T. J. Li

Development of an antioxidant system after early weaning in piglets2

The objective of this experiment was to investigate oxidative injury and the development of an antioxidant system after early weaning in piglets. A total of 40 piglets (Landrace× Large White, weaned at 14 d after birth) were randomly slaughtered 0 (w0d), 1 (w1d), 3 (w3d), 5 (w5d), or 7 d (w7d; n = 8) after weaning. Concentrations of malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and protein carbonyl and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase were measured in plasma. Gene expressions of antioxidant enzymes were determined by quantitative reverse transcription PCR analysis. The mediation of transcription factor 65 (p65) and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways by oxidative stress was determined by Western blot analysis. Results showed that the plasma MDA level was significantly higher at 3 d (P < 0.05) and that the protein carbonyl level increased at 1, 3, and 5 d (P < 0.05) compared with w0d. In addition, early weaning suppressed the plasma activity of SOD at 1 d (P < 0.05) and reduced the GSH-Px activity at 3 d (P < 0.05). The expression results in the jejunum indicate that the genes related to antioxidant enzymes were downregulated (P < 0.05) at 3 and 5 d after weaning. Uncoupling protein 2 (Ucp2), which is considered to be a feedback regulation on reactive oxygen species generation, tended to decrease in the ileum (P < 0.05) after weaning. Tumor protein 53 (p53), which regulates reactive oxygen species generation, was enhanced (P < 0.05) in the jejunum after weaning. Meanwhile, early weaning suppressed p65 (at 3, 5, and 7 d; P < 0.05) and Nrf2 (at 5 and 7 d; P < 0.05) signals in the jejunum, which might feedback-regulate antioxidant gene expression and promote the development of the antioxidant system. Therefore, we speculate that weaning disrupted oxidative balance and caused oxidative injury in piglets, and this imbalance can recover with the development of an antioxidant system via feedback regulation.

Effect of dietary arginine and N-carbamoylglutamate supplementation on reproduction and gene expression of eNOS, VEGFA and PlGF1 in placenta in late pregnancy of sows

The objectives of this study were to investigate the potential mechanisms of dietary arginine (Arg) and N-carbamoylglutamate (NCG) supplementation on reproductive performance of sows. Twenty-seven crossbred (Landrace×Large White) sows with similar body weight and parity at day (90±1) of gestation were assigned randomly into 3 groups (n=9) control group, Arg group, NCG group, and fed with the following diets: a control diet, and the control diet supplemented with 1.0% Arg or 0.1% NCG. Litter size was recorded. Blood samples were obtained for biochemical analyses. Placenta chorioallantoic membrane tissue collected immediately after birth to preserve in RNA stabilizer for mRNA analysis of endothelial nitric oxide synthase (eNOS), endothelial growth factor a (VEGFA) and placenta growth factor 1 (PlGF1) by real time-PCR. The results showed that compared with the control group, the average birth weight of all piglets born alive were 16.2% and 14.3% higher in the Arg and NCG groups (P<0.05), respectively; plasma VEGFA was higher in the Arg group (P<0.05). The expression of VEGFA in the allantochorion tissue of the NCG-supplemented group was higher (P<0.01), and tended to be higher in the Arg-supplemented group (0.05<P<0.1). NCG significantly increased protein concentration of PlGF1 in plasma (P<0.05), and enhanced PlGF1mRNA expression in allantochorion tissue of placenta (P<0.01). The results suggested that dietary Arg and NCG supplementation play important roles in meliorating placental vascular function and promoting the nutrients supply to fetus.

Dietary amylose and amylopectin ratio and resistant starch content affects plasma glucose, lactic acid, hormone levels and protein synthesis in splanchnic tissues.

Experiments were conducted to determine the effects of feeding different starch sources on piglets. Four diets were formulated with maize, brown rice, sticky rice and Hi-Maize 1043 as starch sources, with resistant starch (RS) contents of 2.3%, 0.9%, 0.0%, 20.6%, and amylose and amylopectin ratio of 0.23%, 0.21%, 0.18%, 0.06% respectively. Fifty-six pigs weaned at 28 days of age were randomly assigned to one of the four diets. In Exp. 1, six piglets in each group were fitted with an indwelling jugular catheter. After 25 days of feeding trial, venous blood samples were obtained at time zero and every 1 h for 4 h. In Exp. 2, the remaining piglets were used to determine the effects of different starch sources on the fractional synthesis rate (FSR). The results indicated that feeding the Hi-Maize 1043 diet decreased (p < 0.05) plasma contents of glucose, insulin, lactic acid and T(3), while sticky rice increased plasma contents of glucose and insulin. The insulin contents in piglets fed the sticky rice diet was 69.2 microIU/ml at 1 h post-feeding which was highest among the starch diets. The FSR in the pancreas, spleen, duodenum, jejunum, ileum and colon in the corn group were much higher (p < 0.05) than that in the sticky rice group. These results suggest that RS is potentially beneficial for improving insulin sensitivity in young pigs and that the ratio of amylose and amylopectin have significantly effects on the FSR in splanchnic tissues in weaned piglets. Another finding of this study indicated maize with a ratio of amylose and amylopectin of 0.23 has the best starch sources for pig production.

Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: I. Growth performance, immune function, and antioxidation capacity1

The mycotoxin deoxynivalenol (DON) is a food contaminant that leads to reduced feed intake and reduced BW gain, as well as organ impairment. On the other hand, antimicrobial peptides have been shown to have positive effects on growth performance, nutrient digestibility, and immune function. The purpose of this study was to investigate the protective effects of composite antimicrobial peptides (CAP) on piglets challenged with DON. After a 7-d adaptation period, 28 individually housed piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% CAP (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 ppm DON + 0.4% CAP (DON + CAP). On d 15 and 30 after the initiation of treatment, blood samples were collected for the determination of blood profile. Piglets were monitored for 30 d to assess performance and then were slaughtered to obtain organs for the determination of the relative weight of organs. The results showed that dietary supplementation with DON decreased (P < 0.05) ADFI, ADG, and G:F, whereas dietary supplementation with CAP improved ADG and G:F (P < 0.05). The relative weight of the kidney and pancreas was greater and the relative weight of the spleen was lighter in the DON treatment than in the other 3 treatments (P < 0.05). There were no effects (P > 0.05) on other relative weights of viscera, except the relative weight of the gallbladder, but the diamine oxidase activity in the liver decreased in DON-treated piglets (P < 0.05). Piglets in the DON treatment had increased serum concentrations of alkaline phosphatase, alanine transaminase, and aspartate aminotransferase and a dramatic decrease in total protein (P < 0.05), whereas there were no differences (P > 0.05) between the DON + CAP treatment and the other treatments. The DON treatment decreased the numbers of red blood cells and platelets, as well as the serum catalase concentrations, and decreased the serum concentrations of H2O2, maleic dialdehyde, and nitric oxide (P < 0.05). The numbers of platelets and thrombocytocrit, as well as the serum concentrations of catalase, were greater, whereas the maleic dialdehyde concentrations were decreased, in both the CAP and DON + CAP treatments compared with the other treatments (P < 0.05). Compared with the control treatment, DON decreased peripheral lymphocyte proliferation on d 15, whereas supplementation with CAP increased it on d 15 and 30 (P < 0.05). These findings indicate that CAP could improve feed efficiency, immune function, and antioxidation capacity and alleviate organ damage, and thus, it has a protective effect in piglets challenged with DON.

Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: II. Intestinal morphology and function.

Deoxynivalenol (DON) affects animal and human health and targets the gastrointestinal tract. The objective of this study was to evaluate the ability of composite antimicrobial peptides (CAP) to repair intestinal injury in piglets challenged with DON. A total of 28 piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% composite antimicrobial peptide (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 mg/kg DON + 0.4% CAP (DON + CAP). After an adaptation period of 7 d, blood samples were collected on d 15 and 30 after the initiation of treatment for determinations of the concentrations of D-lactate and diamine oxidase. At the end of the study, all piglets were slaughtered to obtain small intestines for the determination of intestinal morphology, epithelial cell proliferation, and protein expression in the mammalian target of rapamycin (mTOR) signaling pathway. The results showed that DON increased serum concentrations of D-lactate and diamine oxidase, and these values in the CAP and DON + CAP treatments were less than those in the NC and DON treatments, respectively (P < 0.05). The villous height/crypt depth in the jejunum and ileum and the goblet cell number in the ileum in the CAP and DON + CAP treatments were greater than those in the NC and DON treatments (P < 0.05). The proliferating cell nuclear antigen (PCNA) labeling indexes for the jejunum and ileum in the DON + CAP treatment were greater than those in the DON treatment (P < 0.05). The DON decreased (P < 0.05) the relative protein expression of phosphorylated Akt (Protein Kinase B) and mTOR in the jejunal and ileal mucosa and of phosphorylated 4E-binding protein 1 (p-4EBP1) in the jejunal mucosa, whereas CAP increased (P < 0.05) the protein expression of p-4EBP1 in the jejunum. These findings showed that DON could enhance intestinal permeability, damage villi, cause epithelial cell apoptosis, and inhibit protein synthesis, whereas CAP improved intestinal morphology and promoted intestinal epithelial cell proliferation and protein synthesis, indicating that CAP may repair the intestinal injury induced by DON.

Effects of oral supplementation with glutamate or combination of glutamate and N-carbamylglutamate on intestinal mucosa morphology and epithelium cell proliferation in weanling piglets

To evaluate the effects of glutamate (Glu) or combination of Glu and N-carbamylglutamate (NCG) on intestinal mucosa morphology and epithelium cell proliferation, 18 piglets weaned at 21 d (BW 5.56 ± 0.51 kg) were grouped into 3 treatments and fed one of the following diets for 20 d: a standard diet (SD), SD+Glu(1%), or SD+Glu(1%)+NCG(0.05%). All the piglets were killed for intestinal mucosa collection, and real-time PCR was used to detect mRNA abundance of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), and β-catenin. The results showed that compared with the control group, adding Glu or Glu+NCG to the diet resulted in a higher villus height and mucosal thickness (P < 0.05) in the jejunum. However, the villus height/crypt depth ratio was unaltered. The RT-PCR results showed that Glu+NCG significantly increased PCNA mRNA abundance in both jejunum and ileum (P < 0.05), while they also significantly increased β-catenin and VEGF mRNA abundance in ileum (P < 0.05). Only Glu increased PCNA mRNA abundance in the jejunum (P < 0.05) and β-catenin mRNA in the jejunum (P < 0.05). These results indicated that oral supply of Glu improved intestinal mucosa morphology, and combined Glu and NCG may have favorable effects on intestinal epithelium cell proliferation than Glu alone.

The effect of dietary addition of a polysaccharide from Atractylodes macrophala Koidz on growth performance, immunoglobulin concentration and IL-1β expression in weaned piglets

The present study was conducted to determine the effects of a polysaccharide of Atractylodes macrophala Koidz (PAM) as a dietary additive on growth performance, immunoglobulin concentration and IL-1β expression in weaned piglets. One hundred and twenty Landrace x Yorkshire piglets weaned at 28 days old (body weight 7·5±0·07 kg) were assigned to five treatment groups (three pens/ group, eight piglets/pen) fed maize/soybean-based diets supplemented with 0, 3, 6 or 9 g of PAM/kg diet or antibiotics (0·4 g flavomycin/kg+0·13 g olaquindox/kg). The experimental period was 28 days. With increasing PAM supplementation levels, average daily gain was greater (quadratic, P<0·05) and the ratio of amount fed to live weight (LW) gain (feed/gain) improved (quadratic, P<0·05) during days 14-28 and overall, and diarrhoea incidence decreased (linear, P<0·05) during days 14-28. Supplementation of PAM also increased (quadratic, f<0·05) serum concentrations of interleukin (IL)-2 and IL-6 on day 14, and increased (quadratic, P<0·05) IL-1β expression in jejunal mucosa and lymph nodes. Concentrations of PAM between 6 and 9 g/kg presented the strongest bioactivity compared to the control group or antibiotic-fed group. These findings indicate that PAM is effective in improving growth performance and cytokine response, which suggests that PAM can be used as a diet additive for weanling piglets.

Dietary protein, energy and arginine affect LAT1 expression in forebrain white matter differently

L-type amino acid transporter-1 (LAT1) transports large, branched-chain, aromatic and neutral amino acids. About 64 Duroc × Landrace × Yorkshire pigs were used to study the effects of dietary crude protein (CP), energy and arginine on LAT1 expression in forebrain. The results showed that LAT1 expression in forebrain was sensitive to different levels of CP, energy and arginine. On the basis of Western blot analysis, a lower level of LAT1 presented in the brain tissues of pigs fed the low dietary CP diet (P < 0.05), a higher level were found in pigs fed the higher CP diet, with moderate to intense staining seen in pigs fed the diet plus 1% arginine. In contrast, pigs fed the control-energy diet had weak LAT1 expression, and those fed the diet supplemented with 1% arginine showed lowest LAT1 expression (P < 0.05). These results showed that LAT1 was highly expressed in the forebrain, and expression of LAT1 was affected by dietary protein, energy and arginine differently.

Single-Frequency Laser at 473 nm by Twisted-Mode Technique

We experimentally demonstrate an all solid-state laser producing single-frequency output at 473 nm. Spatial gain hole-burning in the gain material has been eliminated by use of twisted-mode cavity approach. By carefully designing, a V-cavity with two beam waists is chosen to provide the optimum beam radius in the gain medium Nd:YAG and second harmonic generation crystal LBO. A total output power of 105 mW was achieved when the laser was diode-end-pumped at an incident power of 3.5 W; the light-light conversion efficiency is up to 3%.

Fermentation Characterization of Chinese Yam Polysaccharide and Its Effects on the Gut Microbiota of Rats

Rat was used to characterize Chinese Yam polysaccharides (CYPs). In Exp. 1, maximum volume and rate of gas production in CYP 3-supplemented group were higher than other CYP-supplemented groups and control group, while pH values and NH3 contents in CYP 2-, CYP 3-, and CYP 4-supplemented groups were lower than control group. Contents of acetate, propionate and butyrate increased by supplementing CYP 3 or CYP 4 compared to other groups, except for glucose-supplemented group. Contents of isobutyrate for CYPs groups decreased compared to control group. CYP 3 enhanced beneficial gut microbiota, but suppressed bacterial pathogens. In Exp. 2, contents of acetate and butyrate in cecal digesta of rats fed 0.25 or 0.5 g/kg CYP 3 were higher than other groups on day 7. pH values in 0.25 and 0.5 g/kg groups were lower than 1.0 g/kg group. Contents of acetate in 0.25 and 0.5 g/kg groups were greater than other 2 groups on day 21. Gut microflora in CYP 3-supplemented rats had greater diversity than non-supplemented rats. CYP 3 enriched beneficial gut microbiota, but suppressed bacterial pathogens in rat cecum. These findings suggested that CYP 3 is a good source of carbon and energy, and may improve bacterial community diversity and modulate short-chain fatty acid production in hindgut of rats.