. 2016 Jun 9;11(6):e0157001. doi: 10.1371/journal.pone.0157001

Table 2. Growth performance and plasma ammonia concentration¹.

Histidine¹	Control	3.7	5.9	7.9	9.8	12.2
IBW²	280.6 ± 0.84	279.6 ± 1.68	280.5 ± 0.69	279.1 ± 1.02	279.3 ± 0.67	279.4 ± 0.73
FBW²	511.2 ± 19.0	573.1 ± 8.34^a	679.3 ± 26.41^a	685.4 ± 26.3^a	612.4 ± 18.0^a	574.2 ± 6.94^a
PWG²	82.2 ± 7.24	105.0 ± 2.71^a	142.2 ± 9.69^a	145.6 ± 9.09^a	119.2 ± 5.92^a	105.6 ± 2.16^a
SGR²	1.07 ± 0.07	1.28 ± 0.02^a	1.58 ± 0.07^a	1.60 ± 0.05^a	1.40 ± 0.05^a	1.29 ± 0.02^a
FI²	445.1 ± 5.00	498.5 ± 3.06^a	627.5 ± 2.15^a	602.7 ± 2.53^a	548.3 ± 1.53^a	499.7 ± 3.06^a
FE²	51.80 ± 3.87	58.89 ± 1.92^a	63.51 ± 4.44^a	67.41 ± 4.04^a	60.75 ± 3.1^a	59.01 ± 0.93^a
PER²	1.66 ± 0.12	1.89 ± 0.04^a	2.04 ± 0.14^a	2.16 ± 0.13^a	1.95 ± 0.10^a	1.89 ± 0.03^a
PAC³	365.3 ± 10.8	262.3 ± 12.9^a	176.8 ±11.2^a	153.6 ± 7.32^a	249.3 ± 11.1^a	344.2 ± 12.3^a
Regressions
Y_PWG = -1.965x² + 29.602x + 29.111			R² = 0.9094		P < 0.05
Y_SGR = -1.5893x² + 1.8021x + 1.05			R² = 0.9209		P < 0.05
Y_FI = -5.6275x² + 83.82x + 292.91			R² = 0.8800		P < 0.05
Y_FE = -0.004x² + 0.0614x + 0.4159			R² = 0.9189		P < 0.05
Y_PER = -0.0129x² + 0.1995x + 1.3212			R² = 0.9046		P < 0.05
Y_PAC = 7.6694x²–108.79x + 553.63			R² = 0.9692		P < 0.05

Superscript (^a) in the same row indicates a significant (P < 0.05) difference over control values.

¹Upper half of the table shows different parameters of growth performance (see below) of young grass carp fed diets with graded levels of histidine (first row, g/kg). The lower half shows the regression analysis of data in the upper half of the table.

²Values are expressed as the mean ± SD, mean of three replicates with thirty fish per replicate. The mean values within the same row with different superscripts are significantly different (P < 0.05).

³Plasma ammonia concentration (PAC, μmol/L). Values are expressed as the mean ± SD (n = 6), and mean values within the same row with different superscripts are significantly different (P < 0.05).

IBW: initial body weight (g/fish); FBW: final body weight (g/fish); PWG: percentage weight gain (%); SGR: specific growth rate (%/day); FI: feed intake (g/fish); FE: feed efficiency (%); PER: protein efficiency ratio; PAC: plasma ammonia content.

Weight gain (WG) = FBW (g)–IBW (g);

PWG = 100 × WG (g)/IBW (g);

SGR = 100 × [ln FBW (g)-ln IBW (g)]/number of days;

FE = 100 × weight gain (g)/feed intake (g);

PER = wet weight gain (g)/protein intake (g);

Table 2. Growth performance and plasma ammonia concentration1.

Table 2. Growth performance and plasma ammonia concentration¹.