Comparison of the biopotencies of nicotinic acid and nicotinamide for broiler chicks

1. Two experiments were conducted with 1056 1-d-old Cobb x Cobb feather-sexed broiler chicks, to determine the relative nicotinic acid biopotencies of nicotinic acid (NA) and nicotinamide (NAm). 2. Two methods were used: the slope-ratio technique and the broken-line model. 3. In experiment 1, using the slope-ratio technique, NAm was 0.82 as active as NA in promoting growth to 21 d of age. In experiment 2 NAm was 0.96 as bipotent as NA. 4. Applying the broken-line model to the body weight data at 21 d of age for both NA and NAm in experiment 1, it was found that NAm had approximately 0.82 NA activity. The same analysis applied to the data of experiment 2 indicated that the biopotency of NAm was 1.09. 5. A t-test of the slope-ratio values obtained in both experiments indicated that the average (0.89) was not significantly different from 1.0. 6. It was concluded that the relative biopotencies of NA and NAm in broiler chicks fed a maize-soyabean meal diet were similar.     

No evidence for avoidance of black rat scent by the presumably less competitive Natal multimammate mouse in a choice experiment

In Africa, indigenous multimammate mice (Mastomys natalensis) only appear to live commensally in houses when invasive black rats (Rattus rattus) are absent, yet little is known about the underlying mechanism. Avoidance through smell may cause the absence of M. natalensis from areas occupied by R. rattus, but this hypothesis has not yet been tested. We conducted a Y-maze choice experiment where 15 M. natalensis were offered a choice between corridors containing conspecific scent, R. rattus scent and a control scent. Residence time in the R. rattus corridor was greater than that in the control corridor but equal to that in the M. natalensis corridor, suggesting that multimammate mice do not actively avoid the scent of their invasive competitor.     

Investigating the Link between Particulate Exposure and Airway Inflammation in the Horse

Inhalant exposure to airborne irritants commonly encountered in horse stables is implicated in the pathogenesis of inflammatory airway disease (IAD) and recurrent airway obstruction (RAO), non‐infectious, inflammatory pulmonary disorders that impact the health and performance of horses across all equine disciplines. IAD and RAO have overlapping clinical, cytological, and functional manifestations of the pulmonary response to organic dust and noxious gases encountered in the barn environment. Study of these diseases has provided important but incomplete understanding of the effect of air quality upon the respiratory health of horses. In this review, the principles of particulate exposure assessment, including health‐related aerosol size fractions and size‐selective sampling, the factors influencing air quality in equine environments, and the effect of air quality on the equine respiratory tract are discussed. The objective of this review is to provide the reader with a summary of the most common chronic inflammatory airway diseases in the horse and the principles of air sampling that are essential to the planning, interpretation, and assessment of equine respiratory health‐related exposure studies.     

Identification of bovine viral diarrhea virus type 1 in yaks (Bos poephagus grunniens) in the Himalayan region

Since cattle are widely infected by bovine viral diarrhea virus (BVDV) in India, we searched for pestivirus infection in yaks. Of 71 pure and crossbred yaks from Himalayan region, pestivirus antigen was detected by Ag-ELISA in three animals. Pestivirus in leukocyte and cell culture isolated virus samples originating from positive yaks was also confirmed by RT-PCR using panpestivirus specific primers selected from 5'-untranslated region (5' UTR). The 5' UTR, N(pro) and E2 regions were sequenced and used for genetic typing. Phylogenetic analysis revealed that pestiviruses detected in three Himalayan yaks were similar genetically, belonging to BVDV-1. Antigenic characterisation of yak pestivirus also confirmed the typing as BVDV-1. This is the first report on the identification of BVDV type 1 in yaks.     

Adenosine A2A receptor agonists inhibit lipopolysaccharide-induced production of tumor necrosis factor-alpha by equine monocytes

Adenosine is an endogenous nucleoside that regulates many physiological processes by activating one or more adenosine receptor subtypes, namely A1, A2A, A2B and A3. The results of previous studies indicate that adenosine analogues inhibit lipopolysaccharide (LPS)-induced production of reactive oxygen species (ROS) by equine neutrophils primarily through activation of A2A receptors. Because peripheral blood monocytes produce cytokines that are responsible for many of the deleterious effects of LPS, the current study was performed to evaluate the effects of an array of novel adenosine receptor agonists on LPS-induced production of tumor necrosis factor-alpha (TNF-alpha), and to assess the selectively of these agonists for equine adenosine A2A over the A1 receptor. Radioligand binding studies performed with equine tissues expressing adenosine A1 and A2A receptor subtypes yielded a rank order of affinity for the equine A2A receptor of ATL307>ATL309 approximately ATL310 approximately ATL313>ATL202 approximately ATL361 approximately ATL376>ATL372>CGS21680>NECA. Co-incubation of equine peripheral blood monocytes with LPS and these agonists resulted in inhibition of TNF-alpha production with a rank order of potency that strongly correlated with their binding affinities for equine adenosine A2A receptors. Results of experiments performed with one of the adenosine receptor agonists (ATL313) and selective adenosine receptor antagonists confirmed that inhibition of LPS-induced production of TNF-alpha occurred via stimulation of A2A receptors. Although incubation of monocytes with IB-MECA, a compound purported to act as an adenosine A3 receptor agonist, reduced LPS-induced TNF-alpha production, this effect of IB-MECA was inhibited by the A2A selective antagonist ZM241385 but not by the A3 receptor antagonist MRS1220. These results indicate that the adenosine receptor subtype responsible for regulation of LPS-induced cytokine production by equine monocytes is the A2A receptor. To address the signal transduction mechanism responsible for the anti-inflammatory effects of ATL313 in equine monocytes, production of cAMP was compared in the presence and absence of either the adenosine A2A receptor antagonist ZM241385 or the adenosine A2B receptor antagonist MRS1706. In the absence of the antagonists, ATL313 increased production of cAMP; ZM241385 inhibited this effect of ATL313, whereas MRS1706 did not. Furthermore, incubation of monocytes with either the stable analogue of cAMP, dibutyryl cAMP, or forskolin, an activator of adenylyl cyclase, also inhibited LPS-induced production of TNF-alpha production by equine monocytes. Collectively, the results of the current study indicate that adenosine analogues inhibit LPS-induced production of TNF-alpha by equine monocytes primarily via activation of adenosine A2A receptors and do so in a cAMP-dependent manner. The results of this study indicate that stable adenosine analogues that are selective for adenosine A2A receptors may be suitable for development as anti-inflammatory drugs in horses.     

Seroepidemiology of infection with Toxoplasma gondii in waste pickers and waste workers in Durango, Mexico

Municipal waste is a potential source of infection for Toxoplasma gondii as it may contain contaminated meat with parasite tissue cysts and cat excrement with parasite oocysts. Therefore, we sought to determine the prevalence of T. gondii infection and associated characteristics in two populations exposed to municipal solid waste in Durango, Mexico. Ninety waste pickers and 83 waste workers of Durango City, Mexico were examined for T. gondii infection. They were tested for anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. In addition, socio-demographic and behavioural characteristics from each participant were obtained. Nineteen (21.1%) of the 90 waste pickers and seven (8.4%) of the 83 waste workers were positive for anti-T. gondii IgG antibodies. The difference in prevalence among the groups was statistically significant (P =0.03). Waste pickers aged 31-50 years showed a significantly higher prevalence (40.9%) than waste workers of the same age group (2.9%, P < 0.001). Anti-T. gondii IgM antibodies were found in two (2.2%) of the waste pickers but in none of the waste workers. The seroprevalence of T. gondii was significantly higher in workers of the waste transfer station (25.0%) than in drivers or helpers of waste vehicles (2.5%) (P =0.03). Multivariate analysis showed that T. gondii infection was associated with consuming food found in the garbage [adjusted odds ratio (OR) = 4.4; 95% confidence interval (CI) 1.6-11.8] and with lack of education (adjusted OR = 3.2; 95% CI 1.1-8.8). From this study, we conclude: (i) waste pickers may represent a risk group for T. gondii infection; (ii) lack of education might be a contributing factor for T. gondii infection; (iii) the higher the exposure to garbage, the higher the seroprevalence of T. gondii infection; (iv) Eating food products from the garbage may represent an important route for T. gondii infection.