The test diet used to construct BCAA levels for response surface treatments is presented in Table 1. Digestible nutrients are presented in Table 1. Analyzed amino acid treatment additions agree with calculated treatment levels (Table 2). Predicted means of live performance and dressed yields are presented in Table 3 and their respective P values are presented in Table 4. Mortality averaged 0.98% for female broilers and 1.31% for male broilers, and treatment differences did not occur.
Table 2
Branched-chain amino acid (BCAA) calculated treatments and subsequent analyzed CP and amino acids
| BCAA/Lys dietary treatments | | | Dietary analysis | |
Val | Ile | Leu | CP | Lys | Val | Ile | Leu |
65 | 58 | 130 | 18.64 | 1.20 | 0.86 | 0.72 | 1.59 |
65 | 66 | 110 | 18.80 | 1.20 | 0.82 | 0.79 | 1.37 |
65 | 66 | 150 | 19.28 | 1.22 | 0.83 | 0.79 | 1.78 |
65 | 74 | 130 | 18.31 | 1.13 | 0.79 | 0.83 | 1.56 |
75 | 58 | 110 | 18.63 | 1.17 | 0.91 | 0.70 | 1.38 |
75 | 58 | 150 | 18.20 | 1.17 | 0.92 | 0.70 | 1.77 |
75 | 66 | 130 | 19.13 | 1.20 | 0.92 | 0.78 | 1.58 |
75 | 74 | 110 | 19.02 | 1.21 | 0.94 | 0.87 | 1.40 |
75 | 74 | 150 | 19.46 | 1.22 | 0.95 | 0.89 | 1.81 |
85 | 58 | 130 | 18.13 | 1.20 | 1.03 | 0.70 | 1.59 |
85 | 66 | 110 | 18.45 | 1.19 | 1.04 | 0.79 | 1.41 |
85 | 66 | 150 | 18.88 | 1.21 | 1.05 | 0.80 | 1.80 |
85 | 74 | 130 | 18.51 | 1.22 | 1.04 | 0.86 | 1.59 |
Table 3
Predicted means for live performance and dressed yields as affected by variation of diet branched-chain amino acids1 fed from 22 to 35 d to female Indian River broilers2
| | | | Live performance3 | | | Dressed yields4 | |
Val | Ile | Leu | BW gain | Feed:gain | Mortality | Carcass | Breast | Fat |
| | | kg/bird | kg:kg | % | % | % | % |
| | | Female broilers |
65 | 58 | 130 | 1.122 | 1.92 | 0.17 | 69.71 | 25.93 | 2.11 |
65 | 66 | 110 | 1.107 | 1.95 | 1.18 | 69.16 | 26.28 | 1.94 |
65 | 66 | 150 | 1.061 | 1.96 | 0.97 | 69.74 | 26.46 | 2.00 |
65 | 74 | 130 | 1.124 | 1.94 | 1.56 | 70.09 | 26.96 | 1.97 |
75 | 58 | 110 | 1.163 | 1.88 | 0.31 | 69.97 | 26.15 | 1.92 |
75 | 58 | 150 | 1.072 | 2.00 | 1.08 | 69.35 | 25.88 | 2.00 |
75 | 66 | 130 | 1.088 | 1.94 | 0.83 | 70.64 | 26.25 | 1.85 |
75 | 74 | 110 | 1.107 | 1.96 | 1.98 | 69.92 | 26.66 | 1.93 |
75 | 74 | 150 | 1.133 | 1.92 | 1.08 | 69.99 | 26.18 | 1.88 |
85 | 58 | 130 | 1.121 | 1.93 | 0.66 | 69.79 | 26.46 | 1.90 |
85 | 66 | 110 | 1.094 | 1.91 | 0.97 | 70.01 | 26.74 | 1.86 |
85 | 66 | 150 | 1.074 | 1.97 | 1.04 | 68.89 | 25.82 | 1.83 |
85 | 74 | 130 | 1.124 | 1.91 | 0.94 | 70.00 | 26.24 | 1.94 |
SE5 center point | 0.0289 | 0.026 | 0.509 | 0.439 | 0.321 | 0.099 |
SE edge points | 0.0251 | 0.023 | 0.441 | 0.381 | 0.278 | 0.085 |
| | | Male broilers |
65 | 58 | 130 | 1.382 | 1.89 | 1.36 | 69.83 | 25.68 | 1.73 |
65 | 66 | 110 | 1.394 | 1.85 | 0.92 | 69.80 | 26.23 | 1.74 |
65 | 66 | 150 | 1.337 | 1.89 | 1.14 | 70.01 | 26.17 | 1.67 |
65 | 74 | 130 | 1.379 | 1.81 | -0.48 | 70.16 | 26.48 | 1.61 |
75 | 58 | 110 | 1.419 | 1.86 | 1.84 | 70.26 | 25.78 | 1.74 |
75 | 58 | 150 | 1.349 | 1.98 | 2.79 | 69.41 | 25.47 | 1.69 |
75 | 66 | 130 | 1.342 | 1.92 | 1.47 | 69.87 | 25.71 | 1.86 |
75 | 74 | 110 | 1.381 | 1.86 | 1.03 | 69.77 | 26.23 | 1.53 |
75 | 74 | 150 | 1.403 | 1.86 | 1.69 | 70.27 | 26.31 | 1.63 |
85 | 58 | 130 | 1.388 | 1.89 | 1.07 | 69.95 | 25.35 | 1.72 |
85 | 66 | 110 | 1.378 | 1.84 | 0.92 | 70.16 | 25.80 | 1.63 |
85 | 66 | 150 | 1.386 | 1.91 | 2.32 | 69.59 | 25.62 | 1.74 |
85 | 74 | 130 | 1.407 | 1.84 | 0.99 | 69.98 | 25.83 | 1.57 |
SE5 center point | 0.0402 | 0.034 | 0.598 | 0.375 | 0.293 | 0.081 |
SE edge points | 0.0348 | 0.029 | 0.517 | 0.325 | 0.254 | 0.071 |
1Branched-chain amino acids represent: dietary digestible levels of valine, isoleucine, and leucine in ratio to dietary digestible lysine. |
2Coding coefficients for branched-chain amino acids of -, 0, and + were used and arithmetic means were used to estimate predicted means for linear, quadratic, and crossproduct regression analyses using the RSREG procedure of SAS. Each value represents the predicted mean of ten replicates (36 birds per replicate). The average body weight for female and male broilers was 1.107 and 1.380, respectively, for both the arithmetic and predicted means. |
3Live performance represents: body weight (BW) gain in kg per bird from the 15 to 35 d period; feed:gain represents kg feed intake divided by body weight gain for the 15 to 35 d period without the mass of birds that died; and mortality represents percentage birds that died from the 15 to 35 d period. |
4Dressed yields represents: hot carcass, total breast muscles, and abdominal fat relative to live BW of processed birds. |
5SE represents: standard errors of center point means (valine, isoleucine, and leucine of 75, 66, and 130, respectively) and standard errors of edge point means (additional 12 treatments). |
Table 4
P values for broiler live performance and dressed yields as affected by variation of diet branched-chain amino acids from 22 to 35 d fed to female Indian River broilers
| | | | Live performance2 | | | Dressed yields3 | |
P values1 | | | BW gain | Feed:gain | Mortality | Carcass | Breast | Fat |
| | | kg/bird | kg:kg | % | % | % | % |
| | | Female broilers |
Linear | | | | | | | | |
Val | | | 0.894 | 0.924 | 0.685 | 0.023 | 0.503 | 0.317 |
Ile | | | 0.031 | 0.156 | 0.449 | 0.638 | 0.504 | 0.224 |
Leu | | | 0.386 | 0.786 | 0.958 | 0.029 | 0.358 | 0.706 |
Quadratic | | | | | | | | |
Val x Val | | | 0.996 | 0.888 | 0.918 | 0.061 | 0.550 | 0.400 |
Ile x Ile | | | 0.074 | 0.697 | 0.918 | 0.512 | 0.929 | 0.224 |
Leu x Leu | | | 0.842 | 0.408 | 0.472 | 0.029 | 0.792 | 0.924 |
Cross product | | | | | | | | |
Ile x Val | | | 0.990 | 0.459 | 0.277 | 0.848 | 0.053 | 0.371 |
Leu x Val | | | 0.648 | 0.340 | 0.786 | 0.055 | 0.088 | 0.660 |
Leu x Ile | | | 0.045 | 0.003 | 0.104 | 0.430 | 0.749 | 0.473 |
| | | Male broilers |
Linear | | | | | | | | |
Val | | | 0.392 | 0.268 | 0.541 | 0.753 | 0.897 | 0.314 |
Ile | | | 0.156 | 0.309 | 0.836 | 0.540 | 0.842 | 0.067 |
Leu | | | 0.206 | 0.406 | 0.229 | 0.747 | 0.322 | 0.587 |
Quadratic | | | | | | | | |
Val x Val | | | 0.537 | 0.112 | 0.116 | 0.878 | 0.727 | 0.157 |
Ile x Ile | | | 0.254 | 0.367 | 0.781 | 0.764 | 0.757 | 0.023 |
Leu x Leu | | | 0.559 | 0.742 | 0.229 | 0.959 | 0.359 | 0.119 |
Cross product | | | | | | | | |
Ile x Val | | | 0.789 | 0.617 | 0.142 | 0.681 | 0.584 | 0.812 |
Leu x Val | | | 0.426 | 0.645 | 0.327 | 0.295 | 0.856 | 0.264 |
Leu x Ile | | | 0.256 | 0.113 | 0.806 | 0.073 | 0.505 | 0.352 |
1Linear, quadratic, and crossproduct regression analyses parameters for predicted means were generated using the RSREG procedure of SAS. All parameters have a df of 1. |
2Live performance represents: body weight gain in kg per bird from the 15 to 35 d period; feed:gain represents kg feed intake divided by BW gain for the 15 to 35 d period without the mass of birds that died; and mortality represents percentage birds that died from the 15 to 35 d period. |
3Dressed yields represents: hot carcass, total breast muscles, and abdominal fat relative to live body weight of processed birds. |
For body weight gain, quadratic responses to isoleucine (P = 0.07) were observed in female broilers, but no effects were observed in male broilers. An interaction occurred for body weight gain in female broilers (P = 0.05) where isoleucine improved body weight gain across dietary leucine levels, but the amount of dietary isoleucine needed to improve body weight gain increased with increasing leucine (Fig. 1).
Quadratic responses for feed conversion did not occur in female or male broilers, but an isoleucine by leucine interaction (P > 0.01) occurred in female broilers as shown in Fig. 2. Isoleucine compromised feed conversion when dietary leucine was low, but improved feed conversion when leucine was increased.
Dietary valine and leucine responses in female broilers resulted in quadratic responses for carcass yield. Linear or quadratic responses for carcass yield in male broilers to dietary BCAA did not occur. The interaction (Fig. 3) indicated that as dietary leucine reached 129 and valine reached 75, carcass yield in female broilers was heightened (P = 0.06). The only interaction for male broilers was in carcass yield as shown in Fig. 4. Male carcass yield was improved with either the combination of the lowest levels of dietary leucine and isoleucine, or the highest levels of leucine and isoleucine, with high dietary leucine in the presence of low isoleucine resulting in the poorest carcass yield response (P = 0.07).
Male breast meat yield responses were not affected by the dietary BCAA, but isoleucine by valine (P = 0.05) and leucine by valine (P = 0.09) interactions in female broilers are shown in Fig. 5. Female broilers fed the lowest levels of isoleucine and leucine in the presence of the highest dietary valine has the best breast meat yield responses. However, the opposite response occurred at the lowest level of valine where both isoleucine and leucine were needed to improve breast meat yield in female broilers.
Female dietary BCAA responses for abdominal fat yield did not occur, but male broilers had linear and quadratic responses to dietary isoleucine (P = 0.07 and P = 0.02, respectively). The female isoleucine response indicates reduced fat yields when dietary levels are increase above a ratio of 66 to lysine.