Differential effects of the endocrine-disrupting compounds bisphenol-A and octylphenol on gonadotropin secretion, in prepubertal ewe lambs

This study examined the effects of long-term exposure to the endocrine-disrupting compounds (EDCs) Bisphenol-A (BPA) and Octylphenol (OP) on gonadotrophin secretion in pre-pubertal female sheep. Four-week-old, female lambs were randomly allocated to four groups (n=6), and twice each week treated with i.m. injections of either corn oil (vehicle controls), diethylstilbestrol (DES; 0.175mg/kg), BPA (3.5mg/kg) or OP (3.5mg/kg). After 5 weeks of treatment, animals were ovariectomized (ovx) and ovary weights recorded. Two weeks later, blood samples were collected from lambs every 15min for 6h, for LH pulse analysis. Animals were then euthanased and adrenal and kidney weight recorded. An age-related increase in tonic LH secretion was noted in Control, BPA- and OP-treated lambs, but was absent in DES-treated lambs. Following ovx, LH secretion increased in all except DES-treated lambs; FSH concentrations increased in all groups. BPA and DES significantly suppressed LH pulse frequency (C: 6.7+/-0.3pulses/6h, DES: 1.5+/-0.8pulses/6h, BPA: 2.3+/-0.8pulses/6h) and amplitude (C: 7.1+/-1.0ng/ml, DES: 1.9+/-0.6ng/ml, BPA: 1.6+/-0.4ng/ml). OP had no effect on LH secretion (Frequency: 5.8+/-0.5pulses/6h, amplitude: 8.0+/-2.0ng/ml). Ovary weight was similar among all groups. Results show that chronic in vivo exposure of prepubertal female lambs to BPA, at levels lower than those reported previously, can have significant effects on LH secretion that are comparable to those seen following exposure to the known xenoestrogen, DES. Exposure to an equal dose of the EDC OP, over the equivalent period of time was without effect on gonadotropin secretion in the prepubertal ewe lamb. These results indicate that exposure of prepubertal female lambs to the EDC BPA can induce significant effects on gonadotropin secretion, the potential long-term effects of exposure and the effects of these changes on reproductive performance and efficacy, therefore, merit further study.     

Detection of genes encoding virulence factors and bacteriocins in fecal enterococci of poultry in Portugal

Seventy-six Enterococcus isolates (43 E. faecalis, 30 E. faecium, two E. durans, and one E. hirae) recovered from fecal samples of poultry in a slaughterhouse (one isolate per fecal sample and one fecal sample per lot of animals) were studied for bacteriocin production and for the presence of genes encoding bacteriocins and virulence factors. The presence of genes encoding virulence factors (cpd, geE, fsr, ace, agg, and esp) and bacteriocins (entA, entB, entP, entQ, entAS-48, entL50A/B, cyl, and bac31) were studied by polymerase chain reaction in all enterococci. At least two virulence genes were detected in all 43 E. faecalis isolates, cpd and gelE being the most frequently detected genes (97.7%) followed by ace (62.8%), agg (39.5%), fsr (27.9%), and esp (2.3%). No virulence genes were detected in the other enterococcal species with the exception of one E. faecium and one E. durans isolates that harbored the gelE gene. Antimicrobial activity against eight indicator bacteria (including Listeria monocytogenes) was assayed in the enterococci, and 23 (30.3%) showed inhibitory activity against L. monocytogenes, the other 22 enterococci showing activity against indicator bacteria other than L. monocytogenes. Only the entA, entB, and cyl genes were detected in our study (entA + entB in nine E. faecium isolates and the cyl gene in seven E. faecalis isolates). A wide variety of virulence genes have been detected in fecal E. faecalis isolates from poultry, but not in the other enterococcal species. However, the presence of known bacteriocin structural genes is associated more with the E. faecium species.     

Brucella abortus detection by PCR assay in blood, milk and lymph tissue of serologically positive cows

Brucellosis is a highly infectious disease which is diagnosed using serological and microbiological methods. The objective of this study was to assess the viability of using conventional and real-time PCR assays as potential diagnostic tools for the detection of Brucella abortus in naturally infected cows. PCR assays that amplify various regions of the Brucella genome, IS711 genetic element, 31kDa outer membrane protein and 16S rRNA, were optimised using nine known Brucella strains. Real-time PCR was used to examine the detection efficiency of the IS711 assay which was estimated at 10 gene copies. Milk, blood and lymph tissue samples were collected from naturally infected animals. B. abortus was not detected in blood samples collected from naturally infected cows by conventional or real-time PCR, but was detected in a proportion of the culture-positive milk (44%) and lymph tissue (66% - retropharyngeal, 75% - supramammary) samples by the same methods. There was no difference between PCR and bacteriological detection methods. It is unlikely that conventional or real-time PCR will supersede current diagnostic methods for detection of B. abortus in clinical samples.     

Effect of high-pressure-moderate-temperature processing on the volatile profile of milk

The effects of high hydrostatic pressure on volatile generation in milk were investigated in this study. Raw milk samples were treated under different pressures (482, 586, and 620 MPa), temperatures (25 and 60 degrees C), and holding times (1, 3, and 5 min). Samples submitted to heat treatments alone (25, 60, and 80 degrees C for 1, 3, and 5 min) were used for comparison. Trace volatile sulfur compounds were analyzed using solid-phase microextraction (SPME) and gas chromatography (GC) with pulsed-flame photometric detection (PFPD), whereas the rest of the volatile compounds were analyzed using SPME-GC with flame ionization detection (FID). Multivariate analysis of variance (MANOVA) and principal component analysis (PCA) were used to study the effect of pressure, temperature, and time on volatile generation. Relative concentration increases of 27 selected volatile compounds were compared to an untreated sample. It was found that pressure, temperature, and time, as well as their interactions, all had significant effects (P < 0.001) on volatile generation in milk. Pressure and time effects were significant at 60 degrees C, whereas their effects were almost negligible at 25 degrees C. The PCA plot indicated that the volatile generation of pressure-heated samples at 60 degrees C was different from that of heated-alone samples. Heat treatment tended to promote the formation of methanethiol, hydrogen sulfide, methyl ketones, and aldehydes, whereas high-pressure treatment favored the formation of hydrogen sulfide and aldehydes.     

Inhibition of hemoglobin- and iron-promoted oxidation in fish microsomes by natural phenolics

Natural phenolic antioxidants have been tested in hake (Merluccious merluccious) microsomes as inhibitors of lipid oxidation promoted by fish muscle prooxidants: hemoglobin (Hb), enzymatic NADH-iron and nonenzymatic ascorbate-iron. The phenolics selected were as follows: (a) a grape phenolic extract (OW), (b) a fraction (IV) with isolated grape procyanidins with a medium-low degree of polymerization and galloylation percentage, (c) hydroxytyrosol obtained from olive oil byproducts, and (d) a synthetic phenolic antioxidant, propyl gallate. All compounds delayed lipid oxidation activated by Hb, enzymatic NADH-iron, and nonenzymatic ascorbate-iron, excluding hydroxytyrosol that was not an effective antioxidant on oxidation promoted by nonenzymatic iron. The relative antioxidant efficiency was independent of the prooxidant system, IV > propyl gallate > OW > hydroxytyrosol, and showed a positive correlation with their incorporation into microsomes (p < 0.05). The reducing capacity or ability for donating electrons and the chelating properties may also contribute to the antioxidant activity of phenolics, although these factors were less decisive than their affinity for incorporating into the microsomes. Conversely, the inhibition of Hb oxidation by phenolics and their polarity did not seem to play an important role on antioxidant mechanism. These results stressed the importance of incorporating the exogenous antioxidants into the membranes where are located key substances for fish lipid oxidation (highly unsaturated phospholipids, iron-reducing enzymes, and endogenous alpha-tocopherol).     

Hemodynamic effects of methylprednisolone acetate administration in cats

OBJECTIVE: To investigate the mechanisms by which corticosteroid administration may predispose cats to congestive heart failure (CHF). ANIMALS: 12 cats receiving methylprednisolone acetate (MPA) for the treatment of dermatologic disorders. PROCEDURE: The study was conducted as a repeated-measures design. Various baseline variables were measured, after which MPA (5 mg/kg, IM) was administered. The same variables were then measured at 3 to 6 days and at 16 to 24 days after MPA administration. Evaluations included physical examination, systolic blood pressure measurement, hematologic analysis, serum biochemical analysis, thoracic radiography, echocardiography, and total body water and plasma volume determination. RESULTS: MPA resulted in a substantial increase in serum glucose concentration at 3 to 6 days after administration. Concurrently, RBC count, Hct, and hemoglobin concentration as well as serum concentrations of the major extracellular electrolytes, sodium and chloride, decreased. Plasma volume increased by 13.4% (> 40% in 3 cats), whereas total body water and body weight slightly decreased. All variables returned to baseline by 16 to 24 days after MPA administration. CONCLUSIONS AND CLINICAL RELEVANCE: These data suggest that MPA administration in cats causes plasma volume expansion as a result of an intra to extracellular fluid shift secondary to glucocorticoid-mediated extracellular hyperglycemia. This mechanism is analogous to the plasma volume expansion that accompanies uncontrolled diabetes mellitus in humans. Any cardiovascular disorders that impair the normal compensatory mechanisms for increased plasma volume may predispose cats to CHF following MPA administration.     

Differential induction of pathogenesis-related proteins in banana in response to Mycosphaerella fijiensis infection

Black leaf streak or “black Sigatoka” is one of the most important diseases affecting bananas and plantains worldwide. Very few studies have been published on the host-pathogen interaction of this pathosystem, particularly at the molecular level. The aim of this work was to analyze, under controlled conditions, the enzyme activity of peroxidase (POX), phenylalanine ammonia lyase (PAL), β-1, 3-glucanase (GLU) and chitinase (CHI) as well as the production of H₂O₂ in banana plants infected with Mycosphaerella fijiensis. Defence responses were examined and compared in a resistant (Calcutta 4) and a susceptible (Williams) cultivar. Plants were inoculated and tested for enzyme activity at 0, 6, 12, 18, 24, 48 and 72?h after infection (HAI) and 6, 9, 12, 15 and 18?days after inoculation (DAI). A rapid induction of PAL, POX and GLU was observed in the resistant cultivar at 6–18 HAI as well as H₂O₂ production at 72 HAI. In contrast, in the susceptible cultivar, induction of these enzymes was only observed from 6 DAI. These results suggest that the first 72 HAI are important in determining the response of the host to the disease. Further studies characterizing banana responses to M. fijiensis at the early stages of the infection are necessary in order to better understand this host-pathogen interaction.     

Detection of Aphanomyces invadans and epizootic ulcerative syndrome in the Murray‐Darling drainage

Epizootic ulcerative syndrome was diagnosed, and the presence of Aphanomyces invadans confirmed, from an outbreak of clinical disease in wild‐caught bony bream (Nematalosa erebi) from the Darling River near Bourke, in New South Wales, Australia, during 2008. This confirms a significant extension of the agent beyond its historical range.     

Increasing energy and lysine in diets for growing-finishing pigs in hot environmental conditions: consequences on performance, digestibility, slurry composition, and gas emission

The influence of dietary nutrient concentration on growth performance, manure composition, and gas emission was studied in pigs in hot environmental conditions. A total of 64 intact males and 64 females [(Landrace × Large White) × Pietrain] weighing 63.1 ± 9.7 kg were divided into 2 dietary treatments: high (HD: 14.39 MJ of DE/kg and 1.11% Lys) and low (LD: 13.97 MJ of DE/kg and 1.01% Lys) in energy and Lys contents. Pigs were allocated to 32 split-sex pens with 4 pigs/pen and 16 pens/treatment. Average productive performance was recorded for 41 d (phase 1). After phase 1, 12 females of 103.3 ± 3.15 kg (6 per treatment) were selected and housed individually, and feces and slurry were collected during 3 and 4 consecutive days, respectively, to calculate nutrient digestibility and measure gas emissions (phase 2). For gas emission measurements, slurry was pooled by treatment and stored for 76 d. Initial composition of slurry and pH were analyzed. Maximum and minimum temperatures registered in the barn throughout the growing period were 35.1 and 18.1°C, respectively. Animals fed the HD diet grew more efficiently than pigs fed the LD diet (G:F, 0.43 vs. 0.40; SEM = 0.01; P < 0.05). Fat digestibility was greater in HD compared with LD pigs (88.0 vs. 84.9%; SEM = 0.9; P < 0.05). Slurry from pigs fed the LD diet showed greater DM, OM, total N, and VFA contents than slurry from pigs fed the HD diet. Cumulative NH(3), CO(2), and especially CH(4) emissions were greater in the HD slurry compared with the LD slurry (192.4 vs. 210.g of NH(3)/m(3); 2,712 vs. 3,210 g of CO(2)/m(3); 1,502 vs. 2,647 mL of CH(4)/kg of OM). Increasing feed density in the present study led to a more efficient growth, a decreased nutrient concentration in the slurry, and a greater gas emission.