Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Tilapia production was 4.2 million tons in 2016, and almost half of the production came from aquaculture. At the same time, organic waste from breeding increases as the demand for tilapia production. An alternative to using such waste is the production of energy and organic fertilizers. The use of a co-substrate can help to achieve the moisture content necessary to feed the digester. The aim of this study was to determine the effect of the anaerobic co-digestion of bovine manure with residual sludge from tilapia fish breeding ponds in the production of sludge. Methane and CO2 production, chemical oxygen demand (COD), total solids (TS), total fixed solids (TFS), total volatile solids (TVS), volatile fatty acids (VFA), total nitrogen (TN), total phosphorus (TP) content, and microbiological parameters (fecal coliforms and salmonella) during composting were determined. The organic fertilizer obtained was evaluated by a germination and seedling growth assay. The results of this study showed that the mixture of bovine manure and residual sludge from tilapia fish breeding ponds (1:1) produced high methane and low CO2 in the composting process compared to the when these raw materials were composted individually. Alfalfa germination and seedling growth were significantly boosted by the application of sludge from the mixture of bovine manure with residual sludge from tilapia fish breeding ponds.  

Objective: Carry out an exploratory evaluation of sheep and goats grazing in a temperate pasture invaded by Senecio inaequidens, as a means of biological control of weeds in small-scale dairy systems (SSDS). Methodology: Crude protein (CP), neutral detergent fibre (NDF), and acid detergent fibre (ADF) were determined on pasture and Senecio samples. The effect of grazing by sheep and goats on the pasture was assessed by means of the height, density and soil cover of Senecio, and also sward height; and the live weight of the animals, daily weight gain and body condition score were recorded. Statistical analysis was by a 2x2 factorial design, with species (sheep or goat) and two grazing intensities at 28.3 or 50.3 m2/animal per day. Results: height, coverage and density of Senecio did not show significant differences (P>0.05), neither did sward height. The chemical composition of the pasture did not show statistically significant differences for the assessed periods either. Animal weight, body condition and daily weight gain did not show significant differences among the evaluated treatments (P>0.05). Implications: This is the first report evaluating sheep and goat grazing to control of Senecio invasion in temperate pasture in central Mexico. In addition, knowing the chemical quality of Senecio will allow decisions to be made for supplementation in grazing systems with sheep or goats. Conclusions: The grazing of sheep and goats reduced the number of Senecio plants in the assessed pasture, which indicates the possibility of controlling this weed by grazing sheep or goats over longer-term grazing.

Objective: To analyze the combined effect of food and larval density in order to determine the combination which the best results of the development, growth and survival of the Litopenaeus vannamei zoea are obtained. Desing/methodology/approach: The experiment consists of evaluating 16 treatments resulting from the combination of four larval densities: 100, 200, 300 and 400 larvae∙L-1 and four densities of C. muelleri as food, adjusting the rations in each of the three phases of the larval development. Results: The highest values of the development index (3.7), growth in terms of total length (2.86±0.09 mm) and dry (62.13±10.41 µg∙larvae-1) and organic weight (50.83±7.51 µg∙larvae-1), as well as the survival (88.30±9.10%) at the end of the experiment were obtained in treatment 3, which consisted of an intermediate larval density (300 larvae∙L-1) and low food concentration. Study limitation/implications: For a distintic species of microalga as food, it will be required to evalue the density to use. Conclusions. In order to optimize the performance of shrimp larval cultivation, the use of a density of 300 larvae∙L-1 and rations of 50 to 80×103 cel∙mL-1 of C. muelleri are recommended for future experimental cultivation of L. vannamei zoea.

Objective: Determine parasite prevalence, richness and load in wild mammals of Tangamanga I and II Parks in San Luis Potosí, SLP. Evaluate if infections are related to diet and/or climatic seasons. Design/methodology/approach: Analysis of fresh feces collected during three consecutive days in two sampling periods. Passive flotation techniques with sodium nitrate (qualitative) and McMaster (quantitative) were performed. Results: General prevalence observed was 36% (n=242). The parasite richness is formed by protozoa: Eimeria sp, Isospora sp and Cystoisospora sp; by the cestode Moniezia expansa and nematodes: Toxocara sp, Toxascaris sp, Ancylostoma sp/Uncinaria sp, Strongyloides sp, Trichuris suis and eggs from the Strongyles group. The parasite load observed in the case of protozoa ranged from 0 – 8,505 Oocysts per Gram of Feces, and from 0 – 1,400 Eggs per Gram of Feces in the case of helminths. Statistical analyzes showed that the prevalence of parasites does not depend on the climatic season, and only in Tangamanga II Park is the prevalence dependent on the diet (herbivores). Study limitations/implications: The preservation method used limits the coproparasitoscopic techniques that can be used (coproculture or coccidia sporulation). Findings/conclusions: The observed endoparasitic infections can be a potential risk to the health of animals, especially those of great genetic value (i.e., endangered species). In addition, the potentially zoonotic parasites observed represent a threat to the health of their keepers.

Objective: It is proposed to use the dolomite buffer capacity (BCDolomite) as a method of estimating the lime requirement, in soils that agronomically require a pH increase. Design/methodology/approach: In six soil samples, with different levels of response to the application of dolomite, the organic matter (OM), the content of sand, silt and clay, pH, K, Ca, Mg and potential acidity (Al+H) were determined. Assuming an apparent density of 1000 kg/m3 and a volume per hectare of 2000 m3, the soils were placed in polyethylene containers and treated with dolomite in doses equivalent to 0, 750, 1500, 2250 and 3000 kg/ha, establishing the BCDolomite as the inverse of the slope resulting from the relationship between the pH and the dose of dolomite. Results: In soils with a low response to the dolomite, the clay and OM content was 280 and 26 g/kg, respectively, and in high response soils, the clay and OM content was 240 and 47 g/kg, respectively. In all cases, in the relationship between pH and dose of dolomite, a simple and direct linear relationship was observed (R2 > 0.85; p < 0.05). Limitations on study/implications: The results obtained under controlled conditions show that BCDolomite constitutes a viable method to estimate the lime requirement, since, Findings/conclusions: the BCDolomite showed sensitivity to the complexity of the clay fraction and to the organic matter of the soil, for which the dolomite requirement is equal to the product between the desired pH increase and the BCDolomite.

OObjective: To carry out taxonomic studies that determine which formicine species are associated with thecultivation of Mexican lime.Design/Methodology/Approach: The study was conducted in eight municipalities and 59 localities of theApatzingán Valley region, Michoacán, México, where Mexican lime (Citrus aurantiifolia Swingle) is produced.A randomized complete blocks design was used in the experiment, where each municipality represented ablock. The repetitions were the number of collections, while the experimental unit was a lime sprout infestedwith Diaphorina citri and ants. The collections were direct and were made with an entomological aspirator. The values obtained were analyzed with the SAS University Edition software (2018).Results: The studied ants belong to the Dolichoderinae, Formicinae, Myrmicinae, Pseudomyrmecinae, andPonerinae subfamilies, which represent 15 genera and the same number of species. The subfamilies with thegreatest presence in the eight municipalities were: Myrmicinae, Dolichoderinae, and Formicinae. The specieswith the highest impact were Paratrechina longicornis, Forelius mccooki, and Atta mexicana, while Cardiocondyla minutior and Odontomachus sp. had a lower impact.Study limitations/implications: Social insecurity in the eight municipalities and the new form of coexistence.Findings/Conclusions: The studied species prefer dry, warm, and disturbed sites.

Objective: Describe the agribusiness potential of the castor in Mexico through the collection and analysis of agricultural, industrial, and commercial information that allows decision-making for the formulation of future productive projects generating economic, social, and technological impacts. Design/methodology/ approach: The research is descriptive with a transactional design. The information was collected on national and international agri-food statistical and documentary information platforms. Results: In Mexico, different attempts have been made in commercial and research projects related to the cultivation, production, and transformation of castor oil, with not very encouraging results, due to the lack of knowledge in productive, technological, and commercial processes. However, the need for the industrial sector to import oil to produce high-value products is evident. Limitations/implications: Isolated efforts have been made by each of the actors in the castor agribusiness, which has prevented the sector's consolidation Findings/conclusions: An intelligent management of agricultural production must be implemented through the establishment of commercial crops with the adoption of basic technological packages applied to each region in particular, with great attention to the availability of planting seed, which should have agronomic potential, use of nutrition and management of pests and diseases, as well as foresee all the cultural tasks of maintenance of the crop and harvesting modality that guarantee yield in the field and quality raw material. Currently, there is a deficit in the castor oil market in the country, which leads to high business prospects and business opportunities.

Objective: Evaluate the effect of different levels of protected herbal choline (CHP) on productive performance, carcass characteristics and blood metabolites in female lambs. Design/methodology/approach: Fifty-two Hampshire x Suffolk (29.95 ± 3.90 kg initial live weight) were assigned to one of four treatments: 0, 0.3, 0.6 and 0.9 % choline kg-1 dry matter. The experimental design was completely randomized, and linear or quadratic tendencies were detected. Results: There were not treatment effects on productive variables, back fat and Longissimus dorsi muscle area with the addition of protected herbal choline in the diet (p>0.05). CHP linearly increased the concentration of cholesterol, glucose, albumins, globulins, total proteins (p<0.05) and phosphatidylcholine (p<0.10). The concentration of triglycerides had a quadratic response (p<0.05) to the addition of CHP. Study limitations/implications: The level of choline supplementation in sheep depends on whether the source is herbal or synthetic. Findings/conclusions: The addition CHP in female lamb diets increased the serum phosphatidylcholine concentration, changed the concentration of protein and lipid metabolites; however, productive performance was not improved. Key words: sheep, energetic metabolites, lambs, herbal choline.

Objective: Know variables of the reproductive component of the materials for manual cross-pollination purposes, for which the search for sexual synchrony is emphasized. Design/methodology/approach: Four materials were analyzed, two with white pulp and two with red pulp, of which it is unknown if they present sexual self-incompatibility, the synchrony in flowering is also unknown. The flowering phase and the variables that can shed light on its reproductive behavior were analyzed Results: It was found that the red materials present strong hercogamy, they cannot be self-fertilized; There is no floral synchrony either, but there is closeness between the date of anthesis in a pitahaya with white pulp and a red one, which would allow promoting cross-pollination. Limitations on study/implications: Hylocereus spp., is consumed in a large part of the world and has acquired a very strong importance since the industrial demand is increasing; however, several of the genotypes used in commercial production in Mexico show low fruit set compared to high floral emission, which is considered self-incompatibility. Findings/conclusions: The presence of hercogamy, stronger in the red-fleshed materials, indicates the existence of sexual self-incompatibility, explaining the fact that the materials emit a large number of flowers, but do not achieve fruit set.

The objective of this study was to analyze the process of incorporating improved varieties of avocado and its effect on the diversity, management and use in 54 orchards belonging to 25 members of the Rural Production Society of C.V. FRUFIDET Group in Tétela del Volcán, Morelos. A survey was applied to all members of society considering the characteristics of the orchards and the process of incorporating improved varieties of avocado to their orchards. The diversity associated with avocado cultivation was obtained through participant observation and a survey. A typology of orchards was carried out with an analysis of principal components. The results show that the improved avocado has replaced the peach crop by 67%, plum 12%, corn and beans 12%, pomegranate 6% and fig 3%. Three types of orchards were found: those that have replaced the previous crop with improved varieties of avocado (17%), those that have introduced avocado as one more species to their orchard in combination with other fruit trees (53%) and those that they maintain with fruit trees and Mexican varieties of avocado (30%). It is concluded that the improved varieties of avocado have been incorporated by 100% of the members of the organization. Its incorporation has caused the displacement of Mexican varieties of avocado and other fruit trees