Clinical, pathological and microbiological profiles of spontaneous enteropathies in growing rabbits

[EN] In a rabbit production facility, health monitoring for enteropathies was performed in 15 production cycles for 20 mo. For each cycle, up to a hundred 35 d old rabbits weaned the same day were randomly selected, reared in the same fattening unit, but separately from the source batch and fed with the same feed except for antimicrobial supplementation. Clinical symptoms and enteric lesions of the selected group were recorded, using two checklists with binomial response (yes/no answer to a list of 54 clinical and enteric variables). The day after weaning, one week later, at the beginning of the enteric symptoms and 4-5 d after the start of the symptoms, inocula from the small intestine and caecum of selected animals were subjected to microbiological, C. spiroforme, Eimeria oocyst and rotavirus antigen detection tests. Representative samples of E. coli and C. perfringens isolates were tested, respectively, for serotype, biotype, eae, afr/2 genes and for a, b1, b2, e, i and enterotoxin toxin genes. The answers to the clinical-pathological variables were subjected to statistical analysis with a cluster analysis programme in order to obtain homogeneous, statistically significant groups of diseased animals (clusters). Then, the clusters were statistically associated with the laboratory outcomes. The cluster to which the enterotyphlitis lesions significantly contributed was associated with E. coli detection, E. coli O103 serotype detection and C. spiroforme ("several elements" variable). C. spiroforme ("rare elements" variable) was significantly associated with a cluster, characterised by a pathological profile consisting of bloating/rumbling noise and liquid content in stomach and caecum, without enteric inflammation. C. perfringens was significantly associated with a cluster, characterised by a pathological profile consisting of dilation/liquid content of small intestine, caecal impaction and mucoid content in the colon. Eighteen out of twenty-fi ve C. perfringens strains, examined for their toxin genotypes, proved to be toxin type A, while 7 out of 25 strains showed the a and b2 toxin genes in combination. The rotavirus antigen and Eimeria oocysts were detected from healthy rabbits (specimens of the day after weaning and one week later) in about 15% of specimens examined, but their presence in the sick animals was not significantly associated with any cluster.This study was supported by a financial contribution from Avitalia, Unione Nazionale Associazioni di Produttori Avicunicoli, Forlì, Italy, as part of the programme entitled “Miglioramento della qualità, della gestione dell’offerta delle produzioni cunicole e di rafforzamento dei rapporti di filiera. Azione 4.3”. Our thanks go to breeder Leta Covelli and Dasco srl for supplying the rabbits, to our colleague Romolo Salini and to Fabrizio Agnoletti of the Istituto Zooprofilattico Sperimentale del Veneto, Trevise, ItalyBadagliacca, P.; Letizia, A.; Candeloro, L.; Di Provvido, A.; Di Gennaro, A.; Scattolini, S.; Pompei, G.... (2010). Clinical, pathological and microbiological profiles of spontaneous enteropathies in growing rabbits. World Rabbit Science. 18(4):187-198. doi:10.4995/wrs.2010.77518719818

Perspectives of RDF use in Decentralized Areas: Comparing Power and Cogeneration Solutions

Present EU trends strive to maximize the resources recovery from municipal solid waste thus minimizing the waste amount to be disposed off. Refuse-derived fuel (RDF) production is considered in some countries to be a priority solution even if current market scenarios and consumers scepticism at present limit its widespread utilization. In this work, a comparison has been carried out of two possible RDF utilization alternatives, with particular reference to territorial districts with low population density. After a brief introduction, in which current RDF combustion technologies are illustrated, two possible plant configurations are considered, one concerning only electric power production; the other one combined heat and power production (CHP), using heat for district heating purposes, resorting to two different architectures: single pass-out condensing turbine and back-pressure turbine. Possible application of these technologies to a case study is then proposed, referring to a central Italy mountain territory characterized by a low population density. Then, an economic evaluation has been carried out. Finally, a parametric study was performed in order to define acceptable values for the sale price of thermal energy and the effect on profitability of the incremental investment needed for the construction of a district heating network

Economics of biomass energy utilization in combustion and gasification plants: effects of logistic variables

The substitution of conventional fossil fuels with biomass for energy production results both in a net reduction of greenhouse gases emissions and in the replacement of non-renewable energy sources. However, at present, generating energy from biomass is rather expensive due to both technological limits related to lower conversion efficiencies, and logistic constraints. In particular, the logistics of biomass fuel supply is likely to be complex owing to the intrinsic feedstock characteristics, such as the limited period of availability and the scattered geographical distribution over the territory. In this paper, the economical feasibility of biomass utilization for direct production of electric energy by means of combustion and gasification-conversion processes, has been investigated and evaluated over a capacity range from 5 to 50MW, taking into account total capital investments, revenues from energy sale and total operating costs, also including a detailed evaluation of logistic costs. Moreover, in order to evaluate the impact of logistics on the bioenergy plants profitability, the effects of main logistic variables such as specific vehicle transport costs, vehicles capacity, specific purchased biomass costs and distribution density, have been examined. Finally, a mapping of logistic constraints on plant profitability in the specified capacity range has been carried out