Search

Copyright of Informacion Tecnica Economica Agraria is the property of Asociacion Interprofesional para el Desarrollo Agrario (AIDA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The major cause of lamb mortality in grazing systems at birth is starvation and/or exposure to cold complex, with hypothermia being a primary contributing factor. In precocial species such as sheep, the ability to produce the heat required to prevent hypothermia during the first 12 h after birth relies heavily on the nonshivering thermogenesis, via brown adipose tissue (BAT). Therefore, insufficient BAT deposits, or inability to metabolize BAT, are the major factors contributing to lamb death resulting from starvation/exposure. Circulating concentration of melatonin is associated with proper amount and functionality of BAT. However, there is limited information on the effect of increased melatonin levels, via maternal supplementation, on fetal BAT deposition. The objective was to establish the effect of melatonin implants (M) in single- and twin-bearing ewes, on fetal BAT deposits. Corriedale ewes were synchronized, superovulated, mated to Suffolk rams, and managed under commercial grazing conditions. Single (S)- and twin (T)-bearing ewes received 0 (M0), 1 (M1), or 2 (M2) commercial 18-mg melatonin implants (Regulin) at 100 d of gestation (n = 8 per group). Ewes were euthanized at d 140 of gestation, and total fetal perirenal fat (BAT) was excised and weighed. The effect of litter size (S vs. T), number of implants (M0, M1, or M2), and their interaction on fetal biometrics were analyzed using ANOVA. A rank × treatment interaction (P = 0.002) was observed for total BAT, where SM2 fetuses tended to have 18% more BAT compared with SM0 (P = 0.1) and SM1 fetuses (P = 0.09; 22.8 ± 1.6 vs. 19.3 ± 1.5 or 19.2 ± 1.5 g), whereas TM1 fetuses had approximately 35% more BAT compared with TM0 (P = 0.0002) and TM2 fetuses (P = 0.0003; 22.9 ± 1.1 vs. 17.1 ± 1.0 or 16.9 ± 1.1 g). Single and twin M2 fetuses tended to be 5 to 8% heavier compared with single and twin M0 and M1 fetuses (4.1 ± 0.1, 3.8 ± 0.1, and 3.9 ± 0.1 kg, respectively; P = 0.09). In addition, M2 fetuses, compared with M0 and M1 fetuses, showed greater fetal thorax diameter (34.6 ± 0.4, 33.8 ± 0.3, and 33.9 ± 0.3 cm, respectively; P = 0.047) and presented a trend for increased crown-rump length (44.1 ± 0.5, 43.0 ± 0.4, and 42.6 ± 0.5 cm, respectively; P = 0.056). These results indicate that maternal melatonin implants from d 100 of gestation increases BAT deposition, especially in twin fetuses, and may increase BW. Both effects may have important implications for newborn lamb survival under commercial grazing conditions. Funded by CONICYT project number 11150998. [ABSTRACT FROM AUTHOR]

Quality labels are useful tools to differentiate food products, but only if consumers recognise them and associate them with specific characteristics. An online survey was conducted to investigate whether Chilean consumers knew about Novillo de Osorno, for which a quality label is being developed. The survey was divided into five blocks: lifestyles, meat consumption and purchase habits, meat choice behaviour, knowledge about Novillo de Osorno, and consumers' socio-demographic information. The place of residence and consumer gender, age, or income were important cues in defining consumers' lifestyles, meat consumption and purchase habits. Respondents could be grouped into three main groups: 1. Younger people: urban with medium-high incomes, which search only for pleasure; 2. Foodies uninvolved and Females uninvolved: females with the highest income level that chose food for nutritional reasons; and 3. Traditional people: men older than 55 with low incomes, living in the Northern areas and interested in taste and in the meat's origin. Nearly 60% of respondents had never heard about Novillo de Osorno. Hence, the supply chain has an opportunity to extend the market. Since price and confidence in the origin are important cues, they must be considered in the design of promotion strategies.

Proliferation of Phormidium biofilms in rivers is becoming a worldwide sanitation problem for humans and animals, due to the ability of these bacteria to produce anatoxins. To better understand the environmental conditions that favor the development of Phormidium biofilms and the production of anatoxins, we monitored the formation of these biofilms and their toxins for two years in the Tarn River, biofilms from which are known to have caused the deaths of multiple dogs. As previously observed in New Zealand, Phormidium biofilm development occurred in riffle areas. The coverage of these biofilms at the bottom of the river exhibited strong spatial and temporal variations, but was positively correlated with water temperature and depth. Anatoxin- a was detected in less than 50% of the biofilms. The concentrations of these toxins in the biofilms exhibited high spatiotemporal variability, with the highest concentrations being recorded at the end of the summer period at the upstream sampling sites. These findings suggest that the maturity of the biofilms, combined with the local environmental conditions, have an impact on the production of anatoxin, making risk assessment for these benthic proliferations challenging.

River biofilms dominated by Phormidium (cyanobacteria) are receiving increased attention worldwide because of a recent expansion in their distribution and their ability to produce neurotoxins leading to animal mortalities. Limited data are available on the composition and structure of bacterial communities (BCs) associated with Phormidium biofilms despite the important role they potentially play in biofilm functioning. By using a high-throughput sequencing approach, we compared the BCs associated with Phormidium biofilms in several sampling sites of the Tarn River (France) and in eight New Zealand rivers. The structure of the BCs from both countries displayed spatial and temporal variations but were well conserved at the order level and 28% of the OTUs containing 90% of the reads were shared by these BCs. This suggests that micro-environmental conditions occurring within thick Phormidium biofilms strongly shape the associated BCs. A strong and significant distance-decay relationship (r p  = 0.7; P = 0.001) was found in BCs from New Zealand rivers but the Bray-Curtis dissimilarities between French and New Zealand BCs are in the same order of magnitude of those found between New Zealand BCs. All these findings suggest that local environmental conditions seem to have more impact on BCs than dispersal capacities of bacteria.

In fjord systems, Harmful Algal Blooms (HABs) not only constitute a serious problem when affecting the wildlife and ecosystems, but also human health and economic activities related to the marine environment. This is mostly due to a broad spectrum of toxic compounds produced by several members of the phytoplankton. Nevertheless, a deep coverage of the taxonomic diversity and composition of phytoplankton species and phycotoxin profiles in HAB prone areas are still lacking and little is known about the relationship between these fundamental elements for fjord ecosystems. In this study, a detailed molecular and microscopic characterization of plankton communities was performed, together with an analysis of the occurrence and spatial patterns of lipophilic toxins in a HAB prone area, located in the Southeastern Pacific fjord region. Microscopy and molecular analyses based on the 18S rRNA gene fragment indicated high diversity and taxonomic homogeneity among stations. Four toxigenic genera were identified: Pseudo-nitzschia, Dinophysis, Prorocentrum, and Alexandrium. In agreement with the detected species, liquid chromatography coupled with mass spectrometry revealed the presence of domoic acid (DA), pectenotoxin-2 (PTX-2), dinophysistoxin-2 (DTX-2), and 13-desmethyl spirolide C (SPX-1). Furthermore, a patchy distribution among DA in different net haul size fractions was found. Our results displayed a complex phytoplankton-phycotoxin pattern and for the first time contribute to the characterization of high-resolution phytoplankton community composition and phycotoxin distribution in fjords of the Southeastern Pacific region., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Epilithic river biofilms are complex matrix-enclosed communities harboring a great diversity of prokaryotic and eukaryotic microorganisms. Interactions between these communities and the relative impacts of environmental factors on their compositions are poorly understood. In this study, we assessed the spatio-temporal variation in the diversity and composition of bacterial and microeukaryotic communities within biofilms in a French river. Significant changes were found in the composition of these microbial communities over the sampling period and between the upstream and downstream stations. In addition, the beta diversity of the bacterial community tended to decrease along the river, mostly as a result of turnover. These changes could be caused by the different water temperatures and geological and hydrological river contexts at the sampling sites (from karst landscape to river plain). Finally, our network analysis showed multiple correlations among dominant OTUs. Among them, negative correlations between Rhodobacteraceae and two other dominant groups of photosynthetic microorganisms (cyanobacteria and diatoms) were particularly interesting, which raises the question of what environmental factors trigger the changes occurring in benthic microbial photosynthetic communities.

Over the last decade reports of animal poisoning following accidental consumption of neurotoxin-producing benthic cyanobacteria (mainly Phormidium spp.) have increased. There is a need for rapid and cost-effective tools to survey benthic cyanobacteria. In this study we assessed the performance of the BenthoTorch, a fluorometric probe that provides in situ estimations of cyanobacteria, diatoms and green algae biomass in biofilms. Biofilms (n = 288) were analysed from two rivers in France and eight in New Zealand. Correlations between chlorophyll-a measured using the BenthoTorch and spectrophotometry were higher for thin (<2 mm) compared to thick (>2 mm) biofilms (r(2) = 0.58 and 0.27 respectively; p < 0.001). When cyanobacteria represented less than 50% of the total biomass (based on biovolumes), microscopic and BenthoTorch compositional estimations were significantly correlated (r(2) = 0.53, p < 0.001). Conversely, there was no correlation when cyanobacteria exceeded 50% of the total biomass. Under this scenario diatoms were overestimated. Our results suggest that the observed biases occur because the BenthoTorch only measures the upper biofilm layer and it underestimates the biomass of phycoerythrin-containing cyanobacteria. To improve the performance of this sensor and render it a useful tool for a rapid evaluation of benthic cyanobacterial biomass in rivers, we propose that: (i) the algorithms based on the LEDs responses currently available on this tool need revision, (ii) new excitation wavelengths should be included that allow the fingerprints of phycoerythrin-containing cyanobacteria to be discriminated, and (iii) a sensor that penetrates the biofilms is needed to obtain more accurate estimates of cyanobacterial biomass., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Cyanobacteria-dominated microbial mat communities thrive widely and year round in coral reefs and tropical lagoons, with periodic massive development of benthic blooms. We studied the diversity and spatiotemporal variation of the cyanobacterial dominance in mats of the shallow lagoon of La Réunion Island in the Indian Ocean by means of denaturing gradient gel electrophoresis and cloning-sequencing approaches targeting the 16S rRNA gene, combined with macromorphological and micromorphological characterization of corresponding phenotypes. The mat-forming cyanobacteria were highly diversified with at least 67 distinct operational taxonomic units identified in the lagoon, encompassing the entire morphological spectrum of the phylum Cyanobacteria, but with striking dominance of Oscillatoriales and Nostocales. It appeared also that selective pressures acting at different geographical scales have an influence on the structure and composition of these mats dominated by cyanobacteria. First, large changes were observed in their diversity and composition in relation to local changes occurring in their environment. Second, from the data obtained on the richness and composition of the mats and from the comparison with similar studies in the world, tropical mats seem to display wider cyanobacterial richness than in temperate and cold areas. Moreover, these tropical mats share more species with mats in other tropical regions than with those in temperate and cold climatic regions, suggesting that marine cyanobacteria in biofilms and mats display a biogeographic structure.