Abstract: [Objective] To investigate the effects of dietary supplementation of Morinda officinalis How polysaccharides （MOP） on production performance, tibia index, tibial content of calcium ,phosphorus and ash, and serum electrolytes level in broilers with tibial dyschondroplasia （TD） induced by thiram. [Method] A total of 120 1-day-old healthy AA broilers were randomly divided into 3 groups with 4 replicates in each group and 10 broilers in each replicate. The broilers served as control （CON group） were fed with basal diet; the broilers used to establish TD model induced by thiram （TD group） were fed with basal diet at the initial period of the experiment, and then received dietary supplementation of 100 mg/kg thiram from the 4^th to 7^th day of the experiment; after receiving the same treatment with TD group, the broilers in MOP group were fed with basal diet supplemented with 400 mg/kg MOP from the 7^th to 15^th day of the experiment. [Result] Compared with the CON group, during the first 7 days of the experiment, the average feed intake and average daily gain of TD group was decreased significantly （P<0.05）, and the feed to gain ratio was increased （P>0.05）; in TD group, the tibial growth plate width and coefficient of growth plate width was increased significantly （P<0.05）, the tibial weight, length and ash content were decreased significantly （P<0.05）, and the tibial weight index was reduced （P>0.05） on the 7^th, 11^th and 15^th day of the experiment, in addition, the appearance of serum electrolyte disorder was also observed; compared with TD group, the MOP group had decreased feed to gain ratio （P>0.05）, significantly （P<0.05） decreased tibial growth plate width and coefficient of growth plate width, and significantly （P<0.05） increased tibial weight, length and weight index on the 11^th and 15^th day of the experiment; the tibial ash content of MOP group was increased significantly （P<0.05） on the 11^th day of the experiment; with the extension of the experimental period, the serum electrolytes level of the MOP group tended to balance. [Conclusion] Dietary supplementation of MOP can effectively alleviate and ameliorate the TD associated symptoms of broilers induced by thiram.

Key words: tibial dyschondroplasia, Morinda officinalis How polysaccharides, broiler, growth performance, tibial ash, calcium, phosphorus, electrolytes