Effect of dietary supplementation of organic minerals on laying performance of hens

Abstract

This study evaluated the effects of different dietary levels and sources of zinc (Zn) and manganese (Mn) on egg production and characteristics in laying hens. A total of 144 layers aged 22 weeks were fed a basal diet as per BIS (1992) specifications for 16 weeks, and were randomly allocated to 6 groups with 24 layers each. First group was kept as negative control (T1) containing mineral mixture without zinc and manganese and T2 (positive control containing mineral mixture with inorganic salts of zinc and manganese) while experimental groups T3, T4, T5 and T6 were supplemented with organic zinc and organic manganese @ 50 and 100% in substitution of inorganic sources. Each group had 4 replicates of 6 hens. Results showed that egg weight and egg mass production during 22-32 weeks of age in different treatments was found similar (P>0.05) and not influenced by any supplementation level of organic minerals. Shell thickness was greater in the organic Zn-added groups (P<0.05), and its relationship with the supplemental level of Zn showed linear effect. Laying hens that received 100% organic minerals (T6) resulted into significantly (P<0.05) higher egg shell weight (5.21) with respect to negative control group (4.74) during 22-24 weeks of age. Egg shell thickness (mm) in all groups differed widely, ranging from 0.30 for T1 to 0.39 for T6 during 22-24 weeks of age. Results obtained in last two weeks of experiment (36-38) showed significantly (P<0.05) increased egg shell thickness in all organic minerals fed groups (0.40, 0.40, 0.40 and 0.41 respectively) in comparison to negative control (0.33). while albumin index of all the birds reached the maximum value of 11.21 at the end of 30 th week and albumin index of the control groups and birds treated with organic minerals was similar (not differed significantly (P<0.05) during the whole experimental trial.