Effects of a mixture of Bacillus amyloliquefaciens and Bacillus subtilis on the performance of growing-finishing pigs

The study was conducted to determine the effects of a Bacillus-based probiotic (mixture of spores of Bacillus amyloliquefaciens DSM 25840 and Bacillus subtilis DSM 32324 supplementation on growth performance and health of growing-finishing (GF) pigs. A total of 576 GF pigs with initial body weight (BW) of 23.2 +/- 2.95 kg were allotted to one of two treatments (control diet and probiotic diet). Pigs were blocked by litter origin, BW and sex and allotted to 24 mixed-sex pens (6 entire males and 6 females per pen) per treatment. The GF pigs were fed pelleted diets containing 0 (control diet) or 400 mg/kg (6 x 10(8) CFU per kg feed; confirmed by analysis) of the Bacillus-based probiotic. The diets were supplied ad libitum as dry feed. Pigs were followed fill day 102 after the start of the study. During the grower phase (1-35 days), probiotic supplementation tended to improve the feed conversion ratio (FCR) (P = 0.09). During the finisher phase (35-102 days), probiotic supplementation significantly improved FCR (P = 0.03) and tended to increase the average daily gain (ADG) (P = 0.09). During the overall period (1-102 days), probiotic supplementation significantly improved FCR (P = 0.01). Probiotic supplementation did not affect the number of culled and veterinary treated pigs. The number of treatments due to ileitis (an infection with Lawsonia intracellularis), however, tended to be lower in the probiotic group (7 vs 16; P = 0.07). Most pigs showed normal faecal consistency in the grower phase and the mean pen faecal score during the grower phase was similar in the control group and the probiotic group. In conclusion, feeding GF pigs diets supplemented with 400 mg/ kg of a Bacillus-based probiotic containing a mixture of viable spores (confirmed by analysis before used in this trial) of two specific strains of Bacillus amyloliquefaciens and Bacillus subtilis improved the FCR of the GF pigs during the overall fattening period. Moreover, it tended to decrease the number of veterinary treatments due to ileitis.