Effect of dietary Mintrex-Zn/Mn on performance, gene expression of Zn transfer proteins, activities of Zn/Mn related enzymes and fecal mineral excretion in broiler chickens

This study was to evaluate dietary Mintrex-Zn/Mn on growth performance, enzyme activ ities, and trace mineral absorption and utilization in 0-3-wk broilers. One hundred sixty day-old male broiler chickens were allotted to 4 dietary treatments with 5 replicate cage. of 8 birds. Broilers were fed maize-soybean basal diets containing zinc (Zn, 100 mg/kg) and manganese (Mn, 120 mg/kg) from sulphate salts, while three other treatments included 100%, 80%, and 60% of the basal dietary mineral (actually 70%, 56% and 42% of sulphate salt. based on 70% of sulphates would be available) from Mintrex-Zn/Mn, respectively. At the end of 3 weeks of age. the growth performance, mRNA abundance of Zn/Mn transfer pro teins in jejunum mucosa, enzyme activities of liver lactate dehydrogenase (LDH), glutamia oxalacetic transaminase (GOT) and glutamate-pyruvate transaminase (GPT), activities of serum alkaline phosphatase (ALP), Mn-superoxide dismutase (SOD), total superoxide dis mutase (T-SOD) and CuZn-SOD and bone mineralization were measured. Total collection procedure in the balance trial of excreta was done from the age of 20 to 23 days. The result showed that supplementation with 100% Mintrex-Zn/Mn significantly improved the aver age daily gain (ADG) (P<0.01) and decreased fecal mineral excretion (P<0.05) compared to inorganic supplementation, but did not affect Zn/Mn transfer proteins mRNA abundance( (P> 0.05). Supplementation with 80% Mintrex-Zn/Mn lowered serum ALP activity (P<0.05) however, it did not affect the growth performance, mRNA abundance of Zn/Mn transfe. proteins and bone mineralization in comparison to inorganic supplementation (P> 0.05) The decrease of excretion is mainly due to the reduction of dietary supplemental level on minerals. Supplementation with 80% Mintrex-Zn/Mn decreased Mn and Zn excretion in the feces (mg/kg diet) by 39.79% and 30.13% (P<0.001), respectively. Supplementation with 60% Mintrex-Zn/Mn significantly decreased ADG (P<0.01), the length of metatarsus, serrALP activities and mRNA expression of Zn transfer proteins but increased mortality and culling rate (P<0.05). There were no differences in activities of serum T-SOD, CuZn-SoD and Mn-SOD, and liver metabolic enzyme (LDH. GOT, and GPT) among inorganic versus Mintrex; Zn/Mn supplementations. This study suggested that using approximately 30-40% Mintrex; Zn/Mn could not substitute for the inorganic trace mineral. LDH, GOT, GFT may not be sen sitive variables to reflect the states of the Zn and Mn in the body. Supplementation with 80% Mintrex-Zn/Mn (56% of inorganic mineral level) had a better effect in reducing the fecal min eral excretion without compromise in the growth performance. Using relative mineral concentration in fecal material may overestimate the values of mineral reduction, and it would be more accurate to use trace mineral concentration per chick day or per kg diet intake. (C) 2011 Elsevier B.V. All rights reserved