Investigation of ME Level of Molt Diet for Full Fed Induced Molting in Laying Hens

This study investigated the suitable metabolizable energy (ME) level of molt diet for hens that cease producing eggs without being subjected to great stress. During the preliminary period, White Leghorn hens were fed a corn-soybean meal-based layer ration ad libitum. After a 4-wk preliminary period, the hens were randomly divided into 3 treatment groups and 1 control group; the control group was persistently fed the layer ration. The 3 treatment groups were fed the following diets ad libitum for 4wk: (1) 100% molt diet based on corn, wheat bran, and corn gluten feed (ME 2.3Mcal/kg M100:); (2) 85% molt diet with 15% rice hull (ME 1.9Mcal/kg M85:); and (3) 70% molt diet with 30% rice hull (ME 1.6Mcal/kg M70:). During the post-molt period, the hens were returned to the layer ration. During the molting period, the heterophil: lymphocyte (H:L) ratio, ovary and oviduct weights, and ME(n) intake were measured. Egg production, egg weight, egg quality, body weight, and feed intake were measured throughout the experiment. During the molting period, the feed intake, body weight, and ovary and oviduct weights in the molted groups were significantly (P<0.01) lower than those in the control group. In the M70 group, egg production ceased completely within 9 d; and decreased to 4.2% by day 10 and 9 in the M100 and M85 groups, respectively. The H:L ratio was the highest, intermediate, and least in the M70, M100 and M85, and control groups, respectively. At 1, 2 and 4wk, the ME(n) intake in the M70 group was lower than the requirement level. Throughout the post-molt period, the egg production and quality in the molted groups improved compared to that in the control. We assume that ad libitum access to low energy molt diet (ME 1.6Mcal/kg) effectively induces molting and increases post-molt production.