Biochar as a strategy to manage plant diseases caused by pathogens inhabiting the soil: a critical review

Phytoparasitica - The current agricultural scenario faces a range of challenges, with phytosanitary ones being paramount. In most cases, plant diseases are treated with chemicals; however, they...     

Genetic parameters for nitrogen fractions content in Mexican Brown Swiss cattle milk

Tropical Animal Health and Production - Nitrogen plays an important role in the metabolism of living organisms due to the variety of physiological functions that involve molecules that contain it....     

Quantification of plasma reduced glutathione, oxidized glutathione and plasma total glutathione in healthy cats

Glutathione is an important intracellular tripeptide with multiple functions. Abnormal glutathione metabolism is thought to play an important role in various diseases of cats. However, no data regarding concentration of plasma glutathione are available for domestic cats. This study discusses the development of a rapid, simple high pressure liquid chromatography method for measurement of reduced glutathione (GSH), oxidized glutathione (GSSH) and total glutathione (GSHt) in plasma, for the purpose of establishing baseline data for future studies. The mean concentrations of GSH, GSSH and GSHt were 4.51+/-1 microM; 19.44+/-3.79 microM (expressed as GSH equivalent) and 23.59+/-3.89 microM, respectively. This is the first report of plasma glutathione concentrations in this species.     

Is the ballan wrasse (Labrus bergylta) two species? Genetic analysis reveals within‐species divergence associated with plain and spotted morphotype frequencies

The ballan wrasse (Labrus bergylta) is a marine fish belonging to the family Labridae characterized by 2 main morphotypes that occur in sympatry: spotty and plain. Previous studies have revealed differences in their life‐history traits, such as growth and maturation; however, the genetic relationship between forms is presently unknown. Using 20 recently developed microsatellite markers, we conducted a genetic analysis of 41 and 48 spotty and plain ballan wrasse collected in Galicia (northwest Spain). The 2 morphotypes displayed highly significant genetic differences to each other (F_ST = 0.018, P < 0.0001). A similar degree of genetic differentiation (F_ST = 0.025, P < 0.0001) was shown using the STRUCTURE clustering approach with no priors at K = 2. In this case, the frequency of spotty and plain morphotypes was significantly different (χ² = 9.46, P = 0.002). It is concluded that there is significant genetic heterogeneity within this species, which appears to be highly associated with the spotty and plain forms, but not completely explained by them. Given the previously demonstrated biological differences between morphotypes, and the present genetic analyses, we speculate about the convenience of a taxonomic re‐evaluation of this species.     

Effects of urea plus nitrate pretreated rice straw and corn oil supplementation on fiber digestibility,nitrogen balance,rumen fermentation,microbiota and methane emissions in goats

Background: Urea pretreatment is an efficient strategy to improve fiber digestibility of low quality roughages for ruminants. Nitrate and oil are usually used to inhibit enteric methane(CH_4) emissions from ruminants. The objective of this study was to examine the combined effects of urea plus nitrate pretreated rice straw and corn oil supplementation to the diet on nutrient digestibility, nitrogen(N) balance, CH_4 emissions, ruminal fermentation characteristics and microbiota in goats. Nine female goats were used in a triple 3 × 3 Latin Square design(27 d periods). The treatments were: control(untreated rice straw, no added corn oil), rice straw pretreated with urea and nitrate(34 and 4.7 g/kg of rice straw on a dry matter [DM] basis, respectively, UN), and UN diet supplemented with corn oil(15 g/kg soybean and15 g/kg corn were replaced by 30 g/kg corn oil, DM basis, UNCO).Results: Compared with control, UN increased neutral detergent fiber(NDF) digestibility(P 0.001) and copies of protozoa(P 0.001) and R. albus(P 0.05) in the rumen, but decreased N retention(-21.2%, P 0.001), dissolved hydrogen concentration(-22.8%, P 0.001), molar proportion of butyrate(-18.2%, P 0.05),(acetate + butyrate) to propionate ratio(P 0.05) and enteric CH_4 emissions(-10.2%, P 0.05). In comparison with UN, UNCO increased N retention(+34.9%, P 0.001) and decreased copies of protozoa(P 0.001) and methanogens(P 0.001). Compared with control, UNCO increased NDF digestibility(+8.3%, P 0.001), reduced ruminal dissolved CH_4 concentration(-24.4%, P 0.001) and enteric CH_4 emissions(-12.6%, P 0.05).Conclusions: A combination of rice straw pretreated with urea plus nitrate and corn oil supplementation of the diet improved fiber digestibility and lowered enteric CH_4 emissions without negative effects on N retention. These strategies improved the utilization of rice straw by goats.     

Evaluation of comparative advantages in the profitability and competitiveness of the small-scale dairy system of Tulancingo Valley,Mexico

This article combines a Policy Analysis Matrix with a sensitivity and poverty line analysis with the objective of evaluating the economic contribution of comparative advantages to the private profitability and competitiveness of small-scale dairy systems. For 1 year, socioeconomic data were collected from 82 farms selected from four strata via statistical sampling. Two scenarios were established to determine the quantitative contribution of comparative advantages: (1) a simulated scenario, which accounted for the cost of purchasing the total food and the opportunity cost of the family labour force (FLF), and (2) an actual production scenario, which accounted for the cost of producing food and eliminating the payment of the FLF and included other income. The E3 and E4 producers were the most profitable and competitive in the simulated scenario and actual production scenario. Of the four scales evaluated, the E2 and E1 producers were the most efficient in taking advantage of the economic contribution provided by the comparative advantages in their own production of food and employment of the FLF, in addition to accounting for other income, a condition that increased their profitability by 171 and 144% and competitiveness by 346 and 273%, respectively. The poverty results indicated that only E3 and E4 producers were non-vulnerable in the simulated scenario and actual production scenario. The purchase of food was the comparative advantage with the greatest sensitivity to cost increases in the two scenarios analysed, which exacerbated the effect on the E1 and E2 producers.     

Administration of carbetocin—a long-acting oxytocin analogue—before sperm collection by transrectal ultrasound-guided massage of the accessory sex glands in bucks (Capra hircus) and ibexes (Capra pyrenaica)

Transrectal ultrasonic-guided massage of the accessory sex glands (TUMASG) is a technique that allows collecting semen requiring few electrical stimuli or even no pulse. A long-acting analogue of oxytocin (carbetocin, 0.1 mg) was i.v. administered before TUMASG in 10 conscious bucks (Experiment 1) and 10 anaesthetized Iberian ibexes (Experiment 2) to shorten the time of semen collection, decrease the number of electrical stimuli and/or improve the semen quality. The ejaculated volume, concentration, quality parameters and kinetics variables of the sperm were determined in fresh semen. The time length of the procedures and the number of electric pulses applied were recorded. Furthermore, stress response indicators (number of vocalizations in Experiment 1; heart and respiratory rates, rectal temperature, cortisol levels, totals proteins and neutrophil-to-lymphocyte ratio in Experiment 2) were documented. In bucks, the administration of carbetocin tended to shorten the time needed for semen collection but no-showed differences in the fresh seminal quality. In the Iberian ibexes, there were no significant differences between groups in the time length of procedures or in the number of animals that ejaculated. Carbetocin administration only reduced the respiratory rate, did it modify fresh semen characteristics in ibexes. In conclusion, the administration of carbetocin did not appear as a useful tool to improve welfare during semen collection with TUMASG or semen quality in conscious bucks and anaesthetized ibexes, having only slight advantages related to the procedure.     

Parasite density and impaired biochemical/hematological status are associated with severe clinical aspects of canine visceral leishmaniasis

We have performed a detailed investigation in 40 dogs naturally infected with Leishmania infantum (syn. chagasi), subdivided into three groups: asymptomatic (AD = 12), oligosymptomatic (OD = 12) and symptomatic (SD = 16), based on their clinical features. Twenty non-infected dogs (CD) were included as control group. Serological analysis, performed by IFAT and ELISA, demonstrated higher antibodies titers in SD in comparison to the AD. A positive correlation was found between parasite density in the spleen and skin smears as well as the bone marrow parasitism with clinical status of the infection. We observed that the progression of the disease from asymptomatic to symptomatic clinical form was accompanied by intense parasitism in the bone marrow. It is likely that this led to the impaired biochemical/hematological status observed. Finally, we believe that the follow-up of these parameters could be a relevant approach to be used as markers during therapeutic and vaccine evaluations.     

The effect of land use change and ecotourism on biodiversity: a case study of Manuel Antonio,Costa Rica,from 1985 to 2008

Development in biodiversity rich areas is of global concern. While development may lead to socioeconomic benefits, this often comes concomitant with biodiversity loss and deforestation. Biodiversity rich areas present the opportunity for both improvements in socioeconomic conditions and conservation; however numerous challenges exist. Costa Rica’s Manuel Antonio National Park presents an ideal case study to investigate the balance between alternative forms of development which have contrasting environmental impacts. The Manuel Antonio region is a highly dynamic landscape experiencing deforestation, from agriculture, cattle ranching and oil palm plantations; and also reforestation from abandonment of land holdings and nature oriented tourism. Landscape dynamics are closely intertwined with the livelihoods and perspectives on biodiversity conservation of local communities, determining ecological sustainability. We use an analysis combining multi-temporal remote sensing of land cover dynamics from 1985 to 2008 with questionnaire data from local families on their socioeconomic status, perspectives on conservation, and perceived changes in local wildlife populations. Our results show that, while regeneration occurred and forest fragmentation in the area decreased from 1985 to 2008, Manuel Antonio National Park is rapidly becoming isolated. Decreasing ecological connectivity is related to the rapid expansion of oil palm plantations adjacent to the park and throughout the lowland areas. Perceived decreases in wildlife abundance and compositional change are evident throughout the area, with local communities attributing this primarily to illegal hunting activities. Nature based tourism in the area presents an effective strategy for conservation, including reductions in hunting, through increased valuation of biodiversity and protected areas, and socioeconomic advantages. However, without urgent efforts to limit deforestation and preserve the remaining forested corridor connecting the park to core primary forest, the ability to maintain biodiversity in the park will be reduced.