Effects of Dietary Crude Protein Levels on Fecal Crude Protein, Amino Acids Flow Amount, Fecal and Ileal Microbial Amino Acids Composition and Amino Acid Digestibility in Growing Pigs.

The purpose of this experiment was to evaluate the effects of low protein corn-soybean meal-based diets on fecal CP, amino acid (AA) flow amount, AA digestibility and fecal and ileal microbial AA composition in growing pigs. Eighteen pigs (initial body weight = 30 ± 1.35) were randomly divided into three groups and fed with basal diets with CP levels of 12%, 15% and 18%, respectively. The Lys, Met + Cys, Thr and Trp level in the 12% CP and 15% CP groups is the same as 18% CP group by the addition of four crystalline Lys, Met + Cys, Thr and Trp to the diet. The results showed that with the decrease of dietary CP level from 18% to 12%, the fecal total nitrogen (N), CP and total AA (TAA) flow amount decreased linearly (p < 0.05). Dry matter (DM) digestibility, CP digestibility, TAA digestibility, essential amino acid (EAA) digestibility and non-essential amino acid (NEAA) digestibility increased linearly with the decrease of dietary CP concentration from 18% to 12%. Compared with 18% CP group, the flow amount of Asp, Ser, Glu, Gly, Tyr, Val, Leu and Phe in feces of pigs in the 15% CP group and 12% CP group decreased significantly, while the flow amount of Arg in the 15% CP group was lower than that in the 18% CP group and 12% CP group. The fecal microbial N and AA of the 15% CP group were higher than those of the 18% CP and 12% CP groups. Fecal TAA flow amount decreased linearly with the decrease of the dietary CP levels from 18% to 12%. Fecal TAA and NEAA flow amount also decreased linearly with the decrease of dietary CP level from 18% to 12%. Except for Glu, Gly, Met, Tyr, Thr and Phe, there were significant differences among the three groups in the composition of 17 kinds of AAs in fecal microorganisms. Among the 17 AA compositions of ileal microorganisms, except Tyr and Lys, the other AAs were significantly different among the three groups (p < 0.05).

Estimation of between-Cow Variability in Nutrient Digestion of Lactating Dairy Cows Fed Corn-Based Diets.

The objective of this study was to estimate cow variability that can be used to determine the optimal sample size for digestibility trials using lactating dairy cows. Experimental design was randomized complete block design having three blocks and three dietary treatments. Three similarly managed nearby intensive farms were considered as blocks, and three diets were formulated to have 0.7, 1.0, and 1.3 neutral detergent fiber (NDF): starch ratio. In each farm, 18 cows were assigned for each dietary treatment and five sample sizes per each treatment group were simulated by simple random sampling of data from 18, 15, 12, 9 and 6 cows respectively. Intake was not affected by diet or sample size (p > 0.05). Estimated cow variability (as standard deviation) for digestibility of dry matter, NDF and starch were 3.8 g/kg, 5.1 g/kg and 3.3 g/kg, respectively. A major implication of this study is that cow variability is greatest for NDF digestibility and the use of a minimum of 12 cows per dietary treatment is adequate to reliably detect treatment effects on the digestibility of NDF, starch and dry matter using cows fed in groups with randomized block design under these experimental conditions.

ARPP-19 Mediates Herceptin Resistance via Regulation of CD44 in Gastric Cancer.

PURPOSE: As the first-line drug for treatment of HER2-positive metastatic gastric cancer (GC), Herceptin exhibits significant therapeutic efficacy. However, acquired resistance of Herceptin limits the therapeutic benefit of gastric cancer patients, in which the molecular mechanisms remain to be further determined. METHODS: Quantitative real-time polymerase chain reaction was performed to detect the mRNA levels of ARPP-19 and CD44 in GC cells. Protein levels were determined using Western blot and IHC staining. MTT and soft agar colony formation assays were used to measure cell proliferation. Xenograft model was established to verify the functional role of ARPP-19 in Herceptin resistance in vivo. Sphere formation assay was conducted to determine cell stemness. RESULTS: We observed ARPP-19 was up-regulated in Herceptin resistance gastric cancer cells NCI-N87-HR and MKN45-HR. The forced expression of ARPP-19 promoted, whereas the silencing of ARPP-19 impaired Herceptin resistance of HER2-positive gastric cancer cells both in vitro and in vivo. Moreover, ARPP-19 significantly enhanced the sphere formation capacity and CD44 expression, CD44 was also a positive factor of Herceptin resistance in HER2-positive gastric cancer cells. In addition, high level of ARPP-19 was positively associated with Herceptin resistance and poor survival rate of gastric cancer patients. CONCLUSION: We have demonstrated that ARPP-19 promoted Herceptin resistance of gastric cancer via up-regulation of CD44, our study suggested that ARPP-19 could be a potential diagnostic and therapeutic candidate for HER2-positive gastric cancer.

Tryptophan promoted ß-defensin-2 expression via the mTOR pathway and its metabolites: kynurenine banding to aryl hydrocarbon receptor in rat intestine.

In this study, we investigated the signalling pathways mediating tryptophan (Trp)-promoted ß-defensin-2 (BD-2) expression in rat intestinal mucosa. Sprague Dawley rats were administered with l-Trp and treated with rapamycin (RAPA), 1-methyltryptophan (1-MT), or para-chlorophenyl-amine (PCPA) to inhibit mammalian target of rapamycin (mTOR), indoleamine-2,3-dioxygenase (IDO), or tryptophan hydroxylase (TPH), respectively. The mRNA and protein levels of BD-2 in the jejunal and ileal mucosa of rats increased with administration of l-Trp. Intraperitoneal injection of RAPA significantly decreased the mRNA level of BD-2 and the concentrations of p-mTORC1 and BD-2 in the jejunal and ileal mucosa of rats with administration of l-Trp (P < 0.05). Oral administration of 1-MT decreased the IDO activity and the mRNA and protein levels of BD-2, and increased the concentrations of tumour necrosis factor (TNF-α), interleukin (IL)-17, and IL-22 in the jejunal and ileal mucosa of rats with administration of l-Trp (P < 0.05). Intraperitoneal injection of PCPA decreased the TPH activity and increased the mRNA and protein levels of BD-2, but did not change the concentrations of TNF-α, IL-17, or IL-22 in the jejunal and ileal mucosa of rats with administration of l-Trp. The results indicate the Trp-promoted BD-2 expression in the jejunum and ileum via the mTOR pathway and its metabolites: kynurenine banding to aryl hydrocarbon receptor in rat intestine.

Modulation of wound-induced hydrogen peroxide and its influence on the fate of Escherichia coli O157:H7 in cut lettuce tissues.

Wounding of lettuce tissue has been examined previously by others in regard to browning reactions, and treatments to modulate wounding responses were evaluated for reduction of browning. However, the wounding process also releases oxygen radicals such as hydrogen peroxide. This study focused on the evaluation of two treatments that reduce hydrogen peroxide at cut surfaces (heat treatment and pyruvate addition) and one treatment that enhances its production (infusion with the fungal elicitor harpin). Hydrogen peroxide changes in response to treatment were also associated with resultant survival of Escherichia coli O157:H7, which was inoculated onto the lettuce before cutting. Heat-treated lettuce produced significantly less hydrogen peroxide, and microbial analysis showed that E. coli O157:H7 survival on packaged, heat-treated lettuce was higher than on non-heat-treated controls. Lettuce was also cut under a solution of sodium pyruvate (a well-known hydrogen peroxide quencher), and E. coli O157:H7 survival was found to be enhanced with that treatment. When lettuce was infused with harpin before cutting, hydrogen peroxide production was enhanced, and this was associated with reduced survival of E. coli O157:H7. These results collectively support the hypothesis that modulation of wound-generated hydrogen peroxide can have an influence on E. coli O157:H7 survival on cut and packaged romaine lettuce.

Slicing under chlorinated water improves the disinfection of fresh-cut romaine lettuce.

The aim of this study was to determine whether the timing or mode of application influences the antimicrobial efficacy of a sodium hypochlorite solution against microorganisms on fresh-cut Romaine lettuce. Lettuce leaves were treated with a solution of sodium hypochlorite containing 70 mg liter(-1) free chlorine prior to slicing (WLS), while submerged in the solution (CWS), or after slicing (PCS), the last being common practice in the fresh-cut industry. Immediate antimicrobial effects were determined from analyses performed directly after treatment, while delayed effects were derived from analysis of packaged samples stored at 4 and 15°C. Experiments were performed with both uninoculated and inoculated whole leaves, using Escherichia coli O157:H7 from a type collection as an inoculum. The CWS treatment provided the greatest initial reductions in aerobic plate counts of E. coli O157:H7 populations, followed by PCS and WLS. The advantage afforded by the CWS approach was maintained over 10 days in storage at 4°C. In addition, it was noted that the visual quality attributes of the fresh-cut lettuce from the CWS approach were better than those from the other two treatments. These results collectively suggest that slicing lettuce under a sanitizer solution could provide better disinfection of fresh-cut Romaine lettuce than the current practice of washing with sanitizer after cutting has taken place.