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. 2018 Nov 16;97(2):698–713. doi: 10.1093/jas/sky441

Table 9.

Regression equations and coefficients of the influence of digestible lysine requirements of broilers fed different doses of phytase from hatch to 42 d posthatch (Exps. 1 and 2)

Trait !y Regression equation1 R 2 Predicted dgLys requirement !x Predicted phytase dose !v to max !y
% FTU/kg
Experiment 1
Digestible lysine requirements !x and optimum phytase dose !v for broilers from hatch to 21 d posthatch
BW gain, g !y = −2,154 + 62.29!x – 0.3140!x2 + 0.0263!v – 6.3727e-6!v2 0.64 99.3 2,065
Feed intake, g !y = −404.3 + 32.63!x – 0.1647!x2 0.29 98.9 -
FCR, g:g !y = 4.227 + 0.0593!x + 0.0003!x2 – 4.4677e-5!v + 1.1017e-8!v2 0.84 98.9 2,038
Digestible lysine requirements !x and optimum phytase dose !v for broilers from hatch to 42 d posthatch
BW gain, g !y = −2,080 + 93.71!x – 0.4768!x2 + 0.0599!v – 1.3982e-5!v2 0.59 98.2 2,146
Feed intake, g !y = 2,038 + 43.29!x – 0.2219!x2 0.08 97.6 -
FCR, g:g !y = 3.7748 – 0.0431!x + 0.0002!x2 – 3.5667e-5!v + 7.7502e-9!v2 0.69 98.9 2,308
Carcass weight3, g !y = 1,465 + 7.9611!x + 0.3794!v – 2.9318e-5!v2 – 0.0028!xv 0.14 - -
Breast weight3, g !y = 218 + 5.2906!x + 0.1405!v – 0.0014!xv 0.18 - -
Breast, % carcass !y = −29.46 + 1.2472!x – 0.0062!x2 0.17 99.71 -
Experiment 2
Digestible lysine requirements !x and optimum phytase dose !v for broilers from hatch to 21 d posthatch
BW gain, g !y = −614 + 28.06!x – 0.1326!x2 + 0.0417!v – 9.7264e-6!v2 0.35 104.0 2,130
FCR, g:g !y = 2.5967 – 0.0229!x + 0.0001!x2– 6.8104e-5V + 1.7125e-8!v2 0.78 104.0 1,990
AID lysine, % !y = 85.699 + 0.06425!x 0.07 >104.0 -

1Regression equations were determined using linear and quadratic estimates for both phytase and digestible lysine concentration in the diet as well as the interaction. Non-significant effects were removed from the model. - unable to predict based on the model.