Assessing the impact of understory vegetation cut on soil epigeic macrofauna from a cork-oak Montado in South Portugal

Cork oak “Montados” are a particular Mediterranean ecosystem, which can be found in Southern Portugal. Portuguese “Montados” are man-made ecosystems, mainly used for cork production and cattle farming, that support a high biological diversity. Current sustainable management techniques imply a shrub clearing with heavy machinery, which can be highly disruptive for soil biota. In order to evaluate the effects of understory vegetation management on soil epigeic macrofauna, five zones were defined along a chronosequence of shrub clearing: a non-disturbed zone (zone 5) and zones where understory vegetation was cut at 4–5 years (zone 4), at 3–4 years (zone 3), at 2 years (zone 2) and at 1 year (zone 1). A sixth zone (zone 6) was selected in a pasture, where cattle are occasionally present. Soil fauna was sampled using “pitfall” traps and sampling took place in autumn 2003. A total of 2,677 individuals, separated into 152 species and morphospecies, were caught in the traps. With the exception of zone 6, that presented a lower number of species, all the other zones from the chronosequence presented, in most cases, a similar number of taxa, species diversity (Shannon) and species richness (Margalef). Multivariate analysis separated recently disturbed zones (plus zone 6) from those intervened at longer time; groups like Formicidae, Scydmaenidae, most families from Araneae and insect larvae appeared closely associated to zones 3–5 (with a higher shrub cover and thick litter layers), whereas, other Hymenoptera, Gastropda and most Coleoptera families, appeared associated to recently disturbed zones (zones 1 and 2) and to zone 6, characterized by a lower shrub cover and a lower accumulation of litter. This separation indicates that effects of the intervention can endure for 2 or 3 years. After that time, the normal natural regeneration of the understory vegetation seems to support the restoration of the macrofauna community, thus indicating that the sustainable management strategy adopted, i.e., making a shrub cut every 5–6 years, seems not induce a significant effect on local species richness of soil epigeic macrofauna.     

High K+ supply avoids Na+ toxicity and improves photosynthesis by allowing favorable K+ : Na+ ratios through the inhibition of Na+ uptake and transport to the shoots of Jatropha curcas plants

This study assessed the relationships between external K⁺ supply and K⁺ : Na⁺ ratios associated with Na⁺ toxicity in Jatropha curcas. Plants were exposed to increasing external K⁺ concentrations (6.25, 12.5, 25, 37.5, and 50 mM), combined with 50 mM NaCl in a nutrient solution. Photosynthesis progressively increased as the external K⁺ : Na⁺ ratios increased up to 0.75. The increase of photosynthesis and plant dry matter correlated positively with K⁺ : Na⁺ in xylem and leaves. The transport rates of K⁺ and Na⁺ from roots to xylem and leaves were inversely correlated. These ions presented an antagonistic pattern of accumulation in all organs. Maximum rates of photosynthesis and plant growth occurred with leaf K⁺ : Na⁺ ratios that ranged from 1.0 to 2.0, indicating that this parameter in leaves might be a good indicator for a favorable K⁺ homeostasis under salinity conditions. The higher K⁺ affinity and selectivity compared with Na⁺ in all organs associated with higher xylem flux and transport to shoots are essential for maintaining adequate K⁺ : Na⁺ ratios at the whole‐plant level. These characteristics, combined with adequate K⁺ concentrations, allow J. curcas to sustain high rates of photosynthesis and growth even under toxic NaCl levels.     

Commercial spray-dried porcine plasma does not transmit porcine circovirus type 2 in weaned pigs challenged with porcine reproductive and respiratory syndrome virus

The objective of this study was to evaluate if spray dried porcine plasma (SDPP) containing porcine circovirus type 2 (PCV2) genome supplemented in feed could transmit PCV2 to pigs challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Twenty-three PRRSV-free pigs, non-viraemic for PCV2, were housed in bio-safety level 3 facilities and assigned to four groups in a 2×2 factorial design consisting of PRRSV challenge and a negative control. The diet contained 0 or 8kg SDPP per 100kg of feed. PRRSV challenge groups were inoculated intranasally with 2mL of a suspension containing 10(6) TCID(50)/mL PRRSV. The SDPP used in the study contained 7.56×10(5) PCV2 genome copies per gram. Dietary treatments were fed from 4days prior to PRRSV inoculation until 28days post-inoculation (PI). All challenged pigs developed PRRSV viraemia by day 3PI and PRRSV antibodies were detected in sera by day 14PI, with no difference between diet treatments. Neither PRRSV viraemia nor seroconversion was observed in non-challenged pigs. PCV2 was not detected in the serum of any pigs throughout the experimental period. SDPP containing the PCV2 genome supplemented in feed did not result in PCV2 transmission to either healthy or PRRSV-infected pigs under these experimental conditions.     

免疫抑制是断奶后多系统消耗性综合征的一个特征

研究表明,Ⅱ型猪圆环病毒(PCV2)与许多病症有关,它们统称为猪圆环病毒病(PCVD)。在这些疾病中,在经济上最重要的是断奶后多系统消耗性综合征(PMWS),由于该病能直接引起死亡以及显著提高不可上市猪的比例,所以可造成严重的经济损失(Segales和Domingo,2002)。若干证据表明,免疫抑     

Warming of the Eurasian landmass is making the Arabian Sea more productive

The recent trend of declining winter and spring snow cover over Eurasia is causing a land-ocean thermal gradient that is particularly favorable to stronger southwest (summer) monsoon winds. Since 1997, sea surface winds have been strengthening over the western Arabian Sea. This escalation in the intensity of summer monsoon winds, accompanied by enhanced upwelling and an increase of more than 350% in average summertime phytoplankton biomass along the coast and over 300% offshore, raises the possibility that the current warming trend of the Eurasian landmass is making the Arabian Sea more productive.     

The evolution of agriculture in ants

Cultivation of fungi for food by fungus-growing ants (Attini: Formicidae) originated about 50 million years ago. The subsequent evolutionary history of this agricultural symbiosis was inferred from phylogenetic and population-genetic patterns of 553 cultivars isolated from gardens of "primitive" fungus-growing ants. These patterns indicate that fungus-growing ants succeeded at domesticating multiple cultivars, that the ants are capable of switching to novel cultivars, that single ant species farm a diversity of cultivars, and that cultivars are shared occasionally between distantly related ant species, probably by lateral transfer between ant colonies.     

Long Chain Fatty Acids of Diet as Factors Influencing Reproduction in Cattle

Cattle are fed moderate amounts of long chain fatty acids (FA) with the objective to enhance lactation and growth; however, recent interest on lipid feeding to cows has focused on reproduction, immunity and health. Increasing the caloric density of the ration by fat feeding has generally improved measures of cow reproduction, but when milk yield and body weight losses were increased by fat supplementation, positive effects on reproduction were not always observed. Feeding fat has influenced reproduction by altering the size of the dominant follicle, hastening the interval to first postpartum ovulation in beef cows, increasing progesterone concentrations during the luteal phase of the oestrous cycle, modulating uterine prostaglandin (PG) synthesis, and improving oocyte and embryo quality and developmental competence. Some of these effects were altered by the type of FA fed. The polyunsaturated FA of the n-6 and n-3 families seem to have the most remarkable effects on reproductive responses of cattle, but it is not completely clear whether these effects are mediated only by them or by other potential intermediates produced during rumen biohydrogenation. Generally, feeding fat sources rich in n-6 FA during late gestation and early lactation enhanced follicle growth, uterine PG secretion, embryo quality and pregnancy in cows. Similarly, feeding n-3 FA during lactation suppressed uterine PG release, and improved embryo quality and maintenance of pregnancy. Future research ought to focus on methods to improve the delivery of specific FA and adequately powered studies should be designed to critically evaluate their effects on establishment and maintenance of pregnancy in cattle.     

Serum acute phase proteins as biomarkers of pleuritis and cranio-ventral pulmonary consolidation in slaughter-aged pigs

The purpose of this study was to investigate the relationship between the existence of lung lesions in pigs at slaughter and the concentration of the serum acute phase proteins (APP), haptoglobin (Hp), pig-major acute protein (Pig-MAP) and C-reactive protein (CRP). A total of 24 pig farms were selected out of a larger farm database previously screened to study risk factors associated with pleuritis and cranio-ventral pulmonary consolidation (CVPC) lesions at slaughter-aged pigs in Spain. The farms were classified as “pleuritis negative (P−) or positive (P+)” and as “CVPC negative (M−) or positive (M+)” and divided into four groups according to a 2X2 factorial design (P−M−, P−M+, P+M−, P+M+). Also at slaughter, blood from 20 randomly selected pigs from each farm was collected. Obtained serum samples were used to measure acute phase proteins. All APP concentrations were significantly higher for M+ farms than for M− ones. However, only Hp and Pig-MAP showed significantly higher concentrations for P+ farms than for P− ones. Pig-MAP was the most sensitive biomarker since it was able to clearly discriminate between P−/P+ and M−/M+ groups (p < 0.001 in both cases). Hp was an excellent marker for pleuritis and good for CVPC lesions. CRP was able to discriminate for CVPC lesions but not for pleuritis. The present results indicate that Pig-MAP and, possibly Hp, may be used as potential markers to characterise and discriminate respiratory lesions in swine herds at slaughter.