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Introduction: Sow mortality in the U.S. swine industry has increased in recent years, for which pelvic organ prolapse (POP) is a major contributor, accounting for 21% of all sow mortality. Dysbiosis of microbial communities has been associated with disease and reproductive dysfunction in several species, and previous studies have shown changes in vaginal microbiota in sows with increased risk for POP during late gestation. However, there is insufficient knowledge surrounding the potential relationship between fecal microbiota and POP in sows. Therefore, the study objective was to identify differences in sow fecal microbiota and determine if fecal and vaginal microbial communities are correlated in relation to POP risk. Methods: Sows were evaluated for POP risk using an established perineal scoring system, with a perineal score (PS) of 1 (PS1) presuming little to no risk of POP to a PS of 3 (PS3) presuming high risk of POP. In the current study, 2,864 sows were scored during gestation week 15, and 1.0%, 2.7%, and 23.4% of PS1, PS2, and PS3 sows, respectively, subsequently experienced POP. Fecal swabs (n = 215) were collected between gestation days 108-115, DNA was extracted, and 16S rRNA gene amplicon sequencing libraries were analyzed using mothur, phyloseq and SAS in reference to PS and POP outcome. Additionally, co-occurrence networks were constructed using CoNet to compare fecal and vaginal microbiota from the same cohort of sows and identify correlations between different taxa. Results: Differences in fecal community composition (PERMANOVA; P < 0.05), structure (alpha diversity measurements; P < 0.05), and 13 individual operational taxonomic units (OTUs) were revealed between PS1 and PS3 assigned sows. No differences in fecal microbiota were detected as a result of POP outcome. However, the abundances of several taxa were correlated across sample collection sites, suggesting the fecal and vaginal microbial communities may be related to one another. Discussion: Collectively, fewer differences in the fecal microbiota exist in sows with differing risk for POP compared to the vaginal microbiota, suggesting the vaginal microbiome may be more relevant in relation to POP outcome, although correlations between fecal and vaginal communities may provide insight for strategies to combat POP. [ABSTRACT FROM AUTHOR]

The swine industry is comprised of highly productive and healthy sows capable of weaning large litters for multiple parities. This prolificacy has resulted in greater metabolic demands during lactation due to increased capacity and demand for milk production. Modern sows also have increased genetic merit for leanness which has altered the amount of energy reserves available for mobilization to support the growing demands of lactation. Together, these factors may render modern sows more vulnerable to metabolic disorders such as postpartum dysgalactia syndrome (PDS) or mastitis-metritis-agalactia (MMA). Described as a metabolic and hormonal disturbance, a hallmark of PDS is a reduction (dysgalactia) or cessation (agalactia) in milk production after farrowing. Insufficient milk production by the sow leads to increased piglet mortality, causing substantial economic losses, reducing sow welfare, and resulting in premature removal of sows from the herd. Our prior reports have shown differences in circulating analytes and inflammatory markers between healthy sows and sows affected with PDS following parturition. However, very few differences were observed before clinical signs were evident, rendering these analytes ineffective in early detection of PDS. Therefore, the objective of the current study was to utilize gas-chromatography mass-spectrometry (GC-MS) to further characterize the biological conditions and metabolic pathways contributing to PDS in sows. Through this, we aimed to identify small molecules in circulation with the potential for use as a biomarker to aid in early detection of PDS. To accomplish this, a study was conducted on a commercial sow farm with a history of poor lactation performance. Sows (n = 36) with clinical signs of PDS were matched by parity and day of lactation with healthy control (CON) sows (n = 36) that remained unaffected. Blood samples collected at farrowing (timepoint 1) and at onset of clinical PDS (timepoint 2) were subjected to GC-MS. As expected, piglets from PDS sows had decreased (P < 0.01) average daily gain and greater mortality than piglets from control sows. Following GC-MS analysis, 16 and 41 molecules were identified as significantly different between CON and PDS sows at timepoint 1 and timepoint 2, respectively (P < 0.10). A difference in 2-hydroxybutyric acid, an early marker for insulin resistance and impaired glucose regulation, was observed at timepoint 1. Additional molecules identified as significantly different at timepoint 1 include D-pinitol, D-glucose, inositol (3,6)-bisphosphate, and others. These differentially abundant molecules at timepoint 1 represent potential biomarkers for early detection of PDS. [ABSTRACT FROM AUTHOR]

Within the last decade, increased sow mortality resulting from pelvic organ prolapse (POP) has become a growing concern in the swine industry. Despite being widely acknowledged as a prevailing sow welfare and production issue, mitigation strategies are lacking. Previous studies have demonstrated changes in the vaginal microbiome are associated with increased risk for POP during late gestation. Therefore, the vaginal microbiome represents a potential target for prevention strategies. The objective of the current study was to evaluate effects of vaginal infusion using ampicillin on POP incidence. We hypothesized that altering the vaginal microbiome through the use of antibiotics would reduce POP risk during late gestation. Ampicillin was infused into the vagina at two timepoints during late gestation. The first dose (10 mL at 200 mg/mL) was administered approximately three weeks prior to farrowing followed by a second, equivalent dose at approximately three days pre-farrowing. Sows were randomly assigned to treated (TRT; n = 824) and non-treated (CON; n = 739) groups based on gestation pen. Eighty-seven percent of sows in the TRT group received both infusions of ampicillin. At gestation week 15, sows (n = 1076) were evaluated for prolapse risk using a 3-point perineal scoring system. Briefly, a perineal score (PS) of 1 (PS1) presumes little to no risk of prolapse, a PS of 2 (PS2) presumes moderate risk of POP, and a PS of 3 (PS3) presumes high risk of prolapse. From the 1,076 sows assigned a PS, 46.5%, 49.7% and 3.8% of sows were scored PS1, PS2, or PS3, respectively. Ampicillin treatment did not affect PS (P = 0.20) during late gestation, with 45.6%, 51.6% and 2.8% of CON sows and 47.2%, 48.1% and 4.7% of TRT sows scoring a PS1, PS2, or PS3, respectively. Additionally, treatment did not affect POP incidence (P = 0.74), with 4.5% of CON sows and 4.7% of TRT sows subsequently experiencing POP. When evaluating litter characteristics, ampicillin treatment did not affect number of total born, liveborn, or stillborn piglets (P = 0.54). However, an effect of PS was observed on total born and stillborn piglets (P ≤ 0.01), and a tendency to effect number of liveborn piglets (P = 0.06). Sows assigned a PS3 during late gestation had fewer piglets born alive, presumably due to the increased number of stillborn piglets. Additionally, PS3 sows had 1 more total piglet on average within their litters compared with PS1 assigned sows (P = 0.01). In conclusion, vaginal infusion of ampicillin had no effect on PS, POP incidence or litter characteristics, but PS did have an effect on the number of piglets born alive. This project was supported by the National Pork Board and the Foundation for Food and Agriculture Research. [ABSTRACT FROM AUTHOR]

In the U.S. swine industry, feeding programs are focused on using feed ingredients that are easily digestible and cost effective. With the predicted increases in soybean processing, pig producers may have increased availability of a cost-effective protein source in soybean meal (SBM). This expanded availability of SBM may result in feeding protein above the ostensible requirements, which would likely intensify the thermic effect of digestion, potentially increasing the susceptibility of the pig to heat stress (HS). Heat stress has damaging effects on feed intake and growth performance, costing the swine industry >$900 million annually. Therefore, the study objectives were to evaluate the effects of dietary crude protein diets (in the form of SBM) during HS on growth performance in growing pigs. Growing pigs (n = 40; initial BW = 55 ± 5.6 kg) were allocated into six treatments: 1) thermoneutral (TN) ad libitum control diet (TN-Ctl; n = 6), 2) TN pair-fed (PF) control diet (PF-Ctl; n = 6), 3) HS ad libitum control diet (HS-Ctl; n = 8), 4) TN ad libitum high SBM diet (TN-SBM; n = 6), 5) TN PF high SBM diet (PF-SBM; n = 6), and 6) HS ad libitum high SBM diet (HS-SBM; n = 8). The control diet included 15% crude protein (CP) while the high SBM diet included 23% CP with excess amino acids. The study consisted of two periods: Period 1 (P1; 7 d) in which all pigs were housed in TN environments (26.7 ± 1.4°C) with ad libitum access to respective diets. Period 2 (P2; 21 d), HS groups were exposed to cyclical HS with daytime temperatures reaching 35°C and evening temperatures decreased to 29.4°C. During P2, PF groups were fed to respective HS-Ctl or HS-SBM equivalents in TN conditions. Pigs exposed to HS had an overall increase in rectal temperature and respiration rate (0.91°C and 45 bpm, respectively; P ≤ 0.01) and HS-SBM pigs had increased evening rectal temperature (± 0.13°C; P ≤ 0.01), relative to HS-Ctrl. Overall, HS decreased ADFI (19%; P ≤ 0.01), ADG (26%; P ≤ 0.01) and increased F:G (10%; P ≤ 0.01) irrespective of dietary CP levels. Loin muscle area (P = 0.19) and backfat (P = 0.98) were not different between the TN and HS pigs regardless of diet. Circulating blood urea nitrogen levels did not differ between HS and TN pigs (P = 0.68), but an increase was observed in pigs fed the SBM diet relative to the control diet (P ≤ 0.01). In summary, these results demonstrate that HS decreases growth performance, but the negative effects are not augmented by feeding a high SBM diet. [ABSTRACT FROM AUTHOR]

Seasonal infertility (SI) caused by heat stress (HS) impacts the US swine industry by reducing litter size, farrowing rates, and production efficiency. Identifying the biological underpinnings of SI is a foundational step towards developing mitigation strategies to reduce the nearly $1 billion annual revenue losses to the swine industry. The study objective was to investigate the direct and indirect effects of HS via HS conditioned serum infusion in swine. We hypothesized gilts housed in thermoneutral (TN) conditions receiving gradual infusions of serum obtained from HS gilts would experience altered endocrine and metabolic function compared to gilts receiving serum from TN gilts. Prepubertal gilts (n = 18) were assigned to donor or recipient groups and donors were allocated to TN or HS environments. Blood was collected from HS donors and TN donors exposed to 24-hours of HS or TN conditions, respectively. Serum was infused into recipients housed in TN conditions via indwelling jugular catheters. Over a 24-hour period approximately 20% of the estimated recipient gilt serum volume from donors (pooled by treatment) was infused into recipients. After infusions were completed, gilts were euthanized and tissues collected. Increased rectal temperatures were observed in HS recipients compared to TN recipients (P ≤ 0.05). Protein extracts from liver and ovary underwent proteomic analysis via liquid-chromatography with tandem mass-spectrometry (LC-MS/MS) to assess protein abundance. In the liver and ovary, we identified 135 and 264 proteins, respectively, that were differentially abundant between TN and HS recipients (P < 0.10). Gene Ontology enrichment analysis identified alterations to pathways involved in hormone regulation, immune response, and apoptosis. Collectively, these data demonstrate gilts receiving HS serum experienced altered endocrine and metabolic function compared to gilts receiving TN serum. This project was supported in part by the Iowa Pork Producers Association. USDA is an equal opportunity provider and employer. [ABSTRACT FROM AUTHOR]

Functional corpora lutea (CL) are required for pregnancy establishment and gestational maintenance in swine. Manganese (Mn) could be critical in regulating CL function since it is a cofactor for the enzyme Mn superoxide dismutase (Mn-SOD) as well as enzymes involved in progesterone (P4) synthesis. We hypothesized a more bioavailable dietary Mn source would increase CL Mn content thereby influencing luteal function during the mid-luteal phase of the estrous cycle. Post-pubertal gilts (n = 32) were assigned to one of four gestation diets. The control diet (CON) met or exceeded NRC requirements and was formulated to contain 20 ppm added Mn in the form of Mn sulfate. Three additional diets included 20 (TRT1), 40 (TRT2) or 60 (TRT3) ppm Mn from a Mn-amino acid complex (Availa-Mn; Zinpro Corporation) in place of Mn sulfate. Dietary treatment began at estrus synchronization onset and continued through D12 of the ensuing estrous cycle when gilts were euthanized. Mn content increased (P = 0.06) 19, 21 and 24% in CLs of gilts fed TRT1, TRT2, and TRT3, respectively, and luteal P4 concentration decreased (P = 0.03) 25, 26, and 32% in gilts fed TRT1, TRT2, and TRT3, respectively, compared to CON. Total CL protein was extracted and liquid chromatography with tandem mass spectrometry (LC-MS/MS) was performed to assess global protein abundance. Compared to CON, 29, 105, and 118 proteins were differentially abundant (P < 0.01) in TRT1, TRT2, and TRT3, respectively. KEGG pathway analysis revealed proteins involved in P4 signaling (membrane-associated P4 receptor component 2) and cholesterol synthesis and transport (mevalonate kinase, diphosphomevalonate decarboxylase, low density lipoprotein receptor) were downregulated in response to Availa-Mn. Collectively, these data support the posit that dietary Mn source affects Mn accumulation and P4 concentration in CL tissue and influences protein abundance which may affect CL function. [ABSTRACT FROM AUTHOR]

Sow mortality, as the result of pelvic organ prolapse (POP), has increased during recent years in the U.S. swine industry and continues to worsen. The objective of this study was to identify putative biological factors associated with POP risk. We hypothesized sows differing in POP risk would differ in serum factors and steroid hormone profiles. Perineal scores (PS) were assigned to sows (n=2865) during late gestation (days 107-116) to assess POP risk. Sows assigned a PS1 had a presumed low risk of POP while those assigned a PS2 or PS3 had a presumed moderate or high risk of POP, respectively. Subsequently, 1.0, 2.7, and 23.4% of sows scored as PS1, PS2, or PS3, experienced POP, respectively. Blood samples were collected on a subset of sows (n=215) identified as PS3 along with paritymatched PS1 sows at the time of scoring and whole blood was subjected to complete blood count (CBC) analysis. Serum from a subset of these (n=110) samples were also subjected to a 17-panel hormone analysis. Additionally, serum biomarkers of inflammation, C-reactive protein and haptoglobin, were analyzed in PS3 sows that subsequently experienced POP and parity matched PS1 sows that did not experience POP. The CBC analysis revealed a 4.3, 7.8 and 5.9% decrease (P < 0.05) in mean platelet volume, lymphocytes, and monocytes, respectively, in PS3 compared to PS1 sows. Deoxycortisol, androstenedione, androsterone, estrone, β-estradiol, and testosterone were greater (P < 0.05) in PS3 compared to PS1 sows. Circulating haptoglobin was unaffected (P = 0.35) by PS, although C-reactive protein was 24.6% greater (P = 0.02) in PS3 sows. Collectively, serum differences in hormone profiles and biomarkers consistent with inflammation in sows differing in POP risk. This project was supported by the National Pork Board and the Foundation for Food and Agriculture Research. [ABSTRACT FROM AUTHOR]