Preliminary trials of the BioBaler working in Brazilian eucalypt plantations

The increasing demand for renewable energy feedstock has raised interest in growing eucalypts for fuel wood production, which is achieved by establishing very dense plantations cut every 18–24 months. The high moisture content of fresh Eucalyptus may handicap cut-and-chip operations, and offers a unique opportunity for supply chains based on baling. Therefore, the Canadian-made BioBaler was tested in Brazil on a eucalypt energy plantation, as well as on the resprouts generated by a conventional pulpwood plantation after severe frost damage. The BioBaler coped well with both crops, achieving high productivity levels: 7.1 and 3.3 t h^?1 in the energy plantation and the failed crop treatments, respectively. Harvesting cost was estimated at €13 t^?1 and €26 t^?1 for the energy plantation and the failed crop, respectively. Productivity and harvesting cost were comparable with those reported in previous studies conducted in other countries on similar crops. Productivity was directly proportional to field stocking. Future studies should test the machine on a wider range of work conditions and include bale extraction, storage, processing and transportation, in order to estimate an overall supply chain cost and allow direct comparison with alternative options.     

Effect of rapamycin treatment during post‐activation and/or in vitro culture on embryonic development after parthenogenesis and in vitro fertilization in pigs

This study investigated the effects of early induction of autophagy on embryonic development in pigs. For this, oocytes or embryos were treated with an autophagy inducer, rapamycin (RP), during post‐activation (Pa), in vitro fertilization (IVF) and/or in vitro culture (IVC). When parthenogenesis (PA) embryos were untreated (control) or treated with various concentrations of RP for 4 hr during Pa, 100 nm RP showed a higher blastocyst formation (48.8 ± 2.7%) than the control (34.6 ± 3.0%). When PA embryos were treated during the first 24 hr of IVC, blastocyst formation was increased (p < .05) by 1 and 10 nm RP (61.9 ± 3.0 and 59.6 ± 3.0%, respectively) compared to the control (43.2 ± 1.8%) and 100 nm RP (47.8 ± 3.2%), with a higher embryo cleavage in response to 10 nm RP (87.3 ± 2.4%) than the control (74.1 ± 3.2%). RP treatment during IVC and Pa + IVC showed increased blastocyst formation (44.7 ± 2.5 and 44.1 ± 2.0%, respectively) compared to the control (33.2 ± 2.0%). In addition, RP treatment during Pa and/or IVC increased glutathione content and inversely reduced reactive oxygen species. In IVF, RP treatment for 6 hr during IVF significantly increased embryonic development (34.0 ± 2.6%) compared to the control (24.8 ± 1.6%), but treatment during IVC for 24 hr with RP did not (23.0 ± 3.8%). Autophagy was significantly increased in PA oocytes by the RP treatment during Pa but not altered by the treatment during the first 24 hr of IVC. Overall, RP treatment positively regulated the pre‐implantation development of pig embryos, probably by regulating cellular redox state and stimulating autophagy.     

Transfer of sulphamethazine from contaminated dairy feed to cows' milk.

Four groups of four healthy mid-lactation Friesian cows were fed a compound feeding stuff containing either 2, 10 or 250 mg sulphamethazine/kg, corresponding to 0, 2, 10 and 250 per cent of the therapeutic inclusion rate in rations for pigs, at a flat rate of 3 kg twice daily for 21 days, followed by a seven-day withdrawal period. The cows were machine-milked twice daily and pooled milk samples from each cow were analysed by a commercially available microbiological assay with a sensitivity of 100 micrograms/litre and by a high performance liquid chromatography (HPLC) procedure with a limit of detection of 10 micrograms/litre. No sulphamethazine was detected by HPLC in the milk samples taken from any of the cows fed the concentrate containing 2 or 10 mg/kg. The milk samples from all four cows fed the highest concentration of sulphamethazine contained from 21 to 120 micrograms/litre while they were being fed the contaminated concentrate. The cow with the highest concentrations of sulphamethazine was the only one which repeatedly tested positive by the microbiological assay. The concentration of sulphamethazine declined rapidly during the withdrawal period and the drug was not detectable by either method in samples taken from two days after the contaminated feed was withdrawn.     

Coupling ecosystem and individual‐based models to simulate the influence of environmental variability on potential growth and survival of larval sprat (Sprattus sprattus L.) in the North Sea

To investigate the impact of changing environmental conditions in the North Sea on the distribution and survival of early life stages of a marine fish species, we employed a suite of coupled model components: (i) an Eulerian coupled hydrodynamic/ecosystem (Nutrients, Phyto‐, Zooplankton, Detritus) model to provide both 3‐D fields of hydrographical properties, and spatially and temporally variable prey fields; (ii) a Lagrangian transport model to simulate temporal changes in cohort distribution; and (iii) an individual‐based model (IBM) to depict foraging, growth and survival of fish early life stages. In this application, the IBM was parameterized for sprat (Sprattus sprattus L.) and included non‐feeding (egg and yolk‐sac larval) stages as well as foraging and growth subroutines for feeding (post‐yolk sac) larvae. Sensitivity analyses indicated that the angle of visual acuity, assimilation efficiency and the maximum food consumption rate were the most critical intrinsic model parameters. As an example, we applied this model system for 1990 in the North Sea. Results included not only information concerning the interplay of temperature and prey availability on larval fish survival and growth but also information on mechanisms underlying larval fish aggregation within frontal zones. The good agreement between modelled and in situ estimates of sprat distribution and growth rates in the German Bight suggested that interconnecting these different models provided an expedient tool to scrutinize basic processes in fish population dynamics.     

旋毛虫感染兔血清抗体消长规律的研究

应用旋毛虫肌幼虫干燥冷浸可溶性抗原与聚醛化聚苯乙烯（ＰＡＰＳ）载体微球共价交联制成快诊试剂,对旋毛虫感染兔血清进行检测,初步探明其血清抗体的消长规律。实验显示,以１６０００条肌幼虫／只经口饲喂感染１０只兔,于第７天可检出抗体,并分别于感染后第４５￣４９天先后达到抗体最高水平,然后维持一段时间（２０￣３０天左右）,以后逐渐缓缓下降。此结果与旋毛虫肌幼虫感染宿主后的生活周期相吻合。肌幼虫在肠道内发育为     

Variations in the drift of larval cod (Gadus morhua L.) in the Baltic Sea: combining field observations and modelling

Coupled three-dimensional (3-D) physical oceanographic modelling and field sampling programmes were carried out in May 1988 and August 1991 to investigate the potential drift of larval cod ( Gadus morhua L.) in the Bornholm Basin of the Baltic Sea. The goals were to predict the transport of cod larvae, thus aiding the identification of physical processes influencing larval retention/dispersal. Numerical simulations were performed using a 3-D eddy-resolving baroclinic model based on the Bryan–Cox–Semtner code adapted for the Baltic Sea. Within the Bornholm Basin, the model was initialized with ground truth data of physical parameters obtained on the research cruises, and all simulations were forced with actual wind data. Outside the basin, generalized hydrographic features of the Baltic Sea were utilized by incorporation of simulated hydrographic fields from previous model runs typical for the time periods considered. Larval drift was simulated either by incorporation of passive drifters, or as the initial horizontal distribution of larvae implemented into the model. Drift model simulations of larval transport agreed relatively well with field observations. The influence of variations in the vertical distribution on a smaller scale, i.e. vertical deviations of ± 6 m from the observed mean centre of mass, on the drift was examined, revealing no significant differences in the drift of larvae depending on their vertical distribution. The different wind forcing during the investigated time periods was linked to a retention situation in May 1988 and to a dispersal situation in August 1991. Finally, observed spatial distribution patterns of 1-group cod based on Baltic Young Fish Surveys (BYFS) were compared with their predicted transport in the larval phase and examined with respect to recruitment.     

Generation of embryonic stem‐like cells from in vivo‐derived porcine blastocysts at a low concentration of basic fibroblast growth factor

Although basic fibroblast growth factor (bFGF) is an essential factor supporting the maintenance of porcine embryonic stem (ES) cell self‐renewal and pluripotency, its high cost has limited previous studies, and the development of a low‐cost culture system is required. For these systems, in vivo blastocysts were progressively cultured under various conditions consisting of different culture mediums and/or different feeder cell numbers at a low concentration of bFGF. As the results, the sequential culture of in vivo‐derived porcine blastocysts on 5.0 × 10⁵ mouse embryonic fibroblast (MEF) feeder cells in alpha minimum essential medium‐based medium for primary culture, on 2.5 × 10⁵ MEF feeder cells in Mixture medium for the 1st subpassage, and on 2.5 × 10⁵ MEF feeder cells in DMEM/Ham's F10‐based medium for the post‐2nd subpassage could support the establishment and maintenance of porcine ES‐like cells at the low concentration of bFGF. The established porcine ES‐like cells showed ES cell‐specific characteristics such as self‐renewal and pluripotency. We confirmed that porcine ES‐like cells could be generated from in vivo‐derived porcine blastocysts at a low concentration of bFGF.     

Effect of liveweight and condition score of ewes at mating,and shearing mid-pregnancy,on birthweights and growth rates of twin lambs to weaning

AIMS: To determine the effects of liveweight and condition score of ewes at mating, and shearing mid-pregnancy, on birthweights and growth rates of twin lambs from birth to the time of weaning, and; to determine whether any effect of condition score is independent of liveweight.

METHODS: Romney ewes (n=435) which conceived within a 17-day mating period and successfully gave birth to and reared twin lambs to weaning were used. Ewes were managed during pregnancy so that their total liveweight increased at a level equivalent to the expected growth of the conceptuses. Approximately half of the ewes were shorn 70 days after the mid-point of mating, and the remainder were left unshorn, at which time they had 6-months' wool growth. All lambs were weighed within 12 h of birth and again at weaning.

RESULTS: There was a significant linear relationship (R²=0.99) between mean group liveweight and condition score of ewes at mating (difference of 7.3 kg per 1.0 unit condition score). Liveweight of ewes at mating had small but significant (p<0.05) positive effects on both birthweights and growth rates of twin lambs to weaning. Ewes that had condition scores of 3.5–4.0 (scale 0–5) at mating gave birth to significantly (p<0.05) lighter lambs than ewes that had condition scores <3.5. The condition score of ewes at mating was positively associated with growth rates of lambs, although this effect was largely explained by variation in the liveweight of ewes at mating.

Twin lambs born to ewes shorn mid-pregnancy were significantly (p<0.05) heavier at birth (by 0.4 kg) and at weaning (p<0.05) than those born to unshorn ewes. The heavier weaning weights of lambs born to ewes shorn mid-pregnancy were due to a heavier birthweights rather than increased growth rate.

CONCLUSIONS: Liveweight and condition score of ewes at mating had small positive effects on growth rates to weaning of twin lambs. Shearing mid-pregnancy increased birthweights and weaning weights of twin lambs. To achieve high weaning weights of twin lambs, farmers should ensure ewes attain high liveweights and condition scores at mating and shear mid-pregnancy. It is speculated that the effects of liveweight and condition score of ewes at mating on weaning weights of twin lambs would be greater than those observed in the present study under conditions in which nutrition of the dam is below optimum.