Effects of fulvic acid on growth performance and meat quality in growing-finishing pigs

An experiment was conducted to evaluate the effects of dietary fulvic acid (FA) on growth performance and meat quality in growing-finishing pigs. Two hundred and sixteen (30.0±2.5 kg body weight) crossbred (Landrace×Yorkshire) castrated male pigs were randomly allotted to 6 dietary treatments with 6 replicates (pens) per treatment and 6 pigs per pen. The basal diet was supplemented with different levels of FA (0.0%, 0.1%, 0.2%, 0.4%, 0.6%, and 0.8%). Pigs were fed diets based on a 2-phase feeding program (phase 1 for 45 d, and phase 2 for 42 d). The results from the entire experimental period showed pigs fed diets supplemented with FA increased average daily gain (ADG) linearly and quadratically (P<0.05) during phase 1 and the whole feeding period, respectively, whereas gain to feed ratio (G:F) was increased quadratically (P<0.05). Dietary supplementation of FA did not affect ADG and average daily feed intake during phase 2, but G:F was increased quadratically (P<0.05). The slaughter weight and hot carcass weight of pigs fed diets supplemented with FA increased linearly and quadratically (P<0.05). The backfat thickness was reduced (P<0.05) quadratically in response to dietary FA supplementation. Feeding diets supplemented with FA reduced pH in muscle (24 h) linearly (P<0.05) and malonaldehyde (MDA) quadratically (P<0.05), while a⁎ value, b⁎ value, and marbling increased linearly and quadratically (P<0.05). The results of this study indicated that supplementation of diets with FA is an effective way to increase growth performance, reduce backfat thickness, and improve meat quality in growing-finishing pig. Broken-line regression analysis indicated that the optimum dietary FA supplementation to increase G:F and reduce backfat thickness and MDA under the current experimental conditions was 0.48-0.79%.