Physiometabolic responses to road transport in weaned piglets for a short period and the effects of straw bedding

The aim of the study was to evaluate the physiometabolic responses to stress in hybrid suckling piglets that were weaned and transported at different ages on a paved road under two vehicle conditions: with and without a layer of straw bedding. The piglets were weaned and transported at the following ages: 8, 15 and 22 days. The duration of each trip was 1 h. The piglets in each group were further divided into two sub‐groups for two distinct experimental transport conditions: (1) over the road with straw bedding; and (2) over the same road but without straw bedding. A total of three repetitions were performed for each experimental condition. In order to assess their responses to weaning‐ and transport‐induced stress, the study evaluated a thorough physiometabolic blood profile. The 8‐ and 15‐day‐old piglets transported without straw bedding showed increases in their pCO2, blood glucose, blood lactate levels and the percentage of hematocrit, but a decrease of pO2 upon arrival (P < 0.05). In contrast, the 22‐day‐old piglets transported on the same road with straw bedding were able to re‐establish their blood concentrations of lactate, pCO2, pO2, Na+, K+, Ca2+ and pH during the trip (P < 0.05).     

QTL analysis and mapping of pre-harvest sprouting resistance in Sorghum

One of the most important agronomic problems in the production of sorghum [Sorghum bicolor (L.) Moench] in humid climates is pre-harvest sprouting (PHS). A molecular linkage map was developed using 112molecular markers in an F₂ mapping population derived from a cross between IS 9530 (high resistance to PHS) and Redland B2 (susceptible to PHS). Two year phenotypic data was obtained. By means of interval mapping analysis, two significant QTL were detected in two different linkage groups with LOD scores of 8.77and 4.39. Each of these two QTL individually explained approximately 53% of the phenotypic variance, but together, in a two-QTL model, they explained 83% of the phenotypic variance with a LOD score of 12.37.These results were corroborated by a one-way ANOVA in which the four flanking markers of the most likely QTL positions displayed highly significant values in theF-test, and significant variation in trait expression was associated with marker genotypic classes. The four markers with highest effect in the one-way ANOVA were also detected in the second year replication of the F₂ population, and significant genotype × environment interactions was observed. The putative relationship between PHS resistance in sorghum and the maize Vp1 gene is also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Characterisation of woody Medicago (sect. Dendrotelis) species, on the basis of seed and seedling morphometry

The three species belonging to the sect. Dendrotelis of the genus Medicago: M. arborea L., M. citrina (Font Quer) Greuter, and M. strasseri Greuter, Matthäs & Risse, were characterized using 12 morphometrical characters of seeds and 20 of seedlings. These species have interest for the regeneration of degraded lands in semi-arid climates. M. arborea presents the largest phenotypic variability and is dispersed throughout the Mediterranean basin, while the other two species are endemic to a very reduced area, M. citrina, in Columbretes Islands and Cabrera Islands (Spain) and M. strasseri in Crete. Several populations of M. arborea were measured, in order to compare the intraspecific variability within M. arborea with the differences among all three species. The multivariate analysis of the data used characters that were independent of the size of the studied organs. The three species were clearly differentiated on the basis of seed characters. On the other hand, seedling characters distinguished M. citrina from the other two species, but M. strasseri and the populations of M. arborea were intermingled. In spite of this, we have described relevant morphological differences among M. arborea, M. strasseri and M. citrina, which are consistent with other ecological or bromatological differences. The study supports that the three accessions merit to be considered as three different species.     

Distribution of IS900 restriction fragment length polymorphism types among animal Mycobacterium avium subsp. paratuberculosis isolates from Argentina and Europe

Sixty-one Mycobacterium avium subsp. paratuberculosis isolates from cattle and deer from the Buenos Aires province, an important livestock region in Argentina, were typed by restriction fragment length polymorphisms (RFLP) analysis based on IS900. Four different RFLP patterns (designated ‘A’, ‘B’, ‘C’ and ‘E’) were identified in BstEII digests of genomic DNA. The most frequently observed type, pattern ‘A’, was found in 46 isolates (75%). The second, pattern ‘E’, included 8 isolates (13%), while the third, pattern ‘B’, included 6 isolates (10%). Pattern ‘C’ was found for only one isolate. All of the deer isolates were classified as pattern ‘A’, while cattle isolates represented all four RFLP patterns. Twenty-one isolates representing the four different BstEII-RFLP patterns were digested with PstI. Twenty isolates showed identical PstI-RFLP pattern. BstEII-RFLP patterns from Argentine cattle and deer were compared with patterns found in cattle, goat, deer, rabbit, and human isolates from Europe. The most common pattern in Argentina, pattern ‘A’, was identical to a less frequently occurring pattern R9 (C17) from Europe. The other Argentine patterns ‘B’, ‘C’ and ‘E’, were not found in the Europe. These results indicate that the distribution of M. avium subsp. paratuberculosis genotypes in the Buenos Aires province of Argentina is different from that found in Europe.     

Diversity and genetic population structure of the Brazilian sharpnose shark Rhizoprionodon lalandii

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Effects of chemical and handling exposure on fatty acids, oxidative stress and morphological welfare indicators in gilt-head sea bream (Sparus aurata)

This work investigates the changes in the morphological traits, body composition, body fat and oxidative stress of Sparus aurata under two stress conditions: a low weekly exposure to the pesticide Diuron and chronic handling stress. The fish exposed to handling stress showed lower values in the morphological traits and perivisceral fat, whereas chemical stress induced a decrease in the percentage of muscle and carcase and an increase in the percentage of spleen and hepatosomatic index. The two stress situations produced changes in the FRAP (ferric reducing antioxidant power) levels in all organs studied with a particularly marked response for Diuron in the gill. No significant differences in the ROS (reactive oxygen species) level were found for the digestive tract or the gill. In muscle, only Diuron produced a significant increase in ROS, while in liver, both treatments increased the ROS levels. This supports the oxidative stress sensitivity to chemical stress and shows that also could be an appropriate indicator of handling stress. The morphological indexes and body components examined could be practical and easy welfare indicators. Nevertheless, further works must be needed to use under the production conditions in fish farms.     

Formulation of an Alternative Culture Medium for Arthrospira maxima (Spirulina) Based on “Tequesquite,” a Traditional Mineral Resource

Culture media formulation for Arthrospira maxima (formerly designated as Spirulina maxima) production is a constraining factor. Use of synthetic media could be expensive because most of the commercial strains require salinity conditions higher than 20 g/L. In this study, a traditional, pre‐Hispanic mineral resource, known as “tequesquite,” was used as the base for the formulation of an alternative and low‐cost culture medium. Tequesquite is available from outcrop areas located in the basin of the former Lake Texcoco, where A. maxima thrived in pre‐Hispanic times. The effect on the biomass production of different tequesquite‐based formulations, varying N, P, and , was tested and compared with results obtained with Zarrouk's medium (ZM). Growth of biomass in some alternative formulations showed no significant differences compared with ZM. Production in a bubble‐column photobioreactor of the alternative medium reached a maximum of X = 2570.4 mg/L dry weight, compared with X = 2931.4 mg/L dry weight obtained with ZM. The proposed tequesquite‐medium formulation has equivalent N and P concentrations as ZM, but only 50% of NaHCO₃, thus reducing the medium's cost. In addition, it avoids the use of seawater or NaCl to provide the salinity condition required for the adequate growth of Arthrospira.     

Neotropical freshwater fishes imperilled by unsustainable policies

Neotropical freshwater fishes are the most diverse on the planet (>5,500 species), although nations in Latin America have been negligent regarding their conservation. National policies have historically encouraged unsustainable practices, and recent decades have witnessed a sharp increase in harmful activities. Our aim with this review was to expose this situation and illustrate how national policies constitute the main threat to freshwater fish biodiversity. We explain that the most devastating, pervasive and systemic threats are rooted in official policies, particularly unsustainable activities (e.g. hydropower, water diversion, mining, aquaculture, agriculture and fishing), poor management/conservation (e.g. fish stocking and passages) and harmful legislation (e.g. poor licensing, non‐native species). We provide a broad portrait of the Neotropical scenario, where unsustainable policies have caused considerable damage to freshwater ecosystems, and focus on major examples from Brazil, where development projects have caused large‐scale losses to fish biodiversity. Such modus operandi of human development is incompatible with the persistence of biodiversity, and no simple solution is available to correct or minimize its effects. The current situation demands a profound behavioural shift towards better practices and policies, or these multiple high‐impact activities will continue eroding freshwater fish biodiversity and impairing essential ecosystem services.