Keratinase improves the growth performance, meat quality and redox status of broiler chickens fed a diet containing feather meal.

The objective of this study was to assess the effects of dietary supplementation of keratinase on the production of broilers fed a diet containing feather meal. A total of 162 1-d-old Cobb 500 male broiler (n = 9 cages/diet with 6 chicks/cage) were randomly allocated to 3 dietary treatments. The broilers were fed a corn-soybean-feather meal based diet (BD), or BD supplemented with keratinase at 100,000 or 200,000 U/kg for 6 weeks. Compared to the control, dietary supplementation with 200,000 U/kg keratinase increased (P < 0.05) body weight gain (3.6-4.3%) and reduced feed conversion ratio (2.4-5.6%) during the various experimental periods, and also improved (P < 0.05) apparent total tract digestibility of ash and calcium by 45.0% and 8.8%, respectively. Meanwhile, dietary supplementation of keratinase at 100,000 U/kg reduced (P < 0.05) the drip loss (29.2%), while 200,000 U/kg keratinase supplementation increased (P < 0.05) the pH value (1.6%) at 45 min and decreased (P < 0.05) the lightness (L* value; 13.6%) and drip loss (22.1%) of pectoral muscle. Moreover, dietary supplementation of keratinase at both levels of 100,000 and 200,000 U/kg increased (P < 0.05) Glutathione peroxidase activity (82.5-87.5%) and decreased the Malondialdehyde concentration (14.5-18.3%) in the pectoral muscle. In conclusion, dietary supplementation of keratinase at 200,000 U/kg can improve the performance, meat quality, apparent total tract digestibility of nutrients, and redox status of broiler chickens fed a diet containing feather meal.

[Effects of Tripterygium hypoglaucum (level) Hutch extraction on regulatory T cells in mice after allogeneic bone marrow transplantation].

OBJECTIVE: To study the effect of Tripterygium hypoglaucum (level) Hutch (THH) extraction in alleviating the graft-versus-host disease (GVHD) in mice after allogeneic bone marrow transplantation and to explore its mechanism. METHODS: Mixture of 2 x 10(7) bone marrow cells and 2 x 10(7) spleen cells obtained from C57BL/6 mouse were transplanted into the myelo-ablative irradiated inbred BALB/c mouse (H-2(d)). The experimental mice were designed into 4 groups: the control group (A), the Cyclosporine A (CsA) group (B), the THH group (C), and the CsA + THH group (D). Condition of GVHD and transplanted chimera were observed, percentage of CD4(+)CD25(+) T cell in peripheral blood were detected by flow cytometry, and the expression of Foxp3 mRNA in splenocyte at different time points were determined by real-time FQ-PCR. RESULTS: CD4(+)CD25(+) T cell in Group B, C and D increased from the 10th day, peaked on the 15th day, descended after then, but the level in Group D maintained higher than that in the other three groups (P<0.05). Expression of Foxp3 mRNA in recipients' splenocytes increased gradually, reached peak on the 15th day and followed with gradual decreasing, the highest peak and the slowest decreasing was shown in Group D, so the level was still rather higher in Group D on the 30th day. The survival time in the three treated group (B, C and D) were all longer than that in the control group A (P<0.05). GVHD signs and pathologic changes in the three treated groups were milder than in the control group. Allogeneic chimerism rates (H-2(d)) in all groups were over 95%. CONCLUSION: THH could prevent GVHD in mice after allogeneic bone marrow transplantation, and prolong their survival time, the mechanism is possibly related with its immunosuppressive effect in raising CD4(+)CD25(+) T cells and promoting the Foxp3 mRNA expression. THH combining with small dose CsA shows synergic effect in preventing GVHD.

[Experimental study of Tripterygium hypoglaucum (level) Hutch on preventing acute graft-versus-host disease in bone marrow transplantation mice].

OBJECTIVE: To evaluate the effects of Tripterygium hypoglaucum (level) Hutch (THH) on cytokine production in acute graft-versus-host disease (aGVHD)mice and explore the mechanisms. METHODS: 2 x 10(7) bone marrow cells mixed with 2 x 10(7) spleen cells from the same C57BL/6 mouse were transplanted into the myeloablative irradiated inbred BALB/c mouse to establish a aGVHD model. The experiments were designed as follows: control group (group A), CsA prophylaxis group (group B), THH prophylaxis group (group C), and combined THH with CsA prophylaxis group (group D). aGVHD was assessed by histologic changes of skin, liver and intestines. Chimerism was detected by H-2b molecular expression on recipient mice bone marrow cells with flow cytometer. Serum concentrations of IFN-gamma, IL-4 and IL-10 were determined by ELISA. RESULTS: The serum concentrations of IFN-gamma in group B, C, D were significantly lower than that in group A, while those of IL-10 was significantly higher than that in group A (P < 0.05). There was no changes in concentration of IL-4 in all the groups (P > 0.05). The median survival time for group A was nine days, while that of group B, C, D each was more than 30 days being significantly longer than that of group A (P < 0.05). The recipient mice of group A displayed significant clinical symptoms of GVHD, and died within 20 days; whereas those of group B, C, D showed only ruffled fur and uplift posture. Histologic changes of liver and intestines in group B and C displayed a few lymphocytes infiltration while the histologic morphology of skin, liver and intestines in the survived mice of group D was normal. Allogeneic chimerism rates of group B, C, D at day 30 after allo-BMT were (99.18 +/- 0.58)%, (97.68 +/- 0.59)%, and (99.15 +/- 0.11)%, respectively. CONCLUSION: THH could regulate the production of cytokines and prevent aGVHD. THH and CsA at low dose combination showed synergic effect in preventing aGVHD.