Sanguinarine instead of Tryptophan on Growth and Metabolism of Pig under Conditions of Lower‐protein Diets

The experiment was conducted to investigate the effect of sanguinarine on the growth performance of pigs under the conditions of lower‐protein diets. 192 healthy Duroc× Landrace×Large pigs with average body weight of 25 kg were randomly selected and allocated to 4 groups, 6 replicates in each group and 8 pigs in each replicate.The group I to IV were separately feeding with lower‐protein diet, lower‐protein without tryptophan diet, lower‐protein without tryptophan but with sanguinarine diet and basal diet. The experiment consisted of two stages according the weight about 25‐60 kg and 60‐100 kg. Results showed that: 1)There were no significant difference on growth performance of the whole period among each group ( P>0.05 ). 2) The serum tryptophan levels of group III was always higher than group II( P<0.05 ), but there was no significant difference between the four groups ( P>0.05 ). 3) Caecum sections' skatole was lowest in group III, but there was no significant difference among all the groups ( P>0.05 ). In the colon, the contents of skatole of group II and group III were significantly lower than groupIand group IV( P<0.05 ).The activity of tryptophan decarboxylase (TDC) in the jejunal and ileum which from group III was lower than group II ( P>0.05 ),and there were no significant difference among those groups. In general, the sanguinarine showed no difference on the growth performance of pigs. And sanguinarine couldn't affect the skatole which comes from the tryptophan metabolite. It showed that the sanguinarine could improve the content of tryptophan in the serum, and influence the activity of the tryptophan decarboxylase in pigs' gut, all this could be beneficial to the synthesis of protein.