Effects of dietary inclusion of fermented cottonseed meal on growth, cecal microbial population, small intestinal morphology, and digestive enzyme activity of broilers.

Two experiments were conducted to test the feeding value of fermented cottonseed meal (FCSM) in broilers. In experiment 1, 480 1-day-old male yellow-feathered broilers were allocated into 4 dietary treatments with 6 replicates (20 birds per replicate) to examine the effects of FCSM on the growth response of chickens. Experimental feeding was performed for 6 weeks in two phases (starter, days 0 to 21; finisher, days 22 to 42). FCSM was used at 0, 40, 80, and 120 g/kg levels to replace soybean meal in the basal diet. The dietary inclusion of 40 and 80 g/kg FCSM increased (quadratic (Q): p<0.01) the body weight gain of broilers in the starter and in the overall feeding periods. Experiment 2 determined the effect of FCSM on the cecal microbial populations, intestinal morphology, and digestive enzyme activity of broilers. The number of lactobacilli in the cecal digesta increased at day 21 (p<0.01) and day 42 (linear (L): p=0.01). Coliform bacteria counts decreased (L: p<0.05) with the increasing inclusion of FCSM at day 21. The inclusion of FCSM increased (L-Q: p<0.05) villus height in the duodenum and linearly elevated (p<0.05) villus height and the villus height to crypt depth ratio in the jejunum at day 21. Similar improvement (L: p<0.05) was noted in jejunal villus height at day 42. The inclusion of FCSM improved (p<0.05) the activities of amylase and protease at day 21, as well as protease at day 42. In conclusion, the appropriate inclusion of FCSM improves growth, cecal microflora, intestinal morphology, and digestive enzyme activity in yellow-feathered broilers.

Improvement of xylanase production by Aspergillus niger XY-1 using response surface methodology for optimizing the medium composition.

OBJECTIVE: To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation (SSF). METHODS: Statistical methodology including the Plackett-Burman design (PBD) and the central composite design (CCD) was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. RESULTS: Firstly, NaNO(3), yeast extract, urea, Na(2)CO(3), MgSO(4), peptone and (NH(4))(2)SO(4) were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization. Finally, the CCD and response surface methodology (RSM) were applied to determine the optimal concentration of each significant variable, which included urea, Na(2)CO(3) and MgSO(4). Subsequently a second-order polynomial was determined by multiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x(1) (urea)=0.163 (41.63 g/L), x(2) (Na(2)CO(3))=-1.68 (2.64 g/L), x(3) (MgSO(4))=1.338 (10.68 g/L) and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. CONCLUSION: By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization.