Two experiments were conducted to evaluate the prevalence and severity of white striping (WS) and wooden breast (WB) in breast fillets from broilers fed diets with increasing digestible Lysine (dLys) from 12 to 28 d (Exp. 1) and from 28 to 42 d (Exp. 2). Trials were sequentially conducted using one-d-old male, slow-feathering Cobb 500 × Cobb broilers, both with 6 treatments and 8 replicates. Increasing dLys levels were equally spaced from 0.77 to 1.17% in Exp. 1 and from 0.68 to 1.07% in Exp. 2. The lowest dLys diet was not supplemented with L-Lysine (L-Lys) in either one of the studies and all other essential amino acid (AA) met or exceeded current commercial recommendations such that their dietary concentrations did not limit broiler growth. Four birds per pen were randomly selected from each replication and processed at 35 and 42 d in Exp. 1 and Exp. 2, respectively. Deboned breast fillets (Pectoralis major) were submitted to a 3 subject panel evaluation to detect the presence of WS and WB, as well as to provide scores of WS (0-normal, 1-moderate, 2-severe) and WB (0-normal, 1-moderate light, 2-moderate, 3-severe). Increasing the level of dLys had a positive effect on BW, carcass, and breast weight, as well as breast yield. White striping and WB prevalences were 32.3 and 85.9% in Exp. 1 and 87.1 and 89.2% in Exp. 2. Birds fed diets not supplemented with L-Lys had the lowest average WS and WB scores (0.22 and 0.78 in Exp. 1 and 0.61 and 0.68 in Exp. 2). White striping and WB presented linear responses to performance variables in Exp. 1, whereas quadratic responses were observed for all variables in Exp. 2. In conclusion, increasing the level of dLys improved growth performance and carcass traits as well as induced the occurrence and severity of WS and WB lesions.

Sources of Zn, Mn, and Cu (IZMC) as sulfates or as amino acid complexes (OZMC) were used to supplement Cobb 500 breeder hen diets. Experimental treatments consisted of diets supplemented with 1) 100, 100, and 10 mg/kg of Zn, Mn, and Cu, respectively, from IZMC (control); 2) 60, 60, and 3 mg/kg of Zn, Mn, and Cu, respectively, from IZMC plus 40, 40, and 7 mg/kg of Zn, Mn, and Cu, respectively, from OZMC (ISO); and 3) a diet with 100, 100, and 10 mg/kg of Zn, Mn, and Cu, respectively, from IZMC as in control plus 40, 40, and 7 mg/kg of supplemental Zn, Mn, and Cu from OZMC (on top). Ten replications of 20 females and 2 males were used per treatment. Eggs from breeders at 30, 40, 50 and 60 wk of age were incubated, and 5 embryos per replicate were collected at 10 (E10), 14 (E14), and 18 (E18) d of incubation. Midshaft width and calcification were measured for left tibia and femur stained with Alcian Blue and Alizarin Red S. At hatch, the left tibia of 5 chicks per replicate was sampled for histological evaluation of the diaphysis and distal epiphysis. Feeding the ISO treatment compared with the control diet increased the Zn (P < 0.05) but not Mn and Cu content of the yolk and albumen blend. At E14, the ISO and on-top treatments had a trend to increase tibia calcification at the rates of 1.6 and 1%, respectively (P < 0.1). The E18 ISO and on-top treatments had 2% thicker tibia compared with the control, regardless of hen age (P < 0.05). Also, at E18, calcification of tibia and femur was higher from hens fed the on-top treatment (P < 0.05). The chicks from the ISO and on-top groups had increased tibia moment of inertia (P < 0.01) at day of hatch. Broiler breeder hens consuming OZMC associated with IZMC produced embryos and hatching chicks with improvements in selected bone mineralization parameters.

A study was conducted to evaluate effects of supplementation of a monocomponent protease on growth performance and protein utilization in Nicholas turkeys from 1 to 26 d of age fed corn-soy diets with reduced levels of CP and amino acids. Poults were placed into 40 batteries of 15 birds, and allocated to 5 treatments with 8 replicates each. A positive control diet [PC, 27.94% CP, 1.69 digestible Lys (DLys)] and a negative control diet (NC1; 24.21% CP, 1.46% DLys) were formulated. A second NC diet (NC2; 23.20% CP) was formulated with reduced CP and amino acids (AA) with expected improvements provided by a protease (1.014% CP, 0.024% DLys, 0.055% digestible TSAA, and 0.077% digestible Thr). The protease (75,000 PROT/g) was added at 200 mg/kg, at the expense of Celite (indigestible marker and filler) to create the NC1+P and NC2+P. Ileal contents were collected from all birds for apparent CP and AA digestibility determinations on d 26. A factorial arrangement of 2 × 2 + 1 was used (CP level × protease supplementation + PC). Turkeys fed the PC diet were 8.1% and 9.8% heavier (P < 0.05) compared with those fed the NC1 and NC2 diets and adding protease had no effect on BWG. Improvement in FCR (P < 0.05) were observed in birds fed the NC1 and NC2 diets. There was a main effect of protease (P < 0.0535) on FCR ratio, with birds fed diets with protease having better FCR than those without. There were no effects of the treatments on feed intake and carcass yield. Digestibility of CP was increased (P < 0.05) for turkeys fed the NC1+P diets in comparison to those fed the other diets, except the PC diet. Apparent digestibilities of Asp, Cys, Glu, Ile, Lys, Thr, and Val were affected by treatment, with birds fed the PC diet having the lowest digestibilities (P < 0.05). Poults fed protease-containing diets had better (main effect, P < 0.05) CP, Lys, and Cys digestibilities than those fed the diets without protease. Overall, the effects of the protease were limited but significant on FCR and specific AA digestibilities.