PSIV-20 Growth performance and gastrointestinal responses in Hybrid Toms fed antibiotic free corn-soybean meal diet supplemented with multiple doses of a single strain Bacillus subtilis probiotic.

摘要

Growth performance and gastrointestinal (GI) responses to a single-strain of (SSB; DSM 29784) were investigated using 960 Hybrid Converter Toms. Four iso-caloric and iso-nitrogenous, corn-soybean meal based diets (n=12 reps/treatment) were fed ( ) in a four-phase growout (Starter; d0-28, Grower-1; d29-56, Grower-2; d57-84, and Finisher; d85-126), and treated with either 0, 1.1E+08 (low), 2.2E+08 (mid) or 1.1E+09 (high) cfu /kg. BW, FI and FCR were recorded at the end of each phase. On d 28 and 56, 5 and 3 birds, respectively, were randomly selected and euthanized. The GIT of each bird was weighed and jejunal sections were taken for histomorphology. Compared to the control in the starter phase, the three doses ofSSB increased BWG by 4.5, 5.0, and 4.1%, respectively (P<0.05). BWG of the SSB-treated birds did not differ when compared to the control birds in the grower-2 phase; however, birds fed the low and mid-level of SSB gained more weight than the control in the finisher phase (P<0.05). By the end of the trial, birds fed low level of SSB, were ~560 g heavier than control birds (P<0.05).FCR responses were only observed in the finisher phase, as birds fed low, mid and high level of SSB showed improvements of 5.5, 6.4 and 6.1% over the control (P<0.05). SSB improved small intestine growth in starter phase (P<0.05), but not in grower phase. In the starter phase, villi height and villi:crypt ratio increased in a dose-dependent manner over the control (P<0.05): 16.8, 21.2, and 22.3% for villi height and 10.7, 17.0, and 41.1% for villi:crypt ratio.In conclusion, feeding the strain improved growth in the early phases and FCR in the later phases. Based on the improvement in villi:crypt ratios, the positive effects upon performance are likely linked to a more efficient and stable gut ecology.