Effect of dietary supplementation with Lactobacillus plantarum on growth performance, fecal score, fecal microbial counts, gas emission and nutrient digestibility in growing pigs

The objective of this study was to evaluate the effect of dietary supplementation with Lactobacillus plantarum (L. plantarum) on the growth performance, fecal score, fecal microbial counts, gas emission, and nutrient digestibility in growing pigs. A total of 180 growing pigs (Duroc x (Landrace x Yorkshire)) with average initial body weight (BW) of 24.72 ± 1.731 kg were randomly allocated to four treatments with nine replications of five pigs per pen (three gilts and two barrows) in a 6-week trial experiment. Dietary treatments were as follows: CON, control treatment; LP1, CON + 0.15 g (0.18 ×10−6 CFU)/kg L. plantarum; LP2, CON + 0.30 g (0.36 ×10−6 CFU)/kg L. plantarum; LP3, CON + 0.45 g (0.54 ×10−6 CFU)/kg L. plantarum. The increasing dose of L. plantarum supplement linearly increased the BW of growing pigs at weeks 3 and 6 (P = 0.028, P = 0.037, respectively). Also, pigs fed diets supplemented with L. plantarum linearly increased the average daily gain (ADG) (P = 0.037) and gain-to- feed ratios (G:F) (P = 0.027) during the overall experimental period. Dietary inclusion of L. plantarum supplement linearly reduced (P = 0.045) the concentration of fecal ammonia (NH3) emissions in LP group. While, pigs fed graded level of L. plantarum supplementation linearly increased (P = 0.004) the Lactobacillus population at the end of the trial. Additionally, apparent total tract digestibility (ATTD) of dry matter (DM) was linearly increased (linear effect: P = 0.045) in LP group pigs. However, no differences were found on average daily feed intake (ADFI), fecal score, Escherichia coli (E. coli) counts, total mercaptan (R.SH) and hydrogen sulfide (H2S) concentrations in feces, and the ATTD of nitrogen. Our results indicated that dietary supplementation of 0.45 g (0.54 ×10−6 CFU)/kg L. plantarum could be effective to improve the growth performance, fecal Lactobacillus counts, nutrient digestibility of DM, and reduce fecal NH3 concentration in growing pigs.