Effects of Substitution of Corn with Brown Rice on Growth Performance, Nutrient Digestibility, and Blood Profiles of Weaned Pigs

A study was conducted to evaluate effects of substitution of corn with brown rice on growth performance, nutrient digestibility, and blood profiles of weaned pigs. A total of 144 weaned pigs (7.06 ± 0.57 kg BW; 28 d old) were randomly allotted to 4 dietary treatments (6 pigs/pen; 6 replicates/treatment) in a randomized complete block design (blocks=BW). Dietary treatments were a nursery diet based on corn-soybean meal basal diet (CON) and three additional diets formulated by replacing corn with 50% (BR50), 75% (BR 75), and 100% (BR100) of brown rice. The diets did not include animal plasma, fish meal, zinc oxide, or antibiotics to avoid their antibacterial or physiological effects. Pigs were fed respective dietary treatments for 6 weeks. For the last week of experiment period, pigs were fed respective dietary treatments containing 0.3% chromic oxide as an indigestible marker. Fecal samples were collected from randomly selected 1 pig in each pen daily for the last 3 d after the 4-d adjustment period. Blood was collected from randomly selected 1 pig in each pen on d 1, 3, 7, and 14 after weaning. Measurements were growth performance, frequency of diarrhea, nutrient digestibility by an index method, and blood profiles by an automated hematology analyzer calibrated for porcine blood. Data were analyzed using the PROC GLM procedure of SAS. The statistical model for every measurement except frequency of diarrhea included dietary effect as a fixed effect and BW as a covariate. The chi-squared test was used for the frequency of diarrhea. There were no differences on growth performance (ADG: 448, 479, 456, and 479 g/d; ADFI: 697,710,718, and 704 g/d; for CON, BR50, BR75, and BR100, respectively) during overall experimental period and frequency of diarrhea, number of white blood cells, and packed cell volume for the first 2 wk after weaning among dietary treatments. However, BR50, BR75, and BR100 increased (P < 0.05) apparent total tract digestibility (ATTD) of dry matter (90.26, 90.51, and 89.88 vs. 86.33%) and energy (90.40, 90.02, and 89.52 vs. 84.60%) compared with CON, but did not affect ATTD of crude protein. In conclusion, substitution of corn with brown rice in nursery diets had no negative effects on growth performance, nutrient digestibility, and blood profiles of weaned pigs.