The influence of anaerobic muscle activity,maturation and season on the flesh quality of farmed turbot

In order to test seasonal, rearing, maturing and anaerobic muscle activity effect on the flesh quality of turbot (Scophthalmus maximus) a total of 80 farmed turbot from three different strains from reared under natural or continuous light were killed by a percussive blow to the head in November (winter, Icelandic strain), March (spring, Portuguese strain) and June (summer, domesticated strain (France turbot)). To test the effect of anaerobic muscle activity, 10 fish were on each occasion pre rigor filleted, where one fillet was used as a control, while the other fillet was electrically stimulated using a squared 5 Hz, 10 V pulsed DC for 3 min. All pre rigor fillets were measured for pH, weighed, wrapped in aluminum foil and stored in polystyrene boxes with ice. After 7 days of storage the fillets were measured instrumentally for pH, drip loss, colour (CIE L* a* b*) and texture properties such as hardness and shear force, while fillet shrinkage and colour (RBG) were evaluated with computer imaging on photographs from a standard lightbox. Results showed that softness of the flesh was mainly influenced by factors associated with growth, such as season, photoperiod and maturation. Anaerobic muscle activity simulated with electrical stimulation caused an increase in drip loss (<1%) and loss of shear force (<4%), but had no effect on hardness or fillet shrinkage. Computer imaging revealed that muscle contractions related to the electrical stimulus forced out blood from the fillet causing less reddishness for the entire storage period. We conclude that a pH drop upon slaughter associated with anaerobic muscle activity has a minor effect on the flesh quality in the short run, while seasonal/alternatively genetic effects are predominant.     

Red drum <Emphasis Type="Italic">Sciaenops ocellatus</Emphasis> growth and expression of bile salt-dependent lipase in response to increasing dietary lipid supplementation

Sciaenops ocellatus has a long history in aquaculture and many difficulties associated with its commercial culture have been addressed and successfully resolved; nevertheless, further research in lipid nutrition could address more comprehensive questions on the way these nutrients are utilized. The purpose of this study was to evaluate S. ocellatus growth and lipase gene expression in response to increasing dietary lipid supplementation. Four experimental diets were formulated to provide 3, 10, 16, or 23% lipid using menhaden fish oil. Twenty juveniles (mean initial weight 2.3?±?0.1 g) were stocked per aquaria in a recirculating system; each diet was assigned to three aquaria and fed to fish for 6 weeks. At the end of the study, fish fed 3% of dietary lipid were significantly (P?<?0.0001) smaller and showed significantly lower feed efficiency, condition factor, hepatosomatic index, and intraperitoneal fat than fish fed the other diets, but no differences were observed among fish fed 10, 16, or 23% lipid. A straight broken-line regression model for thermal growth coefficient provided an estimated value of 9.4% of dietary lipid as the optimal inclusion level. The bile salt-dependent lipase (BSDL) of red drum was 80.3 kDa. Relative gene expression of BSDL was significantly higher (P?=?0.0007) in fish fed 10% lipid, with no differences among the other dietary treatments. Results provided could help monitor the metabolic status of farmed fish and contribute to optimize diet formulations based on maximum gene expression of BSDL for supplementation of dietary lipid.     

Comparison of different testing schemes to increase the detection <Emphasis Type="Italic">Mycobacterium bovis</Emphasis> infection in Ethiopian cattle

Host immune responses to Mycobacterium bovis (M. bovis) infection are variable at the different severity stages of pathology of the disease. In countries like Ethiopia, where routine screening of bovine TB is not undertaken, the use of tests which measure cellular and antibody responses may help for the maximum detection of infection. In the present study, 701 cattle were tested for bovine tuberculosis (BTB) using comparative intradermal tuberculin (CIDT) test, interferon (IFN)-γ test, and lateral flow assay. The apparent prevalence was 32% when all the three tests were used, but varied from 23 to 25% when a pair of tests was used and from 9% to 15% when a single test was used. Agreement was observed between CIDT and IFN-γ tests both at a cut-off >2 mm (Kappa ± standard Error, k ± SE, 0.129 ± 0.045; 95%CI = 0.041,0.216) and a cut-off >4 mm (k ± SE, 0.094 ± 0.044, 95%CI = 0.008,0.179) while no agreement was observed either between CIDT test and lateral flow assay (k ± SE, −0.04 ± 0.033; 95%CI = −0.104,0.024) or between IFN-γ tests and lateral flow assay (k ± SE, −0.031 ± 0.032; 95% CI = −0.093,0.031). Thus, the use of more than one test leads to the detection of the maximum number of infected animals.     

Litter decomposition and nutrients dynamics in <Emphasis Type="Italic">Nothofagus antarctica</Emphasis> forests under silvopastoral use in Southern Patagonia

The role of environmental variables on litter decomposition and its nutrient release in Nothofagus antarctica forest in Patagonia is poorly understood. Moreover, in these forests under silvopastoral use there are few antecedents. Litter decomposition and nutrient release of grasses and tree leaves were evaluated under different crown cover and two site quality stands during 480 days. Organic matter decomposition varied with crown cover for both types of litter, achieving mean values of 23 and 34% for maximal and minimal crown cover, respectively. Total transmitted radiation was the main environmental factor explaining 61 and 49% of the variation of grass and tree leaves decay rates, respectively. N, P, and Ca were mineralized during first 60 days in decomposing tree leaves and then immobilized without differences between crown cover. The K was immobilized during the evaluated period. In decomposing grass leaves the results varied according to site quality and time. There was a tendency of nutrient mineralization at the first 120 days and then immobilization. The removal of trees for silvopastoral use of N. antarctica may increase litter decomposition by changing the microclimate, but nutrients release or immobilization was mainly affected for their concentration in decomposing material.     

Patterns of change in body condition in wintering Neotropical-Nearctic migratory birds in shaded plantations in the Andes

Despite the widely accepted idea that shaded plantations are valuable habitats for Neotropical migrants in disturbed landscapes, little empirical evidence is available in relation to the quality of this habitat for Neotropical-Nearctic migratory birds in the Andes. We evaluated the suitability of shaded plantations for overwintering Neotropical-Nearctic migratory birds by examining diurnal and seasonal variation in body condition of migrants in these agroforests in the Andes. During October to April 2008–2009 and 2009–2010, we mist-netted eight species of Neotropical-Nearctic migrants in shaded plantations in the Colombian Andes. Body condition improved throughout the day for Cerulean Warbler (Setophaga cerulea), Blackburnian Warbler (Setophaga fusca), Tennessee Warbler (Leiothlypis peregrina), and especially Canada Warbler (Cardellina canadensis). Similarly, body condition improved across the season for Tennessee Warbler, Rose-breasted Grosbeak (Pheucticus ludovicianus), and Summer Tanager (Piranga rubra). Our results provided additional evidence that several common Neotropical migrants, including species of conservation concern such as Cerulean Warbler and Canada Warbler, may improve their body condition in shaded plantations. However, about half of the species assessed in this study did not show any significant improvement in their body condition (e.g. Red-eyed Vireo). Furthermore, on average, species were in poor condition (i.e. body condition scores were negative) in these coffee farms. Thus, the extent to which this agricultural system represents high quality habitat should be looked with caution. Overall, our data contribute novel information on daily patterns of body condition improvement for several common migratory birds in Andean shaded plantations.     

A comparison of measured catchment sediment yields with measured and predicted hillslope erosion rates in Europe

Purpose  

This study aims to understand better the relationship between measured soil loss rates due to sheet and rill erosion (SL), predicted SL rates and measured catchment sediment yields (SY) in Europe.     

Breeding performance of the second generation in some bivoltine populations of <Emphasis Type="Italic">Ips typographus</Emphasis> (Coleoptera Curculionidae) in the south-eastern Alps

The spruce bark beetle, Ips typographus, is one of the most extensively studied European forest pests. Gaps exist in the knowledge about second generation breeding performance in bivoltine populations. In this study, the breeding performance of the second generation was evaluated in three bivoltine populations of I. typographus in the SE Alps. Length of the maternal galleries (from 40.5 to 44.8 mm), population growth rate (PGR; from 0.7 to 3.6), and emerged adults per m² (from 669 to 1,570 insects/m²) varied among populations and were negatively correlated with bark colonisation density. Pheromone traps set up in the three investigated forests differed in the number of trapped beetles, with mean captures ranging between 5,310 and 19,850 insects per trap. The populations giving the highest captures in the traps showed the lowest bark colonisation density (248 vs. 489 maternal galleries per m²) and the best breeding performance. The populations of parasitoids and predators corresponded to just 1–9 and 2–10% of the emerging I. typographus adults, respectively, and phloem temperature never reached thresholds lethal to I. typographus. Interspecific competition was negligible, whereas intraspecific competition was found to be the main factor affecting the breeding performance of the second generation, although with different intensity according to the colonisation density. It is hypothesised that competition with the first generation and spring precipitation influence the number of suitable hosts available to the second generation.     

The use of the first industrial X-ray CT scanner increases the lumber recovery value: case study on visually strength-graded Douglas-fir timber

Key message

Industrial computed tomography scanning of logs provides detailed information on timber quality prior to sawing. A sawing simulation—considering log rotation angle and knot size accuracy—revealed an average value increase of up to 20% for the best angle compared to the conventional horns-up position.

Context

Computed tomography (CT) scanning has the potential to improve the value of products sawn from logs and meets the increasing demands of the wood industry for detailed information on log quality prior to processing.

Aims

In a validation step, automated measurements of knot cluster variable DAB (DIN 4074-1:2012-06) using CT were compared with manual measurements. In a second optimization step, the hypothesis that the value of the sawn products is increased by sawing at the best rotation angle as opposed to the horns-up position was tested.

Methods

A sample of 36 Douglas-fir logs were scanned in an industrial CT scanner, and sawn into boards. Knots on the boards were manually measured, and compared with the corresponding knots on virtual boards created from the CT data. The error of the DAB was measured by comparing CT data to manual measurements. An optimized sawing simulation was performed, using the measured DAB error to account for CT measurement errors, as well as a rotational error to account for errors in the log turning equipment. Using the results of the sawing simulation, Monte Carlo simulations were performed to show the potential and benefit of an industrial CT scanner.

Results

The three largest DABs measured by the CT showed good correlation to the measurements on the manual boards. The simulation revealed an average increase of value from 4 to 20% compared to the conventional horns-up position depending on the relative price differences between the strength grades.

Conclusion

By using a CT scanner to optimize sawing, sawmill owners can process logs in a better way to produce final products with increased added value.

     

Sterile insect technique and <Emphasis Type="Italic">Wolbachia</Emphasis> symbiosis as potential tools for the control of the invasive species <Emphasis Type="Italic">Drosophila suzukii</Emphasis>

Drosophila suzukii, a vinegar fly originated from Southeast Asia, has recently invaded western countries, and it has been recognized as an important threat of a wide variety of several commercial soft fruits. This review summarizes the current information about the biology and dispersal of D. suzukii and discusses the current status and prospects of control methods for the management of this pest. We highlight current knowledge and ongoing research on innovative environmental-friendly control methods with emphasis on the sterile insect technique (SIT) and the incompatible insect technique (IIT). SIT has been successfully used for the containment, suppression or even eradication of populations of insect pests. IIT has been proposed as a stand-alone tool or in conjunction with SIT for insect pest control. The principles of SIT and IIT are reviewed, and the potential value of each approach in the management of D. suzukii is analyzed. We thoroughly address the challenges of SIT and IIT, and we propose the use of SIT as a component of an area-wide integrated pest management approach to suppress D. suzukii populations. As a contingency plan, we suggest a promising alternative avenue through the combination of these two techniques, SIT/IIT, which has been developed and is currently being tested in open-field trials against Aedes mosquito populations. All the potential limiting factors that may render these methods ineffective, as well as the requirements that need to be fulfilled before their application, are discussed.