Sodium bentonite as a component in layer diets

1. Two hundred and forty Amber-link pullets were individually caged in a naturally-ventilated laying house and fed one of four isoenergetic, isonitrogenous diets containing 0, 20, 40 or 80 sodium bentonite/kg for 44 weeks. 2. No significant dietary effects were observed between treatments with regard to body weight at 20 or 64 weeks, age at first egg, egg weight, Haugh score or egg shell thickness. 3. Significant positive linear responses were observed with live weight at first egg (P less than 0.01), food consumed/hen d (P less than 0.05) and faecal moisture percentage (P less than 0.01). Significant negative linear (P less than 0.01) responses were observed with bacterial counts in the proximal and distal ends of the intestine. 4. A significant negative quadratic (P less than 0.05) response was noticed with egg production per hen. 5. A significant negative cubic (P less than 0.01) response was found with food conversion ratio (g food/g eggs).