Abstract
The present study was conducted to elucidate the possibilities of red rice and black rice as the source of antioxidant component for pigs and the effects of feeding of red rice or black rice on anti-oxidative status of the gilts. Elution of antioxidant component from corn, two kinds of brown rice, red rice, and black rice were evaluated by in vitro digestion test. Corn and rice samples milled through 1mm screen were digested in test tube. HCl-pepsin reaction for 4 hours and following pancreatin reaction for 4 hours were performed in 39°C assuming in stomach and small intestine, respectively. After the centrifugation of the digests, the supernatants were subjected to total antioxidant status (TAS) kit to evaluate antioxidative activity. From 1 g of corn and two kinds of brown rice, antioxidant components were eluted by 17.5, 21.0, and 19.9 μmol (Trolox equivalent) respectively, while 27.4 μmol (1.6-fold of corn) was eluted from red rice. Significantly high level of antioxidant components elution was observed in black rice (125.2 μmol, 7.2-fold of corn). Furthermore, even when the step of pancreatin reaction was skipped, 91% of antioxidant component was detected in case of black rice. Next, Eight LWD gilts with the weight of about 110 kg were examined under high ambient temperature. After keeping at 32°C for 20 days, experimental period started also at 32°C. The experiment was done by a Latin square of 4 feeds x 4 terms (seven days for 1 term). For the first four days of examination term, 2.2 kg of control diet mainly consisted by corn was given to the gilts once a day. For the last three days of the examination term, 2.2 kg of the control diet or the experimental diets containing brown rice, red rice, or black rice by 50% respectively, was given to the gilts once a day. On the first day of experimental diet, blood samples were collected at 0, 1, 2, and 4 hours after feeding, and urine samples were collected on the next day. Blood plasma antioxidant status was evaluated with TAS kit. TAS value of the gilt fed black rice diet was significantly increased 1 hour after ingestion (P<0.05), and fell gradually. A clear change was not seen in gilts fed control diet, brown rice diet, or red rice diet. Creatinine-adjusted urinary 8-OHdG concentration was measured to assess the oxidative stress, but no difference was observed.
