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

Abstract

In dairy cattle, diet supplementation with oils affects the lipid metabolism in body tissues via changes in the partitioning and deposition of fatty acids (FAs) and lipogenic gene expression; however, limited data are available in goats. Eight Alpine goats were fed a grassland hay diet supplemented with 90 g/day of sunflower-seed oil or 90 g/day of sunflower-seed oil and fish oil (2 : 1) plus additional starch. The goats were slaughtered on day 21 of the treatments and samples of the mammary secretory tissue, liver, omental and perirenal adipose tissues (ATs) were collected to characterise their FA composition and the mRNA abundance of lipogenic genes and transcription factors involved in their regulation, and to examine the impact of the diet composition on the same parameters. The results are in agreement with the specific physiological adaptation in the lipid metabolism of body tissues that is likely to occur during late lactation because of the coexistence of an active lipogenesis in the mammary secretory tissue and a significant anabolic activity in the ATs. These latter tissues were characterised by high concentrations of saturated FA and very low polyunsaturated FA (PUFA) levels. The content of PUFA was relatively higher in the mammary secretory tissue, in particular in the case of polyunsaturated C18. The highest PUFA contents were found in the liver, in accordance with the greater mRNA abundances of the genes that encode the necessary enzymes for very long-chain n-3 and n-6 PUFA synthesis. However, substantial differences between n-3 and n-6 pathways would most likely exist in the goat liver. Overall, differences in diet composition induced limited changes in the mRNA abundance of genes involved in lipid metabolism, and these were not associated with the few variations observed in tissue FA composition.

LCFA Uptake and FAT/CD36: molecular cloning, tissue expression and mRNA expression responses to dietary oil sources in grass carp (Ctenopharyngodon idellus)

“…Furthermore, Yang et al (2007) showed that FAs with a chain length longer than eight carbons could effectively inhibit FAT/CD36 expression in adipocytes, but unsaturated LCFAS had no effect. Dietary oil sources, such as lard oil, FO or sunflower-seed oil, differently influenced FAT/CD36 expression in the liver and muscle of rats (Feillet-Coudray et al 2013) and in the mammary secretory tissue and mental adipose tissue of goats (Toral et al 2013), whereas FAT/CD36 expression in the hepatopancreas was not affected by diets containing lard oil diet or FO in grass carp (Tian et al 2015). These previous studies give scarcely identical information on different longchain unsaturated FAs affecting FAT/CD36 expression.…”

Fish oil-induced milk fat depression and associated downregulation of mammary lipogenic genes in dairy ewes

“…For example, Hussein et al (2013) reported that trans-10 cis-12 CLA-induced MFD in lactating ewes involves the SREBF family and a coordinated downregulation of genes related to mammary lipid synthesis (e.g., ACACA, FASN, SCD1, AGPAT6, SREBF1 or INSIG1). In contrast, several studies in dairy sheep (Dervishi et al, 2012;Bichi et al, 2013a;Castro-Carrera et al, 2015) or dairy goats (Bernard et al, 2008;Tsiplakou et al, 2009;Toral et al, 2013) observed a weak relationship between changes in milk FA production and mammary mRNA abundance of key candidate genes and transcription factors involved in lipid metabolism. Yet, Bichi et al (2013a), who studied that relationship after 54 days on marine lipids, suggested that transcriptional regulation in dairy ewes might have been established earlier during the feeding period.…”

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

“…Concerning the FA profile of the mammary tissue, there is very little literature reporting this data in ruminants (Christie, 1981;Toral et al, 2013) and no information is available in lactating ewes. In the present study, the virtual absence of shorter-chain FA (4 to 9 carbons, which are present in the milk) would suggest not only that residual milk was well removed but also a minor contribution of unsecreted cytosolic lipid droplets to extracted lipids.…”