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Supplementing sows or their litters with a direct fed microbial feed additive decreases fecal shedding of bacterial pathogens and increases litter performance in sows naturally infected with porcine reproductive and respiratory syndrome virus (PRRS)
Data from a previous study indicated that fecal shedding of pathogens by sows was reduced and the number of pigs weaned per litter was increased when Tri-Lution (T-L; Agri-King, Inc.), a synbiotic blend of pre- and probiotics, was fed to PRRS-negative sows. The two studies reported herein were conducted to further evaluate the effects of feeding T-L to sows or their litters. Both studies occurred during naturally-occurring PRRS outbreaks. The first study was conducted to determine whether a daily top-dress of 60g T-L onto pig creep mats during lactation would 1) reduce fecal shedding of bacterial pathogens in piglets, and 2) increase the number of pigs weaned per litter. At farrowing, a total of 78 individually-housed litters were blocked by their dam’s parity and allotted randomly to 1 of 2 treatments (negative control or T-L). Fecal samples were collected from a subset of 36 litters (19 d old pigs) and cultured for bacterial pathogens (cfu/g feces). Treatment of litter creep mats with T-L increased (P<0.01) the number of pigs weaned per litter (10.46 vs. 8.74) and reduced (P<0.01) fecal shedding of coliforms (log 9.25 vs. 10.01) and E.coli (log 9.13 vs. 9.92), and tended (P<0.06) to reduce fecal populations of Clostridia (log 6.54 vs. 7.14). In the second study, third-trimester, parity-one and parity-two sows (n = 160) were blocked by parity and randomly assigned to 1 of 2 daily treatments to determine the effect of T-L on 1) the number of pigs weaned per litter and 2) serum concentrations of neutralizing antibodies against PRRS. From d 84 of gestation until weaning, treatments to sows consisted of either a negative control or a daily, 30-gram oral dose of T-L. All sows were fed the same basal diet. Serum was collected from a subset of 32 sows following natural exposure to the farm’s circulating PRRS virus and subsequent vaccination with live PRRS virus. The number of pigs weaned per sow was increased (P<0.02) in sows fed T-L (7.40 vs. 5.81). Neutralizing antibody titer against PRRS was not increased (P<0.27) in sows treated with T-L (95.9 negative control vs. 137.6 T-L). In summary, these results indicate that feeding T-L during a PRRS outbreak reduced fecal shedding of bacterial pathogens and improved piglet survivability. It is hypothesized that favorable modifications to the gastrointestinal microbiota from feeding T-L strengthened the intestinal immune response against microbial pathogens, leading to improved piglet survivability.
Keywords: Probiotic, PRRS