Spray-dried plasma ( SDP ) contains immunoglobulins and glycoproteins that possess antibacterial properties. Two floor-pen trials were conducted to determine the efficacy of dietary SDP and bacitracin methylene disalicylate ( BMD ) antibiotic in reducing intestinal colonization by Salmonella Enteritidis ( SE ) in broiler chickens. Experiment 1 was a 2-wk, 3 × 2 factorial design consisting of 6 treatments. Treatment CON consisted of chicks fed unmedicated corn-soybean meal (SBM) basal without SDP. Treatment BMD consisted of chicks given unmedicated corn-SBM basal into which BMD was added at 0.055g/kg diet. Treatment SDP consisted of chicks given unmedicated corn-SBM basal into which SDP was added at 30g/kg diet. Treatments CON-SE, BMD-SE, and SDP-SE consisted of chicks that were given diets similar to CON, BMD, and SDP, respectively, and were each inoculated with 7.46 × 10 8 CFU SE /mL at 1 day of age. Experiment 2 was a 42-day trial that was similar to Experiment 1 in design, except that chicks were placed on fresh clean litter. On d 3, 7, 14, and 28 post-challenge ( PC ), ceca SE concentration was enumerated on xylose lysine tergitol-4 ( XLT4 ) agar. Body weight gain ( BWG ) and feed conversion ratio ( FCR ) were also recorded. Results for d 3 showed that BMD- and SDP-fed chicks had similar ( P > 0.05) cecal SE (3.39 log 10 CFU / g and 3.58 log 10 CFU / g, respectively), but these levels were lower ( P < 0.05) than that of CON-fed chicks (5.68 log 10 CFU / g). A similar trend was observed on d 7 and 14 PC. The BMD- and SDP-fed chicks also had higher BWG and FCR ( P < 0.05) when compared with CON-fed chicks up to d 14. Thereafter, only BMD treatment sustained this growth-promoting effect till d 42 in SE-challenged birds. In conclusion, BMD and SDP showed similar efficacy in reducing cecal Salmonella and in mitigating consequent growth-depressing effect(s) in broiler chicks up to 2 wk of age.

Acquired resistance to in-feed antibiotic growth promoters continues to be an imperative problem in the livestock industries, thereby necessitating continuous pursuit for alternatives. Antimicrobial peptides (AMPs) represent a critical part of the host's innate immune system and have been documented to have immunomodulatory activity. Increasing research evidence suggests that in contrast to antibiotics, AMPs exert broad-spectrum antibacterial activity in a manner that reduces bacterial acquisition of resistance genes. This review summarizes current knowledge on the protective effects of endogenous (natural) AMPs in the gastrointestinal tract of food animals. Factors limiting the efficacy of these AMPs were also discussed and mitigating strategies were proposed.

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In the present study, we determined the effects of long-term exposure to aspirin on the growth and functionality of Lactobacillus rhamnosus. One isolated colony of L. rhamnosus was propagated three times in deMan, Rogosa and Sharpe (MRS) broth and incubated at 37°C. The active strain was then harvested and washed with 0.1% peptone water. Cells were transferred into 9 mL MRS broth containing approximately 6 mg/mL of aspirin, vigorously mixed and incubated for 4 h. The cells were further harvested, transferred into MRS broth and incubated at 37°C. The exposure protocol was repeated for five sequential transfers a week, and the exposed strain cell was surface plated onto MRS agar containing equal amount of aspirin. One isolated colony of aspirin exposed L. rhamnosus from an aspirin containing agar plate was further activated in MRS broth. This procedure was repeated sequentially for 12 consecutive weeks. Bacterial populations, β-galactosidase activity (β-gal), and protein expression were determined. Bacterial cells unexposed to aspirin were used as the control. Our results showed that L. rhamnosus could survive after long term exposure to a sub-inhibitory concentration of aspirin. The average β-gal activity of L. rhamnosus in unexposed cells was 153 ± 2.5 Gal U.; however, β-gal activity was completely inhibited in exposed cells throughout the exposure period. There was approximately 54% more protein expressed in the long term aspirin-exposed strain compared to the short term exposed (4 h) strain as determined by BCA assay. In addition, the SDS-page gel indicated the synthesis of more protein in the exposed L. rhamnosus. The onset of common or chronic illnesses, especially among the elderly population, is often treated with common medications. However, regular the intake of medical drugs such as aspirin could affect beneficial gut microflora. Therefore, foods containing probiotics such as yogurt and other functional foods are important for the maintenance of optimal gastrointestinal health.

The objective of this study was to investigate the survival and growth of L. rhamnosus ATCC 53103 in the presence of aspirin in Lactobacilli MRS (deMan, Rogosa and Sharpe) broth. Bacterial growth was assessed by measuring turbidity, and the population was determined by pour plate method. The minimal inhibitory concentrations (MICs) of aspirin were tested by the standard agar dilution method. The effects of aspirin on β-gal activity were examined using miller units. Our results showed that significant reductions in the population of L. rhamnosus which were dose-dependent. The MIC was 2mg/mL with an inhibitory zone diameter of 10±0.33mm.The average β-gal activity of L. rhamnosus strain in control samples was 150±2.5Gal U. The production of β-gal decreased as the concentration of aspirin increased. Thus, our results demonstrated that aspirin can affect the growth of L. rhamnosus, and this could have an impact on human health.