Spanish Journal of Agricultural Research
Not a member yet
2067 research outputs found
Sort by
Inhibitory action of Lippia gracilis Schauer essential oil on pathogenic bacteria and its effects as a growth promoter on quail
No full textAim of the study: To examine the in vitro sensitivity of Salmonella sp. and Escherichia coli strains to the microbial activity of Lippia gracilis Schauer essential oil (LGSEO) and to determine the optimal level of LGSEO as a growth promoter in diets for Japanese quail up to 35 days of age.Area of study: São Cristovão, Sergipe, Brazil.Material and methods: A total of 504 female Japanese quails (Coturnix coturnix japonica) at an initial average body weights of 6.80±0.10 g was allotted to one of six treatments (0, 100, 200, 300, 400 mg/kg of LGSEO and a diet containing 500 mg/kg of bacitracin methylene disalicylate) in 7 replicates, using 12 birds per experimental unit.Main results: In the age period of 21 to 35 days, feed intake declined linearly (p=0.04) and feed efficiency improved (p<0.01), whereas no changes were observed in production performance (p>0.05). The estimated (p=0.01) maximum relative weights of proventriculus and pancreas were obtained at the LGSEO inclusion levels of 196.5 and 251 mg/kg, respectively. Inclusion of 100 to 300 mg/kg of LGSEO in the diet reduced the total Salmonella sp. bacterial count.Research highlights: The use of 196.5 mg/kg of LGSEO in the diet of Japanese quail improved production performance and organ development and demonstrated potential antimicrobial capacity against Salmonella sp. bacteria. Due its pharmacological composition, LGSEO can potentially substitute to antimicrobials, because contains thymol and carvacrol as main active constituents
Effect of microencapsulated phenolic compound extracts of Maclura tinctoria (L.) Steud on growth performance and humoral immunity markers of white leg shrimp (Litopenaeus vannamei, Boone, 1931) juveniles
No full textAim of study: The effect of microencapsulated phenolic compound extracts of Maclura tinctoria (MTBE) on growth performance and humoral immunity markers of the white leg shrimp Litopenaeus vannamei juveniles (0.5 ± 0.2 g initial weight) was studied.Area of study: M. tinctoria was collected from Hampolol, Campeche, and Arroyo del Agua, Culiacan, Sinaloa, Mexico.Material and methods: Three MTBE inclusions (0.5, 1, and 2.5 g MTBE/kg, Purina®) were compared with a control commercial feed (Purina®) during 30 days. Nine phenolic acids, nine flavonols, four dihydro-flavonoids, four flavones, and seven unidentified phenolic compounds were determined fin the MTBE using a Perkin Elmer® HPLC chromatograph and diode array-detection.Main results: The mean concentrations of total phenolic compounds, total flavonoid compounds, and condensed tannins were 198.05 ± 5.59 mg gallic acid equivalent (GAE) g-1 dw, 78.57 ± 1.80 quercetin equivalent g-1, and 28.32 ± 0.33 mg epicatechin equivalent g-1, respectively. The ferric reducing antioxidant power and the total antioxidant capacity, respectively, averaged 28.32 mg GAE mL-1 and 10.9 mg ascorbic acid equivalent mL-1. Survival, weight gain, and specific growth rate of L. vannamei were similar among the experimental diets. The dietary inclusion of MTBE at 0.5 g/kg of food showed significant higher (p < 0.05) plasma hemocyte lysate protein (1.35 ± 0.055 µg mL-1), prophenoloxidase (0.47 ± 0.15, Abs. 492 nm), and superoxide anion (O2.-) activity (0.21 ± 0.07, Abs. 630 nm).Research highlights: The supplementation of MTBE at 0.5 g/kg of food could be considered as a potential alternative additive for L. vannamei diet in the juvenile production, since it improved the response of the humoral immunity markers at post larval life stages, when cultivated shrimp are more susceptible to be infected by pathogens
Virulence and indole-3-acetic acid (IAA) biosynthesis ability of Turkish Pseudomonas savastanoi pv. savastanoi isolates and susceptibility of some native olive genotypes
No full textAim of study: To evaluate the virulence and indole-3-acetic acid (IAA) biosynthesis ability of several Turkish P. savastanoi pv. savastanoi isolates and the susceptibility of some native genotypes to olive knot.
Area of study: The Aegean, Marmara, and Mediterranean Regions of Turkey.
Material and methods: 101 isolated bacteria were identified on the basis of biochemical, PCR for amplification of the bacterial iaaL gene, and pathogenicity tests. The virulence of the isolates was determined in a randomized experimental trial carried out by stem inoculation of pot-grown seedlings of olive (cv. ‘Manzanilla’) in the growing chamber. The amounts of IAA produced by the isolates were determined colorimetrically. The susceptibility of native olive genotypes was evaluated on 2-yr old plants inoculated with two distinct strains.
Main results: Tested P. savastanoi pv. savastanoi isolates showed significant differences in virulence found to be associated with their geographical origin. The isolates produced IAA amounts varied from 148.67 to 0.3 μg mL-1. The geographical variation in IAA biosynthesis ability of the isolates was observed. No correlation (R=0.0225) was determined between virulence and IAA amounts of the isolates. Native olive genotypes indicated different susceptibility levels to the olive knot pathogen. No genotype tested had complete resistance. However, low susceptible genotypes (‘Memecik’, ‘Ayvalık’ and ‘Uslu’) were identified. Some genotypes had variable reactions depending on the isolate used.
Research highlights: The results undergird the differences in the virulence and IAA production of the isolates within the area and also between geographical locations. Genotypes with low susceptibility can be used as genitors in further breeding studies. 
Agronomic and chemical evaluation of hop cultivars grown under Mediterranean conditions
No full textAim of study: Evaluation of the agronomic performance and chemical profile of four hop cultivars grown under Mediterranean conditions.Area of study: The study was undertaken in Bragança, north-eastern Portugal.Material and methods: The newly introduced cultivars (‘Columbus’, ‘Cascade’ and ‘Comet’) were compared with the well-stablished ‘Nugget’. The field experiment was carried out between 2017 and 2019. Dry matter (DM) yield (plant and cones), tissue elemental composition and bitter acid and nitrate (NO3-) concentrations in the cones were assessed.Main results: ‘Comet’ was the most productive cultivar with the highest total DM yield (1,624 to 1,634 g plant-1), cone yield (572 to 633 g plant-1), and dry weight of individual cones (0.28 to 0.79 g cone-1). ‘Cascade’ showed the lowest average total DM yield (723 to 1,045 g plant-1). The year affected the average values of DM yield and the concentration of bitter acids in the cones, with ‘Cascade’ showing the highest sensitivity between cultivars. The concentrations of α and β-acids in the cones were within or close to the normal ranges internationally accepted for all cultivars. ‘Columbus’ exhibited the highest levels of α-acids, ranging between 12.04 % and 12.23%, followed by ‘Nugget’ (10.17–11.90%), ‘Comet’ (9.32–10.69%) and ‘Cascade’ (4.46–8.72%). The nutrient accumulation criteria in cone and leaf tissues seem to be a differentiating factor between cultivars with influence on bitter acid biosynthesis and biomass production.Research highlights: All cultivars showed notable performance in terms of DM yield and bitter acid concentration in the cones when compared to international standards
Artificial neural networks in the prediction of soil chemical attributes using apparent electrical conductivity
No full textAim of study: To use artificial neural networks (ANN) to predict the values and spatial distribution of soil chemical attributes from apparent soil electrical conductivity (ECa) and soil clay contents.Area of study: The study was carried out in an area of 1.2-ha cultivated with cocoa, located in the state of Bahia, Brazil.Material and methods: Data collections were performed on a sampling grid containing 120 points. Soil samples were collected to determine the attributes: clay, silt, sand, P, K+, Ca2+, Mg2+, S, pH, H+Al, SB, CTC, V, OM and P-rem. ECa was measured using the electrical resistivity method in three different periods related to soil sampling: 60 days before (60ECa), 30 days before (30ECa) and when collecting soil samples (0ECa). For the prediction of chemical and physical-chemical attributes of the soil, models based on ANN were used. As input variables, the ECa and the clay contents were used. The quality of ANN predictions was determined using different statistical indicators. Thematic maps were constructed for the attributes determined in the laboratory and those predicted by the ANNs and the values were grouped using the fuzzy k-means algorithm. The agreement between classes was performed using the kappa coefficient.Main results: Only P and K+ attributes correlated with all ANN input variables. ECa and clay contents in the soil proved to be good variables for predicting soil attributes.Research highlights: The best results in the prediction process of the P and K+ attributes were obtained with the combination of ECa and the clay content
A genetic algorithm for resizing and sampling reduction of non-stationary soil chemical attributes optimizing spatial prediction
No full textAim of study: To evaluate the influence of the parameters of the geostatistical model and the initial sample configuration used in the optimization process; and to propose and evaluate the resizing of a sample configuration, reducing its sample size, for simulated data and for the study of the spatial variability of soil chemical attributes under a non-stationary with drift process from a commercial soybean cultivation area.Area of study: Cascavel, BrazilMaterial and methods: For both, the simulated data and the soil chemical attributes, the Genetic Algorithm was used for sample resizing, maximizing the overall accuracy measure.Main results: The results obtained from the simulated data showed that the practical range did not influence in a relevant way the optimization process. Moreover, the local variations, such as variance or sampling errors (nugget effect), had a direct relationship with the reduction of the sample size, mainly for the smaller nugget effect. For the soil chemical attributes, the Genetic Algorithm was efficient in resizing the sampling configuration, since it generated sampling configurations with 30 to 35 points, corresponding to 29.41% to 34.31% of the initial configuration, respectively. In addition, comparing the optimized and initial configurations, similarities were obtained regarding spatial dependence structure and characterization of spatial variability of soil chemical attributes in the study area.Research highlights: The optimization process showed that it is possible to reduce the sample size, allowing for lesser financial investments with data collection and laboratory analysis of soil samples in future experiments
Effects of salt stress on plant growth, abscisic acid and salicylic acid in own-rooted cultivars of Vitis vinifera L.
No full textAim of study: In most areas of vineyards worldwide, cultivars are frequently grafted on specific rootstocks to avoid Daktulosphaira vitifoliae pest attack. Nevertheless, the absence of this pest in Canary Islands allowed the chance to conserve and cultivate traditional or new own-rooted genotypes without the requirement of the rootstocks. To investigate the responses of own-rooted genotypes of Vitis vinifera L. to salt stress conditions, ‘Castellana Negra’ (‘CN’) and ‘Negramoll’ (‘Ne’) were used with the aim to characterize their morphological and physiological responses.Area of study: Canary Islands, Spain.Material and methods: The effects of NaCl stress on growth, abscisic acid (ABA), salicylic acid (SA) and proline were assessed in ‘CN’ and ‘Ne’ under greenhouse conditions.Main results: In ‘CN’, the decrease of leaf number in stressed plants was lower and started eleven days later than in ‘Ne’. Salt stress also reduced stomatal conductance (gs), although such decrease took place earlier in ‘CN’ than in ‘Ne’. ABA and SA concentrations in ‘CN’ leaves were 2-fold higher than those of ‘Ne’. Salt stress increased leaf ABA and SA content in both genotypes, compared to control. In conclusion, ABA and SA appear to be involved in grapevines responses to salinity and suggest that exogenous SA could be useful to mitigate the stress impacts.Research highlights: ‘CN’ exhibited a better response than ‘Ne’ through the delay of salt injury establishment, and the dissimilar responses between ‘CN’ and ‘Ne’ seem to be associated to the higher accumulation of ABA and SA under salt stress
Vine architecture and production control measures to improve the quality of the wine from Shiraz variety (Vitis vinifera L.)
No full textAim of study: Six thinning treatments were studied to improve the chemical composition and quality of grapes of cv. ‘Shiraz’ under two vine architectures (vase and trellis).
Area of study: Spain, from 2015 to 2016.
Material and methods: The following thinning treatments were applied during four consecutive crop seasons: T0, control; T1, removal of 33% of the clusters (75 BBCH stage); T2, removal of 33% of the clusters (85 BBCH stage); T3, removal of the leaves at the base of the branches; T4, removal of the leaves at base of the branches together with removal of 33% of the clusters; T5, grouping of green branches; and T6, grouping of green branches and removal of 33% of the clusters.
Main results: All the treatments increased the luminosity and degree of polymerization, improving the color intensity and stability in the wines. In the musts, the levels of phenolic compounds (from 48.0 and 46.7 mg L-1 in T0 trellis and vase, respectively, to 66.8 and 68.9 mg L-1 in T6 trellis and vase, respectively), anthocyanins and sugars (from 22.0 and 22.1 mg L-1 in T0 trellis and vase, respectively, to 24.3 mg L-1 in T6 trellis and vase), were considerably improved.
Research highlights: Treatments T6 and T4 reported the best results. Branch grouping was more efficient than leaf removal regarding the contents of phenolic compounds. With respect to vine architecture, the results point out small differences, but we recommend the application of the treatments, mainly T4 and T6, under vase architecture. The season effect was mainly observed in the fourth year, probably due to the climatic conditions
Community structure of epigeic arthropods in barley (Hordeum vulgare L.) soils
No full textAim of study: The study of epigeic arthropods provides information on how ecosystems respond to different management practices. Changes in the structure of epigeic groups reflect changes in the ecological status of habitats. We assessed the influence of semi-natural habitats and environmental variables on the dispersion of the epigeic groups.
Area of study: Southwestern part of Slovakia
Material and methods: Between 2018 and 2020, six barley (Hordeum vulgare L.) fields were selected each year. Five pitfall traps were placed on each field and environmental variables (soil pH and moisture, light conditions, soil N, P, K) were analysed. We collected 8,730 individuals belonging to 14 taxonomic groups. The variables of the study sites (habitat, locality name, cadastral area, altitude, coordinates of localities) were also analysed.
Main results: We observed a decrease in the average number of individuals in the direction from pitfall traps 1 (semi-natural areas) to 5 (barley crop) between July and August. The number of individuals was similar in May and June. The dispersion of epigeic arthropods was affected by soil moisture, pH soil, phosphorus, potassium and nitrogen. In the beetles model group, which was represented by the highest number of individuals, we confirmed an increasing number of individuals with increasing values of K, P, N and soil moisture. The neutral pH of the soil was optimal for beetles.
Research highlights: The ecotone rule does not apply during all months, so we have contributed new information about the ecotone rule. Agricultural intensification affects soil arthropods, a taxonomic group with an important role in the functioning of agricultural ecosystems