrows (initial BW of 44.1 ± 1.2 kg) were randomly allotted to 1 of 6 dietary treatments. Each experimental diet included 95% of a corn-soybean meal basal diet and 5% cornstarch (control; CNTR), animal-vegetable blend (AV), coconut oil (COCO), corn oil (COIL), fish oil (FO), or tallow (TAL). Pigs were sacrificed on d 10 (final BW of 51.2 ± 1.7 kg) to collect tissues. Expression normalization across samples was performed by calculating a delta cycle threshold (ΔCt) value using . Delta delta cycle threshold (ΔΔCt) values were expressed relative to the CNTR treatment. In adipose tissue, adding dietary fat, regardless of the source, decreased the mRNA abundance of compared with the CNTR ( = 0.014). Pigs fed a COIL-based diet tended to have greater adipose tissue expression of ( = 0.071) than pigs fed the other dietary fat sources tested. Abundance of mRNA was greater in adipose tissue of barrows a fed COIL-based diet than barrows fed CNTR or FO-based diets ( = 0.047). In the liver, adding dietary fat, regardless of source, increased the mRNA abundance of , , , , , and ( ≤ 0.020) and tended to increase the abundance of ( = 0.071) and ( = 0.086) compared with the CNTR. Pigs fed a TAL-based diet had greater hepatic transcription of than pigs fed CNTR-, COCO-, or FO-based diets ( = 0.013). Hepatic transcription of tended to be greater in pigs fed COCO than in pigs fed other dietary fat sources ( = 0.074). Dietary omega-3 fatty acid content tended to negatively correlate with mRNA abundance of ( = 0.065) in adipose tissue and ( = 0.063) in the liver. Dietary fat SFA content was negatively correlated with in the liver ( ≤ 0.039). Dietary fat MUFA content tended to be positively correlated with , , and mRNA abundance in the liver ( ≤ 0.100). To conclude, the intake of omega-3 fatty acids suppressed the mRNA abundance of genes involved in lipolysis in both adipose tissue and the liver. Dietary SFA are greater inhibitors of lipogenesis in adipose tissue than omega-6 fatty acids. Intake of medium-chain fatty acids alters hepatic lipid metabolism differently than intake of long-chain fatty acids.

The effects of dietary essential fatty acid ratios and energy level on growth performance, lipid metabolism, and inflammation in grow-finish pigs

“…The ACACA gene encodes for acetyl-CoA carboxylase, which is the enzyme responsible for the irreversible conversion of acetyl-CoA to malonyl-CoA as the first step for fatty acid synthesis. The increase in liver ACACA relative mRNA abundance in lower-energy diets compared to high-energy diets is supported by previous work ( Duran-Montgé et al, 2009 ; Kellner et al, 2017 ). Duran-Montgé et al (2009) observed an increase in liver ACACA only in pigs fed 10% high oleic sunflower oil compared to a no-fat diet, but no differences when fed 10% tallow, sunflower oil, linseed oil, a fish oil blend, or a tallow, sunflower oil, and linseed oil blend.…”

“…In the current study, ACACA abundance increased in adipose tissue, which agrees with Duran-Montgé et al (2009) , who reported reduced adipose ACACA abundance with added dietary fat, regardless of source. In adipose tissue, Kellner et al (2017) did not report a significant change in ACACA abundance with 5% added fat. Differences in adipose ACACA abundance between Kellner et al (2017) and the data reported herein could be a result of the longer 84-d feeding duration of high-energy diets in the current study, compared to the 10-d experimental period used by Kellner et al (2017) .…”

“…In adipose tissue, Kellner et al (2017) did not report a significant change in ACACA abundance with 5% added fat. Differences in adipose ACACA abundance between Kellner et al (2017) and the data reported herein could be a result of the longer 84-d feeding duration of high-energy diets in the current study, compared to the 10-d experimental period used by Kellner et al (2017) .…”

“…This ratio can be even higher depending on the dietary lipid source utilized, resulting in LA being the primary substrate for the pathway. Substantial research exists evaluating how dietary fat source impacts growth, lipid metabolism, and inflammation in pigs across production phases ( Liu, 2015 , Kellner et al, 2017 ; Lauridsen, 2020 ; Wang et al, 2022 ). In swine production, lameness represents a significant cost during the grow-finish phases, as well as in gilt development, and ultimately in the breeding herd.…”

Corn dried distillers grains with solubles (cDDGS) in the diet of pigs change the expression of adipose genes that are potential therapeutic targets in metabolic and cardiovascular diseases

“…In fact, as a byproduct of alcohol production, cDDGS contains a substantial amount of yeast debris [ 13 ]. It also contains high amounts of polyunsaturated fatty acids, which are well-known inhibitors of lipogenesis through the downregulation of SCD and FASN [ 23 , 24 ]. In addition, cDDGS contain high amounts of fiber, which has strong anti-lipogenic activity [ 9 ].…”