Are the energy matrix values of the different feed additives in broiler chicken diets could be summed?

BMC Veterinary Research

Table 3 The effect of dietary supplementation of NSP-degrading enzymes, LYSO, CreAMINO^® and their combinations on the economic efficiency of the experimental diets:

Parameter	T1	T2	T3	T4	T5	T6	T7	SEM	P-value
Final BW (kg)	2.18^d	2.27^cd	2.36^bc	2.45^ab	2.51^a	2.49^ab	2.27^cd	0.02	0.001
Feed cost (LE)	14.76	14.52	15.06	14.22	15.20	14.57	14.44	0.12	0.290
Total cost (LE)	22.26	22.02	22.56	21.72	22.70	22.07	21.94	0.12	0.290
Total return/bird(LE)	39.38^d	40.95^cd	42.55^bc	44.27^ab	45.34^a	44.84^ab	40.95^cd	0.40	0.001
Net profit (LE)	17.12^c	18.92^bc	19.29^b	22.55^a	22.64^a	22.76^a	19.00^bc	0.40	0.001
E. EF.^*	1.16^c	1.30^bc	1.32^b	1.58^a	1.49^a	1.56^a	1.31^bc	0.03	0.001
Feed cost/kg gain	6.89^a	6.65^a	6.74^a	6.14^bc	6.13^bc	5.95^c	6.47^ab	0.07	0.001
PI (%) ^$	124.39^c	131.28^bc	137.20^b	153.79^a	156.96^a	160.54^a	134.74^bc	2.42	0.001

*Economic efficiency, ^$ Performance index. LE: Egyptian pound.
^a,b,c,d Means within the same row carrying different superscripts are significantly different at (P < 0.05).
T1: Control group "basal diet with no additives (breeder recommendation (BR)). T2: Basal diet minus 100 kcal/kg supplemented with 0.02% NSP-degrading enzymes (NSP). T3: Basal diet minus 50 kcal/kg supplemented with 0.025% emulsifier (LYSOFORTE^®). T4: Basal diet minus 50 kcal/kg supplemented with 0.06% guanidinoacetic acid (CreAMINO^®). T5: Basal diet minus 150 kcal/kg supplemented with a mixture of NSP and LYSOFORTE^® (NSPL), T6: Basal diet minus 100 kcal/kg supplemented with a mixture of NSP and CreAMINO^® (NSPC). T7: Basal diet minus 200 kcal/kg supplemented with a mixture of NSP, LYSO, and CreAMINO^® (NSPLC).