A 28-d experiment evaluated the growth performance, acute-phase response, and bacterial shedding patterns in pigs (n = 108; initially, 38.7 ± 6.7 kg) fed 6 treatment diets, including a control diet with no antimicrobial agents (CON), a positive control diet containing chlortetracycline, 100 mg/kg (CT), a diet containing anti-Salmonella Typhimurium bacteriophage, 3 × 10(9) plaque-forming units/kg of feed (ASB), Lactobacillus plantarum CJLP56, 6.5 × 10(8) cfu/kg of feed (LP), 0.2% microencapsulated organic acids (MOA), or 5% fermented soybean meal (FSM). Pigs were fed the diets for 2 wk before and 2 wk after challenging orally with Salmonella enterica serotype Typhimurium (SalT). Before bacterial challenge, ADFI was similar in all groups. After SalT challenge, ADFI of CON pigs was less (P < 0.05) than all other groups. Before challenge, pigs on MOA, FSM, and CT diets had greater (P < 0.05) ADG and G:F than CON pigs. After challenge (wk 3 to 4) and during the overall experimental period (wk 1 to 4), ADG of all treatment groups and G:F of all treatment groups except the LP group were greater (P < 0.05) than those of CON pigs. Relative to all other treatments, CON and LP pigs had greater (P < 0.05) bacterial shedding scores on d 7 after SalT challenge. At d 14 postchallenge, shedding scores declined (P < 0.05) in all treatment groups compared with CON pigs. Serum haptoglobin for all treatment groups increased from d 0 concentrations on d 6 postchallenge and declined to prechallenge concentrations on d 13 (P < 0.05). Circulating IGF-I concentrations declined from 2 to 6 d postchallenge and increased again by d 13 in ASB and LP groups, did not decline in FSM and CT groups, and continuously declined through d 13 in CON and LP groups (P < 0.05). However, in MOA group, IGF-I concentrations declined from preinfection concentrations on d 2, increased on d 4, and declined again until d 13 (P < 0.05). The serum concentrations of the cytokines IL-6 and IL-1β were not generally affected by SalT challenge. In conclusion, acute infection of growing pigs with SalT was associated with short-term febrile responses in most pigs and reductions in ADFI and ADG of CON pigs. Compared with the CON diet, ASB, FSM, and MOA diets had a similar benefit to the antibiotic-supplemented diet in improving the performance of growing pigs, especially after bacterial challenge. However, further work needs to be done to better understand their mode of action in this class of pigs.

The purpose of the present study was to evaluate the effect of diets containing Lactobacillus plantarum CJLP243 on the growth and cytokine response of weaning pigs (Sus scrofa) challenged with enterotoxigenic Escherichia coli (ETEC). In a 28-d experiment (14 d before and 14 d after challenge), a total of 108 pigs at 20 ± 1 d of age were allotted to 1 of 6 diets. These were a control diet without ETEC challenge (CON) and 5 treatment diets with ETEC challenge, including a control diet with ETEC challenge (negative control, NC); a positive control diet containing antibiotics (PC); control diet plus (10(8), 10(9), or 10(10)) cfu/kg L. plantarum CJLP243 (T1, T2, and T3, respectively). After challenge, NC showed the least ADFI, whereas PC and T3 had the greatest ADFI (P = 0.002). The ADG of PC, T2, and T3 were greater (P = 0.001) than that of CON, NC, and T1 during wk 1 to wk 2. During wk 3 to wk 4, a marked decline was seen in NC (P = 0.001) compared with CON, whereas PC and T3 showed increased ADG (P = 0.001). The overall ADG of PC and T3 were greater (P < 0.001) than the remaining groups. The PC and T3 had the greatest G:F during the second 2 wk (P = 0.002), and the overall 4-wk experimental period (P = 0.003). At 3 h after challenge, all groups except CON had greater rectal temperatures (RT; P < 0.05). The RT decreased to prechallenge temperatures at 9 h (PC and T3), 24 h (T1 and T2), and remained increased until d 7 in NC. At 7 and 14 d postinfection, the number of animals detected positive for ETEC by PCR assay was the greatest in NC; however, the PC group had the fewest ETEC-positive animals (P < 0.05), which was similar to T3. All challenged pigs, except T2, had greater concentrations of serum haptoglobin compared with CON, with the greatest concentration observed in NC (P < 0.001). Challenged pigs had increased serum concentrations of tumor necrosis factor alpha (TNF-α) 3 to 48 h postinfection, with the greatest concentration of TNF-α at 48 h observed in NC (P < 0.05). Similarly, greater (P < 0.05) serum concentrations of interferon-γ were observed for 9 h (T1 and T3), 24 h (T2 and PC), and 48 h (NC) postinfection. The serum concentration of IL-6 increased (P < 0.05) for 3 h in T3 and 24 h in NC. In conclusion, our findings suggest that L. plantarum CJLP243, at a concentration of 10(10) cfu/kg, may serve as a potential alternative to antibiotic supplementation to improve the growth and health performance of weaning pigs, especially during acute inflammation of the gut after bacterial infections.

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