PubMed · 6236594
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Iu Mel'nishnov, Iu N Sychev. [Experimental urolithiasis].. https://pubmed.ncbi.nlm.nih.gov/6236594/
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OBJECTIVE: To assess the number of bacteria and presumptive antibiotic residues in milk fed to calves and to identify those bacteria and the antibiotic susceptibility of selected bacterial strains. DESIGN: Cross-sectional prospective study. SAMPLE POPULATION: 189 samples obtained from 12 local dairies. PROCEDURE: Samples of waste milk and milk-based fluids (eg, milk replacer, colostrum, bulk-tank milk) were obtained. Cumulative number of viable bacteria was determined. Bacteria were cultured aerobically, and antibiotic susceptibility testing of selected strains was performed. Presumptive antibiotic residues were detected by use of test kits. RESULTS: Geometric mean of the cumulative number of bacteria for waste milk samples was significantly higher than for other types of milk or milk-based products. Streptococcus sp (84/165 samples) and Enterobacteriaceae (83/165 samples) were the predominant bacteria identified, followed by Staphylococcus sp (68/165 samples). Escherichia coli was the gram-negative species most commonly isolated (52/165 samples; 32%); however, none were strain O157. Salmonella sp or Mycoplasma sp were not isolated. Of 189 samples, 119 (63%) were positive when tested for beta-lactams or tetracycline by use of 2 commercially available assays. In vitro, some bacteria were resistant to commonly used antibiotics. CLINICAL IMPLICATIONS: Waste milk that has not been effectively treated (eg, pasteurization) to reduce microbial load prior to use as calf feed should be used with caution, because it may contain a high number of bacteria that may be pathogenic to cattle and human beings. Antibiotic residues that would constitute violative amounts and existence of multiple antibiotic resistant bacterial strains are concerns in calf health management and dairy food safety.
The cholesterol-fed Richardson's ground squirrel (Spermophilus richardsonii) has proven to be an effective animal model in which to study factors that influence cholesterol gallstone formation and associated alterations in the gallbladder epithelium. Ground squirrels of either sex, fed a 2% cholesterol-enriched diet, exhibit cholesterol monohydrate crystal precipitation within 24 hours and macroscopically visible cholesterol stones by 3 weeks. Data on bile chemistry, biliary cholesterol precipitation, and various mucosal alterations occurring prior to, during, and after stone formation were collected using sampling intervals from 6 hours to 20 weeks on the diet. The results indicate that mucin hypersecretion appears to be more closely related to the initiation of nucleation than does either bile calcium of pH. Mucus hypersecretion begins within 18 hours of diet initiation and continues throughout the 20 week experimental period. Apical excrescences became more common and were larger in size during the early stages of cholelithiasis. Administration of aspirin during the experimental period demonstrated an inhibition of mucin synthesis and release. Gallstones were not formed in these aspirin-treated animals. A lectin-binding panel for 10 epithelial glycoprotein-related sugars indicated the mucin secreted by the gallbladder epithelium of 7 day experimental animals differed from that of controls. The most obvious difference was the abolition of WGA binding in the experimental animals, suggesting an absence of sialic acid expression in the mucin during the lithogenic process. Ultrastructural histochemistry indicated that both sulphomucin and sialomucin were present in the secretory granules and within the surface mucus layer of both experimental and control animals. Experimental animals, however, exhibited a significant predominance for sulphomucin. This pattern varies from that typically seen in other regions of the gastrointestinal tract where sialomucins predominate during pathologic processes.
Modification of methane emission from ruminants by the use of L-cysteine and/or a microbial preparation in wethers fed lucerne hay was assessed in an open circuit respiratory trial according to a 4 x 4 Latin squared design. L-Cysteine (0.1 g kg-1 W0.75, as sulphur equivalent) was drenched daily to wethers as an aqueous solution of hydrochloride. The microbial preparation was a dried mixture of Bacillus subtilis, Bacillus cereus, Bacillus thuringiensis, Pseudomonas fluorescens, Streptomyces cellulosae, Streptomyces albidoflavus and Saccharomyces lypolyticum. The microbial preparation was added at 87 mg kg-1 metabolic weight (W0.75) to the daily diet of a wether sheep offered lucerne chaffed hay at a maintenance level of 54 g DM kg-1 W0.75. L-Cysteine suppressed methane emission from the sheep by 13% whereas the microbial preparation actually increased methane emission by 18%. Oxidation-reduction potential, pH, ammonia and VFA were non-significantly influenced by the applied treatments.