Prevalence pattern and biology of Sarcocystis capracanis infection in the Egyptian goats: a light and ultrastructural study

Cysts of Sarcocystis capracanis obtained from infected goats were examined to clarify the effect of the parasite on the host. Muscle tissues from fresh oesophagus, tongue, diaphragm and skeletal muscles of 680 goats were slaughtered in the main abattoir of Cairo, Egypt and they were examined microscopically for Sarcocystis infection for the first time in Egypt. 540 out of 680 (79.4%) of examined goats were found to be infected with Sarcocystis sp. The infection was recorded firstly by light microscopy as spindle shaped cysts embedded in the muscle tissues. The validity of this species as S. capracanis was confirmed by means of ultrastructural characteristics of the primary cyst wall which revealed the presence of thick-radially striated wall with finger like projections, underlined by a thick layer of ground substance enclosing the developing metrocytes and merozoites that usually contain nearly all the structures of the apical complex and fill the interior cavity of the cyst. The cyst cavity is divided by many septa extending from the ground substance and producing large number of chambers. An experimental infection using the highly infected muscles was carried out to determine the final host, which is dog. Smears of intestinal epithelium were taken to examine the endogenous stages (gamogony and sporogony) by means of light microscopy. These stages were mainly observed as to infect the lamina propria of the posterior third of the small intestine. Gamogony and zygote formation (fertilization) occurred 2-8 days post infection, while sporulation took place within the final host 13-15 days and sporocysts were passed within faeces of the infected puppies at that time. The prepatent period of S. capracanis was 12-15 days, while the patent period was extended to 37 days. In goats, infection with S. capracanis led to the loss of weight, anaemia, abortion and even death in cases of heavy infection. While bleeding, watery faeces filled with mucous on 5th and 8th day p.i. as well as intestinal lesions are the pathogenic effects occurred in puppies after experimental infection.     

Contribution of different rumen microbial groups to gas,short‐chain fatty acid and ammonium production from different diets—an approach in an in vitro fermentation system

In this study, the relative contribution of different microbial groups to ruminal metabolism was investigated for different diets. The rumen microbial cultures included whole rumen fluid, fungi + protozoa, bacteria + protozoa, protozoa and bacteria + fungi and were established by physical and chemical methods. Gas production, short‐chain fatty acid (SCFA) and ammonium production were measured at 24 hr in in vitro incubations using the Hohenheim gas test (HGT) procedure. Seven donor animal diets with different concentrate‐to‐roughage ratios (C:R: 10:90, 30:70, 50:50, 70:30, 70:30BC (BC = NaHCO₃), 90:10 and 90:10BC) and five HGT diets (C:R: 10:90, 30:70, 50:50, 70:30 and 90:10) were formulated. Incubations in the HGT were always based on inoculum from sheep diets with the respective C:R ratio. Gas and ammonium production increased (p < 0.001) as a result of a gradual increase in concentrate proportion of the diets. In general, SCFA production followed the same trend. Whole rumen fluid and bacteria + fungi produced approximately 50% higher gas volume than protozoa and fungi + protozoa fractions, whereas gas production with bacteria + protozoa was at an intermediate level. Coculture of protozoa either with bacteria or with fungi produced more ammonium. Populations without bacteria were characterized by a particularly high acetate/propionate ratio. Although an interaction between microbial group and diet was observed for several variables, no clear direction could be established. Manipulating rumen fluid by selectively suppressing specific rumen microbial groups may be a helpful tool in elucidating their role in nutrient degradation and turnover in vitro.     

Composting of Wood Containing Polycyclic Aromatic Hydrocarbons (PAHs)

The addition of various nitrogen sources, such as liquid hog manure and mineral medium, to pine wood accelerated the composting process in Dewar vessels, which was obvious from the increased decomposition temperature and the more intensive oxygen consumption and carbon dioxide production. During composting in Dewar vessels of artificially PAH-contaminated pine wood soaked with liquid manure, the PAH degradation was influenced by the inoculum used. The fastest PAH degradation was achieved by compost addition, but the most intensive carbon dioxide evolution was measured with hydrocarbon-polluted soil as an additive. After 61 days, the PAH content of the wood was reduced from each 1000 mg/kg to 26 mg/kg of phenanthrene and 83 mg/kg of pyrene. The relation between the microbial wood decay and PAH degradation shows that the detoxification at least of artificially PAH-polluted wood demands only a partial wood decay.

A pilot scale percolator was applied to composting of artificially contaminated pine wood and really polluted waste wood. After 27 days of remediation, the portion of residual PAHs was higher in the case of the really polluted material. The slower degradation in the real waste wood may be explained by the lower bioavailability of pollutants in comparison with the artificially contaminated wood. In really polluted wood, the degradation rate of PAHs depended on their degree of condensation (the higher the number of aromatic rings the smaller the degradation rate was).     

Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) in Waste Wood

PAH-contaminated waste wood is a serious environmental problem. As an alternative to incineration and landfill disposal, wood containing PAHs may be detoxified by composting. The efficiency of this process depends on the composting conditions. The aerobic treatment of PAH-containing wood was therefore investigated under varying environmental conditions with particular attention to the kinetics of PAH degradation and wood mineralization. The composting of pine wood spiked with 2 g/kg phenanthrene, anthracene and pyrene each and subsequently artificially aged was studied on a laboratory-scale using a respiration analyzer. The temperature was found to highly influence both PAH degradation and wood decay. The fastest and most extensive PAH degradation and wood mineralization were found at 30°C. Higher temperatures particularly inhibited the degradation of anthracene and pyrene. The addition of urea markedly accelerated both PAH degradation and wood mineralization. Only small amounts of urea were needed to maximize PAH degradation, whereas higher amounts of urea were required to maximize wood mineralization. Urea hydrolyzes to ammonium carbonate, which in turn forms highly volatile ammonia. When more then 2 g/kg urea-N was added to the wood, excessive nitrogen disappeared as ammonia via the gas phase. Using nitrate instead of urea dramatically reduced both PAH degradation and wood mineralization. Although a slightly alkaline pH seemed to promote PAH degradation, it has to be taken into account that this experiment was carried out with nitrate as an N source rather than urea to avoid any N losses at high pH values. Glucose as a cosubstrate neither accelerated PAH degradation nor stimulated wood decay. Molasses as a cosubstrate actually inhibited PAH degradation since it contains much salt and alkalinized the rot material.     

Prazisionsstufen der Stickstoffdüngungsbemessung zu Winterweizen und Winterroggen auf Sandigen Böden*

In einer Versuchsserie von 1996 bis 1998 wurden auf vier sandigen Standorten Feldversuche mit Winterweizen bzw. Winterroggen durchgeführt. In die Parzellen sind Mikroparzellen für die Düngung mit ¹⁵N‐Tracern installiert worden. Varianten: ungedüngt, halbierte Düngung, 120kgha^?1 ? in 2 bzw. 3 Teilgaben sowie Düngerberechnung über ein EDV‐Programm unter Einbeziehung des N_min‐Gehaltes des Bodens und schließlich zuzüglich der indirekten Messung des Chlorophyllgehaltes der Blätter des Getreides.

Die über Computer. N_min‐Ermittlung und Chlorophyll‐Tester modifizierten N‐Aufwendungen haben zu keiner eindeutigen Ertragsverbesserung geführt. Insgesamt wurden zwischen Ertrag und N_min‐Werte + N‐Düngung enge Beziehungen errechnet. Die Spanne der N‐Entzüge ist von 41 bis 160 kgha^?1 bei Weizen und 48 bis 83 kg ha^?1bei Roggen weit. Der N_min‐Gehalt zum Erntezeitpunkt ist unterschiedlich. Je niedriger die Rest‐N‐Mengen sind, um so mehr verringert sich der prozentuale Anteil des düngerbürtigen ? bzw. die Wiederfindungsrate des eingesetzten Mineraldüngers.     

Soil indicator systems ‐ the basis for soil conservation decisions to control soil erosion and soil compaction

The efficiency and acceptance for erosion and compaction control management is not high and therefore not a guarantee for sustainable land use and soil functionality. The best method for increasing acceptance is a regional soil indicator system combined with an environmental indicator system (McRae et al. 2000). Like the concept of “critical load inputs”; for chemical pollutants, this system would make it possible to quantify the soil state and soil condition for decisions concerning the soil carrying or load capacity. The next step is the assessment of the land use pressure on soil in terms of the soil load capacity and the driving forces for land use. These results may determine the response level required: In a balanced situation, Best Management Practices may help ensure sustainability is maintained, slightly disproportional results suggest additional special agricultural management techniques may be needed, while significant differences may indicate the need for additional land use adjustments or changes in technical management. The indicator system is ideal for application in north‐eastern Germany for all moraine areas and the areas at risk to water and wind erosion and soil compaction.     

Microbially-mediated gross N transfer rates in field soils in relation to physico-chemical transfer processes

Abstract

Measurements of gross N transfer in soils have as yet not distinguished between biological or physico-chemical processes. Here, we present a new approach that allows microbially-mediated gross N transfer rates to be estimated in undisturbed soils without adding ¹⁵N. It is based on the assumption that in undisturbed soil, the soil microbial growth rate is equal to its death rate. To assess the contribution of biological versus physico-chemical N transfer processes, we combined the new approach with the ¹⁵N-pool dilution technique. The relationship between both processes varied with soil C and fine particle contents. Nearly equal rates were observed within the carbon-poor soil (0.35% C_org, low fine particle content), whereas up to 2.5 times higher physico-chemical than biological N transfer rates were measured within the carbon-enriched soil (0.86% C_org, higher fine particle content). Furthermore, microbially-mediated gross N transfer rates increased three-fold after N fertilization compared to the unfertilized control.     

Feeding potential of cassava (Manihot esculenta Crantz) peels ensiled with Leucaena leucocephala and Gliricidia sepium assessed with West African dwarf goats

Cassava peels (CaPe) were ensiled in mixtures with Gliricidia sepium and Leucaena leucocephala, and the utilization of the mixed silages by West African dwarf (WAD) goats was assessed. Five silages were composed, comprising of 100 % ensiled CaPe (control), CaPe?+?G. sepium 2:1 (w/w; 2CGS), CaPe?+?G. sepium 1:1 (w/w; CGS), CaPe?+?L. leucocephala 2:1 (w/w; 2CLL) and CaPe?+?L. leucocephala 1:1 (w/w; CLL). All diets were supplemented with molasses (40 g/kg) before ensiling which lasted 3 months. Fifteen WAD goats (8.01?±?0.12 kg body weight) were fed one of the experimental diets (50 g/kg body weight) for 8 weeks. The control had the lowest hydrocyanic acid content (0.05 mg/kg DM), while others ranged from 6.2 to 81.3 mg/kg. Condensed tannin concentration ranged from 1.7 to 8.4 mg/kg DM, while mimosine levels were 11.6 and 12.4 mg/kg DM in 2CLL and CLL, respectively. After fermentation, all silages showed low pH (<4.5) and were different (P?<?0.05) in the lactic, acetic and butyric acid concentrations. Ratio of foliage supplementation influenced DM intake (P?<?0.05). Daily weight gains ranged from 17 (CLL) to 24 g/day in control. The digestibility coefficients of nutrients and fibre fractions differed (P?<?0.05) among diets. The values for packed cell volume, haemoglobin, red blood cells, neutrophils, lymphocytes and monocytes were also different (P?<?0.05) across the dietary treatments. Ensiling CaPe with foliages of G. sepium and L. leucocephala can be recommended for feeding WAD goats especially during the dry spells when there is little or no available forage for the animals.     

Pachydictyols B and C: New Diterpenes from Dictyota dichotoma Hudson

Two new diterpenoids, pachydictyol B (1a/1b) and C (2), were isolated from the dichloromethane extract of the marine brown alga, Dictyota dichotoma, collected from the Red Sea coast of Egypt, along with the known metabolites, pachydictyol A (3a), dictyol E (4), cis-africanan-1α-ol (5a), fucosterol (6), tetrahydrothiophen-1,1-dioxide and poly-β-hydroxybutyric acid. GC-MS analysis of the nonpolar fractions also indicated the presence of β-bourbonene and nonanal, along with three hydrocarbons and five fatty acids or their simple derivatives, respectively. GC-MS analysis of the unsaponifiable algal petroleum ether extract revealed the presence of a further eight compounds, among them 2,2,6,7-tetramethyl-10-oxatricyclo[4.3.0.1(1,7)]decan-5-one (7), N-(4-bromo-n-butyl)-piperidin-2-one (8) and tert-hexadecanethiol. Structures 1–6 were assigned by 1D and 2D NMR, mass spectra (EI, CI, HREI and HRESI) and by comparison with data from related structures. The crude algal extract was potently active against the breast carcinoma tumor cell line, MCF7 (IC₅₀ = 0.6 µg mL⁻¹); pachydictyol B (1a) and dictyol E (4) showed weak antimicrobial properties, and the other compounds were inactive. Pachydictyols B (1a) and C (2) demonstrated a weak and unselective cytotoxicity against twelve human tumor cell lines with a mean IC₅₀ of >30.0 µM.