Effects of feeding with different sources of zinc supplements on seminal plasma enzymatic and ionic changes in rainbow trout (Oncorhynchus mykiss) broodstock males

In the present study, the effects of feeding with different sources of zinc supplements including mineral, nanoparticulate, and organic forms on the enzymatic and ionic changes of seminal plasma in rainbow trout broodstocks were investigated. A total of 108 broodstock males with mean weight of 2138±93.45 g were fed during 16 weeks in four treatments with adding 40 mg. kg-1 of 1. Mineral zinc supplement, 2. Zinc nanoparticles supplement, 3. Organic zinc supplement, 4. Broodstocks fed with control diet with no adding of zinc supplement. According to the findings related to the effect of different rations on seminal plasma enzymes, the lowest levels of ALT, AST, LDH and SOD enzymes were recorded in fish fed with mineral zinc supplement. These values were significantly different compared to the control with the highest levels (p˂0.05). There was no significant difference in ALP value between different treatments (p>0.05). Catalase and glutathione peroxidase enzyme values were not significantly different between treatments (p>0.05). Regarding the effect of different zinc supplements on inorganic compounds of seminal plasma, it was observed that the phosphor ion was not affected by these supplements (p>0.05) but a comparison between magnesium and calcium mean values (2.63±0.37 mg/dl and 7.23±0.15 mg/dl, respectively) in different treatments indicated a significant increase of these ion values in fish fed with mineral zinc supplement compared to the control (p˂0.05). In conclusion, regarding the decreasing effect of mineral zinc on the transaminases values and its increasing effect on the inorganic compounds values of magnesium and calcium in seminal plasma, this essential micronutrient could be considered and further investigated as an appropriate dietary supplement for improving the sperm quality of rainbow trout male broodstock.