Tropical summer induces sperm DNA damage in boars which can be mitigated by antioxidant therapy

Despite pork being the most widely consumed meat in the world, summer infertility due to heat stress significantly reduces pig production and can potentially limit sustainable pork supply particularly in tropical regions. The boar's characteristic non-pendulous scrotum, inefficient capacity to sweat and the high susceptibility of boar sperm to temperature shock makes this species particularly vulnerable to heat stress. While traditionally considered a sow problem, recent studies demonstrate that DNA damage in sperm caused by heat stress can result in early embryo loss in mice. The aim of this study was to determine whether sperm DNA damage is higher during summer in boars and evaluate antioxidant supplementation to alleviate the problem

Antioxidant supplementation alleviates DNA damage in boar sperm induced by tropical heat stress

Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual loses. The boar’s reduced capacity to sweat, non-pendulous scrotum, and widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. While traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Data, expressed as mean ± SEM, were analysed by one-way repeated measures ANOVA with pairwise Bonferroni tests. Motility of sperm obtained from n = 5 Large White boars housed in the dry tropics of Townsville, North Queensland, Australia was characterized by Computer-Assisted Sperm Analysis but did not differ between summer, winter or spring (total motility: 71.3 ± 8.1 vs. 90.2 ± 4.2 vs. 70.8 ± 5.5% respectively, P > 0.05; progressive motility: 35.4 ± 7.0 vs. 46.6 ± 4.0 vs. 41.7 ± 2.8% respectively, P > 0.05). Sperm DNA integrity in 20,000 sperm/boar/season, evaluated using TUNEL and flow cytometry, revealed 16-fold more DNA damaged sperm in summer than winter, and nearly 9-fold more than spring (16.1 ± 4.8 vs. 1.0 ± 0.2 vs. 1.9 ± 0.5% respectively, P ≤ 0.05). However, boar feed supplemented with 100g/boar/day of proprietary custom-made antioxidants during summer significantly reduced sperm DNA damage to 9.9 ± 4.5% and 7.2 ± 1.6% (P ≤ 0.05) after 42 and 84 days treatment respectively. Total and progressive motility were not altered by the supplement. In summary, sperm DNA integrity is compromised in boars during summer, suggesting boar factors may contribute to seasonal embryo loss in sows. Moreover, such damage appears undetectable using traditional measures of sperm motility. Antioxidant supplementation during summer appears to mitigate the negative impact of heat stress on sperm DNA integrity

Nutritional modelling for enhanced livestock productivity in the rangelands of northern Ghana in response to pasture improvement with an adapted tropical legume species

Low digestibility and crude protein concentrations in native pastures compels some nomadic livestock herders in the rangelands of northern Ghana to burn mature and dry forage to encourage regrowth with better nutritive characteristics. This practice, however, typically leads to pasture scarcity in the dry season (Nov-Apr) so that animals lose weight sometimes leading to mortalities. One possible solution to this problem is to introduce an adapted legume with the aim of increasing protein and dry matter intake during the dry season. Currently, there are no data to support this proposition and provide estimates of likely responses of livestock to the introduction of a legume in this grazing system. The main objective of this study was to use the Grazfeed® program to estimate the potential increase in productivity of lambs in response to incorporation of an adapted tropical legume in native Hyperthelia dissoluta (Yellow thatching grass) pastures typical of northern Ghana. Modelling was conducted for unimproved pasture (0% Legume) and improved pasture (30% legume) for both the dry season (November –April) and wet season (May–October). Values for crude protein (CP) and dry matter digestibility (DMD) were as reported by Skerman and Riveros (1990) (Table 1). Values used for green and dead pasture mass of unimproved pasture ranged from 0 to 1.5 and 1.0 to 1.5 T DM/ha, respectively, in the dry season and 1.0 to 3.5 and 0.5 to 1.0 T DM/ha, respectively, in the wet season. Values used for green and dead pasture mass of improved pasture ranged from 0.5 to 3.0 and 1.0 to 2.0 T DM/ha, respectively, in the dry season and 1.0 to 4.0 and 0.5 to 1.0 T DM/ha, respectively, in the wet season. Lambs were classed as 'small Merino' at 20kg liveweight and an average age of 6 months with 1.5 cm fleece as this was the closest match to the Djallonke breed commonly farmed in Ghana. Modelling suggested acceptable weight gains from native pastures could be expected in the wet and early dry seasons, but with weight loss occurring late in the dry season. This is consistent with observations. Modelling suggested that pasture improvement would result in positive weight gains year round with the largest benefit occurring in the dry season. The study concluded that improving native pastures by incorporating an adapted legume at an average 30% of total dry matter would significantly enhance the productivity of livestock in the rangelands of northern Ghana and would avoid the need for the burning of native pastures in the dry season

A review of pig and poultry diseases in the Eastern Cape Province of South Africa, 2000–2020

The informal poultry and pig sector in the Eastern Cape Province (ECP) of South Africa is of significant socio-economic importance as it sustains livelihoods and ensures food security; yet little is known about the distribution and prevalence of infectious and zoonotic diseases in this region. This paper reviews data published for pig and poultry diseases in the province during the last 20 years (2000–2020). The review included relevant published papers identified by a computerised literature search from Web of Science; provincial animal health reports; the national database from the Department of Agriculture, Land Reform and Rural Development (DALRRD); animal health reports submitted by DALRRD to the World Organisation for Animal Health (OIE) via the World Animal Health Information Database (WAHID) interface and laboratory records. A publication was considered eligible if it included qualitative or quantitative information on any disease affecting pigs and poultry including zoonosis. The search retrieved 174 publications, of which 26 were relevant. The review found that Newcastle disease (ND), coccidiosis and fowl pox (FP) were the most reported avian diseases in the national database, whereas avian infectious bronchitis (AIB), ND and highly pathogenic avian influenza (HPAI) were the most reported diseases in the OIE database. Classical swine fever (CSF) was the most reported pig disease in both databases. The retrieved literature on pig and poultry diseases was scarce and no longer up to date, providing decision makers with little information. The review identified important zoonotic diseases that require further studies yet failed to find information on important neglected diseases like leptospirosis

Mucosal vaccination with a live recombinant rhinovirus followed by intradermal DNA administration elicits potent and protective HIV-specific immune responses

Published: 17 November 2016Mucosal immunity is deemed crucial to control sexual transmission of human immunodeficiency virus (HIV). Herein we report the efficacy of a mucosal HIV vaccine strategy comprising intranasal (IN) vaccination with a cocktail of live recombinant human rhinoviruses (HRVs) encoding overlapping fragments of HIV Gag and full length Tat (rHRV-Gag/Tat) followed by intradermal (ID) vaccination with DNA vaccines encoding HIV Gag and Tat (pVAX-Gag-Tat). This heterologous prime-boost strategy will be referred to hereafter as rHRV-DNA. As a control, IN vaccination with wild type (wt)-HRV-A1 followed by a single ID dose of pVAX (wt-HRV-A1/pVAX vaccination) was included. rHRV-DNA vaccination elicited superior multi-functional CD8(+)T cell responses in lymphocytes harvested from mesenteric lymph nodes and spleens, and higher titres of Tat-specific antibodies in blood and vaginal lavages, and reduced the viral load more effectively after challenge with EcoHIV, a murine HIV challenge model, in peritoneal macrophages, splenocytes and blood compared compared with wt-HRV-A1/pVAX vaccination or administration of 3 ID doses of pVAX-Gag-Tat (3X pVAX-Gag-Tat vaccination). These data provide the first evidence that a rHRV-DNA vaccination regimen can induce HIV-specific immune responses in the gut, vaginal mucosa and systemically, and supports further testing of this regimen in the development of an effective mucosally-targeted HIV-1 vaccine.Khamis Tomusange, Danushka Wijesundara, Jason Gummow, Steve Wesselingh, Andreas Suhrbier, Eric J. Gowans, Branka Grubor-Bau

Cation- and vacancy-ordering in Li_xCoO_2

Using a combination of first-principles total energies, a cluster expansion technique, and Monte Carlo simulations, we have studied the Li/Co ordering in LiCoO_2 and Li-vacancy/Co ordering in CoO_2. We find: (i) A ground state search of the space of substitutional cation configurations yields the (layered) CuPt structure as the lowest-energy state in the octahedral system LiCoO_2 (and CoO_2), in agreement with the experimentally observed phase. (ii) Finite temperature calculations predict that the solid-state order- disorder transitions for LiCoO_2 and CoO_2 occur at temperatures (~5100 K and ~4400 K, respectively) much higher than melting, thus making these transitions experimentally inaccessible. (iii) The energy of the reaction E(LiCoO_2) - E(CoO_2) - E(Li) gives the average battery voltage V of a Li_xCoO_2/Li cell. Searching the space of configurations for large average voltages, we find that CuPt (a monolayer superlattice) has a high voltage (V=3.78 V), but that this could be increased by cation randomization (V=3.99 V), partial disordering (V=3.86 V), or by forming a 2-layer Li_2Co_2O_4 superlattice along (V=4.90 V).Comment: 12 Pages, RevTeX galley format, 5 figures embedded using epsf Phys. Rev. B (in press, 1998

Safety profile of a multi-antigenic DNA vaccine against hepatitis C virus

Despite direct acting antivirals (DAAs) curing >95% of individuals infected with hepatitis C (HCV), in order to achieve the World Health Organization HCV Global Elimination Goals by 2030 there are still major challenges that need to be overcome. DAAs alone are unlikely to eliminate HCV in the absence of a vaccine that can limit viral transmission. Consequently, a prophylactic HCV vaccine is necessary to relieve the worldwide burden of HCV disease. DNA vaccines are a promising vaccine platform due to their commercial viability and ability to elicit robust T-cell-mediated immunity (CMI). We have developed a novel cytolytic DNA vaccine that encodes non-structural HCV proteins and a truncated mouse perforin (PRF), which is more immunogenic than the respective canonical DNA vaccine lacking PRF. Initially we assessed the ability of the HCV pNS3-PRF and pNS4/5-PRF DNA vaccines to elicit robust long-term CMI without any adverse side-effects in mice. Interferon-γ (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) assay was used to evaluate CMI against NS3, NS4 and NS5B in a dose-dependent manner. This analysis showed a dose-dependent bell-curve of HCV-specific responses in vaccinated animals. We then thoroughly examined the effects associated with reactogenicity of cytolytic DNA vaccination with the multi-antigenic HCV DNA vaccine (pNS3/4/5B). Hematological, biochemical and histological studies were performed in male Sprague Dawley rats with a relative vaccine dose 10–20-fold higher than the proposed dose in Phase I clinical studies. The vaccine was well tolerated, and no toxicity was observed. Thus, the cytolytic multi-antigenic DNA vaccine is safe and elicits broad memory CMI.Jason Gummow, Makutiro G. Masavuli, Zelalem A. Mekonnen, Yanrui Li, Danushka K. Wijesundara, Ashish C. Shrestha, Ilia Voskoboinik, Eric J. Gowans and Branka Grubor-Bau

Enhanced T cell responses induced by a necrotic dendritic cell vaccine, expressing HCV NS3

A vaccine that induces potent, broad and sustained cell-mediated immunity, resulting in effective memory has the potential to restrict hepatitis C (HCV) virus infection. Early, multi-functional CD4+ and CD8+ T cell responses against non-structural protein 3 (NS3) have been associated with HCV clearance. Necrotic cells generate strong immune responses and represent a major antigenic source used by dendritic cells (DC) for processing and presentation, but there is conflicting evidence as to their immunogenicity in vaccination. Immunization with DC loaded with viral antigens has been done in the past, but to date the immunogenicity of live vs. necrotic DC vaccines has not been investigated. We developed a DC2.4 cell line stably expressing HCV NS3, and compared the NS3-specific responses of live vs. necrotic NS3 DC. Vaccination of mice with necrotic NS3 DC increased the breadth of T-cell responses and enhanced the production of IL-2, TNF-α, and IFN-γ by effector memory CD4+ and CD8+T cells, compared to mice vaccinated with live NS3 DC. A single dose of necrotic NS3 DC vaccine induced a greater influx and activation of cross-presenting CD11c+ CD8α+ DC and necrosis-sensing Clec9A+ DC in the draining lymph nodes. Furthermore, using a hydrodynamic challenge model necrotic NS3 DC vaccination resulted in enhanced clearance of NS3-positive hepatocytes from the livers of vaccinated mice. Taken together, the data demonstrate that necrotic DC represent a novel and exciting vaccination strategy capable of inducing broad and multifunctional T cell memory.Zelalem A. Mekonnen, Makutiro G. Masavuli, Wenbo Yu, Jason Gummow, Dawn M. Whelan, Zahraa Al-Delfi ... et al

First principles electronic structure of spinel LiCr2O4: A possible half-metal?

We have employed first-principles electronic structure calculations to examine the hypothetical (but plausible) oxide spinel, LiCr2O4 with the d^{2.5} electronic configuration. The cell (cubic) and internal (oxygen position) structural parameters have been obtained for this compound through structural relaxation in the first-principles framework. Within the one-electron band picture, we find that LiCr2O4 is magnetic, and a candidate half-metal. The electronic structure is substantially different from the closely related and well known rutile half-metal CrO2. In particular, we find a smaller conduction band width in the spinel compound, perhaps as a result of the distinct topology of the spinel crystal structure, and the reduced oxidation state. The magnetism and half-metallicity of LiCr2O4 has been mapped in the parameter space of its cubic crystal structure. Comparisons with superconducting LiTi2O4 (d^{0.5}), heavy-fermion LiV2O4 (d^{1.5}) and charge-ordering LiMn2O4 (d^{3.5}) suggest the effectiveness of a nearly-rigid band picture involving simple shifts of the position of E_F in these very different materials. Comparisons are also made with the electronic structure of ZnV2O4 (d^{2}), a correlated insulator that undergoes a structural and antiferromagnetic phase transition.Comment: 9 pages, 7 Figures, version as published in PR