Dietary Saury Oil Reduces Hyperglycemia and Hyperlipidemia in Diabetic KKAy Mice and in Diet‐Induced Obese C57BL/6J Mice by Altering Gene Expression

Abstract

We investigated the effect of saury oil on the alleviation of metabolic syndrome in mice. Saury oil contains 18% (w/w/) n-3 polyunsaturated fatty acids (n-3 PUFA) and 35% (w/w) monounsaturated fatty acids (MUFA). Diabetic KKAy mice were fed a 10% soybean oil diet (control) or a 10% saury oil diet for 4 weeks, and diet-induced obese C57BL/6J mice were fed a high-fat diet containing 32% lard (control) or 22% lard plus 10% saury oil for 6 weeks. After the intervention periods, the levels of glucose, insulin and lipids in plasma had decreased significantly for the saury oil diet group, and insulin sensitivity had improved. These favorable changes may be attributed to the increased adiponectin and decreased TNFα and resistin levels in plasma. The saury oil diet also resulted in downregulated expression of the lipogenic genes (SREBP-1, SCD-1, FAS, and ACC) as well as upregulation of the fatty acid oxidative gene, CPT-1, and the energy expenditure-related genes (PGC1α and PGC1β) in white adipose tissue for the diet-induced obese C57BL/6J mice. An increase in n-3 PUFA levels and the concomitant decrease in the n-6/n-3 PUFA level ratio in serum, white adipose tissue, and liver with a saury oil diet are likely to be involved in the beneficial changes to the metabolic indicators. MUFA may also play a positive role in remodeling lipid composition. Based on these mice models, our results suggest a potential use for saury oil for improving metabolic abnormalities.

Influence of genotype on the modulation of gene and protein expression by n-3 LC-PUFA in rats

“…Although EPA and DHA effect on Srebf-1 expression was influenced by the genetic variation, no significant modifications in the level of both uncleaved and cleaved SREBP-1 were detected upon PUFA supplementation in either WK or SH rats. This discrepancy from previous studies could be dependent on the different experimental model, that is in vivo study versus cultured liver cells (Kohan et al 2011), to the different FA concentration in the diet and to the different length of the dietary treatment (Lu et al 2011), or to the use of purified EPA and DHA in spite of oils for dietary supplementation (Yang et al 2011). Although the inability of PUFA in modifying active SREBP-1 level in our experimental condition, as well as the low level of uncleaved SREBP-1 observed in SH rats, deserves further attention to our aim, the most relevant data were the evidence of a different modulation of Srebpf-1 expression by PUFA in the two strains.…”

A Comparative Analysis of Saturated (SFAs) and Unsaturated (UNFAs) Fatty Acids in Chickens Oil and its Impact on Type 2 Diabetes Mellitus in Experimental Rats

“…C -reactive protein (CRP) is a simple cost effective test, which can predict the cardiovascular risk. The addition of CRP-testing to standard lipid screening appears to provide an important method to determine Cardiovascular Disease (CVD) risk factor [19,20]. Dietary supplementation of HFO declined CRP level significantly and thus reduced the risk of cardiovascular diseases.…”

Should the pharmacological actions of dietary fatty acids in cardiometabolic disorders be classified based on biological or chemical function?

“…Evidence on the biological activity of long-30 chain MUFA from marine sources has been emerging from animal experiments. Saury oil insulin sensitivity, decreased blood glucose and lipid concentrations, increased circulating 1 adiponectin and decreased TNFα and resistin in diet-induced obese mice [169]. These 2 changes were associated with down-regulation of lipogenic genes (SREBP-1, SCD-1, FAS 3 and ACC) and a concomitant up-regulation of fatty acid oxidative genes, CPT-1, and the 4 energy expenditure-related genes (PGC1α and PGC1β) in white adipose tissue [169].…”

“…Saury oil insulin sensitivity, decreased blood glucose and lipid concentrations, increased circulating 1 adiponectin and decreased TNFα and resistin in diet-induced obese mice [169]. These 2 changes were associated with down-regulation of lipogenic genes (SREBP-1, SCD-1, FAS 3 and ACC) and a concomitant up-regulation of fatty acid oxidative genes, CPT-1, and the 4 energy expenditure-related genes (PGC1α and PGC1β) in white adipose tissue [169]. Similar 5 effects were observed with 5% saury oil-derived MUFA diet for 6 weeks in diet-induced 6 obese mice along with decreased expression of inflammatory genes (MAC1, MMP3, and 7 SAA3) [225].…”

“…The other major MUFA is palmitoleic acid, produced by the desaturation of 25 palmitic acid in the de novo lipogenic pathway [164], but it does not occur in high amounts in 26 common dietary sources. Long chain MUFA such as gondoic acid (C20:1n-9), erucic acid 27 (C22:1n-9) and cetoleic acid (C22:1n-11) may also be present in the diets rich in saury oil, 28 mustard seed oil, rapeseed oil, poultry and processed meat (Table 1) [169,170]. 29…”