Weaning Stress Research Articles

Associations between resilience to weaning stress and startle response in nursery age gilts

Resilience is the capacity of animals to return quickly to their pre-stress status following a disturbance, including social, physical, and/or disease challenges. In modern farming, where there are many stressors, resilience is crucial for pigs because it affects their welfare and production. The goal of the study was to assess whether behavioral response to an auditory stimulus during a startle test (acute stress) differed between pigs designated at weaning (27 +/- 2d of age) as stress-resilient (SR) or stress-vulnerable (SV). Blood samples were collected from female piglets (n = 170) from 26 litters surrounding weaning at multiple time points. Using serum cortisol levels from these samples, two female pigs from each litter (n = 52) were classified as either SR (n = 26) or SV (n = 26) and used for the startle test. The startle test was conducted when pigs were 7wk-of-age while they were housed in the nursery room and recordings were captured utilizing cameras positioned on the ceiling. We assessed startle magnitude score (SM) and time to resume home pen behavior as indicators of the pigs’ behavioral responses. In addition to stress resilience designation, pigs’ relaxed-tense score (RT), orientation to stimulus (OS), and pen position were also observed which may affect startle response. Our data suggest no relationship between behavioral response to an auditory startle test and resilience or vulnerability to weaning stress. The difference in the type of stressors needs to be considered as an acute, simple auditory stimulus was used for the startle test and a longer-lasting, multi-modal weaning stress was used for initial resilience designation. However, the startle test could be a relatively easy way to assess the fearfulness of pigs on farms, as it requires no training of pigs and can be conducted in the home pen, but further methodological improvement is required. Though our results did not support a clear connection between a behavioral fear response and physiological stress resilience, examining the resilience of pigs during their early developmental phases using behavioral markers is worthwhile. Early detection of non-resilient animals could offer the opportunity to implement more effective management strategies beginning earlier in life when pigs might be more vulnerable to stressors or the effects more long-lasting, thereby improving the welfare of pigs. Furthermore, it facilitates the selection of robust animals for future breeding. Further research is required to identify behavioral traits clearly indicative of stress resilience.

Role of the GLP2–Wnt1 axis in silicon-rich alkaline mineral water maintaining intestinal epithelium regeneration in piglets under early-life stress

Stress-induced intestinal epithelial injury (IEI) and a delay in repair in infancy are predisposing factors for refractory gut diseases in adulthood, such as irritable bowel syndrome (IBS). Hence, it is necessary to develop appropriate mitigation methods for mammals when experiencing early-life stress (ELS). Weaning, as we all know, is a vital procedure that all mammalian newborns, including humans, must go through. Maternal separation (MS) stress in infancy (regarded as weaning stress in animal science) is a commonly used ELS paradigm. Drinking silicon-rich alkaline mineral water (AMW) has a therapeutic effect on enteric disease, but the specific mechanisms involved have not been reported. Herein, we discover the molecular mechanism by which silicon-rich AMW repairs ELS-induced IEI by maintaining intestinal stem cell (ISC) proliferation and differentiation through the glucagon-like peptide (GLP)2–Wnt1 axis. Mechanistic study showed that silicon-rich AMW activates GLP2-dependent Wnt1/β-catenin pathway, and drives ISC proliferation and differentiation by stimulating Lgr5+ ISC cell cycle passage through the G1–S-phase checkpoint, thereby maintaining intestinal epithelial regeneration and IEI repair. Using GLP2 antagonists (GLP23−33) and small interfering RNA (SiWnt1) in vitro, we found that the GLP2–Wnt1 axis is the target of silicon-rich AMW to promote intestinal epithelium regeneration. Therefore, silicon-rich AMW maintains intestinal epithelium regeneration through the GLP2–Wnt1 axis in piglets under ELS. Our research contributes to understanding the mechanism of silicon-rich AMW promoting gut epithelial regeneration and provides a new strategy for the alleviation of ELS-induced IEI.

73 Deworming to improve growth in early-weaned spring born hair sheep lambs

Abstract In lambs, the stress of weaning and the lack of a fully developed immune system can increase susceptibility to gastrointestinal nematodes (GIN). Lack of an effective GIN control strategy around this time can have a significant impact on lamb growth, productivity and mortality. The objective of this study was to determine the influence of deworming at weaning on growth performance in hair sheep lambs. St. Croix (STX) and Barbados Blackbelly (BB) lambs used in the study were born on pasture, weaned at 60.2 ± 0.4 d of age, and transitioned in pens for 87 d post-weaning before turning out to pasture. After accounting for initial FAMACHA eyelid color score, breed, and birth type (single or multiple) at weaning, 54 STX (n = 32) and BB (n = 22) lambs weighing 11.7 ± 0.4 kg were dewormed (DEW) or not (CON) with a combination of levamisol (Prohibit; 8 mg/kg BW) moxidectin (Cydectin; 0.2 mg/kg BW) and albendazole (Valbazen; 7.5 mg/kg BW). To evaluate the effect of deworming treatment, BW and body condition scores (BCS; scale 1-5) were recorded at weaning and at end of transition to pasture. Blood and fecal samples were also collected for determination of packed cell volume (PCV) and fecal egg counts (FEC). Pooled treatment group feces (d 0 – 98) were collected and cultured to determine GIN genera at weaning. Data were analyzed using repeated measures in a mixed model, and FEC were log transformed prior to analysis. There was a mixed population of GIN at weaning averaging 65% and 35% for H. contortus and Tricostrongylus spp. At weaning, BCS, PCV, and FEC were similar between treatment groups and averaged 1.6 ± 0.07, 36.5 ± 0.6%, and 399 ± 54.4 epg, respectively. Combination deworming reduced FEC by 99%. At turnout, DEW lambs (2.3 ± 0.1) tended (P = 0.08) to have greater BCS than CON lambs (2.0 ± 0.1) and PCV was greater (P < 0.001) in DEW versus CON lambs (37.2 ± 0.9 and 33.3 ± 0.8%, respectively). There was also a tendency (P = 0.09) for breed to influence BCS (2.3 ± 0.1 and 2.0 ± 0.1 for BB and STX, respectively). The FEC at turnout was not influenced by treatment or breed (496.7 ± 75.1 epg). Additionally, DEW lambs (131.8 ± 5.2) tended (P = 0.09) to grow faster than CON (119.9 ± 4.7 g/d) lambs, a difference more pronounced in STX DEW (g/d) than STX CON lambs (136 ± 6.1 vs 110 ± 6.5 g/d; P < 0.05). Even though deworming tended to promote faster growth rates in lambs used in this study, alternative, more sustainable, parasite control strategies should be considered in the wake of increasing dewormer resistance.

Review of yeast culture concerning the interactions between gut microbiota and young ruminant animals.

Microorganisms inhabit the gastrointestinal tract of ruminants and regulate body metabolism by maintaining intestinal health. The state of gastrointestinal health is influenced not only by the macro-level factors of optimal development and the physiological structure integrity but also by the delicate equilibrium between the intestinal flora and immune status at the micro-level. Abrupt weaning in young ruminants causes incomplete development of the intestinal tract resulting in an unstable and unformed microbiota. Abrupt weaning also induced damages to the microecological homeostasis of the intestinal tract, resulting in the intestinal infections and diseases, such as diarrhea. Recently, nutritional and functional yeast culture has been researched to tackle these problems. Herein, we summarized current known interactions between intestinal microorganisms and the body of young ruminants, then we discussed the regulatory effects of using yeast culture as a feed supplement. Yeast culture is a microecological preparation that contains yeast, enriched with yeast metabolites and other nutrient-active components, including β-glucan, mannan, digestive enzymes, amino acids, minerals, vitamins, and some other unknown growth factors. It stimulates the proliferation of intestinal mucosal epithelial cells and the reproduction of intestinal microorganisms by providing special nutrient substrates to support the intestinal function. Additionally, the β-glucan and mannan effectively stimulate intestinal mucosal immunity, promote immune response, activate macrophages, and increase acid phosphatase levels, thereby improving the body's resistance to several disease. The incorporation of yeast culture into young ruminants' diet significantly alleviated the damage caused by weaning stress to the gastrointestinal tract which also acts an effective strategy to promote the balance of intestinal flora, development of intestinal tissue, and establishment of mucosal immune system. Our review provides a theoretical basis for the application of yeast culture in the diet of young ruminants.

Effects of Different Feed Additives on Intestinal Metabolite Composition of Weaned Piglets.

To study the effects of different feed additives on the weaning stress of Tibetan piglets, we selected 28 healthy, 30-day-old Tibetan weaned piglets and divided them into four groups, namely, the control group (basal feed without any antibiotic additions) (Nor), the group with the addition of the antibiotic lincomycin (Ant), the group with the addition of fifteen-flavor black pills of Tibetan medicine (Tib), and the group with the addition of fecal bacterial supernatant (Fec). We measured growth performance, blood physiological indexes, and metabolomics. The results showed that the Ant, Tib, and Fec groups significantly reduced the ratio of diarrhea to feed/weight (F/G) and increased the average daily gain (ADG) compared with the Nor group (p < 0.01). The Nor group had significantly lower leukocyte counts, hemoglobin levels, and erythrocyte counts compared with the other three groups at 21 d (p < 0.05). These physiological indexes tended to stabilize at 42 d. We found that there were beneficial metabolites and metabolic pathways for gastrointestinal function. Specifically, the porphyrin metabolic pathway was elevated in the Ant group, and the tryptophan metabolic pathway was significantly elevated in the Tib and Fec groups compared with the Nor group (p < 0.05). In conclusion, adding fecal bacterial supernatant and fifteen-flavor black pills of Tibetan medicine to the feed reduced the rate of diarrhea and improved the growth performance of the piglets. Moreover, it had an effect on the microorganisms and their metabolites and pathways in the gastrointestinal tract of the animals, which might be the main reason for influencing the diarrhea rate of weaned Tibetan piglets and the growth and development of the piglets. This study provides a new approach for anti-stress applications in weaned Tibetan piglets and the development of substitute anti-products.

Purine Metabolism and Hexosamine Biosynthetic Pathway Abnormalities in Diarrheal Weaned Piglets Identified Using Metabolomics.

Post-weaning diarrhea significantly contributes to the high mortality in pig production, but the metabolic changes in weaned piglets with diarrhea remain unclear. This study aimed to identify the differential metabolites in the urine of diarrheal weaned piglets and those of healthy weaned piglets to reveal the metabolic changes associated with diarrhea in weaned piglets. Nine 25-day-old piglets with diarrhea scores above 16 and an average body weight of 5.41 ± 0.18 kg were selected for the diarrhea group. Corresponding to the body weight and sex of the diarrhea group, nine 25-month-old healthy piglets with similar sex and body weights of 5.49 ± 0.21 kg were selected as the control group. Results showed that the serum C-reactive protein and cortisol of piglets in the diarrhea group were higher than those in the control group (p < 0.05). The mRNA expression of TNF-α, IFN-γ in the jejunum and colon, and IL-1β in the jejunum were increased in diarrhea piglets (p < 0.05), accompanied by a reduction in the mRNA expression of ZO-1, ZO-2, and CLDN1 in the jejunum and colon (p < 0.05); mRNA expression of OCLN in the colon also occurred (p < 0.05). Metabolomic analysis of urine revealed increased levels of inosine, hypoxanthine, guanosine, deoxyinosin, glucosamine, glucosamine-1-p, N-Acetylmannosamine, chitobiose, and uric acid, identified as differential metabolites in diarrhea piglets compared to the controls. In summary, elevated weaning stress and inflammatory disease were associated with the abnormalities of purine metabolism and the hexosamine biosynthetic pathway of weaned piglets. This study additionally indicated the presence of energy metabolism-related diseases in diarrheal weaned piglets.

Effects of Spinach Extract and Licorice Extract on Growth Performance, Antioxidant Capacity, and Gut Microbiota in Weaned Piglets.

Anemia and weaning stress are important factors affecting piglet growth performance. Spinach extract and licorice extract have been used to improve anemia and antioxidant capacity, respectively. However, whether they have synergistic effects has not been reported. To evaluate the effects of mixed spinach extract and licorice extract on growth performance, serum biochemistry, antioxidant capacity, and gut microbiota in weaned piglets, a total of 160 weaned piglets were randomly allotted to four treatments with four replications of 10 piglets each. The four treatments were as follows: control (CON) group (basal diet), spinach extract (SE) group (basal diet + 1.5 kg/t spinach extract), licorice extract (LE) group (basal diet + 400 g/t licorice extract), and spinach extract and licorice extract (MIX) group (basal diet + 1.5 kg/t spinach extract + 400 g/t licorice extract). The results showed that, compared with the CON group, diets supplemented with spinach extract and licorice extract significantly increased the average daily gain (p < 0.05), while considerably reducing the feed-to-gain ratio (p < 0.05). Moreover, the MIX group exhibited a significant up-regulation of serum total protein, globulin, albumin, glucose, and triglyceride levels in comparison to the CON group (p < 0.05). Meanwhile, both the anemia and antioxidant capacity of piglets were effectively improved. Notably, the MIX group achieved even better results than the individual supplementation in terms of enhancing growth performance, which could potentially be attributed to the increased abundance of the Rikenellaceae_RC9_gut_group. These results demonstrated that the supplementation of diets with spinach extract and licorice extract improves the absorption of nutrients from the diet and antioxidant capacity in weaned piglets.

Pioneering gut health improvements in piglets with phytogenic feed additives

This research investigates the effects of phytogenic feed additives (PFAs) on the growth performance, gut microbial community, and microbial metabolic functions in weaned piglets via a combined 16S rRNA gene amplicon and shotgun metagenomics approach. A controlled trial was conducted using 200 pigs to highlight the significant influence of PFAs on gut microbiota dynamics. Notably, the treatment group revealed an increased gut microbiota diversity, as measured with the Shannon and Simpson indices. The increase in diversity is accompanied by an increase in beneficial bacterial taxa, such as Roseburia, Faecalibacterium, and Prevotella, and a decline in potential pathogens like Clostridium sensu stricto 1 and Campylobacter. Shotgun sequencing at the species level confirmed these findings. This modification in microbial profile was coupled with an altered profile of microbial metabolic pathways, suggesting a reconfiguration of microbial function under PFA influence. Significant shifts in overall microbial community structure by week 8 demonstrate PFA treatment’s temporal impact. Histomorphological examination unveiled improved gut structure in PFA-treated piglets. The results of this study indicate that the use of PFAs as dietary supplements can be an effective strategy, augmenting gut microbiota diversity, reshaping microbial function, enhancing gut structure, and optimising intestinal health of weaned piglets providing valuable implications for swine production.Key points• PFAs significantly diversify the gut microbiota in weaned piglets, aiding balance.• Changes in gut structure due to PFAs indicate improved resistance to weaning stress.• PFAs show potential to ease weaning stress, offering a substitute for antibiotics in piglet diets.

Remodeling of Hepatic Glucose Metabolism in Response to Early Weaning in Piglets.

This study aimed to investigate the dynamic changes in hepatic glucose metabolism in response to early weaning. A total of 60 piglets were randomly selected and weaned at 21 days old. Six piglets were slaughtered on the weaning day (d0) and at 1 (d1), 4 (d4), 7 (d7), and 14 (d14) days postweaning. The results illustrated that body weight significantly increased from d4 to d14 (p < 0.001). Serum glucose fell sharply after weaning and then remained at a low level from d1 to d14 (p < 0.001). Serum insulin decreased from d4 (p < 0.001), which caused hepatic glycogen to be broken down (p = 0.007). The glucose-6-phosphatase activity increased from d0 to d4 and then decreased from d4 to d14 (p = 0.039). The pyruvate carboxylase activity presented a significant sustained increase from d0 to d14 (p < 0.001). The succinate (p = 0.006) and oxaloacetate (p = 0.003) content on d4 was lower than that on d0. The succinate dehydrogenase activity (p = 0.008) and ATP (p = 0.016) production decreased significantly on d4 compared to that on d0. Taken together, these findings reveal the dynamic changes of metabolites and enzymes related to hepatic glycometabolism and the TCA (tricarboxylic acid) cycle in piglets after weaning. Our findings enrich weaning stress theory and might provide a reference for dietary intervention.

Effect of Pig Synthetic Pheromones and Positive Handling of Pregnant Sows on the Productivity of Nursery Pigs.

Weaning is one of the most important stress events in the life of pigs, increasing the risk for health problems and reduced performance. The release of pheromones in pig stables can be considered an environmental enrichment and alleviate the negative effects of weaning stress in nursery pigs. The present study investigated the effect of synthetic pheromones on the performance of nursery pigs. The effect of positive handling of sows in the farrowing house on the performance of the offspring in the nursery was also investigated. The study was performed in a commercial pig farm and included 24 batches of weaned piglets (216 piglets per batch). Half of the batches originated from sows exposed to positive handling. This implied that music was played from 6.00 a.m. to 6.00 p.m. from the moment the sows entered the farrowing house until weaning and that they were subjected to backscratching from the day they entered the farrowing unit the day of farrowing. During the nursery period, half of the batches were treated, and half served as controls. Piglets of treated groups were exposed to a synthetic analog of the maternal pig appeasing pheromone (PAP) (SecurePig®, Signs, Avignon, France). The product consisted of a gel block from which the pheromones were slowly released into the room. Different performance parameters were measured during the nursery period. Neither the sow treatment nor the treatment with pheromones significantly influenced the performance of the piglets during the nursery period (p > 0.05). The median values (95% confidence interval) of average daily gain, namely 318 (282-338) vs. 305 (272-322) g/day, feed conversion ratio, namely 1.64 (1.51-1.71) vs. 1.70 (1.57-1.75), and number of antimicrobial treatment days, namely 16.9 (9.6-25.0) vs. 17.3 (9.5-25.0) days, were numerically better in the nursery pigs exposed to the pheromones compared to the control groups. Mortality however was numerically higher in the treated groups, namely 4.4 (2.8-6.8) vs. 3.2 (0.9-4.2)%. Under the conditions of the present production system, pigs exposed to the pheromone treatment during the nursery did not show a significant performance increase.

Maternal docosahexaenoic acid supplementation during lactation improves exercise performance, enhances intestinal glucose absorption and modulates gut microbiota in weaning offspring mice.

Intestinal dysfunction induced by weaning stress is common during breastfeeding period. Docosahexaenoic acid (DHA) is well known for promoting visual and brain development, but its effects on early intestinal development remain unknown. This study investigated the impact of maternal DHA supplementation during lactation on intestinal glucose absorption and gut microbiota in weaning offspring mice. Dams were supplemented with vehicle (control), 150 mg/(kg body weight · day) DHA (L-DHA), or 450 mg/(kg body weight · day) DHA (H-DHA) throughout lactation by oral administration. After weaning, pups were randomly divided into three groups for athletic analysis, microbial and proteomic analysis, biochemical analysis, 4-deoxy-4-fluoro-D-glucose (4-FDG) absorption test, and gene expression quantitation of glucose transport-associated proteins and mTOR signaling components. The H-DHA group exhibited enhanced grip strength and prolonged swimming duration compared to the control group. Additionally, there were significant increases in jejunal and ileal villus height, and expanded surface area of jejunal villi in the H-DHA group. Microbial analyses revealed that maternal DHA intake increased the abundance of beneficial gut bacteria and promoted metabolic pathways linked to carbohydrate and energy metabolism. Proteomic studies indicated an increased abundance of nutrient transport proteins and enrichment of pathways involved in absorption and digestion in the H-DHA group. This group also showed higher concentrations of glucose in the jejunum and ileum, as well as elevated glycogen levels in the liver and muscles, in contrast to lower glucose levels in the intestinal contents and feces compared to the control group. The 4-FDG absorption test showed more efficient absorption after oral 4-FDG gavage in the H-DHA group. Moreover, the expressions of glucose transport-associated proteins, GLUT2 and SGLT1, and the activation of mTOR pathway were enhanced in the H-DHA group compared to the control group. The L-DHA group also showed similar but less pronounced improvements in these aspects relative to the H-DHA group. Our findings suggested that maternal DHA supplementation during lactation improves the exercise performance, enhances the intestinal glucose absorption by increasing the expressions of glucose transporters, and beneficially alters the structure of gut microbiome in weaning offspring mice.

An assessment on the impact of weaning stress on the weaning age in Black Bengal goat kids

Weaning is stressful for goat kids, often leading to stunted growth, weight loss, and mortality, with varied weaning times reducing overall productivity and profitability. The aim of this research was to determine the optimal age for weaning of Black Bengal goat (BBG) kids and evaluate the impact of weaning stress on their post weaning performances. A trial was conducted comprising four groups of eight kids each, accompanied by four lactating does, weaned at intervals of 45, 60, 75, and 90 days (designated as A, B, C, and D, respectively), and reared up to six months of age. Heart rate measurements and blood samples were taken three days before (-3), during (0), and three days after (+3) individual weaning schedules. Furthermore, dry matter intake, daily weight gain, weaning weight, 06 months weight, disease incidence, and kid mortality were also recorded. The serum concentration of triiodothyronine(T3) hormone declined significantly (p&lt;0.05) at +3 days after weaning than - 3 days before weaning in group A, B and C while an increase was observed in group D. The average cortisol level was significantly (p&lt; 0.05) lower in group D than other groups. Post weaning performances, including weaning weight, 06 months weight, daily weight gain and kid mortality also differ significantly (p&lt;0.05), group D demonstrating superior performance compared to group A, B and C. The findings revealed that, kids weaned at 75 to 90 days experienced less stress, performed better, and had fewer health issues.

The ileal microbiome and mucosal immune profiles in response to dietary supplementation of ultra-grinded Astragalus membranaceus in weaned goats.

Weaning goats are susceptible to diarrhea and have weakened immune functions due to physiological, dietary and environmental stresses. Astragalus membranaceus (A. membranaceus), a traditional Chinese medicinal herb, has been shown to improve growth performance and immunity in weaned ruminants. However, the influence mechanism of A. membranaceus on intestinal microbiota and mucosal immunity in weaned goats is still unknown. This study investigated the effects of ultra-grinded A. membranaceus (UGAM) on the immune function and microbial community in the ileum of weaned goats. Eighteen healthy weaned Xiangdong black goats (BW, 5.30 ± 1.388 kg) were used in a study of completely randomized block design with 28 days long. The animals were randomly assigned to either a basal diet supplemented with 10 g/d of milk replacer (CON, n = 9) or the CON diet supplemented with 10 g/head UGAM (UGAM, n = 9). Supplementation of UGAM increased (p < 0.05) the plasma concentrations of total protein and albumin. Meanwhile, the addition of UGAM reduced (p < 0.05) the relative mRNA expression of the IL-6 gene (a marker of inflammation), indicating the potential immunomodulatory effect of UGAM. Moreover, the relative abundances of Verrucomicrobiota and Mycoplasma were lower (p < 0.05) in the ileum of goats supplemented with UGAM than CON. These findings suggest that dietary supplementation of UGAM may have enhanced the ileum health of weaned goats by reducing inflammation factor expression and reducing the relative abundance of pathogenic microbes. The observed beneficial effects of ultra-grinded A. membranaceus on ileal mucosal immune and the community of ileal microbiota indicate its potential to be used as a viable option for promoting the well-being of weaned goats under weaning stress.

Dietary Qi-Weng-Huangbo powder enhances growth performance, diarrhoea and immune function of weaned piglets by modulating gut health and microbial profiles.

The evolution of nutritional strategies to improve the gut health and microbiota profiles of early-weaned piglets is essential to reduce diarrhoea caused by weaning stress. Therefore, the aim of this study was to determine the effects of dietary supplementation of Qi-Weng-Huangbo powder, a traditional herbal medicine consisting of a mixture of Pulsatilla chinensis, Chinese Schneid and Astragalus extracts (PCE), on the growth performance, diarrhoea rate, immune function and intestinal health of weaned piglets. 162 piglets were randomly assigned to the CON group (no PCE added), the PCEL group (300 mg/kg PCE) and the PCEH group (500 mg/kg PCE) at the end of the third week post farrowing. There were 9 replicates of each group with 6 pigs per replicate. The experiment lasted for 28 days and sampling was performed on the final day. The results showed that the PCE diet increased the average daily gain (ADG) and final body weight (BW) compared to the CON group. Both supplemented doses of PCE reduced the faecal scores of piglets, and the diarrhoea rate in the PCEL group was significantly lower than that in the CON group. The application of PCE diets promoted the development of the spleen in piglets and up-regulated serum immunoglobulin concentrations to enhance immune function, which was also reflected in the down-regulated gene expression of the colonic TLR/MyD88/NF-κB pathway. Supplementation with PCE improved intestinal morphology, and all doses of PCE significantly increased villus height (VH) in the ileum, whereas colonic crypt depth (CD) was significantly lower in the PCEH group than in the CON group. The PCEH diet significantly increased the levels of valeric and isovaleric acid in the colon content. Dietary PCEH also improved the colonic microbial community profile, reflected by a significant increase in Shannon's index compared with CON group. The abundance of Veillonellaceae and Rhodospirillales was significantly increased in the PCEH group at the family level. In conclusion, dietary PCE reduced diarrhoea rates, improved growth performance and enhanced immune function in weaned piglets. These improvements were potentially supported by altered ileum and colonic morphology, elevated colonic VFA levels, and modulation of colonic microbial profiles.

Effect of Mixed Lactiplantibacillus plantarum- and Bacillus subtilis-Fermented Feed on Growth, Immunity, and Intestinal Health of Weaner Pigs

Bamei pigs, an eximious local breed reared on the Tibetan Plateau of China, are facing problems such as feed shortages, weaning stress, and antibiotic abuse. This study aimed to improve the quality of feed, growth performance, intestinal microbiota, and immunity of Bamei pigs through feeding with potentially probiotic-fermented feed. Different feeds were administered to weaned Bamei piglets for 60 days, creating the following five experimental treatment groups: basal feed group; Lactiplantibacillus plantarum-fermented-feed group; Bacillus subtilis-fermented-feed group; mixed-fermented-feed group; and antibiotic-supplemented-feed group. The results showed that the pH, neutral detergent fiber, and acid detergent fiber of the potentially probiotic-fermented feeds were significantly reduced; organic acids were produced; and Coliform bacteria, Clostridium, and aerobic bacteria were effectively inhibited. Feeding with potentially probiotic-fermented feed not only reduced the feed-conversion ratio but also improved immunity by increasing the production of anti-inflammatory cytokines, as well as decreasing pro-inflammatory cytokines and typical inflammatory pathways. The 16s rDNA high-throughput-sequencing results showed that probiotic-fermented feed improved the diversity of intestinal microbiota, inhibited the growth of the opportunistic pathogens Clostridium and Streptococcus, increased the relative abundance of Lactobacillus and Prevotella, and promoted gut health, demonstrating the promising application prospects of potentially probiotic-fermented feed.

Effects of dietary traditional Chinese medicine residues on growth performance, intestinal health and gut microbiota compositions in weaned piglets.

Weaning stress can induce diarrhea, intestinal damage and flora disorder of piglets, leading to slow growth and even death of piglets. Traditional Chinese medicine residue contains a variety of active ingredients and nutrients, and its resource utilization has always been a headache. Therefore, we aimed to investigate the effects of traditional Chinese medicine residues (Xiasangju, composed of prunellae spica, mulberry leaves, and chrysanthemum indici flos) on growth performance, diarrhea, immune function, and intestinal health in weaned piglets. Forty-eight healthy Duroc× Landrace × Yorkshire castrated males weaned aged 21 days with similar body conditions were randomly divided into 6 groups with eight replicates of one piglet. The control group was fed a basal diet, the antibiotic control group was supplemented with 75 mg/kg chlortetracycline, and the residue treatment groups were supplemented with 0.5%, 1.0%, 2.0% and 4.0% Xiasangju residues. The results showed that dietary Xiasangju residues significantly reduced the average daily feed intake, but reduced the diarrhea score (P < 0.05). The 1.0% and 2.0% Xiasangju residues significantly increased the serum IgM content of piglets, and the 0.5%, 1.0%, 2.0% and 4.0% Xiasangju residues significantly increased the serum IgG content, while the 1.0%, 2.0% and 4.0% Xiasangju residues significantly increased the sIgA content of ileal contents (P < 0.05). Dietary Xiasangju residues significantly increased the villus height and the number of villus goblet cells in the jejunum and ileum, and significantly decreased the crypt depth (P<0.05). The relative mRNA expression of IL-10 in the ileum was significantly increased in the 1% and 2% Xiasangju residues supplemented groups (P < 0.05), while IL-1β in the ileum was downregulated (P < 0.05). Xiasangju residues improved the gut tight barrier, as evidenced by the enhanced expression of Occludin and ZO-1 in the jejunum and ileum. The diets with 1% Xiasangju residues significantly increased the relative abundance of Lactobacillus johnsonii, and 2% and 4% Xiasangju residues significantly increased the relative abundance of Weissella jogaeotgali (P < 0.05). Dietary supplementation with 0.5%, 1.0%, 2% and 4% with Xiasangju residues significantly decreased the relative abundance of Escherichia coli and Treponema porcinum (P < 0.05). In summary, dietary supplementation with Xiasangju residues improves intestinal health and gut microbiota in weaned piglets.

Effect of a Multi-Strain Probiotic on Growth Performance, Lipid Panel, Antioxidant Profile, and Immune Response in Andaman Local Piglets at Weaning

This study aimed to investigate the role of a multi-strain probiotic compound containing Bacillus mesentericus, Bacillus coagulans, Enterococcus faecalis, and Clostridium butyricum as an in-feed zinc oxide (ZnO) alternative in growth performance, diarrhea incidence, antioxidant profile, lipid panel, stress, and immunity in piglets at weaning. Seventy-two piglets weaned at 27 ± 1 day were divided randomly into three groups with four replicates of six piglets each: (i) a negative control group (WC) fed only a basal diet, (ii) a probiotic group (WB) fed a basal diet with the current probiotic formulation, and (iii) a positive control (PC) group fed a basal diet with 2500 mg/kg ZnO. The experiment was conducted for 28 days. Probiotic supplementation showed a positive effect on growth performance and reduced the diarrhea rate. The mean body weight of the piglets in the WB and PC groups was significantly higher than that of piglets in the WC group (14.88 ± 0.12, 14.97 ± 0.13 vs. 13.80 ± 0.06 kg; p ≤ 0.001). The addition of probiotic to the diet improved the lipid panel; the WB group showed a significantly higher level of high-density lipoprotein cholesterol (mg/dL) (32.67 ± 0.85 in WB vs. 12.48 ± 0.76 in WC; p ≤ 0.001) and lower levels of total cholesterol (mg/dL) (59.78 ± 1.97 in WB vs. 119.11 ± 2.12 in WC; p ≤ 0.001) and low-density lipoprotein cholesterol (mg/dL) (17.90 ± 1.12 in WB vs. 69.10 ± 3.37 in WC; p ≤ 0.001) compared with the negative control group. Moreover, probiotic supplementation enhanced the antioxidant defense system and provided protection from oxidative damage by increasing the concentrations of serum catalase, glutathione-S-transferase, and superoxide dismutase and by decreasing the concentrations of serum malonyldialdehyde and total nitric oxide. Heat shock proteins and other stress markers, such as serum cortisol, were reduced in the probiotic-fed group. The probiotic group also displayed higher levels of serum IgG and IgM at all time points and higher IgA on day 28 compared with the negative control group. Altogether, these results indicate that feeding with the currently used multi-strain probiotic formulation minimizes weaning stress, thereby improving the growth performance, antioxidant profile, lipid panel, and systemic and mucosal immunity. Therefore, multi-strain probiotic compounds may be used to replace ZnO in weaned piglets.

PSI-14 Weaning Stress Increases Bile Cysteine and Cysteinylglycine Concentrations in Pigs

Abstract Weaning is a critical time for pigs that is associated with nutritional, social, and environmental stressors that lead to reduced feed intake and poor nutrient utilization. Cysteine is a sulfur amino acid and a key constituent of glutathione (GSH), a major intracellular antioxidant and potential regulator of intestinal redox status. Glutathione is present in biliary secretions and may be an important source of cysteine to intestine in newly weaned pigs. The objective of this study was to determine amino thiol and amino acid concentrations in bile. Piglets (initial BW = 7,233 ± 683 g) were either weaned on day 21 of age (W; n = 9) and euthanized after 2 d or remained on the sow until day 23 of age (NW; n = 9) and were euthanized. Weaned pigs were fasted and allowed free access to water. After euthanasia, bile (directly from the gallbladder), jejunum, and ileum samples were collected. Bile amino acids and bile amino thiols were analyzed by reversed phase HPLC following precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate and 4-fluoro-7-aminosulfonylbenzofurazan, respectively. Reverse transcription quantitative real-time PCR was performed to measure cysteine transporter expression in jejunum and ileum. Cysteine concentration was greater in W than NW pigs (1,203 versus 324 ± 99 µmol/L; P &amp;lt; 0.0001). Both γ-glutamylcysteine (7.1 versus 2.2 ± 2.1 µmol/L), the direct precursor for GSH synthesis, and cysteinylglycine (203 versus 110 ± 30 µmol/L, the direct product of GSH degradation, were greater in W pigs than in NW pigs (P &amp;lt; 0.05). Bile GSH concentration tended to be greater in W than NW pigs (9.1 versus 5.3 ± 2.8 µmol/L; P = 0.07). Taurine, derived from cysteine oxidation, was greater in W than NW pigs (180 versus 91 ± 23 µmol/L; P &amp;lt; 0.05), whereas glutamate (11.4 versus 8.8 ± 1.9 µmol/L) and glycine (463 versus 403 ± 62 µmol/L), additional amino acid constituents of GSH, were not different between groups (P &amp;gt; 0.10). Expression of cysteine transporters SLC1A4, SLC1A5, SLC6A14, SLC6A19, SLC7A9, and SLC7A11 in jejunum and ileum were not different between groups (P &amp;gt; 0.10). Despite no feed intake after weaning, cysteine concentrations increase in bile. While this is likely due to bile accumulation in the gallbladder after weaning, high bile cysteine, cysteinylglycine, and glycine concentrations could potentially be a source of these amino acids for enterocytes during weaning stress.

262 Weaning-Induced Changes in Tissue Cysteine Utilization in Pigs

Abstract Weaning stress in pigs is associated with low and variable feed intake, poor nutrient utilization, and high feed costs. Cysteine is a sulfur amino acid with key roles in pig production, but how cysteine metabolism and requirements are affected by weaning stress should be better defined. The objective of this study was to determine weaning-induced changes in tissue cysteine metabolism. Pigs (initial BW = 7.23 ± 0.68 kg) were either weaned at 21 d age and euthanized at 23 d age (W; n = 9) or remained with the sow and euthanized at 23 d age (NW; n = 9). Weaned pigs were fasted to simulate acute nutritional stress but had free access to water. At euthanasia, blood, liver, jejunum, and ileum tissues were collected. Plasma and tissue amino acids and amino thiols were analyzed by HPLC. The abundance of proteins central to liver cysteine utilization were determined by immunoblot and enzyme activity assays. Glutathione (GSH) concentrations were less in jejunum (1,379 versus 1,720 ± 70 nmol/g; P &amp;lt; 0.01) and ileum (1,497 versus 1,740 ± 74 nmol/g; P &amp;lt; 0.05) in W than NW pigs. However, liver GSH concentration was not different between W and NW pigs (P &amp;gt; 0.10). While cysteine in jejunum and ileum were not affected by weaning (P &amp;gt; 0.10), γ-glutamylcysteine (γ-GC), the immediate precursor of GSH, declined in both jejunum (9.7 versus 14.3 ± 1.4 nmol/g; P &amp;lt; 0.01) and ileum (6.4 versus 11.2 ± 0.8 nmol/g; P &amp;lt; 0.001) in W compared with NW pigs. In liver, cysteine concentration was greater in W compared with NW pigs (417 versus 298 ± 33 nmol/g; P &amp;lt; 0.05). Although liver cysteine was greater in W pigs, liver activity of glutamate cysteine ligase (GCL; 2.49 versus 4.15 ± 0.25 nmol γ-GC/(mg protein•min); P &amp;lt; 0.001) and glutathione synthetase (GSS; 1.54 versus 1.92 nmol GSH/(mg protein•min); P &amp;lt; 0.001), enzymes needed for GSH production, were less in W than NW pigs. Immunoblot analysis of the catalytic subunit of GCL (GCLC; P &amp;lt; 0.05) and modifier subunit of GCL (GCLM; P = 0.057) were also lower in W compared with NW pigs, but GSS was not different between groups (P &amp;gt; 0.10). While plasma taurine was lower in W compared with NW pigs (64 versus 128 ± 7 µmol/L, P &amp;lt; 0.001), liver taurine was greater in W compared with NW pigs (4,726 versus 2,250 ± 471 nmol/g; P &amp;lt; 0.01). Despite an increase systemic and liver availability of cysteine, the rate-limiting amino acid for GSH synthesis, small intestine GSH concentrations decline. This suggests that systemic cysteine is not effectively utilized for gut GSH production in pigs after weaning.

402 Awardee Talk: Stress-Induced Dna Methylation Changes and Their Implications in Livestock Production

Abstract It is well known that pre- and post-natal stressors can impact livestock phenotype and performance. However, less is known about the molecular mechanisms responsible for the changes observed in individuals exposed to stress. A proposed mechanism is epigenetic modifications, such as DNA methylation (DNAm). Epigenetic marks are considered a bridge between the environment and genetics because the marks shift in response to environmental stimuli. Stress induced alterations of DNAm can result in changes in gene expression which could be the driver behind altered phenotype. “Omic” technologies have allowed the study of how DNAm patterns change in response to stressors in livestock species. Stressors such as weaning, transportation, and heat stress have altered DNAm patterns. These changes in methylation patterns have been associated with changes in immune function, growth, and behavior. Prenatal stressors have also modified DNAm patterns within the offspring, with some differences persisting later in life. These stress induced DNAm alterations can be transgenerational, potentially affecting livestock productivity and health over multiple generations. Not all alterations are negative; certain stress-induced modifications could allow animals to adapt better to stressors and changing conditions. These marks may indicate exposure of the animal to stress and the possible long-term effects on productivity. There is potential for using methylation patterns as a noninvasive way to monitor stress levels and assess animal welfare. Understanding how the methylome responds to stressors and how it contributes to performance will be beneficial for future selection decisions. More research is needed to identify management practices that might mitigate the negative impacts of stress induced DNAm changes and how the industry can take advantage of the role DNAm has in adapting to stressors and new environments. The epigenome will likely play a critical role in the livestock industry's future as the climate shifts and consumer demands focus more on animal welfare.