Effect of zinc mono glycinate and zinc proteinate on production performance, antioxidant profile, metallothionein gene expression and tibia bone parameters in commercial broiler chicken

Lonkar, V.D., Kadam, A.S., Jadhav, S.N., Srivastava, A.A., Choudhari, F.N., Dhore, N.C. and Shisodiya, M.R. 2024. Effect of zinc mono glycinate and zinc proteinate on production performance, antioxidant profile, metallothionein gene expression and tibia bone parameters in commercial broiler chicken. Indian Journal of Poultry Science, 59(1): 23–28.

An experiment was conducted for 3 5 days on Ven Cobb 430Y strain of broilers (n= 180, 3 replicates/group, each comprising 20 birds) to evaluate the effect of inorganic and organic forms of Zinc (Zn). The broilers were randomly divided into three groups viz., T1 (basal diet with inorganic Zn as Zinc Sulfate (ZnS) @ 80g/ton of feed), T2 (basal diet with organic Zn as Zinc Mono Glycinate (ZnGly) @ 27.5 g/ton of feed) and T3 (basal diet with organic Zn as Zinc Proteinate (ZnPro) @ 30 g/ton of feed). The overall body weight gain (BWG), feed consumption (FC), feed conversion ratio (FCR), and European Production Efficiency Factor (EPEF) were recorded for five weeks. Dressing parameters, antioxidant profile, metallothionein (MT) mRNA gene expression, and tibia parameters were evaluated at the end of the experiment. Supplementation of organic Zn as Zinc Mono Glycinate (ZnGly) @ 27.5g/ton and Zn Proteinates @ 30.0 g/ton of feed was beneficial in improving (p<0.05) FCR without affecting BWG and dressing parameters in broilers. However, EPEF and FC were significantly lower in T3 than T1 and T2. The malondialdehyde (MDA) lipid peroxidation and glutathione peroxidase levels in blood were significantly (p≤0.05) lower and higher, respectively, in T2 than T1, while T2 and T3, as well as T3 and T1, were comparable. Non-significant differences were observed for blood lipid peroxidation/MDA level and plasma total antioxidant capacity between T1, T2, and T3. Percent tibia ash and tibia bone weight were comparable between T1, T2, and T3. However, the tibia Zn content was significantly improved in T2 and T3 than T1. The significantly higher MT mRNA gene expression in liver and duodenal tissue was recorded in T2 and T3 than T1, indicating higher bioavailability of ZnGly and ZnPro than ZnS.