Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.     

Conduct,Oversight, and Ethical Considerations of Clinical Trials in Companion Animals with Cancer: Report of a Workshop on Best Practice Recommendations

Development of effective and safe treatments for companion animals with cancer requires the collaboration of numerous animal health professionals and the full engagement of animal owners. Establishing ‘Best Practice Recommendations’ for clinical trials in veterinary oncology represents an important step toward meeting the goal of rigorous clinical trial design and conduct that is required to establish valid evidence. Likewise, optimizing patient welfare and owner education and advocacy is crucial to meet the unique ethical obligations to both owners and animals enrolled in these clinical trials and to ensure trust in the team conducting the research. To date, ‘Best Practice Recommendations’ for clinical trial conduct have not been reported for veterinary oncology. This document summarizes the consensus of a workshop held in November, 2014 to identify relevant ethical principles and to ensure responsible conduct of clinical research in companion animals with cancer. It is intended as a working document that will be updated as advances in science and ethical considerations require. To the extent possible, existing guidelines for the conduct and oversight of clinical trials in humans have been adapted for veterinary trials to avoid duplicative effort and to facilitate integration of clinical trials such that translational research with benefits for both companion animals and humans are encouraged.     

Non-specific immunity parameters and the formation of advanced glycosylation end-products (AGE) in rainbow trout, Oncorhynchus mykiss (Walbaum), fed high levels of dietary carbohydrates

The effects of long-term hyperglycaemia (5 months), through feeding high levels of dietary carbohydrates, on the non-specific immunity parameters of rainbow trout, Oncorhynchus mykiss (Walbaum), was assessed. Fish were fed one of three diets composed of a basal diet containing ≈ 14% digestible carbohydrate which was progressively diluted with gelatinized potato starch in the following ratios of basal diet to supplemental carbohydrate (gelatinized potato starch): 65:00, 65:20, 65:35. The three diets were pair-fed based on the feed intake of the fish fed the diet containing the highest level of starch (65:35) and representing 100% intake. The other diets were then fed at different levels in a manner that allowed all the groups of fish in the same block to receive the same amount of the basal diet [e.g. the basal diet (undiluted, 65:00) was fed at 65% of the dietary intake of the 65:35 diet]. Blood glucose concentrations and relative liver-to-body size increased with increased dietary carbohydrate intake. Feeding supplemental carbohydrates resulted in a small increase in weight gain of the fish at both supplemental levels. Pronephros tissue lysozyme activity and pronephros macrophage superoxide production were not affected by the dietary treatments. The results suggest the presence of advanced glycosylation end-products in muscle tissue collagen, but were not significantly different between treatments. No substantial effect of long-term feeding of a high carbohydrate diet on the non-specific immunity of rainbow trout was observed. However, the results suggest that dietary carbohydrates may have a slight stimulatory effect on phagocytosis at low–moderate levels.     

6-hydroxylation: effect on the psychotropic potency of tryptamines

6-Hydroxy-5-methoxy-N,N dimethyltryptamine and 5-methoxy-N, N-dimnethyltryptamine were synthesized and their psychotropic effects compared on trained rats in a Skinner box. The nonhydroxylated form was the more po tent. The metabolism of 5-methoxytryp tophol acetate ester was also studied to determine whether hydroxylation might occur in other than the six position with exogenous indoles. One metabolite was formed, with properties of a hydroxy-5-methoxyindole-3-acetic acid, which proved on chromatography not to be the 6-hydroxy structural isomer. Phar macologic and metabolic studies suggest that psychotropic activity of trypt amines may result from metabolites other than the 6-hydroxylated forms.     

Clinical validation of a proANP 31-67 fragment ELISA in the diagnosis of heart failure in the dog

Atrial natriuretic peptide (ANP) is a polypeptide hormone found in increased concentrations in the plasma of dogs with heart failure. However, problems arise in using ANP as a diagnostic marker for heart failure because of its short half-life in plasma, proteolysis post-collection and the necessity for a radioimmunoassay. The diagnostic utility of a proANP 31-67 ELISA for the detection of heart failure in dogs was evaluated using plasma collected from 31 dogs with clinical and radiographic signs of heart failure and control samples from 40 dogs considered to be free of cardiac disease. Log proANP 31-67 levels were significantly higher in the heart failure group (P < 0.001). In this population of dogs, using a cut-off value of 1,750 fmol/ml, the sensitivity and specificity of the assay were 83.9 per cent and 97.5 per cent, respectively. Using a cut-off of 1,350 fmol/ml, the sensitivity and specificity were 93.5 per cent and 72.5 per cent, respectively. It is concluded that a proANP 31-67 fragment ELISA should prove to be a useful diagnostic aid in naturally occurring canine heart failure.