Pig Production Research Articles

Semiquantitative Risk Evaluation Reveals Drivers of African Swine Fever Virus Transmission in Smallholder Pig Farms and Gaps in Biosecurity, Tanzania

African swine fever (ASF) has remained persistent in Tanzania since the early 2000s. Between 2020 and 2021, pig farms in twelve districts in Tanzania were infected with ASF, and ≥4,804 pigs reportedly died directly due to the disease with disruption to livelihoods. We conducted semiquantitative field investigations and rapid risk assessment (RRA) to understand the risk factors and drivers of ASF virus (ASFV) amplification and transmission in smallholder pig farms, and determine the gaps in biosecurity through hazard profiling, focus group discussions and expert opinion. Outbreaks were connected by road and aligned along the pig product value chain and reported in the northern, central, and southern parts of Tanzania. The patterns of outbreaks and impacts differed among districts, but cases of ASF appeared to be self-limiting following significant mortality of pigs in farms. Movement of infected pigs, movement of contaminated pig products, and fomites associated with service providers, vehicles, and equipment, as well as the inadvertent risks associated with movements of animal health practitioners, visitors, and scavengers were the riskiest pathways to introduce ASFV into smallholder pig farms. Identified drivers and facilitators of risk of ASFV infection in smallholder pig farms were traders in whole pigs, middlemen, pig farmers, transporters, unauthorized animal health service providers, and traders in pork. All identified pig groups were susceptible to ASFV, particularly shared adult boars, pregnant and lactating sows, and other adult females. The risk of ASF for smallholder pig farms in Tanzania remains very high based on a systematic risk classification. The majority of the farms had poor biosecurity and no single farm implemented all identified biosecurity measures. Risky practices and breaches of biosecurity in the pig value chain in Tanzania are profit driven and are extremely difficult to change. Behavioural change communication must target identified drivers of infections, attitudes, and practices.

Effects of mimicking manure removal strategies on ammonia and greenhouse gas emissions in sow pen scale models

With growing concerns about air pollution and global warming effects, the emissions of NH3 and greenhouse gases (GHGs) have become significant issues in the pig production industry. In order to discover whether optimizing manure removal strategies could alter the manure decomposition process and benefit the reduction of gas emissions, a scale model approach was used to quantify the gas emissions under controlled conditions. This study compared the gas emission reduction potential of two classic manure removal systems (scraper and pull-plug system) in three manure removal strategies: scraper-I (retaining manure for 24 h), scraper-II (retaining manure for 8 and 16 h) and pull-plug (retaining manure for 44 days). Fresh urine and faeces collected from a gestation sow house were applied to the scale models and then removed through the manure removal systems. The concentrations of gases (NH3, CH4, CO2, and N2O) within the scale model and removed slurry samples were collected and analysed (pH, electric conductivity, dry matter, total nitrogen, total ammonium nitrogen and total carbon). The results showed that emissions of CH4, CO2, and N2O from scraper-I were on average 54%, 56% and 25% lower than those from scraper-II, and 71%, 67% and 6% lower than those from pull-plug treatment, respectively. The GHGs emission rates (as CO2-equivalents) of scraper-I and scraper-II were 52% and 26.3% lower than that of pull-plug treatment respectively (P < 0.01). The emissions of NH3 displayed a temporary peak during each application of urine and removal of manure. In pull-plug treatment, the concentrations of NH3, CH4, and CO2 exponentially increased between Day 39 and Day 41. The nitrogen content, both total nitrogen and total ammonium nitrogen, within the slurry under the scraper system exhibited lower values compared to those from the pull-plug system. Conversely, the total carbon content was higher in the former system. Caution is warranted in extrapolating results to full-scale pig housing, given study limitations (e.g. small scale, mimicked scraper activity, no animals, etc.). Nevertheless, the conclusions and findings of this study provide fundamental data for understanding gas emissions from pig house manure management. This insight can guide the design and daily operations of low-emission manure removal systems in gestation sow houses.

Rapid Detection and Quick Characterization of African Swine Fever Virus Using the VolTRAX Automated Library Preparation Platform

Rapid Detection and Quick Characterization of African Swine Fever Virus Using the VolTRAX Automated Library Preparation Platform

119 Bentley Lecture: Gene editing: A Japanese perspective

Abstract Development of useful gene editing technologies, such as ZFN, TALEN and CRISPR/Cas9 systems, has made it possible to efficiently produce knock-out and knock-in mammals, including domestic animals. In particular, the number of scientific papers on gene editing by using the CRISPR/Cas9 system has increased rapidly since 2013, although it has begun to decline from 2022. Among those researchers, the contribution of Japanese scientists accounts for 5 to 10% of the total number of published papers in many species, including laboratory and domestic animals, while those in rats account for nearly 20 % of the total. Whereas research results in rodents, such as mice and rats, have been published from many Japanese institutions, those in domestic animals, such as pigs, appears to be from only limited numbers. With regard to the application of gene editing technology to livestock species, only pigs have different objectives compared with other species, and are used for xenotransplantation and disease models rather than for industrial applications. Whereas this trend is also true for research in Japan, publications on the attempts of new methodologies seem to stand out. A distinctive feature of Japanese research on mammalian gene editing may be the development of methods to introduce gene editors into oocytes with electroporation, for example, GEEP and iGonad, and the applications. These methods seem to be used to generate knock-out animals efficiently, and production of pigs with simultaneous knockout of two or three genes has been reported. To produce knock-in pigs, however, it seems that cloned animals still need to be produced by nuclear transplantation of somatic cells in which the interested gene has been previously modified. Although the attempts to introduce editing tools directly into zygotes by microinjection, which is much simpler than somatic cell nuclear transplantation, have been reported, it has not been controlled yet to reduce the occurrence of mosaics, and it would be necessary to wait for further improvement. In addition, some methods for gene editing chemically or by lipofection have also been attempted, but the efficiencies may still need to be improved. Arrangements for the proper handling of gene-edited animals and food products by Japanese government, especially whether or not such animals and food products are genetically modified organisms, etc. as defined by law, will have a significant impact on the direction and promotion of research on gene editing in Japan.

66 A novel analytical method for identifying periods of increased mortality in individual wean-to-finish pig barns

Abstract Mortality rates in all phases of pork production have increased over the past several years. Decreasing mortality rate is of utmost economic importance to producers, especially in weaning-to-finishing pigs where additional investment in feed, medications, and other inputs are expended. A novel analytical method was used to identify sequences of days of increased mortality, defined as mortality episodes, within cohorts of weaning-to-finishing pigs. Cubic smoothing spline regression equations were estimated between days post placement (DPP) and mortality (total daily number of dead and euthanized pigs) for 42 groups of pigs placed in 12 rooms within 6 barns (2 rooms per barn) in Illinois and Iowa from December 2020 to July 2022 (n = 5,676 observation days). For each group, the instantaneous slope between DPP and mortality from spline regression was calculated and used to identify changepoints [i.e., peaks (negative instantaneous slope at DPPt and positive instantaneous slope at DPPt-1) and valleys (positive instantaneous slope at DPPt and negative instantaneous slope at DPPt-1)]. Within each mortality sequence, the maximum and minimum instantaneous slope were considered the start and end of the mortality episode, respectively. Mortality episodes were only considered high mortality episodes if the following metrics were satisfied: 1) greater than or equal to 1 mortality per day, or 2) greater than or equal to 1/3 of the days in the mortality sequence had at least 1 mortality. Days were classified as “start days” if they were within 1 d from the maximum instantaneous slope; likewise, we classified a day as “end days” if it was 1 d from the minimum instantaneous slope. Any day in between the start and end of a mortality episode were defined as “peak days”, and a “normal day” was all other days that did not fall within the start, peak, or end of a high mortality episode. Least-squares means for predicted mortality from a negative binomial generalized linear model showed that mortality was highest and lowest for peak days and normal days, respectively (3.475 ± 0.1729 and 0.591 ± 0.0156 pigs, respectively; P &amp;lt; 0.05; Table 1). Mortality during start or end days of an episode did not differ from each other (2.185 ± 0.1973 and 2.069 ± 0.1881 pigs, respectively; P &amp;gt; 0.05; Table 1) but were significantly greater and lower than a normal or peak day, respectively (P &amp;lt; 0.05; Table 1). The proposed analytical method provides more precise classification of mortality episodes in pig cohorts than previously proposed methods. Results from this method can be used in models to predict the start of mortality episodes, providing ample time for intervention to reduce the overall number of dead pigs in wean-to-finish pig production.

126 A nutritional solution based on calcidiol (25-OH-D3, HyD) and triterpenoid affects muscle protein synthesis pathways in grower-finisher pigs

Abstract To boost profitability in pig production, it is important to achieve increased lean growth rates and maximize efficiency, especially in grower-finisher pigs where feed intakes are high. Molecular research, especially the study of gene expression, is a proven tool for understanding the precise mechanisms behind muscle tissue growth, including a recent focus on pathways such as the mammalian target of rapamycin (mTOR). In the current work, gene expression analyses were used to study the mode of action of the combination of calcidiol (25-OH-D3, HyD) and triterpenoid, which has shown significant growth and efficiency improvements in grower-finisher pigs (McCormack et al., 2024). Three experimental diets were evaluated for 7 wk; Positive control: 0.7% total Ca, 0.36% total P, vit D3 at 1500IU/kg feed (PC), negative control: PC diet + 30% reduced Ca and 10% reduced P (NC), and NC diet with 1,500IU D3 in calcidiol form (25-OH-D3, HyD) and triterpenoid (NC+). At 19 wk of age, 16 animals per treatment were sacrificed and tissue samples were taken from the longissimus muscle and preserved in RNA later solution. The RNA was extracted, quality control checked, and mRNA sequenced using the Illumina platform with 150 base pair paired-end sequencing and 30M read depth. The sequenced data were aligned to the Sus scrofa reference genome (Sscrofa11.1) using Kallisto. Data were normalized and analyzed for differentially expressed genes (DEGs) between treatments using DeSeq2. Genes were assigned to biological pathways using Biofractal’s customisation of the Reactome pathway database. For statistical analysis, RNA integrity number and treatment were included in the model. In the PC compared with the NC, there were 71 DEGs using a false discovery rate (FDR) of &amp;lt; 0.10. Altered pathways included the inhibition of cellular stress pathways and increased cell turnover in the muscle of PC compared with NC pigs. In the NC+ compared with the NC, there were 155 DEGs (FDR &amp;lt; 0.10). The most significantly upregulated gene in the NC+ treatment was adenylate cyclase (FDR &amp;lt; 0.001), an upstream regulator of several pathways related to energy metabolism and muscle protein synthesis. This mechanism was confirmed in the pathway analysis, which found that the NC+ treatment activated PKA-mediated phosphorylation of CREB, a pathway that inhibits muscle atrophy. Furthermore, the NC+ treatment activated several pathways related to muscle growth, including the mammalian target of rapamycin complex 1 (mTORC1). In this study the addition of calcidiol (25-OH-D3, HyD) and triterpenoid to the diet was found to specifically affect molecular pathways in the muscle of grower-finisher pigs involved in both the inhibition of muscle breakdown as well as activating muscle growth.

117 Gene editing on the farm: Current status and future prospects

Abstract Livestock with enhanced disease resistance genes offer both health advantages to animals and economic opportunities for farmers aiming to meet the rising demand for affordable, high-quality protein. This study builds upon prior research that utilized gene editing to modify the porcine CD163 gene, demonstrating resistance to the RNA virus responsible for porcine reproductive and respiratory syndrome (PRRS). To amplify the impact of this disease resistance trait, it is crucial for it to be present in commercially significant breeding populations, facilitating the widespread production and distribution of resistant pigs. In pursuit of this objective, a groundbreaking gene editing program was implemented, leveraging CRISPR-Cas technology, next-generation DNA sequencing, in vitro and in vivo off-target analyses, whole-genome sequencing (WGS), and a simplified breeding strategy. This innovative approach aimed to introduce a single modified CD163 allele into four genetically elite and diverse porcine lines, rendering the cells and animals resistant to PRRS virus (PRRSV) infection. The resulting founder population is currently undergoing large-scale phenotype testing, multiplication through classical breeding methods, ongoing genetic refinement, and poised for commercialization pending regulatory approvals. This presentation will provide insights into the process and data associated with this scaled production, marking a significant stride towards the realization of commercially elite PRRS virus resistant pigs.

Animal geographies of industrial animal agriculture in the Pandemic Era: the tragedy and insecurity of multispecies ethnography

ABSTRACT Amidst the capitalist logics governing life and death in the industrial production of pigs and poultry in Denmark, we confront the ethico-methodological challenges of conducting multispecies research in this time of increased pathogen emergence and transmission: the ‘Pandemic Era’. Drawing on our empirical insights, we contend that worldly animal geographies in the Pandemic Era are constituted by biological and existential insecurity, underscoring the importance of this work. Through affectively attuning to the bordering devices of biosecurity, we convey the capaciousness of performative understandings of species that industrial agriculture constrains but which animal geographers can advance. Acts of witnessing in industrial agriculture expose the limitations of multispecies ethnography that simultaneously catalyse advancement in the field. Whilst our work reckons with the tragedy of multispecies ethnography in industrial landscapes, the limits we have encountered, from the methodological to the ethical, are incitements to critique and innovate modes of attunement that extend beyond the field of animal geographies itself.

128 Effects of dietary hybrid rye on quality and consumer acceptability of pork from pigs raised under organic conditions

Abstract In organic pig production, hybrid rye grain and straw can be used as feed and bedding, respectively, to reduce production costs. However, there is a concern that replacing corn with hybrid rye in pig diets may affect pork quality. In this study, we investigated whether inclusion of hybrid rye in pig diets can affect quality and consumer acceptability of pork from organically raised pigs. Pigs [n = 200, initial body weight (BW) = 26.8±3.5 kg, 10 wk of age] were assigned to Control or Rye treatments (50 pigs/pen; 2 pens/treatment) within a hoop barn and stratified for BW and sex across pens. Control pigs received corn, soybean meal-based diets. Rye pigs were fed diets in which hybrid rye replaced 50% of the corn in control diets. Near market BW (average = 127 kg, 22 wk of age), 8 pigs per pen (4 barrows and 4 gilts) closest to the average BW of all pigs in the pen were selected for evaluation of pork quality and consumer acceptability. Carcass pH at 45 min and 24 h postmortem in the ham, and objective color scores (L*, a*, b*), shear force, and subjective color and marbling scores were collected from a loin chop. Loin chops were kept at or below -18°C until a consumer taste panel was conducted to assess overall liking, flavor liking, texture liking, toughness, juiciness, and off-flavor of pork from the cooked loin chops. Liking ratings were made on 120-point scales (0 - strongest dislike imaginable, 120 - strongest like imaginable). Toughness, juiciness, and off-flavor were ranked on 20-point scales (0 - none, 20 - extremely tough, juicy, or intense, respectively). Data were analyzed using the Mixed procedure, Frequency procedure with chi-square test of SAS. Measures of pork quality (pH at 45 min and 24 h, a*, b*, shear force, and subjective marbling and color scores) were not different between treatments (Table 1). Pigs fed Control diets displayed a greater (P = 0.006) L* reading than Rye-fed pigs indicating that pork from Control pigs was lighter in color than Rye-fed pigs. Generally, the taste panel did not detect a difference in acceptability of pork from Control and Rye-fed pigs. Juiciness and off flavor were scored very similarly by panelists. However, pork from Rye-fed pigs tended (P = 0.075) to be tougher than pork from Control pigs. Liking attributes (overall liking, flavor liking, and texture liking) were scored similarly between Rye-fed and Control pigs and generally better than neutral (neutral=60/120) by panelists. These data suggest that replacing 50% of corn with hybrid rye in diets for growing-finishing pigs will not negatively impact quality or consumer acceptability of pork.

151 Use of a clay and algae-based decontaminant on sows naturally exposed to mycotoxins in gestation and lactation

Abstract Mycotoxin contamination in pig feed is a recurring problem leading to chronic exposure of the animals, even when mycotoxin levels are below official guidance (FDA, EFSA). Deoxynivalenol (DON) and its derivates are among the main mycotoxins impacting pig production in the United States. This study evaluated the effect of a clay- and algae-based mycotoxin decontaminant on the reproductive performance of sows (n = 207) exposed to chronic natural mycotoxin contamination from 35 d of gestation to weaning. The level of mycotoxins in the feed was measured using LC-MS/MS. A mean contamination of 956 ppb DON, 125 ppb 15-o-acteyl-DON, 338 ppb fumonisins B1 + B2 and 62 ppb zearalenone was reported. Despite a comparable starting body weight (BW) between the control (without decontaminant) and test (with decontaminant) groups at allotment (P = 0.67), sows in the test group had a greater BW than the control sows at entry in farrowing (P &amp;lt; 0.01), and a body condition score of 0.12 points greater (P = 0.04). More live-born piglets were observed in supplemented sows than in control sows (+4%; P &amp;lt; 0.01), as well as a smaller proportion of mummified and stillborn piglets (-39%; P &amp;lt; 0.05 and -34%, P &amp;lt; 0.01, respectively). In contrast, the BW and growth of piglets before weaning did not differ between groups (P &amp;gt; 0.10). These results indicate that the tested decontaminant can improve the body condition and farrowing performance of mycotoxin-exposed sows at levels below current recommendations.

201 The effects of the supplementation of a Zinc-amino acid complex in pig nursery diets with differing pharmacological levels of zinc oxide and complexity

Abstract Diet complexity (DC), which has significance in nursery pig production, generally refers to a greater number of highly digestible ingredients. Increased DC may have even greater significance in scenarios of reduction or withdrawal of zinc oxide (ZnO) in nursery diets. The objectives were to determine 1) the impact of adding Zn-amino acid complex (Zinpro ProPath Zn) to mid- (MC) and low-complexity (LC) diets on nursery pig performance and health compared with a high complexity (HC) diet, and 2) the impact of Zinpro ProPath Zn in diets with and without pharmacologic levels of ZnO. A total of 2,400 mixed-sex weanling pigs [initial body (BW) weight = 5.79 ± 0.15 kg] were assigned to 1 of 5 dietary treatments during nursery (42 d) as follows: 1) HC; MC diet with 2) MC+ZnO) or without 3) MC-ZnO) pharmacologic ZnO; and LC diet with 4) LC+ZnO) or without 5) LC-ZnO) pharmacologic ZnO. All diets except HC were supplemented with Zinpro ProPath Zn (125 mg/kg Zn) and ZnO [3,000, 2,000, and 0 mg/kg Zn during Phases I (14 d), II (14 d) and III (14 d), respectively]. Different DC were achieved by manipulating the inclusion of spray-dried plasma, soy protein concentrate, and whey protein. Growth performance, onset of feed intake, fecal dry matter, number of injectable treatments administered, and serum acute-phase response were assessed. Pigs fed HC (20.0 kg) had greater final BW (FBW) compared with pigs fed MC-ZnO (18.8 kg), which had greater FBW compared with pigs fed LC-ZnO (17.5 kg; SEM = 0.34; P &amp;lt; 0.05). Average daily feed intake (ADFI) was greater in pigs fed HC (0.46 kg/d) compared with MC-ZnO (0.43 kg/d) and LC+ZnO (0.42 kg/d), which had greater ADFI compared with LC-ZnO (0.39 kg/d; SEM = 0.01; P &amp;lt; 0.05). Similarly, average daily gain (ADG) and gain to feed ratio (G:F) were greater in pigs fed HC (0.33 kg/d, 0.72 kg/kg, respectively) compared with pigs fed LC (0.27 kg/d, 0.67 kg/kg, respectively), regardless of ZnO (SEM = 0.01; P &amp;lt; 0.05). There was no effect of dietary treatments on the fecal dry matter or on the onset of feed intake of pigs (P &amp;gt; 0.10). The number of injectable treatments administered was greatest in LC-ZnO (62.7%), followed by LC+ZnO (50.6%), MC regardless of ZnO (44.0%), and HC (36.7%; SEM = 1.04; P &amp;lt; 0.05). Serum alkaline phosphatase was less in LC-ZnO than the other groups (229.8 vs. 280.9 ± 11.9 IU/L; P &amp;lt; 0.05). Taken together, feeding HC diets during the nursery appears to be effective in improving performance and health of pigs, particularly when compared with MC and LC diets without ZnO. Moreover, the addition of Zinpro ProPath Zn may partially attenuate the negative effects of ZnO removal in MC, but not LC, diets.

The Role of the MYL4 Gene in Porcine Muscle Development and Its Molecular Regulatory Mechanisms.

Muscle growth stands as a pivotal economic trait within pig production, governed by a complex interplay of multiple genes, each playing a role in its quantitative manifestation. Understanding the intricate regulatory mechanisms of porcine muscle development is crucial for enhancing both pork yield and quality. This study used the GSE99749 dataset downloaded from the GEO database, conducting a detailed analysis of the RNA-seq results from the longissimus dorsi muscle (LD) of Tibetan pigs (TP), Wujin pigs (WJ) and large white pigs (LW) at 60 days of gestation, representing diverse body sizes and growth rates. Comparative analyses between TPvsWJ and TPvsLW, along with differential gene expression (DEG) analysis, functional enrichment analysis, and protein-protein interaction (PPI) network analysis, revealed 1048 and 1157 significantly differentially expressed genes (p < 0.001) in TPvsWJ and TPvsLW, respectively. With stricter screening criteria, 37 DEGs were found to overlap between the 2 groups. PPI analysis identified MYL5, MYL4, and ACTC1 as the three core genes. This article focuses on exploring the MYL4 gene. Molecular-level experimental validation, through overexpression and interference of the MYL4 gene combined with EDU staining experiments, demonstrated that overexpression of MYL4 significantly promoted the proliferation of porcine skeletal muscle satellite cells (PSMSC), while interference with MYL4 inhibited their proliferation. Furthermore, by examining the effects of overexpressing and interfering with the MYL4 gene on the muscle hypertrophy marker Fst gene and the muscle degradation marker FOXO3 gene, the pivotal role of the MYL4 gene in promoting muscle growth and preventing muscle degradation was further confirmed. These findings offer a new perspective on the molecular mechanisms behind porcine muscle growth and development, furnishing valuable data and insights for muscle biology research.

Brief research report: the evolution of animal welfare legislation for pigs in 13 EU member states, 1991-2020

This brief report characterizes and maps changes in six key aspects of pig animal welfare (AW) legislation in 13 countries in the European Union (EU) during the period 1991-2020, focusing primarily on aspects of AW likely to impact the economic performance and international competitiveness of the pig production sector. National AW legislation in the selected EU member states that exceed the EU minimum levels within the six selected key areas are also mapped. Analysis of changes in AW over time, using legislative texts, academic literature, and an expert survey, revealed that AW-legislation at the national level has generally become more stringent, in line with EU directives, and that a number of member states have introduced additional AW legislation that exceed EU minimum levels. This review helps to uncover historical changes in and can form the basis for further research investigating effects of changes in AW legislation.

Protecting the piglet gut microbiota against ETEC-mediated post-weaning diarrhoea using specific binding proteins

Post-weaning diarrhoea (PWD) in piglets presents a widespread problem in industrial pig production and is often caused by enterotoxigenic E. coli (ETEC) strains. Current solutions, such as antibiotics and medicinal zinc oxide, are unsustainable and are increasingly being prohibited, resulting in a dire need for novel solutions. Thus, in this study, we propose and evaluate a protein-based feed additive, comprising two bivalent heavy chain variable domain (VHH) constructs (VHH-(GGGGS)3-VHH, BL1.2 and BL2.2) as an alternative solution to manage PWD. We demonstrate in vitro that these constructs bind to ETEC toxins and fimbriae, whilst they do no affect bacterial growth rate. Furthermore, in a pig study, we show that oral administration of these constructs after ETEC challenge reduced ETEC proliferation when compared to challenged control piglets (1-2 log10 units difference in gene copies and bacterial count/g faeces across day 2–7) and resulted in week 1 enrichment of three bacterial families (Prevotellaceae (estimate: 1.12 ± 0.25, q = 0.0054), Lactobacillaceae (estimate: 2.86 ± 0.52, q = 0.0012), and Ruminococcaceae (estimate: 0.66 ± 0.18, q = 0.049)) within the gut microbiota that appeared later in challenged control piglets, thus pointing to an earlier transition towards a more mature gut microbiota. These data suggest that such VHH constructs may find utility in industrial pig production as a feed additive for tackling ETEC and reducing the risk of PWD in piglet populations.

Production of cleavage-resistant phytase transgenic pigs by handmade cloning

With the rapid development of intensive animal husbandry in the livestock industry, large quantities of manure waste containing phytate phosphorus are being generated. Phytase can effectively solve the problem of high phosphorus pollution in the feces of monogastric animals. Enviropig, which produces phytase in the salivary glands and secretes the enzyme in the saliva, were first generated in 1999. However, phytase is easily inactivated during digestion. To address this problem, cleavage-resistant phytase transgenic pigs were generated using handmade cloning in this study. Transgene construction was improved and three cell lines carrying Cafp were obtained. In total, 810 blastocysts were generated and 712 good-quality were transferred into six recipients. Fourteen piglets were born, of which six survived after weaning. Polymerase chain reaction and sequencing results showed that seven (three live and four dead) of the fourteen piglets carried Cafp. Phytase activity in the saliva of the six live cloned pigs was tested at four months of age, and only one pig had 0.155 FTU/mL enzyme activity. The other five pigs may not have been activated in the transgenic parotid gland. Among all the transgenic pigs, the highest phosphorus digestion rate was 59.2% of intake, representing a 25.4% decrease in fecal emission compared to the average of controls. Immunohistochemical results on the three Cafp-positive pigs that died after six months of age showed that the transgene was only expressed in parotid glands, confirming tissue-specific gene expression. In conclusion, cleavage-resistant phytase transgenic pigs were successfully produced through handmade cloning. The cloned pigs offer a unique biological approach to managing phosphorus nutrition and environmental pollution in animal husbandry.

An economic assessment of alternative antimicrobial use scenarios on pig farms.

This paper explores the theoretical economic outcome of management changes that result in different levels of antimicrobial use (AMU) in two types of UK pig farm. A static farm economic pig production model (FEPM) was used on a representative 'Top-third' most profitable farm and a representative 'Mid-range' profitable farm. Three AMU theoretical management scenarios were investigated; (a) management changes leading to a reduction of AMU by 35% (AMU35); (b) more extensive management changes leading to a reduction of AMU by 95% (AMU95); and (c) implementing depopulation of the herd (AMU Depop). A sensitivity analysis was conducted to determine the effect of increases or decreases in pig revenue and feed price on farm gross margin under these scenarios. Over a single year, the AMU35 scenario was estimated to have a small positive impact (+3%) on both farm types. The other two AMU reduction scenarios had higher AMU reduction on farms but required higher variable cost and hence they resulted in lower farm profitability. There was a substantial reduction (up to -50%) in farm gross margin under these two AMU reduction scenarios in the modeled short-term time-period. The impact of the alternative AMU scenarios was slightly higher on a farm representing the 'Top-third' farm type, reducing farm gross margin further by 7% compared to the 'Mid-range' farm. Nevertheless, both farm types stay profitable under all three AMU scenarios. The results showed that in the modeled short-term implementing management changes that result in a reduction of on-farm AMU by 35% had a good economic outcome. In practice, the other two scenarios would be considered as longer-term strategies. Although both require higher initial costs to implement, the improved biosecurity and hygiene will benefit from lower disease occurrence for a longer term. Farm gross margins were, however, found to be highly sensitive to changes on market prices especially increasing feed prices. An increase of more than 15% in feed price moved a profitable farm into a loss-making farm. It will be economically challenging for uptakes of these, or similar, AMU reduction scenarios on farms if the market prices become un-favorable to pig farmers.

Antiviral screening of natural, anti-inflammatory compound library against African swine fever virus

BackgroundAfrican swine fever virus (ASFV) is a major threat to pig production and the lack of effective vaccines underscores the need to develop robust antiviral countermeasures. Pathologically, a significant elevation in pro-inflammatory cytokine production is associated with ASFV infection in pigs and there is high interest in identifying dual-acting natural compounds that exhibit antiviral and anti-inflammatory activities.MethodsUsing the laboratory-adapted ASFV BA71V strain, we screened a library of 297 natural, anti-inflammatory compounds to identify promising candidates that protected Vero cells against virus-induced cytopathic effect (CPE). Virus yield reduction, virucidal, and cell cytotoxicity experiments were performed on positive hits and two lead compounds were further characterized in dose-dependent assays along with time-of-addition, time-of-removal, virus entry, and viral protein synthesis assays. The antiviral effects of the two lead compounds on mitigating virulent ASFV infection in porcine macrophages (PAMs) were also tested using similar methods, and the ability to inhibit pro-inflammatory cytokine production during virulent ASFV infection was assessed by enzyme-linked immunosorbent assay (ELISA).ResultsThe screen identified five compounds that inhibited ASFV-induced CPE by greater than 50% and virus yield reduction experiments showed that two of these compounds, tetrandrine and berbamine, exhibited particularly high levels of anti-ASFV activity. Mechanistic analysis confirmed that both compounds potently inhibited early stages of ASFV infection and that the compounds also inhibited infection of PAMs by the virulent ASFV Arm/07 isolate. Importantly, during ASFV infection in PAM cells, both compounds markedly reduced the production of pro-inflammatory cytokines involved in disease pathogenesis while tetrandrine had a greater and more sustained anti-inflammatory effect than berbamine.ConclusionsTogether, these findings support that dual-acting natural compounds with antiviral and anti-inflammatory properties hold promise as preventative and therapeutic agents to combat ASFV infection by simultaneously inhibiting viral replication and reducing virus-induced cytokine production.

Enhancement of selectivity, 25-hydroxyvitamin D3 level, alkaline phosphatase activity and reproductive performance in gilts and primiparous sows using 14-epimer of 25-hydroxyvitamin D3

Selecting breed-worthy gilts as sow replacements is essential for continuity of pig production cycle. Though vitamin D3 (VD3) is known to enhance reproductive performance of multiparous sows, there is still a knowledge gap on its impact in developing gilts and primiparous sows. This study was aimed to quantify plasma 25-hydroxyvitamin D3 (25(OH)D3), serum alkaline phosphatase (ALP), and examine the reproductive performance of primiparous sows fed diets supplemented with regular VD3, and its 25(OH)D3 epimers. The study sample comprised 10-week-old replacement gilts (50 % Landrace x 50 % Yorkshire, N = 180) assigned in a randomized complete block design to three treatments [2,000 IU/kg of VD3 (T1), 25 µg/kg of 14‑epi-25(OH)D3, half dose (T2), and 50 µg/kg of 25(OH)D3 (T3)] equilibrated to 2,000 IU/kg in base diets. Selections occurred at 22, 27 and 35 weeks of age, respectively. Plasma 25(OH)D3, serum alkaline phosphatase (ALP), bone structure and reproductive performance were analyzed. Dietary treatments influenced carpus (P = 0.023), fore view stance (P = 0.017), infantile vulva (P = 0.014), inverted (P = 0.048), and prominent teat (P < 0.001). Post-partum 25(OH)D3 concentration and ALP activity were elevated by day 25 (P < 0.001). Treatment diets also influenced total born (P < 0.001), born alive (P = 0.048), and still born (P = 0.049). Two factors affect circulating 25(OH)D3 and ALP activity: physiological changes in sows during lactation, and dietary 25(OH)D3 intake. 14‑epi-25(OH)D3 is a potent metabolite for improving maturation of reproductive organs in developing gilts. It also reduces still birth in primiparous sows.

The Role of β3-Adrenergic Receptors in Cold-Induced Beige Adipocyte Production in Pigs.

After exposure to cold stress, animals enhance the production of beige adipocytes and expedite thermogenesis, leading to improved metabolic health. Although brown adipose tissue in rodents is primarily induced by β3-adrenergic receptor (ADRB3) stimulation, the activation of major β-adrenergic receptors (ADRBs) in pigs has been a topic of debate. To address this, we developed overexpression vectors for ADRB1, ADRB2, and ADRB3 and silenced the expression of these receptors to observe their effects on the adipogenic differentiation stages of porcine preadipocytes. Our investigation revealed that cold stress triggers the transformation of subcutaneous white adipose tissue to beige adipose tissue in pigs by modulating adrenergic receptor levels. Meanwhile, we found that ADRB3 promotes the transformation of white adipocytes into beige adipocytes. Notably, ADRB3 enhances the expression of beige adipose tissue marker genes, consequently influencing cellular respiration and metabolism by regulating lipolysis and mitochondrial expression. Therefore, ADRB3 may serve as a pivotal gene in animal husbandry and contribute to the improvement of cold intolerance in piglets.

Influence of Fermented Mulberry Leaves as an Alternative Animal Feed Source on Product Performance and Gut Microbiome in Pigs

Mulberry leaves are rich in nutrients but contain anti-nutrient factors that hinder their digestion and absorption. Feeding animals with mulberry leaves directly could harm their health. The microbial fermentation of mulberry leaves could reduce their anti-nutritional factors’ content and improve their nutritional value. Sequencing and analyzing mulberry leaves before and after fermentation showed that fermentation increased the relative abundance of Pediococcus, Bradyrhizobium, Hydrotalea, and Rhodanobacteria, and decreased that of Enterobacter. Fermentation improved the quality of mulberry leaves by rebuilding the bacterial community. Finishing pigs were raised on fermented mulberry leaves (FML), and their carcass performance, meat quality, economic benefits, and gut microbiome were evaluated. FML had no negative impact on pig carcass performance, meat quality, and antioxidant capacity, and could somewhat improve the economic benefits. FML decreased the relative abundance of Proteobacteria in the colon and Streptococcus in the feces, and increased that of Actinobacteria (cecum, colon, feces) and Prevotella (colon). The gut core microorganisms in the FML group were mainly enriched with Actinobacteria, Bifidobacterium, Bifidobacteriaceae, Bifidobacteriales, and other beneficial microorganisms. Dietary FML reduced ammonia, indole, and skatole contents in the feces. In conclusion, FML reshaped the gut microbiota without negatively affecting pig product performance, produced cleaner waste, and improved environmental protection and sustainability, making it an attractive prospective feed for pigs.