Table 3.

True protein digestibility of defatted walnuts^a.

Group	Subject	Feed intake, g DM	Nitrogen intake, mg	mg Nitrogen intake/g DM intake	Calculated Fecal Nitrogen, mg	Metabolic Nitrogen, mg Fecal N/g DM intake	Corrected Metabolic Nitrogen, mg Fecal N/g DM intake
Nitrogen-free	1	21.5	13.1	0.6	13.2	0.61
Nitrogen-free	2	18.8	11.4	0.6	10.1	0.54
Nitrogen-free	3	21.5	13.1	0.6	18.8	0.88
Nitrogen-free	4	20.6	12.5	0.6	12.7	0.62
Test	5	41.2	903.9	21.9	145.8	3.53	2.87
Test	6	43.0	943.2	21.9	192.7	4.48	3.82
Test	7	39.4	864.6	21.9	137.3	3.48	2.82
Test	8	43.0	943.2	21.9	138.8	3.23	2.57
Nitrogen-free (Mean ± SD)		20.6 ± 1.3	12.5 ± 0.8	0.6 ± 0.0	13.7 ± 3.7	0.66 ± 0.15
Test (Mean ± SD)		41.7 ± 1.7	913.7 ± 37.6	21.9 ± 0.0	153.7 ± 26.3	3.68 ± 0.55	3.02 ± 0.55
True protein digestibility estimate
I		21.9 ± 0.0
F		3.68 ± 0.55
Fk		0.66 ± 0.15
TD		86.22% ± 1.83%

^aTrue protein digestibility was estimated using the equation $TD=\frac{I-(F-Fk)}{I}$, where I is equal to nitrogen intake, F is equal to fecal nitrogen of the test diet, and Fk is equal to fecal nitrogen of the nitrogen-free diet. Estimates were corrected for dry matter intake. Bolded numbers indicate values used in the calculation of true protein digestibility.

N, nitrogen; DM, dry matter.