Abstract:
The objective of this study was to assess the effect of reducing dietary digestible lysine (dLys) or metabolizable energy (ME) and amino acid (AA) density during grower or grower and finisher growth phases on incidence and severity of white striping (WS) and footpad dermatitis (FPD) in broiler chickens. A total of 390 one-d-old Ross 308 male broilers were randomly distributed into 5 groups (6 replicate per group; 13 chicks per pen). Control group was fed diets according to the nutrient requirements for starter, grower, finisher, and withdrawal phases. Remaining groups received diets 15% low in dLys or 5% ME and AA density during grower (GRO low Lys and GRO low ME AA groups) or grower and finisher phases (GROFIN low Lys and GROFIN low ME AA groups). At 0-49 d, GROFIN low Lys group had lower body weight (BW) gain in comparison with other dietary treatments except for GRO low Lys (P = 0.010). Breast yield was lowest in GROFIN low Lys group, whereas broilers fed GRO low Lys diets had lower breast yield than those in control and GROFIN low ME AA groups (P < 0.001). Crude protein was lower in broiler chickens fed diets with low ME and AA density than those fed GRO low Lys diets (P = 0.045). Crude fat content of breast meat decreased in broiler chickens fed diets low in dLys content (P = 0.006). Birds in GRO low Lys and GROFIN low Lys groups had lower incidence and severity of WS in comparison with other dietary treatments (P < 0.001). It is concluded that reducing the dietary dLys levels during grower phase reduces the development of WS in broiler chickens by lowering the BW, FI, fat content of breast meat, and fat deposition.
