The aim of the study was to analyse the expression of several microRNAs (miRNA) in the liver of pigs fed different diets. Twenty-four fatteners (12 gilts and 12 barrows) originating from (Polish Landrace × White Large Polish) sows mated with (Duroc × Pietrain) boars were divided into 4 dietary groups, with 6 pigs in each group (3 gilts and 3 barrows). The fattening experiment lasted from about 60 kg to 118 kg of body weight. The animals were fed diets that differ with the presence of maize dried distilled grains with solubles (DDGS; groups II, III, IV – 20%) and the type of used fat (rapeseed oil – groups I and II, beef tallow – group III, coconut oil – group IV). A qPCR analysis to assess miR-148a-3p, miR-122a, miR-26a, miR-103, let-7a, miR-92a, miR-335 and miR-16a expressions was performed. In the GeNorm software analysis it was shown that the most stably expressed miRNAs were miR-26a, miR-16a and miR-148a-3p (M values: 0.51–0.52). Only miR-122a expression was different (P < 0.03). The miR-122a level was statistically lower in the liver of pigs from group IV (DGS+coconut oil). The results suggest that adding coconut oil to feedstuff based on maize DDGS changes the expression of miR-122a, which is an important regulator of many genes engaged in lipid metabolism.