Comparison of 3 agar media in Fung double tubes and Petri plates to detect and enumerate Clostridium spp. in broiler chicken intestines.

Clostridium perfringens is an anaerobic, spore-forming bacterium that may lead to necrotic enteritis, resulting in poor feed efficiency and increased mortality in chickens. It is estimated that C. perfringens infects almost 1 million people in the United States every year. The objective of this research was to compare the Fung double tube (FDT) and conventional Petri plates using 3 different media to detect and enumerate Clostridium spp. in chicken intestines. Nine Cobb 500 broilers were randomly selected and euthanized at 21 and 42 d of age for a total of 18 samples. The jejunum and ileum from each broiler were harvested and studied in 2 methods and 3 media combinations, utilizing a 2 × 3 factorial totaling 6 treatments. The 2 methods were FDT and conventional Petri plates, and the 3 media were Shahidi-Ferguson Perfringens (SFP) with egg yolk supplement, polymyxin B, and kanamycin (E); SFP with polymyxin B and kanamycin (P); and SFP with d-cycloserine (C). Enumerations were performed after 24 h of incubation at 37°C. At 21 d, counts using medium C with FDT (4.51 log10 cfu/g) and plates (2.38 log10 cfu/g) were higher (P < 0.05) than using media E or P. On d 42, there were no differences among plate treatments and medium E had the highest counts (0.98 log10 cfu/g). Of all the FDT, medium C (5.35 log10 cfu/g) had the highest counts (P < 0.05), followed by medium P (3.54 log10 cfu/g). This study illustrates that the FDT method is able to enumerate Clostridium spp. at higher levels (P < 0.001) than the conventional Petri plate method; therefore, the FDT should be implemented and further explored.

Interaction of Bacillus species and Salmonella enterica serovar Typhimurium in immune or inflammatory signaling from swine intestinal epithelial cells.

Previous research evaluated a laboratory strain of Bacillus licheniformis (BL) in a model swine epithelium and found it exerted antiinflammatory effects on Salmonella enterica serovar Typhimurium (Sal)-induced secretion of IL-8. The current investigation evaluated the antiinflammatory actions of Bacillus bacteria available commercially as feed additives for the swine industry. Three isolates were obtained from the product, 2 Bacillus subtilis (BS1 and BS3) and 1 BL (BL2). Swine jejunal epithelial IPEC-J2 cells were seeded into wells on permeable membrane supports and allowed to form confluent monolayers. Treatments included apical pretreatment with BL, BS1, BL2, or BS3 for 17 h without Sal, and the same Bacillus treatments but with 10(8) cfu of Sal added in the final hour of Bacillus incubation. Two additional treatments included negative control wells receiving no bacteria (control) and positive control wells receiving only Sal (10 total treatments). After bacterial incubation, wells were washed and fresh medium containing gentamicin was added. Cells were incubated for an additional 5 h, after which apical and basolateral media were recovered for determination of IL-8 and bacitracin. In addition, inserts with epithelial cells that had received Sal were lysed and lysates were cultured to determine treatment effects on Sal invasion. Exposure to Sal alone provoked an increase in IL-8 secretion from IPEC-J2 cells compared with control wells (P < 0.001 for both the apical and basolateral directions). Pretreatment with each Bacillus isolate followed by challenge with Sal reduced Sal-induced IL-8 secretion in both the apical and basolateral compartments compared with wells receiving only Sal (P < 0.001; except for BS3 apical, P < 0.01). The residual presence of bacitracin could be detected only in BL2 and BL2+Sal. Fewer Sal colonies could be cultured from lysates of BL2+Sal than from the Sal, BS1+Sal, and BS3+Sal treatments (P < 0.001). Results indicate that B. subtilis and BL have the ability to intervene in secretion of the neutrophil chemoattractant IL-8 from swine intestinal epithelial cells. This effect on chemokine secretion by gastrointestinal epithelial cells in vitro could not be explained solely by reduced invasion of epithelial cells by Sal.

Effects of dry aging of bone-in and boneless strip loins using two aging processes for two aging times.

This experiment investigated the combined effects of two dry-aging methods (unpackaged and in a bag), two loin-cut styles (bone-in shell loins and boneless strip loins), and two aging times (21 and 28days) on the physical, chemical, sensory, and microbial properties of dry-aged beef. Sections from shell and strip loin were assigned randomly to be aged unpackaged or aged packaged in a bag with high moisture permeability. Weight losses increased with aging time. Shell loins lost more (P<0.05) weight during aging compared with strip loins; dry aging in a bag had less (P<0.05) weight loss than unpackaged aging. There were no differences (P>0.05) in any of the sensory traits between shell and strip loins or dry aging using a traditional method or in a bag. Dry aging in a bag creates positive effects on yields, no negative effects on product quality, and adds flexibility and control of the aging environment.