Effects of supplementation on voluntary forage intake, diet digestibility, and animal performance

A data base was constructed to describe and estimate supplementation effects in nonlactating cattle consuming forage ad libitum. The data base included 66 publications on 126 forages (73 harvested and 53 grazed) and a total of 444 comparisons between a control, unsupplemented treatment and a supplemented treatment. Daily gains were reported for 301 comparisons and voluntary intake for 258. Direct measures of forage digestibility were reported for 202 comparisons, and total diet digestibility for 150. Supplements did not increase gain in all cases. Change in ADG due to supplement was not related closely to intake of supplemental TDN. Lowest increases in ADG were with native forages supplemented with molasses alone or with low intakes of molasses containing high levels of NPN. Greatest increases in gain were with improved forages, supplements with > 60% TDN, and supplemental CP intake > .05% of BW. Supplements decreased voluntary forage intake (VFI) when supplemental TDN intake was > .7% of BW, forage TDN:CP ratio was < 7 (adequate N), or VFI when fed alone was > 1.75% of BW. When supplements increased VFI, forage TDN: CP ratio was > 7 (N deficit), and VFI when fed alone was often low. There was little relationship between change in VFI and sources of supplemental CP and TDN. Supplements caused total diet TDN concentration to deviate from expected values by -10 to +5% of OM. When supplemental TDN intake was > .7% of BW, diet TDN concentration was always less than expected. There was little relationship between deviation from expected total diet TDN and type or composition of forages or supplements. Empirical multiple regression equations were developed to estimate effects of supplements on VFI and total diet TDN concentration. The most acceptable intake equation estimated VFI when fed with supplement (r2 = .84) That equation included VFI when fed alone, supplement intake, CP and TDN concentrations in forage and supplement, and classification codes describing forages and supplemental energy. The most acceptable equation for estimating total diet TDN concentration included only the expected total diet TDN concentration (r2 = .87). These equations may be used in nutritional models to account for associative effects.

Compliance matching stent placement in the carotid artery of the swine promotes optimal blood flow and attenuates restenosis

OBJECTIVES

We assessed the value of a gradient-compliant stent in an animal model.

METHODS

Bilateral carotid arteries were stented with nitinol stents having variable-oversizing, variable-stiffness, and with (CMS, 10 animals) and without (SMART, four animals) compliance-matching endings. Angiography, hemodynamic, scanning-electron-microscopic and histological analyses were performed at 3-month. The protocol was completed in 14 among 19 swines.

RESULTS

Transient (1-month) exaggerated recoil, attributable to stress-induced phasic inhibition of vasorelaxation, developed at CMS endings. At mid-term, all stents were endothelialized; CMS-stents, but not SMART-stents, were incorporated into walls (one-strut-thickness). Restenosis developed outside SMART-stents (cell migration+wall-compensatory enlargement) whereas CMS-stents elicited no or focalized cell-accumulations at endings that bulged vascular walls radially outward. SMART-stents were blood-flow neutral, whereas CMS-stents favored (higher-stiffness, higher-oversizing) or opposed (lower-stiffness, less-oversizing) carotid blood flow.

CONCLUSIONS

Direct carotid stenting with stents having compliance-matched endings and specific requirements of stiffness and oversizing can optimize blood flow to the brain and restrict local restenosis.

Occurrence of Campylobacter in retail foods in Ireland

A surveillance study was carried out to determine the prevalence of Campylobacter in a range of retail foods purchased in three Irish cities over a 20-month period between March 2001 and October 2002. In total 2391 food samples were analysed during this period. Campylobacter was isolated from 444 raw chicken (49.9%), 33 turkey (37.5%) and 11 duck samples (45.8%). Lower isolation rates of 7/221 (3.2%), 10/197 (5.1%) and 31/262 (11.8%) were observed for raw beef, pork and lamb, respectively. One sample of pork paté from 120 samples analysed (0.8%) was Campylobacter-positive. A total of three shellfish samples (oysters) from 129 raw specimens examined (2.3%) were found to contain Campylobacter. Low prevalences of the organism (0.9%) were also isolated from fresh mushrooms. Of 62 raw bulk tank milk samples analysed, Campylobacter was recovered in a single sample (1.6%). Campylobacter was not detected in any of the comminuted pork puddings, prepared vegetables and salads, retail sandwiches or cheeses made from unpasteurised milk. In total, 543 Campylobacter were isolated from all of the food samples analysed, of which 453 (83.4%) were confirmed as Campylobacter jejuni and the remaining 90 (16.6%) as Campylobacter coli.

Strong-weak coupling self-duality in the two-dimensional quantum phase transition of p + ip superconducting arrays

The 2D quantum phase transition that occurs in a square lattice of Josephson-coupled p +/- ip superconductors is an example of how four-body interactions in d = 2 reproduce nonperturbative effects caused by two-body interactions in d = 1. The ordered phase has an unconventional "bond order" of the local T-breaking variable. This problem can be analyzed using an exact self-duality; this duality in classical notation is the 3D generalization of the Kramers-Wannier duality of the 2D Ising model, and there are similar exact dualities in dimensions d > or = 3. We discuss the excitation spectrum and experimental signatures of the ordered and disordered phases, and the relationship between our model and previously studied behavior of 2D boson models with four-boson interactions.

Clinical outcome of Burkholderia cepacia complex infection in cystic fibrosis adults

BACKGROUND

The Burkholderia cepacia complex (BCC) is one of the most important groups of organisms infecting cystic fibrosis (CF) patients. The aim of the study was to examine how infection with BCC affects clinical outcome.

METHODS

Nineteen CF adults infected with BCC and 19 controls infected with Pseudomonas aeruginosa were studied over a 4-year period. The best forced expiratory volume in 1 s (FEV(1)) and body mass index (BMI) for each year were recorded and annual rate of decline calculated.

RESULTS

The BCC infected group displayed a significantly greater reduction of FEV(1) and BMI compared to the P. aeruginosa infected group (p=0.001 and p=0.009, respectively). Sixteen patients infected with a single Burkholderia cenocepacia strain had a significantly greater rate of FEV(1) decline compared to those infected with Burkholderia multivorans (n=3) or P. aeruginosa (p=0.01 and p<0.0001, respectively). The rate of BMI decline was significantly greater in patients infected with B. cenocepacia compared to those with P. aeruginosa (p=0.007), but not significantly different in those with B. multivorans (p=0.29).

CONCLUSION

BCC infection is associated with an accelerated decline in pulmonary function and BMI. Infection with a single B. cenocepacia strain was associated with a more rapid decline in lung function than those infected with either B. multivorans or P. aeruginosa.

Nucleotide sequence analysis of the recA gene and discrimination of the three isolates of urease-positive thermophilic Campylobacter (UPTC) isolated from seagulls (Larus spp.) in Northern Ireland

Nucleotide sequencing after TA cloning of the amplicon of the almost-full length recA gene from three strains of UPTC (A1, A2, and A3) isolated from seagulls in Northern Ireland, the phenotypical and genotypical characteristics of which have been demonstrated to be indistinguishable, clarified nucleotide differences at three nucleotide positions among the three strains. In conclusion, the nucleotide sequences of the recA gene were found to discriminate among the three strains of UPTC, A1, A2, and A3, which are indistinguishable phenotypically and genotypically. Thus, the present study strongly suggests that nucleotide sequence data of the amplicon of a suitable gene or region could aid in discriminating among isolates of the UPTC group, which are indistinguishable phenotypically and genotypically.

Current trends in the molecular diagnosis of infective endocarditis

The introduction of molecular methods into biomedical science, particularly nucleic acid amplification techniques including the polymerase chain reaction, has significantly improved the diagnosis of several diseases. Likewise, the adoption of such molecular techniques to aid in the detection and identification of causal organisms in patients with infective endocarditis (IE) has been particularly beneficial in cases of difficult, atypical or culture-negative IE. Several different molecular approaches have been suggested for the diagnosis of IE, including variations in the type of cardiological specimens examined, nucleic acid extraction, gene target and molecular platform, each presenting their own advantages and disadvantages. This review examines the molecular approach to the detection and identification of causal agents of IE and provides details and a discussion of the application of such methods, particularly those implemented over the last 7 years.

Endoscopic visualisation to aid deep anterior lamellar keratoplasty

AIMS

The aim of this study was to assess the value of endoscopy during deep anterior lamellar keratoplasty (DALK) by visualising the posterior cornea. This allows the surgeon to determine whether air injection had succeeded in stripping Descemet's membrane and endothelium from the posterior corneal stroma.

METHODS

Four whole globes for research were obtained from the Florida eye bank with consent. A 2 mm incision was placed at the limbus and the endoscope was introduced through this into the anterior chamber. A 26-gauge needle was introduced into the cornea with the bevel positioned as deep as possible and air injected into the corneal stroma. Air was injected until the whole cornea became opaque and repeated air injections were made even after an opaque cornea was noted. The endoscopic camera was used to visualise the posterior corneal surface during this procedure.

RESULTS

The view of the posterior corneal surface was clear and introduction of the probe did not interfere with the air dissection. In all four eyes, despite ease of air injection and diffuse corneal air infiltration, no large air bubble dissection of Descemet's membrane from adjacent stroma occurred. Instead multiple blistering of the posterior corneal surface could be seen.

CONCLUSIONS

Endoscopy provides an effective tool to visualise the posterior corneal surface during DALK, using air dissection. This technique may become a standard adjunctive procedure during DALK.

Detection of mycobacterial DNA from sputum of patients with cystic fibrosis

BACKGROUND

Patients with cystic fibrosis (CF) are at high risk from atypical mycobacterial infections. There have been few attempts to delineate the intensity of mycobacterial infection in CF patients in Ireland.

AIMS

To examine the incidence of mycobacterial DNA in an archived collection of genomic DNA extracted from the sputa of CF patients within the Northern Ireland population.

METHODS

One hundred and eighty-two CF patients (66 adults and 116 children) were examined for the presence of mycobacterial DNA in their sputum by a genus specific PCR assay based on 16S rRNA, followed by direct automated sequencing of the PCR amplicons.

RESULTS

One of 116 (0.9%) children and 2 of 66 adults were positive. Sequence identity revealed Mycobacterium xenopi in the paediatric patient and M. xenopi and M. chelonei in the two adult patients. False-positive results occurred in 11 patients (four adults), mainly due to Corynebacterium spp.

CONCLUSIONS

There was a low prevalence of Mycobacterium spp in the CF patient population. All PCR positive results should be confirmed by direct automated sequencing and an alternative specific assay employed. Enhanced molecular screening will contribute in understanding their role as opportunistic pathogens in patients with worsening lung function.

Haemophilus segnis: a rare cause of endocarditis

This report presents a case of endocarditis due to Haemophilus segnis, which represents a speciation difficulty for the routine laboratory. In this study, a molecular approach provided speciation, which was confirmed phenotypically by a reference laboratory. The use of molecular genotypic analysis is an additional strategy in the investigation of endocarditis. It has applications not only in isolate identification but also in primary detection of infection, particularly in patients whose blood is culture negative by conventional methodologies.

Identification of novel eubacteria from spent mushroom compost (SMC) waste by DNA sequence typing: ecological considerations of disposal on agricultural land

A small study was undertaken to examine the microbiological characteristics of spent mushroom compost (SMC), which is the major waste by-product of the mushroom industry and which is regularly disposed off by application to agricultural land. The primary aim of this study was to examine SMC for the presence of faecal bacterial pathogens, including Campylobacter spp., Salmonella spp. and Listeria monocytogenes. Secondly it was desirable to quantify bacterial and fungal populations within SMC, and also qualitatively identify the diversity of bacterial populations within SMC, through employment of rDNA PCR and direct sequencing techniques on the culturable microflora. Conventional microbiological analyses of SMC material (n=30) from six commercial operations in both Northern Ireland and the Republic of Ireland, failed to detect Salmonella spp, Listeria spp. or Campylobacter spp. in any of the SMC material examined. Total aerobic plate counts gave a mean count of log10 7.01 colony forming units (cfu) per gram SMC material (range: log10 6.53-7.52 cfu/g). Fungal counts gave a mean count of log(10) 4.57 cfu per gram SMC material (range: log10 3.93-4.98 cfu/g). From a total of greater than 50 colony picks, a total of 12 bacterial morphotypes were identified and were further examined by employment of partial 16S rRNA gene amplification and sequencing techniques, yielding several genera and species, including Bacillus licheniformis, Bacillus subtilis, Klebsiella/Enterobacter sp. Microbacterium sp. Paenibacillus lentimorbus, Pseudomonas mevalonii, Sphingobacterium multivorum and Stenotrophomonas sp. This is the first preliminary report on the microbial diversity of SMC waste and demonstrates the presence of several species that have not been previously described in SMC, in addition to two potentially novel species within the genera Microbacterium and Stenotrophomonas. It is thereby important to examine the ecological microbe-microbe and plant-microbe interactions that are occurring between the native bacterial soil flora and those added annually (theoretically estimated at approximately 10(18) cells) through the application of SMC. Such studies would be beneficial in helping to ascertain the ecological consequences involved in the disposal of SMC waste on agricultural land.

Structural analysis and genetic variation of the 16S-23S rDNA internal spacer region from Micrococcus luteus strains

AIMS

To clone and sequence the 16S-23S ribosomal DNA (rDNA) internal spacer region (ISR) from Micrococcus luteus.

METHODS AND RESULTS

The primer pair for 16S-23S rDNA ISR amplified a fragment of about 850 bp in length for two strains, JCM3347 and JCM3348 and a fragment of about 790 bp for a strain, ATCC9341. After sequencing the ISRs were identified by the comparison of the ISRs and the flanking regions of ISR.

CONCLUSIONS

Although the sequence difference of the ISR occurred at only one position between the two JCM strains, the highly variable length (440 and 370 bp) and sequence similarity (about 40%) were demonstrated between the ISRs of the two JCM strains and a ATCC strain.

SIGNIFICANCE AND IMPACT OF THE STUDY

A CCTCCT sequence was first detected at the 3'-end of the 16S rDNA of the three strains. Moreover, highly similar sequence to the 21-bp region containing a putative rRNA processing site was observed in the ISR of the three strains. Interestingly, no intercistronic tRNAs were demonstrated in the ISRs from the three strains.

Purulent rhinitis and otitis caused by Pseudomonas aeruginosa in sheep showered with contaminated 'shower wash'

Three crossbred lowland ewes developed a severe purulent rhinitis and another three ewes developed a severe purulent otitis externa/media after being showered with a wash that had been used 24 to 48 hours before on a separate group of Cheviot ewes with lesions of dermatitis. Pseudomonas aeruginosa was isolated in pure growth from the aural and nasal abscesses and also from the dermatitis lesions. Extended antibiotic susceptibility testing and the random amplification of polymorphic DNA indicated that a single clonal type was associated with the rhinitis and otitis and with the dermatitis, providing strong evidence of an epidemiological link between the lesions of dermatitis and the aural and nasal abscesses through the use of the contaminated 'shower wash'.

Novel employment of lactate dehydrogenase release from porcine aortic endothelial cells (PAEC) as a quantitative marker of cytotoxic activity in thermophilic Campylobacter spp. from human faecal isolates, poultry and environmental sources

The aim of this study was to employ a novel cytotoxicity assay based on primary porcine aortic endothelial cells in combination with a lactate dehydrogenase release assay to quantitatively determine differences in cytotoxin production between Campylobacter jejuni, C. coli, C. lari and urease-positive thermophilic campylobacters (UPTC), isolated from human faeces, animals and environmental sources. Campylobacter isolates totalling 34 and comprising of C. jejuni (n = 24) C. coli (n = 5) and UPTC (n = 4) and C. lari (n = 1) were analysed. The cytotoxic response ranged from 32.15 to 64.47% and 33.08 to 59.41%, for C. jejuni from chicken and human isolates, respectively and there was no statistically significant difference (P > 0.05) in cytotoxic response between C. jejuni isolated from humans and chicken isolates (50.78% versus 50.55% cytotoxicity, respectively). However, there was a difference in response between C. jejuni and C. coli isolated from chickens (50.78% versus 33.22% cytotoxicity, respectively). The greatest cytotoxic response was obtained with the UPTC group of organisms examined (n = 4 isolates) (mean cytotoxic response = 57.11% cytotoxicity. Employment of this cytotoxin assay may help identify virulent strains in poultry that could potentially proceed to cause clinical problems for humans and thus intervention measures targeted at the reduction or elimination of such specific strains, may be sought.

Mycobacterium celatum pulmonary infection

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Development of a Gram-negative selective agar (GNSA) for the detection of Gram-negative microflora in sputa in patients with cystic fibrosis

AIMS

To develop a selective agar medium to help detect and quantify Gram-negative flora in the sputum of patients with cystic fibrosis (CF).

METHODS AND RESULTS

A novel Gram-negative Selective Agar (GNSA) medium was developed consisting of tryptone soya broth (30 g), bacteriological agar no.1 (10 g), yeast extract (5 g), crystal violet (2 mg), nisin (48 mg), novobiocin (5 mg), cycloheximide (100 mg), amphotericin (2 mg) and double distilled water (1 l), for the selective culture of all Gram-negative flora from the sputum of patients with CF. GNSA was able to support the proliferation of all 34 Gram-negative organisms examined, including 23 species most commonly associated with CF, but was unable to support the growth of the 12 Gram-positive or seven fungal organisms examined. Sensitivity studies demonstrated that the GNSA medium was able to detect not less than 1.50 x 102 CFU ml-1 sputum Pseudomonas aeruginosa, 2.38 x 102 CFU ml-1 sputum Burkholderia cepacia genomovar IIIb and 6.70 x 103 CFU ml-1 sputum Stenotrophomonas maltophilia. A comparison of the microbial flora detected in the sputa of 12 adult CF patients by employment of routine bacteriological agar media and GNSA, demonstrated that GNSA was able to detect all Gram-negative organisms cultured by routine media, but had the advantage of detecting Alcaligenes xylosoxidans in two CF patients, whom had no previous history of Gram-negative infection.

CONCLUSIONS

GNSA was unable to support the proliferation of any Gram-positive organism or yeast/fungi, but was successful in supporting the growth of all Gram-negative organisms challenged.

SIGNIFICANCE AND IMPACT OF THE STUDY

Employment of this medium coupled with semi-automated technology may aid in helping to efficiently determine Gram-negative loading of respiratory secretions, particularly in response to antibiotic intervention.

Studies on the genomic heterogeneity of Micrococcus luteus strains by macro-restriction analysis using pulsed-field gel electrophoresis

Macro-restriction analysis by means of double digestion using DraI and VspI demonstrated that they cleaved the genomic DNAs from Micrococcus luteus JCM1464(T), JCM3347, and JCM3348 into four to five fragments in a distinguishable manner by pulsed-field gel electrophoresis (PFGE). Separate digestion with DraI and VspI cleaved the genomic DNA from M. luteus ATCC9341 into a relatively limited number of restriction fragments (six pieces). SspI and XbaI cleaved the genomic DNA from each of the four strains into restriction fragments in a distinctly different and distinguishable manner.Thus, PFGE profiles after digestion with these four restriction enzymes that recognize six specific base sequences demonstrated the heterogeneity at the whole genomic DNA level among the four strains of M. luteus. The size of the genomic DNA of M. luteus ATCC9341 was estimated to be approximately 2.3 Mb by the summing the lengths of the restriction fragments generated by each three restriction enzymes (DraI, SspI, and VspI) and averaging the results.

Comparison of three techniques for estimating the forage intake of lactating dairy cows on pasture

Quantifying DMI is necessary for estimation of nutrient consumption by ruminants, but it is inherently difficult on grazed pastures and even more so when supplements are fed. Our objectives were to compare three methods of estimating forage DMI (inference from animal performance, evaluation from fecal output using a pulse-dose marker, and estimation from herbage disappearance methods) and to identify the most useful approach or combination of approaches for estimating pasture intake by lactating dairy cows. During three continuous 28-d periods in the winter season, Holstein cows (Bos taurus; n = 32) grazed a cool-season grass or a cool-season grass-clover mixture at two stocking rates (SR; 5 vs. 2.5 cows/ha) and were fed two rates of concentrate supplementation (CS; 1 kg of concentrate [as-fed] per 2.5 or 3.5 kg of milk produced). Animal response data used in computations for the animal performance method were obtained from the latter 14 d of each period. For the pulse-dose marker method, chromium-mordanted fiber was used. Pasture sampling to determine herbage disappearance was done weekly throughout the study. Forage DMI estimated by the animal performance method was different among periods (P < 0.001; 6.5, 6.4, and 9.6 kg/d for Periods 1, 2, and 3, respectively), between SR (P < 0.001; 8.7 [low SR] vs. 6.3 kg/d [high SR]) and between CS (P < 0.01; 8.4 [low CS] vs. 6.6 kg/d [high CS]). The period and SR effect seemed to be related to forage mass. The pulse-dose marker method generally provided greater estimates of forage DMI (as much as 11.0 kg/d more than the animal performance method) and was not correlated with the other methods. Estimates of forage DMI by the herbage disappearance method were correlated with the animal performance method. The difference between estimates from these two methods, ranging from -4.7 to 5.4 kg/d, were much lower than their difference from pulse-dose marker estimates. The results of this study suggest that, when appropriate for the research objectives, the animal performance or herbage disappearance methods may be useful and less costly alternatives to using the pulse-dose method.

Prevalence of bacterial faecal pathogens in separated and unseparated stored pig slurry

AIMS

To examine the prevalence and diversity of bacterial faecal pathogens in unseparated slurry, separated solids and liquid fractions from a commercial pig farm.

METHODS

A total of 43 stored slurry specimens originating from a fattening house over the period February-April 2002 were analysed, consisting of unseparated (n = 14) slurry, separated solids (n = 16) and separated liquid (n = 13). Specimens were examined for the presence of five bacterial pathogens including Salmonella spp., Shigella spp., Campylobacter spp., Escherichia coli O157 and Yersinia enterocolitica. Selective enrichment and plating methods were employed for detection of Salmonella spp. and Campylobacter spp. and conventional selective plating techniques for the remaining genera. Antibiogram profiles to 12 antibiotic agents were obtained for all Salmonella isolates obtained.

RESULTS

Salmonella spp. were identified in all components of the slurry specimens, whereas Campylobacter spp. was only recovered from the unseparated and separated liquid fractions. In both cases, the separated liquid fraction had the highest prevalence of pathogens and the separated solid fraction had the lowest prevalence. None of the slurry specimens examined were positive for E. coli O157:H7, Shigella spp. or Y. enterocolitica. Twenty-nine isolates of Salmonella were recovered from the slurry specimens, comprising seven serovars, of which Salmonella manhattan was the most prevalent, accounting for over half [15 of 29 (51.7%)] of all Salmonella isolates. Salmonella anatum, Salm. derby, Salm. give, Salm. heidelberg, Salm. simi and Salm. stanley serovars were also recovered. All Salmonella isolates were sensitive to ampicillin, augmentin (amoxicillin/clavulanic acid), chloramphenicol, ciprofloxacin, gentamicin, kanamycin and trimethoprim, but has variable resistance to tetracycline (100%), sulphonamides (84.6%), furazolidone (38.5%), nalidixic acid (15.4%) and streptomycin (15.4%). The majority (57.7%) of isolates displayed antibiotic resistance to at least two antibiotic agents, followed by 34.6% of isolates being resistant to three agents and the remainder (7.7%) being resistant to four antibiotics.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrated a marked reduction in the prevalence of Campylobacter and Salmonella in the solids component of separated pig slurry. The adoption of control processes such as aeration of slurry prior to its spread onto agricultural land and newer approaches to pathogen reduction should be investigated, to reduce the transmission of pathogens from pig slurry to the environment.