This experiment was conducted to study the effect of different dietary protein sources and levels on digestive enzyme activity of intestinal tract and plasma total amino acid content in laying hens. Fifty hy-line variety brown laying hens aged of 68 weeks with similar body weight were divided into 5 groups with 10 replicates per group and 1 hen in each replicate. The experimental diets were prepared with different dietary crude protein (CP) sources and levels that based on corn-soybean diet, and the 5 groups were control group (CP 15.50%), high protein level group (CP 18.00%, HP), low protein level group (CP 13.09%, LP), rapeseed meal group (CP 15.50%, RM) and cottonseed meal group (CP 15.50%, CM), respectively. The experiment lasted for 8 days. The results showed that the chyme pH of intestinal tract in CM was significantly higher than that in control group (P<0.01); the activity of trypsin in LP group was significantly higher than those in CP, HP and CM (P<0.05), and the activities of amylase, maltase and lipase and total amino acids content of plasma and average daily gain were not significantly affected in the 5 groups (P＞0.05). In conclusion, diets supplemented with different sources and levels of protein can significantly affect the chyme pH of intestinal tract, but have no significant effect on the activities of most digestive enzymes, total amino acids of plasma and average daily gain in laying hens. ［Chinese Journal of Animal Nutrition, 2011, 23（7）：1233 -1238］
ZHAO Liyan,XIAO Jingjing,LIN Hai,JIAO Hongchao,SONG Zhigang
. Dietary Protein Sources and Levels Affect the Intestinal Digestive Enzyme Activity and Total Plasma Amino Acid Content in Laying Hens[J]. Chinese Journal of Animal Nutrition, 2011
, 23(07)
: 1233
-1238
.
DOI: 10.3969/j.issn.1006-267x.2011.07.023
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