Control Piglets Research Articles

PSI-24 Acute and chronic stress response following weaning and transportation in the average piglet

Abstract The American swine industry relies on a model where facilities for farrowing are often geographically isolated from those used later for wean-finish, which necessitates multiple coincident stressors including weaning, mixing, transportation and feed/water restriction. Previous studies indicate this combined stress reduces subsequent growth performance; however, the specific impact of each stressor on an average, objectively healthy piglet is not well understood, nor is the acute physiological response to this life event. The objective of this study was to determine the effect these stressors on thyroid function, intestinal health, and body weight (BW) in average, healthy pigs. In this study, a total population of 588 piglets were weighed the day prior to weaning and 230 piglets with the lowest Z-scores for BW were selected (5.74 ± 0.70 kg). Piglets (n = 70) were weaned directly into nursery pens and provided with feed and water, 70 were transported for 10 h with no access to feed and water, and 70 were grouped together into 2 large pens with no access to feed and water for an equivalent 8 h period. The remaining 20 piglets were not weaned and served as an unstressed control group. A total of 10 pigs from each group were euthanized at 32 and 56 h post-weaning for tissue sampling. Ileal villi height, crypt depth, and goblet cell numbers were measured, and no treatment effects observed (P > 0.05). Serum triiodothyronine (T3) concentrations were measured pre-treatment (t = 0), 24 h (t = 24), 48 h (t = 48), and immediately following euthanasia (t = 32 or 56 d). There were no significant differences in serum T3 among treatments at t = 0. At all-time points post stress event, control piglets had greater T3 concentrations compared with feed restricted (P < 0.05) and transported (P < 0.05) pigs. Weaned pigs at t = 32, t = 48, and t = 56 had decreased T3 concentrations (P < 0.05) and weaned pigs tended (P = 0.0584) to have decreased t = 24 T3 concentrations compared with pigs remaining with the sow. The remaining pigs (n = 50) per weaning group were weighed weekly throughout the nursery phase and every 3 wk in the grow-finish phase to determine the impact of each stressor on growth. There was no significant effect of weaning treatment on BW at any time point (P > 0.10). Carcass data including carcass weight, loin and backfat depths, and lean percentage were measured at time of slaughter with no significant differences found among groups (P > 0.60). As no effect on growth weight or carcass characteristics were observed between treatment groups in average pigs, this suggests that it may be beneficial to transport average pigs the longest distance, while minimizing transport for pigs on either end of the weaning weight spectrum. Further research is needed to compare effects of weaning and transportation stressors on average and weight extremes of weaned pigs.

Indole-3-propionic acid enhances growth performance and reduces diarrhea via modulating redox status and intestinal inflammation in weaned piglets

Indole-3-propionic acid (IPA) has anti-inflammatory properties, which can be beneficial for weaned piglets with underdeveloped immune systems. The study explores the impact of IPA supplementation on growth performance, oxidative stress, and inflammation response in weaned piglets. In experiment (Exp.) 1, ninety weaned piglets were divided into six groups (five replicates per group, three pigs per replicate), with each group receiving a basal diet with varying amounts of IPA (0, 50, 100, 200, 400, or 600 mg/kg) for 42 d. Piglets fed the diets with 50, 100, and 200 mg/kg of IPA exhibited reduced feed conversion ratios (F: G) compared to the control piglets (P = 0.035). Notably, 50 and 100 mg/kg IPA treatments significantly reduced diarrhea incidence and serum interleukin (IL)-6 content (P < 0.05). Conversely, a high dosage of 600 mg/kg IPA led to increased serum contents of tumor necrosis factor (TNF)-α, and IL-6 (P < 0.05). Optimal antioxidant benefits were observed at 100 mg/kg IPA supplementation, which significantly reduced malondialdehyde levels while enhancing serum total antioxidant capacity and total superoxide dismutase activity on d 14 (P < 0.05). Exp. 2 investigated the effects of IPA on lipopolysaccharide (LPS) challenge in weaned piglets. The study consisted of 32 weaned piglets allocated into 4 groups, with 8 replicates per group and 1 piglet per replicate: a control group, a LPS challenge group, a LPS challenge group supplemented with 100 mg/kg IPA, and a group supplemented with 100 mg/kg IPA alone. Upon administration of LPS or saline injection, the results indicated that dietary IPA supplementation in challenged piglets enhanced villus height: crypt depth, modulated IL-8 and IL-22 mRNA relative expression, and increased the tight junction protein claudin-1 mRNA relative expression in the intestinal mucosa (P < 0.05). These findings suggest that dietary supplementation of IPA at specific concentrations significantly improves growth performance, reduces diarrhea incidence, and mitigates inflammation and oxidative stress in weaned piglets. It may be concluded that incorporating IPA into the diet of weaned piglets can effectively improve their health and development.

Impact of adding eicosapentaenoic and docosahexaenoic acid-rich fish oil in sow and piglet diets on blood oxylipins and immune indicators of weaned piglets

Weaning is a decisive event in piglets’ life. This study aimed to evaluate whether the inclusion of fish oil, rich in eicosapentaenoic and docosahexaenoic acids (EPA and DHA), in sow and piglet diets, increased the concentration of anti-inflammatory molecules in the blood of weaned piglets and whether the effect was dependent on the pigs being born with either low or a high birth BW (bBW). Thirty-six sows in four consecutive batches were randomly distributed between a control diet with animal fat (15 g/kg in gestation and 30 g/kg in lactation) or a n-3 long-chain fatty acid diet (LCFA; totally or half replacing animal fat by fish oil during gestation and lactation, respectively) from service until weaning (ca. 28 days). At birth, the two lightest (LBW) and the two heaviest (HBW) piglets in each litter were identified and, at weaning, grouped in pens by pairs prioritising their bBW. Pens were further distributed into a control (30 g/kg animal fat) or n-3 LCFA diet (totally replacing animal fat by fish oil) for 28 days. At the end of the trial, blood was collected from piglets in the first batch (n = 48). Serum fatty acids (FAs) were quantified by GC, plasma oxylipins by ultra-HPLC-MS, and plasma immune indicators by ELISA. An interaction between piglet diet and bBW for average daily gain (P = 0.020) and average daily feed intake (P = 0.014) during the whole postweaning indicated that dietary n-3 LCFA−promoted LBW piglets to have a similar growth and intake than HBW piglets reaching 1.5 kg average BW more at the end of the postweaning period than LBW control piglets. Fish oil in piglet diets also increased the concentrations of total n-3 FA, EPA and DHA (all P < 0.001), their resultant oxylipins, particularly their hydroxy derivatives from lipoxygenase enzymatic pathway (all P < 0.001) and tended to increase immunoglobulin M (P = 0.067) in blood. Regarding the bBW category, LBW piglets tend to increase tumour necrosis factor α in plasma (P = 0.083) compared to HBW. It is concluded that fish oil in postweaning diets could enhance the daily gain and feed intake of LBW piglets, increasing the concentration of serum n-3 FAs and their derived oxylipins in plasma.

Cascading renal injury after brain death: Unveiling glycocalyx alteration and the potential protective role of tacrolimus.

Brain death (BD) is a complex medical state that triggers systemic disturbances and a cascade of pathophysiological processes. This condition significantly impairs both kidney function and structural integrity, thereby presenting considerable challenges to graft viability and the long-term success of transplantation endeavors. Tacrolimus (FK506), an immunosuppressive drug, was used in this study to assess its impact as a pretreatment on brain death-induced renal injury. This study aimed to investigate changes associated with brain death-induced renal injury in a 4-month-old female porcine model. The experimental groups included brain death placebo-pretreated (BD; n = 9), brain death tacrolimus-pretreated using the clinical dose of 0.25mg/kg the day before surgery, followed by 0.05mg/kg/day 1hour before the procedure (BD + FK506; n = 8), and control (ctrl, n = 7) piglets, which did not undergo brain death induction. Furthermore, we aimed to assess the effect of FK506 on these renal alterations through graft preconditioning. We hypothesized that immunosuppressive properties of FK506 reduce tissue inflammation and preserve the glycocalyx. Our findings revealed a series of interconnected events triggered by BD, leading to a deterioration of renal function and increased proteinuria, increased apoptosis in the vessels, glomeruli and tubules, significant leukocyte infiltration into renal tissue, and degradation of the glycocalyx in comparison with ctrl group. Importantly, treatment with FK506 demonstrated significant efficacy in attenuating these adverse effects. FK506 helped reduce apoptosis, maintain glycocalyx integrity, regulate neutrophil infiltration, and mitigate renal injury following BD. This study offers new insights into the pathophysiology of BD-induced renal injury, emphasizing the potential of FK506 pretreatment as a promising therapeutic intervention for organ preservation, through maintaining endothelial function with the additional benefit of limiting the risk of rejection.

ЦИРКОВИРУС-МИКОПЛАЗМЕННАЯ ИНФЕКЦИЯ ПОРОСЯТ В ЭКСПЕРИМЕНТЕ

The aim of the study is to investigate the manifestation of circovirus-mycoplasma infection in piglets both as a mixed infection and as a monoinfection in the experiment. Objectives: to study the interaction of circovirus type 2 with Mycoplasma hyopneumoniae in the body of weaned piglets, as well as the manifestation of monoinfection in piglets during experimental infection; to assess the pathogenicity of PCV2d/M.hyo mixed infection, PCV2d monoinfection and M. hyo monoinfection; to identify the clinical and pathomorphological manifestation of mixed and single circovirus and mycoplasma infection in the experiment. Four groups of 23-day-old piglets (5 heads each) were formed and tested for the absence of pathogens. Experimental group I – mixed circovirus-mycoplasma infection, experimental group II – PCV2d monoinfection, experimental group III – M.hyo monoinfection, group IV – control. After infection, rectal temperature was measured daily and clinical manifestations were observed, nasal swabs were taken to determine the number of copies of M. hyo nucleic acid, blood was taken from each piglet weekly to detect viral nucleic acid and antibodies. All experimental and control piglets were euthanized on the 35th day from the beginning of the experiment. Pathomorphological and pathohistological studies were carried out. The experimental study reveals the synergistic pathogenicity of PCV2d and M. hyo in mixed infection. In experimental infection of weaning piglets with both M. hyo monoinfection and M. hyo/PCV2d mixed infection, it was found that M. hyo nucleic acid was detected in nasal smears in 80 % of animals and in lung tissue in 100 %. The number of copies of the PCV2d circovirus genome in the inguinal lymph node tissue of piglets in the mixed infection group was higher than in the monoinfection group. Circovirus type 2 in piglets can proceed latently, and circovirus-mycoplasma infection can be a complex respiratory disease.

Brief apnea with hypoventilation reduces seizure duration and shifts seizure location for several hours in a model of severe traumatic brain injury.

Seizures can be difficult to control in infants and toddlers. Seizures with periods of apnea and hypoventilation are common following severe traumatic brain injury (TBI). We previously observed that brief apnea with hypoventilation (A&H) in our severe TBI model acutely interrupted seizures. The current study is designed to determine the effect of A&H on subsequent seizures and whether A&H has potential therapeutic implications. Piglets (1 week or 1 month old) received multifactorial injuries: cortical impact, mass effect, subdural hematoma, subarachnoid hemorrhage, and seizures induced with kainic acid. A&H (1 min apnea, 10 min hypoventilation) was induced either before or after seizure induction, or control piglets received subdural/subarachnoid hematoma and seizure without A&H. In an intensive care unit, piglets were sedated, intubated, and mechanically ventilated, and epidural electroencephalogram was recorded for an average of 18 h after seizure induction. In our severe TBI model, A&H after seizure reduced ipsilateral seizure burden by 80% compared to the same injuries without A&H. In the A&H before seizure induction group, more piglets had exclusively contralateral seizures, although most piglets in all groups had seizures that shifted location throughout the several hours of seizure. After 8-10 h, seizures transitioned to interictal epileptiform discharges regardless of A&H or timing of A&H. Even brief A&H may alter traumatic seizures. In our preclinical model, we will address the possibility of hypercapnia with normoxia, with controlled intracranial pressure, as a therapeutic option for children with status epilepticus after hemorrhagic TBI.

PSIV-14 Assessing sow and suckling pig hemoglobin status in a single lactation following one or two iron supplementations of piglets in a commercial farm

Abstract Newborn piglets are typically anemic at birth [defined as blood hemoglobin concentration (Hb) &amp;lt; 10 g/dL] and sow’s milk contains negligible amounts of iron; common commercial practice is one dose of injectable iron in the first week of life. However, a considerable proportion of piglets have decreased Hb at weaning which may have implications on post-wean performance. Thus, there is interest in additional iron supplementation before weaning. The primary objective of this study was to evaluate the impact of one or two iron supplementations on offspring performance. A total of 172 sows (parity 1 to 8) and litters (n = 2,378 piglets) were assigned in a randomized complete block design to Control [piglets received one injectable iron dose (400 mg)], SUPoral (injectable iron as Control plus oral iron supplement at 1oz/litter per day for 8 d before weaning), or SUPinject (injectable iron as Control plus 100 mg 7 d before weaning). According to barn stand protocol, the first iron dose was provided to all piglets on d 7 after the initiation of farrowing. Sow Hb status was determined at entry to farrowing house and weaning; -Hb status of all born alive piglets was measured within 28 of birth and at weaning. Analysis of variance compared the effect of iron supplementation, parity, and their interaction on piglet Hb status. Sow Hb at entry (9.3, 10.4, and 9.6 g/dL ± 0.15, respectively) was less (P &amp;lt; 0.001) for parity 4-8 sows than parity 1, with parity 2-3 intermediate and no difference between parity groups at weaning (9.5 g/dL ± 0.16). Litter size at birth (total or born alive) and preweaning mortality did not differ between treatments. Piglet Hb at birth was not different between treatments; however, 85% of piglets from parity 4-8 sows were deemed anemic at birth compared with 72 and 76% in parity 1 and 2-3 sows, respectively (P &amp;lt; 0.05). Immediately before additional iron supplementation, Control piglets had lower (P &amp;lt; 0.0001) Hb than SUPoral and SUPinject piglets (7.4 vs 8.0 and 8.1 g/dL ± 0.12, respectively). At weaning, there were no differences in piglet Hb by iron supplementation treatments (11.4 g/dL ± 0.07). However, the percentage of piglets within a litter deemed anemic at weaning was greater (30%; P &amp;lt; 0.011) in parity 4-8 sows compared with parity 1 sows at 13%. There was no difference in piglet body weight at weaning between treatment groups or by parity grouping. In this study, additional iron supplementation before weaning had minimal impact on piglet iron status or growth. The decreased Hb at entry in older sows combined with greater proportion of anemic piglets at birth or weaning suggests greater attention to sow iron intake may be warranted.

PSV-17 Glycerol monolaurate improves litter performance and modifies milk composition when fed to lactating sows

Abstract Glycerol monolaurate (GML) has proven antibacterial, antiviral and anti-inflammatory properties, and additionally has been shown to increase milk immunoglobulins and improve gut health. However, limited information is available on how feeding GML to the sow prior and during lactation can influence the performance of the nursing pig. The objective of this study was to determine if feeding GML to sows would help maintain body condition, increase lauric acid in milk and improve litter performance. A total of 50 sows were randomly assigned to either a control feed or to a control feed with 1.5 kgs/mT of GML (LipoVital GL-90) 3 to 5 dbefore farrowing. Sow and litter performance was measured until weaning at 25 d. On d 1, piglets were cross-fostered within treatment and weighed. Creep feed was offered. Milk samples were taken from 5 randomly selected sows per treatment on d 3 and 25. Glycerol monolaurate had no effect on number of pigs born alive, born dead, stillborn, or number weaned (P &amp;gt; 0.20). No treatment differences (P &amp;gt; 0.20) were observed for sow feed intake, loss of backfat thickness or body weight losses during the study. Control piglets tended to consume more creep feed than GML piglets (P &amp;lt; 0.15). Starting body weight was less for GML piglets (P &amp;lt; 0.001). Despite the decreased starting body weight, weaning weight was not different between treatments (P &amp;gt; 0.20). Using starting body weight as a covariate, total body weight gain tended to be greater (P &amp;lt; 0.08) for GML piglets than the control piglets (5.01 kgs vs 4.89 kg, respectively). Glycerol monolaurate-fed pigs in the bottom quartile of starting body weights (&amp;lt; 1.3 kgs) numerically out gained their control counterparts (4.67 kgs vs 4.12 kgs). Milk from GML sows had 57% more lauric acid on d 3 (P &amp;lt; 0.05) and 124% more lauric acid at weaning compared with control sows (P &amp;lt; 0.05). In conclusion, GML maintained sow body condition, increased the content of lauric acid in milk and improved piglet body weight gain, especially in lighter body weight piglets. The results from this study demonstrate the application of GML in commercial sow herds will be beneficial to both sow and litter.

PSIII-10 Impact of late gestation vitamin A and D injection on offspring growth and immune parameters in piglets

Abstract Supranutritional use of vitamins may have an impact on mortality rates of sows and piglets. Specifically, injection of vitamin A, and vitamin A and D (VitAD) has improved subsequent preweaning mortality when given to sows after weaning and improved immune response in offspring when administered to cattle in late gestation. However, little work has been conducted to investigate developmental impacts of gestational vitamin supplementation in piglets that may impact immune development. To investigate the relationship of VitAD supplementation on offspring development, this study evaluated sows (n = 20) injected intramuscularly with VitAD (312,000 IU vitamin A, 52,500 IU vitamin D) or a saline at d 85 of gestation. Effect of VitAD on performance and immune development was assessed from birth through wk 5 post weaning. Starting at birth (n = 95 VitAD, n = 114 control) piglet serum was collected weekly during the 4 wk lactation period, and a subset of piglets were bled weekly through the nursery. Blood was analyzed for retinol concentrations from birth through 5 wk post weaning and immune parameters via complete blood count analysis for 5 wk post weaning. Milk samples were also collected weekly during lactation and assessed for retinol concentrations via liquid chromatography. Data were assessed via a mixed procedure (SAS 9.4) with sow as random and treatment as fixed variables. Covariate of wean age was assessed for post weaning growth and of sampling time for retinol and CBC analysis. At farrowing, differences in birth weights were not observed (P ≥ 0.69). Through the lactation phase, control piglets had a tendency for increased average daily gain (P ≥ 0.07); however, no differences (P ≥ 0.27) were observed in piglet growth performance during the nursery phase. Blood and immune parameters assessed were not different across treatments from birth through 9 wk of age. Circulating retinol concentrations were greater in the control group, (P ≤ 0.05) at 15, 22, and 28 d of age, compared with VitAD. Milk retinol concentrations were increased in the VitAD group on d 8 of life, (P ≤ 0.05), but not at any other time during lactation. These results suggest that supplementation of VitAD on d 85 of gestation in sows impacts the retinol concentrations in milk for a limited period, but not growth or circulating retinol and immune parameters in piglets at any age. Based on these data, efficacy of supranutritional injection of VitAD may be timing specific and limited to benefiting the litter during lactation. Further research is needed to assess specificity of timing and impacts on piglet health and survival.

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.

Transthoracic echocardiography is a simple tool for size matching in cardiac xenotransplantation.

Preoperative size matching is essential for both allogeneic and xenogeneic heart transplantation. In preclinical pig-to-baboon xenotransplantation experiments, porcine donor organs are usually matched to recipients by using indirect parameters, such as age and total body weight. For clinical use of xenotransplantation, a more precise method of size measurement would be desirable to guarantee a "perfect match." Here, we investigated the use of transthoracic echocardiography (TTE) and described a new method to estimate organ size prior to xenotransplantation. Hearts from n = 17 genetically modified piglets were analyzed by TTE and total heart weight (THW) was measured prior to xenotransplantation into baboons between March 2018 and April 2022. Left ventricular (LV) mass was calculated according to the previously published method by Devereux etal. and a newly adapted formula. Hearts from n = 5 sibling piglets served as controls for the determination of relative LV and right ventricular (RV) mass. After explantation, THW and LV and RV mass were measured. THW correlated significantly with donor age and total body weight. The strongest correlation was found between THW and LV mass calculated by TTE. Compared to necropsy data of the control piglets, the Devereux formula underestimated both absolute and relative LV mass, whereas the adapted formula yielded better results. Combining the adapted formula and the relative LV mass data, THW can be predicted with TTE. We demonstrate reliable LV mass estimation by TTE for size matching prior to xenotransplantation. An adapted formula provides more accurate results of LV mass estimation than the generally used Devereux formula in the xenotransplantation setting. TTE measurement of LV mass is superior for the prediction of porcine heart sizes compared to conventional parameters such as age and total body weight.

Enteral plasma supports brain repair in newborn pigs after birth asphyxia

Newborns exposed to birth asphyxia transiently experience deficient blood flow and a lack of oxygen, potentially inducing hypoxic-ischaemic encephalopathy and subsequent neurological damage. Immunomodulatory components in plasma may dampen these responses. Using caesarean-delivered pigs as a model, we hypothesized that dietary plasma supplementation improves brain outcomes in pigs exposed to birth asphyxia. Mild birth asphyxia was induced by temporary occlusion of the umbilical cord prior to caesarean delivery. Motor development was assessed in asphyxiated (ASP) and control (CON) piglets using neonatal arousal, physical activity and gait test parameters before euthanasia on Day 4. The ASP pigs exhibited increased plasma lactate at birth, deficient motor skills and increased glial fibrillary acidic protein levels in CSF and astrogliosis in the putamen. The expression of genes related to oxidative stress, inflammation and synaptic functions was transiently altered in the motor cortex and caudate nucleus. The number of apoptotic cells among CTIP2-positive neurons in the motor cortex and striatal medium spiny neurons was increased, and maturation of preoligodendrocytes in the internal capsule was delayed. Plasma supplementation improved gait performance in the beam test, attenuated neuronal apoptosis and affected gene expression related to neuroinflammation, neurotransmission and antioxidants (motor cortex, caudate). We present a new clinically relevant animal model of moderate birth asphyxia inducing structural and functional brain damage. The components in plasma that support brain repair remain to be identified but may represent a therapeutic potential for infants and animals after birth asphyxia.

Dose-Dependent Effects of Supplementing a Two-Strain Bacillus subtilis Probiotic on Growth Performance, Blood Parameters, Fecal Metabolites, and Microbiome in Nursery Pigs.

This experiment was conducted to evaluate the effects of dietary supplementation level of a two-strain Bacillus subtilis probiotic on growth performance, blood parameters, fecal metabolites, and microbiome in nursery pigs. A total of 54 weaned piglets were allotted to three treatments in three replicate pens with six pigs/pen for a 28 d feeding trial. The treatments were as follows: control: no probiotic supplementation; Pro1x: B. subtilis supplementation at 1.875 × 105 CFU/g diet; and Pro10x: B. subtilis supplementation at 1.875 × 106 CFU/g diet. Body weight at d 14 postweaning (p = 0.06) and average daily gain for d 0 to 14 postweaning (p < 0.05) were greater in the Pro1x treatment than in the other treatments. Blood glucose levels were greater in both probiotic treatments than in the control treatment at d 14 postweaning (p < 0.05). In the fecal short-chain fatty acid (SCFA) concentrations, the butyrate concentrations were greater in the Pro1x treatment than in the other treatments (p < 0.05), and the acetate, propionate, and total SCFA concentrations were greater in the Pro1x treatment than in the Pro10x treatment (p < 0.05). The beta diversity of fecal microbiome composition at d 14 postweaning based on Unweighted Unifrac analysis was dissimilar between the Pro1x and Pro10x treatments (p < 0.05). In conclusion, dietary B. subtilis supplementation of two strains selected to reduce effects of pathogenic Escherichia coli to nursery diets at 1.875 × 105 CFU/g diet improved the growth rate in the early postweaning period, increased fecal SCFA concentrations and altered the fecal microbial community composition. A higher dose of B. subtilis did not improve the performance parameters over those of the control piglets.

Pathogenicity Studies of NADC34-like Porcine Reproductive and Respiratory Syndrome Virus LNSY-GY and NADC30-like Porcine Reproductive and Respiratory Syndrome Virus GXGG-8011 in Piglets.

The porcine reproductive and respiratory syndrome virus (PRRSV) has caused significant economic losses to the swine industry. The U.S., China, and Peru have reported NADC30-like or NADC34-like PRRSV-infected piglets, which have been identified as the cause of a significant number of abortions in clinics. Although the pathogenicity of NADC30-like PRRSV and NADC34-like PRRSV in piglets exhibits significant variability globally, studies on their pathogenicity in China are limited. In this study, the animal experiments showed that within 8-14 days post-infection, both piglets infected with NADC30-like PRRSV GXGG-8011 and those infected with NADC34-like PRRSV LNSY-GY exhibited significant weight loss compared to the control piglets. Additionally, the viremia of the LNSY-GY persisted for 28 days, while the viremia of piglets infected with the GXGG-8011 lasted for 17 days. Similarly, the duration of viral shedding through the fecal-oral route after the LNSY-GY infection was longer than that observed after the GXGG-8011 infection. Furthermore, post-infection, both the LNSY-GY and GXGG-8011 led to pronounced histopathological lesions in the lungs of piglets, including interstitial pneumonia and notable viral colonization. However, the antibody production in the LNSY-GY-infected group occurred earlier than that in the GXGG-8011-infected group. Our research findings indicate that LNSY-GY is a mildly pathogenic strain in piglets, whereas we speculate that the GXGG-8011 might be a highly pathogenic strain.

PSIV-5 The Utilization of Alltech’s Seed, Feed, Weed Piglet Program as an Alternative to Zinc Oxide on the Growth, Feed Efficiency and Mortality of Newly Weaned Pigs

Abstract Achieving a healthy gut with a suitable microbial population in place will maximize the health and lifetime performance of piglets and, concurrently, profitability. Natural nutritional strategies that promote gut health and development in young pigs without zinc oxide (ZnO) are gaining considerable interest. Alltech’s Seed, Feed, Weed (SFW) program is designed to promote favorable microbial communities in the gut, optimize gut structures, and support the immune system; all of which will positively impact the growth and health of young piglets. The objective of this study was to investigate the effect of the SFW piglet program as an alternative to ZnO supplementation on the growth, feed efficiency and mortality of newly weaned pigs. Newly weaned pigs were allocated to one of two dietary treatments in 3 experiments. All experiments were carried out on commercial pig units in Spain. Dietary treatments were a basal pre-starter and starter diet containing 3,000 ppm ZnO (CONTROL), and a SFW piglet pre-starter and starter pack containing 0 ppm ZnO (SFW). In Exp. 1, pigs (n = 431) were weaned at 28 days old and fed the experimental pre-starter diets for 9 days. In Exp. 2, pigs (n = 295) were weaned at 28 days old and fed the experimental pre-starter and starter diets for 35 days. In Exp. 3, pigs (n = 311) were weaned at 28 days old and fed the experimental pre-starter and starter diets for 21 days. Pig performance was recorded. In experiment 1, SFW-fed pigs had similar average daily gain (ADG; 142 g/d vs 148 g/d) and average daily feed intake (ADFI; 149 g/d vs. 167 g/d) to CONTROL fed pigs. Feed efficiency (FE) was 1.05 and 1.13 for SFW and CONTROL piglets, respectively, resulting in SFW fed piglets being heavier at the end of the treatment period (7.65 kg vs. 7.45 kg). In experiment 2, overall, ADG (308 g/d vs. 316 g/d) and ADFI (423 g/d vs. 444 g/d) were similar between SFW and CONTROL fed piglets, respectively. Th SFW piglets had greater FE than CONTROL pigs (1.37 vs. 1.41). In experiment 3, there was no effect of treatment on ADG (356 g/d vs. 355 g/d) and ADFI (410 g/d vs. 420 g/d) or piglet body weight at the end of the study (12.8 kg vs. 12.7 kg). Feed efficiency was improved (1.21 vs. 1.24) and piglet mortality was reduced (3.4 % vs. 6.9 %) in SFW fed piglets compared with CONTROL fed piglets. In conclusion, the SFW program may prove to be a suitable alternative to ZnO by positively influencing the gut health of piglets and ensuring that piglet performance and health is maintained in the absence of ZnO.

278 Effects of Yeast Postbiotic Supplementation on the Gut Bacterial Community Composition of Sows and Microbial Succession of Subsequent Offspring

Abstract Development of the gut microbiome in piglets via microbial succession is critical for maximizing their productivity and providing stability for overcoming weaning stress. The purpose of this trial was to investigate whether a yeast postbiotic could impact the sow fecal microbiome as well as affect microbial succession in piglets. Sows were fed a control (CON) diet, or a diet supplemented with a yeast-based postbiotic (SUP) at 0.5% from d 80 to d 113 of gestation and at 0.2% during lactation (d 114 of gestation to weaning at 20 ± 2 d). Fecal bacterial composition was determined for 12 sows/treatment at d 85 gestation, d 1 lactation, and weaning and 1 piglet/sow at weaning and d 7, d 14, and d 28 post-wean using Illumina MiSeq 2X300 sequencing of PCR-amplicons generated from the V1-V3 regions of the 16S rRNA gene. A comparative analysis of the most highly represented Operational Taxonomic Units (OTU) was performed using the non-parametric Kruskal-Wallis sum-rank test and Wilcoxon pairwise test. In this initial comparative analysis, no significant differences between sows which received CON or SUP diets or piglets were observed (P &amp;gt; 0.05), although, fluctuations in the abundance of specific OTUs were found over time in both sows and piglets. For instance, the abundance of OTU JK_30-00008, predicted to be a strain of Lactobacillus amylovorous, was increased sows at d85 (CON: 9.01%; SUP: 12.04%), dramatically reduced at d 1 of lactation (CON: 1.00%; SUP: 3.03%), then recovered by weaning (CON: 9.41%; SUP: 9.74%). In contrast, the abundance of OTU JK_16-00021, predicted to be an uncultured Peptostreptococcaceae, remained increased in sow fecal samples from both treatment groups at d 85, d 1 lactation, and weaning (CON: 10.6%, 15.05%, and 15.61%; SUP: 8.98%, 13.65%, and 14.47%, respectively). In piglet fecal samples, the most abundant OTUs at weaning, d 7, d 14, and d 28 were: JK_45-00042 (CON: 27.26%; SUP: 20.05%; no affiliation to any currently defined phylum), JK_137-00038 (CON: 11.04%; SUP: 5.76%; unclassified Yersiniaceae), JK_30-00008 (CON: 13.64%; SUP: 14.11%; Lactobacillus amylovorous), and JK_51-00117 (CON: 7.66%; SUP: 5.32%; Prevotella copri), respectively. In piglets, the number of OTUs representing 50% of total sequence relative abundance increased with time (n = 5 OTUs at weaning, n = 18 at d 7, n = 17 at d 14, and n = 43 at d 28) suggesting an increase in diversity with age. Yeast postbiotic in sow diet had limited impact on relative proportions of sow fecal microbiome and offspring microbial succession after weaning with greater piglet diversity expected due to dietary changes. In addition, several of the OTUs in greatest relative abundance in piglets, including JK_45-00042, JK_137-00038, JK_-42, and JK_-49 did not correspond to valid bacterial species. Together, these results underscore the need to identify prevalent unknown bacterial species in microbial community compositional shifts in the period around weaning.

Protective efficacy of a candidate live attenuated vaccine derived from the SD-R strain of lineage 1 porcine reproductive and respiratory syndrome virus against a lethal challenge with HP-PRRSV HuN4 in piglets.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen endangering the swine industry worldwide. Our previous study confirmed that the live attenuated vaccine SD-R strain could provide broad cross-protection against homologous and heterologous NADC30-like viruses. However, it is unclear whether SD-R can provide protection for piglets against HP-PRRSV. In the present study, 4-week-old PRRSV-free piglets were vaccinated intramuscularly with 106.2 TCID50 of SD-R and then challenged intramuscularly (2 mL) and intranasally (2 mL) with HP-PRRSV HuN4 (1 × 105.0 TCID50/mL). The results showed that two of five piglets died in the HuN4 challenge group and five of five immunized piglets survived in the immune challenge group. Five piglets in the HuN4 challenge group had a fever for 6-12 days and showed obvious clinical symptoms, but 3 of 5 piglets had a fever for only 1 day at 5 days post inoculation, and only 1 of the 5 piglets in the immune challenge group had a cough. Compared to challenged control piglets, vaccinated piglets had significantly improved daily weight gain and obviously alleviated pathological lesions. Furthermore, piglets immunized with SD-R had reduced thymus atrophy caused by HP-PRRSV HuN4. These results demonstrate that the lineage 1 PRRSV attenuated vaccine SD-R strain provides protection against lethal HP-PRRSV HuN4 challenge. As such, it is a promising vaccine candidate for use against PRRSV infection. IMPORTANCE Both highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) and NADC30-like PRRSV have caused tremendous economic losses to the Chinese pig industry. In this study, a good challenge model was established to evaluate the protection afforded by the candidate SD-R vaccine against infection with a representative HP-PRRSV strain (HuN4). The control piglets in the challenge experiment displayed obvious clinical symptoms of PRRSV infection, with a mortality rate up to 40%. In contrast, all the piglets in the vaccinated challenged group survived, and only some pigs had transient fever. The daily gain of SD-R immunized group piglets was significantly increased, and the pathological changes were significantly reduced. In addition, the viral replication levels in the serum of the immunized group were significantly lower than those of the challenged control group. The live attenuated vaccine SD-R strain can provide protection against HP-PRRSV challenge, indicating that the SD-R strain is a promising vaccine candidate for use in the swine industry.

Gut Microbiota-Derived 5-Hydroxyindoleacetic Acid Alleviates Diarrhea in Piglets via the Aryl Hydrocarbon Receptor Pathway.

With the improvement in sow prolificacy, formula feeding has been increasingly used in the pig industry. Diarrhea remains a serious health concern in formula-fed (FF) piglets. Fecal microbiota transplantation (FMT) is an efficacious strategy to reshape gut microbiota and the metabolic profile for treating diarrhea. This study aims to investigate whether FMT from breast-fed piglets could alleviate diarrhea in FF piglets. The piglets were randomly assigned to the control (CON) group, FF group, and FMT group. Our results showed that FF piglets exhibited a higher diarrhea incidence, damaged colonic morphology, and disrupted barrier function. In contrast, FMT treatment normalized the morphology and barrier function. FMT suppressed the JNK/MAPK pathway and production of proinflammatory cytokines. Additionally, FF piglets had a lower abundance of the beneficial bacterial genus Bifidobacterium compared to CON piglets. Following FMT administration, Bifidobacterium was restored. Meanwhile, 5-HIAA, a metabolite of tryptophan, and AHR-responsive CYP1A1 and CYP1B1 were upregulated. Importantly, integrated multiomics analysis revealed a strong positive correlation between Bifidobacterium and 5-HIAA. In vitro, 5-HIAA supplementation reversed the LPS-induced disruption of tight junctions and production of proinflammatory cytokines in IPEC-J2 cells. In conclusion, FMT reduced diarrhea incidence and improved growth performance. The alleviative effect of FMT on diarrhea was associated with Bifidobacterium and 5-HIAA.

Enhanced ileum function in weaned piglets via Laminaria digitata and alginate lyase dietary inclusion: A combined proteomics and metabolomics analysis

Laminaria digitata, a brown seaweed with prebiotic properties, can potentially enhance the resilience of weaned piglets to nutritional distress. However, their cell wall polysaccharides elude digestion by monogastric animals' endogenous enzymes. In vitro studies suggest alginate lyase's ability to degrade such polysaccharides. This study aimed to assess the impact of a 10% dietary inclusion of L. digitata and alginate lyase supplementation on the ileum proteome and metabolome, adopting a hypothesis-generating approach. Findings indicated that control piglets escalated glucose usage as an enteric energy source, as evidenced by the increased abundance of PKLR and PCK2 proteins and decreased tissue glucose concentration. Additionally, the inclusion of seaweed fostered a rise in proteins linked to enhanced enterocyte structural integrity (ACTBL2, CRMP1, FLII, EML2 and MYLK), elevated peptidase activity (NAALADL1 and CAPNS1), and heightened anti-inflammatory activity (C3), underscoring improved intestinal function. In addition, seaweed-fed piglets showed a reduced abundance of proteins related to apoptosis (ERN2) and proteolysis (DPP4). Alginate lyase supplementation appeared to amplify the initial effects of seaweed-only feeding, by boosting the number of differential proteins within the same pathways. This amplification is potentially due to increased intracellular nutrient availability, making a compelling case for further exploration of this dietary approach. SignificancePig production used to rely heavily on antibiotics and zinc oxide to deal with post-weaning stress in a cost-effective way. Their negative repercussions on public health and the environment have motivated heavy restrictions, and a consequent search for alternative feed ingredients/supplements. One of such alternatives is Laminaria digitata, a brown seaweed whose prebiotic components that can help weaned piglets deal with nutritional stress, by improving their gut health and immune status. However, their recalcitrant cell walls have antinutritional properties, for which alginate lyase supplementation is a possible solution. By evaluating ileal metabolism as influenced by dietary seaweed and enzyme supplementation, we aim at discovering how the weaned piglet adapts to them and what are their effects on this important segment of the digestive system.

Protective Efficacy of a Candidate Live-Attenuated Vaccine Derived from the SD-R Strain against NADC34-like Porcine Reproductive and Respiratory Syndrome Virus.

NADC34-like porcine reproductive and respiratory syndrome virus (PRRSV) strains were first detected in China in 2017 and became major circulating strains in 2021. Our previous study showed that the live-attenuated vaccine candidate SD-R strain could provide broad cross-protection against different NADC30-like PRRSVs (sublineage 1.8). However, the protective effect of SD-R against NADC34-like PRRSV is unclear. Here, a novel NADC34-like PRRSV, LNTZJ1341-2012, was isolated from a pig farm experiencing disease in 2020. Sequence analysis revealed that LNTZJ1341-2012 belonged to PRRSV-2 sublineage 1.5, exhibited the same Nsp2 amino-acid deletion characteristics as IA/2014/NADC34, and had not recombined with other strains. Additionally, a good challenge model was established to evaluate the protection afforded by the candidate SD-R vaccine against infection with a representative NADC34-like strain (LNTZJ1341-2012). The control piglets in the challenge experiment displayed clinical signs typical of PRRSV infection, including transient fever, high viremia, mild clinical symptoms, and histopathological changes in the lungs and submaxillary lymph nodes. In contrast, SD-R vaccination significantly reduced serum and lung tissue viral loads, and vaccinated piglets did not show any clinical symptoms or histopathological changes. Our results demonstrated that LNTZJ1341-2012 is a mildly virulent NADC34-like PRRSV and that the live-attenuated vaccine SD-R can prevent the onset of clinical signs upon challenge with the NADC34-like PRRSV LNTZJ1341-2012 strain, indicating that SD-R is a promising vaccine candidate for the swine industry.