161 Effect of High- and low-Fiber Diets on Growth Performance in Growing-Finishing Pigs Selected for low or High Feed Efficiency

Understanding the effects of high- and low-fiber diets on the growth performance of pigs with different feed efficiencies will help the livestock industry develop new strategies to reduce the costs of pig production. In this study, 18 Landrace × Large White sows with high and low estimated breeding value on feed conversion ratio (EBV-FCR) were inseminated with semen from Large White with known EBV-FCR to produce 9 litters of low feed efficiency pigs and 9 litters of high feed efficiency pigs. A total of 94 growing pigs with low or high feed efficiency were fed a low-fiber (3% crude fiber) or high-fiber (6% crude fiber) content diet in a 2 × 2 factorial arrangement for 70 days. Pigs fed a high-fiber diet presented higher body weight (BW) on day 70 (P < 0.05). High feed efficiency pigs presented lower average daily feed intake (ADFI) and feed conversion ratio (FCR) than low feed efficiency pigs from day 0 to 70 (P< 0.05). There was an interaction between fiber and feed efficiency group on average daily gain (ADG;P < 0.05) and FCR (P < 0.05) from day 0 to 35. High feed efficiency pigs fed a high-fiber diet presented lower FCR than low feed efficiency pigs fed a low-fiber diet (P< 0.05). Low feed efficiency pigs fed a low-fiber diet showed the lowest ADG (P< 0.05). Regardless of efficiency groups, pigs fed a high-fiber diet presented higher ADG and lower FCR than pigs fed a low-fiber diet from day 42 to 70 (P< 0.05). These results suggest that high feed efficiency pigs can present lower FCR and ADFI without reducing final BW and ADG. Feeding a high-fiber diet can increase ADG and reduce FCR in the later stages of the experiment.