Effects of diet enriched with restructured meats, containing Himanthalia elongata, on hypercholesterolaemic induction, CYP7A1 expression and antioxidant enzyme activity and expression in growing rats

Abstract

Meat and pork consumptions are very high in Spain. Seaweeds are rich in fibre, minerals, and bioactive substances. Due to the growing demand for healthier meats, this work studied the effect of diets containing restructured pork (RP) enriched with Himanthalia elongata (Sea Spaghetti) on: (1) cholesterolaemia; (2) liver cytochrome P450 7A1 (CYP7A1) expression; (3) liver antioxidant enzyme activities and gene expression; (4) the liver antioxidant substrate concentrations. Four groups of 10 Wistar rats each were fed a mix of 85% AIN-93M rodent diet and 15% freeze-dried RM for 35days. The control group (C) consumed control RP; the Sea Spaghetti (SS) group, RP with 5% Sea Spaghetti. Animals on added cholesterol diets (CholC and CholSS) consumed their basal C and SS diets enriched with cholesterol and cholic acid as hypercholesterolaemic agent. Food intake was significantly affected by the alga×cholesterol interaction and by dietary cholesterol (both p<0.001). Plasma cholesterol was significantly affected by the cholesterol×alga interaction (p<0.05). CholC rats showed significantly higher plasma cholesterol (p<0.001) than did their C counterparts, whilst serum cholesterol of CholSS was significantly lower (p<0.05) than that of CholC. The glutathione peroxide (GSSG) concentrations and all mRNA expressions were significantly affected by the cholesterol×alga interaction (at least p<0.05). SS vs C group showed significant (at least p<0.05) increases in superoxide dismutase (Mn-SOD and Cu,Zn-SOD), glutathione peroxidase (GPx) and decrease of glutathione reductase (GR) expressions, and increased GR activity, GSSG and the redox index. CholSS vs CholC showed significant (at least p<0.05) increases of CYP7A1, GR and Cu,Zn-SOD expression but decreases in catalase, Mn-SOD and GPx expression, and increase of GR activity. In conclusion, Sea Spaghetti could be widely used in RP design. Its addition to non-cholesterol enriched RP diet reduced oxidation mechanisms. SS-RP partially blocked the effect of the hypercholesterolaemic agent, giving rise to a new balance of the antioxidant enzyme expression.