Effects of Increasing Supplementation of Magnesium in Diets on Productive Performance and Eggshell Quality of Aged Laying Hens

Abstract

Magnesium (Mg) concentrations in diets have been associated with performance and eggshell quality of laying hens, but the results have been inconclusive. In this experiment, the effects of increasing concentrations of dietary Mg on productive performance and eggshell quality of aged laying hens were evaluated. A total of 640 Hy-Line Brown laying hens of 72 weeks of age were randomly allotted to one of four dietary treatments with four replicates per treatment. A commercial-type basal diet containing 1.6 g/kg Mg was prepared, and three additional diets were prepared to contain 2.3, 2.6, or 3.0 g/kg Mg in diets by adding 1.0, 1.5, or 2.0 g of MgO to the basal diet. The diets were fed to hens ad libitum for 5 weeks. Results indicated that Mg concentrations in eggshells were increased (linear, P < 0.01) with increasing concentrations of Mg in diets. Increasing concentrations of Mg in diets decreased (linear and quadratic, P < 0.01) broken and shell-less egg production, but improved (linear, P < 0.05) eggshell strength. Feed intake was decreased (linear, P < 0.05) with the concentrations of Mg in diets, but hen-day egg production, egg weight, feed conversion ratio, and Haugh unit were not affected by increasing concentrations of Mg in diets. Hunter L* and a* values of eggshell were decreased (linear, P < 0.05) as the concentrations of Mg in diets increased. In conclusion, feeding aged laying hens with diets containing increasing concentrations of Mg up to 3.0 g/kg improves eggshell strength, but has no detrimental effects on laying performance.

Effect of dietary magnesium, calcium, phosphorus, and limestone grain size on productive performance and eggshell quality of hens

“…Therefore, our results are in agreement with data from Atteh and Leeson (1983b) regarding Mg and in partial agreement regarding Ca since a wide Ca : NPP ratio and FCL may influence resorption and metabolism of Ca and consequently also Ca deposition in the eggshell. Both high eggshell strength and eggshell thickness due to an increased dietary Mg concentration of 4 g/kg in the experiment with a narrow Ca : NPP ratio are consistent with data from Kim et al (2013). These authors did not observe effects of the dietary Mg concentration up to 3 g/kg on the laying intensity, egg mass, and feed conversion.…”

“…The difference between their results and ours concerning the laying intensity could be related to the Ca : NPP ratio. When the Ca : NPP ratio was narrow, such as in Experiment 1 and in the study by Kim et al (2013), the dietary Mg did not influence the laying intensity, but it increased the eggshell strength. A wide Ca : NPP ratio of 19.5 : 1 and 24 : 1 without Mg supplementation significantly reduced laying intensity in the experiment of Englmaierova et al (2014).…”

“…Magnesium at higher dosing up to 4 g/kg together with CL and at narrow Ca : NPP ratio significantly increased the shell percentage, shell thickness, and shell strength. Previous studies showed that Mg supplementation above 5 g/kg, at 4.7 g/kg, or at 3 g/kg increased the eggshell quality in laying hens (Mehring and Johnson 1965;West et al 1980;Kim et al 2013). In Experiment 1, the Mg supplementation increased Mg concentration in the eggshell and decreased Ca concentration.…”

“…However, the quality of eggshells, especially in aged hens, is low. Most research has been focused on the concentration of Ca in diets because Ca is the major mineral in the eggshell, and its concentration directly affects eggshell quality (Scott et al 1970;Kim et al 2013). The National Research Council (1994) estimated the requirement for Ca, non-phytate phosphorus (NPP), and Mg at 110 g of feed per brown-egg layer daily as 3.6 g, 0.275 g, and 0.055 g, respectively.…”

“…Dietary Mg concentration has been associated with laying performance and eggshell quality (Stafford and Edwards 1973;Ding and Shen 1992;Venglovska et al 2014). Previous experiments indicated that the eggshell strength improved in laying hens when the Mg concentration in their diet was increased above the Mg nutrition requirement (Atteh and Leeson 1983a, b;Hess and Britton 1997;Kim et al 2013).…”