Evaluation of Bentonite as a Feed Additive to Improve Egg Quality in 74-week Old Laying Hens

Bentonite is commonly used as a feed additive in poultry rations to increase growth, egg production, or nutrient digestibility. Thus, the aim of this study was to investigate the effects of bentonite supplementation on egg quality in 74-week old laying hens. A total of 300 laying hens were randomly divided into two groups (150 hens each either on a basal diets (control) or 0.5% bentonite diet) and were housed in 10 wire-caged pens for 4 weeks. The egg samples were analyzed for egg weight, shell thickness, shell color, yolk color, yolk index, albumen height, and Haugh unit. During the experimental period, there were no significant differences between the control and the bentonite treatment (P>0.05) in egg weight, shell thickness, shell color, yolk color, and yolk index. However, an increasing tendency in shell thickness and shell color was observed as the hens aged (P<0.05) at weeks 1 and 4 and shell color at weeks 3 and 4. For albumen height and Haugh unit, the differences between the control and the bentonite treatment were not statistically significant (P>0.05) except for a significant effect (P<0.05) in Haugh unit at weeks 3 and 4. The supplementation of 0.5% bentonite to the diets of 74-week old laying hens had some positive effects on shell thickness, shell color, and Haugh unit.