RESUMEN
To investigate the effects of dietary fat sources on histological structures of testis in Zandi rams. Field trial on the basis of completely randomized design [CRD]. Eight 2.5 years old mature Zandi rams. Four experimental feed with different fat sources were used in four groups: without fat supplementation [control or diet 1], supplementation with 4% calcium soaps of fatty acids from tallow [diet 2], supplementation with 4% calcium soaps of fatty acids from soybean oil [diet3] and supplementation with 2% calcium soaps of fatty acids from tallow plus 2% calcified fatty acids from soybean oil [diet 4]. Values of Seminiferous tubule diameter, number of leydig cells, sertoli cells, spermatogonia, primary spermatocyte and spermatid were determined. Values of testis histological structures were compared by Duncan procedure with GLM. Results showed that ram's reproduction performance and testis histological structures were affected by nutritional conditions of animal [p<0.05]. Moreover, source of dietary fatty acids had significant effect on testis histological structures. Using soybean oil resulted in a significant increase in the seminiferous tubule diameter, seminiferous tubule lumen diameter and number of leydig cell, sertoli cell, spermatogonia and primary spermatocyte [p<0.05]