Alleviation of excessive gas accumulation in the ruminant stomach by ritanserin

The relationships between forestomach motility and eructation rate were studied in sheep and cattle. Three ewes and 2 heifers were implanted with strain gauges on the reticulo-rumen and fitted with a cannula in the dorsal sac of the rumen. Studies were performed in sheep after induction of hypocalcemia by Na2EDTA infusion and cattle were studied after ruminal distension. Experiments were performed by measuring the rate and volume of eructated ruminal gases, using a technique by which the trachea is transected. The frequency of reticulo-ruminal contractions decreased 40% within 30 minutes of Na2EDTA infusion to the sheep. The volume of eructated gas (for 30-minute periods) decreased from 10.7 L to 5.5 L at the end of the 60-minute infusion period. Pretreatment with ritanserin (0.1 mg/kg, subcutaneously) not only prevented bloating during the ruminal stasis induced by hypocalcemia, but also significantly increased the eructated volume of gas. In cattle, ritanserin given at the same dose level (0.1 mg/kg, subcutaneously) significantly increased the volume of eructated gas after ruminal distension. This study supports the hypothesis that the caudal esophageal sphincter has a role in the rate of ruminal gas eructation and indicates that its relaxation may be due to a 5-hydroxytryptamine antagonist.     

Effect of Arbuscular Mycorrhizal Fungi and Phosphate-Solubilizing Bacteria Consortia Associated with Phospho-Compost on Phosphorus Solubilization and Growth of Tomato Seedlings (Solanum lycopersicum L.)

ABSTRACT

The exploitation of phosphate mines generates an important quantity of phosphate sludge that remains accumulated and not valorized. In this context, composting with organic matter and rhizospheric microorganisms offers an interesting alternative and that is more sustainable for agriculture. This work aims to investigate the synergetic effect of arbuscular mycorrhizal fungi (AMF), phosphate-solubilizing bacteria (PSB) and phospho-compost (PC), produced from phosphate-laundered sludge and organic wastes, and their combination on plant growth, phosphorus solubilization and phosphatase activities (alkaline and acid). Inoculated mycorrhizae and bacteria strains used in this study were selected from plant rhizosphere grown on phosphate-laundered sludge. Significant (p < .05) increases in plant growth was observed when inoculated with both consortia and PC (PC+ PSB+ AMF) similar to those recorded in plants amended with chemical fertilizer. Tripartite inoculated tomato had a significantly (p < .05) higher shoot height; shoot and root dry weight, root colonization and available P content, than the control. Co-inoculation with PC and AMF greatly increased alkaline phosphatase activity and the rate of mycorrhizal intensity. We conclude that PC and endophytic AMF and PSB consortia contribute to a tripartite inoculation in tomato seedlings and are coordinately involved in plant growth and phosphorus solubilization. These results open up promising prospects for using formulate phospho-compost enriched with phosphorus-solubilizing microorganisms (PSM) in crop cultivation as biofertilizers to solve problems of phosphate-laundered sludge accumulation.     

An investigation of links between metabolic rate and feed efficiency in European sea bass Dicentrarchus labrax

Feed efficiency (FE) is the amount of body weight gain for a given feed intake. Improving FE through selective breeding is key for sustainable finfish aquaculture but its evaluation at individual level is technically challenging. We therefore investigated whether individual routine metabolic rate (RMR) was a predictor of individual FE in the European sea bass Dicentrarchus labrax, a major species in European mariculture. The European sea bass has three genetically distinct populations across its geographical range, namely Atlantic (AT), West Mediterranean (WM), and East Mediterranean (EM). We compared FE and RMR of fish from these three populations at 18 or 24 °C. We held 200 fish (62 AT, 66 WM, and 72 EM) in individual aquaria and fed them from ad libitum down to fasting. FI was assessed for an ad libitum feeding rate and for a fixed restricted ration (1% of metabolic body weight·day⁻¹, with metabolic body weight = body weight^0.8). After being refed 12 wk in a common tank, individual RMR was measured over 36 h by intermittent flow respirometry. There was a significant effect of temperature whereby fish at 18 °C had greater mean FE (P < 0.05) and lower RMR (P < 0.001). There was also a significant effect of population, where AT fish had lower FE (P < 0.05) and greater RMR (P < 0.001) than WM and EM, at both temperatures. Despite these differences in temperature and population means, individual FE and RMR were not significantly correlated (P > 0.05). Therefore, although the results provide evidence of an association between metabolic rate and FE, RMR was not a predictor of individual FE, for reasons that require further investigation.     

Mycorrhizal autochthonous consortium induced defense-related mechanisms of olive trees against Verticillium dahliae

Journal of Plant Diseases and Protection - The present work aimed to investigate the effect of an autochthonous mycorrhizal consortium in enhancing olive tree tolerance against Verticillium...     

Evaluation de l'efficacité de traitements de semence vis-à-vis de Plasmopara halstedii

Le mildiou du tournesol causé par Plasmopara halstedii est une maladie économiquement importante. Les dégâts sont particulièrement redoutés lors des printemps humides. En absence de cultivars de tournesol génétiquement résistants, seul le traitement des semences avec des produits systémiques est envisageable. Cette étude a été réalisée pour analyser, sous des conditions contrôlées (chambre de culture), et en plein champ, l'efficacité en traitement de semence de 11 formulations chimiques. Les expérimentations montrent que seules les formulations à base de métalaxyl ou d'oxadixyl assurent un contrôle appréciable du champignon. Celles-ci peuvent assurer une protection totale, sans aucune phytotoxicité sur les plantes, à la dose de 2,5 g de produit commercial par kg de semence pour la formulation '10% métalaxyl+48% mancozèbe' et à la dose de 3 g de produit commercial pour les associations: '10% oxadixyl+56% propinèbe' et '8% oxadixyl+56% mancozèbe+3,2% cymoxanil'.     

Fatty acid and tocopherol patterns of variation within the natural range of the shea tree (Vitellaria paradoxa)

The shea tree, Vitellaria paradoxa, is one of the most economically and culturally important indigenous tree species in the Sudano-Sahelian region. Its seeds contain a vegetable fat, internationally known as shea butter, which is widely used in edible, cosmetic and pharmaceutical sectors. Based on samples from 456 trees distributed in 17 locations across the species natural range from Senegal to Uganda, the fatty acid and tocopherol variation, and its relationship with geographic and climatic variables, was assessed in order to address the pattern and the origin of this variation across the natural range. Significant differences between Western and Eastern regions for oleic, stearic acid, saturated–unsaturated acid ratio and γ-tocopherol were identified that it is postulated maybe a result of genetic drift due to the evolutionary history of shea tree populations. Within regions the difference among stands was significant for most constituents; however the major part of the variation was observed among trees within stand (53–90 %). Relationships with climatic variables were not verified, weakening evidence for clinal variation hypotheses suggested by previous studies.     

Comparison of marker- and pedigree-based methods for estimating heritability in an agroforestry population of Vitellaria paradoxa C.F. Gaertn. (shea tree)

We implemented a regression-based method between pairwise relatedness estimated from markers and phenotypic similarity to estimate heritability of traits related to leaf size and morphology in a wild tree population (Vitellaria paradoxa C.F. Gaertn.: shea tree). We then compared the results with heritability estimated with a classical pedigree-based method. We tested both approaches in an agroforestry population of this tree species, a very important one and abundant in the Sudano-Sahelian zone of Africa. Twelve microsatellite loci were used to estimate pairwise relatedness after selection of estimator coefficients based on Monte Carlo simulation. The regression-based method applied to 200 individuals did not display a significant trend with physical distance between trees for relatedness as well as for actual variance of relatedness. In consequence, estimates of narrow-sense heritability of traits related to leaf size were not significant. The pedigree-based method using a progeny test with 39 families and 15 individuals per family from the same population showed high and significant estimates of narrow-sense heritability for the same traits (h² = 0.36–0.95), demonstrating a marked genetic variation within the population. This discrepancy between methods stresses the poor performance of the molecular marker-based method. This can be explained by the absence of fine-scale structure within the agroforestry population of shea trees, other parameters being consistent with recommended values. The regression-based method does not seem well adapted to the agroforestry tree population. New experiments in tree populations and theoretical approaches are needed to evaluate the real potential of the marker-based methods.     

Evaluation of decay resistance of wood products made from borax-impregnated wood and bonded with a formaldehyde-free cornstarch and tannin adhesive

? At present, the production of wood composites mainly relies on the petrochemical-based and formaldehyde-based adhesives such as phenol-formaldehyde (PF) resins and urea-formaldehyde (UF) resins, which are non-renewable and therefore ultimately limited in supply.

? This paper concerns the decay resistance of wood products bonded with a new, environment-friendly adhesive derived from abundant and renewable cornstarch and tannin. To improve the total resistance of the composite against both Coriolus versicolor and Coniophora puteana rot fungi, borax (di-sodium tetraborate) was added in proportions of 0.5%, 1% and 2% (w/w) to the cornstarch-tannin adhesives.

? The results show that increasing the concentration of borax in the adhesive decreased the mechanical properties of the composite. The best way to avoid this problem was to use wood impregnated with borax.

? Biodegradation studies were conducted on new composites, first without any treatment, followed by borax at 0.5% aqueous solution treatment. The results show that wood impregnated with borax, in the presence of tannin and sodium hydroxide in the adhesive improves the total resistance of the wood composite against both Coriolus versicolor and Coniophora puteana rot fungi.

     

Modelling the transmission of Echinococcus granulosus in dogs in the northwest and in the southwest of Morocco

Echinococcus granulosus (E. granulosus) infection was studied in 151 dogs in two regions of Morocco: 68 dogs in the northwest (Loukkos) and 83 dogs in the southwest (Tiznit). The mean prevalence rates of echinococcosis in dogs were 58.82% (46.23-70.63%) in Loukkos and 55.42% (44.10-66.34%) in Tiznit and the mean abundances of E. granulosus per dog were 75 (59-93) and 547 (504-595), respectively. The mean abundance of E. granulosus in dogs was fitted to a negative binomial distribution by the maximum likelihood techniques to define parameters. E. granulosus was aggregated in dogs in the two regions. The prevalence of infection and the abundance of E. granulosus in dogs were fitted to mathematical models in order to determine if the parasite population is partly regulated by definitive host immunity. The best fit was obtained with the models assuming the presence of immunity. The mean time of exposure to infection was similar in the two regions and ranged from 8 months to about 2 years. The infection pressures (number of E. granulosus) obtained per dog each year were 65 (8-294) in Loukkos and 476 (316-886) in Tiznit. The proportion of dogs susceptible to infection was still high along the life of the dogs in Loukkos, while it was not different from zero in old dogs of Tiznit.     

Viral encephalopathy and retinopathy in aquaculture: a review

Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a major devastating threat for aquatic animals. Betanodaviruses have been isolated in at least 70 aquatic animal species in marine and in freshwater environments throughout the world, with the notable exception of South America. In this review, the main features of betanodavirus, including its diversity, its distribution and its transmission modes in fish, are firstly presented. Then, the existing diagnosis and detection methods, as well as the different control procedures of this disease, are reviewed. Finally, the potential of selective breeding, including both conventional and genomic selection, as an opportunity to obtain resistant commercial populations, is examined.