Genetic Variation of Ethiopian Mustard (Brassica carinata A. Braun) Germplasm in Western Canada

Information on genetic diversity and genetic relationships among genotypes of Brassica carinata is currently limited. The objectives of this study were to evaluate patterns and levels of genetic diversity in B. carinata based on amplified fragment length polymorphisms (AFLP) as compared with Brassica juncea and Brassica nigra, and to evaluate agronomic and seed quality data for plants grown in the field in western Canada. A total of 296 AFLP bands were generated from four primer pair combinations and scored for presence/absence in 66, 20 and 7 accessions of B. carinata, B. juncea and B. nigra, respectively. B. carinata was less genetically diverse than the other two species. Differences in diversity were evident in the proportion of polymorphic loci within each species: 23, 35 and 50% for B. carinata, B. nigra and B. juncea, respectively. Pair-wise similarity measures based on the Jaccard coefficient were highest among accessions of B. carinata and showed the narrowest range: 0.911 (0.810–0.981) compared to B. nigra: 0.569 (0.438–0.660) and B. juncea: 0.715 (0.345–0.951). AFLP-based genetic distance information can be used by plant breeders to select diverse genotypes. AFLPs are also useful for fingerprinting cultivars and two primer pair combinations were sufficient to uniquely identify all the accessions of B. carinata. More variation among accessions was identified in the agronomic trial than had previously been described in studies of B. carinata in western Canada, but the data were too limited to draw conclusions regarding specific accessions. Overall, the findings were in agreement with other published work describing the favourable agronomic potential of this species.     

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. I. Prevalence and morphological description of gross lung lesions

The prevalence and pathomorphology of gross lung lesions were studied in 855 slaughter weight pigs from 9 selected herds in south-eastern Norway. Pneumonic or pleuritic lesions were found in 84% of the lungs, ranging from 37% in the least affected herd to 97% in the one most affected. Bronchopneumonia indicative of a primary Mycoplasma hyopneumoniae infection was found in 70% of the lungs, ranging from 9% to 82% in the individual herds. The amount of bronchopneumonic lesions in individual lungs ranged from 0 to 69%, with an average of 7.8%. Pleuropneumonia indicative of Actinobacillus (Haemophilus) pleuropneumoniae infection was found in 29% of the lungs ranging from 0 in the least affected herd to 58% in the most affected. Diffuse pleuritis was found in 41% of the lungs and the prevalence ranged from 4% to 63%.     

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. IV. Bacteriological findings in chronic pneumonic lesions.

A total of 855 pig lungs were collected at slaughter and evaluated macroscopically. Bacteriological examinations were carried out on tissue samples from chronic pleuropneumonic lesions (n = 196) and from chronic bronchopneumonic lesions with suppuration (n = 14). Samples from normal lung tissue (n = 22) were also included. Pasteurella multocida was isolated from 54%, Actinobacillus (Haemophilus) pleuropneumoniae from 11%, and Streptococcus spp. from 14% of the pneumonic lesions, respectively. From normal lung tissue P. multocida was isolated from 3 (14%) of the samples, A. pleuropneumoniae was not recovered and streptococci were isolated from only 1 (5%) of these samples. The above mentioned bacterial species were recovered either in pure cultures or mixed with various other microbes. A total of 109 P. multocida strains were further characterized by capsular serotyping and testing for production of dermonecrotic toxin. Ninety-nine (91%) of the strains were capsular type A 10 (9%) were type D. Out of the type A and the type D strains 94% and 90% were toxigenic, respectively. Most of the A. pleuropneumoniae strains were serotype 2. Strains of serotypes 1 and 7 were also identified. The majority of the streptococci were identified as either Streptococcus suis or Streptococcus dysgalactiae. Actinomyces pyogenes was isolated from 14% of the lesions and anaerobic bacteria from 18%, respectively. The significance of the various bacterial species in relation to the development of chronic pneumonic lesions is discussed. Special attention is paid to P. multocida, and it is concluded that this bacterial species is probably of importance for the development of both types of chronic pneumonias.     

Selenium Concentrations in Tissues and Eggs of Growing and Laying Chickens Fed Sodium Selenite at Different Levels

Growing and laying chickens were fed graded levels of selenium in the form of sodium selenite. One day old Norwegian bred broiler chickens and 20 weeks old Norwegian bred White Leghorn chickens were divided into 5 groups each and fed a basal diet supplemented with 0, 0.1, 1.0, 3.0 or 6.0 μg Se/g for 6 and 31 weeks, respectively. At the end of the experiments significantly higher concentrations of selenium were found in the groups fed 1.0, 3.0 and 6.0 μg Se/g diet compared to the control group. Correspondingly higher concentrations of selenium were found in egg samples. The increase in egg yolk selenium was much higher than in egg white. Significant correlations were found between the amounts of selenium added to the ration and the selenium concentrations in liver, kidney, breast muscle, egg white, yolk and homogenized egg. There were no differences in body weight gain and egg production between the groups. A possible positive contribution to animal and human health of selenium supplementation of animals’ diet above the required level is discussed.     

Porcine salmonellosis. 3. Production of fibrinous colitis by intravenous injections of a mixture of viable cells of salmonella cholerae-suis and disintegrated cells of the same agent, or hemolytic Escherichia coli

Hemorrhagic necrosis of the gastric and colonic mucosa with capillary thrombosis were induced in pigs experimentally infected with Salmonella cholerae-suis when an additional intravenous supply of disintegrated cells of Salmonella cholerae suis or hemolytic Escherichia coli was administered. Except for the gastrointestinal lesions, the necropsy findings were almost identical with the picture found in acute septicemic salmonellosis. The gastrointestinal changes were interpreted as a special gastroenteric effect of endotoxins of Gramnegative bacteria during the development of septicemic salmonellosis.     

Transmission of Phytophthora ramorum in Mixed-Evergreen Forest in California

ABSTRACT During 2001 to 2003, the transmission biology of Phytophthora ramorum, the causal agent of sudden oak death, was studied in mixedevergreen forest, a common forest type in northern, coastal California. Investigation of the sources of spore production focused on coast live oak (Quercus agrifolia) and bay laurel (Umbellularia californica), dominant hosts that comprised 39.7 and 46.2% of the individuals at the study site, respectively. All tests for inoculum production from the surface of infected coast live oak bark or exudates from cankers were negative. In contrast, sporangia and chlamydospores were produced on the surface of infected bay laurel leaves. Mean number of zoospores produced from infected bay laurel leaves under natural field conditions during rainstorms was 1,173.0 +/- SE 301.48, and ranged as high as 5,200 spores/leaf. P. ramorum was recovered from rainwater, soil, litter, and streamwater during the mid- to late rainy season in all 3 years of the study. P. ramorum was not recovered from sporadic summer rains or soil and litter during the hot, dry summer months. Concentrations of inoculum in rainwater varied significantly from year to year and increased as the rainy season progressed for the two complete seasons that were studied. Potential dispersal distances were investigated for rainwater, soil, and streamwater. In rainwater, inoculum moved 5 and 10 m from the inoculum source. For soil, transmission of inoculum was demonstrated from infested soil to bay laurel green leaf litter, and from bay laurel green leaf litter to aerial leaves of bay laurel seedlings. One-third to one-half of the hikers tested at the study site during the rainy season also were carrying infested soil on their shoes. In streamwater, P. ramorum was recovered from an unforested site in pasture 1 km downstream of forest with inoculum sources. In total, these studies provide details on the production and spread of P. ramorum inoculum in mixed-evergreen forest to aid forecasting and managing disease transmission of this environmentally destructive pathogen.     

Comparison of follicular and oocyte development and reproductive hormone secretion during the ovulatory period in Hungarian native breed, Mangalica, and Landrace gilts

Only a very small amount of physiological data is available about the low fertility (mean litter size is 5.7+/-0.8) of Hungarian native breed, Mangalica (M), sows. The aim of the present paper is to reveal the differences in preovulatory follicle development and intrafollicular oocyte maturation between M and Landrace (L) gilts, with special reference to the peri- and postovulatory secretion and peripheral concentrations of estradiol-17beta (E2), progesterone (P4), and luteinizing hormone (LH). The number of preovulatory follicles was 6.8+/-1.4 and 19.6+/-6.6 in M and L gilts, respectively. A lower degree of cumulus expansion and a lower percentage of mature oocytes (TI/M II) was noted in M. Higher LH and E2 peak levels, a longer E2 to LH peak interval, and lower embryo survival was confirmed. Interestingly, despite the lower number of corpora lutea, a higher peripheral blood level of P4 was shown in M than in L gilts. Both diminished follicular development and protracted oocyte maturation may be involved in low fecundity in M, and the present findings may explain these reproductive phenomena.     

Alteration of reproductive hormone levels in pregnant sows induced by repeated ACTH application and its possible influence on pre- and post-natal hormone secretion of piglets

Prenatal stress has been seen as a reason for reproductive failures in pig offspring mostly originated or mediated by changed maternal functions. Experiments were conducted in pregnant gilts (n=32) to characterize effects of elevated maternal glucocorticoids on the secretion of reproductive hormones (LH, progesterone) during the 1st (EXP 1), 2nd (EXP 2) and 3rd (EXP 3) trimester of pregnancy (TP). Transiently elevated cortisol release was repeatedly achieved by application of 100 IU adenocorticotropic hormone (ACTH) (Synacthen Depot) six times every second day beginning either on day 28 (EXP 1), day 49 (EXP 2) or day 75 of pregnancy (EXP 3). Glucocorticoid concentrations were examined in umbilical blood vessels of fetuses which mothers were subjected to ACTH at 2nd and 3rd TP (EXP 4). Furthermore, the pituitary function of newborn piglets of EXP 2 was checked by a LH-RH challenge test. In sows, LH concentrations were at low basal level (0.1-0.2 ng/ml) but with pulsatory release pattern during each TP. The number of LH pulses/6 h (LSM +/- SE) of saline treated Controls increased with ongoing pregnancy and decreased to the 3rd TP (1.3 +/- 0.2 in EXP 1 vs. 2.0 +/- 0.1 in EXP 2 vs. 1.4 +/- 0.1 in EXP 3, p<0.05). After ACTH treatment the number of LH pulses left unchanged in Experiments 1 and 2 (1.3 +/- 0.2 and 1.5 +/- 0.1) and decreased in EXP 3 (0.8 +/- 0.2, p<0.05). Differences (p<0.05) were obtained comparing the LH pulse number of ACTH and saline treated sows at the 2nd and 3rd TP. Moreover, areas under the curve (AUC) of each LH pulse and of LH over baseline were significantly reduced by treatment. Levels of progesterone increased (p<0.05) for 150 to 170 min after each ACTH application both in EXP 1 and EXP 2, but not in EXP 3. The mean progesterone concentration was different between trimesters, and ACTH and Controls (1st TP: 30.0 +/- 0.9 and 24.4 +/- 0.7 ng/ml; 2nd TP: 35.5 +/- 0.9 and 29.1 +/- 1.0 ng/ml; 3rd TP: 13.6 +/- 0.2 and 13.1 +/- 0.1 ng/ml; p<0.05). In fetuses (n=87) recovered 3 h after ACTH or saline (EXP 4), the plasma cortisol concentrations were significantly increased in umbilical vein (93.7 +/- 5.5 vs. 47.0 +/- 5.3 nmol/l) and artery (95.7 +/- 5.4 vs. 66.4 +/- 5.4 nmol/l), and in periphery (46.8 +/- 5.3 vs. 27.1 +/- 5.3 nmol/l) compared to controls. Plasma ACTH concentrations, however, did not differ in fetuses of both treatment groups. Postnatal LH-RH challenge tests (1st and 28th day post partum) induced LH surges in female piglets (n=67) both of ACTH and saline treated sows, but did not differ between groups (1st day: 7.2 +/- 0.8 vs. 8.1 +/- 0.7 ng/ml; 28th day: 10.5 +/- 1.7 vs. 13.6 +/- 2.2 ng/ml). However, basal LH of piglets whose mothers were submitted to ACTH during 2nd TP was lower on 1st day (1.7 +/- 0.2 vs. 2.3 +/- 0.2 ng/ml, p<0.05) but not on 28th day (1.0 +/- 0.2 vs. 1.1 +/- 0.2 ng/ml). However in both groups, the basal LH was always higher on 1st as on 28th day (p<0.05). Thus, chronic intermittent ACTH administration is able to influence the release pattern of maternal reproductive hormones. However, these findings demonstrate that these effects are dependent on the stage of pregnancy. Furthermore, it was shown that maternal cortisol can cross the placenta during gestation and thus may affect maternal-fetal interactions and, as a result, reproductive function of offspring.     

Residual feed intake of purebred Angus steers: effects on meat quality and palatability

Relationships between residual feed intake (RFI) and other performance variables were determined using 54 purebred Angus steers. Individual feed intake and BW gain were recorded during a 70-d post-weaning period to calculate RFI. After the 70-d post-weaning test, steers were fed a finishing ration to a similar fat thickness (FT), transported to a commercial facility, and slaughtered. A subsample of carcasses (n = 32) was selected to examine the relationships among RFI, meat quality, and palatability. Steers were categorized into high (> 0.5 SD above the mean; n = 16), medium (mid; +/- 0.5 SD from the mean; n = 21), and low (< 0.5 SD below the mean; n = 17) RFI groups. No differences were detected in ADG, initial BW, and d 71 BW among the high, mid, and low RFI steers. Steers from the high RFI group had a greater DMI (P = 0.004) and feed conversion ratio (FCR; DMI:ADG; P = 0.002) compared with the low RFI steers. Residual feed intake was positively correlated with DMI (r = 0.54; P = 0.003) and FCR (r = 0.42; P = 0.002), but not with initial BW, d 71 BW, d 71 ultrasound FT, initial ultrasound LM area, d 71 ultrasound LM area, or ADG. The FCR was positively correlated with initial BW (r = 0.46; P = 0.0005), d 71 BW (r = 0.34; P = 0.01), and DMI (r = 0.40; P = 0.003) and was negatively correlated with ADG (r = -0.65; P = 0.001). There were no differences among RFI groups for HCW, LM area, FT, KPH, USDA yield grade, marbling score, or quality grade. Reflectance color b* scores of steaks from high RFI steers were greater (P = 0.02) than those from low RFI steers. There was no difference between high and low RFI groups for LM calpastatin activity. Warner-Bratzler shear force and sensory panel tenderness and flavor scores of steaks were similar across RFI groups. Steaks from high RFI steers had lower (P = 0.04) off-flavor scores than those from low RFI steers. Cook loss percentages were greater (P = 0.005) for steaks from low RFI steers than for those from mid RFI steers. These data support current views that RFI is independent of ADG, but is correlated with DMI and FCR. Importantly, the data also support the hypothesis that there is no relationship between RFI and beef quality in purebred Angus steers.     

Equal performance of TaqMan, MGB, molecular beacon, and SYBR green-based detection assays in detection and quantification of roundup ready soybean

We have tested and compared the performance of 12 different assays representing four different real-time polymerase chain reaction (PCR) chemistries in the context of genetically modified organism detection. Several different molecular beacon, SYBR Green, TaqMan, and MGB assays were designed for the event specific detection and quantification of the 3' integration junction of GTS 40-3-2 (Roundup Ready) soybean. Sensitivity as well as robustness in the presence of background DNA were tested. None of the PCR-based approaches appeared to be significantly better than any of the other, but the molecular beacon assays had the lowest efficiency and also seemed more sensitive to changes in experimental setup.