Weaning age and its effect on the development of the swine gut microbiome and resistome

Piglets are often weaned between 19 and 22 d of age in North America although in some swine operations this may occur at 14 d or less. Piglets are abruptly separated from their sow at weaning and are quickly transitioned from sow's milk to a plant-based diet. The effect of weaning age on the long-term development of the pig gut microbiome is largely unknown. In this study, pigs were weaned at either 14, 21, or 28 d of age and fecal samples collected 21 times from d 4 (neonatal) through to marketing at d 140. The fecal microbiome was characterized using 16S rRNA gene and shotgun metagenomic sequencing. The fecal microbiome of all piglets shifted significantly three to seven days post-weaning with an increase in microbial diversity. Several Prevotella spp. increased in relative abundance immediately after weaning as did butyrate-producing species such as Butyricicoccus porcorum, Faecalibacterium prausnitzii, and Megasphaera elsdenii. Within 7 days of weaning, the gut microbiome of pigs weaned at 21 and 28 days of age resembled that of pigs weaned at 14 d. Resistance genes to most antimicrobial classes decreased in relative abundance post-weaning with the exception of those conferring resistance to tetracyclines and macrolides-lincosamides-streptogramin B. The relative abundance of microbial carbohydrate-active enzymes (CAZymes) changed significantly in the post-weaning period with an enrichment of CAZymes involved in degradation of plant-derived polysaccharides. These results demonstrate that pigs tend to have a more similar microbiome as they age and that weaning age has only a temporary effect on the gut microbiome.

Risk for African Swine Fever Introduction Into Kazakhstan

African swine fever (ASF) is a disease of swine that is endemic to some African countries and that has rapidly spread since 2007 through many regions of Asia and Europe, becoming endemic in some areas of those continents. Since there is neither vaccine nor treatment for ASF, prevention is an important action to avoid the economic losses that this disease can impose on a country. Although the Republic of Kazakhstan has remained free from the disease, some of its neighbors have become ASF-infected, raising concerns about the potential introduction of the disease into the country. Here, we have identified clusters of districts in Kazakhstan at highest risk for ASF introduction. Questionnaires were administered, and districts were visited to collect and document, for the first time, at the district level, the distribution of swine operations and population in Kazakhstan. A snowball sampling approach was used to identify ASF experts worldwide, and a conjoint analysis model was used to elicit their opinion in relation to the extent at which relevant epidemiological factors influence the risk for ASF introduction into disease-free regions. The resulting model was validated using data from the Russian Federation and Mongolia. Finally, the validated model was used to rank and categorize Kazakhstani districts in terms of the risk for serving as the point of entry for ASF into the country, and clusters of districts at highest risk of introduction were identified using the normal model of the spatial scan statistic. Results here will help to allocate resources for surveillance and prevention activities aimed at early detecting a hypothetical ASF introduction into Kazakhstan, ultimately helping to protect the sanitary status of the country.

Preliminary Study Exploring Caretaker Perspectives of Euthanasia on Swine Operations

The purpose of this study was to gain a better understanding of euthanasia training, caretaker perceptions of euthanasia, and available resources for individuals who perform euthanasia as part of their job on swine operations in the United States. An online survey was distributed via an e-newsletter and in-person recruitment at swine industry events. Survey questions were related to training, attitudes towards performing euthanasia, work environment, and communication. Forty-five responses (17 workers, 21 managers, 7 owners) were recorded and summarized. The majority of workers (n = 14, 82%) agreed that they had “received enough training to euthanize pigs correctly” and that training had made them “confident about performing euthanasia”, yet 35% (6) also indicated they would like more euthanasia training. Less than one-third of workers indicated that strategies for dealing with “personal stress” (4, 24%) and “emotional wellness” 29% (5) were included in training programs but the majority (14, 82%) agreed that “trainings included human safety while performing euthanasia”. Most caretakers (37, 82%) agreed that they felt they could “communicate with my supervisors” if they felt uncomfortable performing euthanasia. Opportunities for the future include enhancing euthanasia training opportunities and content to include more awareness of strategies to deal with stress related to euthanasia.

PSV-19 Preliminary exploration of caretaker and manager perspectives of on-farm euthanasia on swine operations

Employees on swine operations have the critical role of ensuring animal health and well-being, which sometimes involves performing euthanasia. This study aimed to understand caretaker and manager involvement and perspectives on performing euthanasia on swine farms. Individuals were recruited through online (newsletters and emails to companies) and in-person (e.g. Pig Welfare Symposium, MN) methods in the fall of 2019. The survey consisted of 61 questions on topics related to training, methods of euthanasia, perspectives about euthanasia and knowledge of available mental health resources. Thirty-nine individuals participated in the survey (18 caretakers, 21 managers). Half of respondents (50%, n = 20) indicated that they were involved with making euthanasia decisions. The vast majority of respondents “believe that euthanasia is a humane way to end animal suffering” (95%; n = 36) and that “the euthanasia process on-farm is necessary” (97%; n = 34). A quarter of individuals (25%, n = 9) “feel emotionally upset after euthanizing a pig” and 84% (n = 26) indicated it is “easier to euthanize a pig the more they do it.” Additionally, 92% (n = 35) of respondents agreed that they have “enough experience and knowledge to know when to euthanize a pig.” Most of survey respondents (n = 34) agreed that they “feel as though I can communicate with my supervisors if I feel uncomfortable performing euthanasia” and that their “supervisors aim to promote a safe and encouraging work environment” (n = 38). Despite this, a small number of respondents (n = 6) did not feel “as though my supervisors acknowledge concerns that they may have” and did not feel that their supervisors take “an interest in my professional development and/or job performance.” Overall, data suggest that caretakers and managers understand the importance of euthanasia regarding animal well-being and generally feel they can communicate their concerns.

Organic dust induced mitochondrial dysfunction could be targeted via cGAS-STING or mitochondrial NOX-2 inhibition

ABSTRACTOrganic dust (OD) exposure in animal production industries poses serious respiratory and other health risks. OD consists of microbial products and particulate matter and OD exposure induced respiratory inflammation is under intense investigation. However, the effect of OD exposure on brain largely remains unknown. Recently, we have shown that OD exposure of brain microglial cells induces an inflammatory phenotype with the release of mitochondrial DNA (mt-DNA). Therefore, we tested a hypothesis that OD-exposure induced secreted mt-DNA signaling drives the inflammation. OD samples were collected from commercial swine operations and a filter sterilized OD extract (ODE) was prepared. Mouse (C57BL/6) microglial cell line was treated with medium or ODE (5%) for 48 hours along with either PBS or mitoapocynin (MA, 10 μM, NOX-2 inhibitor). Microglia treated with control or anti-STING siRNA were exposed to medium or ODE. Next, mouse (C57BL/6) pups were euthanized under an approved protocol, organotypic brain slice cultures (BSCs) were prepared and exposed to medium or ODE with or without MA treatment daily for five days. Culture supernatant, cell pellets and mt-free cytosolic fractions were processed to quantify mt-superoxide, mt-DNA, cytochrome C, TFAM, mitochondrial stress markers and mt-DNA induced signaling via cGAS-STING and TLR9. Data were analyzed using one-way ANOVA and post-hoc tests. A p value of ≤ 0.05 was considered significant. ODE exposure increased the mt-superoxide formation andMA treatment decreased the ODE-induced mt-DNA release into cytosol. ODE exposure increased the cytochrome C and TFAM levels. ODE increased MFN1/2 and PINK1 but not DRP1 and MA treatment decreased the MFN2 expression. MA treatment decreased the ODE-exposure induced mt-DNA signaling via cGAS-STING and TLR9. Anti-STING siRNA decreased the ODE-induced increase in IRF3, IFN-β and Iba1 expression. In BSCs, MA-treatment decreased the ODE induced TNF-α, IL-6 and MFN1. Taken together, OD exposure induced mt-DNA signaling could be curtailed through mitochondrial NOX-2 inhibition or STING suppression to reduce neuroinflammation.

Assessing Peak-To-Mean Ratios of Odour Intensity in the Atmosphere near Swine Operations

Odour in the atmosphere is usually characterized by an intermittent time series of high peaks and periods of low (or zero) concentrations. The peak-to-mean ratio (PMR) is commonly used to estimate short-term peaks from long-term averages to assess the odour impact. The objective of this study was to quantify the peak-to-mean ratio of odour intensity (PMR_OI) in the atmosphere near swine operations. Fifteen human assessors (sniffers) were trained to use an 8 point odour intensity scale to measure odour intensity in the ambient air near two swine operations. In each measurement session, the sniffers were placed 0° (in the direction of wind), 30°, and 45° from the wind directions at 100, 500, and 1000 m from the swine operations to sniff odour in the air every 10 s for 30 min. The results showed that odour in the atmosphere was intermittent. The intermittency (% of time when odour was detected) increased with the averaging time and decreased with the distance from the odour source and the direction from the wind. The measured intermittency ranged from 13% to 85%. The PMR_OI increased with the averaging time, the distance from the source, and the direction from the wind. In the wind direction, the largest difference in PMR_OI between 1 and 30 min averaging times was 68% (2.5 vs. 4.2), which occurred at 1000 m from the odour source under stability class B. The average PMR_OI increased from 1.5 at 100 m to 3.5 at 1000 m. Atmospheric stability had a noticeable effect on PMR_OI. At 1000 m, the 30 min PMR_OI decreased from 4.2 at stability class B (unstable) to 2.4 at E (slightly stable).

Principles and Clinical Uses of Real-Time Ultrasonography in Female Swine Reproduction

Within the past 30 years, through ongoing technology and portability developments, real-time (b-mode) ultrasonography (RTU) has increasingly become a valuable diagnostic tool in assessing the female reproductive tract in swine. Initially applied in swine production to visually determine pregnancy status, RTU use has expanded to include assessment of the peri-pubertal and mature non-pregnant females as well. Transabdominal and transrectal modalities to visualizing the reproductive tract in swine have been reported with the transabdominal approach more common due to the fact of its ease of accessibility, animal/personnel safety, and reduced time to perform. Adjustable frequency transducers are preferred as they allow optimization of image quality at various depths. If a single transducer frequency must be selected, a 5 MHz probe provides the best versatility for visualizing the reproductive tract in swine. Other basic requirements for ultrasound equipment which will be used on commercial swine farms include being light weight and easy to handle, readily cleanable and disinfectable, long battery-life, and good durability. When using RTU for pregnancy determination, diagnosis is based upon a combination of the animal’s breeding records, the presence of embryonic fluid, and, depending upon gestational stage, fetal structures. If RTU is used as a diagnostic tool in assessing reproductive problems in an individual or a group of animals, sonographic evaluation of both the uterus and ovaries is performed. Tissues are delineated and assessed based upon their echogenicity, echotexture, and size. Uses of RTU in clinical practice may include assessment of delayed puberty, prolonged wean-to-estrus interval, absence of post-weaning estrus, herd disruptions in conception and farrowing rates, vulval discharge, peripartum and puerperal disorders. This review aims to provide an overview on principles and clinical uses of RTU with respect to application to address female reproductive performance issues in commercial swine operations.