Effect of dietary inclusion of sulphate, hydroxychloride and organic complex sources of manganese on egg quality of aged laying hens

In order to study the effect of manganese sources in the form of sulphate, hydroxychloride and methionine- chelated manganese organic complex on egg quality of aged laying hens, an experiment was conducted using 384 Hy-line W-36 laying hens at 65 week of age for 8 weeks in completely randomized design with 6 treatments, 4 replications and 16 hens in each replication. The experimental treatments included control (with no Mn supplementation), control plus 50, 70 and 90 mg of Mn as hydroxychloride per kg of diet, control plus 70 mg of manganese as manganese-methionine organic complex per kg of diet and 70 mg of manganese as manganese sulphate per kg of diet. The results showed that the different manganese sources had no significant effect on body weight, feed intake, egg production rate, yolk index, specific gravity and Haugh unit of egg. All treatments had better feed conversion ratio in weeks 6, 8 and in the entire experimental period when compared to control group (P<0.05). All treatments increased egg weight at 8th week and entire experimental period and eggshell thickness, eggshell percentage and eggshell breaking strength during different weeks of experiment when compared to control group (P<0.05). The increase in eggshell strength with 90 mg/kg of manganese hydroxychloride in comparison to 70 mg/kg of manganese sulphate was significant (P<0.05), however no significant difference was observed between 50 mg/kg manganese hydroxychloride and 70 mg/kg manganese-methionine organic complex. The use of manganese organic source or manganese hydroxychloride increased blood and tibia manganese concentrations (P<0.05) in comparison to control group. Generally, the results showed that 50 mg/kg of manganese hydroxychloride can be replaced for 70 mg/kg of manganese-methionine organic complex or manganese sulphate in the diet of aged laying hens.