Spatio-temporal dynamics of gross rainfall partitioning and nutrient fluxes in shaded-cocoa (<Emphasis Type="Italic">Theobroma cocoa</Emphasis>) systems in a tropical semi-deciduous forest

Land-use change from forest to cocoa agroforestry and other tree-based farming systems alters the structure of forest stands and influences the magnitude of canopy water fluxes and subsequent bio-element inputs to the forest floor. The partitioning of incident rainfall (IR) into throughfall (TF), stemflow (SF) and canopy interception loss (IL_C) and their associated nutrient element concentrations and fluxes was examined along a replicated chrono-sequence: forest, 3, 15 and 30-year-old smallholder shaded-cocoa systems in Ashanti Region, Ghana. Mean annual precipitation during the 2-year observational period (2007 and 2008) was 1376.2 ± 93.8 mm. TF contributed between 76.5–90.4%, and SF between 1.4–1.7% of the annual IR to the forest floor. There were significant differences in IR, TF and SF chemistry. While TF and SF were enriched in phosphorus (1.33–5.67-fold), potassium (1.1–5.69 fold), calcium (1.35–2.65 fold) and magnesium (1.4–2.68 fold) relative to IR, total N (NH₄ ⁺+NO₃ ^?) declined (0.5–0.91) of IR values in TF and SF in forest and shaded cocoa systems. Incident rainfall was significantly more acidic than TF and SF in both forest and shaded-cocoa systems. Mean annual total N, P, K, Ca and Mg inputs to the forest floor through IR were 5.7, 0.14, 13.6, 9.43 and 5.6 kg ha^?1year^?1 respectively. Though an important source of available nutrients for plant growth, incident rainfall provides only a small percentage of the annual nutrient requirements. With declining soil fertility and pervasive low cocoa yields, possible effects of the reported nutrient fluxes on nutrient budgets in cocoa systems merit further investigation. Against the background of increased TF and decreased IL_C following forest conversion to shaded-cocoa, it is also recommended that more studies be carried out on rainfall partitioning and its impact on ground water recharge as a way of establishing its influence on the availability of moisture for agriculture in these systems.     

Evaluation of competition and light estimation indices for predicting diameter growth in mature boreal mixed forests

A series of conventional distance-independent and distance-dependent competition indices, a highly flexible distance-dependent crowding index, and two light resource estimation indices were compared to predict individual tree diameter growth of five species of mature trees from natural-origin boreal mixed forests. The crowding index was the superior index for most species and ecosites. However, distance-independent indices, such as basal area of competing trees, were also effective. Distance-dependent light estimation indices, which estimate the fraction of seasonal photosynthetically-active radiation available to each tree, ranked intermediate to low. Determining separate competition indices for each competitor species accounted for more variation than ignoring species or classifying by ecological groups. Species’ competitive ability ranked (most competitive to least): paper birch ≈ white spruce ≈> trembling aspen > lodgepole pine > balsam poplar. Stratification by ecosite further improved model performance. However, the overall impact of competition on mature trees in these forests appears to be small.     

Reproductive characteristics of the fishery important temperate demersal berycid Centroberyx gerrardi indicate greater reproductive output in regions of upwelling

The reproductive biology of Centroberyx gerrardi (Günther) was investigated across ~2,000 km of its southern Australian distribution, encompassing different jurisdictions and varying environmental features. Greater gonad mass and prevalence of spawning fish, along with lower ratios of lengths at maturity:maximum lengths and ages at maturity:maximum ages, were identified at the western‐most (Capes) and eastern‐most (Great Australian Bight; GAB) regions. Across the study region, spawning peaks in summer/autumn, when water temperatures are warmest. Regional differences in potential “reproductive output,” while not consistent with the eastward decline in mean monthly water temperature, may instead be related to summer upwelling in the Capes and GAB, driving greater oceanic productivity prior to peak spawning, supporting larval survival. In autumn, the prevailing southward and eastward flowing, downwelling Leeuwin Current (LC) strengthens, providing a dispersal mechanism along the west and south Australian coasts, but limiting upwelling effects. Predicted changes in environmental conditions and their potential impacts on C. gerrardi are discussed, in particular how these factors may affect recruitment to stocks and fisheries, requiring a better understanding of source‐sink relationships for this species. As environmental changes occur, management strategies to sustain fish resources must adapt to spatially variable and changing reproductive output and be collaborative across jurisdictions.     

Prevalence and risk factors of mycobacterial infections in farm and trade cattle in southwestern Nigeria

We evaluated the prevalence of mycobacterial infections (i.e., Mycobacterium bovis and non-tuberculous mycobacteria [NTM]) and their associated risk factors among cattle herds and trade cattle in southwestern Nigeria. Through cross-sectional study design, cattle herds from three locations were screened using the single intradermal comparative cervical tuberculin test based on two diagnostic standards; more than 4 mm (? 4 mm) and more than 2 mm (? 2 mm) cut-off points. Abattoir study involved screening trade cattle for tuberculous lesions. Overall, 515 cattle from 45 herds were screened. Using >?4 mm, animal level and herd prevalence of 11.7 and 46.7% were recorded, respectively. Applying the ? 2 mm cut-off, animal level and herd prevalence increased to 31.1 and 60.0%, respectively. Significantly, using the ? 2 mm cut-off, cattle in medium size herds/extensive management system (OR?=?1.6; 95% CI 1.1–2.5) and Sokoto Gudali (OR?=?2.3; 95% CI 1.4–3.8) were more at risk of being positive reactors, while Rahaji (OR?=?0.3; 95% CI 0.1–0.7) breeds of cattle and cows in the peri-urban area (OR?=?0.4; 95% CI 0.2–0.9) were less at risk of being positive reactors. Again, M. avium reactor of 21.7% was observed. In the abattoir, 1797 cattle were examined with 126 lesions suggestive of tuberculosis (TB). Culture/molecular analyses confirmed 2.2% M. bovis and 0.9% NTM infections. Risk factors associated with bovine TB among trade cattle were sex (OR?=?4.0; 95% CI 1.2–13.5) and age (OR?=?0.3; 95% CI 0.1–0.9). We confirm 11.7% prevalence of mycobacterial infections among populations of cattle screened with breed and herd size being major risk factors.     

Sperm production and quality in European eel (Anguilla anguilla) in relation to hormonal treatment

Aquaculture production relies on controlled management of gametogenesis, especially in species where assisted reproduction is needed for obtaining gametes in captivity. The present study used human chorionic gonadotropin (hCG) treatments to induce and sustain spermatogenesis in European eel (Anguilla anguilla). The aim was to evaluate effects of strip-spawning timing (12 vs. 24 hr) after weekly administration of hCG and the necessity of a primer dose (in addition to weekly hormonal treatment) prior to strip spawning (primer vs. no-primer) on sperm quality parameters. Sperm parameters included milt production (weight), density and sperm kinematics at Week 9, 11 and 13 after onset of treatment. Spermiation commenced in 11.5% of males in Week 5 and by Week 9, and all males produced milt. Male weight, milt production, sperm density and spermatocrit did not differ among hormonal treatments during the experimental period. Overall, male weight decreased from 106.3 to 93.0 g, milt weight increased from 3.5 to 5.4 g, sperm density counts decreased from 11.7 × 10⁹ to 10.5 × 10⁹ cells/ml, and spermatocrit decreased from 46.5% to 40.5%. Furthermore, spermatocrit was positively related to haemocytometer counts (R² = .86, p < .001), providing a reliable indicator of sperm density. Differences in sperm kinematics were observed depending on strip-spawning timing after hormonal injection (12 vs. 24 hr) but with no consistent pattern. These sperm quality parameters also did not consistently differ between the no-primer and primer treatments. Considering that each male may be stripped 4–5 times over the 2–3 months spawning season, omitting the primer would reduce animal handling, material costs and labour intensity, while sustaining high-quality sperm production.     

Wheat Grain Hardness Among Chromosome 5D Homozygous Recombinant Substitution Lines Using Different Methods of Measurement

The level of grain hardness of wheat (Triticum aestivum) cultivars profoundly affects milling properties and end-use. We examined grain hardness among a genetically defined set of 83 chromosome 5D homozygous recombinant substitution lines derived from soft wheat cv. Chinese Spring and hard wheat cv. Cheyenne and compared four common methods of measuring wheat grain hardness. Measures of grain hardness included a modified particle size index, Brabender Quadrumat flour milling, near-infrared reflectance (NIR) spectroscopy, and the single-kernel characterization system (SKCS). Duncan's multiple range test was used to group recombinant lines according to parental classes. Quadrumat milling fractions, percent bran and middlings, were well correlated to NIR and SKCS grain hardness, whereas break flour, a traditional measure of grain hardness, was poorly correlated to other hardness measures. NIR and SKCS grain hardness measures provided the greatest and similar mean separations. Both methods identified recombinant lines as being significantly outside either parental class and significantly different from and in between the two parental classes. Between two divergent environments, correlations (r) for Quadrumat bran and middlings percents and NIR and SKCS hardness ranged from 0.83 to 0.94. Analysis of variance indicated that lines differed substantially for hardness, and hardness was highly influenced by environment, albeit consistently, as indicated by low line-location model interaction terms. The results confirmed the presence of major allelic differences assignable to chromosome 5D and suggested the action of minor gene(s). Break flour, in particular, showed strong indications of transgressive segregation independent of the Hardness (Ha) locus. The Perten 4100 SKCS provided the best (most discriminating) measure of the material properties of the wheat endosperm manifested by the action of the Ha locus.     

Using mixed methods to investigate factors influencing reporting of livestock diseases: A case study among smallholders in Bolivia

Livestock disease surveillance is particularly challenging in resource-scarce settings, where disease events are often unreported. Surveillance performance is determined as much by the quantifiable biological attributes of the disease, as it is by motivations and barriers perceived by livestock keepers for disease reporting. Mixed methods designs, which integrate the collection, analysis and interpretation of qualitative and quantitative data in a single study, are increasingly used across different disciplines. These designs allow for a deeper exploration of the topic under investigation, than can be achieved by either approach alone.     

Canine renal pathology associated with grape or raisin ingestion: 10 cases.

Ten dogs suffered acute renal failure after ingesting > or = 3 g/kg (dry matter) of grapes or raisins. All dogs had degeneration or necrosis (or both) of proximal renal tubules with basement membranes remaining intact, and epithelial regeneration was observed in 5 out of 10 cases. Mineralized tubular debris or granular to proteinaceous casts (or both) were present in all cases. A golden-brown, globular, intracellular pigment of varying amounts and sizes was observed in 6 out of 10 cases with variable reaction with Prussian blue. Multifocal fibrinous arteritis of the large colon was seen in 2 out of 5 cases with globulin insudation of vessel wall demonstrated by immunohistochemical staining for immunoglobulin (Ig)G and IgM. Mineral analysis on frozen renal tissue from 2 out of 2 cases revealed mildly elevated Ca:P ratio in both. Clinically significant observations were preservation of the integrity of basement membranes after grape-induced tubular injury and presence of early epithelial regeneration. Thus, recovery may be possible if anuria is aggressively managed. With respect to potential pathophysiologic mechanisms, further research into the roles of calcium homeostasis, vascular reactivity, and the significance of the golden-brown pigment is indicated.     

Regulation of blood and lymphatic vascular separation by signaling proteins SLP-76 and Syk

Lymphatic vessels develop from specialized endothelial cells in preexisting blood vessels, but the molecular signals that regulate this separation are unknown. Here we identify a failure to separate emerging lymphatic vessels from blood vessels in mice lacking the hematopoietic signaling protein SLP-76 or Syk. Blood-lymphatic connections lead to embryonic hemorrhage and arteriovenous shunting. Expression of slp-76 could not be detected in endothelial cells, and blood-filled lymphatics also arose in wild-type mice reconstituted with SLP-76-deficient bone marrow. These studies reveal a hematopoietic signaling pathway required for separation of the two major vascular networks in mammals.     

Partial substitution of fish meal with soybean and cottonseed meals in diets for African bonytongue,Heterotis niloticus (Cuvier, 1829) fingerlings: effects on growth,feed efficiency and body composition

A feeding trial was conducted to examine the suitability of soybean meal (SBM) and cottonseed meal (CSM) as a partial substitute for the dietary protein supplied by fish meal for H. niloticus fingerlings. Fish were fed with four isonitrogenous (350 g kg^?1 crude protein) and isoenergetic (18.8 kJ g^?1 GE) diets in which fish meal protein was gradually replaced by plant protein from a mixture of SBM and CSM (0%, 25%, 50% and 75% in diets 1, 2, 3 and 4 respectively). Triplicate groups of fingerlings H. niloticus (mean weight of 5 g) were handfed twice daily to apparent satiation for 60 days inside net hapas. Growth performances (SGR varied from 3.09% to 3.16% day^?1) of fingerlings fed diets containing 0%, 25% and 50% plant protein were not significantly different (P>0.05). At 75% fish meal substitution, growth and feed utilization efficiency indicators were significantly reduced (P<0.05). The carcass composition were also significantly (P<0.05) affected by the replacement level of fish meal, except dry matter and ash. Results suggest that the dietary fish meal protein could efficiently be substituted by a mixture of soybean and cottonseed meals up to 50%, without adverse effects on maximal growth in practical diets for H. niloticus fingerlings.