Physiological and Histological Responses of Awassi Lambs to High Dietary Organic Copper Supplementation

This study investigated the effects of high dietary organic copper supplementation on growth performance, mineral metabolism and organ histology in male Awassi lambs. Fifteen lambs with similar body weight (16 ± 1.53 kg) were assigned to three groups: a control group (T1) receiving a basal diet, and two treatment groups (T2 and T3) supplemented with 0.5 g and 1 g of organic copper per kg DM, respectively. The total dietary copper concentrations were 6.18, 81.68 and 156.75 ppm in T1, T2, and T3 groups, respectively. The basal diet, composed of soybeans, wheat, and barley, provided 2.4 Mcal/kg metabolizable energy and 14% crude protein. High dietary copper supplementation had no significant impact on growth performance and body biometric measurements. Testicular length was increased in T3 lambs. Mineral analysis showed increased hepatic copper concentrations in T2 and T3 lambs. Kidney copper levels remained within normal ranges, while renal zinc concentrations declined in T2 and T3 lambs. Gene expression analysis demonstrated upregulation of <i>ATP7A</i> and <i>ATP7B</i> genes in T3 lambs, indicating a cellular adaptation to elevated copper levels, while <i>IGF1</i> expression remained unchanged. Histological assessments, however, revealed hepatic and renal changes in T3 lambs. Overall, high dietary organic copper supplementation, particularly at 1 g Cu/kg DM, increases copper retention and may support reproductive health in Awassi lambs. However, excessive intake poses risks of liver and kidney damage, highlighting the need for careful dietary management.