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The objective of this study was to evaluate the effects of two sublethal doses (4 and 20 mg/kg live weight (LW); every other day) of gossypol on semen and hormonal characteristics of male rabbits. The experiment lasted 16 weeks and included two periods: a treatment period (first 8 weeks) where the animals were given the test materials, and a recovery period (second 8 weeks) where drugs were withdrawn. Results showed that LW and respiration rate (RR) decreased ( P , 0·05) among animals that received gossypol, while rectal temperature increased ( P , 0·05). Animals in gossypol treatment groups had decreased ( P , 0·05) blood plasma levels of tri-iodothyronine (T 3 ) and testosterone. This was accompanied by reductions ( P , 0·05) in sperm concentration, total sperm output, percentage incidence of forward motility, total functional sperm fraction and semen initial fructose concentration. Gossypol however increased ( P , 0·05) reaction time (i.e. decreased libido), percentages of dead sperm and abnormal sperm (AbSp) and altered acrosomes. Estimated weights of testes and semen ejaculate volume increased ( P , 0·05) possibly due to increased water retention. Values of LW, RR, AbSp, and blood plasma T 3 and testosterone returned to control levels after withdrawal of gossypol, while the effect of this drug on other parameters continued during the recovery period.

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The objective of this study was to evaluate the reproductive toxicity of gossypol and the possible counteracting effect of selenium supplementation in rams. Twenty-five mature crossbred (Barki × Rahamni) rams were randomly divided into 5 equal groups. The first group served as a control (no gossypol in diet). The second and third groups received diets containing free gossypol of 9 and 14 mg·kg(-1) BW·d(-1)(low level and high level of gossypol), respectively. The fourth and fifth groups received the same diets given to the second and third groups, respectively, with an oral administration of 1 mg selenium (as sodium selenite) daily for each animal. Results showed reductions in ejaculate volume (P = 0.028), percentage of dead sperm (P = 0.003), total functional sperm fraction (P < 0.001), and blood serum concentration of testosterone (P < 0.001) in the presence of both levels of gossypol inclusion. Furthermore, high level of gossypol reduced forward motility (P < 0.001) and semen initial fructose concentration (P = 0.002) and increased abnormal-head sperm (P = 0.003) and blood serum concentration of triiodothyronine (P = 0.006). Regardless of selenium supplementation, increasing level of free gossypol in diet resulted in a significant decrease in the percentage of forward motility (P = 0.037) and significant increases in the mean values of sperm concentration (P < 0.001), total sperm output (P = 0.002), percentage of total abnormal sperm (P = 0.058), and abnormal-head sperm (P = 0.016). On the other hand, regardless of levels of gossypol inclusion, selenium supplementation resulted in significant increases in libido (P < 0.001), mean values of ejaculate volume (P < 0.001), percentage of forward motility (P = 0.019), total sperm output (P < 0.001), total functional sperm fraction (P < 0.001), semen initial fructose concentration (P = 0.031), and blood serum concentrations of both testosterone and triiodothyronine (P < 0.001). In conclusion, free gossypol in diet induced adverse effects on semen quality in rams, but selenium supplementation successfully counteracts most of the hazardous effects of gossypol on semen characteristics.