Hepatic lipidosis: Liver characteristics and acute phase proteins in affected turkeys

The hepatic lipidosis (HL) in fattening turkeys is a disease has been known for a long time, but the cause and pathogenesis is still not clarified. A recent study reported unexplained high levels of iron in liver tissue of fattening turkeys suffering from HL. In this study, the iron status, possible infectious or inflammatory influences in form of an acute phase reaction and the analysis of fatty acid pattern in liver tissue of turkeys affected by HL were examined. Three cases of HL on three different fattening turkey farms were investigated during the outbreak of the disease. Clinically affected and non-affected animals were subjected to a pathological examination, where the diagnosis HL or non-affected was made. In total, 70 birds were examined (40 with HL, 30 without HL) and blood and liver samples were taken. Additionally, samples from 15 slaughtered birds were taken as a further control group. In liver tissue, the iron content and the content of long-chain fatty acids were determined; in blood samples, ferritin and transferrin were measured. The iron content in liver tissue was more than three times higher for animals with HL than among non-affected animals and the control group. The transferrin levels were lowest for animals with HL, highest in the control group and in between for non-affected animals. The fatty acid pattern in liver tissue of affected animals indicated a shift from polyunsaturated fatty acids to saturated fatty acids and monounsaturated fatty acids compared to the control group and the non-affected animals. Overall, the non-affected animals of a flock affected by HL were similar to the healthy animals of the abattoir. The low acute phase protein levels for animals with HL together with high iron contents could indicate a previous malnutrition/starvation period and/or severe liver damage for those animals suffering from HL.     

Habitat fragmentation in an urban environment: large and small fragments support different arthropod assemblages

We investigated the effects of fragmentation due to urbanisation on the species composition and functional roles of ants, beetles, spiders, flies and wasps. The study was conducted in 21 fragments of heath and woodland in south-eastern Australia classed as either ‘small’ (? 4 km²) or ‘large’ (? 80 km²). Arthropods were pitfall-trapped and identified to family or genus and morphospecies and microhabitat characteristics were recorded. Large fragments did not support more species per unit area than small fragments for most arthropods, although there were more species of ants per sampling unit in small than large woodland fragments, mainly due to a higher frequency of generalist species in smaller fragments. Large and small habitat fragments contained different assemblages of spiders, wasps and ants, indicating that predators and parasitoids are affected more strongly than other trophic groups. Arthropod assemblages within larger fragments where grids were furthest apart were less similar than those within smaller fragments where grids were closer together in woodland, but not in heath. The responses of arthropods to fragmentation suggest that, in addition to effects of reduced area and proximity to the urban matrix, changes in fire regimes and the degradation of habitats resulting from urbanisation, may have a role in altering arthropod assemblages, particularly affecting those species belonging to higher trophic levels. Management goals for urban remnants should identify mechanisms for controlling fire and anthropogenic disturbance such that they closely resemble the levels of these factors in larger fragments.     

Einfluß von SO2 und HF auf freie Aminosäuren der Fichte (Picea abies [L.] Karsten)

The influence of SO₂ and HF on free amino acids of spruce . The influence of the air pollutants SO₂ and HF on composition and amount of free amino acids was investigated. Distinct differences in the pattern of amino acids are caused, particularly in glutaminic acid and compounds based on it.     

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Stomatal conductance, transpiration and sap flow of tropical montane rain forest trees in the southern Ecuadorian Andes

We investigated tree water relations in a lower tropical montane rain forest at 1950-1975 m a.s.l. in southern Ecuador. During two field campaigns, sap flow measurements (Granier-type) were carried out on 16 trees (14 species) differing in size and position within the forest stand. Stomatal conductance (g(s)) and leaf transpiration (E(l)) were measured on five canopy trees and 10 understory plants. Atmospheric coupling of stomatal transpiration was good (decoupling coefficient Omega = 0.25-0.43), but the response of g(s) and E(l) to the atmospheric environment appeared to be weak as a result of the offsetting effects of vapor pressure deficit (VPD) and photosynthetic photon flux (PPF) on g(s). In contrast, sap flow (F) followed these atmospheric parameters more precisely. Daily F depended chiefly on PPF sums, whereas on short time scales, VPD impeded transpiration when it exceeded a value of 1-1.2 kPa. This indicates an upper limit to transpiration in the investigated trees, even when soil water supply was not limiting. Mean g(s) was 165 mmol m(-2) s(-1) for the canopy trees and about 90 mmol m(-2) s(-1) for the understory species, but leaf-to-leaf as well as tree-to-tree variation was large. Considering whole-plant water use, variation in the daily course of F was more pronounced among trees differing in size and crown status than among species. Daily F increased sharply with stem diameter and tree height, and ranged between 80 and 120 kg day(-1) for dominant canopy trees, but was typically well below 10 kg day(-1) for intermediate and suppressed trees of the forest interior.