Validation of indicators used to assess unconsciousness in veal calves at slaughter

European legislation states that after stunning regular checks should be performed to guarantee animals are unconscious between the end of the stunning process and death. When animals are killed without prior stunning these checks should be performed before the animal is released from restraint. The validity of certain indicators used to assess unconsciousness under different stunning and slaughter conditions is under debate. The aim of this study was to validate the absence of threat-, withdrawal-, corneal- and eyelid reflex as indicators to assess unconsciousness in calves subjected to different stunning and slaughter methods. Calves (201±22 kg) were randomly assigned to one of the following four treatments: (1) Captive bolt stunning followed by neck cut in an inverted position (n=25); (2) Non-stunned slaughter in an upright position (n=7); (3) Non-stunned slaughter in an inverted position (180° rotation) (n=25); (4) Non-stunned slaughter in an upright position followed by captive bolt stunning 40 s after the neck cut (n=25). Each calf was equipped with non-invasive electroencephalogram (EEG) electrodes before the slaughter procedure. All reflexes were verified once before the slaughter procedure. At the beginning of the procedure (T=0 s) calves were stunned (treatment 1) or neck cut in an upright position (treatment 2, 4) or inverted position (treatment 3). Calves of treatment 4 were captive bolt stunned 34±8 s after the neck cut. Reflexes were assessed every 20 s from T=15 s for all treatments until all reflex tests resulted in a negative response three times in a row and a flat line EEG was observed. In addition, reflexes were assessed 5 s after captive bolt stunning in calves of treatments 1 and 4. Visual assessment of changes in the amplitude and frequency of EEG traces was used to determine loss of consciousness. Timing of loss of consciousness was related to timing of loss of reflexes. After captive bolt stunning, absence of threat-, withdrawal-, corneal- and eyelid reflex indicated unconsciousness as determined by EEG recordings. After non-stunned slaughter, both threat- and withdrawal reflex were on average lost before calves were unconscious based on EEG recordings. The eyelid- and corneal reflex were on average lost after calves had lost consciousness based on EEG recordings and appeared to be distinctly conservative indicators of unconsciousness in non-stunned slaughtered calves since they were observed until 76±50 and 85±45 s (mean±SD), respectively, after EEG-based loss of consciousness.     

Review: Potential alternatives to high-concentration carbon dioxide stunning of pigs at slaughter

Using carbon dioxide (CO₂) for stunning pigs at slaughter is common in Europe. The use of group stunning is a major advantage with CO₂, which is done without restraining the pigs and with minimized human contact. However, high concentrations of CO₂ have been known for decades to cause pain, fear and distress in pigs before loss of consciousness, and the stunning method is clearly associated with animal welfare concerns. This study reviewed the scientific literature to find recent developments or evaluations of alternative methods that could lead to the replacement of CO₂ for stunning pigs at slaughter. Potential alternative methods found in the literature were described and then assessed to identify specific research and development needs for their further development. Only 15 empirical studies were found in the search of peer-reviewed literature since 2004, which is less than one per year. Furthermore, half of the studies focused on evaluating methods to improve high-concentration CO₂ stunning rather than an alternative to CO₂. Since no clear alternative has emerged, nor a method to improve CO₂ stunning, there is obviously a strong need to focus research and development to find solutions for improving animal welfare when stunning pigs at slaughter.     

Use of a Marker Organism To Model the Spread of Central Nervous System Tissue in Cattle and the Abattoir Environment during Commercial Stunning and Carcass Dressing

Due to concerns about a link between variant Creutzfeldt-Jakob disease in humans and similar prion protein-induced disease in cattle, i.e., bovine spongiform encephalopathy (BSE), strict controls are in place to exclude BSE-positive animals and/or specified risk materials including bovine central nervous system (CNS) tissue from the human food chain. However, current slaughter practice, using captive bolt guns, may induce disruption of brain tissues and mobilize CNS tissues into the bovine circulatory system, leading to the dispersion of CNS tissues (including prion proteins) throughout the derived carcass. This project used a marker (antibiotic-resistant) strain of Pseudomonas fluorescens to model the effects of commercial captive bolt stunning procedures on the movement of mobilized CNS material within slaughtered animals and the abattoir environment. The marker organism, introduced by injection through the bolt entry aperture or directly using a cartridge-fired captive bolt, was detected in the slaughter environment immediately after stunning and in the abattoir environment at each subsequent stage of the slaughter-dressing process. The marker organism was also detected on the hands of operatives; on slaughter equipment; and in samples of blood, organs, and musculature of inoculated animals. There were no significant differences between the results obtained by the two inoculation methods (P < 0.05). This study demonstrates that material present in, or introduced into, the CNS of cattle during commercial captive bolt stunning may become widely dispersed across the many animate and inanimate elements of the slaughter-dressing environment and within derived carcasses including meat entering the human food chain.     

Use of a marker organism to model the spread of central nervous system tissue in cattle and the abattoir environment during commercial stunning and carcass dressing

Due to concerns about a link between variant Creutzfeldt-Jakob disease in humans and similar prion protein-induced disease in cattle, i.e., bovine spongiform encephalopathy (BSE), strict controls are in place to exclude BSE-positive animals and/or specified risk materials including bovine central nervous system (CNS) tissue from the human food chain. However, current slaughter practice, using captive bolt guns, may induce disruption of brain tissues and mobilize CNS tissues into the bovine circulatory system, leading to the dispersion of CNS tissues (including prion proteins) throughout the derived carcass. This project used a marker (antibiotic-resistant) strain of Pseudomonas fluorescens to model the effects of commercial captive bolt stunning procedures on the movement of mobilized CNS material within slaughtered animals and the abattoir environment. The marker organism, introduced by injection through the bolt entry aperture or directly using a cartridge-fired captive bolt, was detected in the slaughter environment immediately after stunning and in the abattoir environment at each subsequent stage of the slaughter-dressing process. The marker organism was also detected on the hands of operatives; on slaughter equipment; and in samples of blood, organs, and musculature of inoculated animals. There were no significant differences between the results obtained by the two inoculation methods (P < 0.05). This study demonstrates that material present in, or introduced into, the CNS of cattle during commercial captive bolt stunning may become widely dispersed across the many animate and inanimate elements of the slaughter-dressing environment and within derived carcasses including meat entering the human food chain.     

Pre-slaughter factors linked to variation in responses to carbon dioxide gas stunning in pig abattoirs

The stunning process is an important component of slaughter with implications for animal welfare due to the potential distress and pain in the case of a sub-effective or lengthy stun. This study examined the factors correlated with variation in responses to carbon dioxide (CO₂) stunning of pigs in five Australian commercial abattoirs. A total of 1 769 pigs (199–492 focal pigs per abattoir) were individually followed from lairage to post-stunning. A standardised observation protocol was used based on a literature review of the pre-slaughter factors that may influence the reaction to CO₂ stunning, such as animal background, lairage conditions, handling, stunning system and conditions. Pigs lost posture 22.5 ± 0.2 s after commencement of descent of the gondola into the CO₂ chamber. Latency to loss of posture was associated with farm of origin and time of day, which could be linked to various factors. Pigs that crawled or attempted to escape while in the gondola within the CO₂ chamber took longer to lose posture. Crawl and escape attempts differed between abattoirs (0.6–46.2% of the pigs observed) as well as mounting other pigs (1.0–24.3%). Greater amounts of forceful contacts during handling in the race were related to more mounting in the gondola, but to less pigs crawling or attempting to escape. Mounting in the gondola was more frequent for pigs from lairage pens of mixed sexes, followed by pens of entire males and finally pens of females. Males were also twice as likely to show crawl and escape attempts than females. Gasping in the gondola was relatively frequent (63.1–81.8%) and was associated with higher activity in the lairage pen and higher skin injuries. Convulsions (60.1–69.6%) were generally observed after loss of posture. The type of CO₂ system (group-wise vs single-file loading) had no significant effect on behaviour in the gondola. Nevertheless, pigs slaughtered in abattoirs with group-wise loading systems and automatic gates had lower cortisol concentrations post-stunning, which may be linked to minimal handling by stockpeople, other factors related to the systems, or differences in timing of when blood samples were taken. In conclusion, substantial variation in the reaction of pigs to CO₂ stunning was observed between and within abattoirs using a uniform protocol for data collection. This variation in outcomes between abattoirs and stunning systems and the relationships between handling and behavioural outcomes indicates that improvements can be made to reduce aversive responses to CO₂ stunning. In particular, avoiding mixing pigs of different sexes in lairage and aversive handling in the race may reduce aversive response to CO₂ stunning.     

Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality

The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N₂) and 30% carbon dioxide (CO₂; 70N30C), 80% N₂ and 20% CO₂ (80N20C) and 85% N₂ and 15% CO₂ (85N15C) on aversion, stunning effectiveness and carcass, as well as meat quality in pigs, and to compare them with the commercial stunning of 90% CO₂ (90C). A total of 68 female pigs were divided into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts, escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at 24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS® were used to analyse the parametric and binomial variables, respectively. The ‘gas mixture’ was always considered a fixed effect and the ‘live weight’ as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular excitation phase than pigs exposed to the other N₂ and CO₂ mixtures (P < 0.05). After stunning, no pig exposed to 90C showed corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N₂ and CO₂ mixtures showed corneal reflex and rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P < 0.01) than animals exposed to 90C. Electrical conductivity in the SM muscle was lower (P < 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in LT, it was lower (P < 0.05) in 90C pigs than in 85N15C. As the CO₂ concentration of the gas mixture was decreased, the prevalence of exudative pork increased. Twenty-five percent of animals exposed to N₂ and CO₂ mixtures (n = 68) had ecchymosis in their carcasses, whereas no animal stunned with 90C had ecchymosis. In conclusion, although N₂ and CO₂ stunning exhibit fewer signs of aversion than 90C, their induction time to unconsciousness is longer, and this may negatively affect meat and carcass quality.     

Carbon dioxide capture by planar (AlN)<Subscript>n</Subscript> clusters (<Emphasis Type="Italic">n</Emphasis>=3–5)

Searching for materials and technologies of efficient CO₂ capture is of the utmost importance to reduce the CO₂ impact on the environment. Therefore, the (AlN)_n clusters (n = 3–5) are researched using density functional theoretical calculations. The results of the optimization show that the most stable structures of (AlN)_n clusters all display planar configurations at B3LYP and G3B3 methods, which are consistent with the reported results. For these planar clusters, we further systematically studied their interactions with carbon dioxide molecules to understand their adsorption behavior at the B3LYP/6–311+G(d,p) level, including geometric optimization, binding energy, bond index, and electrostatic. We found that the planar structures of (AlN)_n (n = 3–5) can capture 3–5 CO₂ molecules. The result indicates that (AlN)_n (n = 3–5) clusters binding with CO₂ is an exothermic process (the capture of every CO₂ molecule on (AlN)_n clusters releases at least 30 kcal mol^-1 in relative free energy values). These analysis results are expected to further motivate the applications of clusters to be efficient CO₂ capture materials.     

Hot-water spraying is a sensitive test for signs of life before dressing and scalding in pig abattoirs with carbon dioxide (CO2) stunning

This study investigated the benefits of hot-water spraying (HWS) as a diagnostic test to verify the absence of signs of life (SOL) before scalding in pigs slaughtered with carbon dioxide (CO₂) stunning. A total of 37 108 finishing pigs from five German abattoirs (A to E) operating at 55 to 571 pigs per hour were assessed. Suspended pigs were sprayed onto the muzzle, head and front legs (143 to 258 s post sticking for 4 to 10 s, 57°C to 72°C). Any active movements during HWS were rated as positive test outcomes. In comparison, SOL were considered to be absent if a subsequent manual examination was negative and no active movements were observed following HWS. The incidence of pigs with activity during hot-water spraying (PWA) was restricted to two abattoirs (B: 0.25%; D: 0.02%; A, C, E: 0.00%). PWA showed movements of facial muscles (88%), mouth opening (78%), righting reflex (63%), isolated leg movements (35%) and vocalization (4%). The manual examination was positive in 71% of PWA (corneal/dazzle reflex: 67%/53%, nasal septum pinch: 33%), whereas all inactive pigs tested negative (P<0.001). The sensitivity for HWS as a test for SOL was calculated as 100%, dropping to 75% when only obvious and strong movements were taken into account. The specificity was >99.9% in either case. Any positive manual findings as well as any respiratory activity were instantly terminated using a penetrating captive bolt. Active movements triggered by the shot were shown to be an indicator for SOL (P<0.001). Video analyses revealed that spontaneous movements (SM) following sticking were present in 100% of PWA as opposed to 3.1% in pigs without such activity (controls). Results for different categories of SM in PWA v. controls were as follows: 100% v. 2.6% for mouth opening, 16.0% v. 0.1% for righting reflex and 22.0% v. 0.9% for isolated leg movements (all P<0.001). First mouth opening after sticking was observed later in PWA (28±24 v. 10±7 s), but mouth openings were observed for a longer period of time (141±44 v. 27±25 s) (both P<0.001). PWA with shorter mouth-opening intervals showed higher movement intensities during HWS and more positive manual findings (P<0.05). We conclude that HWS is a promising test for SOL. SM and sustained mouth opening in particular are indicators for compromised animal welfare and affected pigs should be shot by captive bolt.     

Ability of the Public to Recognize Dogs Considered to Be Dangerous under the Dangerous Dogs Act in the United Kingdom

Canine aggression came into the public eye in the United Kingdom in the late 1980s prompting enactment of the UK Dangerous Dogs Act , which prohibits four breeds or “types” of dogs. The act faced strong opposition surrounding correct identification of prohibited dogs. A questionnaire was distributed to the public via an online platform, especially targetting those who have worked with dogs. The questionnaire assessed respondents’ abilities to identify the four banned types of dogs from other breeds and their capability to identify Pit Bull Terrier types from other similar dog types. Identification of both banned breeds, F(1, 20) = 57.746, p < .001, and bull breeds, F(1, 20) = 9.293, p = .006, was significantly lower than identification of other breeds. Recognition of Pit Bull Terrier types from similar types of dogs was generally poor, although people in a dog-related profession, as opposed to those in other professions, could correctly distinguish more pit bull-type dogs (U = 46,164.0, n₁ = 187, n₂ = 575, p = .003). Findings suggest public understanding of dangerous dogs is poor, and it may impact societal perceptions of dogs more widely.     

Stunning fish with CO2 or electricity: contradictory results on behavioural and physiological stress responses

Studies that address fish welfare before slaughter have concluded that many of the traditional systems used to stun fish including CO₂ narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char (Salvelinus alpinus) stunned with CO₂ or electricity. Exposure to water saturated with CO₂ triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fish exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fish to recover from electrical stunning, whereas fish stunned with CO₂ did not recover. Despite this, the electrically stunned fish had more than double the plasma levels of cortisol compared with fish stunned with CO₂. This result is surprising considering that the behavioural reactions were much more pronounced following CO₂ exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.     

Molecular dynamics simulation study of probe diffusion in liquid n-alkanes

We performed molecular dynamics simulations for the probe diffusion and friction dynamics of Lennard-Jones (LJ) particles modelled for methyl yellow (MY) in liquid n-alkanes of C₁₂–C₂₀₀ at temperatures of 318, 418, 518 and 618 K. Two LJ particles are chosen: MY1 with a mass of 114 g/mol, LJ parameters of σ = 4.0 Å and ? = 0.4 kJ/mol, and MY2 with a mass of 225 g/mol, σ = 6.0 Å and ? = 0.6 kJ/mol. We observed a clear transition in the power law dependence of MY2 diffusion on the molecular weight of n-alkanes at lower temperatures of 318 and 418 K. The sharp transitions occur near n-dotriacontane (C₃₂). However, no such transition is found for MY1 at all the temperatures and for MY2 at higher temperatures of 518 and 618 K. We also calculated the friction constants of both MY probe molecules in liquid n-alkanes. For the larger probe molecule (MY2), at lower temperatures, a large deviation of slope from the linear dependence of the friction of MY2 on the chain length of n-alkane is observed, which indicates a large reduction of friction in longer chains when compared with the shorter chains, enhancing the diffusion of the probe molecules (MY2).     

Karyotype analysis of the southernmost South American species of Stemodia (Scrophulariaceae)

Abstract

The aim of the present study was to examine the somatic chromosomes of seven species of Stemodia (Scrophulariaceae). The karyotypes of Stemodia ericifolia (2n = 22 = 20m + 2 sm), S. hassleriana (2n = 22 = 20m + 2sm), S. hyptoides (2n = 22 = 20m + 2sm), S. hyptoides (2n = 44 = 40m + 4sm), S. lobelioides (2n = 44 = 40m + 4sm) and S. stricta (2n = 22 = 20m + 2sm) were analyzed for the first time. All the species studied showed a predominance of metacentric chromosomes and a lower proportion of submetacentric pairs. The chromosomes in all the species were found to be small with a mean chromosome length of 1.42 μm, varying from 0.77 μm in S. hyptoides (2n = 66) to 2.10 μm in S. lanceolata. The differences in the asymmetry of the karyotypes were small, for which it is possible to assume that the great diversification of the genus has been accompanied by very small changes in the structure of the chromosomes.     

Comparative Genetic Diversity of Wild and Captive Populations of the Bare-Faced Curassow (Crax fasciolata) Based on Cross-Species Microsatellite Markers: Implications for Conservation and Management

The bare-faced curassow (Crax fasciolata) is a large Neotropical bird that suffers anthropogenic pressure across much of its range. A captive population is maintained for conservation management, although there has been no genetic screening of stocks. Based on the six microsatellite markers developed for Crax globulosa, the genetic variability of C. fasciolata and possible differences between a wild and a captive population were investigated. Only three loci were polymorphic, with a total of 27 alleles. More than half of these alleles were private to the wild (n = 8) or captive (n = 7) populations. Significant deviations from Hardy–Weinberg equilibrium were restricted to the captive population. Despite the number of private alleles, genetic drift has probably promoted differentiation between populations. Our results indicate that wild C. fasciolata populations are genetically impoverished and structured, but species-specific microsatellite markers will be necessary for a more reliable assessment of the species’ genetic diversity.     

Effect of age at the beginning of the free-range fattening period on growth and carcass and fat quality in Iberian pigs

Abstract

This experiment was carried out to study the influence of age at the beginning of the free-range fattening period (traditional pigs, TP, age 12 months vs. young pigs, YP, age 8 months) on the performance of Iberian pigs. During 152 days prior to the fattening period, TP and YP pigs received 1.7 and 2.6 kg feed per day, respectively. During fattening, TP pigs had a higher average daily gain (p < 0.05) than YP pigs. The proportions of PUFA and n-3 fatty acids of the outer and inner layers of subcutaneous backfat were higher in TP than in YP pigs (p < 0.05), while the proportions of C16:0 and SFA in the inner layer of subcutaneous backfat were greater in YP than in TP pigs (p < 0.05). The ratio of n-6/n-3 in subcutaneous backfat was lower in TP than in YP pigs (p < 0.05). The percentage of intramuscular fat in longissimus dorsi muscle was higher in TP than in YP pigs (p < 0.05). The relationship between the percentage of intramuscular fat in longissimus dorsi muscle and average daily gain during the free-range fattening period adjusted to a quadratic function (p < 0.05). The concentration of α- and γ-tocopherol in subcutaneous backfat at slaughter was significantly higher in TP than in YP pigs (p < 0.05). It is concluded that Iberian pigs that have 8 months of age at the beginning of free-range feeding have adequate commercial quality.     

Lipid metabolism in pigs fed supplemental conjugated linoleic acid and/or dietary arginine

We proposed that the combination of conjugated linoleic acid (CLA) and arginine would decrease adiposity by depressing lipid synthesis in liver and adipose tissues of growing pigs. Pigs were allotted to treatments in a 2 × 2 factorial design with two lipids (CLA or canola oil) and two amino acids [l-arginine or l-alanine (isonitrogenous control)]; supplements were provided from 80 to 110 kg body weight (approximately 4 weeks). Treatment groups (n = 4) were: control (2.05% l-alanine plus 1% canola oil); CLA (2.05% l-alanine plus 1% CLA); arginine (1.0% l-arginine plus 1.0% canola oil); arginine plus CLA (1.0% arginine plus 1.0% CLA). Arginine increased backfat thickness (P = 0.07) in the absence or presence of CLA, and arginine supplementation increased subcutaneous and retroperitoneal adipocyte volume, especially in combination with dietary CLA (interaction P = 0.001). Arginine increased palmitate incorporation into total lipids by over 60% in liver (P = 0.07). Dietary CLA increased palmitate incorporation into lipids in longissimus muscle by over 100% (P = 0.01), and CLA increased longissimus muscle lipid by nearly 20%. CLA increased glucose oxidation to CO₂ by over 80% in retroperitoneal and subcutaneous adipose tissues (P = 0.04), and doubled palmitate oxidation to CO₂ in intestinal duodenal mucosal cells (P = 0.07). Arginine supplementation decreased muscle pH at 45 min postmortem (P = 0.001), indicating elevated early postmortem glycolysis, and CLA and arginine independently increased PGC-1α gene expression in longissimus muscle. CLA but not arginine depressed mTOR gene expression in intestinal duodenal mucosal cells. CLA decreased serum insulin by 50% (P = 0.02) but increased serum triacylglycerols by over 40%. CLA supplementation increased (P ≤ 0.01) total saturated fatty acids in liver and adipose tissue. In conclusion, neither CLA nor arginine depressed tissue lipid synthesis in growing/finishing pigs, and in fact dietary CLA promoted elevated intramuscular lipid and arginine increased carcass adiposity.     

Prediction of digestible and metabolisable energy in soybean meals produced from soybeans of different origins fed to growing pigs

The objective of this experiment was to determine the digestible energy (DE) and metabolisable energy (ME) in 22 sources of soybean meal (SBM) produced from soybeans from different countries and subsequently to establish equations for predicting the DE and ME in SBM based on their chemical composition. The 22 sources of SBM were all processed in Chinese crushing plants, but the soybeans used originated from China (n = 6), the US (n = 6), Brazil (n = 7) or Argentina (n = 3). The basal diet was a corn-based diet and 22 additional diets were formulated by mixing corn and 24.3% of each source of SBM. The average DE and ME in SBM from China, the US, Brazil and Argentina were 15.73, 15.93, 15.64 and 15.90 MJ/kg and 15.10, 15.31, 14.97 and 15.42 MJ/kg, respectively, and no differences among countries were observed. From a stepwise regression analysis, a series of DE and ME prediction equations were generated. The best-fit equations for SBM were DE = 38.44–0.43 crude fibre ?0.98 gross energy +0.11 acid detergent fibre (R² = 0.67, p < 0.01) and ME = 2.74 + 0.97 DE ?0.06 crude protein (R² = 0.79, p < 0.01). In conclusion, there were no differences in the DE and ME of SBM among the different soybean sources used in this experiment. The DE and ME of SBM of different origin can be predicted based on their chemical composition when fed to growing pigs.     

Influenza della temperatura sullo sviluppo della “Dicranophora fulva„ Schröter

Abstract

Karyotype features and microsporogenesis of Tripogandra diuretica (Mart.) Handlos and Tripogandra glandulosa (Seub.) Rohw. from 15 NE Argentina accessions are analysed via classical cytogenetics, CMA/DA/DAPI and Ag-NOR. The karyotype of T. glandulosa (2n = 2x = 16; 2m + 6sm + 8st) is bimodal (A ₂ = 0.37; R = 2.65) and asymmetrical (A ₁ = 0.63; i = 26.06; r > 2 = 0.88) (3B-Stebbins) with a genome size of 33.28 μm; two pairs are satellited, CMA+ and NOR-actives. Another four CMA+ loci and DAPI+ universal centromeric heterochromatin occur. Microsporogenesis is normal (pollen viability short stamens = 97.8%; large = 96.7%), meiotic behaviour is regular and chromosomes pair as 8II. The karyotype of T. diuretica (2n = 8x = 64; 8m + 24sm + 32st) is bimodal (A ₂ = 0.27; R = 2.54) and asymmetrical (A ₁ = 0.60; i = 27.32; r > 2 = 0.88) (3B-Stebbins); additionally, two pairs are satellited. Microsporogenesis is normal (short stamens = 77.8%; large = 68.5%), except for micronuclei and low pollen viability in some accessions. Meiotic behaviour is regular with 32II, acting as a cytological diploid, however the arrangement of the haploid karyotype suggests that T. diuretica, which also exhibits a reduction of the genome size (18.58 μm), constitutes an auto-octoploid taxa. Additionally, both species share cytological features common to karyotype orthoselection.     

Chromosome investigations in annual Medicago species (Fabaceae) with emphasis on the origin of the polyploid Medicago rugosa and M. scutellata

Chromosome number variations play an important role in the genus Medicago. In addition to polyploidy there are cases of dysploidy as evidenced by two basic numbers, x = 8 and x = 7, the latter limited to five annual species having 2n = 14. Annuals are diploid with the exception of Medicago scutellata and Medicago rugosa which have 2n = 30 and are considered the result of crosses between the 2n = 16 and 2n = 14 species. However, this hypothesis has never been tested. This study was carried out to investigate the 2n = 14 and 2n = 30 karyotypes and verify the allopolyploid origin of M. scutellata and M. rugosa. Fluorescence in situ hybridization (FISH) of rDNA probes and genomic in situ hybridization (GISH) were performed. FISH showed that all five diploids with 2n = 14 have one pair of 45S and one pair of 5S rDNA sites. M. scutellata displayed four sites of 45S and four sites of 5S rDNA, while in M. rugosa only one pair of each of these sites was found. GISH did not produce signals useful to identify the presumed progenitors with 14 chromosomes. This result suggests alternative evolutionary pathways, such as the formation of tetraploids (2n = 32) and subsequent dysploidy events leading to the chromosome number reduction.     

Serological survey suggests circulation of coronavirus on wild Suina from Argentina, 2014–2017

Swine coronaviruses affecting pigs have been studied sporadically in wildlife. In Argentina, epidemiological surveillance of TGEV/PRCV is conducted only in domestic pigs. The aim was to assess the prevalence of TGEV/PRCV in wild Suina. Antibodies against these diseases in wild boar and captive collared peccary were surveyed by ELISA. Antibodies against TGEV were found in three collared peccaries (n?=?87). No TGEV/PRCV antibodies were detected in wild boar (n?=?160). Preventive measures should be conducted in contact nodes where the transmission of agents may increase. Epidemiological surveillance in wildlife populations and in captive animals before their reintroduction should be attempted.

     

Comparison of pulmonary vascular response to endogenous nitric oxide inhibition in sheep and pigs living at 2,300 m

To compare the role of nitric oxide in an adaptive process to chronic hypoxia, we examined the effects of endogenous nitric oxide synthase inhibition on pulmonary vascular tone in conscious sheep and pigs living at high altitude. Unanesthetized male sheep (n=6) and pigs (n=5), born and residing in the highlands of Qinghai Province, China (2,300–3,000 m a.s.l.) were studied at that altitude. Pulmonary artery pressure (P_pa), pulmonary artery wedge pressure (P_cwp), and cardiac output (CO) were measured. Pulmonary vascular resistance (PVR) was calculated as (P_pa—P_cwp)/CO. Using a climatic chamber, hemodynamic measurements during exposures to atmospheric pressures corresponding to altitudes of 0, 2,300, and 4,500 m a.s.l. were performed with and without NO inhibition, using N^w-nitro-l-argine (NLA; 20 mg kg^–1), a potent stereospecific competitive inhibitor of nitric oxide synthase. P_pa and PVR at baseline (2,300 m) and during hypoxic exposure (4,500 m) were significantly higher in pigs than in sheep. After NLA administration, P_pa increased and CO decreased in both animals, resulting in significantly increased PVR at baseline and during hypoxic exposure. However, there were no significant differences in the percent increase in basal or hypoxic PVR after NLA administration between sheep and pigs. We conclude that augmented endogenous NO production could contribute to the regulation of pulmonary vascular tone at high altitude in sheep and pigs. However, it is unlikely that NO is responsible for the different pulmonary vascular tones between sheep and pigs at basal condition at moderately high altitude.Communicated by G. Heldmaier