Finishing pig's responses to a diet incorporating unfermented or fermented palm kernel cake on growth performance, nutrient digestibility, digestive enzyme activity, short-chain fatty acid, and colonic microbiota composition

This study evaluated the effect of feeding finishing pigs a diet incorporating unfermented or fermented palm kernel cake (PKC) on growth performance, nutrient digestibility, digestive enzyme activity, short-chain fatty acid, and colonic microbiota composition. A total of 24 finishing pigs (5-month-old fattening castrated Duroc × Landrace × Large White pigs) were divided into three groups, namely, the control group (CON), unfermented palm kernel cake group (PKC group), and fermented palm kernel cake group (FPKC group), with eight replicates in each group and one finishing pig in each replicate. The CON group fed the finishing pigs a basal diet, while the PKC and the FPKC groups substituted 30% of the basal diet with either unfermented PKC or fermented PKC. The results showed that an unfermented or fermented PKC diet did not impact the pig's final body weight, average daily gain (ADG), average daily feed intake (ADFI), and tight junction proteins. Unfermented PKC had lower nutrient digestibility, feed conversion ratio, digestive enzyme activity, and intestinal morphology, and increased the activity of microbiota in the colon that breaks down fiber, resulting in an increase of butyric acid and valeric acid compared with the CON group (<italic>P &lt; 0.05</italic>). However, fermented PKC did not significantly differ from the CON group in most of the parameters (growth performance, digestive enzyme activity, short-chain fatty acids, intestinal morphology, tight junction, and most biochemical variables) that were tested in this study and showed a better improvement than unfermented PKC. Based on our findings (final body weight, colonic bacteria composition, and diversity) and the feed cost, fermented or unfermented PKC could be suggested to farmers as a better alternative to the lack of the main feedstock material used in pig farming, but FPKC is more suitable for utilization in finishing pigs.