This experiment was designed to determine interactive effects between dietary sodium bentonite (SB) containing ferric oxide and free gossypol (FG) on internal egg quality during cold storage. In a 3 × 3 factorial arrangement in a CRD with 9 dietary treatments in 4 replicates consisting of 3 levels of SB (0, 1, and 2%) and 3 levels of CSM (0, 10, and 20%) were tested. Nine mash diets were fed to 288 commercial Hy-Line W-36 hens from 51 to 62 wk of age after 1 wk of acclimatization. Each experimental unit consisted of 2 cages with 4 birds per cage. The 4 eggs were randomly chosen in each experimental unit from the eggs laid during the 4 consecutive days at every 28-d period (total 3 periods) and then were stored at 4°C for 1, 2, 3, and 4 wk to enhance yolk discoloration, respectively. After storage, eggs were individually opened, and the degree of yolk discoloration was scored based on egg yolk scoring protocol. After determination of albumen spread, the yolk was separated from the albumen and the pH of yolk and albumen was measured. Data were analyzed using the GLM procedure of SAS 9.1. Tukey’s Studentized Range (HSD) test was used to compare means (P < 0.05).Yolk score significantly (P < 0.01) increased with increasing of CSM and significantly (P < 0.01) diminished with increasing of SB in the diet during cold storage. There was no significant effect of dietary treatments on spread of albumen, but albumen quality gradually decreased during 4 weeks. Generally, pH of yolk and albumen increased after cold storage. There was no significant effect of dietary treatments on pH of yolk or albumen. Egg discoloration in the current research was limited to that associated with gossypol. No eggs were observed to have developed pink albumen. In this study, cloudy white was sometimes observed after cold storage in all treatments. The yolks of eggs laid by hens consuming CSM became rubbery, viscous, and pasty in appearance after cold storage. Under the conditions of this experiment, SB in the diet was useful for reduction of yolk discoloration.

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