Patterns of SSR variation in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) seeds under ex situ genebank storage and accelerated ageing

Maintaining seed viability and germplasm integrity is a challenging task in conservation of plant genetic resources, as seeds under storage will lose viability and genetic changes will occur. Attempt was made to analyze the patterns of genetic changes in wheat germplasm under ex situ genebank storage and accelerated ageing treatments. A set of 16 naturally aged wheat accessions under ex situ genebank storage since 1994 were sampled. Four recently regenerated wheat accessions were selected, four random seed samples were chosen from each accession, and three of them were exposed to three different accelerated ageing treatments. These 32 seed samples in two germplasm sets displayed a range of germination rates from 4 to 98 %. Thirty-seven microsatellite markers representing 21 wheat chromosomes were applied to screen 12 seeds of each sample and 449 SSR alleles were scored. Large SSR variation was found in each germplasm set. There was 73.1 % of the total SSR variation present among the naturally aged samples and 78.2 % present among the accelerated ageing samples. Several analyses for genetic association consistently revealed no clear genetic separations among samples of high or low germination rates in both germplasm sets. Samples under different accelerated ageing treatments did not show much genetic differentiations from the original sample of each accession. Mantel tests revealed non-significant associations between SSR variability and sample germination rates for both germplasm sets. These findings are useful for understanding seed deterioration under different ageing conditions and suggest that genome-wide SSR variability may not provide sensitive markers for the monitoring of wheat seed viability.     

A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover

Supplementing conjugated linoleic acid ( CLA ) is supposed to spare glucose due to the milk fat‐depressing effect of the trans ‐10, cis ‐12 CLA isomer, and allows repartitioning nutrients despite an energy deficiency in early lactation. However, there is still a lack of knowledge in terms of the dynamic pattern of the glucose turnover in transition dairy cows. We hypothesized that dairy cows supplemented with CLA have an altered rate of glucose turnover and insulin sensitivity during early lactation. We conducted three consecutive hyperglycaemic clamps (HGC ) in weeks ?2, +2 and +4 relative to parturition in Holstein cows supplemented daily either with 70 g of lipid‐encapsulated CLA (6.8 g trans ‐10, cis ‐12 and 6.6 g of the cis ‐9, trans ‐11 CLA isomer; CLA ; n  = 11) or with 56 g of control fat ( CON ; n  = 11). From week ?3 up to week +4 relative to parturition, milk yield and dry matter intake (DMI ) were recorded daily, while body weight (BW ) and milk composition were obtained once weekly. Blood samples were taken once weekly and every 30 min during the HGC . Plasma was analysed for concentrations of glucose, fatty acids (FFA ), beta‐hydroxybutyrate (BHB ), insulin, triglycerides and cholesterol. The CLA supplementation did not affect performance and metabolic parameters except for BHB and cholesterol. Furthermore, insulin concentrations and insulin sensitivity were affected by treatment. During the HGC in early lactation, insulin response was lower and decrease in FFA and BHB greater compared with the HGC in week ?2 although glucose target concentration achieved during the steady‐state period was similar for all three HGC . Our findings in terms of insulin and cholesterol suggest that body reserves are preserved through CLA feeding without restraining animal's performance. Furthermore, CLA effects on cholesterol and triglyceride concentrations indicated beneficial effects on hepatic lipid export contributing to an improved efficiency of prevailing metabolites in circulation.     

Distribution and Diversity of Salmonella Strains in Shipments of Hatchling Poultry,United States, 2013

Multistate outbreaks of salmonellosis associated with live poultry contact have been occurring with increasing frequency. In 2013, multistate outbreaks of salmonellosis were traced back to exposure to live poultry, some of which were purchased at a national chain of farm stores (Farm store chain Y). This study was conducted at 36 stores of Farm store chain Y and was concurrent with the timing of exposure for the human outbreaks of salmonellosis in 2013. We used environmental swabs of arriving shipment boxes of hatchling poultry and shipment tracking information to examine the distribution, diversity and anti‐microbial resistance of non‐typhoidal Salmonella (NTS) across farm stores and hatcheries. Isolates recovered from shipment boxes underwent serotyping, anti‐microbial resistance (AMR) testing and pulsed‐field gel electrophoresis (PFGE). Postal service tracking codes from the shipment boxes were used to determine the hatchery of origin. The PFGE patterns were compared with the PFGE patterns of NTS causing outbreaks of salmonellosis in 2013. A total of 219 hatchling boxes from 36 stores in 13 states were swabbed between 15 March 2013 and 18 April 2013. NTS were recovered from 59 (27%) of 219 hatchling boxes. Recovery was not significantly associated with species of hatchlings, number of birds in the shipment box, or the presence of dead, injured or sick birds. Four of the 23 PFGE patterns and 23 of 50 isolates were indistinguishable from strains causing human outbreaks in 2013. For serotypes associated with human illnesses, PFGE patterns most frequently recovered from shipment boxes were also more frequent causes of human illness. Boxes positive for the same PFGE pattern most frequently originated from the same mail‐order hatchery. Only one of 59 isolates was resistant to anti‐microbials used to treat Salmonella infections in people. This study provides critical information to address recurrent human outbreaks of salmonellosis associated with mail‐order hatchling poultry.     

The use of ultrasonography in the reproductive evaluation of boars

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty‐six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.     

The effect of fertility control on the transmission of bovine tuberculosis in wild brushtail possums

AIM: To determine the effect of fertility control on the rate of transmission of bovine tuberculosis (Tb), caused by Mycobacterium bovis, in brushtail possums (Trichosurus vulpecula).

METHODS: At two study sites with a history of Tb infection in the resident possum population, a sample of adult male and female possums (n=50), determined by palpation to be Tb-free, was surgically sterilised by gonadectomy. A sample of untreated Tb-free male and female possums (n=54) served as controls. Each study site was trapped every 2 months over a 3-year period, and the Tb status of the individuals in the trial assessed. At the conclusion of the trial, all remaining experimental individuals were killed, necropsied and examined for characteristic lesions typical of Tb. The rate of transmission of Tb infection was estimated using the incidence of tuberculous cases in the experimental animals and comparing it between sites, sex and sterilisation treatment.

RESULTS: Sterilisation by gonadectomy resulted in a reduction in the rate of transmission of Tb in male possums by 53%, but a corresponding increase in sterilised females for reasons that are still unclear. However, this interaction was statistically weak (p=0.10). When the sexes were combined, there was no overall effect of sterilisation on the rate of transmission of Tb (p=0.43). Sterility treatment notwithstanding, there was a highly significant difference in the rate of transmission between the sexes (p=0.01), being almost one order of magnitude higher in untreated males compared with untreated females.

CONCLUSIONS: Although lacking strong statistical support, these results suggest that fertility control that targets endocrine control of fertility may provide some additional benefits for disease control over that achieved by reductions in population density, by reducing the rate of transmission of M. bovis in male possums. However, additional studies are needed to confirm the validity of these results. The large difference in the rate of transmission of M. bovis in untreated males compared with untreated females suggests that transmission of Tb among males may be an important driver of the dynamics of Tb infection in possums.