Epiphytism on Blades of the Edible Kelps Undaria pinnatifida and Saccharina latissima Farmed under Different Abiotic Conditions

The kelps Undaria pinnatifida and Saccharina latissima are economically valuable edible seaweeds. Although epiphytism is a major problem affecting the productivity and quality of farmed seaweeds, studies of its effects on kelp aquaculture are scarce. We investigated the effects of epiphytism in two U. pinnatifida and S. latissima culture grounds located in two different parts (exposed and sheltered) of a bay (ría) in Galicia (NW Spain). Epiphytic organisms on blades were identified and their abundance was documented. The percentage of the total blade covered with epiphytes was measured for both kelp species in order to estimate the blade biomass that must be discarded during processing for human consumption. Algae, hydroids, and crustaceans were the most common epiphytic organism on kelp blades; colonies of the hydroid Obelia geniculata and harpacticoid copepods were the most abundant epiphytes. Abundance of epiphytes on the blades of both kelps was significantly higher for fronds growing in the sheltered area of the bay compared to those farmed at the exposed location. Different environmental conditions and other factors, such as the proximity of mussel cultures to kelp cultures, may be important contributors to epiphytism. The results presented here can be used to devise better ways for kelp aquaculture facilities to diminish the negative effects of epiphytism.     

Hypotensive and vasorelaxant effects of ethanolic extract from Jatropha gossypiifolia L. in rats

The present work was carried out to examine the hypotensive effects of ethanolic extract (EE) from Jatropha gossypiifolia L. The oral administration of EE (125 or 250 mg kg(-1) day(-1)) caused a significant and dose-dependent reduction of the systolic blood pressure. The concentration-response curves to norepinephrine (NE) or Ca(2+) were non-parallelly shifted to the right and the maximum contractile responses were concentration dependently depressed by EE (0.1 or 0.5 mg/ml) in endothelium-deprived mesenteric artery. The cumulative additions of EE (0.1-30 mg/ml) caused a concentration-dependent relaxant response in endothelium-deprived mesenteric artery precontracted with NE or Ca(2+). In conclusion, our results have shown that the EE from J. gossypiifolia L. can elicit hypotension, by oral via, in conscious normotensive rats and vasorelaxant activity on rat mesenteric rings precontracted with NE or Ca(2+).     

Evaluation of resistance in different cowpea cultivars to Callosobruchus maculatus infestation

Cowpea [Vigna unguiculata (L.) Walp] seeds are an important source of nutrients for human and animal. However, part of the seed production is lost due to insect attacks, mainly by the weevil Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae), a major pest of stored cowpeas. An efficient method for controlling seed infestation is the use of insect-resistant cultivars. In this work, we studied the resistance of different cowpea Brazilian cultivars (BRS) to infestation and damage by C. maculatus. Our results showed that some cultivars interfered in female oviposition. The time necessary for the larvae to perforate the seed coat of some cultivars increased up to 40 %. No relationship between seed coat thickness, textures, or pigmentation and the larval ability of crossing seed coats was observed. Larval survival was also affected by cowpea cultivars. In BRS Xiquexique, only 30 % of the larvae survived at 20 days after oviposition. The weight of larvae developed into BRS Pajeu, and BRS Xiquexique cultivars decreased about 50 %. Cysteine protease, α-glucosidase, and α-amylase activities decreased in larvae developed in some cultivars, mainly in Pajeu, Guariba, Tucumaque, and Xiquexique. Adult emergence also decreased in Xiquexique, Pajeu, Tucumaque, and Paraguaçu BRS cultivars. A direct relationship between higher infestation and lower seed germination and seedling growth potential was observed. From these data, we would recommend the use of Pajeu, Guariba, Tucumaque, and Xiquexique BRS cultivars as a way to reduce cowpea infestation, and suggest that their resistance mechanism is related to the diminishment of larval digestive abilities.     

Effects of nanofertilizer and nano-plant hormone on soil chemical properties and microbial community in two different soil types

Application of nanotechnology in agriculture has been expanded to improve crop production. The impact of nanomaterials (NMs) on factors that influence the survival and function of beneficial microorganisms is a less studied aspect that needs to be better understood. Only a few studies have assessed the effects of NMs on beneficial soil microorganisms. This study was conducted to assess the effects of nanofertilizer FertiGroe^?N (FG-N) and nano-plant hormone HormoGroe^?auxin (...     

Amino acid profiles of muscle and liver tissues of Australian Merino,Damara and Dorper lambs under restricted feeding

Seasonal weight loss (SWL) is a major constraint in extensive animal production systems in the tropics and Mediterranean. The objective of this study was to characterize the amino acid profile of muscle and hepatic tissues of Australian Merino, Damara and Dorper lambs under restricted feeding to evaluate the impact of SWL at the metabolic and physiological levels. SWL induced generalized muscle protein breakdown among restricted groups of all breeds, with varying intensity. Dorper breed mobilized less muscle amino acids when under these conditions, with the Damara having frequent significant differences, namely by having lower amino acid concentrations in the muscle of restricted lambs. Damara lambs showed greater ability to catabolize branched‐chain amino acids in the muscle tissue, which indicates yet another mechanism that provides the Damara with the necessary tools to endure harsh conditions. Overall, the Damara breed mobilized more muscle amino acids than the other breeds, with a better capacity to catabolize branched‐chain amino acids in the muscle, while maintaining muscle structural integrity.     

Response surface optimization of antioxidants extraction from chestnut (Castanea sativa) bur

The chestnut bur, a forest waste product from chestnut processing in the food industry, was studied as a potential source of natural antioxidants. Extractions were performed using aqueous solutions of methanol or ethanol. Experiments were planned according to an incomplete 3³ factorial design to study the influence of temperature (25-75 °C), time (30-120 min) and solvent concentration (50-90%) on extraction yield and on extract properties: total phenols content, antioxidant activity (using the FRAP, DPPH and ABTS methods) and average molecular weights. All dependent variables were influenced by temperature and solvent concentration whereas the influence of time was almost negligible. Using the response surface methodology the optimal extraction conditions were selected: the highest temperature assayed (75 °C), the lowest solvent concentration (50%) and an extraction time of 75 min for the methanolic extractions and of 30 min for the ethanolic ones. Under those conditions the values predicted for extraction yield and total phenols content were 18.95% and 36.32 g GAE/100 g extract for the methanolic extract and 17.95% and 26.11 g GAE/100 g extract for the ethanolic ones. Methanolic extracts showed superior total phenols content and antioxidant properties and slightly higher extraction yields than ethanolic extracts; however, ethanol is recommended for food applications due to its GRAS (Generally Recognized as Safe) qualification. Gallic acid esters of glucose, ellagic acid and small proportions of quercetin-3-β-d-glucoside, phenolic compounds with demonstrated antioxidant properties, were identified in chestnut bur extracts by RP-HPLC-ESI-TOF.     

Determination of the More Adequate Modified Agglutination Test Cut‐off for Serodiagnosis of Toxoplasma gondii Infection in Sheep

Toxoplasmosis is one of the most common food borne disease world‐wide. Among food animals, sheep seems to having higher prevalence of Toxoplasma gondii infection. However, there is no consensus about the best cut‐off for serodiagnosis in sheep. To estimate the more adequate cut‐off value of Modified Agglutination Test (MAT) for serodiagnosis in sheep, a commercial ELISA kit was used as a golden standard. Evaluation of the optimal sensitivity and specificity was calculated using Youden’s J‐statistics. Values obtained were used to estimate the prevalence of sheep toxoplasmosis. One thousand four hundred and sixty seven blood samples were collected randomly from 160 farms from northern Portugal, representing approximately 10% of the ovine population from the region. All sera were tested for anti‐T. gondii antibodies using the MAT. One hundred nine sheep (7.4%) presented a MAT titer ≥1 : 80; 45 (3.0%) a MAT titer of 1 : 40; 97 (6.6%) a MAT titer of 1 : 20 and 1216 (83.0%) a MAT titer ≤1 : 20. The best Youden’s J‐statistic was obtained at 1 : 20 titer (0.752), with 86.15% of sensitivity and 89.09% of specificity with negative and positive predictive values of 90.32% and 84.48% respectively, suggesting that the 1 : 20 was the most appropriate cut‐off for serodiagnosis of toxoplasmosis in sheep. Assuming this cut‐off, the prevalence of toxoplasmosis in the studied population was 17.1% and 92 (57.5%) of the 160 studied flocks having one or more positive sheep. Those results indicate that toxoplasmosis in Portugal should be considered in the differential diagnosis of abortions in sheep and neurological signs in lambs. Furthermore, while Portugal produces ovine meat for internal consumption and for exportation, isolation of T. gondii from ovine meat and further characterization of the isolates will be needed to understand the risk that ovine toxoplasmosis may represent for human health.