Spanish Journal of Agricultural Research
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Hematological parameters, liver integrity and growth of Nile tilapia fingerlings fed diets supplemented with propolis extract
No full textAim of study: To assess the effects of propolis extract supplementation in diets for Nile tilapia (Oreochromis niloticus) fingerlings on growth performance, hematological and histological parameters.
Area of study: The study was carried out in Paraná (Brazil).
Material and methods: The experimental design was based on six treatments including the control diet and propolis supplementation (2%, 4%, 6%, 8% and 10% in the diet). Three hundred Nile tilapia fingerlings, with an initial weight of 0.61± 0.02 g, were distributed in 30 plastic mesh hapas (0.15 m3 each) arranged in a concrete tank of 25 m3 of water volume. The duration of the experimental period was 90 days.
Main results: The increasing levels of propolis did not influence the growth performance and proximate composition of fishes. Red blood cells and hematological indices were not affected by propolis supplementation. However, total leukocytes and thrombocytes were higher in fish fed on propolis diets, being significant in fish fed 2% and 8%, and 6% and 8% supplemented diets groups, respectively.
Research highlights: The supplementation of propolis alcoholic extract in the range of 2, 4, 6 and 8% in the diet for Nile tilapia fingerlings promote healthier fish with increased immunity in the evaluated culture conditions
A two-step feeding of calcium salts of fish oil improves reproductive performance in Holstein cows
No full textAim of study: To examine the effects of a biphasic schedule of feeding n-3 fatty acids on dairy cows.Area of the study: Isfahan, Iran.Materials and methods: 140 lactating Holstein cows were allotted at calving into two groups of 70 animals and received one of two dietary treatments: 1) saturated fatty acids (SFA, containing 80% palmitic acid) or 2) calcium salt of fish oil (CSFO, containing 16% eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)), with an n-6/n-3 FA ratio of approximately 7 for SFA and 5 for CSFO treatments. The dietary supplements were fed to the respective groups at 240 g/head.day from 0 to 21 days in milk, and 120 g/head.day from 22 to 150 days in milk. Milk yield was recorded biweekly and milk composition was evaluated monthly. The concentration of FA in the milk and blood was determined on d-90 of the experiment in 10 cows randomly selected from each group. Reproductive indices were recorded until d-150.Main results: The CSFO supplementation did not affect average milk yield, milk composition or milk somatic cell count (SCC); however, in some weeks it decreased milk SCC (p<0.05). Plasma concentrations of palmitic acid and n-3 FA as well as milk fat concentration of EPA and DHA increased in the CSFO-fed cows (p<0.05). Feeding the CSFO decreased open days (100 vs 119 days, p<0.05), service per conception and all service conception rates (p<0.05).Research highlights: The implementation of a two-stage feeding program of n-3 FA improved reproductive variables and reduced milk SCC in dairy cows
Uncertainty analysis of the HORTSYST model applied to fertigated tomatoes cultivated in a hydroponic greenhouse system
No full textAim of study: The objective was to perform an uncertainty analysis (UA) of the dynamic HORTSYST model applied to greenhouse grown hydroponic tomato crop. A frequentist method based on Monte Carlo simulation and the Generalized Likelihood Uncertainty Estimation (GLUE) procedure were used.Area of study: Two tomato cultivation experiments were carried out, during autumn-winter and spring-summer crop seasons, in a research greenhouse located at University of Chapingo, Chapingo, Mexico.Material and methods: The uncertainties of the HORTSYST model predictions PTI, LAI, DMP, ETc, Nup, Pup, Kup, Caup, and Mgup uptake, were calculated, by specifying the uncertainty of model parameters 10% and 20% around their nominal values. Uniform PDFs were specified for all model parameters and LHS sampling was applied. The Monte Carlo and the GLUE methods used 10,000 and 2,000 simulations, respectively. The frequentist method included the statistical measures: minimum, maximum, average values, CV, skewness, and kurtosis whilst GLUE used CI, RMSE, and scatter plots.Main results: As parameters were changed 10%, the CV, for all outputs, were lower than 15%. The smallest values were for LAI (10.75%) and DMP (11.14%) and the largest was for ETc (14.47%). For Caup (12.15%) and Pup (12.27%), the CV was lower than the one for Nup and Kup. Kurtosis and skewness values were close as expected for a normal distribution. According to GLUE, crop density was found to be the most relevant parameter given that it yielded the lowest RMSE value between the simulated and measured values.Research highlights: Acceptable fitting of HORTSYST was achieved since its predictions were inside 95% CI with the GLUE procedure
Collaboration for social innovation in the agri-food system in Latin America and the Caribbean
No full textAim of study: This study reviews the state of the art of collaboration for social innovation in food and rural systems. The analysis focuses on cooperation by farms and agro-industry companies. The purpose is to identify not only the state of the art of this research topic but also the main authors, the countries where these studies are conducted and the dynamics of research networks in relation to these topics.
Area of study: Latin America and the Caribbean (LAC).
Material and methods: The Web of Science database was used to search for articles containing the terms ‘cooperation’, ‘networks’, ‘innovation’, ‘social’, ‘rural’ and ‘LAC’. Using VOSviewer network creation and analysis software, maps of citations, co-authorship, co-citations and co-occurrence of key-words were created and analysed. Content analysis was then performed. Finally, the research areas that the authors of the analysed articles consider to be of interest for future research were identified.
Main results: The results reveal that researchers from Latin America and other regions, especially Europe and the English-speaking world, are showing a growing interest in collaborative systems for development and social innovation in LAC.
Research highlights: The analysis enables further progress to be made in identifying the main drivers of collaboration in the LAC rural sector. These main drivers include social innovation, knowledge, sustainable management and social capital
Comparative performance analysis of innovative separation chamber configurations: Numerical and experimental investigations
No full textAim of study: Novel configurations of separation chamber are proposed to resolve the critical issue of separation in agro-industrial equipment.Area of study: Dept. of Mechanical and Biosystems Engineering, Urmia, IranMaterial and methods: Precise and instrumented experimentation has been conducted to calibrate the computational fluid dynamics (CFD) methodology in the modeling and simulating chickpea pod separation. Mechanisms were selected based on optimizing separation efficiency, relative purification and required airflow as a criterion for energy consumption.Main results: Applying a guiding blade and suction fans may potentially increase the separation efficiency while reducing the relative purification and required airflow. The highest separation efficiency (95%), the lowest required airflow (545 m³/h) and the lowest pressure drop (16.3 Pa), were obtained by such configuration. Furthermore, the highest relative purification of 90% was achieved when the mechanism was free of blade and fans.Research highlights: To integrate the advantages of the above-mentioned configurations, a series-type assembling them is proposed to preserve the separation efficiency and relative purification at the highest level, meanwhile reducing the required airflow. Also, 15% enhancement in the separation efficiency and 302.8 m³/h reductions in the airflow were found as a crucial finding. The high correlation of experimental and theoretical CFD results is the key point to motivate the researchers for extension of similar case projects
Soil organic carbon accumulation and carbon dioxide emissions during a 6-year study in irrigated continuous maize under two tillage systems in semiarid Mediterranean conditions
No full textAim of study: To evaluate the effects of conventional tillage (CT) and no tillage (NT) systems on the soil organic carbon (SOC) changes, CO2 emissions and their relation with soil temperature and grain yield in a monoculture of irrigated maize during six years.Area of study: In Zamadueñas experimental field in the Spanish province of Valladolid, from 2011 to 2017.Material and methods: The SOC content was determined by collecting soil samples up to 30 cm in November at two years interval. Short-term CO2 emissions were measured simultaneously with soil temperature using a respiration chamber and a hand-held probe immediately before, after every tillage operation and during the maize cycle.Main results: The SOC stock of the top 30 cm soil layers was 13% greater under NT than CT. Short-term CO2 emissions were significantly higher under CT ranging from 0.8 to 3.4 g CO2 m-2 h-1 immediately after tillage while under NT system, soil CO2 fluxes were low and stable during this study period. During the first 48 h following tillage, cumulative CO2 emissions ranged from 0.6 to 2.4 Mg CO2 ha-1 and from 0.2 to 0.3 Mg CO2 ha-1 under CT and NT systems, respectively. Soil temperature did not show significant correlation with CO2 emissions; however, it depended mostly on the time of measurement.Research highlights: No tillage increased the SOC accumulation in the topsoil layer, reduced CO2 emissions without decreasing maize grain yield and minimized the impact on climate change compared to CT system
Production efficiency of different crop rotations and tillage systems
No full textAim of study: The production efficiency of crop rotations was evaluated based on the yield of the main crop (cereal grains and pea seeds) and yield of the by-product (straw) converted per cereal units (CU), and on total protein yield.
Area of study: South-eastern Poland, Europe (2017-2019).
Material and methods: The first order experimental factor included crop rotations: A): peas–durum wheat–spring barley; B): spring wheat–durum wheat–spring barley +oats; and C): spring barley–durum wheat–spring wheat. The second order experimental factor included tillage systems: CT, conventional tillage, RT, reduced tillage, and NT, no-tillage.
Main results: The yield of pea seeds, cereal grains, and straw per CU was higher in crop rotation A than B (127.8 CU vs. 101.1 CU). Higher CU yields were also recorded in crop rotation C than B (by 18.9 CU). The tillage system had no effect on CU yield. The total protein yield was significantly higher in crop rotation A (2110.7 kg ha-1) than in crop rotations B (by 808.8 kg ha-1) and C (by 448.0 kg ha-1). A higher protein yield was also recorded in RT than in the NT system.
Research highlights: The units used for CR assessment, i.e. CU and total protein yield, enable to reliably evaluate the production yield of both CRs and tillage systems
Short communication: Sublethal effects of insecticides used in strawberry on Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)
No full textAim of study: Assessment of toxicity and sublethal effects of registered insecticides currently used in strawberry cultivation in Brazil on Trichogramma pretiosum Riley adults.Area of study: The study was conducted under laboratory conditions in Paraná (Brazil).Material and methods: Previously non-parasitized Duponchelia fovealis Zeller (Lepidoptera: Cambridae) eggs were dipped into insecticide dilutions or control solution. Seven active ingredients were tested: thiamethoxam, abamectin, azadirachtin, spinetoram, chlorfenapyr, lambda-cyhalothrin and chlorpyriphos. Side-effects of pesticides were quantified by measuring mortality on T. pretiosum females in 24 h, longevity after exposure to the insecticides, parasitism and emergence rates, and offspring sex ratio. These traits were also measured on the second generation.Main results: According to IOBC criteria, thiamethoxam was classified as harmless; abamectin, chlorfenapyr and spinetoram as slightly toxic; azadirachtin and lambda-cyhalothrin as moderately toxic and chlorpyriphos as toxic. The emergence rate of T. pretiosum secondgeneration was not significantly affected by thiamethoxam, abamectin, azadirachtin, and chlorfenapyr. Sublethal effects caused by azadirachtin, abamectin and chlorfenapyr were verified in the secondgeneration.Research highlights: The information generated by this study is useful for designing future biological control strategies in integrated pest management programs against D. fovealis
Antimicrobial, immunomodulatory and hepatomodulatory effects of aqueous extracts of Petiveria alliacea root and leaf on growing pullets
No full textAim of study: To evaluate antimicrobial, immunomodulatory and hepatomodulatory effects of aqueous extracts of Petiveria alliacea L. (Guinea hen weed) root and leaf on growing pullets.Area of study: Abeokuta, Nigeria.Material and methods: Two hundred and eighty eight eight-weeks-old Isa-brown pullets were divided into eight treatments which consisted in birds administered root extracts or leaf extracts at four different concentrations (0, 15, 30 and 45 ɡ/L). Each treatment was replicated three times with 12 pullets per replicate.Main results: Oocyst counts was lower (p<0.05) in pullets administered root extract (78.42 opɡ) compared with leaf extract (103.58 opɡ). Oocyst counts was lower (p<0.05) in pullets administered 30 and 45 ɡ/L root or leaf extract compared with other treatments. Bacteria counts reduced (p<0.05) in pullets administered root extract compared with leaf extract. Pullets administered 45 ɡ/L root extract recorded lowest (p<0.05) bacteria count. Bursa and thymus weights increased in pullets administered root or leaf extract compared with the control. Pullets administered 30 and 45 ɡ/L root or leaf extract had highest (p<0.05) antibody titre against Newcastle disease vaccine 8.80, 8.86, 8.74 and 8.80 (log2) respectively. There was fatty infiltration in liver of control birds, while hepatocytes appeared normal in liver of pullets administered P. alliacea extracts.Research highlights: P. alliacea root and leaf extracts at 45 ɡ/L performed best as antimicrobial, immune-stimulating and hepato-protective agent in pullets. This study highlights P. allicaea as a valuable antimicrobial and immunostimulating agent in poultry production