Effect of different level of fiber and protein on growth performance and fecal characteristics of weaned pigs

Abstract Text: A total of 96 weanling pigs (7.4 ± 1.2 kg) were used in 5-wk growth assay to determine the growth performance, fecal score, fecal microbial shedding and ammonia emissions with dietary manipulation of fiber and protein content. Pigs were allotted to dietary treatments based on their BW in a 2 x 2 factorial, with main effects of fiber concentration (low = 65 and 125g/kg in phase 1 and 2 and high = 100 and 140 g/kg in phase 1 and 2) and CP concentration (low = 170 g/kg vs high = 200 g/kg). There were 6 pigs/pen and 4 pens/treatment. The composite fecal sample (1 g) from each pen was diluted with 9 ml of 1% peptone broth and homogenized. The E. coli and lactobacilli colonies were counted immediately after removal from the incubator and Lactobacilli:E. coli ratio (L:C) was calculated. A gas sampling pump (Gastec Corp., model GV-100; Gastec detector tube No. 3M and 3La for NH₃) was utilized for gas detection. All data were analyzed according to a 4 × 4 replicated Latin square design using the GLM procedure of SAS (SAS, Cary, NC), with pen serving as the experimental unit. Treatment differences were considered significant at a level of 0.05. During the first phase of this experiment, pigs fed high protein and high fiber diet grew faster (P < 0.05) than controls, and pigs fed high fiber and low protein diet consumed more (P < 0.05) than control pigs during the second phase. There was no difference (P > 0.05) in fecal score among the treatments, but feces taken from pigs fed high fiber had lower (P < 0.05) concentrations of E. coli and a higher L:C ratio (P < 0.05). Ammonia in the feces was increased (P < 0.05) continuously from d 1 to 5 and decreased (P < 0.05) after d 5 of the experiment. The level of ammonia was higher (P < 0.05) in the feces of pigs fed high protein and high fiber diet (P < 0.05) compared with control pigs. In conclusion, the results of this study indicate that dietary manipulation influences bacterial counts and ammonia emission in the feces as well as growth performance during the post-weaning period. Thus, high protein and moderate fiber content in the diet may have beneficial effects for the weaning piglets.

Keywords: Fiber, protein, weanling pigs