Spanish Journal of Agricultural Research
Not a member yet
2067 research outputs found
Sort by
Valine in diets for juvenile Nile tilapia (Oreochromis niloticus): growth performance, chemical composition, blood parameters and skeletal muscle development
No full textValine belongs to the group of branched-chain amino acids, has an important structural role and is primarily deposited as body protein. The present study evaluated the effects of valine in diets of juvenile Nile tilapia. A total of 216 juveniles with weight of 21.40 ± 0.42 g and length of 10.07 ± 1.00 cm were distributed into 18 aquarium in a completely randomized design with six treatments and three replicates. Six diets containing 24.30% digestible protein, 3,100 kcal/kg digestible energy, and increasing valine levels (0.54; 0.63; 0.72; 0.81; 0.90; 0.99%) were prepared. The following factors were evaluated: performance, chemical composition, blood hematological and biochemical, and skeletal muscle development. Differences were observed in productive performance between treatments for weight gain, daily weight gain and apparent feed conversion, where inclusion levels from 0.81% to 0.99% provide better performances. According to the equation of quadratic regression, the inclusion of 0.86% of valine provided greater weight gain. Regarding the hematological and biochemical parameters, there were differences among the treatments for hemoglobin, triglycerides, and cholesterol. Not difference was observed for the chemical composition and muscle fiber growth. It is recommended the inclusion of 0.86% of valine in the diet of juveniles of Nile tilapia because it provides greater weight gain
Effect of compost and natural rocks as partial substitutes for NPK mineral fertilizers on yield and fruit quality of ‘Flame’ seedless grapevine grown in two different locations of Egypt
No full textAim of study: To evaluate the use of compost and natural rocks as partial replacement of mineral fertilizers in ‘Flame’ seedless grape vineyards.Area of study: The present work was conducted during three successive seasons (2016, 2017 and 2018), being the first season a preliminary trial on 4-yr old grapes cultivated in two different soil types (sandy and clay) at two different locations, Egypt (Abo Galeb, Giza governorate; EL-Mahala, Gharbia governorate).Material and methods: Treatments were applied as natural raw materials at 20, 40, 60, 80 and 100% out of recommended mineral NPK rate. The mineral fertilizers used were ammonium sulfate (21.6% N), calcium super phosphate (15.5% P2O5) and potassium sulfate (48% K2O). The natural rocks used were phosphate rock (22.0% P2O5) and Feldspar (10.12% K2O). Yield and fruit characteristics and leaf mineral content were determined.Main results: Using compost in combination with natural rocks enriched with NPK mobilization bacteria and mineral NPK enhanced leaf nutrients content and gave the highest yield and cluster weight. This mix also improved berries physical and chemical characteristics. There was an increase in soluble solids content (SSC), SSC/acid ratio, and anthocyanin content, associated with a reduction in nitrate content of the berry juice. The most pronounced effect was related to using 60% mineral fertilization + 40% organic and natural rocks in both vineyard locations.Research highlights: We can reduce the recommended doses of mineral NPK by about 40%, reducing then the soil pollution
Susceptibility of the egg parasitoid Trichogramma achaeae (Hymenoptera: Trichogrammatidae) to selected insecticides used in tomato greenhouses
No full textThe South American tomato moth Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a pest species of great economic importance in tomatoes, both in greenhouses and in open-air crops. This importance has increased in recent years because it has been introduced in many countries in Europe, Africa, and Asia. Insecticides different active ingredients and biological control agents are being used in the control of this pest species. This implies the need to make both groups compatible within IPM programmes. Therefore, the objective of this work was to study the compatibility between different insecticides and the use of the egg parasitoid Trichogramma achaeae Nagaraja and Nagakartti (Hymenoptera: Trichogrammatidae). Three groups of trials were carried out under laboratory and greenhouse conditions. Ten insecticides with the following active ingredient were evaluated: abamectin, azadirachtin, Bacillus thuringiensis, chlorantraniliprole, emamectin, flubendiamide, indoxacarb, methomyl, spinosad, and spiromesifen. In the results, three groups of insecticides were established based on their compatibility with the use of biological control: The first group (abamectin, B. thurigiensis, flubendiamide, indoxacarb and spiromesifen) showed a high degree of compatibility with egg parasitoid releases. The second group (azadirachtin and chlorantraniliprole, and methomyl) presented compatibility problems. Finally, the last group (emamectin, methomyl, and spinosad) did not apper to be compatible. The results found will allow a better application of IPM programmes in tomato crops for the control of this pest species
Multi criteria analysis of the energy potential of agricultural residues: The case study of Međimurje County in Croatia
No full textAim of study: The utilization of agricultural residues may become one of the major sources for production of energy from biomass. The objective of this paper was to analyse the type and quantity of agricultural residues and to determine their energy potential.Area of study: The Međimurje County (north Croatia).Material and methods: The paper analyses three models of sustainable agricultural residues management applying the multi-criteria analysis. The assessment included potentially available quantities of residues in crops, fruit, viniculture and livestock production. For determining the most appropriate model of residues utilisation the multi-criteria analysis was applied.Main results: The results show that total quantities of agricultural biomass amount to 323,912 t with energy potential of 1,092 TJ annually. The largest sustainably available potential of agricultural biomass consists of biomass from arable crops production, with total quantity of 33,670 t followed by 281,233 t of manure from livestock production. The lowest share of potential biomass are pruning residues in fruit and grapevine production with total available residual quantity of 8,109 t. Also, it results from the multi-criteria analysis that a central large scale plant for biogas production is the most feasible facility for such production.Research highlights: The results of this paper provide ground for further development of the models for assessing the sustainability of using agricultural residues, and they can also serve as a basis for assessments of bioenergy projects in specific regions of the European Union
Sensitivity analysis and parameterization of two agricultural models in cauliflower crops
No full textAim of study: The development of a procedure to calibrate the LEACHM and EU-Rotate_N models for simulating water and nitrogen dynamics in cauliflower crops.Area of study: Calibration was performed using experimental data obtained from measurements in a cauliflower crop sited in Valencia (Spain) region.Material and methods: A procedure based on generalized sensitivity indices for time-dependent outputs was used to determine the most influencing model parameters, in order to reduce the number of parameters to be calibrated and to avoid overparameterization. The most influencing parameters were introduced in an optimization process that uses the experimental measurements of soil water and nitrate content to determine its optimal value and obtain calibrated models.Main results: After this analysis, the most important hydraulic parameters found were the coefficients of Campbell’s equation for the LEACHM model and the soil water content at field capacity and drainage coefficient for the EU-Rotate_N model. For the N cycle, the most influencing parameters were those related with the nitrification, humus mineralization rate and residue decomposition for both models. Both calibrated models provided good simulation of soil water content with an error between 5-7%. However, larger errors in soil-nitrate content simulation were found, mainly in the period corresponding to the crop residues incorporation. The prediction of the calibrated models in a different plot gave error values of about 7-9% for soil water content, but for soil nitrate content errors computed were 34% and 58%.Research highlights: After calibration, both models can be used to optimize the farmer water management and fertilization practices in horticultural crops, although in the N case further studies should be performed
Effect of age at first calving and heat stress at parturition on reproductive efficiency and postpartum disorders in Holstein heifers
No full textThe objective of this study was to evaluate the impact of age at first calving (AFC) and climatic conditions at calving on peripartum disorders and reproductive performance in Holstein heifers in a hot environment. A total of 3000 reproductive records from a large highly technified dairy farm were used; the variables evaluated were temperature humidity index (THI; <77, 77-83, >83) at calving and AFC (<2.0, 2.0-2.2 and >2.2 years). Across age groups, the cases of dystocic parturition increased (p<0.05) when the deliveries occurred with severe heat stress (4.3% vs. 3.3% for THI >83 and <83 units, respectively). Across THI, conception rate at the first postpartum artificial insemination (AI) was lower (p=0.02) for heifers calving for the first time >2.2 years compared to heifers calving between 2.0 and 2.2 and <2.0 years (9.8, 15.3 and 13.7%, respectively). Conception rate at first AI postcalving was higher (p<0.01) in heifers calving with THI less than 83 units than in heifers calving with a THI >83 units (16.8 vs. 5.4%). The conception rate considering all services was affected (p<0.05) by AFC (42.7, 50.4 and 40.9% for AFC <2.0, 2.0-2.2 and >2.2 years, respectively). The interaction AFC × THI at calving was significant (p<0.05). The occurrence of metritis was higher (p<0.05) in heifers <2.0 years of age at calving than those calving after 2 years of age. The presence of ovarian cysts was less common (p<0.05) in heifers with greater AFC. In conclusion, increasing the AFC in Holstein heifers had no benefits in reproduction and health, compared with heifers calving at <2.0 years. These data in a hot climate suggest that heifers should be selected to begin their first lactation before 2 years of age
Whole-grain cereal voluntary intake and preference in Japanese quail (Coturnix coturnix japonica)
No full textJapanese quail (Coturnix coturnix japonica) usually fed on ground or pelleted balanced feeds, while whole grains are supplied in alternative systems. Voluntary intake and preference of four whole-grain cereals (durum wheat, bread wheat, triticale and barley) were assessed in Japanese quails. Two experiments were performed: (i) a trial with five batches of six randomly selected quails (three males, three females) allocated to each treatment consisting of one cereal or a balanced feed (control) in the voluntary intake experiment; and (ii) a trial with four bird batches receiving simultaneously the four cereals in the preference experiment. Three repetitions of each trial were performed. When feedstuffs were provided as a sole feed, voluntary feed intake differed, being the highest in quails fed the balanced feed (20.0 g/d), intermediate for durum wheat (15.0 g/d), bread wheat (15.8 g/d) or triticale (15.6 g/d), and the lowest for barley (12.1 g/d). Voluntary intake did not differ between sexes. Positive correlations existed between voluntary feed intake and live weight of quails, being the highest and very strong for the balanced feed, moderate for durum and bread wheat and barley, and weak for triticale. The preference trial showed that quails preferred durum wheat (7.1 g/d), triticale (4.0 g/d), bread wheat (3.0 g/d) and barley (0.3 g/d) in descending order, independently of sex. Positive correlations existed between daily feed intake and live weight of birds for durum and bread wheat. Strong positive correlation existed between bird live weight and total intake when the four cereals were available simultaneously. Differences in voluntary intake and preference among whole-grain cereals should be take into account when used to feed quails
Proteomic changes in the grains of foxtail millet (Setaria italica (L.) Beau) under drought stress
No full textDrought has become a serious problem that threatens global food security. Foxtail millet (Setaria italica) can be used as a model crop for drought-resistant research because of its excellent performance in drought tolerance. In this study, the typical drought-tolerant foxtail millet landrace ‘Huangjinmiao’ was grown in a field under control and drought stress conditions to investigate its response to drought stress. The proteins in the harvested grains were analysed through two-dimensional electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization-tandem time-of-flight (MALDI-TOF/TOF) analysis to characterize the response of foxtail millet under drought stress at a proteomic level. A total of 104 differentially abundant protein spots (DAPs) were identified; among them, 57 were up-regulated and 47 were down-regulated under drought treatment. The identified proteins were involved in an extensive range of biological processes, including storage proteins, protein folding, starch and sucrose metabolism, glycolysis/gluconeogenesis, biosynthesis of amino acids, detoxification and defense, protein degradation, tricarboxylic acid (TCA) cycle, protein synthesis, energy metabolism, transporter, pentose phosphate pathway, and signal transduction. Post-translational protein modifications might also occur. Moreover, the albumin content greatly decreased under drought stress, whereas the gliadin content considerably increased (p<0.01). In conclusion, this study provides new information on the proteomic changes in foxtail millet under drought stress and a framework for further studies on the function of these identified proteins
Water-bath stunning process in broiler chickens: Effects of voltage and intensity
No full textThe effect of electrical parameters (intensity and voltage) to obtain an effective water-bath stunning in a commercial poultry slaughterhouse was studied. A total of 390 broilers were randomly divided into six experimental groups according to the intensity (150 and 200 mA) and voltage (51-60, 61-80 and 81-100 V). Statistical analysis showed a significant (p<0.001) effect of electrical parameters on the cloacal reflex since the response rate was 8 s for 96% of broilers. On the other hand, the stunning treatments suppressed the palpebral reflex up to 12 s in 80% of broilers. All stun-treated broilers showed breathing response after 27 s with an average time between 45 and 50 s depending on voltage and intensity of the current. Regarding voltage, the percentage of complete neck cutting increased with the increase of voltage, presenting the highest levels in broilers stunned at 81-100 V (100 and 92.8%, for 150 and 200 mA, respectively). Concerning to intensity, the best results were obtained in broilers stunned at 150 mA, showing mean percentages of 94.83 and 87.30%, for 150 and 200 mA, respectively. The bruises on wings were significantly (p<0.001) affected by voltage, observing the highest values in broilers slaughtered at lower voltages. An opposite trend was observed on bruises under the wings since the lowest voltages showed (p<0.001) lower levels (1.34 and 1.42%, for 150 and 200 mA, respectively). Finally, bruises on dorsal winds and on back were significantly (p<0.001) influenced by intensity level, showing the lowest percentages in broilers stunned at 150 mA