. 2018 Mar 8;2(2):205–215. doi: 10.1093/tas/txy007

Table 1.

Effects of rumen-protected L-Arg supplementation or injected L-Arg-HCl on Arg and selected AA intake, flow, and disappearance in forage-fed steers

	Treatments^a
Item	CON	Arg-INJ	Arg-RP180	Arg-RP360	SEM	P-value
AA intake, g/d
Arg intake, g/d	24.4^b	24.3^b	98.7^c	178.1^d	5.9	<0.001
From rumen-protected Arg	0.0^b	0.0^b	76.1^c	150.6^d	0.6	<0.001
From hay	24.4	24.3	22.5	27.5	5.7	0.34
Orn	0.465	0.475	0.429	0.531	0.085	0.33
Pro	30.1	30.6	27.7	34.1	5.3	0.34
Glu	55.5	55.8	51.1	62.4	10.8	0.35
Lys	25.9	26.1	23.6	28.6	5.0	0.26
His	8.16	8.20	7.54	9.19	1.70	0.34
Met	7.65	7.62	7.06	8.66	1.77	0.34
Ruminal disappearance, g/d
Arginine	4.2^b	6.5^b	68.7^c	135.4^d	3.5	<0.001
Ornithine	−0.828	−0.683	−0.876	−1.303	0.231	0.25
Proline	9.47	9.73	6.86	10.50	3.58	0.46
Glutamate	6.25	7.77	3.53	6.90	6.89	0.69
Lysine	−4.25	−2.88	−5.23	−4.61	3.09	0.46
Histidine	0.162	0.494	−0.056	0.515	1.047	0.76
Methionine	0.386	0.792	0.116	0.648	1.020	0.51
Duodenal flow, g/d
Arg	19.4^b	18.0^b	29.2^c	43.1^d	3.4	<0.001
Orn	1.24	1.18	1.25	1.83	0.26	0.23
Pro	20.5	20.9	20.7	23.6	2.5	0.32
Glu	48.6	48.5	47.0	55.4	5.3	0.33
Lys	29.8	29.2	28.5	33.2	3.2	0.40
His	7.86	7.78	7.46	8.67	0.85	0.46
Met	7.17	6.88	6.85	8.00	0.91	0.40
Ileal flow, g/d
Arg	9.07^b	9.84^b,c	13.58^c	21.06^d	2.13	0.01
Orn	0.709^b	0.797^b	0.793^b	1.121^c	0.094	0.01
Pro	13.3	14.6	15.0	18.1	1.9	0.17
Glu	26.7^b	29.5^b	30.5^b	38.5^c	4.1	0.09
Lys	11.9	13.8	14.5	17.8	2.0	0.15
His	4.58	5.23	5.66	7.09	0.89	0.15
Met	3.14	3.51	3.69	4.74	0.56	0.12
Small intestinal disappearance, g/d
Arginine	9.58^b	8.92^b	14.86^c	21.72^d	1.80	0.003
Ornithine	0.543	0.384	0.468	0.730	0.227	0.66
Proline	6.96	6.44	5.45	5.47	1.97	0.48
Glutamate	21.1	19.4	15.7	16.7	4.0	0.44
Lysine	17.6	15.7	13.7	15.2	2.3	0.29
Histidine	3.01	2.76	1.53	1.51	0.70	0.22
Methionine	3.94	3.42	3.07	3.24	0.60	0.33

^aTreatments included: ad libitum grass hay (CON), CON hay with 27-mg L-Arg-HCl/kg BW injected twice daily (54 mg/kg BW daily; Arg-INJ), CON hay with 90-mg rumen-protected L-Arg/kg BW supplemented twice daily (180 mg/kg BW daily; Arg-RP180), and CON hay with 180-mg rumen-protected L-Arg/kg BW supplemented twice daily (360 mg/kg BW daily; Arg-RP360).

^b,c,dMeans within a row without a common letter superscript differ (P ≤ 0.05).