Silybin Alleviated Hepatic Injury by Regulating Redox Balance, Inflammatory Response, and Mitochondrial Function in Weaned Piglets under Paraquat-Induced Oxidative Stress.

Silybin (Si) is the main element of silymarin isolated from the seeds of Silybum marianum L. Gaernt., which has superior antioxidant properties. However, the protective role of Si in maintaining liver health under oxidative stress remains ambiguous. This study aimed to investigate the underlying mechanism of the beneficial effect of dietary Si against hepatic oxidative injury induced by paraquat (PQ) in weaned piglets. A total of 24 piglets were randomly allocated to four treatments with six replicates per treatment and 1 piglet per replicate: the control group; Si group; PQ group; and Si + PQ group. Piglets in the control group and PQ group were given a basal diet, while piglets in the Si and Si + PQ groups were given a Si-supplemented diet. On the 18th day, the pigs in the PQ treatment group received an intraperitoneal injection of PQ, and the others were intraperitoneally injected with the same volume of saline. All piglets were sacrificed on day 21 for plasma and liver sample collection. The results showed that dietary Si supplementation mitigated PQ-induced liver damage, as proven by the reduction in liver pathological changes and plasma activity of alanine transaminase and aspartate transaminase. Si also improved superoxide dismutase and glutathione peroxidase activities and total antioxidant capacity, as well as decreased malondialdehyde and hydrogen peroxide concentration in the liver, which were closely related to the activation of the nuclear factor-erythroid 2-related factor 2 signaling pathway. Meanwhile, Si reduced tumor necrosis factor-α and interleukin-8 production and their transcript levels as well as abrogated the overactivation of nuclear factor-κB induced by PQ. Importantly, Si improved mitochondrial function by maintaining mitochondrial energetics and mitochondrial dynamics, which was indicated by the elevated activity of mitochondrial complexes I and V and adenosine triphosphate content, decreased expression of dynamin 1 protein, and increased expression of mitofusin 2 protein. Moreover, Si inhibited excessive hepatic apoptosis by regulating the B-cell lymphoma-2 (Bcl-2)/Bcl-2-associated-X-protein signaling pathway. Taken together, these results indicated that Si potentially mitigated PQ-induced hepatic oxidative insults by improving antioxidant capacity and mitochondrial function and inhibiting inflammation and cell apoptosis in weaned piglets.

Porous Zinc Oxide and Plant Polyphenols as a Replacement for High-Dose Zinc Oxide on Growth Performance, Diarrhea Incidence, Intestinal Morphology and Microbial Diversity of Weaned Piglets.

The aim of this experiment is to evaluate the effects of adding porous zinc oxide, plant polyphenols, and their combination to diets without antibiotics and high-dose zinc oxide on the growth performance, diarrhea incidence, intestinal morphology, and microbial diversity of weaned piglets. A total of 150 Duroc × Landrace × Large White weaned piglets were allocated to one of five diets in a randomized complete block design with six replicates and five piglets per replicate. The experimental period was 42 d, divided into two feeding stages: pre-starter (0-14 d) and starter (14-42 d). In the pre-starter stage, the negative control group (NC) was fed a basal diet, the positive control group (PC) was fed a basal diet with 2000 mg/kg of zinc oxide, the porous zinc oxide group (PZ) was fed a basal diet with 500 mg/kg of porous zinc oxide, the plant polyphenol group (PP) was fed a basal diet with 1500 mg/kg of plant polyphenols, and the combination group (PZ + PP) was fed a basal diet with 500 mg/kg of porous zinc oxide and 1500 mg/kg of plant polyphenols. In the starter stage, the NC, PC, and PZ groups were fed a basal diet, while the PP and PZ + PP groups were fed a basal diet with 1000 mg/kg of plant polyphenols. The results showed that, (1) compared with the PZ group, adding plant polyphenols to the diet showed a trend of increasing the ADFI of weaned piglets from 14 to 28 d (p = 0.099). From days 28 to 42 and days 0 to 42, porous zinc oxide and the combination of porous zinc oxide and plant polyphenols added to the control diet improved the FCR to the level observed in pigs fed the PC diet. (2) Dietary PZ + PP tended to increase the jejunal villus height (VH) of weaned piglets (p = 0.055), and significantly increased the villus-height-to-crypt-depth ratio compared to the NC group (p < 0.05). (3) Compared with the NC group, PZ supplementation decreased the relative abundance of Firmicutes and increased the relative abundance of Bacteroidetes, and the relative abundance of Lactobacillus in the PZ and PZ + PP groups were both increased. In conclusion, porous zinc oxide and plant polyphenols may have synergistic effects in modulating intestinal health in weaned piglets and be a potential alternative to high-dose zinc oxide.

Pyrroloquinoline quinone regulates glycolipid metabolism in the jejunum via inhibiting AMPK phosphorylation of weaned pigs.

Maintenance of intestinal metabolic function is important for optimal growth performance in post-weaning pigs. This study aimed to evaluate the effect of pyrroloquinoline quinone (PQQ) on maintaining intestinal glycolipid metabolism in weaned pigs. Seventy-two Duroc × Landrace × Yorkshire crossbred pigs were divided into two groups: pigs fed a basal diet (CTRL group) and pigs fed a basal diet supplemented with 3.0 mg kg-1 PQQ (PQQ group). On d 14, serum was harvested from six pigs per group and the pigs were slaughtered to sample jejunal tissue. Compared with the CTRL group, pigs in the PQQ group had increased average daily gain (P < 0.05), decreased feed : gain (P < 0.05) and tended to have a reduced diarrhea ratio (P = 0.057). Jejunal villus height and villus height/crypt depth ratio were increased, and the crypt depth was decreased in the PQQ group (P < 0.01). The proteomics results showed that PQQ supplementation acted on three metabolic pathways, type I diabetes mellitus, the pancreatic secretion pathway and immune-related signalling. Compared with the CTRL group, PQQ supplementation increased (P < 0.05) serum insulin and jejunal mucosal pyruvate, triglyceride, total cholesterol and low-density lipoprotein cholesterol in the pigs. Jejunal mucosal lactic dehydrogenase and high-density lipoprotein cholesterol levels in the pigs were decreased by PQQ supplementation (P < 0.05). In addition, PQQ supplementation reduced glucose transporter 5 and phosphorylated-AMP-activated protein kinase expression in the jejunal mucosa of the pigs (P < 0.05). In conclusion, dietary supplementation with PQQ improved the growth performance and jejunal morphology and regulated glycolipid metabolism via inhibiting AMPK phosphorylation in weaned pigs.

Pyrroloquinoline Quinone Regulates Enteric Neurochemical Plasticity of Weaned Rats Challenged With Lipopolysaccharide.

The enteric nervous system (ENS) is important for the intestinal barrier to defend and regulate inflammation in the intestine. The aim of this study was to investigate the effect of pyrroloquinoline quinone (PQQ) on regulating neuropeptide secretion by ENS neurons of rats challenged with lipopolysaccharide (LPS) to create enteritis. Thirty Sprague Dawley rats were divided into five groups, namely, basal (CTRL), basal plus LPS challenge (LPS), basal with 2.5 mg/kg b.w./day of PQQ plus challenge with LPS (PQQ 2.5), basal with 5.0 mg/kg b.w./day PQQ plus challenge with LPS (PQQ 5), and basal with 10.0 mg/kg b.w./day PQQ plus challenge with LPS (PQQ 10). After treatment with basal diet or PQQ for 14 days, rats were challenged with LPS except for the CTRL group. Rats were euthanized 6 h after the LPS challenge. Rats showed an increased average daily gain in PQQ treatment groups (P < 0.05). Compared with the LPS group, PQQ 5 and PQQ 10 rats showed increased villus height and villus height/crypt depth of jejunum (P < 0.05). In PQQ treatment groups, concentrations of IL-1ß and TNF-α in serum and intestine of rats were decreased, and IL-10 concentration was increased in serum compared with the LPS group (P < 0.05). Compared with the LPS group, the concentration of neuropeptide Y (NPY), nerve growth factor (NGF), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), and brain-derived neurotropic factor (BDNF) in serum were decreased in PQQ treatment groups (P < 0.05). Compared with the LPS group, ileal mRNA levels of BDNF, NPY, and NGF were decreased in PQQ treatment groups (P < 0.05). Jejunal concentrations of SP, CGRP, VIP, BDNF, NPY, and NGF were decreased in PQQ treatment groups compared with the LPS group (P < 0.05). Compared with the LPS group, phosphor-protein kinase B (p-Akt)/Akt levels in jejunum and colon were decreased in PQQ treatment groups (P < 0.05). In conclusion, daily treatment with PQQ improved daily gain, jejunal morphology, immune responses. PQQ-regulated enteric neurochemical plasticity of ENS via the Akt signaling pathway of weaned rats suffering from enteritis.

Effect of maternal dietary starch-to-fat ratio and daily energy intake during late pregnancy on the performance and lipid metabolism of primiparous sows and newborn piglets.

The present study evaluated the effects of maternal dietary energy intake and starch-to-fat ratio during late gestation on the performance and lipid metabolism of sows and their offspring. On day 84 of gestation, 80 Landrace × Yorkshire primiparous sows were assigned to 2 × 2 factorial arrangements according to body weight following a randomized complete block design. The factors were daily energy intake (8,375 kcal ME/d [CE] vs. 9,600 kcal ME/d [HE]) and dietary starch-to-fat ratio (10:1 [CR] vs. 15:1 [HR]). All sows were fed one of four diets from day 85 of gestation until farrowing. Data were analyzed using the GLM procedure in SPSS. High energy intake increased the body weight of sows on day 110 of gestation (P = 0.031) as well as the weight of piglets at birth (P = 0.018). Increased energy intake elevated the plasma triglyceride concentrations in sows (P = 0.027) and piglets (P = 0.044). Maternal high energy intake altered the liver metabolome of newborn piglets in terms of metabolites related to carbohydrate and linoleic acid metabolism. Moreover, maternal high energy intake increased hepatic total cholesterol (P = 0.023) and triglyceride (P = 0.026) concentration in newborn piglets. Furthermore, maternal high energy intake significantly increased the transcript abundance of fatty acid synthase (FAS; P = 0.001) and protein abundance of phosphorylated protein kinase B (P =0.001) in the liver of newborn piglets. A high starch-to-fat ratio reduced low-density lipoprotein cholesterol (LDL-C) concentration in the plasma of sows (P = 0.044) and newborn piglets (P = 0.048) as well as in the liver of newborn piglets (P = 0.015). Furthermore, maternal high starch-to-fat ratio increased the transcript abundances of FAS (P = 0.004) in newborn piglets. In conclusion, high daily energy intake of sows increased the birth weight of newborn piglets. Moreover, maternal high daily energy intake and high dietary starch-to-fat ratio improved the lipid metabolism of newborn piglets.

Given the growing concern regarding nutrition during gestation, the present study was designed to investigate the effects of energy on the reproductive performance and lipid metabolism of primiparous sows. Fat and starch are common dietary energy sources. Late gestation is a critical period for both sows and piglets. During late gestation, primiparous sows were administered one of the four dietary treatments (two daily energy intakes × two dietary starch-to-fat ratios). High energy intake increased the body weight of sows and birth weight of piglets. Additionally, increased energy intake elevated the plasma triglyceride concentration of sows and piglets. Moreover, maternal nutrition affected the hepatic lipid metabolism of newborn piglets. Therefore, offspring metabolism can be regulated through maternal diet. In conclusion, high daily energy intake of sows increased the birth weight of newborn piglets. Moreover, maternal high daily energy intake and high dietary starch-to-fat ratio improved the lipid metabolism of newborn piglets.

Effects of Weaning Age at 21 and 28 Days on Growth Performance, Intestinal Morphology and Redox Status in Piglets.

The study objective was to assess effects of different weaning ages on growth performance, intestinal morphology and redox status in Duroc × Landrace × Large White piglets (n = 96) fed diets without antibiotic growth promoters. Piglets were selected from 24 litters based on similar body weight at 14 d of age. All piglets were allocated to two groups in a completely random design with six replicates and eight pigs per replicate (four barrows and four gilts), which were weaned at 21 (n = 48; BW = 6.87 ± 0.33 kg) and 28 (n = 48; BW = 8.49 ± 0.41 kg) days of age. After weaning, pigs were fed a corn-soybean meal-based diet. Average daily gain (ADG), average daily feed intake (ADFI), feed conversion (F:G), diarrhea incidence, gastrointestinal pH, intestinal morphology and redox status were determined. Pigs weaned at 28 d displayed increased ADG from d 8 to 14 (p < 0.01) compared with pigs weaned at 21 d. Pigs weaned at 28 d had a higher ADFI from d 0 to 7 (p < 0.01), d 8 to 14 (p < 0.01), d 15 to 28 (p < 0.05) and during the entire experimental period (p < 0.01) compared with pigs weaned at 21 d. Pigs weaned at 21 d had an improved F:G from d 15 to 28 (p < 0.05) compared with pigs weaned at 28 d. Pigs weaned at 28 d had decreased diarrhea incidence from d 8 to 14 (p < 0.01) and the entire experimental period (p < 0.01) compared with pigs weaned at 21 d. On d 28, the pH of the stomach contents in pigs weaned at 21 d was significantly higher compared with pigs weaned at 28 d (p < 0.01). On d 14, the morphology of the duodenum, jejunum and ileum in pigs weaned at 28 d was improved compared with pigs weaned at 21 d. During the experiment period, the antioxidant abilities of pigs weaned at 28 d of the heart, liver, kidney, intestinal and serum were better than pigs weaned at 21 d. In conclusion, intestinal morphology, pH of the stomach and antioxidant status of pigs weaned at 28 d were better than pigs weaned at 21 d. These factors supported better growth performance and decreased diarrhea incidence.

Effects of Diet Supplemented with Excess Pyrroloquinoline Quinone Disodium on Growth Performance, Blood Parameters and Redox Status in Weaned Pigs.

The research was implemented to assess the safety of feeding excess of pyrroloquinoline quinone disodium (PQQ·Na2) to 108 Duroc × Landrace × Large White weaned pigs (BW = 8.38 ± 0.47 kg). Pigs were weaned at 28 d and randomly distributed to one of three diets with six replicates and six pigs per replicate (three males and three females). Pigs in the control group were fed a corn-soybean meal-based diet (without growth promoter) while the two experimental diets were supplied with 7.5 and 75.0 mg/kg PQQ·Na2, respectively. Average daily gain (ADG), average daily feed intake (ADFI), feed conversion (F:G), diarrhea incidence, hematology, serum biochemistry, organ index and general health were determined. Diets supplementation with 7.5 mg/kg PQQ·Na2 in weaned pigs could increase ADG during the entire experimental period (p < 0.05). And there was a tendency to decrease F:G (p = 0.063). The F:G of weaned pigs fed 7.5 and 75.0 mg/kg PQQ·Na2 supplemented diets was decreased by 9.83% and 8.67%, respectively, compared to the control group. Moreover, pigs had reduced diarrhea incidence (p < 0.01) when supplemented with PQQ·Na2. No differences were observed between pigs supplemented with 0.0, 7.5 and 75.0 mg/kg PQQ·Na2 diets on hematological and serum biochemical parameters as well as histological assessment of heart, liver, spleen, lung and kidney. At day 14, pigs had increased activity of glutathione peroxidase (GSH-Px) (p < 0.05), catalase (CAT) (p < 0.05) and total antioxidant capacity (T-AOC) (p < 0.05), and the serum concentration of malondialdehyde (MDA) was decreased (p < 0.01) with PQQ·Na2 supplementation. At day 28, pigs had increased activities of total superoxide dismutase (T-SOD) (p < 0.01), GSH-Px (p < 0.01), CAT (p < 0.05) and T-AOC (p < 0.01), and serum concentration of MDA was lower (p < 0.01) with PQQ·Na2 supplementation. In conclusion, PQQ·Na2 can improve weaned pigs growth performance and serum antioxidant status. Meanwhile high PQQ·Na2 inclusion of 75.0 mg/kg does not appear to result in harmful effects on growth performance of pigs.

Pyrroloquinoline Quinone Alleviates Jejunal Mucosal Barrier Function Damage and Regulates Colonic Microbiota in Piglets Challenged With Enterotoxigenic Escherichia coli.

This study aimed to evaluate the effect of dietary supplementation with pyrroloquinoline quinone (PQQ) on gut inflammation and microbiota dysbiosis induced by enterotoxigenic Escherichia coli (ETEC). Twenty Duroc × Landrace × Yorkshire crossbred barrows were assigned to four groups: two E. coli K88 challenge groups and two non-challenge groups, each provided a basal diet supplemented with 0 or 3 mg/kg PQQ. On day 14, piglets were challenged with 10 mL 1 × 109 CFU/mL of E. coli K88 or PBS for 48 h. The villus height (VH) and villus height/crypt depth (VCR) ratio of the E. coli K88-challenged group supplemented with PQQ was significantly reduced than in the non-supplemented challenge group (P < 0.05), while levels of jejunal zonula occludens-3 (ZO-3), diamine oxidase, secretory immunoglobulin A (SIgA), interleukin-10 (IL-10), and IL-22 proteins were higher (P < 0.05), as were the activities of glutathione peroxidase, total superoxide dismutase, and total antioxidant capability (P < 0.05). Moreover, PQQ supplementation alleviated an increase in levels of mucosal inflammatory cytokines and reduced the activity of nuclear factor-kappa B (NF-κB) pathway by E. coli K88 (P < 0.05). Gene sequencing of 16S rRNA showed dietary supplementation with PQQ in E. coli K88-challenged piglets attenuated a decrease in Lactobacillus count and butyrate, isobutyrate level, and an increase in Ruminococcus and Intestinibacter counts, all of which were observed in non-supplemented, challenge-group piglets. These results suggest that dietary supplementation with PQQ can effectively alleviate jejunal mucosal inflammatory injury by inhibiting NF-κB pathways and regulating the imbalance of colonic microbiota in piglets challenged with E. coli K88.

Effects of dietary fiber content and different fiber-rich ingredients on endogenous loss of fat and fatty acids in growing pigs.

BACKGROUND: Determination of the endogenous loss of fat (ELF) is used to adjust for the estimation of true total tract digestibility (TTTD) of fat in diets and ingredients. Any factor which affected ELF may further affect the digestibility of fat, including sources and concentrations of fat and fiber in the diet. There are some reports of determining the ELF using regression methods based on different levels of fat intake, while reports on effects of dietary fiber content and different fiber-rich ingredients in pig diets on ELF are very limited. Therefore, the objective of this study was to determine the effects of dietary fiber content and different fiber-rich ingredients on endogenous losses of fat and fatty acids at the end of ileum and throughout the entire intestinal tract in growing pigs. METHODS: In Exp. 1, the effect of fiber content on endogenous loss of fat was determined using six growing pigs (Duroc × Landrace × Yorkshire; 27.6 ± 2.4 kg), fitted with a T-cannula at the end of ileum. The experimental design was a 6 × 6 complete Latin square design with six periods of feeding and six diets. The six experimental fat-free diets were formulated to include graded levels of neutral detergent fiber (NDF) (0, 40, 80, 120, 160 and 200 g/kg) and soybean hull (SH) was the only fiber source, providing 0, 75, 150, 225, 300 and 375 g/kg, respectively. Chromic oxide was included at 4 g/kg in all diets as an indigestible marker. In Exp. 2, six crossbred growing barrows (27.6 ± 1.6 kg) were used and the experimental design was the same as for Exp. 1. The six fat-free diets were formulated to include six common fiber-rich ingredients and the concentration of NDF was 100 g/kg. The six fiber-rich ingredients were defatted rice bran (DRB), sugar beet pulp (SBP), rice hull (RH), corn germ meal (CGM), SH and wheat bran (WB) and they were fed at represented 250, 270, 145, 250, 170 and 280 g/kg in the diet, respectively. RESULTS: In Exp. 1, the endogenous loss of fatty acids profile did not change as dietary NDF increased in growing pigs. The endogenous losses of fat, C16:0, C18:0, C18:1, C18:2, total unsaturated fatty acids (UFA) and total saturated fatty acids (SFA) in growing pigs at the end of ileum and throughout the entire intestinal tract increased linearly as NDF content of diets increased. The endogenous losses of fat, as well as C16:0 and C18:0 throughout the entire intestinal tract also increased quadratically as NDF content of diets increased. The ELF increased from 0.71 to 3.14 g/kg of dry matter intake (DMI) and 0.56 to 8.21 g /kg DMI at the end of ileum and throughout the entire intestinal tract in growing pigs, respectively. The ELF occurred in the hindgut except for the growing pigs fed 0 and 4% NDF in their diets. The endogenous losses of C16:0 and UFA occurred primarily in the upper regions of the gut and the greatest endogenous losses of C18:0 occurred in the hindgut. The endogenous losses of fat, individual SFA and total SFA throughout the entire intestinal tract were much greater than that at the end of ileum. However, the endogenous losses of individual UFA and total UFA were less throughout the intestinal tract than at the end of ileum. In Exp. 2, the endogenous losses of fat at the end of ileum were greater in growing pigs fed CGM or WB diets. The endogenous loss of fatty acids profile changed to a slight degree at the end of ileum that the endogenous loss of UFA (particularly C18:1 and C18:2) in growing pigs fed CGM or WB diets were greater (P <  0.01) than that for the other four diets. The greatest (P <  0.01) endogenous loss of SFA (particularly C18:0) was in growing pigs fed the RH diet. The endogenous losses of fat, C16:0, C18:0 and SFA over the entire intestinal tract were much greater in growing pigs fed CGM or WB diets, whereas the lowest values were in growing pigs fed DRB diet. The ELF at the end of ileum in growing pigs fed CGM or WB diets were 3.50 or 4.17 g/kg DMI, respectively, and the ELF over the entire intestinal tract was 7.23 or 7.38 g/kg DMI. The contribution in percentage of ELF in the upper gut was greater than that in the hindgut of growing pigs fed DRB and RH diets, while the ELF in the upper gut and hindgut were equal in growing pigs fed SBP, CGM and WB diets. On the whole, the endogenous losses of C18:1 and C18:2 throughout the entire intestinal tract in growing pigs fed the six fiber-rich ingredients diets were less than losses at the end of ileum, whereas the endogenous loss of fat, C16:0, C18:0 and SFA were greater throughout the intestinal tract than at the end of ileum. CONCLUSION: The profile of loss in endogenous fatty acids did not change as dietary NDF increased in growing pigs and the endogenous losses of fatty acids (C16:0, C18:0, C18:1 and C18:2) fat, UFA and SFA increased linearly as NDF content increased in the diets of pigs. The endogenous losses of fat or fatty acids at the end of ileum were greater in growing pigs fed RH, CGM or WB diets. The endogenous losses of fat, fatty acids (C16:0 and C18:0) and SFA were greater over the entire intestinal tract in pigs fed CGM or WB diet, while these values were the lowest in growing pigs fed the DRB diet. The contribution in percentage losses of fat in the upper gut were greater than in the hindgut of growing pigs fed DRB and RH diets, while the contribution of losses of fat in the upper gut and hindgut were equal in growing pigs fed SBP, CGM and WB diets. In addition, the endogenous loss of individual or total UFA was less over the entire intestinal tract of growing pigs fed fiber diets than that at the end of ileum, and the greatest endogenous losses of fat, individual or total SFA were over the entire intestinal tract. Therefore, differences in fiber content and the nature of fiber-rich ingredients in diets of pigs have different effects to the endogenous losses of fat or fatty acids. Considering the requirement of fat or fatty acids of pigs, careful attention must be paid that the endogenous losses of fat and fatty acids when fiber ingredients are used in diets of pigs.

Effect of different time intervals after feeding on plasma metabolites in growing pigs: an UPLC-MS-based metabolomics study.

A diet consumed by pigs provides the nutrients for the production of a large number of metabolites that, after first-pass metabolism in the liver, circulate systemically where they may exert diverse physiologic influences on pigs. So far, little is known of how feeding elicits changes in metabolic profiles for growing pigs. This study investigated differences in plasma metabolites in growing pigs at several intervals after feeding using the technique of metabolomics. Ten barrows (22.5 ± 0.5 kg BW) were fed a corn-soybean meal basal diet and were kept in metabolism crates for a period of 11 days. An indwelling catheter was inserted into the jugular vein of each pig before the experimental period. Plasmas before and 1, 4, and 8 hr after feeding were collected at day 11 and differential metabolites were determined using a metabolomics approach. Direct comparison at several intervals after feeding revealed differences in 14 compounds. Identified signatures were enriched in metabolic pathways related to linoleic acid metabolism, arginine and proline metabolism, lysine degradation, glycine, serine and threonine metabolism, and lysine biosynthesis. These results suggest that plasma metabolites of growing pigs after feeding were modulated through changes in linoleic acid metabolism and amino acid metabolism.

Effects of pyrroloquinoline quinone supplementation on growth performance and small intestine characteristics in weaned pigs.

This study was conducted to explore the effect of graded levels of pyrroloquinoline quinone disodium (PQQ·Na2) on the performance and intestinal development of weaned pigs. A total of 216 pigs weaned at 28 d were assigned in a randomized complete block design to 6 diets containing 0, 1.5, 3.0, 4.5, 6.0, or 7.5 mg/kg PQQ·Na2 for 28 d. Performance, diarrhea incidence, intestinal morphology, redox status, cytokines, and the expression of tight junction proteins were determined. Pigs had increased ADG (linear, P < 0.01), G:F (quadratic, P < 0.01), and lower diarrhea incidence (P < 0.01) with the increase of PQQ·Na2 supplementation. Villus height increased (quadratic, P < 0.01) in all segments of the small intestine, and crypt depth in the duodenum and jejunum was decreased (linear, P < 0.05) in pigs with the increase of PQQ·Na2 supplementation. Pigs fed PQQ·Na2-supplemented diets had higher (P < 0.05) activities of antioxidant enzymes including total superoxide dismutase in duodenum, jejunum, and ileum; glutathione peroxidase (GSH-Px) in jejunum and ileum; catalase (CAT) in duodenum and ileum; and lower (P < 0.05) malondialdehyde concentrations in the intestinal mucosa of all segments. In the intestinal mucosa, cytokines including interleukin (IL)-1ß, IL-2, and interferon-γ were significantly decreased (P < 0.05) in pigs fed PQQ·Na2-supplemented diets. The protein expression of zonula occluden protein-1 (ZO-1) and occludin in the jejunum was significantly increased (P < 0.05) in pigs fed diets containing PQQ·Na2. In conclusion, these results have indicated that dietary PQQ·Na2 supplementation improves growth performance and gut health in weaned pigs. Moreover, pigs fed diet with as low as 1.5-mg/kg PQQ·Na2 have better performance compared with pigs fed no PQQ·Na2-supplemented diet; pigs fed diet with 4.5-mg/kg PQQ·Na2 have highest G:F among treatments during the whole period.

Integrative analysis of indirect calorimetry and metabolomics profiling reveals alterations in energy metabolism between fed and fasted pigs.

BACKGROUND: Fasting is a simple metabolic strategy that is used to estimate the maintenance energy requirement where the energy supply for basic physiological functions is provided by the mobilization of body reserves. However, the underlying metabolic components of maintenance energy expenditure are not clear. This study investigated the differences in heat production (HP), respiratory quotient (RQ) and plasma metabolites in pigs in the fed and fasted state, using the techniques of indirect calorimetry and metabolomics. METHODS: Nine barrows (45.2 ± 1.7 kg BW) were fed corn-soybean based meal diets and were kept in metabolism crates for a period of 14 d. After 7 d adaptation, pigs were transferred to respiratory chambers to determine HP and RQ based on indirect calorimetry. Pigs were fed the diet at 2,400 kJ ME/(kg BW0.6·d) during d 8 to 12. The last 2 d were divided into 24 h fasting and 48 h fasting treatment, respectively. Plasma samples of each pig were collected from the anterior vena cava during the last 3 d (1 d while pigs were fed and 2 d during which they were fasted). The metabolites of plasma were determined by high-resolution mass spectrometry using a metabolomics approach. RESULTS: Indirect calorimetry analysis revealed that HP and RQ were no significant difference between 24 h fasting and 48 h fasting, which were lower than those of fed state (P <  0.01). The nitrogen concentration of urine tended to decrease with fasting (P = 0.054). Metabolomics analysis between the fed and fasted state revealed differences in 15 compounds, most of which were not significantly different between 24 h fasting and 48 h fasting. Identified compounds were enriched in metabolic pathways related to linoleic acid metabolism, amino acid metabolism, sphingolipid metabolism, and pantothenate and CoA biosynthesis. CONCLUSION: These results suggest that the decreases in HP and RQ of growing pigs under fasting conditions were associated with the alterations of linoleic acid metabolism and amino acid metabolism. The integrative analysis also revealed that growing pigs under a 24-h fasting were more appropriate than a 48-h fasting to investigate the metabolic components of maintenance energy expenditure.