Oil extraction from lesquerella seeds by dry extrusion and expelling

Whole lesquerella seeds with 6% (as is) and 12% moisture content (MC) were extruded at different residence times by varying screw speeds and feed rates. The temperature of the extrudate was recorded and its MC was determined. The extent of seed cooking was evaluated by measuring the protein solubility and thioglucosidase (TGSase) activity in the extrudate. Uncooked whole seeds (UWS), whole seeds cooked in seed cooker (CWS), and extrusion-cooked seeds (ECS) were screw pressed and the crude oils were analyzed for foots, free fatty acid (FFA), phosphorus, calcium, magnesium, and sulfur. The screw speed and feed rates employed resulted in residence times ranging from 22 to 110 s. The corresponding exit temperatures of the extrudates ranged from 88 to143 °C. Seeds with 6% initial MC dried to 4.3% at extrudate temperatures ≤125 °C regardless of residence time, while seeds with 12% initial MC came out at 7–9% MC, Extruding seeds with 6 and 12% starting MC for 34 and 41 s, respectively, provided the same degree of cooking as that of 12% MC CWS. All CWS and ECS tested negative for TGSase activity. ECS with 6% initial MC generated much higher foots (6.4–9.4%) in the oil compared with that of the 12% MC ECS (1–1.7%). The crude oils from CWS had the lowest FFA content at 1.25%. Crude oils from UWS and ECS had FFA ranging from 1.4–2.8%. The crude oil from 12% MC CWS had 374 ppm sulfur which was 3–8× higher than what were found in crude oils from 6% MC CWS and ECS. The highest P (23 ppm), Ca (14 ppm), and Mg (6 ppm) levels in the crude oil were from 12% MC CWS, which were comparable to total degummed oils. An 81% oil recovery from 6% MC ECS (22 s residence time) was obtained at 19 rpm expeller screw speed. Increasing the expeller's screw speed from 19 to 37 rpm decreased the oil recovery by 0.2%/rpm, increased the throughput by 3.3 kg/rpm from 70 to 130 kg/h, and reduced the press load from 91 to 67%.     

Method for analysis of fatty acid distribution and oil content on a single Lesquerella fendleri seed

Lesquerella fendleri is a developing oilseed crop suitable for temperate growing regions in the US. The seed oil is rich in lesquerolic acid (57%) and could serve as a domestic source of hydroxy fatty acids. A method for the analysis of fatty acids and total oil content of a half or single lesquerella seed was developed. Lesquerella seeds are small with 1000 seed weights around 0.6 g (half seed mass of 200–500 μg). Conventional analytical balances provide mass accuracy to ±40 μg which fails to provide sufficient accuracy/precession (4–40% mass error) for the initial seed mass. A microbalance which measures to ±2 μg provided good reproducibility in initial seed weights but was not suitable for mass balance of the extracted oil. A normal phase HPLC coupled to an evaporative light scattering detector gave good response for oil in the mass range of 22 μg to 110 μg/mL. Therefore, micelle concentrations from single or half seed extractions could be determined with good reproducibility. This method was then evaluated on bulk seed that had been fractionated on a gravity table. Gravity table fractionation of L. fendleri seeds obtained from a large field plot provided seven fractions with increasing bulk density. These fractions were then analyzed in sets of 30 individual seeds and as an aggregate of 50 seeds. Oil content for individual seeds varied widely (15.6–44.2%) as did lesquerolic acid content (42.2–63.7%). The mean oil content increased (27–33%) with increasing bulk density (684–745 g/L). The mean lesquerolic acid content did not correlate with bulk density.     

Inclusion of weaning management group as a random effect in the genetic evaluation of postweaning traits in Nellore cattle

The objective of this study was to evaluate the impact of including weaning management group (WMG) as an uncorrelated random effect in the genetic evaluation of postweaning traits. Data from 186,507 Nellore animals' sons to 1,734 sires and 75,016 cows were analyzed. Three single-trait models were studied. These models included the contemporary group (CG) as a fixed effect and age of animal at measurement and age of dam at calving as covariates, in addition to the direct additive breeding value as random effect. The CGs for postweaning traits varied between models which included or not WMG as part of the concatenation of fixed effects. In the model in which WMG was not part of the CG, the trait was included as an uncorrelated random effect. The results suggest that although no significant effects were observed on genetic parameter estimates or animal ranking, the inclusion of WMG as an uncorrelated random effect increased the number of observations per CG and contributed to maintaining animals in the analysis that would be discarded because they were in a CG with a small number of observations. This model could therefore be recommended for the genetic evaluation of this Nellore population.     

Genetic association between milk yield,stayability, and mastitis in Holstein cows under tropical conditions

The objective of this study was to estimate genetic parameters for milk yield, stayability, and the occurrence of clinical mastitis in Holstein cows, as well as studying the genetic relationship between them, in order to provide subsidies for the genetic evaluation of these traits. Records from 5,090 Holstein cows with calving varying from 1991 to 2010, were used in the analysis. Two standard multivariate analyses were carried out, one containing the trait of accumulated 305-day milk yields in the first lactation (MY1), stayability (STAY) until the third lactation, and clinical mastitis (CM), as well as the other traits, considering accumulated 305-day milk yields (Y305), STAY, and CM, including the first three lactations as repeated measures for Y305 and CM. The covariance components were obtained by a Bayesian approach. The heritability estimates obtained by multivariate analysis with MY1 were 0.19, 0.28, and 0.13 for MY1, STAY, and CM, respectively, whereas using the multivariate analysis with the Y305, the estimates were 0.19, 0.31, and 0.14, respectively. The genetic correlations between MY1 and STAY, MY1 and CM, and STAY and CM, respectively, were 0.38, 0.12, and ?0.49. The genetic correlations between Y305 and STAY, Y305 and CM, and STAY and CM, respectively, were 0.66, ?0.25, and ?0.52.     

Vulnerability of rice and corn to climate change in the Philippines

The potential impact of climate change on rice and corn crops in the Philippines was assessed using preliminary results from four general circulation models and the Decision Support System for Agrotechnology Transfer. The results showed both increases and decreases in the yield of two rice varieties. The results for corn showed a consistent decrease in yield. The decrease in crop yield may be due to a shorter maturity period and an increase in potential evapotranspiration as a result of increased daytime and nighttime temperatures, which are critical to dry matter production. Rainfall in tropical areas such as the Philippines is generally high, and so a decrease in rainfall of only 10% may not affect the water supply significantly, but an increase of the same magnitude may affect crop production tremendously because of frequent occurrences of floods. One potential negative impact not included in this analysis is the effects of strong winds due to typhoons.     

Long-term understory recovery after mechanical fuel reduction in Mediterranean cork oak forests

In the Euro-Mediterranean region, mechanical fuel reduction is increasingly used in response to the mounting occurrence of catastrophic wildfires, yet their long-term ecological effects are poorly understood. Although Mediterranean vegetation is resilient to a range of disturbances, it is possible that widespread fuel management at short intervals may threaten forest structural complexity and the persistence of some plant species and functional types, with overall negative consequences for biodiversity. We used a chronosequence approach to infer woody vegetation changes in the first 70 years after understory clearing in upland cork oak (Quercus suber) forests, and to assess how these are affected by treatment frequency. Across the chronosequence there was a shift between plant communities with contrasting composition, structure and functional organization. Understory cover increased quickly after disturbance and a community dominated by pioneer seeder and dry-fruited shrubs (Cistus ladanifer, C. populifolius, Genista triacanthos, and Lavandula stoechas) developed during about 15 years, but this was slowly replaced by a community dominated by resprouters and fleshy-fruited species (Arbutus unedo, Erica arborea) >40 years after disturbance. During the first 15 years there were rapid increases in woody species richness, vertical structural diversity, cover by Q. suber juveniles and saplings, and shrub cover at <1.5 m strata, which levelled off or slightly declined thereafter. In contrast, tree species richness, tree density and density of arboreal A. unedo and E. arborea, vertical structural evenness, and cover at >1.5 m strata increased slowly for >50 years. Treatment frequency showed strongly negative relationships with species richness, structural diversity and evenness, and horizontal and vertical understory cover, particularly that of slowly recovering species. These findings suggest that fuel reduction programs involving widespread and recurrent understory clearing may lead to the elimination at the landscape scale of stands with complex multi-layered understory occupied by large resprouters and fleshy-fruited species, which take a long time to recover after disturbance. Fuel management programs thus need to balance the dual goals of fire hazard reduction and biodiversity conservation, recognizing the value of stands untreated for >50 years to retain ecological heterogeneity in Mediterranean forest landscapes.     

Relationship of host recurrence in fungi to rates of tropical leaf decomposition

Here we explore the significance of fungal diversity on ecosystem processes by testing whether microfungal ‘preferences’ for (i.e., host recurrence) different tropical leaf species increases the rate of decomposition. We used pairwise combinations of γ-irradiated litter of five tree species with cultures of two dominant microfungi derived from each plant in a microcosm experiment. The experiment was designed to test whether early leaf decomposition rates differed depending on relationships between the leaf litter from which the fungi were derived (i.e., the source plant) and the leaf substrata decomposed by these fungi in microcosms. Relationships tested were phylogenetic relatedness between the source and substratum leaves, and similarity in litter quality (lignin, N and P) between the source and substratum. We found a significant interaction between microfungi and leaf species (P<0.0001), and differences among the four classes of source–substratum relationships were highly significant (P=0.0004). Combinations in which fungal source leaves were of the same species or family as the substratum, or the fungal source resembled the substratum in quality had marginally faster decomposition than when the fungal source and substratum leaves were mismatched (i.e., unrelated and of dissimilar quality). In some microcosms, a basidiomycete contaminant had a strong additive effect on decomposition of Croton poecilanthus leaves resulting in faster decomposition than with microfungi alone (P<0.0001). Comparisons among leaf–microfungal combinations were made after the effect of the basidiomycete covariate was adjusted to zero. The data on microfungi suggest differential abundance in particular hosts, which contributes to species diversity of decomposer fungi in tropical forests, affects rates of decomposition.     

Atmospheric Total Suspended Particulate Trace Element Identification by XRF at Ilha Grande, State of Rio De Janeiro, Brazil

Phosphorus, manganese, sulfur (S), lead, and strontium of atmospheric total suspended particulate matter, sampled during the rainy season and the dry season 2002 at the Ilha Grande Island (Rio de Janeiro State, Brazil) have been analyzed by XRF techniques. The results showed total mean concentrations of 27?±?16 ng P m^-3, 11?±?7 ng Mn m^-3, 159?±?126 ng S m^-3, 4.3?±?2.6 ng Pb m^-3, and 208?±?148 ng Sr m^-3. Generally, there is no clear influence of the two different climatic periods on the concentrations of most analyzed trace elements, with exception of sulfur the mean concentration of which, during the dry season, is about 60% higher than during the rainy season. This is probably due to biomass burning, a common practice in the Brazilian Southeast and Amazon region and/or to the presence of marine aerosols. The linear correlation coefficients strongly suggest the same source for P, Pb, and Mn. Some Pb, Mn, and P concentrations are in the range of typical values of urban areas. Potential sources of such elements are the urban and industrial emissions from the States of Rio de Janeiro and/or São Paulo.     

A genomewide association mapping study using ultrasound‐scanned information identifies potential genomic regions and candidate genes affecting carcass traits in Nellore cattle

The aim of this study was to identify candidate genes and genomic regions associated with ultrasound‐derived measurements of the rib‐eye area (REA), backfat thickness (BFT) and rumpfat thickness (RFT) in Nellore cattle. Data from 640 Nellore steers and young bulls with genotypes for 290 863 single nucleotide polymorphisms (SNPs) were used for genomewide association mapping. Significant SNP associations were explored to find possible candidate genes related to physiological processes. Several of the significant markers detected were mapped onto functional candidate genes including ARFGAP3, CLSTN2 and DPYD for REA; OSBPL3 and SUDS3 for BFT; and RARRES1 and VEPH1 for RFT. The physiological pathway related to lipid metabolism (CLSTN2, OSBPL3, RARRES1 and VEPH1) was identified. The significant markers within previously reported QTLs reinforce the importance of the genomic regions, and the other loci offer candidate genes that have not been related to carcass traits in previous investigations.