In vivo metabolic fate of [14C]-acetamiprid in six biological compartments of the honeybee, Apis mellifera L

The in vivo metabolism of acetamiprid was studied in the honeybee, Apis mellifera L. The distribution of acetamiprid and its metabolites was monitored over a 72-h period in six biological compartments: head, thorax, abdomen, haemolymph, midgut and rectum. Honeybees were treated orally with 100 microg [14C]-acetamiprid kg(-1) bee, a dose which is about 1500 times lower than the median lethal dose. After 72 h, only 40% of the total radioactivity was eliminated, suggesting that acetamiprid and its metabolites tended to persist in the honeybee. Acetamiprid was rapidly distributed in all compartments and metabolized. Just after administration, radioactivity was mainly localized in the abdomen and subsequently in the rectum. After 72 h, the maximum amount of radioactivity (about 20% of the ingested dose) was detected again in the abdomen, whereas the lowest level of total radioactivity was detected in the haemolymph. Radioactivity in the head did not exceed 7.6% of total ingested radioactivity. More than 50% of acetamiprid was metabolised in less than 30 min, indicating a very short half-life for the compound. During the first hours, acetamiprid was mainly detected in nicotinic acetylcholine receptor-rich tissues: abdomen, thorax and head. Of the seven metabolites detected, the major ones were 6-choronicotinic acid and an unknown metabolite called U1, which was present mainly in the rectum, the thorax and the head. Our results indicate that the low toxicity of acetamiprid may reflect its rapid metabolism.     

Equine Infectious Anemia Virus (EIAV): what has HIV's country cousin got to tell us?

Equine Infectious Anemia Virus (EIAV) is a lentivirus, of the Retrovirus family, with an almost worldwide distribution, infecting equids. It causes a persistent infection characterized by recurring febrile episodes associating viremia, fever, thrombocytopenia, and wasting symptoms. The disease is experimentally reproducible by inoculation of Shetland ponies or horses with EIAV pathogenic strains. Among lentiviruses, EIAV is unique in that, despite a rapid virus replication and antigenic variation, most animals progress from a chronic stage characterized by recurring peaks of viremia and fever to an asymptomatic stage of infection. The inapparent carriers remain infective for life, as demonstrated by experimental transfer of blood to naive animals. The understanding of the correlates of this immune control is of great interest in defining vaccine strategies. Research on EIAV, this "country cousin" of HIV (Human Immunodeficiency Virus), over the last five decades has produced some interesting results on natural immunological control of lentivirus replication and disease and on the nature and role of virus variation in persistence and pathogenesis. These studies are of interest in the context of HIV and efforts to develop a vaccine. This review will focus on some of the most recent results.     

In growing pigs,nutritive value and nutrient digestibility of distillers’ by-products obtained from two varieties of rice

In South-East Asia, rice distillers’ by-product (RDP) is a widely abundant feedstuff whose adequate incorporation into pig diets is still questionable. Especially, effects of RDP on nutrient digestibility of growing pigs fed corn-soybean meal-based diet are lacking. The objective of this study was to determine nutrient digestibility and energy value of ordinary (ORDP) and glutinous (GRDP) rice distillers’ by-product in growing pigs. Two groups of 12 castrated crossbred barrows (Duroc × Landrace × Yorkshire), about 3 months old, 38?±?1.04-kg initial body weight, were each allocated to a 15-day experiment in which pigs were divided into three isonitrogenous diet-groups. The animals were housed individually in metabolism cages for separated collection of feces and urine. Each diet-group was provided either a control corn-soybean meal diet or a diet in which corn and soybean meal were partly replaced by ORDP or GRDP at 15 or 30% on diet dry matter basis. Glutinous by-product especially showed higher levels in crude protein, neutral/acid detergent fiber, total branched-chain amino acids, and butyric acid. When compared to the control diet, ORDP tented to increase DM intake (P?= 0.054) but decreased energy (P?< 0.001) and crude protein (P?< 0.04) digestibility, while GRDP decreased DM intake (P?< 0.001). Both GRDP and ORDP products negatively affected digestibility of ether extract. The average digestible and metabolizable energy of ORDP and GRDP were 17.0 and 16.6, and 17.7, and 17.1 MJ/kg DM, respectively. In conclusion, these results show that both RDP, and especially GRDP, are highly valuable protein and energy sources for pig production.

     

Forest recovery since 1860 in a Mediterranean region: drivers and implications for land use and land cover spatial distribution

Context

Land use and land cover (LULC) change is a major part of environmental change. Understanding its long-term causes is a major issue in landscape ecology.

Objectives

Our aim was to characterise LULC transitions since 1860 and assess the respective and changing effects of biophysical and socioeconomic drivers on forest, arable land and pasture in 1860, 1958 and 2010, and of biophysical, socioeconomic and distance from pre-existing forest on forest recovery for the two time intervals.

Methods

We assessed LULC transitions by superimposing 1860, 1958 and 2010 LULCs using a regular grid of 1 × 1 km points, in a French Mediterranean landscape (195,413 ha). We tested the effects of drivers using logistic regressions, and quantified pure and joint effects by deviance partitioning.

Results

Over the whole period, the three main LULCs were spatially structured according to land accessibility and soil productivity. LULC was driven more by socioeconomic than biophysical drivers in 1860, but the pattern was reversed in 2010. A widespread forest recovery mainly occurred on steeper slopes, far from houses and close to pre-existing forest, due to traditional practice abandonment. Forest recovery was better explained by biophysical than by socioeconomic drivers and was more dependent on distance from pre-existing forest between 1958 and 2010.

Conclusions

Our results showed a shift in drivers of LULC and forest recovery over the last 150 years. Contrary to temperate regions, the set-aside of agricultural practices on difficult land has strengthened the link between biophysical drivers and LULC distribution over the last 150 years.

     

Palatability of nine fodders species used by guinea pigs (Cavia porcellus)

Tropical Animal Health and Production - Nine fodders commonly offered to the guinea pigs by the breeders in Lubumbashi (Democratic Republic of Congo) were compared for chemical composition and for...     

Impact of dry solids and bile acid concentrations on bile acid binding capacity of extruded oat cereals

Extruded breakfast cereals (EBC), processed from two oat lines, N979-5-2-4 (N979) and "Jim", with beta-glucan concentrations of 8.7 and 4.9%, respectively, were used to determine the impact of dry solids (DS) and bile acid (BA) concentrations on in vitro BA binding efficiency. A full fractional factorial design with levels for BA concentrations of 0.20, 0.47, 0.95, 2.37, and 4.73 micromol/g of total EBC slurry and for DS in the slurries of 0.8, 2, 3, and 4% (w/w) was selected. The absolute amount of BA bound (micromol) was measured for each trial in the experiment design. The percentage (%) of BA bound based on the total amount of BA added and BA bound per gram of DS of the EBC (micromol/g) were also presented and discussed. N979 in vitro digestion slurries had greater BA binding (micromol) than Jim slurries at different DS and BA concentrations, with greater differences at DS of 3% or above and at BA concentrations of 2.37 micromol/g or above. No difference in the absolute amount of BA bound (micromol) and percentage (%) BA bound occurred between the EBC slurries made from the two oat types at the lowest DS of 0.8% or the lowest BA concentration of 0.20 micromol/g. The efficiency of BA binding by beta-glucan in these two EBC became more distinguishable at 3% DS or above and BA concentrations of 2.37 micromol/g or above, indicating that these two conditions can be employed to measure BA capacities for similar foods. Also, the beta-glucan in the EBC produced from the N979 oat line was more soluble than that from the EBC produced from the Jim oat line. Thus, greater BA binding capacity may have been caused by both a greater amount of beta-glucan and a greater solubility of beta-glucan in N979 than in Jim EBC.     

The effect of density on sea bass (Dicentrarchus labrax) performance in a tank-based recirculating system

Sea bass (Dicentrarchus labrax) (135 ± 4 g) were reared under tank-based recirculating aquaculture system for a 63-day period at four densities: 10, 40, 70, 100 kg m^?3. Fish performance, stress indicators (plasma cortisol, proteonemia plus other blood parameters—Na⁺, K⁺, glucose, pH, total CO₂^?) and water quality were monitored. At the end of the 63-day period, resistance to infection was also studied by a nodavirus challenge. A 25-day test was performed on fish from two extreme densities (10 and 100 kg m³) and one intermediate density (40 kg m³).With regards to the different density treatments, there was no significant difference between the daily feed intake (DFI) and the specific growth rate (SGR) up to a density of 70 kg m^?3. No significant difference was found between treatments concerning the feed conversion ratio (FCR) and the mortality rate. No density effect was observed on the fish stress level (plasma cortisol) or on sensitivity to the nodavirus challenge. Under these experimental rearing conditions, the density above 70 kg m^?3 has an impact on growth performance (DFI and SGR) indicators and also some blood parameters (CO₂) at the highest density tested (100 kg m^?3).This study suggests that a density up to 70 kg m^?3 has no influence on sea bass performance and welfare. At 100 kg m^?3, average specific growth rate was decreased by 14% without welfare deterioration according to the welfare indicators monitored.     

Effect of exogenous circulating anti-bPL antibodies on bovine placental lactogen measurements in foetal samples

Background

The involvement of placental lactogen (PL) in the regulation of foetal growth has been investigated in different species by in vivo immunomodulation techniques. However, when circulating antibodies are present together with the hormone, the procedure for hormonal measurement becomes considerably complex. The aim of this study was the immunoneutralization of bovine placental lactogen (bPL) concentrations in bovine foetal circulation by direct infusion of rabbit anti-bPL purified immunoglobulins (IgG) via a foetal catheter (in vivo study). The ability of a RIA based on guinea pig anti-bPL antiserum, for the measurement of bPL concentrations in samples containing exogenous rabbit anti-bPL immunoglobulins, was also analyzed in in vitro and in vivo conditions.

Methods

Six bovine foetuses were chronic cannulated on the aorta via the medial tarsal artery. Infusion of rabbit anti-bPL IgG was performed during late gestation. Pooled rabbit anti-bPL antisera had a maximal neutralization capacity of 25 μg bPL/mL of immunoglobulin. Interference of rabbit anti-bPL immunoglobulin with radioimmunoassay measurement using guinea pig anti-bPL as primary antibody was first evaluated in vitro. Polyclonal anti-bPL antibodies raised in rabbit were added in foetal sera to produce 100 samples with known antibodies titers (dilutions ranging from 1:2,500 till 1:1,280,000).

Result(s)

Assessment of the interference of rabbit anti-bPL antibody showed that bPL concentrations were significantly lower (P < 0.05) in samples added with dilutions of rabbit antiserum lower than 1:80,000 (one foetus) or 1:10,000 (four foetuses). It was also shown that the recovery of added bPL (12 ng/mL) was markedly reduced in those samples in which exogenous rabbit anti-bPL were added at dilutions lower than 1:20,000. Concentrations of foetal bPL were determined in samples from cannulated foetuses. In foetuses 1 and 6, bPL concentrations remained almost unchanged (<5 ng/mL) during the whole experimental period. In Foetus 3, bPL concentrations decreased immediately after IgG infusion and thereafter, they increased until parturition.

Conclusion(s)

The use of a bPL RIA using a guinea pig anti-bPL as primary antiserum allowed for the measurement of bPL concentrations in foetal plasma in presence of rabbit anti-bPL IgG into the foetal circulation. Long-term foetal catheterization allowed for the study of the influence of direct infusion of anti-bPL IgG on peripheral bPL concentrations in bovine foetuses.     

Using public databases for genomic prediction of tropical maize lines

In this paper, the aims were (a) to test the usefulness of using genomic and phenotypic information from public databases (open access) to predict genetic values for tropical maize inbred lines regarding plant and ear height; (b) to identify how the population structure, the use of optimized training sets (OTSs) and the amount of information originating from public databases affect the predictive ability. Thus, 29 training sets (TSs) were defined considering three diversity panels: the University of São Paulo (USP—validation set (VS)) and the ASSO and USDA North Central Regional Plant Introduction Station (NCRPIS) (external public panels—predictors), which were divided into four scenarios with different TS configurations. We showed that it is possible to use public datasets as a primary TS and that population structure can modify the predictive abilities of GS. In the four scenarios proposed, very large or very small sets did not provide predictive abilities over 0.53 for GS. However, OTSs composed of 250 individuals were sufficient to achieve predictive abilities over this limit.