Dietary effects on bifidobacteria and Clostridium perfringens in the canine intestinal tract

Dietary effects on the intestinal microflora have gained increasing interest because of the evidence that a balanced micro ecology in the gut is important for health and well being. The aim of the present study was to evaluate the effect of different diets on faecal counts of bifidobacteria and Clostridium perfringens in dogs. Two extruded, dry diets, one supplemented with 3% chicory (1.5% inulin), a non-digestible oligosaccharide (NDO) and the other with 3% glucose (GLU) were compared with a protein rich diet (PR+) based on low quality animal derived protein sources (NDO 265, GLU 259, PR+ 726 g crude protein/kg dry matter; greaves meal and bovine lung as protein sources in PR+). Nine adult beagles were subjected to a consecutive cross-over trial. All dogs started with diet PR+, after which groups of four dogs (group A) received GLU and the other five dogs (group B) received NDO. After an intermediate wash-out period with diet PR+ for 3 weeks the A dogs were switched to diet NDO and B dogs to GLU. In the final period all dogs were fed with diet PR+. Faecal samples were collected during each period for dry matter and pH measurements. Faecal bifidobacteria and Cl. perfringens were quantified in fresh samples at the end of each feeding period and additionally on the first days after feed change from the dry diets to diet PR+. Diets NDO and GLU increased faecal dry matter and reduced faecal pH from 6.9 to 7.4 with the high protein diet to 5.9-6.5. The dry diets induced a firmer faecal consistency and a lower faecal pH, with no significant difference between NDO or GLU. Clostridium perfringens was found in all faecal specimens after feeding PR+ with counts of log 8.2-8.8 colony forming units (cfu)/g faeces. Both dry diets reduced the counts of Cl. perfringens significantly (log 3.3-4.0 cfu/g faeces). Switching from the dry diets to the high protein diet induced an increase of Cl. perfringens within 1 day, independent of the previous diet. In dogs fed PR+, bifidobacteria were detected in only four faecal samples and exclusively in the initial feeding period. During the remainder of the experiment the counts fell below the detection limit (log 6 cfu/g faeces). The faecal concentrations of bifidobacteria increased with both dry diets. Slightly higher concentrations (log 9.6-9.7 cfu/g faeces) were obtained from dogs fed the dry diet containing NDO compared with the diet containing glucose (log 9.3-9.4 cfu/g faeces). The increase was small which may be related to the level of total fermentable carbohydrates in both diets which alone increase remarkably the total counts of bifidobacteria. In conclusion, distinct dietary effects on the faecal counts of Cl. perfringens and bifidobacteria with a clear antagonistic pattern were observed. The main factor was the protein source and level in the diet. In this case, NDO favoured the concentrations of bifidobacteria to a limited degree. Further studies are needed to evaluate time effects, metabolic consequences and the potential implication for health promotion in pets.     

Simultaneous quantitation of equine cytokine mRNAs using a multi-probe ribonuclease protection assay

A rapid multi-probe ribonuclease protection assay (RPA) was developed to quantitate equine-specific cytokine mRNA levels in activated equine monocyte-derived macrophages (EMDM) and equine peripheral blood mononuclear cells (EPBMC). Eleven template plasmids specific to 10 equine cytokine genes and the beta-actin gene were generated from which radiolabeled anti-sense RNA probes were produced. The multi-probe RPA simultaneously quantitated mRNA levels of equine IL-1alpha, IL-1beta, IL-6, IL-8, IL-10, IL-12 p35, IL-12 p40, IFN-gamma, TGF-1beta and TNF-alpha in EPBMC and EMDM with coefficients of variation as low as 0.03-0.08 (3-8%) when normalized to beta-actin expression. This sensitive and rapid assay provides a valuable tool for studies of equine immune responses.     

Isolation of mycoplasma species from the lower respiratory tract of healthy cattle and cattle with respiratory disease in Belgium

Between 1997 and 2000, a total of 150 healthy cattle and 238 animals with respiratory disease were examined for six Mycoplasma species. Attempts were made to detect Mycoplasma canis, Mycoplasma dispar and Ureaplasma diversum in calves with recurrent disease, and all three of these species were identified in calves with recurrent disease and in healthy lungs. In healthy calves, 84 per cent of bronchoalveolar lavage fluids were mycoplasma free; when cultures were positive, Mycoplasma bovirhinis was the only species isolated. Mycoplasmas were isolated from 78 per cent of animals suffering recurrent respiratory disease and from 65 per cent of acute respiratory cases. Mycoplasma bovis was isolated from bronchoalveolar lavages from 35 per cent of calves suffering recurrent respiratory disease, and from 50 per cent of acute cases, and from 20 per cent of pneumonic cases examined postmortem. M bovis was associated with other Mycoplasma species in 44 per cent of cases. M dispar was also isolated from 45.5 per cent of calves suffering recurrent respiratory disease, often in association with M bovis. M canis was identified for the first time in diseased Belgian cattle. Other mycoplasmas, including Mycoplasma arginini, Mycoplasma alkalescens and U diversum, were isolated less frequently. Associations between mycoplasmas and other pathogens were often observed. Among lungs infected with Pasteurella and/or Mannheimia species, more than 50 per cent were mixed infections with M bovis.     

Catalase activity in equine semen

OBJECTIVE: To characterize the activity of catalase in equine semen. ANIMALS: 15 stallions of known and unknown reproductive history. PROCEDURE: Seminal plasma was collected from raw equine semen by centrifugation, and samples of seminal plasma were frozen prior to assay for catalase activity. Tissue samples (n = 3 stallions) from the bulbourethral gland, prostate gland, vesicular gland, and testis were homogenized, and cauda epididymal fluid was collected for determination of catalase activity. Catalase activity was determined as an enzyme kinetic assay by the disappearance of H2O2 as measured by ultraviolet spectrophotometry. RESULTS: Catalase activity in equine seminal plasma was 989.3 +/- 1678 U/ml (mean +/- SEM), and the specific activity of catalase in equine seminal plasma was 98.7 +/- 29.2 U/mg of protein. Specific activity of catalase in tissue homogenates was significantly higher in the prostate gland (954 +/- 270 U/mg of protein) than in the ampulla (59 +/- 5 U/mg of protein), bulbourethral gland (54 +/- 11 U/mg of protein), vesicular gland (39 +/- 3 U/mg of protein), cauda epididymal fluid (11 +/- 3 U/mg protein), or testis (54 +/- 6 U/mg of protein). CONCLUSIONS AND CLINICAL RELEVANCE: Equine seminal plasma contains a high activity of catalase that is derived primarily from prostatic secretions. Procedures such as semen cryopreservation that remove most seminal plasma from semen may reduce the ability to scavenge H2O2 and thereby increase the susceptibility of spermatozoa to oxidative stress.     

Examination of milk samples from experimentally infected heifers by an N-acetyl-β-D-glucosaminidase test and an antigen-capture elisa

Milk samples collected from normal and experimentally infected quarters of five heifers throughout their first lactation were examined by bacterial culture, milk cell count (MCC), N-acetyl-beta-D-glucosaminidase (NAGase) test and a monoclonal antibody based antigen-capture ELISA. The results were analysed according to the presence (mastitis positive) or absence (mastitis negative) of bacteria on culture, and the numbers of false negative and false positive results of the other three tests defined in relation to this. Similar numbers of false negative results were observed with the MCC (20), NAGase (18) and ELISA (13). False positive results due to the physiological factors present in early lactation were evident in the MCC, prominent in the NAGase test and absent from the ELISA. The major difference in false positive results associated with experimental infection between the three tests was the more rapid return to negative values of the ELISA following resolution of infection, compared with MCC and NAGase.     

Characterisation of an antiserum and development of an ELISA for glutathione peroxidase

Sheep red blood cells were fractionated by ion exchange and gel filtration chromatography to yield glutathione peroxidase approximately 99% pure. An antiserum against glutathione peroxidase was raised in the rabbit. The antiserum has been shown to cross-react with both bovine and human glutathione peroxidase by double diffusion.An enzyme linked immunosorbent assay has been developed for glutathione peroxidase which detected 6.15×10^–5 IU of the enzyme. The antiserum has also been shown to be effective in the detection of glutathione peroxidase immobolised on strips of nitrocellulose, subsequent to sodium dodecyl sulphate polyacrylamide gel electrophoresis, by second antibody conjugate. Avidin-biotin was also used to detect nitrocellulose immobolised enzyme. These techniques provide an alternative highly sensitive and specific means of assaying glutathione peroxidase which is not dependent on the lability of enzymatic activity nor the chemical specificity of the assay.     

Growth and metabolism in somatotropin-treated steers: II. Carcass and noncarcass tissue components and chemical composition

Carcass and noncarcass tissue compositional characteristics were determined in growing Hereford steers treated with daily subcutaneous injections (20.6 mg/d) of recombinantly derived bovine somatotropin (rBST) for 112 d. For carcass primal cuts, weights and rates of gain of bone, lean and total fat and site of fat deposition were not significantly affected by rBST treatments with the exception of a few tissues (loin total weight, flank total and lean weight and shank total weight). Lean to fat ratios, however, were greater (P less than .1) for the loin, flank, chuck and brisket. Weights and growth of individual muscles from the hindquarter were not affected by rBST administration. Weights and(or) average daily gains of the liver, kidneys, lungs and trachea and head were greater (P less than .05) in rBST-treated animals. Weights and (or) average daily gains were greater (P less than .1) in rBST-treated steers for water in the total body and carcass, for CP in the total body and noncarcass, and for ash in the total body, carcass and noncarcass. Ratios of CP to ether-extractable fat in the total body were greater (P less than .1) in rBST steers. These data indicate that rBST modified carcass lean and fat composition in cattle, but responses were modest compared to effects of somatotropin treatment of swine.     

The influence of tillage on NO and N2O fluxes under spring and winter barley

Abstract. There is a lack of information about the influence of tillage and time of sowing on N₂O and NO emission in cereal production. Both factors influence crop growth and soil conditions and thereby can affect trace gas emissions from soils. We measured fluxes of NO and N₂O in a tillage experiment where grassland on clay loam soil was converted to arable by either direct drilling or ploughing to 30 cm depth. We made measurements in spring for 20 days after fertilizer application to spring-sown and to winter-sown barley. Both were the second barley crop after grass. Direct drilling enhanced N₂O emission primarily as a result of restricted gas diffusivity causing poor aeration after rainfall. Deep ploughing enhanced NO emission, because of the large air-filled porosity in the topsoil. NO and N₂O emissions were smaller from winter sown crops than from spring sown crops.   The three rates of N fertilizer application (40, 80 or 120 kg N ha^–1) did not produce the expected linear response in either soil available N concentrations or in NO and N₂O fluxes. We attributed this to the lack of rainfall in the ten-day period after fertilizer application and therefore very slow incorporation and movement of fertilizer into and through the soil.