Effect of replacement of corn in feed with polished rice or combined polished rice and rice bran feeding on pork quality

Abstract

We examined the effect of the use of polished rice or the combination of polished rice and rice bran in feed on pork quality. Thirty-two Duroc gilts were assigned to 4 treatment groups. The average initial bodyweight of the pigs was 70kg. The treatments were as follows ; 70% corn diet as the control ; a polished rice (PR) treatment replacing corn ; polished rice+10% rice bran (60% PR+10% RB) treatment ; and polished rice+20% rice bran (50%PR+20% RB). All pigs were fed these diets until their live weight reached at 115kg. The L* value of the inner layer of backfat in the PR group was higher than that in the control. There were no differences in the L* value between the control and PR+10% and PR+20% groups. The percentage of oleic acid in the inner layer of backfat of the PR group was higher than that for the control. However, as the ratio of rice bran in diet increased, the percentage of oleic acid decreased to the same level as that in the control. Linoleic acid and α-linoleic acid levels in the PR group were lower than those in the control and increased to a level equivalent to or greater than that in the control as the ratio of rice bran in diet increased. From these results, the 70% polished rice diet increased L* value and oleic acid in the inner layer of backfat, and decreased polyunsaturated fatty acid levels. Higher rice bran with lower polished rice content in the diet reduced the difference in fatty acid composition between the control and PR groups.