Beta2-agonists and cAMP inhibit protein degradation in isolated chick (Gallus domesticus) skeletal muscle

1. The role of beta2-agonist and of cAMP in chick skeletal muscle proteolytic pathways and protein synthesis was investigated using an in vitro preparation that maintains tissue glycogen stores and metabolic activity for several hours. 2. In extensor digitorum longus (EDL) muscle total proteolysis decreased by 15 to 20% in the presence of equimolar concentrations of epinephrine, clenbuterol, a selective hbetaagonist, or dibutyryl-cAMP. Rates of protein synthesis were not altered by clenbuterol or dibutyryl-cAMP. 3. The decrease in the rate of total protein degradation induced by 10(-5)M clenbuterol was paralleled by a 44% reduction in Ca2+-dependent proteolysis, which was prevented by 10(-5)M ICI 118.551, a selective fbeta2antagonist. 4. No change was observed in the activity of the lysosomal, ATP-dependent, and ATP-independent proteolytic systems. Ca2+-dependent proteolytic activity was also reduced by 58% in the presence of 10(-4)M dibutyryl-cAMP or isobutylmethylxanthine. 5. The data suggest that catecholamines exert an inhibitory control of Ca2+-dependent proteolysis in chick skeletal muscle, probably mediated by fbeta2adrenoceptors, with the participation of a cAMP-dependent pathway.     

Structure and Expression In planta of Botrytis cinerea Ubiquitin Genes

To identify genes of the necrotrophic pathogenic fungus Botrytis cinerea that are expressed during infection of tomato leaves, a differential screening of a genomic library with radioactively labelled cDNA was performed. This resulted in the identification of a B. cinerea gene, denominated Bcubi4, which encodes a precursor protein consisting of four identical head-to-tail repeats of a 76aa ubiquitin unit. Subsequently a gene denominated Bcubi1CEP79, encoding a single ubiquitin unit joined to a Carboxyl Extension Protein of 79 amino acids, was isolated. The expression of the two ubiquitin genes was studied during pathogenesis of B. cinerea on tomato. Bcubi1CEP79, but not Bcubi4, mRNA was transiently induced at 16h after inoculation. The increased expression of the Bcubi1CEP79 gene at this stage of pathogenesis might be required for enhanced ribosomal biogenesis.     

Meta‐analysis of the energy and protein requirements of hair sheep raised in the tropical region of Brazil

The objective of this study was to estimate, through mathematical models, energy and protein requirements for maintenance and gain of hair sheep raised in the tropical region of Brazil. To determine the equation parameters, a meta‐analysis of seven independent experiments of nutrient requirements was performed, comprising a total of 243 experimental units (animals), which were conducted under tropical conditions, using hair sheep in growing and finishing phases and endowed of the following quantitative data for each animal: body weight (BW ), empty body weight (EBW ), average daily gain (ADG ), empty body gain (EBG ), heat production (HP ), metabolizable energy intake (MEI ), retained energy (RE ), metabolizable protein intake (MPI ) and body protein content. The regression equations generated were as follows: for Net Energy for maintenance, (NE _m): ; for Net Energy for gain, (NE _g): ; for Metabolizable Protein for maintenance,(MP _m): MPI _(g/day) = 24.8470 (±7.3646) + 560.28 (±99.6582) × EBG _(kg/day); for Net Protein for gain, (NP _g): . The NE _m requirement was 0.246 MJ EBW^?0.75 day^?1. The metabolizable energy for maintenance requirement was 0.391 MJ EBW^?0.75 day^?1. Considering an ADG of 100 g, the NE _g requirement ranged from 0.496 to 1.701 MJ/day for animals with BW ranging from 10 to 40 kg respectively. The efficiencies of use of the metabolizable energy for maintenance and gain were 0.63 and 0.36 respectively. The MP _m requirement was 3.097 g EBW^?0.75 day^?1. Considering an ADG of 100 g, the NP _g requirement ranged from 12.4 to 10.5 g/day for animals with BW ranging from 10 to 40 kg respectively. The total metabolizable energy and protein requirements were lower than those reported by the NRC and AFRC systems. Thus, our results support the hypothesis that nutrient requirements of hair sheep raised in tropical regions differ from wool sheep raised in temperate regions. Therefore, the use of the equations designed in this study is recommended.     

Warm weather transport of broiler chickens in Manitoba. II. Truck management factors associated with death loss in transit to slaughter

This observational study was conducted to identify the cause of death and load level factors associated with mortality in 1 090 733 Manitoba broiler chickens transported to slaughter in spring and early summer. Death loss in transit was 0.346% and accounted for 19% of the total carcass condemnation. The death loss pattern was clearly bimodal, with a low death loss in 180 of 198 shipments. Cumulative death loss during the growing phase of production was consistently associated with increased transport mortalities in load level models and when comparing high death loss with low death loss truckloads. High ambient temperature at the time of slaughter and loading density of the truck were the major factors associated with exceptional death loss.     

Pharmacokinetic/pharmacodynamic modelling of robenacoxib in a feline tissue cage model of inflammation

Pelligand, L., King, J. N., Toutain, P. L., Elliott, J., Lees, P. Pharmacokinetic/pharmacodynamic modelling of robenacoxib in a feline tissue cage model of inflammation. J. vet. Pharmacol. Therap.  35 , 19–32. Robenacoxib is a novel nonsteroidal anti‐inflammatory drug developed for use in cats. It is a highly selective COX‐2 inhibitor. Results from previous feline studies showed that, despite a short half‐life in blood, the effect of robenacoxib persisted for 24 h in clinical studies. A tissue cage model of acute inflammation was used to determine robenacoxib’s pharmacokinetics and its ex vivo and in vivo selectivity for COX‐1 and COX‐2 using serum TxB₂ and exudate PGE₂ as surrogate markers for enzyme activity, respectively. After intravenous, subcutaneous and oral administration (2 mg/kg), the clearance of robenacoxib from blood was rapid (0.54–0.71 L·h/kg). The mean residence time (MRT) in blood was short (0.4, 1.9 and 3.3 h after intravenous, subcutaneous and oral administration, respectively), but in exudate MRT was approximately 24 h regardless of the route of administration. Robenacoxib inhibition of COX‐1 in blood was transient, occurring only at high concentrations, but inhibition of COX‐2 in exudate persisted to 24 h. The potency ratio (IC₅₀ COX‐1: IC₅₀ COX‐2) was 171:1, and slopes of the concentration–effect relationship were 1.36 and 1.12 for COX‐1 and COX‐2, respectively. These data highlight the enzymatic selectivity and inflamed tissue selectivity of robenacoxib and support the current recommendation of once‐daily administration.     

A Cross‐Sectional Study Examining Campylobacter and Other Zoonotic Enteric Pathogens in Dogs that Frequent Dog Parks in Three Cities in South‐Western Ontario and Risk Factors for Shedding of Campylobacter spp.

An estimated 6 million pet dogs live in Canadian households with the potential to transmit zoonotic pathogens to humans. Dogs have been identified as carriers of Salmonella, Giardia and Campylobacter spp., particularly Campylobacter upsaliensis, but little is known about the prevalence and risk factors for these pathogens in pet dogs that visit dog parks. This study examined the prevalence of these organisms in the faeces of dogs visiting dog parks in three cities in south‐western Ontario, as well as risk factors for shedding Campylobacter spp. and C. upsaliensis. From May to August 2009, canine faecal samples were collected at ten dog parks in the cities of Guelph and Kitchener‐Waterloo, Ontario, Canada. Owners were asked to complete a questionnaire related to pet characteristics and management factors including age, diet and activities in which the dog participates. Faecal samples were collected from 251 dogs, and 189 questionnaires were completed. Salmonella, Giardia and Campylobacter spp. were present in 1.2%, 6.4% and 43.0% of faecal samples, respectively. Of the Campylobacter spp. detected, 86.1% were C. upsaliensis, 13% were C. jejuni and 0.9% were C. coli. Statistically significant sparing factors associated with the shedding of Campylobacter spp. included the feeding of a commercial dry diet and the dog's exposure to compost. Age of dog had a quadratic effect, with young dogs and senior dogs having an increased probability of shedding Campylobacter spp. compared with adult dogs. The only statistically significant risk factor for shedding C. upsaliensis was outdoor water access including lakes and ditches, while dogs >1 year old were at a lower risk than young dogs. Understanding the pet‐related risk factors for Campylobacter spp. and C. upsaliensis shedding in dogs may help in the development of awareness and management strategies to potentially reduce the risk of transmitting this pathogen from dogs to humans.     

Isolation of Mycobacterium species from raw milk of pastoral cattle of the Southern Highlands of Tanzania

A study to determine the secretion of Mycobacterium spp. in milk from indigenous cattle was carried out in pastoral cattle reared in the Southern Highlands of Tanzania. The study was aimed at elucidating the dangers associated with milk-borne zoonoses in a society where milk is normally consumed raw. Out of 805 milk samples, 31 (3.9%) were positive for mycobacteria. There was a preponderance of atypical mycobacteria (87%) whereas only two isolates (6.5%) were confirmed as M. bovis. Atypical mycobacteria included: M. terrae (n=7), M. fortuitum (n=2), M. flavescens (n=13), M. gordonae (n=1) and M. smegmatis (n=4). Although the number of M. bovis positive samples was low, the habit of pooling milk may still pose great public health dangers to milk consumers in this part of the world. Moreover, isolation of atypical mycobacteria should also be considered to be a danger to human health in countries such as Tanzania, where the number of people with lowered immunity due to HIV infection is on the increase.     

Hiatal herniation as a complication of chronic diaphragmatic herniation

Three of four cases of chronic diaphragmatic herniation seen over a period of 12 months developed hiatal herniation within five to eight days of corrective surgery for the diaphragmatic herniation. None of the dogs had shown any prior signs referrable to hiatal herniation. The features that developed subsequent to diaphragmatic herniorrhaphy in all cases were dyspnoea, increased intra-abdominal pressure due to decreased abdominal domain and laxity of the oesophageal hiatus as judged subjectively at the time of surgery for hiatal herniation correction. These conditions may be significant underlying factors for the development of hiatal herniation not preceded by diaphragmatic herniation in the dog. Those associated factors accepted as important in humans, including reduced lower oesophageal sphincter tone and gastroesophageal reflux, may not be of similar importance in small animals.     

Effects of the juice of Fructus Hippophae (JFH) on thrombocytopenia induced by cyclophosphamide in rats

AIM:To investigate the effects of the juice of fructus hippophae(JFH) on thrombocytopenia in rats.METHODS:Forty-eight wistar rats were divided into control group, model group, Yixuesheng-Jiaonang (YSJN) group and JFH group. Rats were injected intraperitoneally with cyclophosphamide (CTX, 30 mg/kg) or saline once a day for 3 days. And then, Saline, YSJN or JFH was administered (ig) once a day for 11 days. On the second, fouth, sixth and eighth day, the thrombocyte were counted, the mean platelet volume (MPV) and PDW were examined. On the eighth day, the cAMP, cGMP in platelets and platelet aggregation function were also examined.RESULTS:JFH could shorten the time of blood coagulation, increase the count of platelet, and enhance the platelet aggregation function. The experiment also showed that the JFH could decrease cGMP content in platelet.CONCLUSION:JFH could enhance blood coagulation and quality of platelet and prevent thrombocytopenia induced by cyclophosphamide in rats.