Electron microscope observations of Ceratocystis ulmi-induced tylosis development in Ulmus1

Electron microscope observations of Ceratocystis ulmi-induced tylosis development in 3 species of elm were made during the first 2 weeks after artificial inoculation. Tylosis forming from both ray and vasicentric parenchyma occluded vessels adjacent to those containing the fungus conidia within one day after inoculation. The expanding protoplast forced the intact vessel-parenchyma “pit membrane” and protective layer through the pit into the vessel lumen. Cell organization during this expansion is discussed. The observations on tylosis development for the 3 elms used were identical.     

The effects of different maternal dietary iodine concentrations on Japanese quail II. Thyroid function in embryos and hatchlingsi

Embryos (day I4 of the 16.5 day incubation period) and I day old chicks of Japanese quail (Coturnix japonica) were used to study the effects of egg I on thyroid development. The maternal diets were supplemented with 0–1200 μg I/kg of purified diet. Thyroid function, of embryos and chicks (before feeding), adapted to a wide range of egg I availability.We measured body weights, thyroid weights, thyroidal ¹²⁵I uptakes, stable I concentrations in thyroid glands and triiodothyronine (T₃) and thyroxine (T₄) concentrations in the serum.With low egg I (maternal diets with <50 μg I/kg) embryonic and chick thyroid glands were hypertrophied, thyroidal I content was very low and thyroidal radioiodine uptakes were high. Serum hormone concentrations were not significantly different from those of embryos and chicks from eggs with higher I contents. Thyroid weights were lowest in young from eggs of hens on the 150 μg I/kg diet, and the other variables studied also indicated this maternal diet provided sufficient egg I for the thyroid function of embryos and hatchlings.With high egg I (maternal diets with 300–1200 μg I/kg) thyroidal radioiodine uptakes were low but thyroidal I incorporation was related to egg I content. Serum hormone concentrations were not significantly altered by high I availability except that serum T₄ concentrations differed in a comparison of the extremes (0 vs 1200 μg I/kg in the maternal diet). As expected, from the consistency of serum hormone concentrations, embryonic growth was not affected by the I content of the eggs.In agreement with earlier studies on quail hens, our results indicate that feed supplementation of 150 μg I/kg is sufficient to meet needs without requiring alterations in thyroid function to maintain serum hormone concentrations. Developing thyroid glands adapt effectively to egg I concentrations of 0.2 to 4.1 μg I/g yolk which result from maternal diets with 0–1200 μg I/kg.     

Detection of feline coronavirus infection in captive cheetahs (Acinonyx jubatus) by polymerase chain reaction.

Feline coronavirus genetic elements were detected by polymerase chain reaction from blood, fecal samples, and effusive fluid collected from 33 cheetahs in the U.S.A. Feline coronavirus-specific serum antibodies were also measured by indirect immunofluorescence. Ten cheetahs were positive for viral shedding by polymerase chain reaction, whereas 13 were seropositive by immunofluorescence. Results of serology did not consistently correlate with shedding of virus, and the capture antigen used for detection of feline coronavirus-specific antibodies had a significant impact on results. Testing of samples from one population over a 1-yr period indicated chronic infection in some animals. These relatively healthy carrier animals were a source of virus for contact animals. Screening programs in cheetah populations for feline coronavirus infection may be most reliable if a combination of serologic analysis and viral detection by polymerase chain reaction is used.     

Valine partitioning and kinetics between the gastrointestinal tract and hind limbs in lambs with an adult Trichostrongylus colubriformis burden

Intestinal parasitic infection increases the demand for AA because of increased protein synthesis in the intestine and increased luminal losses of AA, and these increased demands may be supported by increased mobilization of AA from the skeletal muscles. Two experiments were conducted to determine the effects of parasitic infection on valine kinetics within the gastrointestinal tract and hind limbs of lambs fed fresh forages. On d 1, lambs were given 6,000 stage-3 Trichostrongylus colubriformis larvae per day for 6 d (n = 6) or kept as parasite-free controls (n = 6) and fed fresh lucerne (Medicago sativa; Exp. 1) or fresh sulla (Hedysarum coronarium; Exp. 2). On d 48, valine kinetics within the mesenteric- (MDV) and portal-drained viscera (PDV) and hind limbs were obtained by carrying out concurrent infusions of para-amminohippuric acid into the mesenteric vein and indocyanin green into the abdominal aorta (for blood flow), and [3,4-(3)H]valine into the jugular vein and [1-(13)C]valine into the abomasum for 8 h (for kinetics). During the infusions, blood was collected from the mesenteric and portal veins and from the mesenteric artery and vena cava, and plasma was harvested. After the 8-h infusion, lambs were euthanized, ileal digesta were collected, and tissues were sampled from the intestine and muscle (biceps femoris). Tissues, digesta, and plasma were analyzed for valine concentration, specific radioactivity, and isotopic enrichment. In both experiments, intestinal worm burdens on d 48 were greater in parasitized lambs (P = 0.0001 and 0.003). In Exp. 1, parasitic infection increased (P = 0.03) the total valine irreversible loss rate (ILR) in the MDV and PDV. In Exp. 2, luminal ILR of valine in the MDV was reduced (P = 0.01); however, ILR of valine in the PDV was unaffected. Despite these changes within the MDV and PDV, parasitic infection did not affect the ILR of valine within the hind limbs, and valine transport rates were largely unchanged. We suggest that the increased mobilization of AA from the hind limbs that might have occurred in the early phase of inflammation was no longer required when the parasitic infection was established. The MDV and PDV data may indicate that the non-MDV parts of the PDV play an important role in this adaptation, which warrants further study.     

Multiple rotation yields for intensively managed plantations in the Amazon basin

Jari Celulose S. A. is a Brazilian-owned industrial enterprise located along the Jari River (the first major south-flowing tributary of the Amazon). The company produces bleached kraft pulp for international and domestic sales. The raw material of this pulp production comes from the 75,000 ha of intensively managed plantations of Pinus caribaea (Morelet) and Eucalyptus spp. harvested on 10- and 6-year rotations, respectively. All currently active Jari plantations were converted from primary forest between 1968 and 1982. Silvicultural practices have been modified over successive rotations, including plantation species changes, increased intensity of site preparation, fertilization, and chemical weed control. A review of data from the early 1970s to present indicates an increase in productivity over successive rotations and several plantation locations and soil types. The reasons for this improvement are primarily related to the higher levels of silvicultural inputs and dramatic genetic gains. The long-term sustainability of this productivity is discussed in terms of current and future inputs. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of condensed tannins on egg hatching and larval development of Trichostrongylus colubriformis in vitro

The effects of condensed tannins extracted from seven forages on the viability of the eggs and first stage (L1) larvae of the sheep nematode Trichostrongylus colubriformis were evaluated in in vitro assays. The extracts of condensed tannins were obtained from Lotus pedunculatus (LP), Lotus corniculatus (LC), sulla (Hedysarum coronarium), sainfoin (Onobrychus viciifolia), Dorycnium pentaphylum (DP), Dorycnium rectum (DR) and dock (Rumex obtusifolius). Extracts containing 200 to 500 microg/ml reduced the proportion of eggs that hatched. The larval development assay was used to evaluate the effect of the extracts on the development of either eggs or L1 larvae to L3 infective larvae. Development was allowed to proceed for seven days by which time the larvae in control incubations had reached the infective L3 stage. Extracts containing 200 microg/ml from LP, DP, DR or dock prevented egg development, and only 11, 8 and 2 per cent of the eggs developed to L3 larvae with extracts from LC, sulla and sainfoin, respectively. When the concentration was 400 microg/ml no eggs developed to L3 larvae. The addition of the extracts after hatching also inhibited the development of L1 to L3 larvae; 200 microg/ml extracted from LP, LC, sulla, sainfoin, DP, DR and dock resulted in only 14, 18, 17, 15, 14, 16 and 4 per cent of L1 larvae developing to the L3 stage compared with 85 per cent for controls, and 400 microg/ml further reduced the development of L1 larvae. Statistical analyses showed that when the extracts were added before hatching they were significantly (P<0.001) more effective at inhibiting the larval development than when they were added after hatching. The condensed tannins from dock had the greatest inhibitory effect on egg development followed by the tannins from DR, sainfoin, DP, LP, sulla and LC.     

Prevalence of Salmonella contamination in market-ready geese in Manitoba

Salmonella contamination is a major problem in the poultry industry, but no data are available on the prevalence in geese. From two slaughter facilities in Manitoba, 130 carcass rinsings and 315 cloacal swabs from a total of 17 flocks of domestic geese were examined for salmonellae. Sixty percent of the carcass rinsings and 18.4% of the cloacal swabs were positive. Most of the isolates were serotyped, and some analysis of the results is presented. Three culture media were compared, and a modified dulcitol brilliant-green novobiocin medium was found to be more selective than brilliant-green and brilliant-green sulfa agars.     

Hepatic 5'-deiodination in chickens from lines selected for high and low body weight and their F1 cross

1. Assay conditions for measuring hepatic 5'-deiodinase (5'D) activity at initial velocity, using reverse T3 as substrate, have been validated for adult chicken liver. 2. The characteristics of hepatic 5'D activity in adult chickens from lines selected for high (HW) and low (LW) juvenile body weight are similar to those in mammals and in the other birds that have been investigated. 3. Chickens from the HW line have significantly higher specific activity of hepatic 5'D, and thus potentially higher T3 production, than those from either the LW line or the F1 cross (HL) between the HW and LW lines.     

Effect of condensed tannins extracted from four forages on the viability of the larvae of deer lungworms and gastrointestinal nematodes

The inhibitory activity of condensed tannins extracted from four forage legume plants were evaluated by using a larval migration inhibition assay. The first (L1) and third (L3) stages of deer lungworm (Dictyocaulus viviparus), and the third stage (L3) of deer gastrointestinal nematodes were incubated with tannins extracted from Lotus pedunculatus, Lotus corniculatus, sulla (Hedysarum coronarium) and sainfoin (Onobrychus viciifolia). The tannins extracted from all the forages had inhibitory activity as measured by their ability to paralyse the larvae and inhibit them from passing through sieves. At the highest concentration used (1200 microg/ml) the tannins extracted from sainfoin had the highest activity against ensheathed L1 lungworm larvae (58 per cent), followed by L. pedunculatus (45 per cent), sulla (42 per cent) and L. comiculatus (35 per cent) when the larvae were incubated at 37 degrees C. The same trend, but with lower activities, was observed when the larvae were incubated at 22 degrees C. Anthelmintic activity against L3 lungworm larvae was evaluated by measuring the death rate of ensheathed L3 larvae after incubation with condensed tannins for two, 24 and 48 hours at room temperature (22 degrees C). The death rate was significantly higher (P<0.001) after 48 hours incubation than after two hours or 24 hours, and significantly higher (P<0.001) after 24 hours than after two hours incubation. Condensed tannins from sainfoin had the highest inhibitory activity followed by L. pedunculatus, sulla and L. comiculatus. The tannins from sainfoin also had the highest activity against L3 larvae of gastrointestinal nematodes, followed by L. pedunculatus, sulla and L. comiculatus. Exsheathed larvae of gastrointestinal nematodes were significantly more susceptible to the action of the tannins than ensheathed larvae.