The Effect of Dietary Organic Copper and Zinc Trace Minerals on some Yield and Mineral Levels and Histological Structure of Testes

Abstract

This study aims to investigate the effects of providing Cu and Zn minerals with an organic structure reduced by 25% compared to the recommended (NRC) inorganic value on parameters such as the age at which lambs achieve 50% sperm motility yield, some developmental parameters, testis histology, as well as serum, wool, and fecal mineral levels in lambs. The study involved 12 male lambs in the T1 group (organic minerals) and 11 in the T2 group (inorganic minerals) of the Kıvırcık breed. Lambs received minerals from mothers during the last month of fetal period and suckling, continuing individual feeding post-weaning. During individual feeding, T1 received 5.25 mg/kg DM copper-chelate and 15.0 mg/kg DM zinc-chelate, while T2 received 7 mg/kg DM copper-sulfate and 20 mg/kg DM zinc-sulfate. The mothers received identical mineral amounts in the last month of pregnancy and lactation. The ewes birthed offspring solely for the supply of experimental groups. Lambs, averaging about 18.5 kg, underwent bi-weekly electroejaculation, concluding the trial for those with 50% semen motility. Statistical analyses were carried out using the GLM method. No differences were observed between groups in the average age at which lambs achieve 50% sperm motility, live weight, scrotum, and testicular measurements at this age (P > 0.05). Histological analyses revealed no difference in tubule area between T1 and T2 groups (P > 0.05), but tubular epithelium height was greater in T1 (P < 0.01). End-of-trial serum copper, as well as weaning day and end-of-trial serum and fleece zinc mean values, did not differ between groups (P > 0.05). However, T1 had higher mean values for serum Cu on the weaning day (P < 0.01), fleece copper on the weaning day (P < 0.05) and at the end of the trial (P < 0.001). Additionally, the T1 group exhibited lower mean levels of fecal copper (P < 0.05) and fecal zinc (P < 0.001). In conclusion, despite organic copper and zinc levels being 25% lower in the examined parameters, comparable or improved results were achieved with inorganic copper and zinc.