Effects of increasing dietary fiber on digestibility, performance and carcass characteristics: II. prepuberty and puberty gilts

Abstract

Female pigs that are intended to be used as sows have to follow a dietary plan that restricts caloric intake. Roughages due to their high content of fiber are low energy sources for swine. This feeding strategy gets around the excessive body fat accumulation. Aiming to study these aspects, prepuberty and puberty gilts were fed isoenergetic and isoproteic rations containing 0; 6.6; 13.2 and 19.8% of neutral detergent fiber (NDF), obtained with the inclusion of coast-cross hay. Twenty crossbred gilts were assigned to a randomized block design experiment which lasted 97 days. Then, the animals were slaughtered. Increment of NDF reduced linearly body weight gain (0.675; 0.607; 0.525; 0.483 g/day); body weight on first physiological heat onset (118.0; 114.0; 102.2; 98.2 kg) and worsened feed conversion (3.6; 4.0; 4.7; 5.3). It was observed a quadratic response on the backfat thickness (3.28; 3.34; 2.82; 1.74 cm). There was no effect over the age of first physiological heat onset (203 days) and hot carcass yield; however, quadratic response for cold carcass yield was obtained (79.79; 80.24; 79.58; 77.40%) and lean meat yield (54.45; 54.35; 55.51; 58.31%). Increasing content of NDF reduced linearly dry matter digestibility (76.23; 67.23; 55.83; 55.73%) and NDF digestibility (56.63; 44.24; 34.17; 39.12%); there were quadratic responses to crude protein (72.16; 64.46; 53.52; 62.74%) and crude energy digestibilities (71.95; 61.23; 49.21; 53.81%). Gilts body condition was not affected by continuous offering of fibrous ration during prepuberty and puberty phases.