Effects of Ambient Nitrite on Amazon River Prawn,Macrobrachium amazonicum,larvae

The effects of nitrite concentration on larval development of Amazon river prawn, Macrobrachium amazonicum, were studied in laboratory. In Experiment 1, larvae were reared in 600‐mL glass beakers filled with 300‐mL water with nitrite concentration of 0, 0.2, 0.4, 0.8 and 1.6 mg/L NO₂‐N. In Experiment 2, total ammonia nitrogen (TAN, NH₃‐N + NH₄‐N) excretion were analyzed in zoea (Z) I, III, VII and IX exposed to 0, 0.4, 0.8 and 1.6 mg/L NO₂‐N. In both experiments each treatment was conducted in five replicates. The experiments were carried out in test solutions at 10 salinity, constant temperature 30 C and 12:12 h daylight : darkness regime. Survival, productivity, weight gain and larval stage index decreased linearly with increasing ambient nitrite concentration. However, there was no significant difference among larvae reared at concentration ranging from 0 to 0.8 mg/L NO₂‐N by ANOVA in all variables. Individual ammonia‐N and mass‐specific ammonia‐N excretion increased in ZI and ZIX, was almost constant in ZIII and decreased in ZVII from 0 to 1.6 mg/L NO₂‐N. The relationship between individual TAN and body mass suggested that 1.6 mg/L NO₂‐N stress the larvae. Despite of the effects of nitrite on larvae follow a dose‐dependent response and shows large variability among individuals, levels below 0.8 mg/L may be used as a general reference in commercial hatcheries, which should be applied carefully.     

Cryptosporidium species screening using Kinyoun technique in domestic cats with diarrhea

Cryptosporidium is a coccidian that can lead to diarrhea, especially in immunosuppressed individuals. Retroviruses are considered a primary cause of immunosuppression in cats. Fecal specimens and blood collected from the 60 cats were evaluated for the presence of acid-fast cryptosporidia in three consecutive stool samples and for feline leukemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibody by ELISA testing. Five animals (8.33%) shedding oocysts were found, one was both FIV- and FeLV-negative and four were FeLV-positive.     

Effects of plant extracts from Stryphnodendron adstringens (mart.) coville,Lafoensia pacari a. st.-hil,copaifera spp., and Pterodon emarginatus Vogel on in vitro rumen fermentation

The effects of doses CTL (0 mg), 30, 300 and 3000 mg/L of extracts from Stryphnodendron adstringens (Mart.) Coville (SA), Lafoensia pacari A. St.-Hil (LP), Copaifera spp. (CO) and Pterodon emarginatus Vogel (PE) on ruminal fermentation were investigated in eight experiments conducted in randomized complete block designs. The in vitro system contained four fermentation vessels. Each treatment was allocated in one vessel in each run. Incubation was run four and five times with diets 50:50 and 10:90 (roughage to concentrate ratio) respectively. Incubation vessel was the experimental unit, and each incubation run was a block. All plant extracts negatively affected DM degradation at 3000 mg/L. In diet 50:50, SA-3000 increased the molar proportion of propionate (p < 0.05), yet it decreased the concentration of fermentation products (p < 0.05); LP-300 reduced ruminal ammonia nitrogen (NH₃-N; 98 vs. 120 mg/dl for LP-300 and average of CTL and LP-30, respectively) and isobutyrate (p < 0.05); CO-300 reduced (p < 0.05) NH₃-N (98 vs. 123 mg/dl for CO-300 and average of CTL and CO-30, respectively); and P. emarginatus had no positive effects on rumen fermentation (p > 0.05). In diet 10:90, SA-300 reduced (p < 0.001) NH₃-N and total volatile fatty acids (VFA); LP-30 increased (p < 0.05) total VFA (85 vs. 63 mM for LP-30 and CTL, respectively), molar proportions of acetate and propionate, and had lower C₂:C₃ than CTL (3.6 vs. 4.3, respectively); CO-300 decreased acetate and increased propionate, reducing C₂:C₃ (p < 0.001; 2.8 vs. 3.6 for CO-300 and average of other doses, respectively); PE-30 and PE-300 reduced NH₃-N by 14% and increased total VFA by 29% compared with CTL (p < 0.05). Further in vivo investigations may consider L. pacari (LP-30), Copaifera spp. (CO-300) oleoresin and P. emarginatus oleoresin (PE-30 and PE-300) in diets with high inclusion of concentrate.     

Body weight and protein content in the haemolymph of females of the zoophytophagous predator Brontocoris tabidus (Heteroptera: Pentatomidae) with different diets and ages

Journal of Plant Diseases and Protection - The effect of different diets [1. Tenebriomolitor L. (Coleoptera: Tenebrionidae) pupae; 2. T. molitor pupae and Eucalyptus cloeziana plants; 3. T. molitor...     

Evaluation of the Genetic Diversity of Xylella fastidiosa Strains from Citrus and Coffee Hosts by Single-Nucleotide Polymorphism Markers

ABSTRACT The aim of this study was to obtain information about genetic diversity and make some inferences about the relationship of 27 strains of Xylella fastidiosa from different hosts and distinct geographical areas. Single-nucleotide polymorphism (SNP) molecular markers were identified in DNA sequences from 16 distinct regions of the genome of 24 strains of X. fastidiosa from coffee and citrus plants. Among the Brazilian strains, coffee-dependent strains have a greater number of SNPs (10 to 24 SNPs) than the citrus-based strains (2 to 12 SNPs); all the strains were compared with the sequenced strain 9a5c. The identified SNP markers were able to distinguish, for the first time, strains from citrus plants and coffee and showed that strains from coffee present higher genetic diversity than the others. These markers also have proven to be efficient for discriminating strains from the same host obtained from different geographic regions. X. fastidiosa, the causal agent of citrus variegated chlorosis, possesses genetic diversity, and the SNP markers were highly efficient for discriminating genetically close organisms.     

The Eberhart and Russel’s Bayesian method used as an instrument to select maize hybrids

Adaptability and stability analysis methods that use a priori information allow identifying and selecting potentially productive genotypes with greater accuracy. The aim of the current study is to use the Eberhart and Russel’ Bayesian method as an instrument to analyze the adaptability and stability of hybrid maize cultivars and to assess the efficiency of using the distribution of informative and non-informative priors to select cultivars. Twenty-five (25) hybrid maize cultivars were assessed in 11 environments located in the Brazilian Northeastern region, during 2012 and 2013, according to a complete randomized block design, with two repetitions. The Eberhart and Russel’s methodology was performed in the GENES software, whereas the Bayesian procedure was implemented in the free software R, by using the MCMCregress function of the MCMCpack package. The adaptability and stability parameters values and the credibility intervals have shown that the Eberhart and Russel’s method via Bayesian technique has shown greater stability-estimation accuracy and greater efficiency in recommending cultivars adapted to favorable and unfavorable environments. The Bayesian methods using priories informative (M1) and few informative (M2) distributions have presented the same genotype classifications in the comparison between a priori distributions; however, according to the Bayes Factor, the M1 was the most adequate distribution to help finding more reliable estimates.     

Relationships between Doses and Application Methods of Phosphorus and Corn Nutrition Status and Grain Yield

The broadcast application of phosphate fertilizers may be more effective than localized application methods for the growth of corn in medium textured oxisol, which have lower phosphorus (P) adsorption capacity. This study aimed to evaluate three phosphate fertilizer application methods at five different doses onto corn grown in oxisol, over two seasons. The experiment was conducted on corn crops in Passos city, Minas Gerais state, Brazil. Stripes with split plots were used to investigate the different application methods where each plot represented double furrow, single furrow, or broadcast application. Within the sub plots, the five doses (0.0, 50, 100, 200, and 400 kg ha^?1) of phosphorus pentoxide (P₂O₅) as granulated monoammonium phosphate (MAP) were applied. Four replications were used. The doses were reapplied in the second cultivation year only for the localized treatments (single and double furrow). The nitrogen in the MAP was held constant among treatments. The corn grain yield in both years was dependent upon both dose and application method, primarily for the single furrow and broadcast methods. In the first year, the broadcast application method of P fertilizer at a estimated dose of 319 kg ha^?1 of P₂O₅ provided a greater accumulated yield over two seasons. Broadcast application is therefore a viable method for growing corn with a reduced spacing distribution on medium textured oxisol.