Effects of Fat Supplementation in Dairy Goats on Lipid Metabolism and Health Status.

Fat supplementation has long been used in dairy ruminant nutrition to increase the fat content of milk and supply energy during particularly challenging production phases. Throughout the years, advances have been made in the knowledge of metabolic pathways and technological treatments of dietary fatty acids (FAs), resulting in safer and more widely available lipid supplements. There is an awareness of the positive nutraceutical effects of the addition of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to fat supplementation, which provides consumers with healthier animal products through manipulation of their characteristics. If it is true that benefits to human health can be derived from the consumption of animal products rich in bioactive fatty acids (FAs), then it is reasonable to think that the same effect can occur in the animals to which the supplements are administered. Therefore, recent advances in fat supplementation of dairy goats with reference to the effect on health status have been summarized. In vivo trials and in vitro analysis on cultured cells, as well as histological and transcriptomic analyses of hepatic and adipose tissue, have been reviewed in order to assess documented relationships between specific FAs, lipid metabolism, and immunity.

Saturated or unsaturated fat supplemented maternal diets influence omental adipose tissue proteome of suckling goat-kids.

The aim of the present study was to investigate how maternal diet can influence the adipose tissue of goat kids. Omental adipose tissue proteomes of goat-kids from mothers fed with diet enriched with stearic acid (ST-kids), fish oil (FO-kids) and standard diets (CTRL) were determined by quantitative iTRAQ 2D-LC-MS/MS analysis. Twenty proteins were found to be differentially expressed in suckling kids' omental adipose tissue. Stearic acid induces changes in a higher number of proteins when compared to fish oil. Eleven proteins, namely AARS, ECl1, PMSC2, CP, HSPA8, GPD1, RPL7, OGDH, RPL24, FGA and RPL5 were decreased in ST-kids only. Four proteins, namely DLST, EEF1G, BCAP31 and RALA were decreased in FO-kids only, and one, NUCKS1, was increased. Four proteins, namely PMSC1, PPIB, TUB5×2 and EIF5A1, were be less abundant in both ST- and FO- kids. Most of the protein whose abundance was decreased in ST kids (10 out of 15) are involved in protein metabolism and catabolism pathways. Qualitative gene expression analysis confirmed that all the proteins identified by mass spectrometry, with the exception of FGA, were produced by adipose tissue. Quantitative gene expression analysis demonstrated that two proteins, namely CP, a minor acute phase protein, and ECl1, involved in fatty acid beta oxidation, were downregulated at mRNA level as well. ECl1 gene expression was downregulated in ST-kids AT as compared to Ctrl-kids and CP was downregulated in both ST- and FO-kids. The present results demonstrate that it is possible to influence adipose goat-kid proteome by modifying the maternal diet.

Sustained upregulation of stearoyl-CoA desaturase in bovine mammary tissue with contrasting changes in milk fat synthesis and lipogenic gene networks caused by lipid supplements.

Long-term mammary expression patterns of lipogenic gene networks due to dietary lipid remain largely unknown. Mammary tissue was biopsied for transcript profiling of 29 genes at 0, 7, and 21 days of feeding cows saturated lipid (EB100) or a blend of fish/soybean oil (FSO) to depress milk fat. Milk fat yield decreased gradually with FSO and coincided with lower molar yield of fatty acids synthesized de novo, stearic acid, and oleic acid. The PPARγ targets LPIN1 and SREBF1 along with ACSS2, ACACA, FASN, and LPL increased by day 7 of feeding EB100, but differences between diets disappeared by day 21. Expression of SCAP increased markedly over time with FSO and differed from EB100 by approximately sevenfold on day 21. Expression of THRSP decreased by day 7 with both diets and returned to basal levels by day 21. SCD expression increased linearly through 7 days and remained elevated with both diets, a likely mechanism to ensure the proper level of endogenous oleic acid via desaturation of dietary stearate (EB100) or via more SCD protein to account for the reduction in stearate supply from the rumen (FSO). Despite this response, endogenous oleate was insufficient to restore normal milk fat synthesis. Only 2 of 29 genes differed in expression between diets on day 21, suggesting that transcriptional control mechanisms regulating fat synthesis were established as early as 7 days post-feeding. Gene expression reflected vastly different physiological responses by mammary tissue to adjust its metabolism to the influx of saturated fatty acids, trans10-18:1, and/or to the lack of stearic acid.