A study was conducted to determine if sampling rumen contents via a ruminal cannula or oral lavage tube would yield similar denaturing gradient gel electrophoresis profiles of the bacterial community. Two species of ruminally cannulated animals were used for this study (cattle, n = 2; sheep, n = 3). All animals were allowed ad libitum access to feed. Cattle were fed baled unprocessed sorghum-sudan hay (12% CP, 68% NDF; DM basis), whereas sheep were maintained on chopped alfalfa (18% CP, 40% NDF; DM basis). Ruminal fluid was collected (approximately 20 mL) once per week for 3 wk from each animal using a poly tube equipped with a suction strainer with a hand-held suction pump through the rumen cannula or oral cavity. The denaturing gradient gel electrophoresis analysis demonstrates that yield of bacterial diversity was not different between the 2 sampling methods (P = 0.73). When samples were grouped according to band pattern similarity, groups were most stable according to individual animal and species rather than sampling method. Total VFA and molar proportions of individual VFA did not differ by sampling method (P> 0.40). Additionally, rumen ammonia concentrations were similar for both sampling methods (19.3 vs. 19.1 mM +/- 8.0 for cannula vs. lavage, respectively; P = 0.98). These data indicate that rumen samples collected via oral lavage or rumen cannula yield similar results. This knowledge will allow sample collection from a greater population of animals and an ability to maintain the value of research livestock that can be lost due to the surgical implantation of a ruminal cannula.

Cattle grazing dormant western rangelands may have a high ruminal acetate to propionate ratio (A:P) and may have low tissue clearance of acetate. Increasing propionate production could shift this ratio and improve animal performance. In Exp. 1, the effect of Propionibacterium acidipropionici P169 (PA) on forage digestibility and VFA production was evaluated in vitro using 2 substrates: 100% dormant warm-season grass extrusa and 50% sorghum-Sudan hay with 50% ground corn (DM basis). The objective of Exp. 2 was to evaluate the effect of PA or calcium propionate supplementation on digestibility, ruminal fermentation, acetate clearance, and BW change. Twelve 2-yr-old, pregnant Brangus heifers (BW = 416 ± 85 kg) were assigned to 1 of 3 treatments. All cattle were fed a basal ration of Old World Bluestem hay (Bothriochloa ischaemum; 5.8% CP and 76.5% NDF, DM basis) at 1.5% BW from d -10 to d 49. Treatments included a protein supplement (CON; 36% CP and 35% RUP, DM basis; 454 g/animal fed twice daily), CON plus 6 × 10(10) cfu PA/animal (BACT), and CON plus 80 g calcium propionate (PROP). After initiation of treatments (d 0), rumen fluid was collected via oral lavage every 3 d and analyzed for VFA, pH, and ammonia. Glucogenic potential of treatments was evaluated with an acetate tolerance test on d 49. In Exp. 1, PA addition increased (IVDMD; P < 0.001) and total VFA (P < 0.001) of 100% dormant warm-season grass extrusa but not 50% sorghum-Sudan hay with 50% ground corn (P ≥ 0.28). The addition of P169 decreased (P < 0.001) acetate, increased propionate (P < 0.001), and decreased A:P ratio (P < 0.001) for both substrates. In Exp. 2, total tract OM and NDF digestibility and ruminal pH, total VFA, and acetate did not differ (P ≥ 0.13) among treatments. Propionate concentration was least (P = 0.001) for CON, intermediate for P169, and greatest for PROP. Conversely, A:P ratio was greatest (P < 0.004) for CON, intermediate for P169, and least for PROP. Acetate clearance did not differ (P = 0.69) among treatments. Propionibacterium acidipropionici P169 increased IVDMD and total VFA of low-quality forage. Supplementation with PA and calcium propionate salts increased propionate and decreased A:P in the rumen. Supplementation of PA represents a potential way to increase ruminal propionate concentration when dormant forages are fed.

Campylobacter spp. commonly cause gastrointestinal illness in humans. Poultry meats have long been considered the predominant source of these infections, but few in-depth Campylobacter source attribution studies have been completed. We analyzed more than 1,300 Campylobacter isolates recovered from a number of animal and food sources, including dairy and beef cattle, pigs, poultry, and retail poultry meat, and compared them with Campylobacter isolates recovered from human clinical samples. Each isolate was subtyped using pulsed-field gel electrophoresis (PFGE) with SmaI and queried against the Centers for Disease Control and Prevention PulseNet database to identify human isolates with indistinguishable patterns. Half (49.5%) of the PFGE patterns from poultry animal and retail meat isolates were indistinguishable from patterns of at least one human isolate. Among the isolates from beef and dairy cows, 56.6 and 65.0%, respectively, of their PFGE patterns were indistinguishable from those of human isolates. Only a small portion of the PFGE patterns of Campylobacter isolated from pigs (9.5%) were found to have PFGE patterns in common with human isolates. These data imply that cattle may be larger contributors to Campylobacter infections than previously recognized and help further our understanding of potential sources of human campylobacteriosis.

Symbiosis between the bobtail squid Euprymna scolopes (Mollusca: Cephalopoda) and Vibrio fischeri bacteria has been a well-studied model for understanding the molecular mechanisms of colonization and adherence to host cells. For example, pilin expression has been observed to cause subtle variation in colonization for a number of Gram-negative bacteria with eukaryotic hosts. To investigate variation amongst pil genes of closely related strains of vibrios, we amplified pil genes A, B, C and D to determine orientation and sequence similarity to other symbiotic vibrios. The pilA gene was found to be upstream from all other pil genes, and not contiguous with the rest of the operon. The pilB, pilC and pilD loci were flanked at the 39 end by yacE, followed by a conserved hypothetical gene. DNA sequences of each pil gene were aligned and analysed phylogenetically using parsimony for both individual and combined gene trees. Results demonstrate that certain pil loci (pilB and pilD) are conserved among strains of V. fischeri, but pilC differs in sequence between symbiotic and free-living strains. Phylogenetic analysis of all pil genes gives better resolution of Indo-west Pacific V. fischeri symbionts compared with analysis of the 16S rRNA gene. Hawaiian and Australian symbiotic strains form one monophyletic tree, supporting the hypothesis that V. fischeri strain specificity is selected by the geographical location of their hosts and is not related to specific squid species.

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