Oxidative effect of l -carnitine on energy metabolism in diploid and triploid rainbow trout ( Oncorhynchus mykiss ): impact on metabolites

l-Carnitine plays a key role in the regulation of energy metabolism and growth in fish. The aim of this study was to determine the effects of dietary l-carnitine levels on carnitine homeostasis and energy metabolism in diploid and triploid trout (Oncorhynchus mykiss). Diploid and triploid trout (29.5 ± 0.6 and 31.8 ± 0.5 g, respectively) were fed with three diets supplemented with 15, 200 or 530 mg l-carnitine/kg, respectively, for 56 days. Compared to 15 mg l-carnitine, total carnitine content increased in the liver by 182% in diploid and by 154% in triploid trout fed 530 mg l-carnitine. In muscle, total carnitine content increased by 60 and 73% in diploid and by 34 and 75% in triploid with the increase in dietary l-carnitine levels. l-Carnitine caused no significant change in the plasma concentrations of metabolites like proteins (ammonia, urea and protein), lipid (triglycerides), carbohydrate (glucose, lactate) and enzyme activities (lipase, lactate, alanine transaminase, lactic acid dehydrogenase). Triploid trout had significantly lower plasma ammonia (P = 0.003), lipase (P = 0.005) and triiodothyronine (T3; P = 0.003) levels than diploid trout. In conclusion, ploidy significantly affected the energy metabolism in rainbow trout, dietary l-carnitine levels altered the l-carnitine homeostasis, but not influence nutritional metabolism.     

Variation in seed production of <Emphasis Type="Italic">Jatropha curcas</Emphasis> L. accessions under tropical dry forest conditions in Ecuador

The Ecuadorian Government has, since the end of 2011, promoted an initiative for using pure jatropha oil, derived from the seeds of Jatropha curcas L., to generate electricity to supply Floreana Island (one of the Galapagos Islands). In the present study, nine elite accessions of J. curcas from tropical dry forests in Ecuador were cultivated for the purpose of evaluating seed production in relation to the propagation method used (seed, cutting). A split-plot design with three replicates was applied. Seed production, measured over a period of 7 years (2009–2015) showed a large year-to-year variation. However, seed production varied significantly among accessions and depended on the propagation method (seeds or cuttings). Propagation by stem cuttings stabilized the variability in the vegetative and seed production components measured, increasing the strength of their relationships with seed yield. The three highest yielding accessions produced 0.28–0.30 kg of seeds tree^?1 year^?1. As seed yield was not correlated with annual precipitation, the year-to-year variation in production of accessions indicates the effect of other factors not considered here, such as agronomic practices. The study findings suggest that agroforestry practices could be developed that would enable J. curcas to play a predominant role in a strategy for tropical dry forests aimed at reducing poverty (also known as pro-poor growth strategy).     

哥斯达黎加森林生态服务补偿机制演进及启示

通过分析哥斯达黎加森林生态服务补偿机制演进历程,总结出其项目类型多样、参加者自主性强、项目合同规范高效、项目资金来源渠道丰富、补偿标准合理、从自愿的补偿向强制性支付转变等对我国有益的启示,并在此基础上提出改进我国森林生态效益补偿机制的建议。     

Assessment of the usage of biodegradable polymeric matrix in vaginal devices to sustain progesterone release in cows

The usage of timed artificial insemination (TAI) at a low cost leading to better reproductive rates has been the aim of several research groups in the field. Usually during TAI protocols, sustained progesterone (P₄) release devices are employed. Most devices are constituted of a nylon skeleton covered with a silicon layer with P₄. A device based on biopolymers was developed in order to reduce costs and decrease its environmental impact. In this study, we compared the kinetics of sustained progesterone release among devices manufactured with a polymeric blend made of polyhydroxybutyrate‐valerate (PHBV) and poly‐ε‐caprolactone (PCL) (DISP) which were compared with DIB® (Internal Bovine Device) used as the control. In the in vitro and in vivo progesterone release tests, two types of biopolymer‐based devices with a superficial area of 147 cm² were used: DISP8 (46% PHBV, 46% PCL and 8% P₄; n  = 4), DISP10 (45% PHBV, 45% PCL, 10% P₄; n  = 4) and DIB® (1 g P₄, 120 cm² area; n  = 3). The in vitro tests were carried out according to USP XXIII specifications and were performed in a dissolutor sink using an alcohol/water mixture (60/40 v/v) as a release media and samples were collected at 2 min, 2, 4, 8, 12, 24, 48, 60, 72, 84 and 96 h. P₄ concentrations were measured through spectrophotometry in a 244 nm long wave. Three to 3 comparisons of angular coefficients of the straight lines obtained by regression analysis of accumulated P₄ concentrations as a function of square root of time were carried out. Furthermore, the diffusion coefficient values of P₄ were also determined for DISP8 and DISP10. The results showed that the concentrations of P₄ were higher in the DISP10 (774.63 ± 45.26 μg/cm²/t^1/2) compared to DISP8 (566.17 ± 3.68 μg/cm²/t^1/2) (P  < 0.05). However, both DISP10 and DISP8 P₄ concentrations did not differ from DIB® (677.39 ± 16.13 μg/cm²/t^1/2). For the analysis of released quantities per day of the in vitro test, four periods were considered: 0–24, 24–48, 48–72 and 72–96 h. In the first 24 h, DISP8 released significantly less P₄ than DISP10 or DIB®, which did not differ among them. Between 24 and 48 h, DISP10 released significantly more P₄ than DIB®. DISP8 released an intermediate P₄ amount and did not differ significantly from DIB® or DISP10. Between 48 and 72 h, P₄ quantity released by DISP10 was significant higher (P  < 0.01) than that of DIB® and DISP8, which did not differ among themselves. Between 72 and 96 h, DISP10 released significantly more P₄ than DIB®, and DISP8 released an intermediate amount which did not differ from DIB® or DISP10 (P  < 0.01). There was interaction between treatment and time (P  = 0.0024). The diffusion coefficient values were: 1.36 × 10^?8 (cm²/s) for DISP10 and 1.12 × 10^?8 (cm²/s) for DISP8. For the in vivo test, ovariectomized crossbred cows received DIB® (n  = 4) or DISP8 (n  = 8) in an alternate design with a non‐balanced sequence (cross‐over) added of measures repeated in time referring to 16 days of blood samples collection. Samples were analyzed through radioimmunoassay in solid phase using the commercial kit of DPC (Diagnostics Products Corporation). Plasma concentrations of P₄ peaked at 4 h after the placement of the device, this being the only time in which plasma P₄ concentrations differed between DIB® (11.45 ± 1.96) compared with DISP8 (9.23 ± 1.15 ng/mL) (P  = 0.027). On day 8, plasma P₄ concentrations were similar for DIB® (2.44 ± 0.09) and DISP8 (1.89 ± 0.13 ng/mL) (P  = 0.58) showing that both devices were able to keep P₄ concentrations above 1 ng/mL in the plasma of the cow during the 16 day in vivo test. In conclusion, devices manufactured with the blend of PHBV/PCL biopolymers can sustain the release of P₄ in a similar manner as silicon.     

Leather quality of beefalo‐Nellore cattle in different production systems

The aim was to compare the effects of two production systems on performance, carcass traits and physical‐mechanical characteristics of leather from Beefalo‐Nellore steers and heifers and to determine if the response to the production system was similar for both genders. A total of 40 Beefalo‐Nellore cattle, 20 steers and 20 heifers, were evaluated. Animals were divided into two production systems: slaughtered at 15 (intensive system) or 26 (extensive system) months of age. In the intensive system, all animals received a ration containing 600 g/kg corn silage and 400 g/kg concentrate. In the extensive system, animals were kept on a pasture predominantly based on Brachiaria sp. and supplemented with 2 kg/day concentrate. In the intensive system, there was no difference in slaughter weight (470 kg body weight) between steers and heifers but steers in the extensive system had greater slaughter weight than heifers (463 and 428 kg body weight, respectively). Leather weight was higher for animals in the intensive than extensive system but there was no difference in leather weight once excess fat was removed. Leather quality from Beefalo‐Nellore cattle slaughtered at 15 or 26 months of age is similar although carcass yield is higher for cattle slaughtered at a younger age.     

Patterns of lymph node metastasis identified following bilateral mandibular and medial retropharyngeal lymphadenectomy in 31 dogs with malignancies of the head

Variable pathways of lymphatic drainage have been described in the dog head and neck. The aim of this study was to retrospectively assess the patterns of lymph node metastasis in dogs with malignancies of the head following bilateral mandibular and medial retropharyngeal lymphadenectomy. Thirty‐one dogs were included. Median age at surgery was 10 years (range: 5 months to 14 years) and mean bodyweight was 21.4 ± 11.9 kg. Lymph node metastasis occurred in 14 dogs (45%), with spread to mandibular lymph nodes in 14 dogs and medial retropharyngeal metastasis in 11 dogs. Eight of 13 dogs (62%) with lymphatic metastasis and a lateralised lesion showed contralateral dissemination, while 12/13 (92%) showed ipsilateral metastasis. Of 13 dogs with oral malignant melanoma, four showed metastasis to all four lymph centres. Contralateral metastasis may occur in dogs with malignancies of the head and should be considered during staging and management.     

The potential of Eucalyptus plantations to restore degraded soils in semi-arid Morocco (NW Africa)

Key message

Short-rotation forestry using eucalyptus in degraded oak forests in the semi-arid area of NW Morocco can be a useful strategy to avoid further degradation and carbon loss from this ecosystem, but it might be constrained by nutrient and water supply in the long term.

Context

Land degradation and deforestation of natural forests are serious issues worldwide, potentially leading to altered land use and carbon storage capacity.

Aims

Our objectives were to investigate if short-rotation plantations can restore carbon pools of degraded soils, without altering soil fertility.

Methods

Carbon and nutrient pools in above- and below-ground biomass and soils were assessed using stand inventories, harvested biomass values, allometric relationships and selective sampling for chemical analyses.

Results

Carbon pools in the total ecosystem were low in the degraded land and in croplands (6–13 Mg ha^?1) and high in forests (66–94 in eucalyptus plantations; 86–126 in native forests). The soil nutrient status of eucalyptus stands was intermediate between degraded land and native forests and increased over time after eucalyptus introduction. All harvest scenarios for eucalyptus are likely to impoverish the soil but, for the moment, the soil nutrient status has not been affected.

Conclusion

Afforestation of degraded land with eucalyptus can be a useful restoration tool relative to carbon storage and soil fertility, provided that non-intensive forestry is applied.

     

Bioavailability of Metals at a Southeastern Brazilian Coastal Area of High Environmental Concern Under Anthropic Influence: Evaluation Using Transplanted Bivalves (<Emphasis Type="Italic">Nodipecten nodosus</Emphasis>) and the DGT Technique

Metals are commonly determined in aquatic organisms, primarily using bivalves to provide important data on their bioavailability. The technique of diffusive gradients in thin films (DGTs) has also been employed to assess the concentration of metals in freshwater and marine environments, determining their lability. The present work evaluated and compared the labile and bioavailable concentrations of Cd, Co, Cu, Mn, Ni and Pb in seawater from Ilha Grande Bay, RJ, using DGT and transplanted bivalves (Nodipecten nodosus), respectively. The scallops and DGTs were immersed in water at three sampling locations within the bay from July to September 2012 (winter campaign) and from December 2012 to February 2013 (summer campaign). The metals were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). DGT technique was successfully used to determine the concentrations of metals in waters, except for Pb when short deployment times were used. All metals were determined using transplanted bivalves (N. nodosus), but pre-exposure to Cd was evident, which made the interpretation of the data for this analyte difficult. The data on metal lability in Ilha Grande Bay waters obtained from the DGT technique were correlated with the metal bioavailability determined in the soft tissues of the transplanted N. nodosus for Co, Cu, Mn, Ni and Pb. This is the first evaluation of this type for this area of high environmental concern. Both techniques revealed that Náutico was the location with the highest concentration of metals in the study area.