Effect of Western Diet and Caloric Substitution with Apple Pomace on Fatty Acid Composition and Gene Expression in the Hypothalamus of Growing Female Sprague-Dawley Rats

Apple pomace, which is a waste byproduct of processing, is rich in several nutrients, particularly dietary fiber, indicating potential benefits for diseases that are attributed to poor diets, such as non-alcoholic fatty liver disease (NAFLD). NAFLD affects over 25% of United States population and is increasing in children. Increasing fruit consumption can influence NAFLD. The study objective was to replace calories in standard or Western diets with apple pomace to determine the effects on genes regulating hepatic lipid metabolism and on risk of NAFLD. Female Sprague-Dawley rats were randomly assigned (n = 8 rats/group) to isocaloric diets of AIN-93G and AIN-93G/10% w/w apple pomace (AIN/AP) or isocaloric diets of Western (45% fat, 33% sucrose) and Western/10% w/w apple pomace (Western/AP) diets for eight weeks. There were no significant effects on hepatic lipid metabolism in rats fed AIN/AP. Western/AP diet containing fiber-rich apple pomace attenuated fat vacuole infiltration, elevated monounsaturated fatty acid content, and triglyceride storage in the liver due to higher circulating bile and upregulated hepatic DGAT2 gene expression induced by feeding a Western diet. The study results showed the replacement of calories in Western diet with apple pomace attenuated NAFLD risk. Therefore, apple pomace has the potential to be developed into a sustainable functional food for human consumption.

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Effects of dietary n -6: n -3 PUFA ratio on the growth performance, serum lipid and adipokine profiles, tissue fatty acid composition and gene expression of lipid metabolism of finishing pigs

10.21203/rs.3.rs-127949/v1 ◽

2020 ◽

Author(s):

Jing Chen ◽

Jiantao Li ◽

Xianjun Liu ◽

Hongze Cui ◽

Liyan Wang ◽

...

Keyword(s):

Gene Expression ◽

Fatty Acid Composition ◽

Fatty Acid ◽

Lipid Metabolism ◽

Growth Performance ◽

Acid Composition ◽

Blood Lipid ◽

Finishing Pigs ◽

Pufa Ratio ◽

Tissue Fatty Acid Composition

Abstract Background The health benefits of n-3 polyunsaturated fatty acids (PUFA), such as cardioprotective, anti-inflammatory and hypo-triglyceridemic properties, have been well documented. However, current dietary modification can easily lead to excessive concentrations of n-6 PUFA and an imbalance in the n-6:n-3 PUFA ratio, resulting in the pathogenesis of obesity and related diseases. This study investigated the effects of various dietary n-6:n-3 PUFA ratios on the growth performance, blood lipid and cytokine profiles, tissue fatty acid composition, and gene expression involved in lipid metabolism in finishing pigs. Seventy-two crossbred [(Duroc × Landrace) × Yorkshire] finishing pigs (68.5 ± 1·8 kg) were fed one of four isoenergetic diets with n-6:n-3 PUFA ratios of 2:1, 3:1, 5:1 and 8:1. Results Pigs fed diets with n-6:n-3 PUFA ratios of 3:1 and 5:1 had a higher average daily gain (ADG) and average daily feed intake (ADFI) (P < 0.05) and a lower feed conversion ratio (FCR) (P < 0.05). The concentrations of triglyceride (TG) and total cholesterol (TC) of pigs fed diets with n-6:n-3 PUFA ratios of 1:1 to 5:1 decreased (P < 0·05), whereas the ratio of concentrations of high-density to low-density lipoprotein cholesterol (HDL-C:LDL-C) in pigs fed a diet with an n-6:n-3 PUFA ratio of 2:1 increased (P < 0·05) compared with those fed a diet with an n-6:n-3 PUFA ratio of 8:1. Pigs fed a diet with n-6:n-3 PUFA ratios of 2:1 and 3:1 had lower concentrations of leptin (LEP) and interleukin 6 (IL-6) (P < 0·05), and higher concentrations of adiponectin (APN) (P < 0·05) than those fed diets with n-6:n-3 PUFA ratios of 5:1 and 8:1. Diets with n-6:n-3 PUFA ratios of 2:1 and 3:1 markedly down-regulated the expression levels of peroxisome proliferator-activated receptor-γ (PPARγ) and lipoprotein lipase (LPL) in both the longissimus dorsi muscle (LM) and subcutaneous adipose tissue (SCAT), but up-regulated the expression level of adipocyte fatty acid binding protein (aP2) in the LM. The expression levels of aP2 and hormone- sensitive lipase were similar to those of PPARγ in the SCAT. Conclusions This study demonstrated that dietary n-6:n-3 PUFA ratios between 3:1 and 5:1 beneficially affected growth performance, optimize blood lipid and adipocytokine levels, enhanced absorption and deposition of n-3 PUFA and regulated lipid metabolism-related genes.

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