Fermented garlic powder supplementation: effects on growth performance, blood characteristics and meat quality in finishing pigs fed low-nutrient-density diets

Recently, phytogenic feed additives have gained much attention as an alternative to antibiotic growth promoters. Accordingly, various herbs or their extracts are now being utilized as feed additives due to their widespread antioxidative and antimicrobial actions, beneficial effects on palatability and gut functions. Garlic (Allium sativum), which has been used as spice and folk medicine since antiquity, has been considered to be beneficial to animal health as the allicin, the bioactive substance of garlic, has antibacterial, antiparasite and antifungal activities. Therefore, the objective of this study was to evaluate if fermented garlic powder with low-nutrient-density diets can improve growth performance, blood characteristics and meat quality in finishing pigs to levels similar with those of comparative high-nutrient-density diet. A total of 96 [(Landrace×Yorkshire)×Duroc] pigs with an initial body weight (BW) of 55.80±1.81 kg were used in a 12-week experiment. Pigs were randomly allotted to 1 of 4 treatments according to their sex and BW (6 replicates, 4 pigs per pen, 2 gilts and 2 barrows). Dietary treatments included: 1, HC (negative control; high-nutrient-density diet); 2, LC (positive control; low-nutrient-density diet); 3, LG2 (LC+2 g/kg fermented garlic powder) and 4, LG4 (LC+4 g/kg fermented garlic powder). The pigs were subjected to a 2- period feeding program consisting of early finisher (0 to 6 weeks) and late finisher (6 to 12 weeks) periods.

The average daily gain (ADG) in LG2 treatment was higher (P<0.05) than other groups during 0 to 6 weeks. The average daily feed intake (ADFI) was greater (P<0.05) in the LG2 group than that in HC and LG4 diets. During 6 to 12 weeks, pigs fed diets including fermented garlic powder increased ADG greatly (P<0.05) compared to HC and LC groups. Furthermore LG2 treatment led to a higher ADFI (P<0.05) than LC diet. Gain/feed (G/F) ratio was improved (P<0.05) when pigs fed LG4 diet compared to those fed HC or LC. Pigs fed LG2 diet increased ADG (P<0.05) significantly when compared with those fed HC or LC diets over the trial. Additionally, LG2 treatment had a higher ADFI (P<0.05) than LC and LC4 treatments. In sensory evaluation, pigs fed garlic supplementation showed a higher marbling score (P<0.05) than that in HC and LC treatments. Firmness score was greater (P<0.05) in LG2 treatment than that in other treatments. However, no other difference was observed in pH, meat color and drip loss during the experiment period.

These results indicated that fermented garlic powder supplementation at the level of 2 g/kg could improve growth performance and concomitantly meat marbling and firmness score.