Nitrogen nutrition and changes in the chemical attributes of the soil for cultivars of Brachiaria brizantha intercropped with Stylosanthes in different forage systems

ABSTRACT

Nitrogen in the soil-plant system is extremely complex, and any change in soil management or cultivated species can modify its dynamics. To minimize environmental problems and sustainably optimize agricultural production, it is necessary to understand the dynamics of nitrogen in the soil-plant system. Thus, the objective of this study was to evaluate plant nitrogen nutrition and changes in the chemical attributes of the soil for cultivars of Brachiaria brizantha intercropped with Stylosanthes in different forage systems. The experimental design consisted of randomized block experimental design was used, with three replicates. The treatments consisted of forage systems: Piata palisadegrass, Paiaguas palisadegrass, Stylosanthes cv. Campo Grande, row intercropping of Piata palisadegrass with Stylosanthes, mixed intercropping of Piata palisadegrass and Stylosanthes, row intercropping of Paiaguas palisadegrass and Stylosanthes, and mixed intercropping of Paiaguas palisadegrass and Stylosanthes. Evaluations were performed in winter, spring, summer, and autumn in the same plots and over a 2-year period. The intercropping of grasses and legumes positively influences the chemical characteristics of the soil and the nutritional status of the forage by improving the concentration of nutrients. Overall the row seeding method provided better nutrient concentrations. The second year provided higher nitrogen absorption but resulted in greater soil acidification.     

Managing “Marandu” palisadegrass and calopo pastures based on light interception

Light interception (LI) in grazing management has been an efficient tool to harvest forage under similar growth stage conditions. The objective was to define the best grazing management strategies (GMSs) based on LI in marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] R. Webster cv. Marandu) and calopo (Calopogonium mucunoides Desv. cv. Comum) mixed pastures. Three GMSs were evaluated in a randomized block design: rest period interrupted at 90% (90LI), 95% (95LI) and 100% (100LI) of LI. The experimental period was divided into four periods: rainy seasons and transitions (between rainy and dry seasons). Post-grazing stubble height target was 15 cm. Canopy height, forage mass, leaf area index (LAI), morphogenic variables and tiller demographic pattern were evaluated. Pre- and post-grazing canopy height increased at 100LI. Pre-grazing forage mass decreased over time in all GMSs. The relationship among canopy height, forage mass and LI was not constant throughout the experiment. Post-grazing forage mass was greatest at 90LI. There was an increase in legume mass throughout the experiment; however, the proportion of legume in pre-grazing forage mass was no more than 6.6% for all GMSs. Number of calopo branches per plant and LAI increased throughout the experiment while the number of plants decreased. The 95LI provided the best conditions for calopo development; however, the LI as a tool to determine the entry of animals in mixed pastures of marandu palisadegrass and calopo should be carefully applied, considering the seasonal variations in canopy botanical and structural composition under similar LI.     

Pomegranate Juice and Peel Extracts are Able to Inhibit Proliferation,Migration and Colony Formation of Prostate Cancer Cell Lines and Modulate the Akt/mTOR/S6K Signaling Pathway

Plant Foods for Human Nutrition - Pomegranate (Punica granatum) is known to contain polyphenols with many potential health benefits, including anti-tumoral, anti-inflammatory, and anti-microbial...     

Determination of Phenolic Compounds in Three Edible Ripening Stages of Yellow Guava (Psidium cattleianum Sabine) after Acidic Hydrolysis by LC-MS/MS

Plant Foods for Human Nutrition - Yellow guava (Psidium cattleianum Sabine) has received considerable attention in the last years because of their high content in bioactive compounds with potential...     

Growth of juvenile common snook (Centropomus undecimalis Bloch, 1792) reared at different temperatures and salinities: Morphometric parameters,RNA/DNA,and protein/DNA ratios

We investigated the growth of juvenile common snook (Centropomus undecimalis) reared at 25°C and 28°C and salinities of 0.3, 15, and 32 g L^?1. Total length, weight, RNA/DNA, and protein/DNA ratios were determined after 90 days of experiment. Higher growth was observed at 28ºC compared with 25°C, at the same salinity. At 28°C and 15 g L^?1 salinity, the weight (25.14 g) of juveniles was twice that of the juveniles reared at the lower temperature. At different salinities, only higher temperature affected growth, with higher weight values obtained at 15 g L^?1 in comparison with 0.3 and 32 g L^?1. Length was similar at 0.3 and 15 g L^?1. The RNA/DNA ratio was greater in juveniles reared at a salinity of 15 g L^?1 when compared with 0.3 and 32 g L^?1. This study shows that the combination of higher temperature and intermediate salinity promotes better growth of common snook juveniles.     

Autochthonous probiotic Lactobacillus sp. in the diet of bullfrog tadpoles Lithobates catesbeianus improves weight gain,feed conversion and gut microbiota

Dietary supplementation with probiotics in animal production is an alternative to antibiotics. In frog culture, studies involving native strains of probiotic bacteria and their effects on the performance and intestinal histology of farmed animals are scarce. Therefore, this study aimed to evaluate a diet supplemented with Lactobacillus sp. in tadpoles of Lithobates catesbeianus. This randomized test was performed with two dietary treatments: non‐supplemented control diet and diet supplemented with Lactobacillus sp., with nine replications. The growth performance of Lactobacillus sp., including its bacterial enzymatic activity and stability in feed, as well as colonization and histology of the intestinal tract, was evaluated after 42 days of experimentation. Animals fed with a supplemented diet showed higher weight gain and concentration of lactic acid bacteria in the gut and lower feed conversion. No significant difference was observed in survival, total heterotrophic bacterial count or histological change in the gut between the two treatments. The Lactobacillus sp. strain was able to colonize the intestinal tract and feed and remain at a high concentration of 10⁷ and 10⁶ CFU g^?1, respectively. It produced several enzymes, which might have contributed to the greater weight gain and lower feed conversion in the supplemented animals, thus demonstrating its probiotic potential for use as a dietary supplement in bullfrog tadpoles.     

Culture possibilities of the razor clam Ensis arcuatus (Pharidae: Bivalvia)

This study investigated razor clam Ensis arcuatus culture from larval rearing to commercial size to assess it's aquaculture potential. Broodstock was spawned several times in hatchery facilities to demonstrate that larval availability is not a constraint for hatchery production. Larval culture lasted 20 days, showing an average survival of 14.35%. The razor clam seed reached a size of 28.5 mm at 4 months. Seed culture is feasible; however, it is constrained by the fact that razor clams need to be buried. Higher survival was observed when culturing razor clam seed with a substrate (82–83%), irrespective of the substrate grain size, while containers held without a substrate showed a significantly lower survival (56.5%). We showed that it is possible to rear E. arcuatus juveniles in bottles, with survival as high as 94–95% being achieved. The length increase of the hatchery‐produced E. arcuatus over 600 days was described by the equation Ln L=4.5+(?141.17/t), where L is length in mm and t is time in days. On‐growing showed adequate survival rates and it took 2–3 years to reach commercial size.     

High P Availability in Brazilian Cerrado Soils Reduces Nodulation and Grain Yield of Soybean

The aim of this work was to evaluate the effect of phosphorus (P) levels on nodulation and soybean production components in Cerrado soils. The experimental design was randomized in blocks, with five replicates, and four consecutive crop seasons (2013/2014, 2014/2015, 2015/2016, and 2016/2017), being cultivated in the same experimental field area. In the first three crop seasons phosphate fertilization were carried out establishing the treatments of increasing levels of P: 0, 43.6, 87.3, 131.0, and 174.6 kg ha^?1, and an additional level (farm standard) of 42 kg ha^?1. The results of this work refer to the crop season 2016/2017 without different P application, evaluating the influence of content of previous crop seasons. The dry weight of roots, plant population, thousand grains weight, grain yield, nitrogen (N) and P content in leaves, number and dry weight of nodules were evaluated in the reproductive stages (R2 and R8) of soybean. Increasing levels of P in soil provided significant effects on nodulation, morphological components and production of soybean plants. Levels above 40 mg dm^?3 of P available in soil provided a reduction in the number and dry weight of the nodules that are highly correlated to reduction on grain yield.     

Development of a real-time PCR method based on duplo target plasmids for determining an unexpected genetically modified soybean intermix with feed components

The occurrence of intermixing, especially that resulting from genetically modified (GM) species, is increasingly becoming a problem in the delicate chain of feed and food quality control. Thus, a strategy is needed for precisely quantifying the presence of intermixing. An analytical assay based on real-time PCR has been developed; it can ascertain the extent of unexpected intermixing of GM soybean with maize meal. Three soybean-maize mix levels, with soybean intermix percentages of, respectively, 0.1, 0.5, and 1%, were prepared to simulate samples containing traces of soybean. As calibrator standards, ad hoc multiple-target pGEM-T plasmids containing soybean and maize reference genes in a 1:1 ratio were constructed. Four different maize endogenous genes, alcohol dehydrogenase 1 (adh1), high-mobility group protein a (hmga), invertase 1 (ivr1), and zein (zein), were assessed, each combined with the soybean endogenous lectin 1 (lect1) gene. Plasmids containing adh1-lect1 and zein-lect1 genes were found to be the most reliable calibration systems for this analysis, providing precise and accurate quantification results. Measuring the percentage of GM soybean intermixing makes it possible to calculate the actual transgenic component of the total sample.     

Seaweed Blends as a Valuable Source of Polyunsaturated and Healthy Fats for Nutritional and Food Applications

Seaweeds are considered healthy and sustainable food. Although their consumption is modest in Western countries, the demand for seaweed in food markets is increasing in Europe. Each seaweed species has unique nutritional and functional features. The preparation of blends, obtained by mixing several seaweeds species, allows the obtaining of maximum benefits and ingredients with single characteristics. In this work, five seaweed blends, commercially available and produced under organic conditions in Europe, were characterized. The proximal composition included contents of ash (20.28–28.68% DW), proteins (17.79–26.61% DW), lipids (0.55–1.50% DW), and total carbohydrates (39.47–47.37% DW). Fatty acid profiles were determined by gas chromatography–mass spectrometry (GC–MS), allowing quantification of healthy fatty acids, namely n-3 and n-6 polyunsaturated fatty acids (PUFA), and calculation of lipid quality indices. Each blend showed a characteristic PUFA content in the lipid pool (35.77–49.43% of total fatty acids) and the content in essential and healthy n-3 PUFA is highlighted. The atherogenicity (0.54–0.72) and thrombogenicity (0.23–0.45) indices evidenced a good nutritional value of lipid fractions. As nutritional and environmentally attractive products, the consumption of the studied seaweed blends can contribute to a healthy lifestyle.