The addition of humic substances extracted from vermicompost enhances the growth performance and the antioxidant status of weaning pigs

The aim of the study was to assess the effect of humic substances (HS) extracted from vermicompost on the growth performance, fecal score, bone ash content and antioxidant status in muscles and blood serum of weaned pigs from 1-42 days postweaning. Two-hundred 22-day weaned pigs were assigned to four treatments: 1= Positive control diet with colistin (PC), 2= Negative control diet without antibiotic or HS (NC), 3 and 4= Diets with 2 500 and 5 000 ppm of HS, respectively. Growth performance, fecal consistency, dry matter and ashes of metatarsus and the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, iron reducing ability and thiobarbituric acid reactive substances in muscles and blood were registered. Results were subjected to ANOVA and regression analysis. Linear increasing responses (P < 0.05) were found in the body weight at 42 days postweaning, the ADG from 1-7, 8-21, 22-42 and 1-42 and the gain:feed ratio from 1-7, 22-42 and 1-42 days postweaning, whilst the fecal score decreased linearly (P < 0.01) from 1-7, 8-21 and 1-42 days postweaning due to the increasing dietary HS concentration. The antioxidant potential of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (P < 0.05) in loin muscle and blood serum at three and seven days, and in fillet muscle at seven days postweaning increased linearly due to the increasing dietary HS concentration. It is concluded that the addition of HS improved the growth performance from 1-42 days postweaning and the antioxidant status in muscles and blood serum of weaned pigs at three and seven days postweaning.