Interactions between different media and follicle‐stimulating hormone supplementation on in vitro culture of preantral follicles enclosed in ovarian tissue derived from collared peccaries (Pecari tajacu Linneaus, 1758)

The aim was to verify the effect of follicle‐stimulating hormone (FSH) supplementation to α‐MEM+ or TCM199+ media on the in vitro development of ovarian preantral follicles (PFs) derived from collared peccaries. Ovaries (n = 5 pairs) were collected and divided into fragments destined to control group (non‐cultured) or treatments that were cultured for 7 days. The PFs morphology, growth and activation were evaluated by classical histology. The immunohistochemistry markers Ag‐NOR and PCNA were used for nuclear proliferation analysis, and the picrosirius red labelling was used for ovarian extracellular matrix (ECM) evaluation. After 7‐day culture, only the TCM199+ treatment maintained the proportion of intact PFs similar to day 1 (63.2%), but no differences were found among treatments (p > .05). In addition, a significant increase in the growing follicles proportion was verified for all the treatments, indicating follicular activation (p > .05). By the Ag‐NOR analysis, only the TCM199+/FSH maintained the nuclear proliferation similar to the first day (p > .05). The picrosirius red staining revealed that the ECM remained intact in all the treatments (p > .05). We suggest the use of TCM199+ medium supplemented of FSH for the in vitro development of peccaries PFs under 7‐day culturing conditions.     

Early weaning and postweaning nutritional management affect feedlot performance of angus x simmental heifers and the relationship of 12th rib fat and marbling score to feed efficiency

Early-weaned Angus x Simmental heifers were used to evaluate the effects of postweaning nutritional management on feedlot performance, carcass merit, and the relationship of intramuscular and subcutaneous fat deposition to the feed efficiency among heifers fed for a high-quality market. Sixteen heifers were weaned at 73+/-5.5 d of age and grazed on endophyte-infected tall fescue for 18 mo before entering the feedlot (early-weaned-P). Eighty heifers from the following year's calf crop were weaned at 71+/-5.5 d of age and allowed either ad libitum access to a 25% concentrate diet (early-weaned-25C) or limit-fed a 90% concentrate diet (early-weaned-90C) to achieve a similar ADG. Following a 119-d growing period, 16 early-weaned-90C and 16 early-weaned-25C calves were paired based on BW and growth rate and individually fed during the finishing period along with the early-weaned-P heifers. Ultrasound measurements of s.c. and i.m. fat were recorded at approximately 60-d intervals throughout the finishing period. Feed efficiency was regressed against s.c. and i.m. fat, and i.m. fat was regressed on s.c. fat. Despite a similar ADG, early-weaned-90C calves gained more efficiently (P < or = 0.05) in the feedlot than early-weaned-25C calves. Heifers finished as yearlings tended (P < or = 0.10) to gain faster but gained less efficiently (P < or = 0.01) than early-weaned-90C heifers finished as calves. The rate of s.c. and i.m. fat deposition was similar between early-weaned-90C and early-weaned-25C heifer calves. The calves were grouped together for comparison to yearlings. Feed efficiency decreased quadratically (P < or = 0.01) as s.c. fat cover increased. The rate at which feed efficiency decreased relative to increasing s.c. fat cover was similar regardless of age at feedlot entry. However, heifers finished as calves gained more efficiently (P < or = 0.01) than yearlings at any given fat thickness. Feed efficiency decreased linearly (P < or = 0.01) as i.m. fat increased among heifers finished as calves. Additionally, heifers finished as calves deposited i.m. fat at a faster rate relative to s.c. fat (P < or = 0.01) than yearlings. These data suggest that heifers finished as calves produce high-quality carcasses with less s.c. fat cover while gaining more efficiently than heifers finished as yearlings.     

Plasma ascorbic acid concentrations in healthy dogs

Using a highly sensitive and selective analytical method and careful stability control, plasma concentrations of ascorbic acid were determined in German Shepherd Dogs, Labrador Retrievers and Siberian Huskies, a total 99 animals. Mean concentration was 35.9 micromol l(-1)(range 18.2-50.7), and no significant variation was observed neither between breeds nor between females and males. These and previous reported data on plasma ascorbic acid levels in dogs are discussed in the light of methodological aspects.     

Assessing antibiotic resistance in fecal Escherichia coli in young calves using cluster analysis techniques

This study uses cluster analysis techniques to describe the antibiotic susceptibility patterns seen in calf fecal Escherichia coli (E. coli). Cohorts of 30 dairy calves at six farms were sampled at 2-week intervals during the pre-weaning period. At each sampling occasion five fecal E. coli isolates per calf were analyzed for antibiotic susceptibility to 12 antibiotics using the disk diffusion method. All isolates had a profile consisting of the aggregate measured inhibition zone size for each of the evaluated antibiotics. Several cluster analytic algorithms were assessed to partition the E. coli isolates. For our data, Ward's minimum variance method met the objectives of the study. Relative to the number of possible combinations of resistance clusters, a parsimonious set of 14 patterns was developed. This set of E. coli isolates exhibited a limited set of resistance patterns to the different antibiotics indicating that certain resistance genes may be linked.     

Echinococcus multilocularis (Cestoda,Taeniidae) in Red foxes (Vulpes vulpes) in northern Belgium

The first record of the tapeworm Echinococcus multilocularis (Cestoda, Taeniidae) in Red foxes (Vulpes vulpes) in northern Belgium is described. Between 1996 and 1999, 237 dead foxes were examined for the presence of this tapeworm using the intestinal scraping technique. Four foxes (1.7%) were found to be infected with E. multilocularis and showed medium to very high parasitic burdens. Three infected foxes originated from the south of the study area and the fourth animal came from the north of the study area near the border with The Netherlands. These findings are discussed in relation to the high endemicity of E. multilocularis in southern Belgium and to the increased distribution of the Red fox (V. vulpes) in northern Belgium during the last two decades.     

Die Differenzierunggas-, rauch- und staubförmiger Immissionen bei landwirtschaftlichen,gartenbaulichen und forstwirtschaftlichen Kulturen

Summary The differentiation between acute, direct chronic and indirect chronic immissions caused by atmospheric pollution brought about by emissions having the nature of gas, smoke and dust is described. Several positive examples are quoted to the question whether indirect chronic immissions are possible without damage to growth up, yield and/or production.A differentiation has value for autotrophic and heterotrophic life forms:1. Insignificant immissions in the animate world prevail when autotrophic/heterotrophic life forms are not adversely affected, as compared with their condition in their usual situation and surroundings, i. e. when: their anatomical/morphological development, their function, their efficiency, their powers of propagation, their immunity to disease, their longevity and their physiological function and/or psychical well-being are not impaired.2. Considerable immissions in the animate world prevail when the development, function, efficiency, powers of propagation, immunity to disease and/or general well-being of autotrophic/ heterotrophic life forms, as compared with their condition in their usual situation and surroundings, are affected by reversible physiological/ psychical disturbances (direct and indirect chronic immissions) but when their longevity remains unaffected and when anatomical/morphological anomalies, changes and/or damage (acute immissions) do not occur.3. Severe immissions in the animate world prevail when the development, function, efficiency, power of propagation, immunity to disease, longevity and/or general well-being of autotrophic/heterotrophic life forms, as compared with their condition in their usual situation and surroundings, is affected or interrupted by repeated or irreversible physiological/psychical disturbances (direct and indirect chronic immissions), whereby, under certain circumstances, limited but typical anatomical/ morphological anomalies, changes and/or damage (acute immissions) occur to separate organic parts.4. Excessive immissions in the animate world prevail when the development, function, efficiency, power of propagation, immunity to disease, longevity and/or general well-being of autotrophic/ heterotrophic life forms, as compared with their condition in their usual situation and surroundings, are prevented or ended by repeated or irreversible physiological changes or by psychical disturbances (direct and indirect chronic immisssions), whereby, under certain circumstances, some organs or complete organisms suffer extended and typical anatomical/morphological anomalies, changes and/or damage (acute immissions).     

Dietary inclusion of crystalline D- and L-methionine: effects on growth, feed and protein utilization, and digestibility in small and large Atlantic salmon (Salmon salar L.)

Use of crystalline methionine to optimize amino acid profiles in feeds for Atlantic salmon (Salmo salar L.) was studied in three experiments. A basic experimental diet with 25% of dietary protein from marine origin and the remaining 75% from soya protein concentrate was used either with or without supplementation of L ‐methionine, D ‐methionine or DL ‐methionine. A fishmeal‐based diet was used as control. In experiment 1, growth performance of 100 g salmon in seawater was improved by supplementation with the different methionine products. Growth performance was, however, inferior to that of fish fed the control. Feed conversion ratios (FCR) exhibited similar trends to specific growth rate (SGR) with methionine supplementation, but again not as the control. Protein retention, measured as productive protein value (PPV), was significantly better in the control and D ‐methionine groups as compared with either L ‐methionine or the nonsupplemented group. These trends were confirmed in experiment 2, using fish of the same size, where an absorption and digestibility study of D ‐ and L ‐methionine clearly indicated that D ‐methionine was absorbed as well as L ‐methionine. Results indicated that racemization of D ‐ into L ‐methionine occurs in liver and kidney in Atlantic salmon. Ornithine decarboxylase (ODC) activity in liver was significantly affected by dietary treatment and there was a good correlation with growth and feed utilization data. In experiment 3, a growth study with large salmon (1 kg) was performed using increasing supplementation of DL ‐methionine to the basic diet. Results indicated a methionine requirement for maximum growth of 9.2 g kg^–1 feed dry matter (DM) kg^–1 growth. This is slightly higher than that reported in the literature. The present study clearly shows that optimizing the amino acid profile by inclusion of a single crystalline amino acid (crystalline methionine) does not give the same protein utilization as that of a diet in which the amino acids are mainly protein bound. D ‐methionine was found to result in better protein utilization than L ‐methionine when measured as PPV.     

水稻氮肥管理的ORYZA－0模型之理论及验证

ＯＲＹＺＡ－０模型系统能分析氮在土壤－作物－大气复杂系统中的复杂行为，包括土壤供氮力、作物氮吸收和氮在器官间的分配、叶片氮转化太阳辐射为干物质的能力等，ＯＲＹＺＡ－０模型与Ｐｒｉｃｅ的规则系统优化程序结合，可以制订取得最大生物量或经济产量所需的优化氮管理方案。田间氮试验材料验证模型表明，ＯＲＹＺＡ－０模型推荐的氮肥应用曲线能真实地反映当地不同氮水平下的氮管理策略；文中还就模型参数的敏感性问题和模型的进一步发展提出了建设性建议。