Sequence analysis and characterization of pOM1, a small cryptic plasmid from Butyrivibrio fibrisolvens, and its use in construction of a new family of cloning vectors for Butyrivibrios.

As a preliminary step in the development of vector systems, we have isolated and begun to characterize small, cryptic plasmids from several strains of the rumen bacterium Butyrivibrio fibrisolvens. We present here the complete nucleotide sequence of Butyrivibrio plasmid pOM1, which was isolated from B. fibrisolvens Bu49.

Group-specific 16S rRNA hybridization probes for determinative and community structure studies of Butyrivibrio fibrisolvens in the rumen.

Oligonucleotide probes covering three phylogenetically defined groups of Butyrivibrio spp. were successfully designed and tested. The specificity of each probe was examined by hybridization to rRNAs from an assortment of B.

A solvent-based fixative for electron microscopy to improve retention and visualization of the intestinal mucus blanket for probiotics studies.

Samples of pig small intestine, cecum, and large intestine were prepared for scanning electron microscopy (SEM), concentrating on mucus blanket retention and visualization. Samples were fixed using three aqueous-based fixatives which included a standard glutaraldehyde fixative alone as the control and the standard fixative formulation with either ruthenium red or alcian blue added and using one solvent-based fixative, osmium tetroxide dissolved in FC-72 (a degreasing fluorocarbon solvent produced by 3M Canada, Inc.), which had been successfully used by Sims et al.

The interplay of feeding and genetics on heifer rearing and first lactation milk yield: a review.

Weight gain of young dairy replacement heifers, even over several months, is highly variable, lowly heritable, and a poor indicator of either weight at calving or first lactation milk yield. Voluntary forage consumption is much less variable, more heritable, and a better predictor of weight at calving and milk yield. Weight at calving is highly heritable but not correlated genetically with milk yield.

The influence of complex carbohydrates on Salmonella typhimurium colonization, pH, and density of broiler ceca.

Salmonella typhimurium colonization, pH, and density of ceca were measured in 3-, 5-, and 6-wk-old broilers fed either a control ration or rations with added fructooligosaccharides (FOS) or lactose derivatives (LD). The purpose was to compare dietary crude FOS from Jerusalem artichokes with refined FOS and two LD for ability to reduce Salmonella colonization as determined by semi-quantitative procedures. Chicks were challenged commencing at 5 d, by exposure to chicks orally infected with S.

Isolation and characterization of a bacteriocin (Butyrivibriocin AR10) from the ruminal anaerobe Butyrivibrio fibrisolvens AR10: evidence in support of the widespread occurrence of bacteriocin-like activity among ruminal isolates of B. fibrisolvens.

Forty-nine isolates of Butyrivibrio fibrisolvens and a single isolate of Butyrivibrio crossotus were screened for the production of inhibitors by a deferred plating procedure. Twenty-five isolates produced factors which, to various degrees, inhibited the growth of the other Butyrivibrio isolates. None of the inhibitory activity was due to bacteriophages.

Association of genetic variants of bovine growth hormone with milk production traits in Holstein cattle.

Gene and genotype frequencies of alleles, identified by PCR/RFLP technology, at leucine 127/valine127 (L/V) and C/D loci of the growth hormone gene of Ayrshire, Holstein and Jersey breeds were determined. The frequency of the V allele at the L/V mutation locus was 0.29, 0.

Toxic effects of deoxynivalenol on ribosomes and tissues of the spring wheat cultivars Frontana and Casavant.

The toxic effects of the Fusarium graminearum trichothecene toxin deoxynivalenol were determined on ribosomes and leaf tissues of the fusarium head blight-resistant spring wheat cultivar Frontana and the susceptible spring wheat cultivar Casavant. The use of a poly-U-directed 14C-phenylalanine and deoxynivalenol ribosome-binding assays provided evidence of resistance to the protein-synthesis inhibition effects of deoxynivalenol in the head blight-resistant cultivar Frontana. This is probably due to the existence of a mutation in the peptidyl transferase.

Effect of intraperitoneal infusion of deoxynivalenol on feed consumption and weight gain in the pig.

The mycotoxin deoxynivalenol (DON) is well documented to cause reduced feed consumption (FC) and weight gain (WG) rates in sensitive animal species. In the present study, the effect of DON on pigs when ingested as a DON-spiked diet was compared with toxin administered by a continuous-delivery osmotic pump that was implanted intraperitoneally (i.p.

Effects of protein source and amino acid supplementation on plasma cholesterol in guinea pigs.

The effects of three dietary protein treatments were compared on cholesterol content of plasma lipoprotein fractions and oxidative status of liver lipids in adult guinea pigs. All diets were adequate in soluble dietary fiber and well-balanced in fatty acids providing 30% of total energy. After seven weeks dietary treatments, casein compared to soy protein increased cholesterol in a sub-fraction of LDL (low density lipoprotein) with larger molecular weight and in a combination of this sub-fraction of LDL plus VLDL (very low density lipoprotein) taken together.

Bioavailability of vitamin E compounds and the effect of supplementation on release of superoxide and hydrogen peroxide by bovine neutrophils.

The effects of daily supplementation of 1000 IU of d-alpha- or dl-alpha-tocopherol acetate to Holstein cows from drying off to 8 wk after calving were studied 1) to compare the bioavailability of d-alpha- and dl-alpha-tocopherol acetate by monitoring vitamin E concentrations in plasma, red blood cells, and neutrophils and 2) to determine the effect of d-alpha- and dl-alpha-tocopherol acetate supplementation on O2- and H2O2 release by neutrophils. Supplementation with d-alpha- or dl-alpha-tocopherol acetate increased vitamin E concentrations in blood plasma, red blood cells, and neutrophils; the d-alpha form was more effective than was the dl-alpha form. Supplementation with d-alpha- or dl-alpha-tocopherol acetate had no effect on the release of O2- and H2O2 by neutrophils, suggesting no harmful effects on surrounding tissues from oxygen-free radicals produced by neutrophils.

Are ruminal bacteria armed with bacteriocins?

The production of toxic compounds or antibiotics is a common component of intermicrobial competitive interactions, and many of these toxins have been adopted and adapted for the control of microbial populations. One class of these toxins, the bacteriocins, is a heterogeneous group of proteinaceous antibiotics that often display a high degree of target specificity, although many have a very wide spectrum of activity. To date, only limited information is available concerning the occurrence of bacteriocins among ruminal isolates or the sensitivity of ruminal microorganisms to exogenous bacteriocins.

Long range-inverse PCR (LR-IPCR): extending the useful range of inverse PCR.

The inverse PCR technique (IPCR) has proven to be very useful for the amplification of uncharacterized stretches of DNA upstream or downstream of regions that have already been cloned and sequenced. In practice, however, chromosome walking using standard IPCR is often a slow, repetitive process because only small DNA fragments are effectively amplified. The development of long and accurate PCR methodology has greatly expanded the range of DNA fragment sizes that is amenable to amplification by conventional PCR.

Concentrations of salinomycin in eggs and tissues of laying chickens fed medicated feed for 14 days followed by withdrawal for 3 days.

Laying chickens were fed medicated feed containing various concentrations of sodium salinomycin (SAL) for 14 days followed by a 3 day withdrawal period. Eggs, collected during treatment and withdrawal, tissues and ovarian yolk of birds slaughtered after 0, 1, and 3 days' withdrawal were extracted and analysed by high performance liquid chromatography (HPLC). Tissues, ovarian yolk and freeze-dried egg albumen and yolk were extracted with acetone, followed by partitioning with petroleum ether and HPLC analysis.

The role of tryptophan in DON-induced feed rejection.

Deoxynivalenol (DON, vomitoxin) commonly produced by Fusarium fungi can alter feeding behaviour of pigs and other farm animals. The effects of dietary tryptophan (TRP, precursor of brain amine serotonin) in combination with DON were examined in mice to determine if TRP can modulate DON toxicity. Results indicated that brain TRP can be influenced by dietary TRP, but no evidence of TRP potentiating DON toxicity was observed.

16S rDNA analysis of Butyrivibrio fibrisolvens: phylogenetic position and relation to butyrate-producing anaerobic bacteria from the rumen of white-tailed deer.

Complete 16S rDNA sequences of six strains of Butyrivibrio fibrisolvens, including the type strain (ATCC 19171), were determined. The type strain was found to have less than 89% sequence similarity to the other isolates that were examined. The five plasmid-bearing strains formed a closely related cluster and three of these strains (OB156, OB157 and OB192) were very highly related (> 99%), indicating that they are isolates of the same genomic species.

Prediction of heterosis from DNA fingerprints in chickens.

To assess the value of DNA fingerprints for the prediction of heterosis in chickens, retrospective analyses of data from three crossbreeding experiments and DNA fingerprints (DEP) of parental strains were conducted using two minisatellite and one middle-repetitive DNA probes. DEP bands were assessed on pooled DNA samples of 10-15 individuals per parental genetic group. The number of DEP bands evaluated in the experiments ranged from 81 to 139.

A study on the effect of deoxynivalenol on serotonin receptor binding in pig brain membranes.

Central serotoninergic (5-hydroxytryptamine, 5HT) pathways are believed to be involved in the mechanisms of anorexia and/or emesis evoked by the trichothecene mycotoxin deoxynivalenol (DON). Using an in vitro membrane receptor binding assay, the competitive potency of DON was investigated against several radioactive ligands that have a high affinity for selective 5HT receptor subgroups. Receptor site densities and displacement profiles in twelve selected regions of pig brain were investigated.

Fate and residues of 14C-chloramphenicol in laying chickens.

Studies were conducted to determine the metabolic fate of chloramphenicol (CAP) in White Leghorn using the 14C-labelled compound. In one experiment birds were administered orally via intra-crop, a single dose of 100 mg (equivalent to 66 mg kg-1 body weight) of CAP containing 14 microCi 14C-CAP, and its absorption, elimination and distribution in plasma were recorded. Orally dosed 14C-compound was rapidly absorbed, efficiently distributed in plasma and eliminated in excreta (> 70% in 5 hr).

Influence of Marek's disease virus strain AC-1 on cellular immunity in birds carrying endogenous viral genes.

The effects of Marek's disease virus (MDV) strain AC-1 on humoral and cellular immune responses were investigated in two lines of chickens segregating for the endogenous viral (ev) genes ev-6 and ev-12. All birds were vaccinated at 14 days of age against Newcastle disease virus (NDV). At 3 wk of age, 48 birds per line received an intraperitoneal injection of MDV (AC-1 isolate), and 24 were injected with saline.

Technical note: optimization of breed composition to maximize net merit of synthetic populations.

Determination of optimal breed (strain or line) composition is important when synthesizing a new population. In this study, the relative proportions of different breed contributions to a synthetic population are derived so that net merit of the resulting synthetic population is at a maximum. Net merit (aggregate genotype) is defined as a linear combination of genotypic values weighted by economic values.

Association between milk protein genetic variants and genetic values of Canadian Holstein bulls for milk yield traits.

The kappa-casein, beta-casein, and beta-lactoglobulin genotypes of 566 bulls were identified by polymerase chain reaction. The associations of these milk protein types with the daughter yield deviations of the 566 bulls for milk, fat, and protein were examined with a mixed model analysis using an animal model. The results suggest that kappa-casein and beta-casein loci had no significant effects on ETA of the bulls for milk, fat, and protein.