Dietary supplemented antimicrobial peptide microcin J25 improves the growth performance, apparent total tract digestibility, fecal microbiota, and intestinal barrier function of weaned pigs.

Microcin J25 (MccJ25) is an antimicrobial peptide produced by a fecal strain of Escherichia coli containing 21 AA. This study was performed primarily to evaluate the effects of MccJ25 as a potential substitute for antibiotics (AB) on growth performance, nutrient digestibility, fecal microbiota, and intestinal barrier function in weaned pigs. In the present study, 180 weaned pigs (7.98 ± 0.29 kg initial BW) were randomly assigned to 1 of 5 treatments, including a basal diet (CON) and CON supplemented with AB (20 mg/kg colistin sulfate; ABD) or 0.5, 1.0, and 2.0 mg/kg MccJ25. On d 0 to 14, dietary supplementation with MccJ25 and ABD had positive effects on ADG, ADFI, diarrhea incidence, and G:F ( < 0.05). Pigs fed the 2.0 mg/kg MccJ25 diet had greater ADG ( < 0.05) and marginally greater G:F ( < 0.10) compared with pigs fed the ABD diet. Compared with the CON diet, the 2.0 mg/kg MccJ25 diet sharply improved ( < 0.05) ADG and G:F and decreased ( < 0.05) diarrhea incidence (d 15 to 28 and d 0 to 28). Apparent digestibility of nutrients in pigs fed 1.0 and 2.0 mg/kg MccJ25 was improved ( < 0.05) compared with that of pigs fed CON and ABD. The serum cytokines IL-6 and IL-1ß and tumor necrosis factor-α levels in pigs fed MccJ25 were greater than in pigs fed CON ( < 0.05). Additionally, the IL-10 concentration in pigs fed MccJ25 was sharply increased ( < 0.05) compared with that of pigs fed CON. Pigs fed 1.0 and 2.0 mg/kg MccJ25 diets had remarkably decreased lactate, diamine oxidase, and endotoxin concentrations and fecal numbers ( < 0.05) and improved fecal and numbers ( < 0.05). Compared with the ABD diet, the diet containing 2.0 mg/kg MccJ25 did not increase lactate, diamine oxidase, and endotoxin (d 14) concentrations ( < 0.05) or decrease the and (d 28) numbers ( < 0.05). The diets containing 1.0 and 2.0 mg/kg MccJ25 and ABD (d 28) improved lactate concentration and short-chain fatty acid concentrations, including acetate, propionate, and butyrate, in feces ( < 0.05). Moreover, the pigs fed 2.0 mg/kg MccJ25 had greater lactate, butyrate (d 14), and propionate concentrations than the pigs fed the ABD diet ( < 0.05). In conclusion, dietary supplemented MccJ25 effectively improved performance, attenuated diarrhea and systematic inflammation, enhanced intestinal barrier function, and improved fecal microbiota composition of weaned pigs. Therefore, MccJ25 could be a potential effective alternative to AB for weaned pigs.

Effects of neonatal oxytocin treatment on aggression and neural activities in mandarin voles.

Neonatal manipulation of oxytocin (OT) has long-term effects on behavior and physiology. Here we test the hypothesis that neonatal OT treatment can affect the subsequent expression of intrasexual aggression partly by reprogramming the neural activities of relevant brain regions. To test this hypothesis, mandarin voles (Lasiopodomys mandarinus) received OT or isotonic saline treatment within 24 h of birth. At about 75 days of age, aggressive behaviors and Fos expression in different brain regions were tested. The results indicate that the (1) level of intrasexual aggression was higher and other social contact was lower in SAL-treated sexually naïve males than in females and; (2) OT-treated females showed a greater increase in aggressive behaviors and Fos expression only after exposure to a male than SAL-treated females, but there were no significant changes in aggressive behaviors in males. These results demonstrate a sexual difference in aggression, and that neonatal exposure to OT may increase aggression in female mandarin voles. These effects may be based on changes in neural activities of relevant brain regions including the bed nucleus of the stria terminalis (BNST), lateral septal nucleus (LS), medial preoptic area (MPOA), the paraventricular nucleus of the hypothalamus (PVN), supraoptic nucleus (SON), mediodorsal thalamic nucleus (MD), ventromedial nucleus of hypothalamic (VMH), the medial amygdala (MeA) and central amygdala (CeA).

[Screening of steroidal saponins from the bulbs of Lilium brownii var. colchesteri by combination of high performance liquid chromatography-electrospray ionization mass spectrometry and electron impact mass spectrometry].

With the combination of high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC/ESI-MS) and electron impact mass spectrometry (EI-MS), two steroidal saponins, one compound containing three glycosyls and tigogenin and the other one containing three glycosyls and diosgenin, from the bulbs of Lilium brownii var. calchesteri in China have been screened. In the method, on-line HPLC/ESI-MS allows us to obtain rapidly useful information about the molecular weight and the glycosyl chain of glycoside without the necessity of isolating individual compounds, but little information about steroidal sapogenins. Just with 1 mg to 2 mg of pure sample, off-line EI-MS allows us to acquire useful information about a steroidal sapogenin of saponins, but it is difficult to obtain the molecular ion peak. The combination of HPLC/ESI-MS and EI-MS is well suitable for rapidly screening steroidal saponins from plants.

[Contraction stimulates incorporation of 3H-leucine and cell growth in cultured neonatal rat ventricular myocytes].

To determine whether contraction could influence cell growth, the rate of protein synthesis (3H-leucine incorporation) and cell diameter and volume were measured in cultured neonatal rat cardiac myocytes beating spontaneously or arrested by high potassium. In medium supplemented with 10% calf serum, the 3H-leucine incorporation for 24 h in contracting myocytes (CMC) was significantly higher by 14.2% than that in quiescent myocytes (QMC), i.e. 1,229 +/- 29 cpm/10(5) cells vs. 1,076 +/- 60 cpm/10(5) cells (P < 0.01, n = 5 for each group). The cell diameter and cell volume in QMC group were respectively 15.14 +/- 0.42 microns and 1,842 +/- 123 microns3, while in the CMC group the corresponding figures reached to 16.82 +/- 0.64 microns3 and 2,495 +/- 210 microns3, increased by 11.1% and 35.5% respectively (P < 0.01, n = 6 for each group). With prolongation of culture time, the differences in these parameters between CMC and QMC became even more significant. In all these experiments, there was no significant difference in cell number between the two groups (P > 0.05). It is concluded that contraction per se can accelerate protein synthesis and cell growth in neonatal rat ventricular myocardium.