Spanish Journal of Agricultural Research
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Does plant growing condition affects biodistribution and biological effects of silver nanoparticles?
No full textAmong the many different types, silver nanoparticles (AgNPs) are the most commercialized and applied engineered nanoparticles in a wide range of areas, including agriculture. Despite numerous studies on their safety and toxicity of AgNPs, data on their effect and interactions with terrestrial plants are largely unknown. This study aimed to investigate the effect of growing conditions on the response of pepper plants (Capsicum annuum L.) to citrate-coated AgNPs. Growth parameters, biodistribution, and defence response were examined in peppers grown hydroponically or in soil substrate. In addition, the effects of nano and ionic form of silver were compared. The leaves and stems of peppers grown in substrate showed a higher bioaccumulation compared to hydroponically cultivated plants. The nano form of silver accumulated to a higher extent than ionic form in both leaves and stems. Both silver forms inhibited pepper growth to a very similar extent either through hydroponic or substrate growing settings. Unlike other studies, which investigated the effects of unrealistically high doses of AgNPs on different plant species, this study revealed that vascular plants are also susceptible to very low doses of AgNPs. Both silver forms affected all parameters used to evaluate oxidative stress response in pepper leaves; plant pigment and total phenolics contents were decreased, while lipid peroxidation and hydrogen peroxide lever were increased in treated plants. Similar biological effects of both nano and ionic Ag forms were observed for both substrate and hydroponic growing systems
Comparison of vapour pressure deficit patterns during cucumber cultivation in a traditional high PE tunnel greenhouse and a tunnel greenhouse equipped with a heat accumulator
No full textPlant productivity in protected cultivation is highly influenced by air temperature and humidity. The conditions relating to the moisture content of the air in protected plant cultivation are preferably defined by vapour pressure deficit (VPD), which describes the difference between the maximal and actual water vapour pressure (kPa). VPD is widely used as the parameter describing the climate conditions favourable for the development of fungal diseases and for highlighting conditions unfavourable for plant development. In protected cultivation, both the air temperature and the humidity are influenced by heating systems, and one such system is a heat accumulator, which may store the excessive heat produced during the day by converting the solar energy inside the plastic tunnel, and using it when plant heating is required. The tunnel equipped with a heat accumulator maintained an optimal level of humidity for a longer period, and significantly reduced the time of excessive air humidity. The longest time with an optimal VPD was recorded in August in a tunnel with an accumulator – 30.5% of total time vs. 22.3% of time for control tunnel. The highest difference of total time where the VPD was too low (below 0.2 kPa) was recorded in July – 12.4% of time in a tunnel with an accumulator vs. 39.1% of time for control tunnel. The highest difference of total time with an excessive VPD (over 1.4 kPa) was recorded in May – 12.1% of time in a tunnel with an accumulator vs. 17.9% of time for control tunnel. However, a situation beneficial for plant growth occurred every month during the investigated season
Effect of fermented, hardened, and dehulled of chickpea (Cicer arietinum) meals in digestibility and antinutrients in diets for tilapia (Oreochromis niloticus)
No full textAmong the most typical feed sources for tilapia, plants represent a low-cost source in substituting for traditional high-cost feed ingredients. Fermentation, hardening and dehulling are common grains processing techniques to make plant nutrients available and more digestible to fish. Apparent digestibility coefficients (ADC) of dry matter and protein, and antinutrients (phytic acid and tannins) in fermented, hardened and dehulled chickpea (Cicer arietinum) meals were determined for juvenile Nile tilapia (Oreochromis niloticus). The highest ADC was obtained with processed (fermented, hardened and dehulled) chickpea meals compared with non-processed. Results indicated that fermentation increased the protein content by 13.1%, decreased the content of ash and phytic acid (47.5 and 45%, respectively), and increased the ingredient apparent digestibility of dry matter (ADM) by 23.2%, and the ingredient apparent digestibility of protein (ADP) by 41.9%. Dehulling meal increased the protein (5.7%) and lipid (6.4%) content of chickpea grains; decreased fiber, ash and tannin content (75.3%, 19.1%, and 84.5%, respectively); and increased ADM by 12.8%, and ADP by 10.4%. We conclude that fermented, hardened and dehulled chickpea meals represent a potential alternative in diets for juvenile O. niloticus
Rearing, bird type and pre-slaughter transport conditions I. Effect on dead on arrival
No full textThe transport of broilers to slaughter normally results in a small percentage of dead on arrival (DoA) but little is known about the effects of flock thinning or bird weight. A multivariable linear model was used to analyse the incidence of DoA over one year in 1,856 flocks of Ross broilers (9,188 shipments). Each flock was categorized according to broiler type (yellow-skinned females and males, white-skinned females and males and roaster females) and thinning (birds transported after thinning, remaining birds after thinning and non-thinned flocks), in addition to transport distance, waiting time, maximum and minimum daily temperatures, precipitation and maximum wind speed. The overall percentage of DoA was 0.187%. The effect of the daily maximum outside temperature on DoA was quadratic with minimum DoA at 21.5ºC. Arrival time to the slaughterhouse and waiting time increased DoA by 0.0044% and 0.0021% for every 60 min increase, respectively. DoA were higher in males (which were heavier than females), and in the flocks that were previously thinned. An interaction between thinning and bird type was found, so that DoA were higher in previously thinned flocks of male broilers and roaster females. Despite the high incidence of thinning and larger bird weight, the percentage of DoA was comparable to previous studies. This research provides one of the largest detailed analyses of DoA in commercial broiler production in the Iberian Peninsula. The models described allow to quantify how increases in temperature, transport distance, waiting time, bird weight and the practise of thinning can all increase broiler mortality
Determinants of farmer participation in direct marketing channels: A case study for cassava in the Oyo State of Nigeria
No full textImproving rural farmers’ access to direct agricultural markets is required to ensure sustainable supply of food. Rural farmers in the developing world account for the largest share of food supply including cassava. Globally, cassava (Manihot esculenta Crantz) is recognised as an important source of valuable semi-processed industrial raw materials such as ethanol, high-quality cassava flour and starch. However, there is less empirical research on rural farmers’ participation in direct marketing channels in the cassava sector. This study focused on analysing the determinants of farmer participation in direct marketing channels using the case of the cassava sector in the Oyo State of Nigeria. The Bivariate Tobit model was applied in the empirical analysis, based on a primary dataset generated from 400 rural cassava farmers from the Oyo State of Nigeria. The result showed that, in general, farmers sold a higher percentage of their cassava output to processors. The Bivariate Tobit results showed that human capital, physical capital, social capital, and market conditions had significant effects on farmers’ decisions on whether to sell their cassava output directly to processors or middlemen. On the contrary, natural and financial capitals did not significantly affect farmers’ marketing channel decision. The study recommends that policy instruments should target improving road networks in rural areas, enhancing farmers’ access to market information, and increasing membership of farmer association to ensure an active participation of farmers in the direct marketing channels
Short communication: Identification of cultivated and wild Vaccinium species grown in Portugal
No full textVaccinium crops offer a variety of benefits for human health due their high levels of antioxidants. Genetic diversity between two Vaccinium species (sixteen cultivars of Vaccinium corymbosum and three wild populations of Vaccinium myrtillus) were evaluated using Inter Simple Sequence Repeat (ISSR) markers. In V. corymbosum 74 polymorphic markers corresponding to 83.2% of polymorphism were obtained while in V. myrtillus only four polymorphic markers corresponding to 83.2% and 10.6% of polymorphism were observed. The dendrogram obtained showed a clear division into two distinct groups corresponding to the two analyzed species. V. corymbosum group is divided in different sub-clusters based on cultivars pedigree relationships. Twenty-eight specific bands were detected in total; 6 for V. corymbosum and 22 for V. myrtillus. Results allowed the selection of five primers due it potential to detect specific bands in the two species. These markers could be useful for identifying species and cultivars and consequently help in the management of germplasm collections and in breeding programs
The public funding of innovation in agri-food businesses
No full textPublic administrations have in recent years developed programs of public funding for innovation to boost the competitiveness of business. The study of how companies have used these funding sources generates knowledge to improve the design of support for private innovation and to provide advice for innovative companies. This paper investigates these issues in the agri-food sector which is of particular interest as it is comprised mainly of small and medium enterprises with a wide regional presence and interaction with their local environment. A survey on technological innovation was used to estimate panel logit models with random effects, taking as dependent variables three types of funding: regional, state and European Union. The results generally show a positive relationship between innovation efforts and access to public funding, but also significant differences between types of funding and between sectors. Food companies that obtain public funding tend to have a more innovative profile than Agriculture ones. Both types of firm present higher probabilities than others companies when it comes to gaining access to regional funding, though the opposite often occurs in the case of state funding. Firm size is not significant for regional funding and no overlap was detected between regional and state funding. The financial crisis has adversely affected regional and national aid, which experienced a significant decrease in the period from 2008 to 2013
Epidemiological study of honeybee pathogens in Europe: The results of Castilla-La Mancha (Spain)
No full textAs a part of a Pilot Monitoring Program of honey bee health coordinated by the EURL (European Union Reference Laboratory) and according to the criteria established for Spain, 14 apiaries in Castilla-La Mancha were selected at random and sampled during the autumns of 2012-2014 to identify the most prevalent nosogenic agents, potentially those related to the honey bee colony collapse phenomenon. In all the apiaries studied, Nosema ceranae was the most prevalent pathogen detected over the three years, confirming the worldwide spread of this microsporidian, a pathogen that negatively affects honey bee health at an individual and colony level. Trypanosomatids were also very prevalent in honey bee colonies, although the majority of Trypanosomatids detected were not Crithidia mellificae but rather the genetically distinct Lotmaria passim lineage. We also detected Varroa destructor mites, and the particularly high prevalence in 2014 suggests a possible problem regarding mite control in field conditions that requires attention. In agreement with data from other regions, the BQCV and DWV were the most prevalent viruses in honey bee colonies and thus, the Varroa-DVW interaction may be an important cause of bee colony mortality. While there was little evidence of a relationship between the BQCV virus and N. ceranae under field conditions during 2012, this was not the case in 2013 and 2014. Finally, the AKI-complex or LSV-complex was not detected. The information obtained in this study should help orientate future plans for honey bee disease control
Short communication: Genetic parameters for post-weaning visual scores and reproductive traits in Suffolk sheep
No full text The aim of this study was to estimate the coefficients of heritability and genetic correlations among visual scores (conformation, CPW; precocity, PPW; musculature, MPW) and reproductive traits: age at first lambing (AFL) and scrotal circumference (SC) evaluated at 180 days of age in Suffolk lambs. In the statistical model only the additive genetic effect was considered as random effect. The heritability estimates by univariate analyses for CPW, PPW, MPW, AFL and SC were 0.08, 0.12, 0.09, 0.20 and 0.22, respectively. The genetic correlations among AFL and CPW, PPW, MPW were -0.26, 0.19, and 0.08, respectively. The genetic correlation among SC and CPW, PPW, MPW were, respectively, 0.54, 0.88 and 0.86, and between AFL and SC was 0.26. The direct selection for conformation, precocity and musculature at 180 days of age and age at first lambing will provide slow genetic progress due to low heritability estimates. It is possible to obtain genetic gain in sexual precocity through selection on scrotal circumference in Suffolk rams. The favorable genetic correlation among visual scores and SC and between CPW and AFL, indicated the possibility to gain in genetic progress for reproductive traits through indirect selection of the visual scores in Suffolk sheep
Effect of spirulina (Arthrospira platensis) supplementation on tilapia (Oreochromis niloticus) growth and stress responsiveness under hypoxia
No full textSeveral recent studies have shown that Arthrospira sp. supplementation of feeds has a beneficial effect on fish health and growth, but less is known about its possible effects on stress responsiveness. The present study was designed to evaluate using Arthrospira platensis as a feed supplement for Oreochromis niloticus fry, reared in recirculating aquaculture systems. Two isocaloric and isonitrogenous fishmeal-based diets were prepared with 0% and 1% A. platensis and fed to fry, approximately 10 mg live weight at the beginning of the experimental period (n=16 tanks, 8 tanks per treatment), at a feeding rate of 6% live weight, four meals a day for 50 d. The weight gain per tank, specific growth rate and feed conversion ratio were similar among treatments but A. platensis supplementation significantly increased survival (p<0.05). Stress responsiveness was measured in all fish from 12 tanks using a non-invasive two-choice test. All fish from one home tank (n=6 tanks per treatment), were placed into a shaded tank where oxygen levels were slowly reduced. A doorway was then opened to a second illuminated tank with normal oxygen levels and the number of fish that left the home tank were counted. The fish fed A. platensis stayed significantly (p=0.001) longer in the home tank (30.20 min ± 13.22) than controls (17.35 min ± 8.32), suggesting a lower stress responsiveness and a higher tolerance to hypoxia