Adipose tissue lipogenic gene networks due to lipid feeding and milk fat depression in lactating cows

Abstract

Dietary lipid supplements have been extensively evaluated for their effects on mammary tissue mRNA abundance, including the classical lipogenic genes ACACA, SCD, FASN, and the transcription regulators SREBF1, THRSP, and PPARG. Novel gene isoforms with key regulatory roles in triacylglycerol synthesis have been recently identified including LPIN1 and AGPAT6. Transcriptional networks (i.e., genes whose mRNA expression is regulated by a transcription factor or nuclear receptor) coordinate adipogenesis and lipid filling in nonruminant adipose tissue. To investigate whether long-term milk fat depression affects adipogenic networks in subcutaneous adipose tissue, we characterized mRNA expression via quantitative PCR of 20 genes in cows fed saturated and polyunsaturated lipid for 3 wk. Adipose tissue from cows fed a control diet, control with fish (10 g/kg of dry matter) and soybean oil (25 g/kg of dry matter) (FSO), or control with saturated lipid (35 g/kg, EB100; Energy Booster 100, Milk Specialties, Dundee, IL) was biopsied after 21 d of feeding. Milk production did not differ across treatments (averaged 32 kg +/- 2.8 kg/d during the 21 d) but dry matter intake (DMI) decreased in cows fed FSO versus controls (averaged 18 vs. 22 kg/d during the 21 d). Despite the decrease in DMI, FSO resulted in similar energy intake as EB100 during the last 2 wk of the study. Cows fed FSO had a gradual decline in milk fat and energy yield leading to an overall 25% decrease in milk fat yield during the study (averaged 0.90 vs. 1.2 kg/d) compared with control or EB100. Thus, during the 21-d study, FSO led to a gradual increase in intake energy available for adipose tissue deposition. Relative mRNA expression of LPL and SCD as well as ADFP (coding for a protein involved in lipid droplet formation) and LPIN1 (coding for a protein involved in diacylglycerol synthesis/transcriptional regulation) was upregulated with FSO relative to other diets. Expression of the transcription regulator THRSP tended to be greater in cows fed FSO. Overall, results suggest that long-term milk fat depression caused by feeding FSO provided additional energy as well as long-chain fatty acids that, coupled with upregulation of a subset of adipogenic genes in subcutaneous adipose tissue, might have resulted in greater tissue lipid deposition.

Effect of different dietary oil sources on the growth performance, blood characteristics, fatty acid profiles, and expression of lipogenic genes in the liver of broiler chickens

“…Marine n-3 PUFA have been found to be involved in the suppression of lipogenic genes in liver (Kaur and Sinclair 2010). In our study, feeding the diet enriched with n-3 PUFA significantly upregulated the relative mRNA expression of LPIN1, which was consistent with the report of Thering et al (2009). The significant changes for LPIN1 implied that its expression levels were under the post-transcription regulation.…”

Effects of fish oil and additional starch on tissue fatty acid profile and lipogenic gene mRNA abundance in lactating goats fed a diet containing sunflower-seed oil

“…Several studies have highlighted the stability of goat milk fat secretion and composition under a variety of feeding strategies (Chilliard et al, 2007), including diet supplementation with sunflower-seed oil and fish oil (Bernard et al, 2010), which is a combination of lipid supplements that causes milk fat depression in dairy cows and sheep (Thering et al, 2009;Invernizzi et al, 2010;Toral et al, 2010). Although comparisons between studies can seldom be made because of the few data available in goats and the variation in basal diet composition and/or lipid supplementation, inter-species differences in lipid metabolism have been highlighted previously (Chilliard et al, 2007).…”

“…In this regard, reductions in milk fat synthesis in cows fed plant oils rich in n-6 PUFA and fish oil have been related to variations in lipogenic gene expression not only in the mammary gland but also in other body tissues (Harvatine and Bauman, 2006;Thering et al, 2009;Invernizzi et al, 2010). Although these changes were attributed in cows to modifications in the partitioning of nutrients towards non-mammary tissues (Thering et al, 2009), studies in dairy goats characterising lipid metabolism in body tissues or nutritional regulation are still scant to assume that the same may happen in this species (Bernard et al, 2005a and. Further, there is no available information on simultaneous measurements of FA composition, expression of genes encoding key lipogenic enzymes and related transcription factors in goat body tissues.…”

Dietary sunflower oil modulates milk fatty acid composition without major changes in adipose and mammary tissue fatty acid profile or related gene mRNA abundance in sheep

“…Studies on diet-induced MFD in cows report an increase in the mRNA abundance of lipogenic genes in AT related to the preferential partitioning of nutrients towards non-mammary tissues (Harvatine et al, 2009;Thering et al, 2009;Schmitt et al, 2011). On the contrary, lipid supplementation inducing no changes or increases in milk fat yield in goats is not accompanied by alterations of the mRNA abundance or activity of lipogenic enzymes in AT (Bernard et al, 2005a and2009a).…”