Chemical composition, protein quality, palatability, and digestibility of alternative protein sources for dogs

The chemical composition and protein quality of 11 alternative protein sources (chicken products, blood products, enzyme-hydrolyzed fish protein concentrate, soybean meal, and spray-dried pork liver) were determined, and an experiment was conducted to determine palatability and digestibility of processed red blood cell-containing diets. Chicken protein sources differed in concentrations of CP, acid-hydrolyzed fat, and total AA (TAA) by 20, 31, and 24%, respectively, and GE by 1.7 kcal/g. Blood protein sources varied little in acid-hydrolyzed fat and GE concentrations, but concentrations of CP and TAA differed by 11 and 8%, respectively. Protein solubility of chicken and blood protein source categories averaged 57 and 69%, respectively. Protein solubility of enzyme-hydrolyzed fish protein concentrate, soybean meal, and spray-dried pork liver was 53, 67, and 26%, respectively. Based on calculations from immobilized digestive enzyme assay values, lysine digestibility averaged approximately 80.4 and 81.7% for blood and chicken protein sources, respectively. Lysine digestibility values for soybean meal and spray-dried pork liver were 89 and 77%, respectively. A chick protein efficiency ratio (PER) assay showed that chicken protein sources had high protein quality values, as the PER ranged from 2.7 to 5.3, whereas blood protein sources had poor protein quality (PER values less than 1.5). Enzyme-hydrolyzed fish protein concentrate, spray-dried pork liver, and soybean meal had high protein quality (PER values greater than 2.8). In the dog palatability and digestibility experiments, a corn and chicken-based diet supplemented with either 0 or 3% processed red blood cells was tested. The palatability test showed that dogs consumed more of the diet that contained 0% vs. 3% processed red blood cells. The intake ratio for the 3% processed red blood cells diet was 0.34. Nutrient digestibilities did not differ, except for CP, where the digestibility was greater (P = 0.01) for dogs consuming the 0% processed red blood cells diet. These data suggest that chemical composition and quality of alternative protein sources differ greatly among ingredients within the same category. Palatability data suggest that a processed red blood cells-containing diet is not highly palatable but, when this diet was offered as only one food, dogs demonstrated no aversion response but some decrease in protein digestion.     

In vitro generation of mature neutrophils from canine Lin- bone marrow cells

The major goal of this work was to describe the in vitro generation of mature functional neutrophils derived from a canine enriched haematopoietic progenitor cell population. We have utilised lineage depletion by immunomagnetic selection to isolate a canine haematopoietic progenitor cell population. The physical, immunological, metabolical and morphological methodologies employed in this study have permitted us to isolate and define a cell population enriched in Rh-123low and CD34+ cells. Irradiated pre-established long-term bone marrow cultures (LTBMC) were utilised to determine the self-renewal ability of lineage negative (Lin-) cells, as well as their capacity to differentiate into mature functional neutrophils. The authors demonstrate for the first time that canine neutrophils derived from Lin- cells are able to produce oxyradicals, express a specific neutrophil surface antigen, and contain gelatinase granules. These characteristics enable them to migrate through basement membranes to act as a first line defence mechanism. The fact that these cells are able to differentiate into functional mature cells, and give rise to long-term culture-initiating cells (LTC-IC) after 35 days of culture, allows the authors to assure that the isolated canine enriched haematopoietic cell population exhibit functional characteristics, associated with primitive haematopoietic cells.     

Quantitation of house dust mite allergens (Der f 1 and group 2) on the skin and hair of dogs

OBJECTIVE: To determine the concentration of house dust mite (HDM) allergens, Der f 1 and group 2, on the skin and hair of dogs and whether associations exist between the presence of Der f 1 and group 2 allergens on the skin and hair of dogs and household and dog characteristics. ANIMALS: 63 pet dogs from 50 homes. PROCEDURE: Dogs were weighed and body surface area in square meters was determined. Skin and hair samples were obtained by vacuuming dogs. Collected dust was analyzed by use of standard ELISA techniques. RESULTS: HDM allergen was detected in 21 of 59 skin and hair samples. Presence of group 2 allergen on skin and hair of dogs was significantly associated with long hair, compared with short or medium length hair. Median house dust sample concentrations of Der f 1 and group 2 allergens were high in homes with dogs that had skin and hair samples that were positive for Der f 1 and group 2 allergens. Dogs with skin and hair samples that were positive for Der f 1 and group 2 allergens resided in homes with a high number of house dust samples that were positive for Der f 1, group 2, or both allergens and in homes with a mean house dust sample allergen concentration of > or =2 microg/g of dust. CONCLUSIONS AND CLINICAL RELEVANCE: Associations exist between environmental HDM allergen concentrations and HDM allergens on the skin and hair samples of dogs. Environmental allergen load is a major factor in accumulation of allergens on the skin and hair of dogs.     

第9次国际食品中兽药残留立法委员会会议

第９次国际食品中兽药残留立法委员会会议国际食品中兽药残留立法委员会（ＣｏｄｅｘＣｏｍｍｉｔｔｅｅｏｎＲｅｓｉｄｕｅｓｏｆＶｅｔｅｒｌｎａｒｙＤｒｕｇｓｉｎＦｏｏｄｓ，简称ＣＣＲＶＤＦ）第９次全体会议于１９９５年１２月５—８日在美国首府华盛顿举行。来自...     

Multiple antimicrobial resistance region of a putative virulence plasmid from an Escherichia coli isolate incriminated in avian colibacillosis

Infections due to Escherichia coli have been costly to the poultry industry, but the exact virulence mechanisms used by these organisms to cause disease in birds remain undefined. Several factors have been shown to contribute to the virulence of avian E. coli, and many of the genes encoding these factors have been found on large conjugative plasmids. Because of the occurrence of antimicrobial resistance genes on these same plasmids, it is possible that the use of antimicrobial agents may select for persistence of E. coli containing such plasmids. In the present study, a subclone of one of these plasmids was identified as likely containing some virulence and antimicrobial resistance genes. In an effort to better understand the relationship between virulence and resistance in these plasmids, this subclone was sequenced and the sequence analyzed. Analysis of this 30-kilobase (kb) region of plasmid pTJ100 revealed a mosaic of virulence genes, insertion sequences, antimicrobial resistance cassettes, and their remnants. Many of the resistance genes found in this region were expressed under laboratory conditions, indicating that certain antimicrobial agents, including disinfectants, antibiotics, and heavy metals, could promote selection of E. coli containing such plasmids in the production environment. Also, analysis of the G + C content of this clone indicated that it is the likely consequence of a complex evolution with components derived from various sources. The occurrence of many mobile elements in conjunction with antimicrobial resistance and virulence genes in this 30-kb region may indicate that the genetic constitution of the clone is quite plastic. Although further study will be required to better define this plasmid's role in avian E. coli virulence, the sequence described here is, to our knowledge, the longest known contiguous sequence of a ColV plasmid yet presented. Analysis of this sequence indicates that this clone and its parent plasmid may be important to the pathogenesis of avian colibacillosis and the evolution of avian E. coli virulence.     

Preference of Sheep for Three Forms of Mucuna Forage and the Effect of Supplementation with Mucuna Forage on the Performance of Sheep

Assessment of the preference of sheep for fresh, dried or ensiled forms of mucuna (Mucuna pruriens var utilis) forage was followed by investigations into the effect of supplementing straw-based diets with the forage. Four sheep were offered fresh, dried and ensiled forms of the forage in a cafeteria style to assess their preference. In the second experiment, 20 sheep were randomly assigned to four dietary treatments, namely, alkali-treated straw only (M0), treated straw supplemented with mucuna forage at 0.3% (M10), 0.6% (M20) or 0.75% (M25) of body weight (approximately 10%, 20% and 25%, respectively, of the total dry matter intake). The daily feed intakes were determined and the sheep were weighed weekly for 10 weeks. The sheep showed a marked preference for fresh mucuna forage over either the dried or ensiled forms. The total dry matter intake increased by 15% and 21%, respectively, with M20 and M25. All the groups lost weight over the feeding period. However, only M0 gave weight losses during the second half of the feeding period. The feed conversion efficiency followed a trend similar to that for weight gains. M20 had the greatest effect on growth and feed conversion efficiency.     

Ear cleaning: the UK and US perspective

Ear cleaning helps maintain the normal otic environment and is important in the treatment of otitis. Over cleaning, however, may trigger otitis through maceration of the epidermal lining. Simple manual cleaning is useful for routine cleansing but doesn't remove tightly adherent debris. Bulb syringes are more vigorous but may damage the ear in inexperienced hands. Devices using mains water pressure or dental machines are also available. Thorough cleaning of the ear canals and middle ear cavity can only be achieved by retrograde flushing using specially adapted catheters, feeding tubes or video otoscopes under anaesthesia. Myringotomy, inspection and cleaning of the middle should be performed if the tympanic membrane appears abnormal. There are a wide variety of cleaning fluids available. Ceruminolytics soften and dissolve cerumen to facilitate cleaning. Surfactants emulsify debris, breaking it up and keeping it in solution. Astringents dry the ear canal surface, preventing maceration. Maintaining a low pH and incorporating antimicrobial agents can inhibit microbial proliferation and glucocorticoids can be used to reduce inflammation. Adverse effects and contraindications following ear cleaning can include maceration, contact reactions, otitis media, ear canal avulsion, vestibular syndrome, Horner's syndrome, facial nerve paralysis and deafness. Care should be exercised in selecting cleaning fluids if the tympanic membranes are ruptured.     

Immune response to recombinant Escherichia coli Iss protein in poultry

Colibacillosis accounts for significant losses to the poultry industry, and control efforts are hampered by limited understanding of the mechanisms used by avian pathogenic Escherichia coli (APEC) to cause disease. We have found that the presence of the increased serum survival gene (iss) is strongly associated with APEC but not with commensal E. coli, making iss, and the protein it encodes (Iss), candidate targets of colibacillosis control procedures. To assess the potential of Iss to elicit a protective response in chickens against APEC challenge, Iss fusion proteins were produced and administered subcutaneously to four groups of 2-wk-old specific-pathogen-free leghorn chickens. At 4 wk postimmunization, birds were challenged with APEC from serogroups 02 and 078 via intramuscular injection. At 2 wk postchallenge, birds were necropsied, and lesions consistent with colibacillosis were scored. Also, sera were collected from the birds pre- and postimmunization, and antibody titers to Iss were determined. Immunized birds produced a humoral response to Iss, and they had significantly lower lesion scores than the unimmunized control birds following challenge with both APEC strains. Birds that received the smallest amount of immunogen had the lowest lesion scores. Although further study will be needed to confirm the value of Iss as an immunoprotective antigen, these preliminary data suggest that Iss may have the potential to elicit significant protection in birds against heterologous E. coli challenge.