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Lactating sows and their litters are particularly vulnerable to heat stress (HS). HS decreases sow fertility, feed intake, milk production, and litter growth. Approaches are needed to mitigate the negative effects of HS on animal welfare and reduce oxidative damage to tissues associated with HS. Recently, electronic cooling pad (ECP) were designed to remove heat through conductive cooling. The objective of this study was to test the efficacy of ECP and feeding an antioxidant, Moringa oleifera(4% of the diet, M), to sows from late gestation to weaning on their welfare and production performance. A study was conducted using a 2 by 2 factorial arrangements of treatments with mixed parity Yorkshire x Landrace sows (n = 48) mated to Duroc sires. The sows were exposed to moderate HS conditions from gestation d 100 to d 21 of lactation (weaning). To achieve moderate HS analogous to a summer day, farrowing room temperature was increased incrementally from 800 to 1100 h to 32º C and slowly decreased to 26 ºC from 1700 to 2000 h. Sows were limit-fed their specific diets during gestation (1.36 kg 2X/d) and fed for ad-libitum feed intake post farrowing. Treatments included HS+control corn-soy meal diet (CS), HS+M, ECP+CS, ECP+M (n = 12/treatment). Sow RR and RT were measured four times daily (0600, 1300, 1600, 1900 h) and sow feed intake during lactation was measured along with body weight (BW) change from farrowing to weaning. Birth litter size was determined, and growth of standardized litters (n = 13 piglets/sow) was measured. Milk was collected during active farrowing (d 0) and on d 3 and d 14 post-farrowing and analyzed for macronutrient content. The use of ECP decreased lactating sow RR (Lsmeans HS = 66.5 bpm, ECP = 28.2 bpm, P≤ 0.0001), RT (Lsmeans HS = 39.2 ºC, ECP = 38.8 ºC, P= 0.003), and lactation BW loss (Lsmeans HS = -21.67, ECP = -5.1 kg P= 0.002). ECP by time-of-day interactions (P< 0.01) existed for RR and RT with ECP having a greater impact from 1300 to 1900 h than at 0600 h. ECP increased lactation feed intake (P< 0.02). An ECP by diet interaction (P= 0.0004) indicated ECP increased lactation feed intake for the sows fed the CS diet (6.48 kg/d vs 4.42 kg/d, P= 0.0004) but did not affect feed intake of sows fed the M diet. Treatment did not affect litter weaning weight (P= 0.14). M increased percent fat in milk (Lsmeans M = 12.28, CS = 11.06, P= 0.05) across all days of lactation. The reduction in sow RR and RT combined with increased feed intake and decreased loss of BW during lactation indicate that ECP improved sow wellbeing in the HS environment. Neither cooling nor M affected litter growth, despite increased fat content of milk of M supplemented sows and increased feed intake of ECP-CS sows.

Sow milk serves as a crucial source of nutritional, immunological, and growth-promoting components for the piglets. Our previous studies established that maternal live yeast (LY) supplementation altered the expression of antioxidant and immune-regulatory genes in the intestinal mucosa of suckling piglets. The current study aimed to investigate the effects of maternal LY supplementation during late gestation and lactation on milk proteomic profile in dams and health of offspring under lipopolysaccharide (LPS) challenge. On d 77 of gestation, 40 sows were allocated to 2 dietary treatments: without (CON) or with LY supplementation at 0.05% of diet during gestation and 0.1% during lactation. Milk samples were collected on d 0, 10, and 18 post-partum (n = 6), respectively. Within 24 h postweaning, piglets from the CON and LY groups were intraperitoneally injected with sterile saline or LPS [25 μg/kg body weight (BW)] and divided into four groups (n = 8): 1) saline + CON (CS), 2) saline + LY (YS), 3) LPS + CON (CLPS), and 4) LPS + LY (YLPS). Data were analyzed in a 2 × 2 factorial arrangement with main effects of maternal diet and immunological challenge. Rectal temperature was measured hourly for 4 h post-injection after which piglets were euthanized. Results showed that LPS increased concentrations of serum tumor necrosis factor (TNF) -α and interlekin (IL) -10 (P< 0.05) and tended to increase IL-8 in the ileal mucosa of piglets (P< 0.10). At 3 h post-injection, YLPS piglets tended to have a lower rectal temperature than CLPS piglets (P< 0.10). YLPS piglets also had decreased protein levels of TNF-α in the ileal mucosa (P< 0.05), with a tendency for greater protein abundance of E-cadherin but decreased mRNA abundance of catalase (P< 0.10) in the jejunal mucosa at 4 h post-injection (P< 0.05). In addition, YLPS piglets had less mRNA abundance of TLR2 and TLR4 in the liver than CLPS piglets (P< 0.05). With shotgun proteomics analysis, we found that milk of LY sows had more abundant proteins associated with immunity, including immunoglobulin and complement protein (Ig-like and C1q domain-containing proteins) on d 0 and d 10. Insulin-like growth factor binding protein (IGFBP) 5 was also more abundant in the d 0 milk of LY sows, whereas prostaglandin synthase was greater in d 10 and d 18 milk of CON sows. Additionally, pathway analysis showed that proteins identified in the milk of CON sows have roles in neutrophil degranulation and IL-12 signaling and production, whereas pathways associated with regulation of complement system, IGF and DHCR24 signaling, were enriched in the milk of LY sows. These results suggest that maternal LY supplementation could protect newly weaned piglets from bacteria endotoxin effect by suppressing inflammatory response, improving expression of tight junction proteins in offspring, and altering immune-associated proteins in sow milk.

Lactating sows are particularly vulnerable to heat stress (HS) due to the increased metabolism from milk production. A greater understanding of HS response could assist in mitigating its detrimental effects on animal production. Two core circadian clock genes were pinpointed in a recent genome study as potential mediators of HS response, indicating the possible alteration of circadian clocks by HS exposure. This study aimed to assess how cooling of lactating sows under natural heat stress conditions in the summer influenced circadian patterns of respiration rate (RR), rectal temperature (RT), behaviors, salivary concentration of cortisol and melatonin, milk cell populations and relative abundance of multiple cytokines in saliva. Lactating sows of mixed parities were divided into two treatment groups: treated with electronic cooling pad (C; n=9) and heat-stressed control (H; n=9). Experiments were conducted during two 48 h periods of increased environmental temperatures from summer heatwaves. During the initial 48 h period, rectal temperature (RT) was monitored every 60 min, rectal temperature (RT) every 30 min, and behaviors of eating, standing, sitting, laying, sleeping, drinking, and nursing every 5 min. Morning milk samples were collected following the completion of the first phase and utilized to categorize and count somatic cells. The second trial was approximately 1 wk later, and during this period saliva samples were collected every 4 h over the 48-h period. Results were analyzed for significant effect of treatments and interaction using periodic regression while circadian patterns were further detected by incorporating a Fourier series model utilizing sine-cosine variables that denote a fit and/or shift in circadian pattern. The analysis revealed that cooling decreased RT and RR while also modifying circadian patterns (P< 0.05). Cooling had no impact on the percentage of time spent in any activity over the 48-h period (P> 0.05). Nevertheless, the daily patterns of eating, standing, and sitting were different between the treatments (P< 0.05). A shift in eating time to later in the day in H sows relative to C sows related to a second rise in RT during the dark phase of the light-dark cycle (P< 0.05). Saliva melatonin concentrations were increased in C sows and circadian pattern altered relative to H (P< 0.05), but there was no effect on salivary cortisol concentrations (P> 0.05). Cooling reduced milk lymphocytes (P< 0.05) and influenced diurnal pattern of saliva cytokines including interleukins (IL) IL-1 alpha, IL-1 beta, IL-10, and IL-15 and transforming growth factor-beta 1. In conclusion, the cooling of heat-stressed sows altered the circadian patterns of physiology, behavior and melatonin, suggesting the need for additional research to investigate whether circadian disruption contributes to reduced production efficiency observed in HS animals.

Heat stress (HS) alters physiological and metabolic processes in lactating sows leading to decreased milk production, which is a major factor limiting growth and survivability of piglets. While genomic selection for thermotolerance may be a viable solution to alleviate the negative effects of HS on pig welfare, it may be linked to a reduction in milk production and subsequently, litter growth performance. Therefore, the study objective was to evaluate the effects of genomic selection for thermotolerance and its interaction with early gestational HS on biomarkers of mammary gland development in replacement gilts. We hypothesized that HS exposure as well as genomic selection for thermotolerance would negatively affect mammary epithelial proliferation rate. A total of 36 Landrace (33%) × Large White (67%) crossbred gilts divergently selected for thermotolerance (TOL; n = 18) or thermosensitivity (SEN; n = 18) were balanced by body weight, bred to a single Duroc sire, and then exposed to either thermoneutral (TN; constant 17 to 22°C) or cyclical HS (26 to 36°C) conditions until d 65 of gestation. From d 66 of gestation until farrowing, all pregnant gilts were exposed to TN conditions. Of the 36 total gilts bred, only 28 became pregnant yielding 15 HS gilts (n = 8 SEN and 7 TOL) and 13 TN gilts (n = 7 SEN and 6 TOL). On d 105 of gestation, a mammary biopsy was taken from all gilts, mammary tissue was placed into 10% buffered formalin, and KI67 immunohistochemical staining was performed to identify proliferating mammary epithelial cells (MEC). Proliferating and non-proliferating MEC populations were counted using ImageJ tool. Data were analyzed using PROC GLM in SAS 9.4 with individual gilt as the experimental unit. Overall, early gestational HS decreased (P< 0.01; 16.53 ± 2.12%) the percent of proliferating MEC relative to those kept under TN conditions (26.42 ± 2.39%). However, no effect of genomic line divergence was detected with any comparison (P> 0.05). In conclusion, early gestation HS, but not genomic selection for thermotolerance, had a negative impact on biomarkers of mammary gland development in replacement gilts. These data may suggest that early gestation HS could have a reductive effect on milk production capacity, which may negatively affect litter growth.

Recent studies have highlighted the importance of maternal nutrition during gestation and lactation in modulating the gastrointestinal development and health of offspring. Therefore, the objective of this study was to determine the effects of live yeast (LY) supplementation to sows during late gestation and throughout lactation on markers of gut health of piglets prior to weaning and immediately postweaning. On day 77 of gestation, forty sows were allotted based on parity and expected farrowing dates to two dietary treatments: without (CON) or with (LY) supplementation at 0.05% and 0.1% of diet during gestation and lactation, respectively. On postnatal days (PND) 0, 10, 18, and postweaning days (PWD) 7 and 14, one piglet from each of 10 sows per treatment were selected for intestinal tissue collection (n= 10). Real-time PCR and western blotting analyses were used to determine the mucosal expression of immune and antioxidant-regulatory genes and tight junction markers of gut health in the duodenum, jejunum, and ileum. Inflammatory and tight junction markers on PND 0 were not affected by maternal dietary treatment. On PND 18, maternal LY supplementation increased (P< 0.05) mRNA expression of interleukin(IL)-6and tended (P= 0.08) to increase expression of IL-10in the ileal muocsa. Maternal LY supplementation also increased (P< 0.05) expression of IL-1βin the ileal mucosa on PWD 14. Likewise, expression of superoxide dismutase(SOD) 1was increased (P< 0.05) by LY on PND 10, 18, and PWD 14, with a tendency (P= 0.09) for a greater mRNA abundance of catalaseon PND 14 in the ileal mucosa. Compared to CON piglets, LY piglets had a higher (P< 0.05) protein abundance of E-cadherin in the jejunal mucosa on PND 0, PWD 7, and PWD 14. Levels of occludin and claudin-4 were also higher (P< 0.05) in the jejunum of LY piglets on PWD 14. No differences were found in jejunal histomorphological measurements between treatments. In conclusion, this study shows that maternal LY supplementation affects key markers of gut health and development in the offspring that may impact the future growth potential and health of newborn piglets.Maternal live yeast supplementation during gestation and lactation affects intestinal homeostasis of offspring by regulating the expression of tight junction proteins, inflammatory cytokines, and antioxidant capacity.Increasing evidence supports the benefits of improving sow nutrition during gestation and lactation to promote gastrointestinal development and overall health of piglets. The objective of this research was to investigate the effects of maternal live yeast (LY) supplementation to sows during late gestation and lactation periods on the intestinal health of suckling and weaned piglets. Sows were fed LY during gestation and lactation and piglets were killed for sampling at different time points to track the temporal effect of maternal LY supplementation on changes in markers of intestinal health and development on postnatal days 0, 10, and 18, and postweaning days 7 and 14. Results showed that maternal LY supplementation affected several markers of health and development in the offspring, especially the expression of tight junction proteins, inflammatory cytokines, and antioxidant enzymes. These results indicate that nutritional intervention during gestation and lactation could serve as an effective strategy for raising piglets with better health and growth performance.