Two experiments were performed to evaluate the effects of partial replacement of Tifton hay by Miúda cactus cladodes (Nopalea) or Orelha de Elefante Mexicana (O.E.M.) cactus cladodes (Opuntia) on serum and liver concentrations of iron (Fe), copper (Cu), zinc (Zn), and manganese (Mn) in feedlot small ruminants. The experiment 1 (Exp. 1) lasted 86 days, and thirty-six male Santa Inês lambs (22.0 ± 2.9 kg initial body weight-IBW) were used. In experiment 2 (Exp. 2), lasting 100 days, thirty-six male goats of undefined breed (19.0 ± 2.8 kg IBW) were used. In both studies, the animals were distributed in a completely randomized design, with three treatments (diet control-without cactus; and diets with hay partially replaced by Miúda or O.E.M. cactus cladodes) and twelve replicates. Blood samples were collected to quantify serum micromineral levels, and at the end of the feedlot periods, sheep and goats were slaughtered and liver fragments were collected for micromineral dosage. In Exp. 1, lambs fed Nopalea cactus cladodes diet showed greater hepatic Cu accumulation (441.87 mg/kg DM; P = 0.027). The diets containing cactus cladodes tended to increase serum levels of Cu (P = 0.075) and Zn (P = 0.058). In Exp. 2, goats fed diet containing Opuntia cactus cladodes presented higher serum levels of Fe (P = 0.024) and Cu (P = 0.012). In conclusion, the partial replacement of Tifton hay by cactus cladodes increases hepatic concentrations of Cu in lambs and serum levels of Fe and Cu in goats.
Keywords: Blood; Hepatic accumulation; Small ruminants; Spineless cactus; Trace mineral.
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