Caprine toxoplasmosis in Southern Brazil: a comparative seroepidemiological study between the indirect immunofluorescence assay,the enzyme-linked immunosorbent assay,and the modified agglutination test

Tropical Animal Health and Production - This study investigated the prevalence of caprine toxoplasmosis in goat herds from Southern Brazil by the indirect immunofluorescence assay (IFA), and...     

Distribution and diversity of leaf-cutting ants in Northeastern Argentina: species most associated with forest plantations

Abstract

Leaf-cutting ants (LCA) are considered one of the main herbivores and one of the most destructive pest insects of the Neotropics. Northeastern Argentina harbors the greatest species richness of these ants and in turn comprises the highest surface with forest plantations. Our aim was to establish which species of leaf-cutting ants are most commonly associated with forest plantations by analyzing their geographic distribution using published and unpublished species occurrence data. Also, estimate their potential areas of distribution along a latitudinal gradient that entirely encompasses northeastern Argentina using Ecological Niche Modeling. Only seven of the 20 species recorded were strongly associated with productive systems along the gradient, but only 2–3 species in each region could be considered high-risk species for forest plantations. High-risk species composition shows a turnover between regions. Our models show the potential distribution areas where LCA could become more abundant and dominant, and possibly causing a detrimental effect on the forest plantations in the studied region. We find that ecological niche models are useful tools to assess the environmental suitability of important LCA.     

Temperature in relation to phosphorus nutrition in Chinese cabbage

Chinese cabbage plants [Brassica pekinensis (Lour) Rupr. cv. Nagaoka 50] were cultivated experimentally for two years (1993 and 1994) using a semi‐forcing technique of floating rowcovers, polyethylene (T₁), polypropylene (T₂), versus no floating row‐covers, control (T₀). Five samplings were made, taking four plants per each replication and total phosphorus (P) (P_total), inorganic P (P_i), and calculated organic P (P_org) were determined as well as foliar acid phosphatase activity (FAPA). The aerial and root temperatures of the treatments T₁ and T₂ exceeded those of T₀. The P_total concentration showed no significant variations with treatment, whereas the P_i concentrations increased in T_i and T₂ and P_org decreased in both treatments with respect to T₀. The FAPA was influenced a similar way as P_i, raising with temperature. The contents (mg plant^‐1) of P_tolal, P_i, and P_org were greater in T₁ and T₂ than in T₀, and this could be due to the fact that the highest temperatures (root and aerial zone) generated by the plastic rowcovers favored the absorption of P, thereby boosting FAPA and the fresh and dry weights, and yield.     

Thermal Biology of Liorhyssus hyalinus (Hemiptera: Rhopalidae) and Nysius simulans (Hemiptera: Lygaeidae), Fed on the Milky Stage of Maize Grains

When quinoa, Chenopodium quinoa Willd., is cultivated in South America outside of its Andean origin, the heteropterans Liorhyssus hyalinus (Fabricius) and Nysius simulans Stål may emerge as important pests. Here we studied the development and reproduction of both species at different constant temperatures in the laboratory. Egg and nymphal development were investigated at 18, 22, 26, 30, 34, and 36°C. For both species, egg incubation time significantly decreased as the temperature increased. Nymphs did not successfully develop at 18°C and the total nymphal time significantly decreased as the temperature increased from 22 to 36°C. Based on a linear day-degree (DD) model, the lower developmental threshold (LDT) temperatures for eggs and nymphs were estimated to be 16.0 and 17.9°C for L. hyalinus, and 16.1 and 19.7°C for N. simulans, respectively. Thermal requirements for egg and nymphal development were 68.6 and 114.8 DD for L. hyalinus, and 77.7 and 190.3 DD for N. simulans, respectively. Reproduction and adult longevity were studied at 22, 26, 30, and 34°C. For both species preoviposition time decreased as temperature increased, and the oviposition period was longest at 26°C. The highest fecundity and egg viability were observed at 30°C, whereas longevities were higher at 22–26°C than at 30–34°C. As the lowest tested temperatures were not suitable to both heteropterans and 30°C was found to be the optimal temperature for development and reproduction, peak densities are expected in warm areas and seasons.     

Neutrophilic myeloperoxidase index and mean light absorbance in neonatal septic and nonseptic foals

Background: Two neutrophilic indices reported by the ADVIA 120 Hematology Analyzer, neutrophilic myeloperoxidase index (MPXI), and mean light absorbance (neutrophil X mean [NXM]) have been proposed as indicators of systemic inflammatory disease in horses and of neutrophil activation in coronary ischemic syndromes in people. Objective: The aim of this study was to evaluate NXM and MPXI in healthy, sick nonseptic, and sick septic foals to determine whether conditions likely associated with neutrophil activation result in decreases in these variables. Methods: In this retrospective study, CBC data from 61 neonatal foals presented to the Equine Teaching Hospital of Barcelona were evaluated for correlations between MPXI, NXM, percentage of large unstained cells, neutrophil count, and percentage of band neutrophils. Results obtained in septic (n=32), sick nonseptic (n=22), and healthy foals (n=7) were compared. In addition, results recorded in septic/neutropenic (n=12), septic/non‐neutropenic (n=20), nonseptic/neutropenic (n=8), nonseptic/non‐neutropenic (n=14), and healthy foals (n=7) were also compared. Results: A weak negative correlation was found between MPXI and neutrophil count and between NXM and percentage of band neutrophils. Septic/neutropenic foals had significantly higher MPXI values (median 17.9, minimum–maximum 4.7–42.5) than did septic/non‐neutropenic (1.5, ?24.4 to 22.3), nonseptic/neutropenic (6.6, 0.6–17.9), and nonseptic/non‐neutropenic foals (8.8, ?10.1 to 16.8) but did not differ significantly from controls (12.8, ?8.5 to 20.4). Conclusions: Significant differences in NXM or MPXI were not found when disease groups were compared with controls; however, septic/neutropenic foals had significantly higher median MPXI than other groups of sick foals. Further prospective studies are needed to clarify if this finding is related to decreased neutrophil function or activation in septic/neutropenic foals.     

Gamma-linolenic Acid from Fifty-seven Ribes Species and Cultivars

Plant Foods for Human Nutrition - γ-linolenic acid (GLA, 18:3n-6) is a bioactive fatty acid (FA) that exerts several healthy actions; however, its occurrence is restricted to a few oils. The...     

Agronomic characterization of diploid hybrid families derived from crosses between haploids of the common potato and three wild Argentinian tuber-bearing species

Five diploid hybrid families derived from crosses between haploids of three Argentinian cultivars and three diploid wild species,Solanum gourlayi, S. chacoense andS. spegazzinii, were evaluated in a field experiment in Balcarce. All plants were androsterile and, thus, could not be screened for 2n pollen production. Data on agronomic tuber traits were statistically analyzed. Differences among families were non-significant for tuber number/plant, but were significant for tuber weight/plant and dry matter content (with values above 21.0% in two of them). The relative frequencies of tubers in the categories established for size, skin texture, and eye depth were family dependent, but they were familiy independent in the categories established for tuber shape and skin color. Great morphological variability was detected for all the traits studied, and plants with high yield and high dry matter content were identified. These families can be used as sources of germplasm in breeding and to explore heterotic responses in 2x × 4x crosses, given the capacity of some plants to produce 2n eggs, as found in a related investigation.     

The Reuse of Water on the Culture of Pacific White Shrimp,Litopenaeus vannamei,in BFT System

The use of the same water over multiple culture cycles in a biofloc technology system can be highly beneficial. This study evaluated the effect of different levels of biofloc‐rich water on selected water quality indicators and on the productive performance of Pacific white shrimp, Litopenaeus vannamei, juveniles (3.5 g) stocked at 312 juveniles/m³ and cultured under conditions of no water exchange. The study was performed over a 30‐d period in an 800‐L tank system. A total of four biofloc enrichment levels (25, 50, 75, and 100%) and control (0%) were tested with three replicates each. Significant differences in nitrogen compounds were found between the biofloc‐enriched water and the zero‐enrichment treatment. No statistically significant differences among the biofloc‐enriched treatments were found in survival, final weight (8.25 g), and feed conversion ratio (FCR) (1.08). The shrimp raised in clear seawater (i.e., a 0% biofloc enrichment) were significantly smaller (7.37 g vs. 8.25 g) and showed a higher FCR (1.52 vs. 1.08) than the shrimp cultured in the biofloc‐rich water. Nevertheless, no differences in yields were found between treatments. The results of this study suggest that culture in biofloc‐enriched water produces higher levels of water quality and shrimp performance than culture in natural seawater.