Arginine and its metabolites stimulate proliferation, differentiation, and physiological function of porcine trophoblast cells through ß-catenin and mTOR pathways.

Arginine, which is metabolized into ornithine, proline, and nitric oxide, plays an important role in embryonic development. The present study was conducted to investigate the molecular mechanism of arginine in proliferation, differentiation, and physiological function of porcine trophoblast cells (pTr2) through metabolic pathways. The results showed that arginine significantly increased cell viability (P < 0.05). The addition of arginine had a quadratic tendency to increase the content of progesterone (P = 0.06) and protein synthesis rate (P = 0.03), in which the maximum protein synthesis rate was observed at 0.4 mM arginine. Arginine quadratically increased (P < 0.05) the intracellular contents of spermine, spermidine and putrescine, as well as linearly increased (P < 0.05) the intracellular content of NO in a dose-dependent manner. Arginine showed a quadratic tendency to increase the content of putrescine (P = 0.07) and a linear tendency to increase NO content (P = 0.09) in cell supernatant. Moreover, increasing arginine activated (P < 0.05) the mRNA expressions for ARG, ODC, iNOS and PCNA. Furthermore, inhibitors of arginine metabolism (L-NMMA and DFMO) both inhibited cell proliferation, while addition of its metabolites (NO and putrescine) promoted the cell proliferation and cell cycle, the mRNA expressions of PCNA, EGF and IGF-1, and increased (P < 0.05) cellular protein synthesis rate, as well as estradiol and hCG secretion (P < 0.05). In conclusion, our results suggested that arginine could promote cell proliferation and physiological function by regulating the metabolic pathway. Further studies showed that arginine and its metabolites modulate cell function mainly through ß-catenin and mTOR pathways.

Effects of phytase and 25-hydroxyvitamin D3 supplementation on growth performance and bone development in weaned piglets in Ca- and P-deficient dietary.

BACKGROUND: The beneficial function of phytase and 25-hydroxyvitamin D3 (HyD) on the feed utilization rate has been widely investigated. However, studies concerning its influence on weaned piglets largely lag behind. The aim of this study was to investigate the effects of phytase and HyD supplementation on the growth performance and bone development in weaned piglets under dietary Ca and P deficiency. RESULTS: The results showed that dietary Ca and P deficiency decreased (P < 0.05) the content of serum P in 6-10 kg piglets, as well as reducing (P < 0.05) the contents of serum Ca and P, average daily gain (ADG), bone mineral density (BMD), breaking force (BF), bone ash and femur Ca in 10-20 kg piglets. Compared with the control group, the feed-to-gain ratio (F/G) of 6-10 kg piglets in the Phy group was decreased (P < 0.05), whereas the ADG, blood Ca and P, BMD, BF, bone ash, P apparent digestibility, Ca and P retention rate of 10-20 kg piglets were increased (P < 0.05). The contents of serum osteocalcin and HyD in 6-10 kg piglets and ADG were higher than in the control group (P < 0.05), as well as the contents of serum Ca and HyD in 10-20 kg piglets in the HyD treatment group. Supplementation with both Phy and HyD decreased the F/D (P < 0.05) and increased the contents of serum Ca, P and HyD in 6-10 kg piglets as well as enhancing the ADG, BMD, BF, bone ash, femur Ca and P, serum Ca and P, HyD, and the apparent digestibility and retention of Ca and P (P < 0.05) in 10-20 kg piglets. Supplementation with Phy and HyD in Ca- and P-deficient dietary decreased bone resorption, and improved tight arrangement of collagen fibers and oblique fibers in weaned piglets. CONCLUSION: These data indicated that supplementation with both 1500 U kg-1 Phy and 50 µg kg-1 HyD could enhance dietary Ca and P utilization and promote bone development in low Ca and P dietary, and supplementation with both Phy and HyD had a significant synergy effect compared to single supplement. © 2021 Society of Chemical Industry.

Effects of early sub-therapeutic antibiotic administration on body tissue deposition, gut microbiota and metabolite profiles of weaned piglets.

BACKGROUND: This study aimed to evaluate the effects of sub-therapeutic antibiotic (STA) administration and its subsequent withdrawal on the body tissue deposition, gut microbiota, and metabolite profiles of piglets. The piglets in the experimental group were fed with STA (30 mg kg-1 bacitracin methylene disalicylate, 75 mg kg-1 chlortetracycline, 300 mg kg-1 calcium oxytetracycline) for 14 days and the target bodyweight of the withdrawal period was 25 kg. RESULTS: The experiment was divided into two periods: the administration period and the withdrawal period. The results showed that STA did not improve piglets' growth performance during the two periods. Piglets treated with STA had lower body water deposition during the withdrawal period and tended to increase body lipid deposition during the withdrawal period and the whole period in comparison with the piglets in the control group. It was found that STA markedly altered the colonic microbiota and their metabolites in the piglets. Sub-therapeutic antibiotics were initially effective in decreasing the abundance of pathogenic bacteria during the administration period; however, STA could not continue the effect during the withdrawal period, leading to a rebound of pathogenic bacteria such as Alloprevotella and the increased abundance of other pathogenic bacteria like Oscillibacter. Remarkably, STA treatment decreased Blautia abundance. This bacterium plays a potential protective role against obesity. Metabolomic analysis indicated that STA mainly altered amino acid metabolism, lipid metabolism, and carbohydrate metabolism during the two periods. Spearman's correlation analysis showed that the gut microbiota was highly correlated with microbial metabolite changes. CONCLUSION: These results suggest that early STA administration may alter body tissue deposition later in life by reshaping the gut microbiota and their metabolite profiles. © 2022 Society of Chemical Industry.

Meta-analysis of energy intake of growing-finishing pigs in China.

Data from 655 treatments of 116 studies were used in a meta-analysis to determine the daily digestible energy (DE), metabolizable energy (ME) and net energy (NE) intake of Chinese growing-finishing pigs, and to predict feed efficiency responses to change in dietary DE, ME and NE. Three alternative functions (i.e., polynomial, Bridges and asymptotic function) were employed for fitting daily DE, ME or NE intakes to mean body weight. The results showed that the three models from the current study provided reasonable fit (all R2  > 0.83) for the energy intake data. However, under the same energy system, the polynomial function had the smallest Akaike's information criteria (AIC) and residual standard deviation (RSD), followed by Bridges and asymptotic functions. The three model-generated energy intakes of growing pigs were significantly less than that of the Chinese Feeding Standard of Swine, but similar to that of the National Research Council (2012), while the values of finishing pigs were greater than both standards. Compared with those that predict feed efficiency based on DE or ME, the equation with NE as a predictor had the minimized AIC and RSD. It was also found that feed efficiency increased with increasing dietary energy density (DED), but this response varied with pig body weight, and the lighter pigs were more sensitive to DED than heavier pigs.

Valine increases milk fat synthesis in mammary gland of gilts through stimulating AKT/MTOR/SREBP1 pathway†.

Lactating mammary glands are among the most active lipogenic organs and provide a large percentage of bioactive lipids and calories for infant growth. The branched-chain amino acid (BCAA) valine is known to modulate fatty acids synthesis in adipose tissue; however, its effects on fat metabolism and the underlying mechanisms in mammary glands remain to be determined. Valine supplementation during late pregnancy significantly increased the contents of total milk fat, triglyceride, sphingomyelin, and polyunsaturated fatty acids in the colostrum of gilts. Further study in porcine mammary epithelial cells (PMECs) confirmed that valine upregulated the phosphorylation levels of AKT-activated MTOR and subsequently induced the nuclear accumulation of sterol regulatory element binding protein 1 (SREBP1), thus increasing the expression of proteins related to fatty acids synthesis and intracellular triacylglycerol content. Inhibition of AKT/MTOR signaling or silencing of SREBP1 in PMECs downregulates the expression of proteins related to fatty acids synthesis and intracellular triacylglycerol content. Our findings indicated that valine enhanced milk fat synthesis of colostrum in porcine mammary glands via the AKT/MTOR/SREBP1 signaling pathway.

Valine supplementation during late pregnancy in gilts increases colostral protein synthesis through stimulating mTOR signaling pathway in mammary cells.

Mammary gland development during late pregnancy in sows is a major factor affecting the composition of colostrum and milk and the pre-weaning growth of piglets, while valine is essential for protein and nitrogen metabolism in mammary gland of sow. However, the effects of valine and its underlying mechanism on mammary gland development during late pregnancy are still unclear. Here, we hypothesized that dosage of dietary valine during late pregnancy will affect protein synthesis of colostrum in gilts. The results showed that supplementation of valine during late pregnancy significantly increased content of protein (P < 0.01), fat (P = 0.02) and solids-non-fat (P = 0.04) in colostrum. Our in vitro study also confirmed that valine supplementation increased protein synthesis and cell proliferation in porcine mammary epithelial cells (PMEC). Furthermore, these changes were associated with elevated phosphorylation levels of mammalian target of rapamycin (mTOR), and ribosomal protein S6 kinase (S6) and eukaryotic initiation factor 4E-binding protein-1 (4EBP1) in valine-supplemented cells, which could be effectively blocked by the antagonists of mTOR. These findings indicated that valine enhanced mammary gland development and protein synthesis in colostrum via the mTOR signaling pathway. These results, using an in vivo and in vitro model, helped to understand the beneficial effects of dietary valine supplementation on gilts.

Effects of low-molecular-weight chitosan on the growth performance, intestinal morphology, barrier function, cytokine expression and antioxidant system of weaned piglets.

BACKGROUND: Chitosan was used as an alternative to promote the growth of weaned piglets. And low-molecular-weight chitosan (LC) is one of chitosan derivatives and maintain beneficial biological properties of chitoson. The present experiment was carried out to examine the effects of LC on the growth performance, intestinal morphology, barrier function, cytokine expression, and antioxidant system of weaned piglets. RESULTS: A total of 40 piglets weaned at 21 d of age, with average body weight 6.37 ± 0.08 kg, were randomly assigned (5 pens/diet; 4 pigs/pen) to 2 treatments (a basal diet and the basal diet supplemented with 50 mg/kg LC) and were fed for 28 d. Compared with the control group, average daily feed intake (ADFI), and the expression of intestinal barrier protein ZO-1 was increased (P < 0.05) when the piglets fed the diet supplemented with LC. No significant differences were found in average daily gain (ADG, P > 0.05), gain-to-feed ratio (G:F, P > 0.05), the incidence of diarrhea (P > 0.05), or the antioxidant capacity (P > 0.05) between two groups. The expression of IL-1ß and TNF-α in jejunal mucosa were significantly decreased (P < 0.05) in piglets fed the LC-supplemented diet in comparison to the control. CONCLUSION: The results of this study indicate that dietary supplementation with LC at 50 mg/kg was effective for enhancing the growth performance in weaned piglets, improving intestinal barrier function and alleviating intestinal inflammation.

Lactobacillus reuteri LR1 Improved Expression of Genes of Tight Junction Proteins via the MLCK Pathway in IPEC-1 Cells during Infection with Enterotoxigenic Escherichia coli K88.

Intestinal epithelial barrier damage disrupts immune homeostasis and leads to many intestinal disorders. Lactobacillus reuteri strains have probiotic functions in their modulation of the microbiota and immune system in intestines. In this study, the effects of L. reuteri LR1, a new strain isolated from the feces of weaning piglets, on intestinal epithelial barrier damage in IPEC-1 cells caused by challenge with enterotoxigenic Escherichia coli (ETEC) K88 were examined. It was found that L. reuteri LR1, in large part, offset the ETEC K88-induced increase in permeability of IPEC-1 cell monolayers and decreased the adhesion and invasion of the coliform in IPEC-1 cells. In addition, L. reuteri LR1 increased transcript abundance and protein contents of tight junction (TJ) proteins zonula occluden-1 (ZO-1) and occludin in ETEC K88-infected IPEC-1 cells, whereas it had no effects on claudin-1 and F-actin expression. Using colloidal gold immunoelectron microscopy, these effects of L. reuteri LR1 on ZO-1 and occludin content in IPEC-1 cells were confirmed. By using ML-7, a selective inhibitor of myosin light-chain kinase (MLCK), the beneficial effect of L. reuteri LR1 on contents of ZO-1 and occludin was shown to be dependent on the MLCK pathway. In conclusion, L. reuteri LR1 had beneficial effects on epithelial barrier function consistent with increasing ZO-1 and occludin expression via a MLCK-dependent manner in IPEC-1 cells during challenge with ETEC K88.

Effect of Dietary Standardized Ileal Digestible Arginine to Lysine Ratio on Reproductive Performance, Plasma Biochemical Index, and Immunity of Gestating Sows.

The aim of this study was to determine the optimal SID Arg: Lys ratio for maximizing the reproductive performance, immunity and biochemical parameters of sows during gestation, the colostrum composition, and the performance of their offspring. A total of 174 multiparous sows were randomly allocated to five treatment groups varying in dietary SID Arg: Lys ratios (0.91, 1.02, 1.14, 1.25 and 1.38) through modification of the levels of Arg or alanine supplementation (the total level of nitrogen was the same in all treatments). The results showed that increasing the dietary SID Arg: Lys ratio increased the number of piglets born alive (p < 0.05, linear and quadratic). The number of stillborn piglets, the birth weight variation of born alive piglets, the birth interval (p < 0.05, linear and quadratic) and the number of mummies (p < 0.05, quadratic) reduced with increasing the dietary SID Arg: Lys ratio. Broken-line regression analysis indicated that the optimal SID Arg: Lys ratio requirement for gestating sows to maximize the number of piglets born alive was 1.25. The content of non-fat solid, total solid, protein, and energy in colostrum increased linearly and quadratically (p < 0.05) with increasing dietary SID Arg: Lys ratio. Additionally, when increasing the dietary SID Arg: Lys ratio, the concentration of IgA (p < 0.05, quadratic) and IgM (p < 0.05, linear and quadratic) of plasma increased at day 90 of gestation; IgG (p < 0.05, linear and quadratic) concentration increased at day 110 of gestation of sows. The dietary SID Arg: Lys ratio had an increasing effect (p < 0.05, linear and quadratic) on plasma insulin levels at day 90 of gestation. Furthermore, there were increases in plasma concentrations of nitric oxide and ornithine at day 110 of gestation, Arg at day 90 and 110 of gestation (p < 0.05, linear and quadratic) and total protein at day 110 of gestation (p < 0.05, linear) with increasing dietary SID Arg: Lys ratio. The results of our study indicated that increases in the dietary SID Arg: Lys ratio during gestation resulted in an increase in the number of piglets born alive, a decrease in birth intervals, and an improvement in immunity and colostrum composition. The optimal SID Arg: Lys ratio for gestating sows to maximize the number of piglets born alive was 1.25.

Environmentally stable and rapidly polymerized tin-tannin catalytic system hydroxyethyl cellulose hydrogel for wireless wearable sensing.

In recent years, flexible sensors constructed mainly from hydrogels have played an indispensable role in several fields. However, the traditional hydrogel preparation process involves complex and time-consuming steps and the freezing or volatilization of water in the water gel in extreme environments greatly limits the further use of the sensor. Therefore, an ionic conductive hydrogel (SnHTD) was designed, which was composed of tannic acid (TA), metal ions Sn2+, hydroxyethyl cellulose (HEC), and acrylamide (AM) in a deep eutectic solvent (DES) and water binary solvent. It is worth noting that the gel time is shortened to less than 3 min by introducing the Sn-TA redox system. The addition of DES makes the hydrogel have a wide temperature tolerance range (-20 to 60 °C) and the ability to store for a long time (30 days). The introduction of HEC increased the tensile stress of hydrogel from 140.17 kPa to 219.89 kPa. Additionally, the hydrogel also has high conductivity, repeatable adhesion and UV shielding properties. In general, this research opens up a new way for room temperature polymerization of environmentally resistant hydrogel materials and effectively meets the growing demand for wireless wearable sensing.

Lignin hydrogel sensor with anti-dehydration, anti-freezing, and reproducible adhesion prepared based on the room-temperature induction of zinc chloride-lignin redox system.

In recent years, flexible sensors constructed mainly from hydrogels have received increasing attention. However, conventional hydrogels need to be prepared by high-temperature or radiation-induced polymerization reactions, which limits their practical applications due to their suboptimal electrical conductivity and weak mechanical properties. In this paper, using sodium lignosulfonate as the raw material, a dynamic catechol-quinone redox system formed by lignin­zinc ions was constructed to initiate rapid free radical polymerization of acrylamide (AM) monomer at room temperature. In addition, Deep eutectic solvent (DES) can form a strong hydrogen bonding network within the molecules and between the molecules of the hydrogel, resulting in a hydrogel with good tensile properties (hydrogel elongation at break of 727.19 %, breaking strength of 84.09 kPa), and provides the hydrogel with high electrical conductivity, anti-dehydration, anti-freezing, and anti-bacterial properties. Meanwhile, the addition of lignin also improved the adhesion and UV resistance of the hydrogel. This hydrogel assembled into a flexible sensor can sense various small and large amplitude movements such as nodding, smiling, frowning, etc., and has a wide range of applications in flexible sensors.

High mechanical, self-adhesive oxidized guar gum/chitosan hydrogel prepared at room temperature based on a nickel-urushiol catalytic system for wireless wearable sensors.

Recently, sensors constructed on the basis of hydrogel are playing a major role in health detection such as motion detection and breathing monitoring. However, the common hydrogels have poor mechanical properties, insufficient adhesion and complex preparation processes, which hinder the further use of such sensors. In this paper, the conductive hydrogel (P(AA-UH)-OGG-CS/NiCl2) composed of acrylic acid (AA), oxidized guar gum (OGG) and chitosan (CS) was prepared at room temperature through the dynamic redox reaction of nickel chloride (NiCl2) and urushiol (UH). In detail, the reduction group (phenolic hydroxyl) of UH and Ni2+/Ni3+ pair form a semi-quinone/quinone redox dynamic cycle system, allowing the hydrogel to quickly gel at room temperature for 3 min. The catechol group in UH also promotes the hydrogel to have a superior adhesion strength of 25.23 kPa to pig skin and a strong repeated adhesion performance. In addition, the dynamic Schiff base bond created by the interaction of OGG and CS elevated the tensile stress of the hydrogel to 67.54 kPa. After the hydrogel is assembled into the sensor, it has high sensitivity and high stability to different strains, and has great application prospects in the field of actual human health monitoring.

Effects of Dietary Net Energy Concentration on Reproductive Performance, Immune Function, Milk Composition, and Gut Microbiota in Primiparous Lactating Sows.

This study aimed to determine the optimal dietary net energy concentration for the reproductive performance, immune function, milk composition, and gut microbiota of primiparous sows during lactation. Forty primiparous lactating sows (Landrace × Yorkshire) with similar body backfat thicknesses were randomly allocated into five treatment groups and fed diets with different dietary net energy concentrations of 10.05 MJ/kg, 10.47 MJ/kg, 10.89 MJ/kg, 11.30 MJ/kg, and 11.72 MJ/kg. The results showed that there were no differences in the performance of piglets, while there was a decrease in the daily feed intake of sows (p = 0.079, linear) as dietary net energy concentration increased. With the increasing dietary net energy concentration, the plasma insulin levels of sows increased (p < 0.01, linear), the plasma glucose levels tended to increase (p = 0.074, linear), and the blood urea nitrogen levels tended to decrease (p = 0.063, linear). Moreover, the plasma total superoxide dismutase activity of sows increased (p < 0.05, quadratic) and the plasma malondialdehyde content of sows decreased (p < 0.05, quadratic) by increasing the dietary net energy concentration. Interestingly, with the increase in dietary net energy concentration, the plasma immunoglobulin M content of sows increased, the milk immunoglobulin M, immunoglobulin G, immunoglobulin A and the percentage of milk fat increased (p < 0.05, linear), and the milk secretory immunoglobulin A content also increased (p < 0.05, linear and quadratic). The milk immunoglobulins and milk fat content of sows fed with net energy concentration of 11.72 MJ/kg were highest. Moreover, there were significant differences in the α-diversity, ß-diversity, and relative abundance of gut microbiota in sows fed with different dietary net energy concentrations. At the phylum level, Spirochaetota and Bacteroidota in the gut microbiota of sows were mainly affected by increasing the dietary net energy concentration. Furthermore, the correlation analysis showed that milk immunoglobulin content had a significant negative correlation with the relative abundance of Bacteroidota, and plasma malondialdehyde content also had a significant negative correlation with the relative abundance of Spirochaetota. In summary, these results suggest that increasing the dietary net energy concentration to 11.72 MJ/kg can increase immunological substances in milk, improve milk quality, and alter the composition of gut microbiota in primiparous lactating sows.

Maternal resveratrol improves the intestinal health and weight gain of suckling piglets during high summer temperatures: The involvement of exosome-derived microRNAs and immunoglobin in colostrum.

Previous studies have shown that maternal resveratrol improved growth performance and altered the microbial composition of suckling piglets under hot summer conditions. However, it remains unclear how maternal resveratrol improves growth performance of suckling piglets during high summer temperatures. A total of 20 sows (Landrace × Large White; three parity) were randomly assigned to 2 groups (with or without 300 mg/kg resveratrol) from d 75 of gestation to d 21 of lactation during high ambient temperatures (from 27 to 30 °C). The results showed that maternal resveratrol supplementation increased total daily weight gain of piglets under hot summer conditions, which is consistent with previous studies. Furthermore, we found that maternal resveratrol improved the intestinal morphology and intestinal epithelial proliferation in suckling piglets. Dietary resveratrol supplementation affected the characteristics of exosome-derived microRNAs (miRNAs) in sow colostrum, as well as the genes targeted by differentially produced miRNAs. MiRNAs are concentrated in the tight junction pathway. As a result, the expression of intestinal tight junction proteins was increased in suckling piglets (P < 0.05). Notably, maternal resveratrol increased the intestinal secretory immunoglobulin A (sIgA) levels of suckling piglets via colostrum immunoglobin (P < 0.05), which could increase the abundance of beneficial microbiota to further increase the concentration of short chain fatty acids (SCFA) in suckling piglets' intestine (P < 0.05). Finally, our correlation analysis further demonstrated the positive associations between significantly differential intestinal microbiota, intestinal sIgA production and SCFA concentrations, as well as the positive relation between total daily weight gain and intestinal health of suckling piglets. Taken together, our findings suggested that maternal resveratrol could promote intestinal health to improve piglet growth during high summer temperatures, which might be associated with the immunoglobin and exosome-derived miRNAs in sows' colostrum.

Effect of Miscellaneous Meals Replacing Soybean Meal in Feed on Growth Performance, Serum Biochemical Parameters, and Microbiota Composition of 25-50 kg Growing Pigs.

The present study aims to determine the effect of miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower meal) replacing soybean meal in feed on growth performance, apparent digestibility of nutrients, serum biochemical parameters, serum free amino acid content, microbiota composition and SCFAs content in growing pigs (25-50 kg). A total of 72 (Duroc × Landrace × Yorkshire) growing pigs with initial weights of 25.79 ± 0.23 kg were randomly divided into three treatments. The pigs were fed corn-soybean meal (CON), corn-soybean-miscellaneous meals (CSM), and corn-miscellaneous meals (CMM). Each treatment included six replicates with four pigs per pen (n = 24, 12 barrows and 12 gilts). Soybean meal accounted for 22.10% of the basal diet in the CON group. In the CSM group, miscellaneous meals partially replaced soybean meal with a mixture of 4.50% rapeseed meal, 3.98% cottonseed meal, and 4.50% sunflower meal. In the CMM group, miscellaneous meals entirely replaced soybean meal with a mixture of 8.50% rapeseed meal, 8.62% cottonseed meal, and 8.5% sunflower. The results showed that compared with the CON, the CSM and CMM groups significantly improved the average daily gain (ADG) of growing pigs during the 25-50 kg stage (p < 0.05) but had no effects on average daily feed intake (ADFI) and average daily feed intake/average daily gain (F/G) (p > 0.05). Moreover, the CMM group significantly reduced nutrient apparent digestibility of gross energy compared with the CON group. The serum biochemical parameters results showed that the CSM group significantly improved the contents of total protein (TP) compared with the CON group (p < 0.05). The CMM group significantly improved the contents of total protein (TP), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) compared with the CON group in serum (p < 0.05). In comparison with the CON group, the CMM group also significantly improved lysine (Lys), threonine (Thr), valine (Val), isoleucine (Ile), leucine (Leu), phenylalanine (Phe), arginine (Arg), and citrulline (Cit) levels in serum (p < 0.05). However, the CMM group significantly decreased non-essential amino acid content glycine (Gly) in serum compared with CON (p < 0.05), while compared with the CON group, the CSM and CMM groups had no significant effects on the relative abundance, the alpha-diversity, or the beta-diversity of fecal microbiota. Moreover, compared with the CON group, the CSM group significantly increased butyric acid and valeric acid contents of short-chain fatty acids (SCFAs) in feces (p < 0.05). In contrast to the CON group, the CMM group significantly reduced the contents of SCFAs in feces, including acetic acid, propionic acid, and isobutyric acid (p < 0.05). Collectively, the results of the present study indicate that miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower meal) can partially replace the soybean meal and significantly improve the growth performance of growing pigs during the 25-50 kg stage. Thus, miscellaneous meals are a suitable protein source as basal diets to replace soybean meals for 25-50 kg growing pigs. These results can be helpful to further develop miscellaneous meals as a functional alternative feed ingredient to soybean meal.

Effect of mixed meal replacement of soybean meal on growth performance, nutrient apparent digestibility, and gut microbiota of finishing pigs.

Introduction: This study was carried out to investigate the effects of mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacement soybean meal on growth performance, nutrient apparent digestibility, serum inflammatory factors and immunoglobulins, serum biochemical parameters, intestinal permeability, short-chain fatty acid content, and gut microbiota of finishing pigs. Methods: A total of 54 pigs with an average initial weight of 97.60 ± 0.30 kg were selected and randomly divided into 3 groups according to their initial weight, with 6 replicates in each group and 3 pigs in each replicate. The trial period was 26 days. The groups were as follows: control group (CON), fed corn-soybean meal type basal diet; Corn-soybean-mixed meal group (CSM), fed corn-soybean meal-mixed meal diet with a ratio of rapeseed meal, cotton meal, and sunflower meal of 1:1:1 to replace 9.06% soybean meal in the basal diet; Corn-mixed meal group (CMM), fed a corn-mixed meal diet with a ratio of Rapeseed meal, Cotton meal and Sunflower meal of 1:1:1 to replace soybean meal in the basal diet completely. The crude protein level of the three diets was maintained at 12.5%. Results: Our findings revealed no significant impact of replacing soybean meal with the mixed meal (rapeseed meal, cotton meal, and sunflower meal) on the ADG (Average daily gain), ADFI (Average daily feed intake), and F/G (Feed gain ratio) (P > 0.05), or crude protein, crude fat, and gross energy (P > 0.05) in the diet of finishing pigs. Compared with the CON group, the serum interleukin 6 (IL-6) and interleukin 10 (IL-10) concentrations were significantly decreased in the CMM group (P < 0.05). However, there is no significant effect of the mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacing soybean meal in the diet on the serum interleukin 1ß (IL-1ß), interleukin 8 (IL-8), tumor necrosis factor-alpha (TNF-α), immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations (P > 0.05). Concordantly, there is no significant effect of mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacing soybean meal in the diet on the serum antioxidant capacity, such as total antioxidant capacity (T-AOC), catalase (CAT), and malondialdehyde (MDA) levels of finishing pigs. Moreover, compared with the CON group, serum low-density lipoprotein (LDL-C) levels were significantly lower in the CSM group (P < 0.05) and their total bilirubin (TBIL) levels were significantly lower in the CMM group (P < 0.05). There is not a significant effect on serum D-lactate and diamine oxidase (DAO) concentrations (P > 0.05). The next section of the survey showed that the replacement of soybean meal with a mixed meal (rapeseed meal, cotton meal, and sunflower meal) in the diet did not significantly influence the acetic acid, propionic acid, butyric acid, valeric acid, isobutyric acid, and isovaleric acid in the colon contents (P > 0.05). Furthermore, compared with the CON group, the CMM group diet significantly increased the abundance of Actinobacteria at the phylum level (P < 0.05), U_Actinobacteria at the class level (P < 0.05), and U_Bacteria at the class level (P < 0.05). The result also showed that the CMM group significantly reduced the abundance of Oscillospirales at the order level (P < 0.05) and Streptococcaceae at the family level (P < 0.05) compared with the CON group. The Spearman correlation analysis depicted a statistically significant positive correlation identified at the class level between the relative abundance of U_Bacteria and the serum T. BILI concentrations (P < 0.05). Moreover, a significant negative correlation was detected at the order level between the relative abundance of Oscillospirales and the levels of acetic and propionic acids in the colonic contents (P < 0.05). Additionally, there was a significant positive correlation between the serum concentrations of IL-6 and IL-10 and the relative abundance of the family Streptococcaceae (P < 0.05). Discussion: This study demonstrated that the mixed meal (rapeseed meal, cotton meal, and sunflower meal) as a substitute for soybean meal in the diet had no significant negative effects on the growth performance, nutrient apparent digestibility, serum immunoglobulins, serum antioxidant capacity, intestinal permeability, short-chain fatty acid content, and diversity of gut microbiota of finishing pigs. These results can help develop further mixed meals (rapeseed meal, cotton meal, and sunflower meal) as a functional alternative feed ingredient for soybean meals in pig diets.

Effects of Vitamin A on Growth Performance, Antioxidants, Gut Inflammation, and Microbes in Weaned Piglets.

Piglet weaning is an important stage in production where changes in the environment and diet can cause problems such as intestinal inflammation and diarrhea. Vitamin A is an essential nutrient for human and animal growth and has immunomodulatory and inflammatory effects. A large body of literature has previously reported on the use of vitamin A in piglet production, so our experiment added different concentrations of vitamin A (0, 1100, 2200, 4400, 8800, and 17,600 IU/kg) to weaned piglet diets to study the effects of different doses on growth performance, intestinal barrier, inflammation, and flora in weaned piglets. We selected 4400 IU/kg as the optimum concentration of vitamin A in relation to average daily weight gain, feed intake, feed-to-weight ratio, and diarrhea rate, and subsequently tested the inflammatory factors, immunoglobulin content, antioxidant levels, and intestinal flora of weaned piglets. Results: We observed that the diarrhea rate of weaned piglets was significantly lower after the addition of 4400 IU/kg of vitamin A to the diet (p < 0.05). A control group and a 4400 IU/kg VA group were selected for subsequent experiments. We found that after the addition of vitamin A, the serum CAT level of weaned piglets increased significantly, the expression of Claudin-1 in the jejunum and ileum increased significantly, the expression of Occludin gene in the jejunum increased significantly, the expression of IL-5 and IL-10 in the ileum increased significantly (p < 0.05), and the expression of IL-4, IL-5, and IL-10 in the ileum increased significantly (p < 0.05). Meanwhile, in the colonic flora of vitamin A-added weaned piglets, the relative abundance of Actinobacteria and Erysipelotrichales decreased significantly, while the relative abundance of Bacteroidales increased significantly (p < 0.05). The results of this study indicated that vitamin A at 4400 IU/kg reduces diarrhea in weaned piglets by increasing antioxidant levels, increasing intestinal tight junction protein gene expression, and regulating colonic gut microbiota.

Glutamine protects intestinal immunity through microbial metabolites rather than microbiota.

Glutamine has anti-inflammatory properties as well as the ability to maintain the integrity of the intestinal barrier. In our previous study, we found that 1.0% glutamine promoted SIgA (secretory immunoglobulin A) synthesis in the gut via both T cell-dependent and non-dependent processes, as well as via the intestinal microbiota. The purpose of this study was to investigate whether the intestinal microbiota or microbial metabolites regulate SIgA synthesis. In the mouse model, supplementation with 1.0% glutamine had no significant effect on the intestinal microbiota, but KEGG function prediction showed the difference on microbiota metabolites. Therefore, in this study, untargeted metabolomics techniques were used to detect and analyze the metabolic changes of glutamine in intestinal luminal contents. Metabolomics showed that in the positive ion (POS) mode, a total of 1446 metabolic differentials (VIP ≥ 1, P < 0.05, FC ≥ 2 or FC ≤ 0.5) were annotated in samples treated with glutamine-supplemented group compared to control group, of which 922 were up-regulated and 524 down-regulated. In the negative ion (NEG) mode, 370 differential metabolites (VIP ≥ 1, P < 0.05, FC ≥ 2 or FC ≤ 0.5) were screened, of which 220 were up-regulated and 150 down-regulated. These differential metabolites mainly include bile secretion synthesis, ABC transporters, diterpenoids and other secondary metabolites. KEGG analysis showed that propionic acid metabolism, TCA cycle, endoplasmic reticulum protein processing, nitrogen metabolism and other metabolic pathways were active. The above metabolic pathways and differential metabolites have positive effects on intestinal development and intestinal immunity, and combined with our previous studies, we conclude that glutamine supplementation can may maintain intestinal homeostasis and improving intestinal immunity through intestinal microbial metabolites.

Taurine alleviates oxidative stress in porcine mammary epithelial cells by stimulating the Nrf2-MAPK signaling pathway.

The high incidence of oxidative stress in sows during late gestation and lactation affects mammary gland health, milk yield, and milk quality. Recently, we found that supplementing maternal diets with 1% taurine improved antioxidant capability and enhanced growth performance in offspring; however, the mechanisms underlying these are unknown. This study aimed to investigate the cytoprotective effects and the mechanism of taurine in mitigating oxidative stress in porcine mammary epithelial cells (PMECs). PMECs were pretreated with 0-2.0 mM taurine for 12 h and then subjected to oxidative injury with 500 µM hydrogen peroxide (H2O2). Pretreatment with taurine attenuated decreased cell viability, enhanced superoxide dismutase, and reduced the intracellular reactive oxygen species accumulation after H2O2 exposure. Taurine also prevented H2O2-induced endoplasmic reticulum stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) was essential to the cytoprotective effects of taurine on PMECs, as Nrf2 knockdown significantly inhibited taurine-induced cytoprotection against oxidative stress. Moreover, we confirmed that Nrf2 induction by taurine was mediated through the inactivation of the p38/MAPK pathway. Overall, taurine supplementation has beneficial effects on redox balance regulation and may protect against oxidative stress in lactating animals.

Effect of Miscellaneous Meal Replacements for Soybean Meal on Growth Performance, Serum Biochemical Parameters, and Gut Microbiota of 50-75 kg Growing Pigs.

This study was carried out to investigate the effects of miscellaneous meal (rapeseed meal, cottonseed meal, and sunflower seed meal) as a replacement for soybean meal on growth performance, apparent nutrient digestibility, serum biochemical parameters, serum free amino acid contents, and gut microbiota of 50-75 kg growing pigs. A total of 54 healthy growing pigs (Duroc × Landrace × Yorkshire) with initial body weights (BWs) of 50.64 ± 2.09 kg were randomly divided into three treatment groups, which included the corn-soybean meal group (CON), corn-soybean-miscellaneous meal group (CSM), and corn-miscellaneous meal group (CM). Each treatment included six replicates with three pigs in each replicate. Dietary protein levels were maintained at 15% in all three treatment groups. Additional rapeseed meals, cottonseed meals, and sunflower seed meals were added to the CSM group's meals to partially replace the 10.99% soybean meal in the CON group in a 1:1:1 ratio. Pigs in the CM group were fed a diet with a mixture of miscellaneous meals (7.69% rapeseed meal, 7.69% cottonseed meal, and 7.68% sunflower seed meal) to totally replace soybean meal. Our findings revealed that there was no significant impact of replacing soybean meal with miscellaneous meal on the ADG (average daily gain), ADFI (average daily feed intake), or F/G (feed-to-gain ratio) (p > 0.05) of growing pigs weighing 50-75 kg, nor on the crude protein, crude fat, or gross energy (p > 0.05) of the diet. On the other hand, compared to the CON group, the CM group exhibited significantly elevated serum alanine aminotransferase (ALT) and triglyceride (TG) levels (p < 0.05), while urea levels were significantly reduced (p < 0.05). No significant effect was observed on the serum free amino acid contents (p > 0.05) following the substitution of soybean meal with miscellaneous meal. A t-test analysis indicated that compared with the CON group, the CM group exhibited a significantly diminished abundance of Euryachaeota at the phylum level and augmented abundance of Desulfobacterota at the genus level. This study demonstrated that the miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower seed meal) as a substitute for soybean meal in the diet had no significant negative effects on the growth performance, apparent nutrient digestibility, serum amino acid content, or diversity of fecal microbiota in 50-75 kg growing pigs. These results can be helpful in developing further miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower seed meal) as functional alternative feed ingredients to soybean meal in pig diets.