Cryptosporidium and Giardia in calves in Belgium

Cryptosporidiosis mainly occurs in calves younger than 1 month, and causes a mild to profuse diarrhea. In contrast, a Giardia infection is most frequently diagnosed in calves older than 1 month and clinical symptoms comprise a chronical and intermittent diarrhea, and ill thriving. Cattle are considered as a possible reservoir for zoonotic transmission. The objectives of the present thesis were to estimate the prevalence of both parasites in calves younger than 10 weeks, to evaluate common diagnostic techniques, to molecularly identify the parasite isolates, and to study treatment and control of giardiosis in calves. The prevalence of Giardia in dairy calves was 22% (95% CI: 12-34%) and in beef calves 45% (95% CI: 30-64%). The Cryptosporidium prevalence was estimated to be 37% (95% CI: 7-70%) in dairy and 12% (95% CI: 1-30%) in beef calves. Furthermore, 48% of the dairy and 64% of the beef farms had at least one Giardia positive calf, and 32% of the dairy and 24% of the beef farms had at least one Cryptosporidium positive calf. The Bayesian test evaluation indicated that some are both sensitive and specific diagnostic techniques for use in epidemiological studies, whereas others are less sensitive. The molecular identification revealed that the majority of the Cryptosporidium positive samples from dairy and beef calves was C. parvum, mainly the zoonotic subgenotype IIaA15G2R1. In the Giardia positive calf samples a high prevalence of infections with the zoonotic assemblage A was found. Furthermore, mixed assemblage A/E infections were identified using a new assemblage specific PCR, based on the triose phosphate isomerase gene. The identification of zoonotic lineages in the majority (for Cryptosporidium) or in a substantial part (for Giardia) of their parasite population indicate that dairy and beef calves are a potential zoonotic reservoir for human infections. The treatment and control of clinical giardiosis was studied in an experimental study to evaluate the efficacy of paromomycin sulphate, and in a field efficacy study to evaluate a combination of treatment with fenbendazole and environmental measures. Both paromomycin and fenbendazole significantly reduce cyst excretion, although in natural conditions environmental measures have to be applied

High-glucose feeding of gilthead seabream (Sparus aurata) larvae: effects on molecular and metabolic pathways

Nutritional programming has begun to arouse interest as a novel tool to alter specific metabolic pathways or functions in farmed animals. The aim of the present study was to explore the potential of early glucose stimuli to induce changes in nutrient metabolism of gilthead seabream. Nutritional conditioning was performed by delivering glucose-rich feed at three distinct recurrent periods of larval feeding regime: during first-feeding with rotifers (3 days after hatching, DAH) and mid-feeding with Artemia metanauplii (20DAH) and the beginning of inert diet feeding (30DAH), called the Recurrent treatment (REC). As opposed, the control treatment (CTRL) did not experience any glucose stimuli. At post-larval stage (from 50 to 60DAH), both treatments were challenged with a high-carbohydrate diet (50%). The immediate response to the early stimuli was assessed through gene expression of metabolic markers and by nutrient metabolism using [C-14] tracers. Each dietary stimulus induced metabolic changes on REC larvae, shown by altered expression of some genes, including those involved in glycolysis, and by a different pattern of glucose utilization. However, none of the molecular adaptations (except G6PDH gene) were persistent in the viscera and muscle of challenged post-larvae from REC group. In contrast, the glucose metabolism of challenged REC post-larvae revealed a shift towards a higher catabolism and lower glucose retention in tissues, compared to the CTRL group, suggesting an improvement of glucose oxidation pathways. In addition, the REC group showed a higher bio-conversion of glucose into lipids, indicating enhanced hepatic lipogenesis. The early stimuli did not affect the relative retention or use of amino acids or the growth and survival of challenged fish, up to 60DAH. In summary, although not substantiated at a molecular level, our data reveal that a recurrent high-glucose stimulus during larval stages affects the short-term modulation of pathways for glucose utilization in gilthead seabream. (C) 2015 Elsevier B.V. All rights reserved

The prevalence and molecular characterisation of Cryptosporidium spp. in small ruminants in Zambia

A

Effects of organic plant oils and role of oxidation on nutrient utilization in juvenile rainbow trout (Oncorhynchus mykiss)

The study compared the effect of four either fresh or force oxidized organic plant oils in diets for juvenile rainbow trout (Oncorhynchus mykiss) in which 47% of conventional LT fish meal protein was substituted by a mixture of 3 organic plant protein concentrates. Fish oil was completely substituted with either organic linseed oil; rape seed oil; sunflower oil or grape seed oil and evaluated based on feed intake, feed utilization, growth and digestibility. None of the plant oils affected feed intake and growth parameters. Organic plant oils had all a positive effect on lipid digestibility as compared with the fish oil based control diet, despite the very different FA profiles. The organic vegetable oils did not undergo autoxidation, as opposed to the fish oil control for which lipid digestibility was significantly negative influenced

Evaluatie van twee intensieve behandelingsschema's tegen Psoroptes ovis-schurft bij Belgisch witblauwe runderen op negen Vlaamse rundveebedrijven

Psoroptic mange, caused by Psoroptes ovis, is a problem on many Flemish farms where Belgian blue beef cattle are bred. Two intensive treatment schedules were evaluated on nine Belgian blue fauns with a-persistent mange problem. On farms 1 to 7, all animals were treated twice (with a seven-to-ten-days interval) with an injectable macrocyclic lactone (ML), while on the two remaining fauns, the initial treatment consisted of one injection with the long acting (LA) formulation of moxidectin (10%). Skin scrapings were taken after treatment, and when living mites were found on at least one animal, all animals (farms 1 to 7) or only positive animals (farms 8 and 9) were treated consecutively with an injectable ML. On all farms, the treated animals were clinically healthy and P ovis free at the end of winter, after two to nine treatment rounds (two injections with a seven to ten-days interval or one LA injection). Although mange reappeared on the first seven farms after the subsequent grazing season, the disease was less severe and easier to control