Diet Modification to Reduce Fecal Excretion of Nitrogen and Phosphorus in Growing-Finishing Pigs

An experiment was conducted to determine whether brewers rice can replace all corn in diets for swine and reduce fecal excretion of Nitrogen (N) and Phosphorus (P) without compromising performance and carcass quality of growing-finishing pigs. Sixteen Yorkshire x Duroc x Hampshire crosses (BW = 77±2.5 kg) were randomly assigned to either corn/soybean meal (CSM; control) or brewers rice/soybean meal (RSM) diet. Both diets were formulated to contain 14% CP. The RSM pigs had a greater reduction (p<0.001) in daily fecal loss of N (0.007 Vs. 0.011 kg pig^-1) and P (0.007 Vs. 0.008 kg pig^-1), lower (p<0.001) fecal output (0.171 Vs. 0.322 kg pig^-1), than CSM pigs. Compared with CSM pigs, RSM pigs gained faster (0.712 Vs. 0.581 kg pig^-1 per day; p<0.01) and had better gain to feed ratio (0.30 Vs. 0.25; p<0.01). Furthermore, RSM pigs had greater (p<0.001) Apparent Total Tract Digestibility (ATTD; 91.5 Vs. 84.1%). Diet did not (p>0.10) affect carcass yield and Loin Eye Area (LEA), however, RSM pigs tended (p<0.10) to lay more back fat than CSM pigs. In conclusion, brewers rice can replace all corn in diets for growing-finishing pigs, reduce fecal excretion of N and P, increase pig performance with no effect on carcass quality. Consequently, feeding brewers rice instead of corn may help reduce environmental pollution attributed to excessive fecal excretion of N and P in growing-finishing pigs.