Effect of utilization of maize silage in moult inducing diets on performance, immune response and bone quality in laying hens.

The aim of the study was to evaluate the utilization of maize silage (MS) in moult induction and its effects on immune response and bone quality in laying hens. Laying hens were subjected to 1 of 6 treatments: full-fed (control; FF); total feed withdrawal (positive control for moult induction; FW); 100 MS (M100); 90 MS + 10 layer ration (LR) (M90); 80 MS + 20 LR (M80); and 70 MS + 30 LR (M70). After 9 days body weight loss occurred in all moulting treatments. The examined treatments caused cessation of egg production on day 4 (M90), 5 (FW, M100) and 7 (M70, M80). On day 6 the heterophil : lymphocyte (H:L) ratio did not differ between all MS treatments and FF; however FW caused its increasing only in comparison to FF, M80 and M70. On day 9 H:L ratio for FF did not differ only from M70 and M90. Antibody production against sheep red blood cell was unaffected by all moulting treatments. The femur dry weight for FF did not differ from M70, M80, M100; however there was observed no difference between FW and M70, M90, M100. The treatments caused decrease of femur ash content in comparison to FF group (except M70) with the lowest value in FW. In conclusion, obtained data indicate that the use of MS mixed with LR results in moult induction. Likewise, it is suggested to use 70 MS addition because of reduced moulting stress in birds and smaller losses of bone mineralization.