Sodium levels in the diets of semi-heavy laying hens reared in a hot climate after peak lay

Abstract

The objective of this study was to estimate the sodium (Na) requirements of semi-heavy laying hens reared in a hot climate after peak lay. A total of 120 Hisex Brown hens, 48 weeks of age, were used. The birds were allocated in a completely randomized design consisting of five treatments, six replicates and four animals per experimental unit. The experimental diets were formulated with corn and soybean meal and the treatments consisted of five levels of sodium (0.12, 0.17, 0.22, 0.27 and 0.32%) derived from common salt. The following parameters were evaluated: feed intake (g), egg production (%), egg weight (g), egg mass (g), feed conversion (kg) per kilogram of eggs and per dozen eggs, specific gravity (g/cm3), shell thickness (mm), egg components including egg yolk (g and %), albumin (g and %) and shell (g and %), viability (%), and variation in body weight (g) of the birds. There was no effect (P>0.05) of sodium levels on egg yolk weight (g) or albumin percentage. A decreasing linear effect (P<0.01) was observed for feed intake, which decreased with increasing sodium level in the diet. A quadratic effect (P<0.05) was found for egg production, egg weight, feed conversion per kilogram of eggs and dozen eggs, albumin and shell weight, specific gravity, shell thickness, and percentage of shell and egg yolk. A sodium level higher than 0.27% negatively influenced egg components and zootechnical performance of the birds. The inclusion of 0.20% sodium in the diet after peak lay is recommended for semi-heavy laying hens reared in a hot climate to increase egg quality and productive performance.

Keywords

• gallus gallus domesticus
• poedeiras comerciais
• produção de ovos
• sal comum.