Impact of dietary fat levels and fatty acid composition on milk fat synthesis in sows at peak lactation

Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis,and milk fatty acid(FA)output is sparse in sows.This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows.Forty second-parity sows(Danish Landrace×Yorkshire)were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning(d 28 of lactation):low-fat control diet(3%added animal fat);or 1 of 4 high-fat diets with 8%added fat:coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4%octanoic acid plus 4%FO(OFO).Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.Results Daily intake of FA was lowest in low-fat sows within fat levels(P<0.01)and in OFO and FO sows within highfat diets(P<0.01).Daily milk outputs of fat,FA,energy,and FA-derived carbon reflected to a large extent the intake of those.On average,estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo+mobilized FA/d according to method 3.The low-fat diet increased mammary FAS expression(P<0.05)and de novo fat synthesis(method 1;P=0.13)within fat levels.The OFO diet increased de novo fat synthesis(method 1;P<0.05)and numerically upregulated mammary FAS expression compared to the other high-fat diets.Across diets,a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.Conclusions Sows fed diets with low-fat or octanoic acid,through upregulating FAS expression,increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets,indicating that dietary FA intake,dietary fat level,and body fat mobilization in concert determine de novo fat synthesis,amount and profiles of FA in milk.

Dietary fatty acids and bioactive fatty acid metabolites in alcoholic liver disease

Alcoholic liver disease(ALD)comprises a spectrum of liver pathology,including steatosis,steatohepatitis,and cirrhosis.Previous work from our group and others suggests that dietary fat,both the amount and composition,plays a pivotal role in ALD development and progression;however,the impact of specific dietary fatty acids on ALD pathogenesis is not fully elucidated.Preclinical rodent models of ALD revealed the deleterious effects of omega-6 polyunsaturated fatty acids(n-6 PUFAs),specifically linoleic acid(LA),and this may be partially attributed to the increased levels of pro-inflammatory oxidized LA metabolites.There is limited understanding regarding the role of omega-3 polyunsaturated fatty acids(n-3 PUFAs,such as alpha-linolenic acid,eicosapentaenoic acid,and docosahexaenoic acid),and bioactive n-3 PUFAderived lipid molecules in ALD.Given that majority of n-6 and n-3 PUFAs-derived metabolites are potent endogenous signaling molecules,knowledge regarding the changes in these lipid mediators may shed new light on the mechanisms contributing to ALD pathogenesis and reveal novel therapeutic targets and biomarkers of this disease.The current review summarizes relevant scientific literature regarding the role of dietary fat,distinct fatty acids,and bioactive fatty acid metabolites in ALD,and highlights recent advances in the field.

Advances in fatty acids nutrition in dairy cows: from gut to cells and effects on performance

High producing dairy cows generally receive in the diet up to 5–6% of fat. This is a relatively low amount of fat in the diet compared to diets in monogastrics;however, dietary fat is important for dairy cows as demonstrated by the benefits of supplementing cows with various fatty acids(FA). Several FA are highly bioactive, especially by affecting the transcriptome;thus, they have nutrigenomic effects. In the present review, we provide an up-to-date understanding of the utilization of FA by dairy cows including the main processes affecting FA in the rumen,molecular aspects of the absorption of FA by the gut, synthesis, secretion, and utilization of chylomicrons;uptake and metabolism of FA by peripheral tissues, with a main emphasis on the liver, and main transcription factors regulated by FA. Most of the advances in FA utilization by rumen microorganisms and intestinal absorption of FA in dairy cows were made before the end of the last century with little information generated afterwards. However,large advances on the molecular aspects of intestinal absorption and cellular uptake of FA were made on monogastric species in the last 20 years. We provide a model of FA utilization in dairy cows by using information generated in monogastrics and enriching it with data produced in dairy cows. We also reviewed the latest studies on the effects of dietary FA on milk yield, milk fatty acid composition, reproduction, and health in dairy cows. The reviewed data revealed a complex picture with the FA being active in each step of the way, starting from influencing rumen microbiota, regulating intestinal absorption, and affecting cellular uptake and utilization by peripheral tissues, making prediction on in vivo nutrigenomic effects of FA challenging.

Benefits and risks associated with consumption of Great Lakes fish containing omega-3 fatty acids and polychlorinated biphenyls(PCBs)

Introduction Assessment of environmental health effects arising from exposure to multiple substances is often very challenging.This is particularly true when humans are exposed to a mixture that contains both beneficial and harmful substances.A good example relates to the risk and benefits of fish consumption.