BACKGROUND: The effects of inorganic trace minerals (ITM) replaced by low-dose glycine-complexed trace minerals (GCM) on growth, serum parameters, immunity, intestinal morphology, and mineral excretion in piglets were investigated. One hundred and twenty-eight weaned piglets (14.18 ± 0.33kg body weight (BW)) were randomly assigned to 4 treatments with 4 replicates, 8 piglets per replicate. Treatments consist of: (T1) basal diet + 100% inorganic trace mineral (ITM) as the control group (20 ppm Cu, 150 ppm Fe, 150 ppm Zn, and 30 ppm Mn from sulfates); (T2) basal diet + 50% ITM (Cu, Fe, Zn, and Mn from sulfates, 50% of control) + 50% organic trace minerals (OTM, Cu, Fe, Zn, and Mn from glycine complexed trace minerals (GCM), 50% of control); (T3) basis diet + 50% OTM from GCM; (T4) basal diet + 70% OTM from GCM. The feeding period lasted 28 d and was divided into 2 stages (0 to 14 d and 15 to 28 d). After feeding trial , 6 pigs per treatment were randomly selected to slaughter for sampling.
RESULTS: Average daily gain, feed intake, and G:F were not affected by dietary treatments during the overall period. During the second, and the overall feeding phases, the digestibility of Zn and Fe in T3 and T4 was higher than that of T1 ( P < 0.05). The concentration of serum ferritin in T2 was significantly higher than T3 and T4. Serum immunoglobulin A concentration in the ileal mucosa of T2 was higher than that of T1 ( P < 0.05), and the higher duodenum villus height was observed in T4 compared with the rest treatments ( P < 0.05). The lowest trace mineral excretion was overserved in T3 ( P < 0.01); in addition, the urinary concentrations of Zn and Fe in T2 were lower than that in T1 ( P < 0.05).
CONCLUSION: These results indicate that GCM have higher bioavailability than ITM, and that supplementation of low-dose GCM to replace full dose ITM could reduce mineral excretion without affecting performance, blood profiles, immune responses, and intestinal morphology in piglets.