Manganese alleviates heat stress of primary cultured chick embryonic myocardial cells via enhancing manganese superoxide dismutase expression and attenuating heat shock response.

Manganese (Mn) is an essential trace element that has been shown to attenuate the adverse effects of heat stress in the heart of broiler breeders and embryos. However, the underlying molecular mechanisms involving this process remain unclear. Therefore, two experiments were conducted to investigate the possible protective mechanisms of Mn on primary cultured chick embryonic myocardial cells exposed to heat challenge. In experiment 1, the myocardial cells were exposed to 40 °C (normal temperature, NT) and 44 °C (high temperature, HT) for 1, 2, 4, 6 or 8 h. In experiment 2, the myocardial cells were preincubated with no Mn supplementation (CON), 1 mmol/L of Mn as the inorganic MnCl2 (iMn) or organic Mn proteinate (oMn) under NT for 48 h, and then continuously incubated under NT or HT for another 2 or 4 h. The results from experiment 1 showed that the myocardial cells incubated for 2 or 4 h had the highest (P < 0.0001) heat-shock protein 70 (HSP70) or HSP90 mRNA levels than those incubated for other incubation times under HT. In experiment 2, HT increased (P < 0.05) the heat-shock factor 1 (HSF1) and HSF2 mRNA levels as well as Mn superoxide dismutase (MnSOD) activity of myocardial cells compared with NT. Furthermore, supplemental iMn and oMn increased (P < 0.02) HSF2 mRNA level and MnSOD activity of myocardial cells compared with the CON. Under HT, the HSP70 and HSP90 mRNA levels were lower (P < 0.03) in iMn group than in the CON group, in oMn group than in iMn group; and the MnSOD mRNA and protein levels were higher (P < 0.05) in oMn group than in the CON and iMn groups. These results from the present study indicate that supplemental Mn, especially oMn, could enhance the MnSOD expression and attenuate heat shock response to protect against heat challenge in primary cultured chick embryonic myocardial cells.

Novel Hybrid Peptide Cathelicidin 2 (1-13)-Thymopentin (TP5) and Its Derived Peptides with Effective Antibacterial, Antibiofilm, and Anti-Adhesion Activities.

The increasing numbers of infections caused by multidrug-resistant (MDR) pathogens highlight the urgent need for new alternatives to conventional antibiotics. Antimicrobial peptides have the potential to be promising alternatives to antibiotics because of their effective bactericidal activity and highly selective toxicity. The present study was conducted to investigate the antibacterial, antibiofilm, and anti-adhesion activities of different CTP peptides (CTP: the original hybrid peptide cathelicidin 2 (1-13)-thymopentin (TP5); CTP-NH2: C-terminal amidated derivative of cathelicidin 2 (1-13)-TP5; CTPQ: glutamine added at the C-terminus of cathelicidin 2 (1-13)-TP5) by determining the minimal inhibitory concentrations (MICs), minimal bactericidal concentrations (MBCs), propidium iodide uptake, and analysis by scanning electron microscopy, transmission electron microscopy, and confocal laser scanning microscopy). The results showed that CTPs had broad-spectrum antibacterial activity against different gram-positive and gram-negative bacteria, with MICs against the tested strains varying from 2 to 64 µg/mL. CTPs at the MBC (2 × MIC 64 µg/mL) showed strong bactericidal effects on a standard methicillin-resistant Staphylococcus aureus strain ATCC 43300 after co-incubation for 6 h through disruption of the bacterial membrane. In addition, CTPs at 2 × MIC also displayed effective inhibition activity of several S. aureus strains with a 40-90% decrease in biofilm formation by killing the bacteria embedded in the biofilms. CTPs had low cytotoxicity on the intestinal porcine epithelial cell line (IPEC-J2) and could significantly decrease the rate of adhesion of S. aureus ATCC 43300 on IPEC-J2 cells. The current study proved that CTPs have effective antibacterial, antibiofilm, and anti-adhesion activities. Overall, this study contributes to our understanding of the possible antibacterial and antibiofilm mechanisms of CTPs, which might be an effective anti-MDR drug candidate.

Kinetics of phosphorus absorption and expressions of related transporters in primary cultured duodenal epithelial cells of chick embryos.

Two experiments were conducted to investigate the kinetics of phosphorus (P) absorption and expressions of type IIb sodium-dependent phosphate cotransporter (NaP-IIb), inorganic phosphate transporters 1 and 2 (PiT-1 and PiT-2) in primary cultured duodenal epithelial cells of chick embryos. In experiment 1, the P absorptions across duodenal epithelial cell monolayers at different incubation time points (0, 10, 20, 40, 60, 80, 100 and 120 min) were compared. In experiment 2, the kinetics of P absorption was performed at 40 min after incubation of duodenal epithelial cells with the media containing 0, 0.75, 1.5, 3.0, 6.0, 12.0, 24.0 and 48.0 mmol P/L as KH2 PO4 , and the mRNA and protein expression levels of NaP-IIb, PiT-1 and PiT-2 in duodenal epithelial cells with the media containing 0, 6.0 and 48.0 mmol P/L were determined at 87 min after incubation. The results from experiment 1 showed that the P absorption increased linearly (p < .0001) from 0 to 80 min and the fastest increase occurred at 40 min; the asymptotic model was shown to have the best fit degree, and the optimal incubation time for saturable P absorption was determined to be 87 min. The kinetic curves of P absorption from experiment 2 demonstrated that P absorption was a mixed process of a non-saturable diffusion plus a saturable carrier-mediated transport across the duodenal epithelial cells. The high P concentration (48.0 mmol/L) decreased (p < .05) NaP-IIb and PiT-1 mRNA and protein levels and increased (p < .0001) PiT-2 mRNA level. These results indicated that the P absorption across primary cultured duodenal epithelial cell monolayers of chick embryos was a mixed process of a non-saturable diffusion plus a saturable carrier-mediated transport and could be restricted by reducing the NaP-IIb and PiT-1 expressions while increasing the PiT-2 expression at a high P concentration.

Relative bioavailability of selenium yeast for broilers fed a conventional corn-soybean meal diet.

The present study was conducted to assess the relative bioavailability of selenium (Se) as Se yeast (SY) relative to sodium selenite (SS) for broilers fed a conventional corn-soybean meal diet. A total of 360 one-d-old Arbor Acres commercial broilers were randomly assigned to 5 treatments with 6 replicates per treatment in a completely randomized design involving a 2 (Se sources: SY and SS) × 2 (added Se levels: 0.20 and 0.40 mg Se/kg) factorial design of treatments plus 1 (a Se-unsupplemented control diet) for 42 days. The results showed that Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney of broilers on d 21 and 42, glutathione peroxidase (GSH-Px) activity in the pancreas on d 21 as well as in the breast muscle and pancreas on d 42, and GSH-Px mRNA levels in the liver, heart, breast muscle and pancreas on d 21 increased linearly (p < .03) as levels of added Se increased. Furthermore, a difference (p ≤ .05) between SY and SS was detected for Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney, GSH-Px activity in pancreas on both d 21 and 42, as well as pancreatic GSH-Px mRNA level on d 21. Based on slope ratios from the multiple linear regressions of the above indices, the Se bioavailabilities of SY relative to SS (100%) were 111%-394% (p ≤ .05) when calculated from the Se concentrations in plasma, liver, heart, breast muscle, pancreas, kidney and GSH-Px activities in pancreas on d 21 and 42, as well as GSH-Px mRNA level in pancreas on d 21. The results from this study indicated that the Se from SY was more available for enhancing the Se concentrations in plasma or tissues and the expression and activity of GSH-Px in pancreas of broilers than the Se from SS.

Dietary supplemental vitamin D3 enhances phosphorus absorption and utilisation by regulating gene expression of related phosphate transporters in the small intestine of broilers.

The present study was carried out to evaluate the effect of dietary supplemental vitamin D3 (VD3) on P absorption and utilisation as well as its related mechanisms in the small intestine of broilers. A total of 384 1-d-old Arbor Acres male broilers were assigned randomly into four treatments following a completely randomised design with a 2 (dietary non-phytate P (NPP) contents: 0·43 and 0·22 %)×2 (dietary VD3 supplemental levels: 0 and 87·5 µg/kg) factorial arrangement. The experiment lasted for 22 d. The results showed that P contents in serum from the hepatic portal vein and tibia ash of broilers were higher (P<0·05) for 0·43 % NPP than for 0·22 % NPP. The type IIb Na-dependent phosphate cotransporter (NaP-IIb) protein expressions in the duodenum and ileum were higher (P<0·05) also for 0·43 % NPP than 0·22 % NPP. Supplementation of VD3 enhanced (P<0·05) tibia P retention rate and type III Na-dependent phosphate cotransporter (PiT)-1 protein expression in the duodenum of all broilers. Moreover, VD3 supplementation decreased (P<0·002) mortality and increased (P<0·02) serum P content from the hepatic portal vein after 4 h of feeding, tibia ash content, tibia ash P content and protein expressions of NaP-IIb and PiT-1 in the jejunum of broilers fed diet with 0·22 % NPP. Thus, dietary supplemental VD3 promoted intestinal P absorption and bone P utilisation, and this effect might be associated with enhanced PiT-1 levels in the duodenum and PiT-1 and NaP-IIb levels in the jejunum respectively when dietary NPP is limiting.

Maternal manganese activates anti-apoptotic-related gene expressions via miR-1551 and miR-34c in embryonic hearts from maternal heat stress (Gallus gallus).

MicroRNAs (miRNAs) expressions are altered by maternal stresses and nutritional status. Our previous study has demonstrated that maternal manganese (Mn) addition could protect chick embryos against maternal heat stress via enhancing anti-apoptotic ability in embryonic hearts. The objective of this study was to investigate whether this protective effect could be achieved via miRNA mechanisms, and also be sustained in offspring broilers. A completely randomized design with a 2 (maternal normal and high temperatures: 21 and 32 °C) × 2 (maternal control basal diet and the basal diet + 120 mg Mn/kg) factorial arrangement of treatments was adopted. Totally 96 broiler breeder hens were allotted to 4 treatments with 6 replicates. Subsequently, 24 hatched chicks from each maternal treatment were divided into 6 replicates. Maternal supplemental 120 mg Mn/kg reduced the increased expressions of miR-1551 and miR-34c in hearts of offspring embryos but not broilers under maternal heat stress. B-cell CLL/lymphoma 2 (BCL2) and NF-κB-inducing kinase (NIK) genes related to anti-apoptotic ability were identified as direct targets for miR-1551 and miR-34c, respectively. Under maternal heat stress, maternal supplemental 120 mg Mn/kg activated target BCL2 expression and NIK-dependent NF-κB pathway via mediating miR-1551 and miR-34c expressions in hearts of offspring embryos rather than broilers.

Effects of environmental temperature and dietary zinc on egg production performance, egg quality and antioxidant status and expression of heat-shock proteins in tissues of broiler breeders.

To investigate the effects of environmental temperature and dietary Zn on egg production performance, egg quality and antioxidant status, as well as expression of heat-shock proteins (HSP) in tissues, of laying broiler breeders, we used a completely randomised design with a 2×3 factorial arrangement of treatments. The two environmental temperatures were normal (21±1°C, NT) and high (32±1°C, HT). The three dietary Zn sources were a Zn-unsupplemented basal diet (CON), and the basal diet supplemented with 110 mg Zn/kg as either the inorganic Zn sulphate (iZn) or the organic Zn proteinate with a moderate chelation strength (oZn). HT decreased (P<0·002) egg weight, laying rate, eggshell strength, thickness and weight, but increased (P≤0·05) rectal temperature, broken egg rate, misshapen egg rate, feed:egg ratio, Cu Zn superoxide dismutase activities in liver and pancreas, as well as metallothionein (MT) level in pancreas, and HSP70 mRNA levels in liver and pancreas of laying broiler breeders. Broiler breeders fed the oZn diet had higher (P<0·04) Zn content in the liver, as well as MT levels in the liver and pancreas, compared with those fed the CON diet. Under HT, broiler breeders fed the oZn diet had higher (P<0·05) Zn content in the pancreas compared with those fed the iZn and CON diets. The results from this study indicated that HT impaired egg production performance and eggshell quality possibly because of the disturbed redox balance and HSP homoeostasis, whereas the oZn is more available than the iZn for pancreatic Zn of heat-stressed laying broiler breeders.

Phosphorus absorption and gene expression levels of related transporters in the small intestine of broilers.

To investigate the P absorption and gene expression levels of related co-transporters, type IIb sodium-dependent phosphate co-transporter (NaPi-IIb), inorganic phosphate transporter 1 (PiT-1) and inorganic phosphate transporter 2 (PiT-2) in the small intestine of broilers, 450 1-d-old Arbor Acres male broilers were randomly allocated to one of three treatments with ten replicate cages of fifteen birds per cage for each treatment in a completely randomised design. Chickens were fed a diet with no added inorganic P (containing 0·06 % non-phytate P (NPP)) or with either 0·21 or 0·44 % NPP for 21 d. Plasma P concentration in the hepatic portal vein, mRNA and protein expression levels of NaPi-IIb, PiT-1 and PiT-2 were determined at 7, 14 and 21 d of age. The results showed that the concentration of P in plasma in the hepatic portal vein increased as dietary NPP increased (P<0·0001). At 14 and 21 d of age, the increase in dietary NPP inhibited (P<0·003) NaPi-IIb mRNA expression level in the duodenum, as well as PiT-1 mRNA and protein expression levels in the ileum, but promoted NaPi-IIb protein expression level (P<0·002) and PiT-2 mRNA and protein expression levels (P<0·04) in the duodenum. These results suggest that NaPi-IIb, PiT-1 and PiT-2 might be important P transporters in the small intestine of broilers. Higher intestinal P absorption may be achieved by up-regulating the protein expression levels of NaPi-IIb and PiT-2 and down-regulating the protein expression of PiT-1.

Manganese influences the expression of fatty acid synthase and malic enzyme in cultured primary chicken hepatocytes.

Two experiments were designed to investigate the effects of Mn source and concentration on the mRNA expression and enzymatic activities of fatty acid synthase (FAS) and malic enzyme (ME) in cultured primary broiler hepatocytes. In Expt 1, primary broiler hepatocytes were treated with 0 (control), 0·25, 0·50 or 0·75 mmol/l of Mn as inorganic manganese chloride (MnCl2.4H2O) for 24 and 48 h. In Expt 2, primary broiler hepatocytes were incubated with 0 (control), 0·25 or 0·50 mmol/l of Mn as either manganese chloride or Mn-amino acid chelate for 48 h. The mRNA levels and activities of FAS and ME in the hepatocytes were measured in Expts 1 and 2. The results in Expt 1 showed that only at 48 h mRNA expression levels of FAS and ME in the hepatocytes decreased linearly (P0·33) on any of the measured cellular parameters. The results suggested that Mn might reduce cell damage and regulate FAS and ME expression at a transcriptional level in primary cultured broiler hepatocytes.

Determination of dietary iron requirements by full expression of iron-containing cytochrome c oxidase in the heart of broilers from 22 to 42 d of age.

The present study was carried out to determine dietary Fe requirements for the full expression of Fe-containing enzyme in broilers chicks from 22 to 42 d of age. At 22 d of age, 288 Arbor Acres male chicks were randomly assigned to one of six treatments with six replicates and fed a basal maize-soyabean-meal diet (control, containing 47·0 mg Fe/kg) or the basal diet supplemented with 20, 40, 60, 80 or 100 mg Fe/kg from FeSO4.7H2O for 21 d. Regression analysis was performed to estimate the optimal dietary Fe level using quadratic models. Liver cytochrome c oxidase (Cox), heart Cox and kidney succinate dehydrogenase mRNA levels as well as heart COX activity were affected (P<0·08) by dietary Fe level, and COX mRNA level and activity in heart of broilers increased quadratically (P<0·03) as dietary Fe level increased. The estimates of dietary Fe requirements were 110 and 104 mg/kg for the full expression of Cox mRNA and for its activity in the heart of broilers, respectively. The results from this study indicate that COX mRNA level and activity in the heart are new and sensitive criteria to evaluate the dietary Fe requirements of broilers, and the dietary Fe requirements would be 104-110 mg/kg to support the full expression of COX in the heart of broiler chicks from 22 to 42 d of age, which are higher than the current National Research Council Fe requirement (80 mg/kg) of broiler chicks from 1 to 21 d or 22 to 42 d of age.

Determination of Dietary Iron Requirements by Full Expression of Iron-Containing Enzymes in Various Tissues of Broilers.

BACKGROUND: The current dietary iron requirement (80 mg/kg) of broilers is mainly based on growth, hemoglobin concentration, or hematocrit data obtained in a few early studies; however, expressions of iron-containing enzymes might be more sensitive novel criteria to evaluate dietary iron requirements. OBJECTIVE: The objective of this study was to determine dietary iron requirements of broilers for the full expression of succinate dehydrogenase (SDH), catalase, and cytochrome c oxidase (COX) in various tissues. METHODS: A total of 336 1-d-old Arbor Acres male chicks were randomly assigned to 1 of 7 treatments with 6 replicates and fed a basal corn and soybean-meal diet (control, containing 67 mg Fe/kg) and the basal diet supplemented with 20, 40, 60, 80, 100, or 120 mg Fe/kg from FeSO4 ⋅ 7H2O for 21 d. Regression analysis was performed to estimate the optimal dietary iron concentration with the use of broken-line or quadratic models. RESULTS: SDH activity in the liver and heart, COX and catalase activity in the liver, Sdh mRNA levels in the liver, and Cox mRNA levels in the liver and heart of broilers were affected (P < 0.027) by supplemental iron concentration, and increased quadratically (P < 0.004) as dietary iron concentration increased. Dietary iron requirements estimated on the basis of fitted broken-line or quadratic-curve models (P < 0.005) of the above indexes were 97-136 mg/kg. CONCLUSIONS: SDH activity in the liver and heart, COX and catalase activity in the liver, Sdh mRNA levels in the liver, and Cox mRNA levels in the liver and heart are, to our knowledge, new and sensitive criteria to evaluate the dietary iron requirements of broilers, and the dietary iron requirements would be 97-136 mg/kg to support the full expression of the above iron-containing enzymes in various tissues of broiler chicks from 1 to 21 d of age, which are higher than the current NRC iron requirement.

Use of molecular biomarkers to estimate manganese requirements for broiler chickens from 22 to 42 d of age.

The present study was carried out to evaluate dietary Mn requirements of broilers from 22 to 42 d of age using molecular biomarkers. Chickens were fed a conventional basal maize-soyabean meal diet supplemented with Mn as Mn sulphate in graded concentrations of 20 mg Mn/kg from 0 to 140 mg Mn/kg of diet for 21 d (from 22 to 42 d of age). The Mn response curves were fitted for ten parameters including heart Mn-containing superoxide dismutase (MnSOD) mRNA and its protein expression levels and the DNA-binding activities of specificity protein 1 (Sp1) and activating protein-2 (AP-2). Heart MnSOD mRNA and protein expression levels showed significant quadratic responses (P<0·01), and heart MnSOD activity showed a broken-line response (P<0·01), whereas Mn content and DNA-binding activities of Sp1 and AP-2 in the heart displayed linear responses (P<0·01) to dietary Mn concentrations, respectively. The estimates of dietary Mn requirements were 101, 104 and 94 mg/kg for full expressions of MnSOD mRNA level, MnSOD protein level and MnSOD activity in the heart, respectively. Our findings indicate that heart MnSOD mRNA expression level is a more reliable indicator than heart MnSOD protein expression level and its activity for the evaluation of Mn requirement of broilers, and about 100 mg Mn/kg of diet is required for the full expression of heart MnSOD in broilers fed the conventional basal maize-soyabean meal diet from 22 to 42 d of age.

Manganese elevates manganese superoxide dismutase protein level through protein kinase C and protein tyrosine kinase.

Three experiments were conducted to investigate the effects of inorganic and organic Mn sources on MnSOD mRNA, protein and enzymatic activity and the possible signal pathways. The primary broiler myocardial cells were treated with MnCl2 (I) or one of organic chelates of Mn and amino acids with weak, moderate (M) or strong (S) chelation strength for 12 and 48 h. Cells were preincubated with superoxide radical anions scavenger N-acetylcysteine (NAC) or specific inhibitors for MAPKs and protein tyrosine kinase (PTK) or protein kinase C (PKC) for 30 min before treatments of I and M. The MnSOD mRNA, protein and enzymatic activity, phosphorylated MAPKs or protein kinases activations were examined. The results showed that additions of Mn increased (P < 0.05) MnSOD mRNA levels and M was more effective than I. Additions of Mn elevated (P < 0.05) MnSOD protein levels and enzymatic activities, and no differences were found among I and M. Addition of NAC did not decrease (P > 0.05) Mn-induced MnSOD mRNA and protein levels. None of the three MAPKs was phosphorylated (P > 0.05) by Mn. Additions of Mn decreased (P < 0.05) the PTK activities and increased (P < 0.05) the membrane PKC contents. Inhibitors for PTK or PKC decreased (P < 0.05) Mn-induced MnSOD protein levels. The results suggested that Mn-induced MnSOD mRNA and protein expressions be not related with NAC, and MAPK pathways might not involve in Mn-induced MnSOD mRNA expression. PKC and PTK mediated the Mn-induced MnSOD protein expression.

Novel Hybrid Peptide Cecropin A (1-8)-LL37 (17-30) with Potential Antibacterial Activity.

Hybridizing different antimicrobial peptides (AMPs) is a particularly successful approach to obtain novel AMPs with increased antimicrobial activity but minimized cytotoxicity. The hybrid peptide cecropin A (1-8)-LL37 (17-30) (C-L) combining the hydrophobic N-terminal fragment of cecropin A (C) with the core antimicrobial fragment of LL37 (L) was designed and synthesized. C-L showed higher antibacterial activity against all indicator strains than C and L, and no hemolytic activity to sheep erythrocytes was observed. C-L kills bacterial cells and causes disruption of surface structure, as determined by scanning electron microscopy. Synergistic effects were observed in the combination of C-L with several antibiotics (chloramphenicol, thiamphenicol, or neomycin sulfate) against Escherichia coli and Staphylococcus aureus.

Expression of the Thermobifida fusca xylanase Xyn11A in Pichia pastoris and its characterization.

BACKGROUND: Xylan is a major component of plant cells and the most abundant hemicellulose. Xylanases degrade xylan into monomers by randomly cleaving ß-1,4-glycosidic bonds in the xylan backbone, and have widespread potential applications in various industries. The purpose of our study was to clone and express the endoxylanase gene xynA of Thermobifida fusca YX in its native form and with a C-terminal histidine (His) tag in Pichia pastoris X-33. We analyzed and compared these two forms of the protein and examined their potential applications in various industries. RESULTS: The xynA gene from T. fusca YX was successfully cloned and expressed using P. pastoris X-33. We produced a recombinant native form of the protein (rXyn11A) and a C-terminal His-tagged form of the desired protein (rXyn11A-(His)6). The specific activities of rXyn11A and rXyn11A-(His)6 in culture supernatants approached 149.4 and 133.4 U/mg, respectively. These activities were approximately 4- and 3.5-fold higher than those for the non-recombinant wild-type Xyn11A (29.3 U/mg). Following purification, the specific activities of rXyn11A and rXyn11A-(His)6 were 557.35 and 515.84 U/mg, respectively. The specific activity of rXyn11A was 8% higher than that of rXyn11A-(His)6. Both recombinant xylanases were optimally active at 80°C and pH 8.0, and exhibited greater than 60% activity between pH 6-9 and 60-80°C. They exhibited similar pH stability, while rXyn11A exhibited better thermostability; N-glycosylation enhanced the thermostability of both recombinant xylanases. The products of beechwood xylan hydrolyzed by both xylanases included xylobiose, xylotriose, xylotetraose and xylopentaose. CONCLUSIONS: The C-terminal His tag had adverse effects when added to the Xyn11A protein. The thermostability of both recombinant xylanases was enhanced by N-glycosylation. Their stabilities at a high pH and temperature indicate their potential for application in various industries.

Effects of Clostridium butyricum on antioxidant properties, meat quality and fatty acid composition of broiler birds.

BACKGROUND: Consumers are becoming increasingly interested in food containing high concentration of polyunsaturated fatty acids (PUFA). PUFA are considered as functional ingredients to prevent cardiovascular disease. The present study aimed to evaluate the effects of Clostridium butyricum on antioxidant properties, meat quality and fatty acid composition of broilers. METHODS: A total of 320 one-day-old Arbor Acres male chicks were randomly assigned to one of five treatments with eight replicates and fed a antibiotic-free basal corn-soybean meal diet (control) or the basal diet supplemented with either 2.5 × 10(8) (CB1), 5 × 10(8) (CB2) or 1 × 10(9) (CB3) cfu of C. butyricum/kg or 150 mg of aureomycin/kg (antibiotic) for 42 days. RESULTS: The results showed that chicks fed diets supplemented with C. butyricum had higher (P < 0.05) superoxide dismutase activity and lower (P < 0.05) malondialdehyde concentration in liver compared with those in the control group. Broilers had lower (P < 0.05) cholesterol content of serum in either CB2 or CB3 treatment at day 21 and in the C. butyricum-supplemented groups at day 42 than those in the control group. Chicks fed CB3 diet had lower (P < 0.05) percentage of abdominal fat and higher (P < 0.05) breast muscle yield than those in the control and antibiotic groups. The supplementation of C. butyricum increased (P < 0.05) the concentrations of C20:1n-9, C20:2n-6, C20:3n-6, C20:3n-3, C20:4n-6, C20:5n-3, C22:6n-3 and total PUFA as well as ratio of PUFA to saturated fatty acids in breast muscle and the contents of C18:2 t-9, t-12, C20:3n-6, C20:3n-3 and C20:5n-3 in thigh muscle. CONCLUSIONS: Supplementation of C. butyricum promotes hepatic antioxidant status, decreases cholesterol content of serum and percentage of abdominal fat, and improves meat quality and fatty acid composition of broiler birds. The results from the present study indicate that the increased PUFA concentrations in meat of broilers fed C. butyricum might be attributable to enhanced antioxidant activity.

Design, characterization and expression of a novel hybrid peptides melittin (1-13)-LL37 (17-30).

Hybridizing of different antimicrobial peptides (AMPs) has been a common practice for obtaining novel hybrid AMPs with elevated antibacterial activity but minimized cytotoxicity. The hybrid peptides melittin (1-13)-LL37 (17-30) (M-L) combining the hydrophobic N-terminal fragment of melittin (M) with the core antibacterial fragment of LL37 (L), was designed for the first time to explore its antibacterial activity and hemolytic activity against bacteria and sheep erythrocyte respectively. Results showed that M-L had an even more potent antibacterial activity against all indicator strains (especially gram-positive bacteria) than M and L, whereas didn't exhibit hemolytic activity to sheep erythrocytes, implying M-L can be served as a potential therapeutic drug to substitute traditional antibiotics. However the high expense of biosynthesis limited its further research, therefore fusion expression of M-L was carried out in Escherichia coli (E. coli) for overproducing the hybrid peptide so as to solve the problem. The DNA sequence encoding M-L with preferred codons was cloned into the pET-SUMO vector for protein expression in E. coli BL21 (DE3). After IPTG induction, approximately 165 mg soluble fusion protein SUMO-M-L was recovered per liter supernatant of the fermentation ultrasonic lysate using Ni-NTA Sepharose column (92 % purity). And 23 mg recombinant M-L was obtained per liter culture after cleavage of SUMO protease and purification of Ni-NTA Sepharose column. In sum, this research not only supplied an effective approach for overproducing hybrid peptide M-L, but paved the way for its further exploration on pharmaceutical potential and medical importance.

Distribution and health risk of chromium in wheat grains at the national scale in China.

Chromium (Cr) pollution may threaten food safety in China. In this study, the concentration, pollution level, distribution, and non-cancer risk of Cr in wheat grains grown in 186 areas across 28 provinces in China were investigated. Results indicated that mean concentration of Cr was 0.28 ± 2.5 mg/kg, dry mass (dm). Of the samples, 7.5 % were found to be polluted with Cr. The mean concentrations were in the following order: Northwest > Northeast > South > East > North > Southwest > Central China. Based on deterministic models, mean hazard quotient (HQ) values for adult males, adult females, and children were 0.11 ± 3.4, 0.11 ± 3.4, and 0.13 ± 3.5, respectively with < 6 % of HQ values ≥ 1. Eleven sites in northern China were identified as hotspots, whereas Gansu Province and Northwestern China were labeled as priority provinces and regions for risk control. The mean HQ values estimated by probabilistic risk assessment were two times greater than those estimated using deterministic models. The risk probabilities for adult males, adult females, and children were 4.81 %, 3.78 %, and 6.55 %, respectively. This study provides valuable information on Cr pollution in wheat grains and its risks at a national scale in China.

Predicting metabolizable energy of soybean meal and rapeseed meal from chemical composition in broilers of different ages.

This study determined metabolizable energy (ME) and developed ME prediction equations for broilers based on chemical composition of soybean meal (SBM) and rapeseed meal (RSM) using a 2 × 10 factorial arrangement of age (11 to 14 or 25 to 28 d of age) and 10 sources of each ingredient. Each treatment contained 6 replicates of 8 broilers. The ME values were determined by total collection of feces and urine. Principal components analysis (PCA) of the chemical composition clearly revealed distinct differences in SBM and RSM based on a principal components (PC) score plot. The nitrogen-corrected apparent metabolizable energy (AMEn) of SBM was higher in broilers from 25 to 28 than 11 to 14 d of age (P = 0.013). Interactions between broiler age and ingredient source affected apparent metabolizable energy (AME) of SBM and ME of RSM (P < 0.05). The ME of SBM in 11 to 14 and 25 to 28-day-old broilers were estimated by crude protein (CP) content (R2≥ 0.782; SEP ≤ 83 kcal/kg DM; P < 0.001). The AME and AMEn of RSM in 11 to 14-day-old broilers were estimated by ether extract (EE), ash and acid detergent fiber (ADF) (R2 = 0.897, SEP = 106 kcal/kg DM; P = 0.002), and by EE and ash (R2 = 0.885, SEP = 98 kcal/kg DM; P = 0.001), respectively. The AME and AMEn of RSM in 25 to 28-day-old broilers were estimated by ash and ADF (R2 = 0.925, SEP = 104 kcal/kg DM; P < 0.001) and by ash and neutral detergent fiber (NDF) (R2 = 0.921, SEP = 91 kcal/kg DM; P < 0.001), respectively. These results indicate that ME of these 2 plant protein ingredients are affected interactively by chemical composition and age of broilers. This study developed robust, age-specific prediction equations of ME for broilers based on chemical composition for SBM and RSM. Overall, ME values can be predicted from CP content for SBM, or EE, ash, ADF, and NDF for RSM.

Zinc alleviates thermal stress-induced damage to the integrity and barrier function of cultured chicken embryonic primary jejunal epithelial cells via the MAPK and PI3K/AKT/mTOR signaling pathways.

Zinc (Zn) could alleviate the adverse effect of high temperature (HT) on intestinal integrity and barrier function of broilers, but the underlying mechanisms remain unclear. We aimed to investigate the possible protective mechanisms of Zn on primary cultured broiler jejunal epithelial cells exposed to thermal stress (TS). In Exp.1, jejunal epithelial cells were exposed to 40℃ (normal temperature, NT) and 44℃ (HT) for 1, 2, 4, 6, or 8 h. Cells incubated for 8 h had the lowest transepithelial resistance (TEER) and the highest phenol red permeability under HT. In Exp.2, the cells were preincubated with different Zn sources (Zn sulfate as iZn and Zn proteinate with the moderate chelation strength as oZn) and Zn supplemental levels (50 and 100 µmol/L) under NT for 24 h, and then continuously incubated under HT for another 8 h. TS increased phenol red permeability, lactate dehydrogenase (LDH) activity and p-PKC/PKC level, and decreased TEER, cell proliferation, mRNA levels of claudin-1, occludin, zona occludens-1 (ZO-1), PI3K, AKT and mTOR, protein levels of claudin-1, ZO-1 and junctional adhesion molecule-A (JAM-A), and the levels of p-ERK/ERK, p-PI3K/PI3K and p-AKT/AKT. Under HT, oZn was more effective than iZn in increasing TEER, occludin, ZO-1, PI3K, and AKT mRNA levels, ZO-1 protein level, and p-AKT/AKT level; supplementation with 50 µmol Zn/L was more effective than 100 µmol Zn/L in increasing cell proliferation, JAM-A, PI3K, AKT, and PKC mRNA levels, JAM-A protein level, and the levels of p-ERK/ERK and p-PI3K/PI3K; furthermore, supplementation with 50 µmol Zn/L as oZn had the lowest LDH activity, and the highest ERK, JNK-1, and mTOR mRNA levels. Therefore, supplemental Zn, especially 50 µmol Zn/L as oZn, could alleviate the TS-induced integrity and barrier function damage of broiler jejunal epithelial cells possibly by promoting cell proliferation and tight junction protein expression via the MAPK and PI3K/AKT/mTOR signaling pathways.