Leukotrienes are Auto‐/Paracrine Factors in the Bovine Corpus Luteum: An In Vitro Study

The aim of this study was to determine leukotrienes (LTs) functions in the bovine corpus luteum (BCL) during the oestrous cycle. In steroidogenic CL cells we examined the effect of luteotropic [LH, prostaglandin E₂ (PGE₂)] and luteolytic (PGF_2α, cytokines) factors on: the levels of LTB₄ and C₄, the expression of 5‐lipoxygenase (LO), LT receptors type I (LTR‐I) and LTR‐II, and the effects of LTB₄ and C₄ stimulations on the levels of progesterone (P4), PGE₂, F_2α and nitric oxide (NO) metabolites. Both luteolytic and luteotropic factors stimulated 5‐LO expression on days 2–4 and 17–19 of the cycle. Leukotriene receptors type I expression increased after PGE₂ and tumour necrosis factor α with interferon γ (TNF/IFN) stimulation on days 2–4 of the cycle. Leukotriene receptor type II expression increased after PGE_2α and TNF/IFN stimulation on days 2–4 and 17–19 of the cycle, and LTR‐II expression on days 8–10 of the cycle was unchanged after cell stimulation with any factor. Leukotriene B₄ level increased after BSC incubation with luteotropic factors during all examined days of the cycle and after cytokine stimulation at early‐ and mid‐luteal stages, whereas luteolytic factors stimulated LTC₄ secretion over the entire cycle. Leukotriene B₄ stimulated P4 secretion at the mid‐luteal stage and stimulated NO secretion during all examined phases. Leukotriene B₄ stimulated PGE₂ secretion at the early‐ and mid‐luteal stage. Leukotriene C₄ inhibited P4 secretion at the mid‐ and regressing‐luteal stage, stimulated NO (entire cycle) and PGF_2α at mid‐ and regressing‐luteal phases. Leukotrienes modulate steroidogenic cells functions, depending on the stage of the cycle. Leukotriene B₄ plays a luteotropic role stimulating P4 and PGE₂ secretions; LTC₄ stimulates the secretion of luteolytic factors and enhances the luteolytic cascade within BCL.     

Wild fallow deer (Dama dama) as definitive hosts of Fasciola hepatica (liver fluke) in alpine New South Wales

To determine the extent to which wild deer are contributing in the transmission of Fasciola hepatica (liver fluke) livers from deer shot by hunters, farmers undertaking population control on their farms and vertebrate pest controllers were collected and frozen. The livers were later thawed, sliced and examined for the presence of adult flukes or evidence of past infection. Livers from 19 deer were examined (18 fallow [Dama dama] and one sambar [Rusa unicolor]). Seventeen of the fallow deer were animals collected on farms near Jindabyne, New South Wales. The remaining fallow deer was collected in the Australian Capital Territory and one sambar deer was collected in north-eastern Victoria. Nine of the 17 deer (53%) from the Jindabyne area were either infected with Fasciola hepatica (liver fluke) or had thickened bile ducts indicating past infection. Infection levels in the infected animals varied widely from 3 liver fluke to over 50 per liver. No sign of infection was present in the deer from the Australian Capital Territory or Victoria. Fallow deer are wide-spread in the Jindabyne area and their population is increasing. It is likely their contribution to the maintenance and distribution of F. hepatica to livestock in the Jindabyne area, and in other livestock rearing areas of south-eastern Australia, is important and increasing.     

Orientational disorder in solvent-free solid c70

The high-temperature structure of solvent-free C(70) has been determined with high-resolution x-ray powder difraction and electron microscopy. Samples crystallized from solution form hexagonal close-packed crystals that retain an appreciable amount of residual toluene, even after prolonged heating. Samples prepared by sublimation, which contain no detectable solvent, are primarily face-centered cubic with some admixture of a hexagonal phase. The relative volume of the hexagonal phase can be further reduced by annealing. The structures of both phases are described by a model of complete orientational disorder. The cubic phase contains an appreciable density of stacking faults along the [111] direction.     

A gonadotropin-releasing factor vaccine (Improvac) and porcine somatotropin have synergistic and additive effects on growth performance in group-housed boars and gilts

Two hundred and twenty-four pigs (112 boars, 112 gilts) housed in pens of seven pigs per pen were used in a 2 x 2 x 2 factorial design, with the factors of vaccination with a gonadotropin-releasing factor (GnRF) vaccine (Improvac; 0 or 2 mL at 13 and 17 wk of age), porcine somatotropin (pST; 0 or 5 mg/d from 17 wk of age), and gender. Pigs were weighed and feed intake was measured from 17 wk of age until slaughter at 21 wk of age. Body composition was estimated by dual-energy X-ray absorptiometry in two focus pigs per pen at 17 and 21 wk of age. Testes and ovary weights at slaughter were decreased by Improvac treatment (P < 0.001), but were not altered by pST treatment (P > 0.44). Daily gain was lower for gilts than boars (1,128 vs. 1,299 g/d, P < 0.001) and was increased by pST (1,172 vs. 1,255 g/d, P = 0.003) and Improvac (1,150 vs. 1,276 g/d, P < 0.001) treatments. Feed intake (as-fed basis) was lower in gilts than in boars (2,774 vs. 3,033 g/d, P = 0.002), was decreased by pST (3,037 vs. 2,770 g/ d, P = 0.002), and was increased by Improvac treatment (2,702 vs. 3,105 g/d, P < 0.001). As a result of the differences in feed intake and daily gain, feed conversion efficiency (gain:feed) was lower for gilts than for boars (0.403 vs. 0.427 P = 0.025), was improved by pST (0.385 vs. 0.452, P < 0.001), but was unchanged by Improvac treatment (0.423 vs. 0.410, P = 0.22). Carcass weight was lower in gilts than in boars (75.3 vs. 77.0 kg, P = 0.012), was unchanged by pST treatment (75.9 vs. 76.4 kg, P = 0.40), and was increased by Improvac treatment (75.1 vs. 77.2 kg, P = 0.003). Lean tissue deposition rate was lower in gilts than in boars (579 vs. 725 g/d, P < 0.001), was increased by pST (609 vs. 696 g/d, P < 0.001) and by Improvac treatment (623 vs. 682 g/d, P = 0.014). Fat deposition rate tended to be lower in gilts than in boars (214 vs. 247 g/d, P = 0.063), decreased by pST treatment (263 vs. 198 g/d, P < 0.001), and increased by Improvac treatment (197 vs. 264 g/d, P < 0.001). For pigs treated with both pST and Improvac, daily gain and lean tissue deposition rate was greater than for pigs that received either treatment alone, whereas fat deposition rate and feed intake did not differ from untreated control pigs. In conclusion, Improvac increased growth rate through increased lean and fat deposition, but concomitant use of Improvac and pST increased lean gain above either alone, while negating the increase in fat deposition in pigs treated with Improvac.     

Clinical diagnosis of schistosomiasis in sudanese cattle

This study was done in the White Nile Province to characterise the history and signs of naturally occurring Schistosoma bovis infection in cattle (Gorag). Necropsy and laboratory examinations were performed on 10 animals six to 30 months of age which were in poor condition. They were selected because of a history suggestive of schistosomiasis. All the animals showed some degree of S. bovis infection; eight had a moderate or heavy degree of infection. Also all had liver damage due to either past or active Fasciola gigantica infection. Although concurrent infection with these two trematodes is common an owner who diagnoses Gorag is most likely referring to the syndrome caused by S. bovis as being the major cause of the poor performance observed. Fasciolicide treatment may eliminate active fascioliasis as the principal damaging agent. Also differentiating signs of haemorrhagic diarrhoea, severely sunken eyed appearance and only moderate inappetence are common in animals with acute schistosomiasis.     

Comparison of ELISA and CFT assays for Chlamydophila abortus antibodies in ovine sera

OBJECTIVE: To compare the sensitivity and specificity of Chlamydophila abortus antibody assays, to find a suitable serological assay for testing sheep for export. DESIGN: Comparison of results from known positive and negative sheep populations. PROCEDURE: Fifty-five positive and fifty negative sera were analysed by four enzyme linked immunosorbent assays (ELISA), three using recombinant antigens based on the chlamydial polymorphic outer membrane proteins (POMP90-3, POMP90-4, POMP80-90) and one using a synthetic peptide based on chlamydial major outer membrane proteins (MOMP-P). They were also analysed by complement fixation tests (CFT) using crude antigens from chlamydia isolated from an Australian sheep, a Californian parakeet and a Texan turkey. Assay sensitivity and specificity were expressed as point estimates and 95% confidence intervals. Results were compared using McNemar's test for paired samples. RESULTS: ELISA sensitivity ranged from 70 to 98% and complement fixation test sensitivity from 60 to 96%; with POMP90-3 > POMP90-4 > CFT (parakeet) > CFT (turkey) > POMP80-90 > MOMP-P > CFT (sheep). There was no significant difference from POMP90-3 to POMP80-90 (P > 0.05). ELISA specificity ranged from 88 to 100% and CFT specificity was 100% for all three antigens; with CFT and POMP90-4 > MOMP-P > POMP80-90 > POMP90-3. There was no significant difference from CFT to POMP80-90 (P > 0.05). Changing the CFT cut-off from 1:32 to 1:4 substantially reduced the specificity with little improvement in sensitivity. CONCLUSION: Assays using POMP90-4, POMP80-90, CFT (parakeet) and CFT (turkey) had equivalent sensitivity and specificity; none of the ELISAs were more specific than any CFT. The POMP80-90 ELISA is recommended as an alternative to CFT (parakeet) but as its specificity is not ideal the search for a more specific assay should continue.     

Effects of age on the electroencephalographic response to castration in lambs anaesthetised using halothane in oxygen

AIM: To use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex to the noxious stimulus of castration varied with age in lambs.

METHODS: Two groups of East Friesian lambs were selected according to age; the mean age of the younger group (n=21) was 12 (SD 2) days and the older group (n=20) was 29 (SD 1) days. Anaesthesia was induced via mask using 4% halothane in oxygen, and maintained using 1.5% halothane in oxygen at a flow rate of 4 L/min. Once a stable plane of anaesthesia had been achieved, data collection of EEG and electrocardiographic (ECG) readings commenced, and the lambs were castrated 15 min later, using rubber rings. Median and 95% spectral edge frequencies (F95) and total EEG power (ptot) were derived from data from the EEG.

RESULTS: Following castration, there was an increase in the median frequency (F50) in the younger lambs (p=0.002), and an increase in ptot in both groups (p=0.05), which was of greater magnitude in the older lambs. There were no significant changes in the F95. Both younger and older lambs exhibited a transient bradycardia (p=0.001 and p=0.01, respectively).

CONCLUSIONS: These differences in the cortical response between the two groups suggest that 2-week-old lambs undergo a qualitatively different perception of the noxious stimulus of castration compared to 4-week-old lambs.