PSII-1 - Bacillus-based probiotic supplementation to sows and weaned progeny help to support live performance and manage gross lung lesions in a nursery H1N2 Influenza challenge

Abstract: Recent studies have indicated that providing an effective probiotic to dams and their progeny allows the pigs to respond more favorably to viral challenges (Lerner et al., 2020; Bertram et al., 2022). Sixteen pregnant dams (parity 1 to 5) allotted by gestation pen were exposed to one of two treatments: Control (CON) where dams consumed a standard, non-probiotic containing, gestation and lactation diet or Bacillus (BAC) where dams consumed standard diets with a daily top dress applied to achieve 1.65 x 10⁶ CFUs of Bacillus/gram of complete feed from 5 weeks prior to farrowing through lactation. Ninety-six nursery pigs were allotted (48 per treatment group) to the nursery portion of this study at weaning. CON pigs selected for the nursery received non-probiotic containing feed and BAC pigs selected for the nursery received 1.10 x 10⁶ CFUs Bacillus/gram of complete feed for the 3-week nursery period of the study. Pigs were separated into 8 pens with 6 pigs per pen by treatment. Individual pig weights and pen feed intakes were recorded on days 0, 7, 14, and 21. Following 14-days of feed acclimatization post-weaning, all pigs received an H1N2 Influenza viral challenge via intratracheal gavage (Haesebrouck et al., 1986). Clinical signs, including rectal temperatures, respiratory score, abdominal score, and demeanor score we collected daily beginning one day prior to challenge (day 13) through the end of the study. On day 21, following weight collection, all pigs were euthanized, lungs were removed, and each of seven lung lobes (right and left cranial, right and left middle, accessory, and right and left caudal) were scored on percentage of lobes bearing gross (visible) lung lesions (Halbur et al., 1996). Pigs in the BAC group had better F:G ratios during the pre-challenge (1.177 v. 1.309, P < 0.01), post-challenge (1.418 v. 1.633, P < 0.01), and entire growth (1.287 v. 1.464, P < 0.001) periods, compared to those of the CON group. The percentage of pigs in the BAC group with gross lung lesions in the left and right cranial, accessory, and left and right caudal lung lobes was lower than those of the CON group (Table 1). Additionally, total lung lobes with lesions per pig (4.1 v. 5.3, P < 0.001) were lower in pigs in the BAC group. These data indicate that application of a Bacillus-based probiotic (in this case BioPlus® 2B) to sows and subsequently their weaned progeny is associated with better feed efficiency and fewer lung lesions following a challenge with H1N2 Influenza.