EPA reduces hepatic triglycerides (TG) in UCP1 KO males independent of body weight. (A) Final body weights of male and female wild type (WT) and UCP1 knockout (KO) mice. UCP1 KO significantly increased body weight in males but had no impact in female mice. There was no significant impact of EPA on body weight in either WT or KO male or female mice groups. Data are expressed as mean ± SEM, n = 13–15, means without a common letter (a,b) differ in each group of males and females; groups with any common letter are not different from each other (a or b vs. ab). NS indicates no significant post-hoc comparisons (B) Hepatic TG content in male and female WT-HF, WT-EPA, KO-HF and KO-EPA groups. UCP1 KO significantly increased hepatic TGs in males, which was significantly reduced with EPA. Data are expressed as mean ± SEM, n = 4–6, means without a common letter (a, b) differ in each male or female group; means with any common letter are not different from each other (a or b vs. ab). NS indicates no significant post-hoc comparisons. (C) Representative hematoxylin and eosin-stained sections of the liver from WT-HF, WT-EPA, KO-HF and KO-EPA groups are shown for both male and female mice.