Effect of Mediterranean saltbush (Atriplex halimus) ensilaging with two developed enzyme cocktails on feed intake,nutrient digestibility and ruminal fermentation in sheep

The aim of this study was to assess the effects of feeding Atriplex halimus (AH) silage treated with two developed enzyme cocktails to sheep on feed intake, nutrient digestibility and ruminal fermentation. The AH silage was treated without or with 2 L of ZAD1^® or ZAD2^®/1000 kg with 5% molasses and ensiled for 30 days. Barley grain (300 g/head/day) was fed as an energy supplement once daily at 10.00 hours and AH silage with or without enzyme treatment was offered ad libitum to animals twice daily at 09.00 and 16.00 hours. Sheep were fed on four experimental forage diets comprised of AH silage and barley (D1), AH silage treated with ZAD1^® and barley (D2), AH silage treated with ZAD2^® and barley (D3) and AH silage treated with a combination of ZAD1^® and ZAD2^® (1:1) and barley (D4). Ensiling AH with enzymes reduced its contents of neutral detergent fiber and acid detergent fiber. The dry matter intake of AH of D2, D3 and D4 decreased (P < 0.001) as compared to D1. However, enzyme‐treated diets had greater total digestible nutrients intake (P < 0.001) as compared to D1. The nutrients digestibility for D2, D3 and D4 were higher than those for D1 (P < 0.001), and were higher for D3 as compared to both D2 and D4. Sheep fed on D3 had highest (P < 0.001) ruminal total volatile fatty acids concentration, ammonia nitrogen concentration and microbial protein yield. It could be concluded that AH silage treated with ZAD1^® or ZAD2^® improved digestibility and rumen fermentation in sheep.     

Effect of increasing levels of seven tree species extracts added to a high concentrate diet on in vitro rumen gas output

This study was conducted to investigate the effects of increasing levels of extracts of Byrsonima crassifolia, Celtis pallida, Enterolobium cyclocarpum, Fraxinus excelsior, Ficus trigonata, Phoradendrom brevifolium and Prunus domestica on in vitro gas production (GP) and ruminal fermentation of a high concentrate diet. Plant extracts were prepared at 1 g dry matter (DM)/8 mL of solvent mixture (methanol : ethanol : water, 1:1:8) and added at levels of 0, 0.6, 1.2 and 1.8 mL/g DM of a high concentrate diet. In vitro GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48 and 72 h of incubation. Increasing addition of extracts linearly increased (P < 0.001), the GP₂₄, GP₄₈ and GP₇₂ (mL/g DM), and linearly decreased (P < 0.001), the discrete GP lag time. Moreover, increasing extract doses linearly increased (P < 0.001) the asymptotic GP and decreased (P < 0.001) the rate of GP. GP₆ was not impacted by treatments and GP₁₂ increased linearly (P = 0.01) with increasing addition of extracts. Rumen pH declined linearly (P < 0.05) with increasing doses of extracts added. As no interactions (P > 0.05) occurred between the extracts and doses, it could be conclude that all extracts positively modified rumen fermentation at doses of 1.2 to 1.8 mL extract/g diet DM.     

Do childhood growth indicators in developing countries cluster? Implications for intervention strategies

OBJECTIVE: The effectiveness of geographic targeting in nutrition programmes depends largely on the degree to which malnutrition clusters within particular areas. This study investigates the extent to which the childhood nutrition indicators, stunting (height-for-age Z-score <-2) and wasting (weight-for-height Z-score <-2), are spatially clustered; this information is used to determine the implications of spatial clustering for the effectiveness of geographic targeting. DESIGN: Analysis of data from Demographic and Health Survey (DHS) results. Clustering is assessed by calculating intra-cluster correlation coefficients (ICCs). Estimating the proportion of malnourished children covered by a programme successfully targeting 10% of clusters with the highest malnutrition prevalences allows an assessment of the effectiveness of geographic targeting. SETTING: Fifty-eight DHS III (1992-1997) and DHS IV (1998-2001) reports from 46 developing countries. SUBJECTS: Pre-school children of mothers interviewed by DHS. MAIN RESULTS: The extent of clustering of nutritional status was surprisingly low (median ICC for national samples: stunting=0.054, wasting=0.032) and most countries were characterised by having an ICC <0.1--i.e. low clustering--for childhood undernutrition (91% of countries for wasting and 78% for stunting). Our assessment of the effectiveness of geographic targeting showed that coverage was better for wasting than for stunting; for wasting, 23% of countries would achieve less than 20% coverage, compared with 76% of countries achieving less than 20% coverage for stunting. Coverage is dependent on the overall prevalence of malnutrition and the ICC. CONCLUSIONS: Childhood nutritional status is determined at the household, or even individual, level; nutrition programmes that are geographically targeted may result in high levels of under-coverage and leakage, thereby compromising their cost-effectiveness; the lack of clustering questions the appropriateness of current nutrition interventions.     

Characterization of Acidovorax citrulli strains isolated from solanaceous plants

Acidovorax citrulli is the causal agent of bacterial fruit blotch disease of cucurbits. Strains of this pathogen are distributed into two major groups: Group I strains have been mainly isolated from melon and other non-watermelon cucurbits, while Group II strains have been mainly recovered from watermelon. Here we report the characterization of strains T1 and EP isolated from diseased tomato and eggplant plants, respectively, and further confirmed to belong to A. citrulli species. Based on PCR, PFGE, and rep-PCR, these strains showed high similarity to the Group II strain 7a1. Sequencing and comparative analyses revealed that the genomes of T1 and EP aligned with that of the Group II model strain AAC00-1, over 97.88% and 99.22%, respectively. The virulence of T1, EP, and 7a1 determined on tomato, eggplant, and watermelon was similar and significantly higher than that of Group I strain M6. In contrast, M6 was more virulent on melon. Expression levels of seven virulence genes measured 24 hr after inoculation of tomato, eggplant, watermelon, and melon showed that the expression pattern was generally similar in strains 7a1, T1, and EP, whereas for M6 the expression was high only on melon. Overall, our results indicate that the solanaceous strains belong to Group II. To the best of our knowledge, this is the first study that reports characterization of A. citrulli strains isolated from solanaceous species. The fact that A. citrulli is able to naturally colonize and cause disease in non-cucurbit crops poses additional challenges for management of this important pathogen.     

Potential bioavailability of protein and lipids in feed ingredients for the three‐spot cichlid Amphilophus trimaculatus: An in vitro assessment

For the commercial culture of the three‐spot cichlid (Amphilophus trimaculatus), it is important to have available a set of protein and lipid ingredients suitable for feed manufacturing, which allow to optimize the culture at affordable costs. The in vitro digestibility was evaluated with pH‐stat technique, using stomach and intestine multi‐enzymatic extracts from A. trimaculatus juveniles. The digestion of protein ingredients was taken place both in acid and in alkaline conditions, quantifying the total of free amino acids at the end of the hydrolysis, whereas the digestion of lipid ingredients was taken place only in alkaline conditions. The digestive enzymes of this species showed a better affinity to raw materials of animal origin such as beef meal, fish meal and premium chicken meal, which presented better digestibility. The best lipid ingredient that could be used is the fish oil. However, it is possible to use ingredients from the plant sources, such as soy or cereals, and vegetable oils such as olive, corn or soy oil. It is necessary to complement this study in vitro with the digestibility analysis in vivo, in order to determine the inclusion percentages in feeds and costs and therefore to develop an efficient feed formulation for the aquaculture of A. trimaculatus.     

Glyphosate sustainability in South American cropping systems

South America represents about 12% of the global land area, and Brazil roughly corresponds to 47% of that. The major sustainable agricultural system in South America is based on a no-tillage cropping system, which is a worldwide adopted agricultural conservation system. Societal benefits of conservation systems in agriculture include greater use of conservation tillage, which reduces soil erosion and associated loading of pesticides, nutrients and sediments into the environment. However, overreliance on glyphosate and simpler cropping systems has resulted in the selection of tolerant weed species through weed shifts (WSs) and evolution of herbicide-resistant weed (HRW) biotypes to glyphosate. It is a challenge in South America to design herbicide- and non-herbicide-based strategies that effectively delay and/or manage evolution of HRWs and WSs to weeds tolerant to glyphosate in cropping systems based on recurrent glyphosate application, such as those used with glyphosate-resistant soybeans. The objectives of this paper are (i) to provide an overview of some factors that influence WSs and HRWs to glyphosate in South America, especially in Brazil, Argentina and Paraguay soybean cropped areas; (ii) to discuss the viability of using crop rotation and/or cover crops that might be integrated with forage crops in an economically and environmentally sustainable system; and (iii) to summarize the results of a survey of the perceptions of Brazilian farmers to problems with WSs and HRWs to glyphosate, and the level of adoption of good agricultural practices in order to prevent or manage it.     

Limited morphological,physiological and genetic diversity of Phytophthora palmivora from cocoa in Papua New Guinea

In Papua New Guinea (PNG) cocoa (Theobroma cacao) is one of the most important cash crops grown in the tropical lowland and island regions. As in most cocoa‐growing areas, phytophthora black pod and canker cause significant yield losses. Cocoa breeding activities in PNG are focused in East New Britain province where disease control recommendations are also developed. This study tested the hypothesis that there was no diversity in the Phytophthora palmivora population causing black pod on cocoa by characterizing the variation in pathogen populations within and between the five major cocoa‐growing areas. Diseased pods were sampled hierarchically from the five locations and additional isolates were collected from soil, stem and leaf lesions, or retrieved from culture collections. Morphological characters showed continuous variation within the range described for P. palmivora. Genetic analysis revealed that the isolates belonged to one dominant clonal lineage, with restricted distributions of several other subpopulations. Lowest diversities were found in the geographically isolated Karkar Island and East Sepik province. Soil isolates showed greater genetic diversity than isolates from cocoa lesions. Intra‐farm variation was as much as inter‐farm or inter‐province variation. Both mating types were detected, although no strong evidence of sexual recombination was observed. The analysis revealed limited geographic, temporal or host specialization, suggesting continuous selection for pathogenicity from a genetic pool of P. palmivora. These findings have significant implications on the deployment of cocoa genotypes, enforcement of inter‐province quarantine and sustainable disease management strategies.     

An integrated spatial assessment of the investment potential of three species in southern Ontario, Canada inclusive of carbon benefits

This study explores the economic feasibility of several long-rotation afforestation scenarios for southern Ontario, Canada. Three species, red pine (Pinus resinosa Ait.), Norway spruce (Picea abies L.) and black walnut (Juglans nigra L.) are examined. We integrate growth and yield models, site suitability maps, and several management scenarios to investigate the investment attractiveness of these species inclusive and exclusive of carbon sequestration values. We report net present values (NPV), internal rates of return (IRR) and two break-even price metrics. For wood value only scenarios the IRRs range from 4.3 to 4.6% for red pine and 3.4–3.6% for Norway spruce (for the most attractive 10,000 ha, in a single rotation scenario). Black walnut had rates of return 3.5–3.7% for the most attractive 10,000 ha area. Adding carbon valued at Cdn $3.4 per metric ton CO_2 − e (roughly 2005 prices in the Chicago Climate Exchange) increases rates of return by about 0.6% for red pine and Norway spruce and 0.4% for black walnut scenarios. Perhaps surprisingly these returns are comparable and better than 20-year rotation hybrid poplar plantations. To achieve a 6% real rate of return break-even carbon prices were $10.7/t CO_2 − e for red pine, $12.6/t CO_2 − e for Norway spruce and $17.2/t CO_2 − e for black walnut (again for the “best” 10,000 ha). Although somewhat unremarkable, the results suggest that these longer-rotation species may be a better investment than perhaps previously expected if landowners have the appropriate site conditions.