Polyphenols in the woody roots of Norway spruce and European beech reduce TTC

A common method to determine the vitality of fine root tissue is the measurement of respiratory activity with triphenyltetrazolium chloride (TTC). The colorless TTC is reduced to the red-colored triphenyl formazan (TF) as a result of the dehydrogenase activity of the mitochondrial respiratory chain. However, measurements with woody fine roots of adult Norway spruce and European beech trees showed that dead control roots had a high potential to react with TTC. High reactivity was found in boiled fine roots and the bark of coarse roots, but not in the boiled wood of coarse roots. By sequential extraction of dried and ground adult Norway spruce fine roots, reactivity with TTC was reduced by about 75% (water extraction), 93% (water/methanol extraction) and 94% (water/acetone extraction). The water extract reacted with TTC in the same way as polyphenols such as lignin, catechin and epicatechin. Boiling did not affect the extent to which fine roots of adult trees reduced TTC, whereas it greatly reduced TTC reduction by seedling roots. Application of the TTC test to roots of spruce seedlings subjected to increasing drought showed a progressive decrease in TTC reduction. The decrease in TTC reduction was paralleled by a reduction in O(2) consumption, thus supporting the conclusion that for roots with a low polyphenol content the TTC test provides a valid assessment of tissue vitality. Our results suggest, however, that the TTC test should not be applied to the fine roots of adult trees because of their high content of polyphenolic compounds whose reaction with TTC masks changes in TTC reduction due to changes in the respiratory capacity of the tissue.     

Improving regeneration of mahogany: techniques for vegetative propagation of four African mahogany species using leafy stem cuttings

Regeneration to ensure sustainable production and conservation of mahogany species globally is considered very important to foresters, investors in plantation, conservationists and timber industries worldwide. Natural regeneration of the mahoganies has been found to be far less than the rate of exploitation hence strong efforts are being made to develop other methods to regenerate mahogany seedlings to augment the low natural replacement and to ensure sustainability. This study was commissioned to investigate the effect of rooting media (river-sand, top soil and a mix of the two (50:50 v/v) on the rooting ability of four mahogany species (Khaya grandifoliola, K. ivorensis, Entandrophragma angolense and E. utile) using non-mist propagators. We investigated the effects of the source of stem cutting within a shoot (top, middle and basal position) on the rooting ability of stem cuttings from the four species in river-sand. Roots per cutting, longest root length and rooting percentage differed significantly among species in all three rooting media. Rooting ability was greatest in K. grandifoliola, which exhibited the highest average rooting percentage (73 %), longest average single root (9.9 mm) and the most roots per cutting (4.9). Rooting percentage was higher in the Khaya species than in the Entandrophragma species in all three rooting media. The mixed medium had the highest rooting percentage and the highest number of roots per rooted cutting in the two Khaya species, while the topsoil media had the best rooting percentage in the Entandrophragma species. Rooting of the two Khaya species can be maximized using a mixture of river-sand and topsoil. Cutting position within a shoot had significant impact on rooting in all four species with rooting percentage being best from middle positions in all four species. However, length of longest root and the number of roots per rooted cutting varied between the middle and basal portions. The study provides useful information for vegetative propagation of leafy stem cutting of the four African mahogany species, which could contribute to regeneration and conservation of these important timber species in the tropics.     

Comparative Utilization of Different Fibre Feedstuffs by Weaning/Growing Pigs in the Tropics

This study was conducted to investigate the effect of feeding different fibre feedstuffs on the performance, nutrient utilization and economics of production of weaning/growing pigs. Five fibre feedstuffs--palm kernel cake （PKC）, wheat offal （WO）, corn bran （CB）, rice bran （RB） and brewers＇ dried grain （BDG） were used at 25% in each of the five experimental diets that were formulated in this study. Twenty weaner pigs （12.75 ± 0.6 kg） were used for the growth study while 15 pigs （14.95 ± 0.57 kg） were used for the digestibility study. The design of the experiment was completely randomized. The results of the study showed that the performance of the experimental animals were significantly influenced （P 〈 0.05） by the dietary treatments. The apparent digestibility of the crude protein, crude fiber and ether extract showed significant differences （P 〈 0.05） while there was no significant difference （P 〉 0.05） in the apparent digestibility of their dry matter, ash and nitrogen free extract. The diet that contained WO had the best growth response and apparent nutrient digestibility. Results of economics of production also showed that diet with WO gave the best （P 〈 0.05） value in feed cost/＇kg gain and net profit/animal. It can be concluded from this study that although all the animals fed the different fibre feedstuffs performed satisfactorily on all the parameters monitored, but for optimum growth, apparent nutrients digestibility and economics of production. WO should be used as a fibre feedstuff in the diets of weaning/growing pigs in the tropics.     

Management of a caseous lymphadenitis outbreak in a new Iberian ibex (Capra pyrenaica) stock reservoir

Background

In 2010, an Iberian ibex (Capra pyrenaica hispanica) stock reservoir was established for conservation purposes in north-eastern Spain. Eighteen ibexes were captured in the wild and housed in a 17 hectare enclosure. Once in captivity, a caseous lymphadenitis (CLA) outbreak occurred and ibex handlings were carried out at six-month intervals between 2010 and 2013 to perform health examinations and sampling. Treatment with a bacterin-based autovaccine and penicillin G benzatine was added during the third and subsequent handlings, when infection by Corynebacterium pseudotuberculosis was confirmed. Changes in lesion score, serum anti-C. pseudotuberculosis antibodies and haematological parameters were analyzed to assess captivity effects, disease emergence and treatment efficacy. Serum acute phase proteins (APP) Haptoglobin (Hp), Amyloid A (SAA) and Acid Soluble Glycoprotein (ASG) concentrations were also determined to evaluate their usefulness as indicators of clinical status.Once in captivity, 12 out of 14 ibexes (85.7%) seroconverted, preceding the emergence of clinical signs; moreover, TP, WBC, eosinophil and platelet cell counts increased while monocyte and basophil cell counts decreased. After treatment, casualties and fistulas disappeared and both packed cell volume (PCV) and haemoglobin concentration significantly increased. Hp, SAA and ASG values were under the limit of detection or showed no significant differences.

Conclusions

A role for captivity in contagion rate is suggested by the increase in antibody levels against C. pseudotuberculosis and the emergence of clinical signs. Although boosted by captivity, this is the first report of an outbreak of caseous lymphadenitis displaying high morbidity and mortality in wild ungulates. Treatment consisting of both vaccination and antibiotic therapy seemed to prevent mortality and alleviate disease severity, but was not reflected in the humoural response. Haematology and APP were not useful indicators in our study, perhaps due to the sampling frequency. Presumably endemic and irrelevant in the wild, this common disease of domestic small ruminants is complicating conservation efforts for the Iberian ibex in north-eastern Spain.     

The emergence of Schmallenberg virus across Culicoides communities and ecosystems in Europe

Schmallenberg virus (SBV), a novel arboviral pathogen, has emerged and spread across Europe since 2011 inflicting congenital deformities in the offspring of infected adult ruminants. Several species of Culicoides biting midges (Diptera: Ceratopogonidae) have been implicated in the transmission of SBV through studies conducted in northern Europe. In this study Culicoides from SBV outbreak areas of mainland France and Italy (Sardinia) were screened for viral RNA. The role of both C. obsoletus and the Obsoletus complex (C. obsoletus and C. scoticus) in transmission of SBV were confirmed in France and SBV was also discovered in a pool of C. nubeculosus for the first time, implicating this species as a potential vector. While collections in Sardinia were dominated by C. imicola, only relatively small quantities of SBV RNA were detected in pools of this species and conclusive evidence of its potential role in transmission is required.     

The value of bushmeat and other wild foods to rural households living in extreme poverty in Democratic Republic of Congo

We examine the relationship between poverty and the use of wild foods, namely bushmeat, fish and wild plants, within a Congolese agricultural community. A sample of 121 households were monitored over a 16-month period, using a combination of participatory and quantitative survey techniques, to assess their wealth and their production, consumption and market sales of wild foods. Households varied in wealth but all could be considered subject to extreme poverty (income below US$1 per capita per day). Our analyses indicate that wild foods play a small role in household consumption but a major role in household income. Hence, over 90% of both bushmeat and fish production is sold at market. In addition, the value of wild foods increases in the “lean season” when agricultural production is low. We also find that the poorest households in this community are unable to capitalise on the most valuable wild foods, bushmeat and fish, as a source of food or cash income. We use an entitlements framework to explain the factors that determine such wealth-related variation between households, indicating that household use of wild foods is determined more by social and economic constraints than by resource abundance in this community. Nevertheless, our findings show that overall the small-scale commercialisation of wild foods provides a vital source of income for rural households living in extreme poverty.     

Effect of cutting edge thickness and state of wear of ploughshare on draught force and heart rates of Sanga oxen in Ghana

In this study, draught forces and heart rates of oxen were measured during ploughing to assess ploughshare cutting edge performance. The main objective of the study was to examine the effect of cutting edge thickness and state of wear of animal-drawn mouldboard ploughshares on the draught force and the heart rates of oxen pulling the implement and to determine the optimum cutting edge that gives the least draught force and lowest heart rates when pulled by animals. To minimise soil variability, a field was ploughed, harrowed and left to consolidate for 4 weeks before field experiments started. A pair of Sanga oxen was used during the field test. Analyses of variance showed there were significant differences (p < 0.05) in the mean draught forces and the corresponding oxen heart rates for the cutting edges. The field test results indicated the draught forces and heart rates of the animals increased with increasing cutting edge thickness from 2 to 8 mm, but also increased slightly for the 1 mm edge. The draught forces of the other cutting edges relative to the 2 mm were 9%, 1%, 29%, 35% and 65% higher for the 1, 4, 8 mm, Reversed and double-sided, respectively. The heart rates induced by the other cutting edges relative to the 2 mm varied from under 1 to 12%. The draught of the cutting edges was between 6 and 10% of the body weight of the animals used for the experiment. The lowest draught force and heart rate were obtained for the 2 mm cutting edge. Since the 4 mm cutting edge generated draught forces and heart rates values as low as the 2 mm, it was considered potentially more durable under field conditions and could be the recommended cutting edge thickness for animal-drawn shares in similar soil conditions used for the experiment.     

Are ricefields a good alternative to natural marshes for waterbird communities in the Camargue, southern France?

Rice cultivation has frequently been suggested to provide an important wetland habitat for waterbirds. However, in contrast to most other regions of the Mediterranean, the Camargue still has a substantial amount of surface area of natural marshes. Thus, we compared the abundance, species richness, and community composition of waterbirds in ricefields and natural marshes of the Camargue, during a one-year study. Based on surveys conducted at 4–7 day intervals in 1997–1998, our results suggest that natural marshes had substantially greater abundance of waterbirds, with ca. 99% of the individuals having been observed in natural marshes. Estimates of species richness and associated parameters further indicated that ricefields were clearly less rich than natural marshes. Although our results were rather striking for the Camargue, they may not be applicable to other regions because of the relatively high availability of natural marshes and differences in management of ricefields.