Performance and egg quality of commercial laying hens fed with various levels of protected sodium butyrate

Two experiments were conducted to evaluate the effect of including protected sodium butyrate (PSB) in the diets of laying hens of advanced age on productive performance and egg quality. In experiment 1, a total of 320 Dekalb White 61-week-old laying hens were distributed in a randomized block design to four treatments (0, 105, 210, and 300 g/ton of PSB) with eight replicates of 10 birds. The experiment was conducted over 112 days, divided into four periods of 28 days each. Productive performance and egg quality were evaluated. In experiment 2, a total of 58 000 Dekalb White 70-week-old laying hens were assigned to diets containing either 0 or 105 g/ton of PSB with two replicates of 14 500 birds. The experiment was conducted on a commercial poultry farm. Egg production and the percentages of broken eggs and dirty eggs were evaluated. The PSB levels did not influence the productive performance of laying hens. A quadratic effect was observed for eggshell thickness, percentage of eggshell and eggshell strength, reaching maxima at 193, 136 and 198 g/ton of PSB, respectively. A quadratic effect on yolk index reached a minimum at 181 g/ton of PSB. The percentages of dirty eggs and broken eggs were lower in laying hens fed 105 g/ton of PSB. In conclusion, the addition of PSB to the diets of old laying hens improved the eggshell quality and decreased the percentage of broken and dirty eggs Keywords: egg quality, laying hens, organic acids, performance, protected sodium butyrate