PSXV-7 - Nutrient Digestibility Evaluation in Finisher Pigs from Diverse Feed Efficiency Groups

Abstract: Feed efficiency (FE) is a critical trait in swine production to improve the overall production efficiency and profitability and is an important goal for pig breeding companies. FE is a complex trait involving utilization and storage of dietary nutrients in different organs, and more especially in skeletal muscles. However, whether nutrient digestibility in the pig is altered by genetic selection for FE is less clear. Thus, this study investigated the variation in apparent total tract nutrient digestibility (ATTD) in finisher boars selected for high (HFE) or low (LFE) FE within a Large White dam and sire line. A total of 130 boars were selected at 23 wk of age based on their genomic-enabled breeding value for FE and fed ad libitum a corn-soybean meal-based diet using feeding stations that recorded individual feed intake and body weight. Fecal and diet samples were analyzed for dry matter, neutral detergent fiber, acid detergent fiber, crude protein (CP), energy, ash, phosphorus, and calcium to determine ATTD using acid-insoluble ash as an indigestible marker. There was no difference in ATTD values between genetic lines (P > 0.10). However, HFE pigs had greater (P = 0.03 ATTD of CP compared with LFE pigs. Based on the estimated protein deposition and the average feed intake one week before sampling, calculated dietary digestible lysine content diet met the requirements for the average pig. However, HFE pigs had a reduced feed intake, implying that they might have experienced a shortage of lysine in the diet. It is unclear whether the improved ATTD of CP was due to a lysine-shortage or differences in genetic merit for FE.