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In a series of five 17-d replicate trials, a total of 54 cannulated and 12 noncannulated pigs were used to determine the effects of weaning age (17 d or 24 d) on pH, dry matter percentage, aerobic and anaerobic microflora, lactate, and volatile fatty acid (VFA) concentrations in the jejunum, ileum, and cecum of weanling pigs. At -14 d of age, cannulated pigs were surgically fitted with T-cannulas in the jejunum (n = 20), ileum (n = 18), or cecum (n = 16). Upon weaning, cannulated pigs were individually caged in an environmentally controlled room with ad libitum access to a phase starter diet and water. Noncannulated pigs were killed at weaning and samples were collected from the jejunum, ileum, and cecum. Digesta and fecal swabs from cannulated pigs were collected twice weekly. The pH of cecal contents was lower (P < 0.05) and dry matter percentage was greater (P < 0.05) than those of jejunal or ileal contents. Pigs weaned at 24 d of age had increased (P < 0.05) E. coli populations 3 d postweaning compared to preweaning populations, regardless of site of collection, whereas this increase was not observed in pigs weaned at 17 d of age. Unweaned pigs maintained higher (P < 0.05) lactobacilli populations compared to weaned pigs; however, populations declined (P < 0.05) in both groups by 3 d postweaning, with pigs weaned at 24 d of age having lactobacilli populations greater than pigs weaned at 17 d of age. Fecal populations of E. coli and lactobacilli declined (P < 0.05), whereas fecal bifidobacteria populations increased (P < 0.05) postweaning, regardless of weaning age. Concentrations of total fecal anaerobes declined (P < 0.05) in pigs weaned at 17 d of age but were maintained in pigs weaned at 24 d of age. Volatile fatty acid concentrations were greater (P < 0.05) in the cecum than in the jejunum or ileum, and acetic acid concentrations decreased (P < 0.05) postweaning regardless of weaning age. A tendency for L+ lactate concentrations to be greater (P < 0.07) in the ileum and jejunum vs the cecum was observed. Results indicate that weaning and weaning age have significant effects on microbial populations and VFA concentrations. Key Words: Cecum, Ileum, Intestinal Microorganisms, Jejunum, Pigs, Weaning

In three replicate trials, a total of 36 pigs that had been cannulated at the terminal ileum were used to determine the effects of a Saccharomyces cerevisiae culture in a phase feeding program (phase I was d 0 to 7 and phase II was d 8 to 21) on performance, ileal microflora, and short-chain fatty acids in weanling pigs. Pigs were cannulated at approximately 12 d of age, weaned at 17 d of age, and randomly assigned to one of three treatments: 1) a pelleted phase feeding program, 2) a similar program with the inclusion of a live S. cerevisiae culture (1 g/kg), and 3) a nonpelleted feeding program otherwise similar to program 2. Ileal samples were collected at 17, 20, 24, 27, 31, 34, and 38 d of age, and samples were analyzed for total E. coli, streptococci, lactobacilli, yeast, short-chain fatty acids, pH, and dry matter. Performance data were also collected. At 41 d of age, pigs were killed and digesta were collected from various regions of the gastrointestinal tract. Total intake was less for pigs fed the control diet than for pigs fed the yeast diets, and overall gains tended to be greater for pigs fed diets including yeast. Treatment differences were not observed for ileal micro flora or short-chain fatty acids in samples obtained from cannulas or from the various sites of the gastrointestinal tract. Inclusion of a live yeast culture in weanling pig diets affected intake and performance but did not alter tested intestinal micro flora or net concentrations of fermentation products. Key Words: Pigs, Saccharomyces cerevisiae, Intestinal Microorganisms, Volatile Fatty Acids, Ileum

Sows and pigs from 10 commercial swine farms were sampled to determine patterns of resistance of fecal Escherichia coli to five commonly used antibiotics. Before testing, farms were categorized as high or low antibiotic use based on interviews with the respective producers. On each farm, fecal swabs were obtained from five sows at 7 d postpartum and from five pigs from each sow at 7, 35, and 63 d of age. A total of 6,296 E. coli isolates from 750 pig fecal samples and a total of 462 E. coli isolates from 50 sow fecal samples were tested against apramycin, carbadox, gentamicin, neomycin, and oxytetracycline using a standardized disk diffusion test. Percentage of resistant organisms was compared between pigs at the various stages of growth, between sows and their respective pigs, and between farms of high and low antibiotic use. Incidence of resistance was greater (P < .05) in pigs at 35 or 63 d of age compared with 7 d of age for most antibiotics, and patterns differed between high-use and low-use farms. Resistance differed (P < .05) among E. coli from pigs compared to their respective sows for apramycin and carbadox on low-use farms, whereas incidence of resistance on high-use farms differed (P < .05) between sows and pigs for apramycin and oxytetracycline. These data indicate that patterns of antibiotic resistance are dependent on age of pig and level of antibiotic use. Key Words: Antibiotics, Escherichia coli, Sows, Pigs

In three experiments, weanling pigs were used to investigate the effect of feeding .5% galactosyl lactose in a simple corn-soy diet on nutrient digestibility, selected ileal microbial concentrations, fermentation acids, and performance. In Exp. 1, 20 21-d-old weaned pigs in two replicate trials were fed either a 19% CP corn and soybean meal diet or a similar diet containing .5% galactosyl lactose. Feces and urine were collected over a 3-wk period to determine apparent CP and energy digestibilities. Apparent digestibilities of CP and energy were not different between treatments. In Exp. 2, 24 14-d-old nursing pigs were cannulated at the terminal ileum and fed the diets described above after weaning at 21 d of age. Ileal samples were collected at 20, 23, 27, 30, 34, 37, and 41 d of age. Samples were assayed for VFA, lactate, and selected microflora. Ileal fermentation acid concentrations and selected microflora were affected by age of pig but were not different between feed treatments. In Exp. 3, 91 21- to 24-d-old weaned pigs were fed the control and test diets already described; intake, BW gain, and feed efficiency were determined for 9 wk after weaning. Intake was greater in pigs fed galactosyl lactose, but ADG and gain/feed did not differ between treatments. Inclusion of galactosyl lactose in weanling pig diets did not affect protein or energy digestibility, microflora, short-chain fatty acids, or performance of young pigs. Key Words: Pigs, Oligosaccharides, Volatile Fatty Acids, Ileum

Studies were conducted to determine the effect of galactan on the colonization of E. coli and lactobacilli and ileal pH and volatile fatty acid production in the digestive tract of the weanling pig. In each of two replicate trials, eight 21-d-old nursing pigs were cannulated in the terminal ileum. After a 7-d recovery period, the pigs were weaned and randomly assigned to two test diets: 1) a corn-soybean meal-based control diet and 2) a similar diet containing 1% galactan. On d 1 after weaning, all pigs were orally subjected to [K88.sup.+] E. coli (2 x [10.sup.9] colony forming units). Ileal digesta samples were collected on d 0, 2, 4, 6, 8, and 10 after weaning and assayed for total E. coli, [K88.sup.+] E. coli, lactobacilli, pH, and VFA. At the end of the trials, the pigs were killed and digesta samples were collected from the stomach, duodenum, cecum, and colon. Assays similar to those performed on the digesta samples collected from ileal cannulas were performed. Pigs fed 1% galactan had lower (P < .10) ileal pH, lower (P < .05) total E. coli on d 6 and 8, and lower (P < .05) [K88.sup.+] E. coli concentrations in the ileum than pigs fed the control diet. There were no differences in ADG or gain:feed ratio between diets. The V-FA concentrations were not different in the ileum between diets. The VFA were higher (P < . 10) on d 0 than on any other day of the study. Acetate and isobutyrate concentrations were lower ( P < . 10) in the cecum in pigs fed 1% galactan. Galactan included in the feed on a 1% DM basis decreased pH and E. coli in the small intestine of newly weaned pigs. Key Words: Escherichia coli, Pigs, Volatile Fatty Acids, Ileum, Galactans

Escherichia coli strains from sows and pigs exhibit multiple antibiotic resistance mechanisms. This was evident in an experiment comparing patterns between pigs of various ages and extent of antibiotic use. It was found that resistance patterns differ between farm types and pigs of varying ages, implying that pig age and degree of antibiotic use exert an influence on antibiotic resistance of fecal Escherichia coli.