Estimation of gas production and post-ruminal crude protein from native or ensiled Pisum sativum and Vicia faba grains

Figures & data

Table 1. Nutrient composition of the basal diet components.

Analytes	Haylage	Concentrate
Dry matter (DM), g/kg	807	897
Crude ash	60	80
Crude protein	54	177
Acid ether extract	10	24
Crude fibre	313	88
Neutral detergent fibre (aNDFom)^a^,^b	630	234
Acid detergent fibre (ADFom)^b	333	106
Acid detergent lignin	40	27

Note: Analytes are given in g/kg DM unless otherwise stated.

^aAssayed with a heat stable amylase.

^bExpressed exclusive of residual ash.

Table 2. Fermentation characteristics of the model silages.

Analytes	Field peas	Field beans
After ensiling
Dry matter (DM) reduction, %	1.1	2.9
pH	6.5	6.4
Lactic acid	3.5	11.7
Acetic acid	1.2	4.2
Butyric acid	n.d.	n.d.
Ethanol	6.1	11.2
After 7 days of aerobic storage
pH	6.4	6.2
Aerobic stability^a	≥7	≥7

Note: Analytes are given in g/kg DM unless otherwise stated. n.d.: not detectable.

^aGiven in days until the temperature difference between material and environment exceeds 3°C.

Table 3. Nutrient composition of the test substrates.

Analytes	Native peas	Ensiled peas	Native field beans	Ensiled field beans
Dry matter (DM), g/kg	887	728	908	703
Crude ash	32	36	38	41
Crude protein (CP)	180	205	263	265
True protein	166	175	225	220
Soluble protein, % of CP	78	71	65	67
Acid ether extract	15	18	15	18
Starch	511	486	398	441
Crude fibre	60	55	93	101
Neutral detergent fibre (aNDFom)^a^,^b	134	129	147	173
Acid detergent fibre (ADFom)^b	78	82	126	153
Acid detergent lignin	9	2	10	5
Metabolizable energy, MJ/ kg DM	13.6	13.5	12.8	12.7

Note: Analytes are given in g/kg DM unless otherwise stated.

^aAssayed with a heat stable amylase.

^bExpressed exclusive of residual ash.

Figure 1. Relationship between the 24 h-gas production (mL/200 mg dry matter) from maize starch (Δ), cellulose (○), as well as native peas (♦), ensiled peas (▴), native field beans (▪), and ensiled field beans (●), measured with the modified Hohenheim Gas Test (modified HGT) and the ANKOM RF Gas Production System (AGPS); regression equation: gas production (modified HGT) = 22.44416 + 0.998141 × gas production (AGPS); R² = 0.57.

Figure 2. Cumulative gas production from maize starch (Δ), cellulose (○), as well as native peas (♦), ensiled peas (▴), native field beans (▪), and ensiled field beans (●) during 24 h of incubation, measured with the ANKOM RF Gas Production System; DM, dry matter.

Table 4. Least squares means of 24 h-gas production (mL/200 mg dry matter) ± standard error from different test substrates measured with the modified Hohenheim Gas Test (modified HGT) and the ANKOM RF Gas Production System (AGPS).

Substrate	Modified HGT	AGPS
Native peas	69 ± 1.4^aB	46 ± 1.4^bA
Ensiled peas	66 ± 1.6^aA	45 ± 1.6^bA
Native field beans	55 ± 1.5^aC	35 ± 1.5^bB
Ensiled field beans	53 ± 1.3^aB	34 ± 1.3^bB
Maize starch	79 ± 1.5^aA	50 ± 1.5^bA
Vitacel® R200 cellulose	68 ± 3.4^aB	38 ± 3.1^bB

^a,bDifferent lower-case superscripts indicate differences between measurements by the two models (P < 0.001).

^A,B,CDifferent upper-case superscripts within a column indicate differences among untreated substrates (P < 0.05).

^A,B Different upper-case italic superscripts within a column indicate differences between ensiled peas and field beans (P < 0.001). Ensiling itself had no effect on gas production from peas or field beans.

Figure 3. Concentrations of post-ruminal crude protein (PRCP) in native peas (♦), ensiled peas (▴), native field beans (▪), and ensiled field beans (●) at assumed ruminal passage rates (Kp) of 0.02 (Kp2), 0.04 (Kp4), 0.06 (Kp6), 0.08 (Kp8), and 0.12/h (Kp12), determined with (A) the modified Hohenheim Gas Test, or (B) the ANKOM RF Gas Production System; standard errors ranged between 3.16 and 14.2 g/kg DM; ^abcde different superscripts mark differences among Kp for same species and treatment (P < 0.05) (in A, differences only belong to field bean treatments ▪ and ●); † PRCP differed between native and ensiled field beans (P < 0.05), ‡ PRCP differed between native peas and field beans (at Kp8 and Kp12 in A, and at Kp4 to Kp12 in B), and between ensiled peas and field beans (at Kp6 to Kp12 in B) (P < 0.05), DM = dry matter.

Table 5. Least squares means of post-ruminal crude protein at 8 or 24 h of incubation (g/kg dry matter) ± standard error from different test substrates determined with the modified Hohenheim Gas Test (modified HGT) and the ANKOM RF Gas Production System (AGPS).

Substrate	Duration	Modified HGT	AGPS
Native peas	8 h	187 ± 6.20^aAYA	163 ± 5.54^bAYA
	24 h	177 ± 6.20^aAXA	133 ± 5.54^bAYB
Ensiled peas	8 h	188 ± 7.16^aAXA	170 ± 5.54^aAYA
	24 h	180 ± 7.16^aAXA	136 ± 5.54^bAXB
Native field beans	8 h	206 ± 6.20^bAXA	225 ± 5.06^aAXA
	24 h	184 ± 6.20^aAXB	163 ± 5.06^bAXB
Ensiled field beans	8 h	191 ± 6.20^bAXA	230 ± 5.06^aAXA
	24 h	172 ± 6.20^aAXB	146 ± 5.54^bBXB

^a,bDifferent lower-case superscripts indicate differences between measurements by the two systems (P < 0.05).

^A,BDifferent upper-case superscripts within a column indicate differences among treatments (native or ensiled) of the same substrate and with the same duration of incubation (P < 0.05).

^X,YDifferent upper-case superscripts within a column indicate differences among substrates with the same treatment and with the same duration of incubation (P < 0.05).

^A,B Different upper-case italic superscripts within a column indicate differences between the durations of incubations (8 or 24 h) in the substrates with same treatment (P < 0.05).