Eighteen yearling beef bulls were used in a study to determine the effects of diets containing gossypol on spermatogenic tissues, Sertoli cells and Leydig cells. Bulls were randomly assigned to one of three (n = 6) isonitrogenous diet groups formulated from alfalfa hay and corn (gossypol-free control), control plus whole cottonseed and cottonseed hulls, or control plus cottonseed meal and cottonseed hulls as sources of gossypol. Testicular tissues collected were examined histologically, and tissues from bulls fed gossypol-free diets were compared with those fed diets containing cottonseed products. Following a 2-mo period (P1) when bulls were fed diets containing gossypol, one-half of the bulls were placed on a gossypol-free diet for an additional 2 mo (P2) to determine if gossypol effects were reversible. At the end of P1, bulls fed whole cottonseed and cottonseed meal had larger (P<0.01) lumens in their seminiferous tubules, decreased (P<0.001) wall thickness in their seminiferous tubules, and a reduced (P<0.0001) number of cell layers in their seminiferous tubles, when compared with bulls fed a gossypol-free diet. These histological changes indicate detrimental effects to the spermatogenic tissues and associated cells. Following the initial two months (P1) of receiving feed containing gossypol, herd mates that were fed a gossypol-free diet for 2 mo (P2) showed improvement in histological characteristics, indicating that gossypol-induced effects were partially reversible.

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