In vitro effect of levamisole on the cell viability,phagocytosis and respiratory burst of Barbel chub (Squaliobarbus curriculus) macrophages

The present study was to determine in vitro effect of levamisole on the immune functions of Barbel chub (Squaliobarbus curriculus), head–kidney‐derived (HKM), spleen‐derived (SM) and peripheral blood monocyte‐derived macrophage (PBM). Macrophages were incubated with levamisole 10³, 10¹, 10⁻¹ and 10⁻³ ng mL⁻¹ to assay the cell viability, respiratory burst and phagocytosis. The results showed that macrophages treated with levamisole 10⁻³ ng mL⁻¹ gave a maximum respiratory burst response, whereas levamisole 10³ ng mL⁻¹ had no effect. Phagocytosis activity of the macrophages treated with levamisole enhanced significantly when compared to control, maximum response being at 10⁻³ ng mL⁻¹. While using the methylthiazoletetrazolium method to measure the cell activity for 12, 24, 36, 48, 60 h, there was no significant role on proliferation and the cell viability began to decline after 24 h. In conclusion, levamisole is a potent enhancer of Barbel chub macrophage activity with low concentration.     

Influence of the root endophyte Piriformospora indica on the plant water relations,gas exchange and growth of Chenopodium quinoa at limited water availability

This study aimed to evaluate the ability of Piriformospora indica to colonize the root of Chenopodium quinoa and to verify whether this endosymbiont can improve the growth, performance and drought resistance of this species. The study delivered, for the first time, evidence for successful colonization of P. indica in quinoa. Hence, pot experiment was conducted in the greenhouse, where inoculated and non‐inoculated plants were subjected to ample (40%–50% WHC) and deficit (15%–20%WHC) irrigation treatments. Drought adversely influenced the plant growth, leading to decline the total plant biomass by 74%. This was linked to an impaired photosynthetic activity (caused by lower g_s and C_i/C_a ratio; stomatal limitation of photosynthesis) and a higher risk of ROS production (enhanced ETR/A_gross ratio). P. indica colonization improved quinoa plant growth, with total biomass increased by 8% (controls) and 76% (drought‐stressed plants), confirming the growth‐promoting activity of P. indica. Fungal colonization seems to diminish drought‐induced growth hindrance, likely, through an improved water balance, reflected by the higher leaf ψ_w and g_s. Additionally, stomatal limitation of photosynthesis was alleviated (indicated by enhanced C_i/C_a ratio and A_net), so that the threat of oxidative stress was minimized (decreased ETR/A_gross). These results infer that symbiosis with P. indica could negate some of the detrimental effects of drought on quinoa growth, a highly desired feature, in particular at low water availability.     

Genetic diversity and relatedness estimates for captive barramundi (Lates calcarifer,Bloch) broodstock informs efforts to form a base population for selective breeding

Aquaculture of barramundi or Asian seabass (Lates calcarifer) is growing in both Australia and Southeast Asia and there is substantial interest to improve production efficiency through selective breeding. The establishment of a large and genetically diverse base population is a prerequisite for a sustainable and long‐term productive breeding program. Before selective breeding programs can begin for Australian barramundi it is important to assess the overall genetic diversity of current captive broodstock populations. To address this question, 407 captive barramundi broodstock from eight separate Australian broodstock populations were genotyped using 16 polymorphic microsatellite DNA markers. A Bayesian STRUCTURE analysis indicated that captive Australian broodstock are broadly divided into two genetic stocks. Multivariate analysis between broodstock individuals and pairwise F_ST between broodstock populations also supported the existence of two stocks. Comparisons with data obtained from natural stocks suggested that hatchery individuals were either sourced from the two stocks or represented an admixture between them. Genetic diversity was low within each broodstock population (allelic richness ranged from 2.67 to 3.42 and heterozygosity ranged from 0.453 to 0.537) and relatedness estimates within hatcheries were generally low (average r was equal to 0.141). We recommend sourcing captive individuals according to high levels of neutral genetic diversity and low levels of relatedness for the establishment of a base population. We also make recommendations about including genetically diverse wild individuals.     

Osteological development and anomalies in larval stage of hatchery‐reared yellow catfish Pelteobagrus fulvidraco

Comprehensive knowledge of osteological development of fish not only provides means for understanding its functional development, but also allows early detection of skeletal anomalies. The present study was conducted to determine osteological development and occurrence of anomalies from the first to the 40th day after hatching (DAH) for yellow catfish Pelteobagrus fulvidraco, a commercially important species in China. Vertebral ontogeny started with formation of anterior neural arches at 3 DAH, and completed at 6 DAH. Vertebral centra started to develop at 4 DAH and ossification in all centra was visible at 15 DAH. Caudal fin appeared at 2 DAH and ossification was visible at 26 DAH. The onset of dorsal and anal fins appeared at 4 DAH and their ossifications were visible at 20 DAH. Pectoral fins were present before first feeding and formed entirely at 9 DAH, and their ossifications were visible at 21 DAH. Pelvic fins appeared at 9 DAH, and formed completely at 21 DAH. The ossification of pelvic fins was not finished until the end of the experiment (40 DAH). 24 types of skeletal anomalies were observed. About 20% of individuals showed at least one anomaly. Haemal vertebrae anomalies occurred at the highest frequency, followed by pre‐haemal, caudal vertebrae and anal fin anomalies, and caudal fin had the lowest anomalies frequency. For the first time, our study determined osteological development and anomalies incidence in larval yellow catfish, which help further investigations into rearing conditions leading to appearance of these anomalies to prevent their incidence.     

Grassland responses to grazing disturbance: plant diversity changes with grazing intensity in a desert steppe

This study quantifies the impact of four different grazing regimes (heavy, moderate, light and ungrazed) on the vegetation dynamics of rangeland ecosystems along the southern boundary area of the Mu Us Desert, China. As the grazing intensities decreased, the soil quality, canopy cover, height, density, above‐ and below‐ground biomass, litter, root/shoot ratio and native plant (Aneurolepidium dasystachys) and grass abundances significantly increased; the above‐ground biomass of grasses increased, but the above‐ground biomass of forbs decreased. Ungrazed grassland has significantly improved from grasslands experiencing three other levels of grazing pressure, especially in the grassland biomass. Species richness increased as the grazing intensity decreased in the grazing grasslands, but peak species richness appeared under moderate and light grazing against lower productivity. Grazing exclusion causes desirable transitions in plant communities of desert steppe rangelands. Therefore, appropriate and efficient grazing exclusion is an available way to counteract local grassland degradation and promote rangeland sustainability.     

Prevalence and Prognostic Importance of Pulmonary Hypertension in Dogs with Myxomatous Mitral Valve Disease

Background

Pulmonary hypertension (PH) is common in dogs with myxomatous mitral valve disease (MMVD) but its effect on clinical outcome has not been investigated.

Hypothesis/objectives

The presence of PH worsens the outcome in dogs with MMVD. To compare survival times of dogs with MMVD and PH to those without PH.

Animals

Two hundred and twelve client‐owned dogs.

Methods

Case review study. Medical records of dogs diagnosed with ACVIM stage B2 and C MMVD between January 2010 and December 2011 were retrospectively reviewed. Long‐term outcome was determined by telephone interview or from the medical record. End of the observation period was March 2013. PH was identified if tricuspid regurgitation peak velocity was >3 m/s.

Results

Two hundred and twelve were identified. Eighty‐three dogs (39%) had PH. PH was more commonly identified in stage C compared to B2 (P < .0001). One hundred and five (49.5%) dogs died during the observation period. Median survival time for the entire study population was 567 days (95% CI 512–743). Stage C (P = .003), the presence of PH (P = .009), left atrial to aortic root ratio (LA/Ao) >1.7 (P = .0002), normalized left‐ventricular end‐diastolic diameter (LVEDn) >1.73 (P = .048), and tricuspid regurgitation pressure gradient (TRPG) >55 mmHg (P = .009) were associated with worse outcomes in the univariate analyses. The presence of TRPG >55 mmHg (HR 1.8 95% CI 1–2.9; P = .05) and LA/Ao > 1.7 (HR 2 95% CI 1.2–3.4; P = .01) remained significant predictors of worse outcome in the multivariate analysis.

Conclusions and Clinical Importance

In dogs with MMVD, moderate to severe PH worsens outcome.     

Seasonality in Saint Croix male lamb reproductive development in northern Mexico

The aim of this study was to determine the influence of the season of birth on the body weight, testicular size, testosterone concentrations, semen output and sexual behaviour in Saint Croix male lambs. Thirty‐three lambs were born in spring (n = 10), summer (Sum; n = 12) or autumn (n = 11). Body weight and the scrotal circumference were weekly recorded; semen was also weekly collected by electroejaculation; and sexual behaviour towards oestrous ewes was weekly evaluated. Data were recorded from 15 to 33 weeks of age. The reproductive development of Saint Croix male lambs differed according to the period in which they were born. More lambs born in spring than in summer and autumn achieved puberty during this study and were also more precocious in semen production and displayed sexual behaviour earlier. Lambs born in summer delayed their semen production; however, season‐related negative effects were less pronounced at the end of the study than in autumn born lambs born. In conclusion, despite the apparently low seasonality of the breed, Saint Croix male lambs showed in this study a seasonal pattern in their reproductive development at least until they achieve the puberty.     

Marker‐assisted parentage analysis reveals high individual selfing rates in tetraploid red clover genotypes selected for seed yield

Seed yield is a major breeding target in tetraploid red clover. We investigated if marker‐assisted parentage analysis can identify progeny plants with two high seed‐yielding parents in tetraploid red clover and if this technique is more advantageous than traditional half‐sib selection. Parentage analysis was successfully performed on the progeny from the 10% highest seed‐yielding genotypes from a second‐cycle family selection trial: 16.0% of progeny were identified with a high seed‐yielding father. However, progeny plants with two high seed‐yielding parents did not produce more seeds than traditionally selected progeny (27.3 g vs. 30.7 g/plant, respectively). The 10% highest seed‐yielding genotypes displayed on average 2% self‐fertilization. Four genotypes were self‐fertile with individual selfing rates up to 20%. Our results discourage the use of marker‐assisted parentage analysis to improve seed yield in tetraploid red clover when the material has been preselected for seed yield. Breeders should be aware that intensive selection for seed yield in tetraploid red clover may inadvertently lead to selection for increased self‐fertility, which may increase inbreeding in the long term.