Lipid metabolism in juveniles of Yellowtail,Seriola dorsalis,fed different levels of dietary methionine containing a low level of cholesterol: Implication in feed formulation

The involvement of dietary methionine in the lipid metabolism of Seriola dorsalis, at different levels of dietary methionine (Met), and low content of cholesterol was investigated. Four diets containing different Met levels and a low amount of cholesterol (0.23 g/kg diet) were prepared. One hundred and eighty juveniles (16.2 ± 1.5 g) were randomly distributed into each 12 500‐L ponds. After 60 days, the growth in weight (%) significantly increased following the Met supplementation, whereas SGR of all the experimental treatments was higher than the Basal Diet. The expression of the insulin‐like growth factor (IGF‐1) increased significantly (0.2‐fold) and was complemented by significant changes in Mat, BHMT and HMG‐CoA, for fish that were in the low and higher Met levels. The cholesterol content in the whole body and liver increased following methionine supplementation, similarly to that observed for crude lipids, in particular in the whole body and liver tissues. However, the relative amount of most fatty acids remained unchanged. Only the oleic acid increased at a higher amount of Met. Therefore, once the dietary requirement of methionine is met, the methionine is used to synthesize cholesterol. It is recommended to supply a higher amount of methionine to spare energy for growth.     

The role of dietary methionine concentrations on growth,metabolism and N‐retention in cobia (Rachycentron canadum) at elevated water temperatures

This study determined impacts of dietary methionine concentrations at two temperatures on growth, feeding efficiency and N‐metabolites in juvenile cobia. Methionine concentrations of the experimental diets were deficient (M9; 9 g/kg), sufficient (M12; 12 g/kg) and surplus (M16, 16 g/kg). Water temperature was normal (30°C) or elevated (34°C). Twenty cobia in triplicate tanks were fed the experimental diets for 6 weeks. Both methionine and temperature affected cobia's growth and feeding efficiency. Cobia fed M9 performed lower than the fish fed M12 and M16 diets. Additionally, cobia reared at 34°C performed poorer than at 30°C, probably due to lower voluntary feed intake in the fish reared at 34°C. Protein efficiency ratio and protein productive value in cobia fed M9 diet were less than M12 or M16 diets. This was confirmed with the improved retentions of indispensable amino acids (AAs). No interactions between methionine and temperature were observed in growth and protein accretion. At 30°C, CF improved, while HSI and VSI declined upon methionine supplementation levels. Of which an interaction between temperature and methionine was present. Plasma, muscle and liver free AA and N‐metabolites were affected by methionine and temperature. Furthermore, temperature affected cobia's lipid class composition, resulting in increased phospholipids and cholesterol at 34°C.     

Ecosystem services provided by heavy metal-contaminated soils in China

Purpose

Soils provide a variety of ecosystem services (ESs) that are crucial to food security, water security, energy security, climate change abatement, and biodiversity, especially in densely populated countries such as China. At present, China is facing great challenges from serious soil heavy metal (HM) contamination which has damaged soil ESs and soil security. In this paper, we evaluate the ESs that contaminated soils can potentially provide before and after remediation, and we explore the connections between these ESs and the achievement of soil security in China.

Materials and methods

After an introduction to the concepts of ESs and soil security and a review of the current status of soil HM contamination in China, the ESs that can potentially be provided by HM-contaminated soils are discussed. Finally, we discuss the current remediation status of HM-contaminated soils from the standpoint of optimizing the ability of these soils to provide ESs.

Results and discussion

The status of the provision of ESs by HM-contaminated soils of croplands, brownfields, and mining wastelands is described in detail. Contaminated cropland soils fail to provide provisioning (e.g., food production), cultural, and regulating services, while the regulating and supporting services of brownfield soils are greatly reduced. The ESs of mining wasteland soils have been severely damaged, resulting in a high potential for contamination of surrounding ecosystems. Recent soil remediation projects have demonstrated that the damaged ESs of HM-contaminated soils can be restored, which would enhance Chinese soil security. However, it has often been the case that only visible ESs (e.g., food production and vegetation cover) are addressed, while other less noticeable but important services (e.g., water quality and biodiversity) are neglected. Therefore, we propose a framework for the evaluation of ESs provided by HM-contaminated soils.

Conclusions

The ESs that could potentially be provided by HM-contaminated soils would help to achieve soil security in China, not only by improving food security, water security, and energy security but also by helping to protect soil biodiversity and abate global climate change. The ESs provided by HM-contaminated soils should be taken into account in soil policy and management systems as well as by the remediation industry.

     

Relationships between agroforestry and community development according to practitioners

Post-adoption studies are relatively uncommon in the agroforestry literature. Thus little is known about progress and permanence following adoption. To better understand the relationship between agroforestry implementation and community development, seventy-seven practitioners in Cameroon with three or more years of experience were surveyed about the relationships between agroforestry and community development. Hypotheses were that they have observed differences in the association between agroforestry and community capitals. They were also surveyed about their satisfaction with agroforestry. Hypotheses were that satisfaction is high and negatively skewed when compared to community capitals measurements. Game play was used to collect responses. Friedman’s two-way non-parametric statistic was used to test for inter-item differences within the community capitals and satisfaction response sets. Shapiro–Wilk statistic was used to test for normality in both response sets and a bootstrap procedure and t-tests were used to test for differences in data skewness and kurtosis. Natural capital scored highest but did not differ significantly from built, human, and social capitals. Financial capital was significantly lower than natural capital, but not built, human, or social capitals. Political and cultural capitals were significantly lower compared to all others. Satisfaction was significantly higher when compared to community capitals, but the data were also negatively skewed suggesting capitals are a more representative and useful metric for researchers and technical assistance professionals focused on long-term practitioner support.     

Recirculation nursery systems for bivalves

In order to increase production of bivalves in hatcheries and nurseries, the development of new technology and its integration into commercial bivalve hatcheries is important. Recirculation aquaculture systems (RASs) have several advantages: high densities of the species can be cultured resulting in a cost-effective production system; optimal temperature maximizes production and allows rapid turnover of the product; stable water quality improves growth rate and minimizes stress and potential loss by diseases. Pilot RAS systems were developed for seed rearing of oysters (Crassostrea gigas), scallops (Pecten maximus), mussels (Mytilus edulis) and clams (Ruditapes decussatus). Optimal feed addition and waste matrix were determined. Based on this, system flow rates were designed. Seed growth in the pilot RAS systems was compared at different renewal rates and with growth in flow-through systems (FTS). All four species can be reared in RAS and showed similar growth in RAS and in FTS or in RAS with a higher renewal rate. RAS can keep O₂, nitrogen and pH within the desired range. Temperature was generally higher in RAS than in FTS, probably due to heat induced by the pump circulating the water. The supply of sufficient amount of food in combination with a desire to reduce the renewal rate calls for use of concentrated feed in RAS.     

Determination of the different components of cadmium short‐term uptake by roots

As the various components of the cadmium (Cd) root sink have not been clearly described, there is a need to precisely measure the respective contributions of apoplast and symplast to short‐term root Cd uptake and to explain the linear component of the absorption isotherms. A new method of fractionating Cd in roots was applied to two plant species with contrasting abilities to accumulate Cd: maize (Zea mays) and a Cd‐hyperaccumulating ecotype of alpine pennycress (Noccaea caerulescens). Their roots were exposed for 1 h to increasing concentrations of labeled Cd. Series of desorption baths were used to obtain the root apoplastic Cd in combination with a brief freezing step in liquid nitrogen to separate the intracellular metal from the apoplastic one. The apoplastic uptake accounted for 15% to 82% and for 48% to 96% of the total Cd uptake of maize and of alpine pennycress roots, respectively. In the case of maize, the concentration‐dependent symplastic net flux fitted a biphasic Michaelis‐Menten function, while in the case of alpine pennycress, a Michaelis‐Menten‐plus‐linear function proved a better fit. The second component of the symplastic net flux may reflect absorption through a low‐affinity transport system. Short‐term Cd uptake by roots is dominated by the high‐affinity transport system for exposure concentrations below 1 μM for maize and 0.2 μM for alpine pennycress, while cell‐wall binding prevailed for higher exposure concentrations.     

Biologically active components of a Papua New Guinea analgesic and anti-inflammatory lichen preparation

A traditional preparation of Parmotrema saccatilobum (Taylor) Hale (Family: Parmeliaceae) is being considered for inclusion into the PNG national drug formulary by the Ministry of Health Taskforce on Traditional Medicines. The lichen preparation is traditionally used in the Milne Bay province of Papua New Guinea for analgesic and anti-inflammatory activities. A hexane extract of P. saccatilobum yielded the principle components atranorin and chloroatranorin. Atranorin and chloroatranorin were tested in a COX-1 and -2 enzyme inhibition assay, which showed that atranorin inhibited COX-1 in a dose dependent manner and suggests partial inhibition by atranorin and chloroatranorin of COX-2 and COX-1, respectively.     

Organic residue mass at planting is an excellent predictor of tree growth in Eucalyptus plantations established on a sandy tropical soil

Tropical plantation forests are meeting an increasing proportion of global wood demand and comprehensive studies assessing the impact of silvicultural practices on tree and soil functioning are required to achieve sustainable yields. The objectives of our study were: (1) to quantify the effects of contrasting organic residue (OR) retention methods on tree growth and soil nutrient pools over a full Eucalyptus rotation and (2) to assess the potential of soil analyses to predict yields of fast-growing plantations established on tropical sandy soils. An experiment was set up in the Congo at the harvesting of the first rotation after afforestation of a native herbaceous savanna. Six treatments were set up in 0.26 ha plots and replicated in 4 blocks, with OR mass at planting ranging from 0 to 46.5 Mg ha⁻¹. Tree growth over the whole rotation was highly dependent on OR management at planting. Over-bark trunk volume 7 years after planting ranged from 96 m³ ha⁻¹ in the treatment with forest floor and harvest residue removal at planting to 164 m³ ha⁻¹ in the treatment with the largest amount of OR. A comparison of nutrient stocks within the ecosystem at planting and at the end of the rotation suggested that nutrient contents in OR were largely involved in the different response observed between treatments. OR management treatments did not significantly modify most of the nutrient concentrations in the upper layers of the mineral soil. Conventional soil analyses performed before planting and at ages 1 and 3 years were unable to detect differences between treatments despite large differences in tree growth. In contrast, linear regressions between stand aboveground biomass at harvesting and OR mass at planting (independent variable) showed that OR mass was an excellent predictor of stand yield (R² = 0.99). A large share of soil fertility comes from organic material above the mineral soil in highly weathered sandy soils and OR mass at planting might be used in conjunction with soil analyses to assess the potential of these soils to support forest plantations.