Revista de la Facultad de Ciencias Agrarias
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Growth and Foliar Alkaloid Content of Clitoria ternatea under Different Irrigation Frequencies
Full text linkClitoria ternatea is widely used in tropical livestock farming. This study evaluates the agronomic performance and alkaloid content of C. ternatea under different irrigation frequencies in protected cultivation. A randomized block design with controlled manual irrigation was implemented with five treatments, four replicates, and five experimental units per treatment. Treatments included daily irrigation (T0), irrigation every two days (T1), every three days (T2), every four days (T3), and every five days (T4). We evaluated plant height, leaf and internode number, leaf area, green and dry matter yield, and alkaloid content. Irrigation every three or four days generally resulted in the highest values for the measured variables compared to the control. Reduced irrigation frequency affects the agronomic performance of C. ternatea in protected cultivation. Agronomic indicators were highest under irrigation every three or four days. Alkaloid content did not vary with irrigation frequency.
Highlights:
Clitoria ternateais widely used in tropical livestock farming due to its adaptability, productivity, and nutritional value.
Thestructured design with controlled manual irrigation had five treatments, four replicates and five experimental units, totalizing 100 plants.
Maximum plant height was achieved when Clitoria ternateareceived irrigation every four or five days, with T4 reaching 48.50 cm at 50 days
Leaf number increased as plants matured, with the highest value recorded in T3 (48 leaves at 50 days).
Irrigation every 2 days increases alkaloid content and plant yield.Clitoria ternatea is widely used in tropical livestock farming. This study evaluates the agronomic performance and alkaloid content of C. ternatea under different irrigation frequencies in protected cultivation. A randomized block design with controlled manual irrigation was implemented with five treatments, four replicates, and five experimental units per treatment. Treatments included daily irrigation (T0), irrigation every two days (T1), every three days (T2), every four days (T3), and every five days (T4). We evaluated plant height, leaf and internode number, leaf area, green and dry matter yield, and alkaloid content. Irrigation every three or four days generally resulted in the highest values for the measured variables compared to the control. Reduced irrigation frequency affects the agronomic performance of C. ternatea in protected cultivation. Agronomic indicators were highest under irrigation every three or four days. Alkaloid content did not vary with irrigation frequency.
Highlights:
Clitoria ternateais widely used in tropical livestock farming due to its adaptability, productivity, and nutritional value.
Thestructured design with controlled manual irrigation had five treatments, four replicates and five experimental units, totalizing 100 plants.
Maximum plant height was achieved when Clitoria ternateareceived irrigation every four or five days, with T4 reaching 48.50 cm at 50 days
Leaf number increased as plants matured, with the highest value recorded in T3 (48 leaves at 50 days).
Irrigation every 2 days increases alkaloid content and plant yield
Isolation of Polyhydroxyalkanoate (PHA)-Producing Azotobacter spp. from Crop Rhizospheres Located in Lima, Peru
Full text linkPHAs are polyesters found as internal granules in several microorganisms. Azotobacter is known for its ability to produce PHA. This study aimed to isolate Azotobacter from the rhizosphere of selected crops located in Lima and evaluate their PHA-producing potential. Nile Red medium was used for PHA detection, and Sudan Black B staining allowed microscopic observation. Biopolymer production and quantification were carried out in Burk’s medium, PHA minimal medium (PHAMM), and modified PHAMM. In Nile Red medium, 68.2% of strains produced PHA, with Azotobacter AzoLur20 exhibiting the highest production, 2.1 g/L of PHA at 96 hours in PHAMM. However, strain AzoLur19 showed higher productivity and stability, achieving 0.06 g/L*h of PHA. Additionally, Sudan Black B staining in Burk’s medium revealed larger Azotobacter cells with more defined granules. AzoLur19 was classified as Azotobacter chroococcum. In conclusion, Azotobacter species isolated from crops located in Lima can produce PHA with high yields, with A. chroococcum as the predominant species.
Highlights:
A total of 22 Azotobacter strains were isolated, with A. chroococcum AzoLur19 identified as a promising PHA producer.
PHA accumulation was successfully screened using Nile Red and Sudan Black B staining methods.
AzoLur20 and AzoLur23 achieved high PHA yields, with up to 87.67% accumulation in Burk medium.
AzoLur19 strain reached the highest productivity (0.06 g/L·h) in both PHAMM and modified PHAMM media.
Modified PHAMM medium showed potential as an alternative for efficient PHA biosynthesis.PHAs are polyesters found as internal granules in several microorganisms. Azotobacter is known for its ability to produce PHA. This study aimed to isolate Azotobacter from the rhizosphere of selected crops located in Lima and evaluate their PHA-producing potential. Nile Red medium was used for PHA detection, and Sudan Black B staining allowed microscopic observation. Biopolymer production and quantification were carried out in Burk’s medium, PHA minimal medium (PHAMM), and modified PHAMM. In Nile Red medium, 68.2% of strains produced PHA, with Azotobacter AzoLur20 exhibiting the highest production, 2.1 g/L of PHA at 96 hours in PHAMM. However, strain AzoLur19 showed higher productivity and stability, achieving 0.06 g/L*h of PHA. Additionally, Sudan Black B staining in Burk’s medium revealed larger Azotobacter cells with more defined granules. AzoLur19 was classified as Azotobacter chroococcum. In conclusion, Azotobacter species isolated from crops located in Lima can produce PHA with high yields, with A. chroococcum as the predominant species.
Highlights:
A total of 22 Azotobacter strains were isolated, with A. chroococcum AzoLur19 identified as a promising PHA producer.
PHA accumulation was successfully screened using Nile Red and Sudan Black B staining methods.
AzoLur20 and AzoLur23 achieved high PHA yields, with up to 87.67% accumulation in Burk medium.
AzoLur19 strain reached the highest productivity (0.06 g/L·h) in both PHAMM and modified PHAMM media.
Modified PHAMM medium showed potential as an alternative for efficient PHA biosynthesis
Critical Point Analysis for Sustainable Management of Cydia pomonella (Lepidoptera: Tortricidae) in Smallholder Walnut Farms of Catamarca, Argentina
Full text linkIn Argentina, 80% of walnut production is carried out by smallholder farms facing poor technology, production constraints, and substantial economic losses due to pests like Cydia pomonella (codling moth). We assessed sustainability risks linked to phytosanitary management on small farms in the Ambato region of Catamarca, Argentina. Our analysis included a “strong sustainability” framework with three key dimensions: ecological, economic, and sociocultural. A total of 26 indicators were related to this species’ management. Using semi-structured interviews, visual aids, and field surveys across seven farms, an overall sustainability index of 1.521 was calculated, with 50% of the indicators scoring below the established threshold (on a five-level sustainability scale, the selected threshold was level two). The ecological dimension emerged as the most sustainable. Limitations included absent systematic monitoring and optimisation of treatment timing, solely with agrochemical control, weak farmer-to-farmer collaboration, and insufficient training opportunities. Cluster analysis revealed four distinct groups based on phytosanitary practices. This study highlights critical intervention points and suggests agroecological strategies to enhance sustainable pest management in smallholder walnut systems.
Highlights:
A strong sustainability framework (ecological, sociocultural and economic) was applied to assess Cydia pomonellamanagement in smallholder walnut farms in Catamarca, Argentina.
Sustainability was evaluated through 26 indicators using semi-structured interviews, visual tools, and field surveys.
The overall sustainability index was low (1.521), with 50% of indicators falling below the acceptable threshold.
Ecological practices showed comparatively higher sustainability, but suffered from lack of monitoring and weak communication between farmers.
Cluster analysis indicated four distinct phytosanitary management profiles, suggesting targeted agroecological interventions.In Argentina, 80% of walnut production is carried out by smallholder farms facing poor technology, production constraints, and substantial economic losses due to pests like Cydia pomonella (codling moth). We assessed sustainability risks linked to phytosanitary management on small farms in the Ambato region of Catamarca, Argentina. Our analysis included a “strong sustainability” framework with three key dimensions: ecological, economic, and sociocultural. A total of 26 indicators were related to this species’ management. Using semi-structured interviews, visual aids, and field surveys across seven farms, an overall sustainability index of 1.521 was calculated, with 50% of the indicators scoring below the established threshold (on a five-level sustainability scale, the selected threshold was level two). The ecological dimension emerged as the most sustainable. Limitations included absent systematic monitoring and optimisation of treatment timing, solely with agrochemical control, weak farmer-to-farmer collaboration, and insufficient training opportunities. Cluster analysis revealed four distinct groups based on phytosanitary practices. This study highlights critical intervention points and suggests agroecological strategies to enhance sustainable pest management in smallholder walnut systems.
Highlights:
A strong sustainability framework (ecological, sociocultural and economic) was applied to assess Cydia pomonellamanagement in smallholder walnut farms in Catamarca, Argentina.
Sustainability was evaluated through 26 indicators using semi-structured interviews, visual tools, and field surveys.
The overall sustainability index was low (1.521), with 50% of indicators falling below the acceptable threshold.
Ecological practices showed comparatively higher sustainability, but suffered from lack of monitoring and weak communication between farmers.
Cluster analysis indicated four distinct phytosanitary management profiles, suggesting targeted agroecological interventions
First Report of the Black Soybean Weevil Rhyssomatus subtilis Fiedler (Coleoptera: Curculionidae) in Córdoba, Argentina. Crop Damage Estimation
Full text linkThe black soybean weevil is an endemic pest in northwestern and northeastern Argentina, causing significant damage. The objective of this study was to confirm the presence of this species in Córdoba, describe symptomatology and evaluate the potential impact on the crop. Surveys were conducted in plots located in the north-central part of the province. Individuals were collected and a quantitative assessment of symptoms and damage was conducted. Twenty compound samples were taken from sectors showing different physiological appearances (green vs. yellowish). In each group, total pod number and damaged pod number allowed calculating damage percentage. Data were analyzed by ANOVA and Fisher's test (α = 0.05). All collected individuals matched the morphological descriptions reported in the literature for the species Rhyssomatus subtilis Fiedler. Green plants had a higher proportion of damaged pods (0.89) and fewer pods (31.85) compared to yellowish plants (0.53 and 46.65, respectively). This relationship suggests a direct effect on biomass partitioning. Our finding remaps the pest’s distribution range, warning areas of high agricultural production in Córdoba and raising the need to link public-private actions to minimize its spread.
Highlights:
First record of Rhyssomatus subtilis in soybean fields in Córdoba Province, Argentina. The black soybean weevil was detected in five sites in the central-northern region, where no previous records existed.
Detection was triggered by reports of pod damage. Identification was based on characteristic injury and the collection of larvae and adults, confirmed with expert input and literature.
Damage assessment revealed physiological differences in affected plants. Severely damaged plants showed delayed senescence and symptoms consistent with green stem disorder.
Pod injury by subtilis significantly reduced pod set. Statistical analysis showed marked differences in the number of pods between high- and low-damage areas.The black soybean weevil is an endemic pest in northwestern and northeastern Argentina, causing significant damage. The objective of this study was to confirm the presence of this species in Córdoba, describe symptomatology and evaluate the potential impact on the crop. Surveys were conducted in plots located in the north-central part of the province. Individuals were collected and a quantitative assessment of symptoms and damage was conducted. Twenty compound samples were taken from sectors showing different physiological appearances (green vs. yellowish). In each group, total pod number and damaged pod number allowed calculating damage percentage. Data were analyzed by ANOVA and Fisher's test (α = 0.05). All collected individuals matched the morphological descriptions reported in the literature for the species Rhyssomatus subtilis Fiedler. Green plants had a higher proportion of damaged pods (0.89) and fewer pods (31.85) compared to yellowish plants (0.53 and 46.65, respectively). This relationship suggests a direct effect on biomass partitioning. Our finding remaps the pest’s distribution range, warning areas of high agricultural production in Córdoba and raising the need to link public-private actions to minimize its spread.
Highlights:
First record of Rhyssomatus subtilis in soybean fields in Córdoba Province, Argentina. The black soybean weevil was detected in five sites in the central-northern region, where no previous records existed.
Detection was triggered by reports of pod damage. Identification was based on characteristic injury and the collection of larvae and adults, confirmed with expert input and literature.
Damage assessment revealed physiological differences in affected plants. Severely damaged plants showed delayed senescence and symptoms consistent with green stem disorder.
Pod injury by subtilis significantly reduced pod set. Statistical analysis showed marked differences in the number of pods between high- and low-damage areas
Valorization of regional crude glycerol. Culture media optimization for batch docosahexaenoic acid (DHA) production with Aurantiochytrium sp.
Full text linkDocosahexaenoic acid (DHA) has many benefits for human health. Commercial DHA sources derive from marine fish but present several production challenges. Aurantiochytrium sp., an abundant marine microalga, becomes an alternative for DHA production. Crude glycerol produced by small-scale biodiesel refineries is a regional, available, and inexpensive waste that can be converted into value-added compounds. This study investigated crude glycerol as a potential carbon source for DHA-rich oil production using an aerobically isolated Aurantiochytrium sp. in batch shake flasks. We also optimized the culture medium formulation by varying carbon and nitrogen sources, thereby reducing medium costs while maximizing DHA production. A larger initial Aurantiochytrium sp. inoculum improved cell concentration and medium carbon depletion, increasing DHA productivity (PDHA). Increasing culture time showed no differences in Aurantiochytrium sp. growth parameters, but reduced DHA production. The absence of yeast extract in the culture media resulted in faster substrate metabolism by Aurantiochytrium sp. and increased DHA production. Crude glycerol yielded the highest PDHA (15.35 mg L-1 h-1) at 120 h. Crude glycerol can be used as a cheaper carbon source in media formulation with Aurantiochytrium sp. cultures for DHA production.
Highlights:
Crude glycerol is a cheap and highly available carbon source used by Aurantiochytrium for ω-3 DHA-rich oil production.
Absent yeast extract in culture media enabled faster glucose metabolism, favoring lipid production and improving CTFA and CDHA.
The largest initial inoculum (10.0% v/v) of Aurantiochytrium improved DCW, substrate depletion and PDHA.
BCG medium yielded the highest CDHA and PDHA (84 g L-1 and 15.35 mg L-1 h-1, respectively) at 120 h.
Quality assays of ω-3 DHA-rich oil product showed it is safer for human and animal food formulation.Docosahexaenoic acid (DHA) has many benefits for human health. Commercial DHA sources derive from marine fish but present several production challenges. Aurantiochytrium sp., an abundant marine microalga, becomes an alternative for DHA production. Crude glycerol produced by small-scale biodiesel refineries is a regional, available, and inexpensive waste that can be converted into value-added compounds. This study investigated crude glycerol as a potential carbon source for DHA-rich oil production using an aerobically isolated Aurantiochytrium sp. in batch shake flasks. We also optimized the culture medium formulation by varying carbon and nitrogen sources, thereby reducing medium costs while maximizing DHA production. A larger initial Aurantiochytrium sp. inoculum improved cell concentration and medium carbon depletion, increasing DHA productivity (PDHA). Increasing culture time showed no differences in Aurantiochytrium sp. growth parameters, but reduced DHA production. The absence of yeast extract in the culture media resulted in faster substrate metabolism by Aurantiochytrium sp. and increased DHA production. Crude glycerol yielded the highest PDHA (15.35 mg L-1 h-1) at 120 h. Crude glycerol can be used as a cheaper carbon source in media formulation with Aurantiochytrium sp. cultures for DHA production.
Highlights:
Crude glycerol is a cheap and highly available carbon source used by Aurantiochytrium for ω-3 DHA-rich oil production.
Absent yeast extract in culture media enabled faster glucose metabolism, favoring lipid production and improving CTFA and CDHA.
The largest initial inoculum (10.0% v/v) of Aurantiochytrium improved DCW, substrate depletion and PDHA.
BCG medium yielded the highest CDHA and PDHA (84 g L-1 and 15.35 mg L-1 h-1, respectively) at 120 h.
Quality assays of ω-3 DHA-rich oil product showed it is safer for human and animal food formulation
Preventive and curative effects of native yeasts on different Botrytis cinerea strains in “Superior Seedless” (Vitis vinifera L.) table grape cultured in Argentina
Full text linkThe fermenting grape must is a dynamic, stressful, and selective habitat where many yeast species compete. Specific yeasts isolated from this habitat can play a fundamental role in table grape biocontrol of fungal diseases. The present study evaluated 225 grapevine yeasts against four Botrytis cinerea strains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms. Eighteen enological yeasts (13 Saccharomyces and 5 non- Saccharomyces) showed preventive antifungal activity against the four native B. cinerea strains, with disease severity varying between 0 and 49.91%. These 18 strains also presented curative activity against at least one of the B. cinerea strains assayed (severity values between 0 and 45.99%). Considering action mechanisms, thirteen yeast strains inhibited mycelial growth of at least one B. cinerea strain during dual plating (antibiosis), “killer” activity, and volatile antifungal assays. Our results showed that 7 yeast strains affected conidial germination (CG) and germinal tube length (GTL) of at least one B. cinerea isolate. Two yeast strains occupied the same niche as 4 B. cinerea strains (NOI values > 0.90). All yeast strains exhibited at least two inhibitory action mechanisms against gray rot, except for BSc140 with one mechanism. The possibility of more than one mechanism per yeast strain makes biocontrol an effective tool to prevent and cure gray rot in table grapes.
Highlights:
We evaluated 225 native grapevine yeasts against four Botrytis cinereastrains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms.
Saccharomyces (13) and 5 non- Saccharomyces(5) strains showed preventive antifungal activity against native cinerea strains (4).
Some grapevine yeasts (10 Saccharomycesy 4 non- Saccharomyces) presented curative activity against cinerea strains.
Grapevine yeasts, with preventive and curative activity, presented different antifungal mechanisms against cinerea.
The fermenting grape must is a dynamic, stressful, and selective habitat where many yeast species compete. Specific yeasts isolated from this habitat can play a fundamental role in table grape biocontrol of fungal diseases. The present study evaluated 225 grapevine yeasts against four Botrytis cinerea strains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms. Eighteen enological yeasts (13 Saccharomyces and 5 non- Saccharomyces) showed preventive antifungal activity against the four native B. cinerea strains, with disease severity varying between 0 and 49.91%. These 18 strains also presented curative activity against at least one of the B. cinerea strains assayed (severity values between 0 and 45.99%). Considering action mechanisms, thirteen yeast strains inhibited mycelial growth of at least one B. cinerea strain during dual plating (antibiosis), “killer” activity, and volatile antifungal assays. Our results showed that 7 yeast strains affected conidial germination (CG) and germinal tube length (GTL) of at least one B. cinerea isolate. Two yeast strains occupied the same niche as 4 B. cinerea strains (NOI values > 0.90). All yeast strains exhibited at least two inhibitory action mechanisms against gray rot, except for BSc140 with one mechanism. The possibility of more than one mechanism per yeast strain makes biocontrol an effective tool to prevent and cure gray rot in table grapes.
Highlights:
We evaluated 225 native grapevine yeasts against four Botrytis cinereastrains isolated from “Superior Seedless” grapes, considering the possible antifungal action mechanisms.
Saccharomyces (13) and 5 non- Saccharomyces(5) strains showed preventive antifungal activity against native cinerea strains (4).
Some grapevine yeasts (10 Saccharomycesy 4 non- Saccharomyces) presented curative activity against cinerea strains.
Grapevine yeasts, with preventive and curative activity, presented different antifungal mechanisms against cinerea.
Obtaining a lipid extract from peach palm (Bactris gasipaes Kunth) epicarp. Quantification of carotenoid content and application as a food additive
Full text linkThe agro-industrial assessment of fruit by-products as food additives would allow compliance with Sustainable Development Goals. This research aimed at the homogenizer-assisted extraction of total carotenoids from peach palm (Bactris gasipaes) peel (epicarp) with sunflower oil. We also studied its application as a natural additive in white corn flour food. The response surface methodology and the rotational composite central design quantified the extraction process. The studied factors were extraction speed, temperature, time, and liquid-solid ratio. Total carotenoid content in the extract (336.06 µg/g dried epicarp) was optimized at 50°C, with 76 seconds, extraction speed of 19200 rpm, and liquid-solid ratio of 48.75 mL/g. The green extract obtained from homogenizer-assisted extraction constitutes a natural additive with agro-industrial potential for use in roasted corn cake, increasing carotenoid (30.60 µg/g of β-carotene), provitamin A (4.14 µg/g) and antioxidant activity (11.57 % DPPH).
Highlights:
Homogenizer-assisted extraction (HAE) is adequate for carotenoid extraction in peach palm epicarp.
The lipid extract from the peach palm epicarp is a source of provitamin A.
Lipid extract obtained is a natural additive with potential for use in corn griddle cakes.The agro-industrial assessment of fruit by-products as food additives would allow compliance with Sustainable Development Goals. This research aimed at the homogenizer-assisted extraction of total carotenoids from peach palm (Bactris gasipaes) peel (epicarp) with sunflower oil. We also studied its application as a natural additive in white corn flour food. The response surface methodology and the rotational composite central design quantified the extraction process. The studied factors were extraction speed, temperature, time, and liquid-solid ratio. Total carotenoid content in the extract (336.06 µg/g dried epicarp) was optimized at 50°C, with 76 seconds, extraction speed of 19200 rpm, and liquid-solid ratio of 48.75 mL/g. The green extract obtained from homogenizer-assisted extraction constitutes a natural additive with agro-industrial potential for use in roasted corn cake, increasing carotenoid (30.60 µg/g of β-carotene), provitamin A (4.14 µg/g) and antioxidant activity (11.57 % DPPH).
Highlights:
Homogenizer-assisted extraction (HAE) is adequate for carotenoid extraction in peach palm epicarp.
The lipid extract from the peach palm epicarp is a source of provitamin A.
Lipid extract obtained is a natural additive with potential for use in corn griddle cakes
Temporal Analysis of Northern Corn Leaf Blight (Exserohilum turcicum Pass. Leonard & Suggs) Epidemics
Full text linkField trials were conducted in six locations in central-northern Córdoba, Argentina, using four maize hybrids with varying resistance to northern corn leaf blight (NCLB), caused by Exserohilum turcicum. Naturally occurring NCLB epidemics were evaluated. We analyzed disease severity (S%), disease progress curve (DPC), area under the disease progress curve, final severity (FS%) and apparent infection rate (r). Disease progress curves were simultaneously analyzed by fitting nonlinear epidemiological models (Gompertz and Logistic). Ballesteros and Villa María were the localities with the highest FS in susceptible hybrids (45% and 37.5%, respectively). Levels of FS were below 5% in Jesús María, Río Segundo and Freyre, and under 1% in El Tío. The highest AUDPC values were also observed in Ballesteros and Villa María (2150.1 and 1335.7, respectively). In the other locations, AUDPC values remained under 320, with statistically significant differences in all cases (p< 0.05). The resistant hybrid exhibited the lowest apparent infection rate compared to the other genotypes. Epidemic progress displayed, to varying degrees, sigmoid-shaped curves characteristic polycyclic diseases. On average, the Gompertz model best fitted disease progress data across all evaluated genotypes with an R² of 0.909 and an adjusted coefficient (R2*) of 0.849. The temporal analysis provided key epidemiological insights into the maize-NCLB pathosystem, supporting the development of effective management strategies.
Highlights:
Temporal analysis differentiated maize hybrids by resistance levels to NCLB.
Gompertz model provided the best fit for NCLB epidemics.
Final severity, AUDPC, and infection rates confirmed differences in hybrid resistance to NCLB.
Understanding NCLB temporal dynamics supports the development of hybrid selection and integrated management strategies.
Epidemiological tools enhance disease progress prediction and optimize NCLB control timing.Field trials were conducted in six locations in central-northern Córdoba, Argentina, using four maize hybrids with varying resistance to northern corn leaf blight (NCLB), caused by Exserohilum turcicum. Naturally occurring NCLB epidemics were evaluated. We analyzed disease severity (S%), disease progress curve (DPC), area under the disease progress curve, final severity (FS%) and apparent infection rate (r). Disease progress curves were simultaneously analyzed by fitting nonlinear epidemiological models (Gompertz and Logistic). Ballesteros and Villa María were the localities with the highest FS in susceptible hybrids (45% and 37.5%, respectively). Levels of FS were below 5% in Jesús María, Río Segundo and Freyre, and under 1% in El Tío. The highest AUDPC values were also observed in Ballesteros and Villa María (2150.1 and 1335.7, respectively). In the other locations, AUDPC values remained under 320, with statistically significant differences in all cases (p< 0.05). The resistant hybrid exhibited the lowest apparent infection rate compared to the other genotypes. Epidemic progress displayed, to varying degrees, sigmoid-shaped curves characteristic polycyclic diseases. On average, the Gompertz model best fitted disease progress data across all evaluated genotypes with an R² of 0.909 and an adjusted coefficient (R2*) of 0.849. The temporal analysis provided key epidemiological insights into the maize-NCLB pathosystem, supporting the development of effective management strategies.
Highlights:
Temporal analysis differentiated maize hybrids by resistance levels to NCLB.
Gompertz model provided the best fit for NCLB epidemics.
Final severity, AUDPC, and infection rates confirmed differences in hybrid resistance to NCLB.
Understanding NCLB temporal dynamics supports the development of hybrid selection and integrated management strategies.
Epidemiological tools enhance disease progress prediction and optimize NCLB control timing.
Enterococcus gallinarum CRL 1826 as a probiotic for ranaculture: in vitro safety, technological, and physiological properties:
Full text linkThis study aimed to progress in designing a probiotic containing autochthonous Enterococcus gallinarum CRL 1826 for application during the life cycle of Lithobates catesbeianus in hatchery conditions. We assessed bacterial resistance to chemotherapeutics used in ranaculture, the presence of genes encoding virulence factors (VF) and vancomycin resistance, and bacterial survival and maintenance of beneficial properties after freeze-drying and storage. The strain exhibited resistance to antiseptics, sensitivity to most chemotherapeutics, presence of vanC, and absence of VF genes. It demonstrated resistance to freeze-drying and the highest survival when using skim milk+sucrose and storage at 4°C for 24 months. It also displayed bacteriocin activity against Listeria monocytogenes. Pre-lyophilized and lyophilized cultures grew/resisted individual gastrointestinal conditions and simulated gastrointestinal digestion, keeping bacteriocin activity and surface properties. For the first time, we demonstrated that E. gallinarum CRL 1826 is a safe bacterium with technological and physiological properties that would allow bullfrog gut colonization. These studies are essential for progressing towards selecting E. gallinarum CRL 1826 as a probiotic to prevent epizootics during bullfrog breeding and control foodborne bacteria, potentially improving growth performance of L. catesbeianus.
Highlights:
Enterococcus gallinarum CRL 1826 was sensitive to chemotherapics used in ranaculture.
The strain did not display virulence and transferable vancomycin resistance genes.
The dried strain showed great survival and bacteriocin activity for 24 months’ storage.
The LAB resisted the gastrointestinal conditions and kept its bacteriocin activity.This study aimed to progress in designing a probiotic containing autochthonous Enterococcus gallinarum CRL 1826 for application during the life cycle of Lithobates catesbeianus in hatchery conditions. We assessed bacterial resistance to chemotherapeutics used in ranaculture, the presence of genes encoding virulence factors (VF) and vancomycin resistance, and bacterial survival and maintenance of beneficial properties after freeze-drying and storage. The strain exhibited resistance to antiseptics, sensitivity to most chemotherapeutics, presence of vanC, and absence of VF genes. It demonstrated resistance to freeze-drying and the highest survival when using skim milk+sucrose and storage at 4°C for 24 months. It also displayed bacteriocin activity against Listeria monocytogenes. Pre-lyophilized and lyophilized cultures grew/resisted individual gastrointestinal conditions and simulated gastrointestinal digestion, keeping bacteriocin activity and surface properties. For the first time, we demonstrated that E. gallinarum CRL 1826 is a safe bacterium with technological and physiological properties that would allow bullfrog gut colonization. These studies are essential for progressing towards selecting E. gallinarum CRL 1826 as a probiotic to prevent epizootics during bullfrog breeding and control foodborne bacteria, potentially improving growth performance of L. catesbeianus.
Highlights:
Enterococcus gallinarum CRL 1826 was sensitive to chemotherapics used in ranaculture.
The strain did not display virulence and transferable vancomycin resistance genes.
The dried strain showed great survival and bacteriocin activity for 24 months’ storage.
The LAB resisted the gastrointestinal conditions and kept its bacteriocin activity
Milk Production, Age at First Calving, and Calving-to-Conception Interval in Holstein, Brown Swiss, and Holstein x Brown Swiss Cows
Full text linkThe objective of this study was to evaluate milk production, age at first calving, and calving to conception interval in Holstein, Brown Swiss, and Holstein x Brown Swiss crossbred cows within a pasture-based dairy system in Argentina. The increasing global demand for more resilient and locally adapted dairy systems has led to a renewed interest in crossbreeding to enhance both reproductive and productive efficiency through heterosis. We analyzed data collected over 10 years (2014-2023) from 647 first-lactation cows, including Holstein, Brown Swiss, and Holstein x Brown Swiss crossbred cows. Data were examined using a mixed-effects linear model with breed, season, and their interactions as fixed effect and year as random effect. The results showed no significant differences in milk production between breeds or seasons. However, a significant interaction between breed and season was observed for the calving-to-conception interval, with a shorter interval for crossbred cows during spring-summer (102 days), compared to Holstein cows (156 days). This finding highlights a potential advantage of crossbreeding in reducing open days during the warmest months, thereby enhancing reproductive efficiency in pasture-based systems. This study suggests that crossbreeding can be a viable strategy for improving reproductive performance of dairy systems while maintaining similar milk yield compared to the other breeds, particularly in grazing systems.
Highlights:
Crossbreeding is increasingly considered in Argentina to improve resilience and efficiency in pasture-based dairy systems.
Milk yield, age at first calving, and calving-to-conception interval in 647 first-lactation cows over a ten-year period were evaluated.
No significant differences were found among breeds (Holstein, Brown Swiss cows and their cross) for milk yield or age at first calving.
A significant interaction between breed and season was detected for calving-to-conception interval.
Crossbred cows showed a shorter calving-to-conception interval than Holstein cows during spring and summer (102 versus 156 days).The objective of this study was to evaluate milk production, age at first calving, and calving to conception interval in Holstein, Brown Swiss, and Holstein x Brown Swiss crossbred cows within a pasture-based dairy system in Argentina. The increasing global demand for more resilient and locally adapted dairy systems has led to a renewed interest in crossbreeding to enhance both reproductive and productive efficiency through heterosis. We analyzed data collected over 10 years (2014-2023) from 647 first-lactation cows, including Holstein, Brown Swiss, and Holstein x Brown Swiss crossbred cows. Data were examined using a mixed-effects linear model with breed, season, and their interactions as fixed effect and year as random effect. The results showed no significant differences in milk production between breeds or seasons. However, a significant interaction between breed and season was observed for the calving-to-conception interval, with a shorter interval for crossbred cows during spring-summer (102 days), compared to Holstein cows (156 days). This finding highlights a potential advantage of crossbreeding in reducing open days during the warmest months, thereby enhancing reproductive efficiency in pasture-based systems. This study suggests that crossbreeding can be a viable strategy for improving reproductive performance of dairy systems while maintaining similar milk yield compared to the other breeds, particularly in grazing systems.
Highlights:
Crossbreeding is increasingly considered in Argentina to improve resilience and efficiency in pasture-based dairy systems.
Milk yield, age at first calving, and calving-to-conception interval in 647 first-lactation cows over a ten-year period were evaluated.
No significant differences were found among breeds (Holstein, Brown Swiss cows and their cross) for milk yield or age at first calving.
A significant interaction between breed and season was detected for calving-to-conception interval.
Crossbred cows showed a shorter calving-to-conception interval than Holstein cows during spring and summer (102 versus 156 days)