Effects of different rearing systems on growth performance, nutrients digestibility, digestive organ weight, carcass traits, and energy utilization in male broiler chickens

A total of 600 male broiler chickens were randomly allocated to 1 of the following 3 rearing systems, multilayer cage rearing system (CRS), litter rearing system (LRS), and plastic flat net rearing system (NRS), to investigate the effects of different rearing systems on growth performance, nutrients digestibility, digestive organ weight, carcass traits, and energy utilization in male broiler chickens with 10 replicate cages or pens and 20 chickens per cage or pen. Growth performance was determined on d 0, 21, and 42, and all other response criteria were determined on d 21or 42. Weight gain and feed conversion ratios were not affected by 3 different rearing systems. However, feed intake in LRS treatment was lower (P<0.05) than the other 2 treatments during d 0 to 21.The apparent ileal digestibility (AID) of dry matter and N were not affected by different rearing systems, while CRS treatment had lower AID for energy than other 2 treatments at d 42 (P<0.05). Broiler chickens on LRS treatment had a heavier gizzard than other 2 treatments at both d 21 and 42 (P<0.05). Carcass yield, breast meat yield, breast weight, and thigh weight were unaffected by different rearing systems at both d 21 and 42. At d 42, thigh yield in broiler chickens on CRS treatment was greater than those on NRS treatment (P<0.05). Broiler chickens on CRS treatment had a lower abdominal fat than those on other 2 treatments at d 21 (P<0.05). However, it was found that the lowest and the greatest abdominal fat were observed with CRS and LRS treatments, respectively, at d 42 (P<0.05). Broiler chickens reared in LRS had lower apparent ileal digestible energy intake than those in CRS and on NRS during d 0 to 21 (P<0.05). Apparent ileal digestible energy (AIDE), net energy for production, energy retained as fat (REf) and protein (REp), efficiency (k) of AIDE use for total retention (kRE), lipid retention (kREf), and protein retention (kREp) did not differ among the treatment groups at any point during the experimental period. In conclusion, the results of the current study indicated that growth performance, energy retention (REf and REp), and efficiencies of energy utilization (kRE, kREf, and kREp) were >unaffected by different rearing systems. In addition, broiler chickens reared in CRS had lower AIDE than those reared in other 2 rearing systems during the later phase.