Ruminal and post-ruminal phytate degradation of diets containing rapeseed meal or soybean meal

Figures & data

Table 1. Analysed composition of single feeds and diets containing rapeseed meal (Diet RSM) or soybean meal (Diet SBM) [g/kg DM^#].

	Rapeseed meal	Soybean meal	Maize silage	Hay
Crude protein	371	526	76	54
Crude ash	88	84	30	59
NDFom^†	325	176	444	696
ADFom^§	264	73	246	462
P	11.6	7.1	2.0	2.0
InsP6	21.6	14.2	n.d^.◊	n.d.
InsP5^¶	3.9	2.6	n.d.	n.d.
InsP4^‡	0.10	n.d.	n.d.	n.d.
Myo-inositol	0.30	0.65	1.88	0.44
	Diet RSM		Diet SBM
InsP6	17.7		11.6
InsP5	3.2		2.1
Myo-inositol	0.57		0.86
P	3.3		2.0

Notes: ^#DM, dry matter; ^†NDFom, neutral detergent fibre expressed exclusive of residual ash; ^§ADFom, acid detergent fibre expressed exclusive of residual ash; ^¶sum of InsP₅ isomers; ^‡sum of InsP₄ isomers; ^◊n.d., not detectable.

Table 2. Estimated ruminal degradation parameters and effective degradability of phytate (InsP₆) and crude protein (CP) from in situ incubation of rapeseed meal (RSM) and soybean meal (SBM).

	RSM	SBM	SEM^#	p-Value
CP degradation
a^† [%]	13	10	-	-
b^§ [%]	82	90	-	-
c^¶ [%/h]	7.9	8.4	0.40	0.349
CPED2^‡ [%]	78	83	0.8	0.006
CPED5 [%]	63	66	0.9	0.038
InsP6 degradation
Lag^◊ [h]	3.6	1.0	0.30	0.005
a [%]	1.9	32	-	-
b [%]	98	68	-	-
c [%/h]	16	23	1.4	0.007
InsP6ED2^♦ [%]	83	93	0.5	0.003
InsP6ED5 [%]	64	85	1.1	0.005

Notes: Data are presented as treatment means; n = 3 animals; ^#SEM, standard error of the mean; ^†a, rapidly degradable fraction; ^§b, potentially degradable fraction; ^¶c, degradation rate; ^‡CPED, effective degradability of CP at rumen passage rates of 2 (CPED₂) and 5 (CPED₅) %/h; ^◊Lag, lag time; ^♦InsP₆ED, effective degradability of InsP₆ at rumen passage rates of 2 (InsP₆ED₂) and 5 (InsP₆ED₅) %/h.

Table 3. Concentrations of inositol phosphate (InsP) isomers in digestive tract contents of wethers fed diets containing rapeseed meal (Diet RSM) or soybean meal (Diet SBM) [g/kg DM^#].

	Diet RSM	Diet SBM	SEM^†	p-Value
InsP6
Rumen pool
Fluid phase	<LOQ^‡	<LOQ	-	-
Small particulate phase	1.53	0.59	0.226	0.026
Large particulate phase	2.21	0.83	0.292	0.015
Omasum + abomasum^§	1.52	0.47	0.206	0.011
Jejunum	0.67	0.23	0.177	0.131
Colon	1.54	0.43	0.236	0.016
Rectum	1.57	0.43	0.256	0.020
InsP5^¶
Rumen pool
Fluid phase	n.d.^◊	n.d.	-	-
Small particulate phase	0.30	n.d.	-	-
Large particulate phase	0.36	n.d.	-	-
Omasum + abomasum	0.22	n.d.	-	-
Jejunum	0.05	n.d.	-	-
Colon	0.13	n.d.	-	-
Rectum	0.07	n.d.	-	-

Notes: Data are presented as treatment means, n = 4 animals; ^#DM, dry matter; ^†SEM, standard error of the mean; ^§Calculated with respective fractions [%] of omasal and abomasal digesta on a dry matter basis; ^¶The sum of InsP₅ isomers; ^‡<LOQ, not quantifiable; ^◊n.d., not detectable.

Table 4. Concentrations of myo-inositol in digestive tract contents [g/kg DM^#] and blood plasma [µg/ml] of wethers fed diets containing rapeseed meal (Diet RSM) or soybean meal (Diet SBM).

	Diet RSM	Diet SBM	SEM^†	p-Value
Omasum + abomasum^§	0.05	0.02	0.018	0.386
Jejunum	0.99	0.72	0.120	0.162
Blood plasma	4.6	3.8	0.24	0.060

Notes: Data are presented as treatment means, n = 4 animals; ^#DM, dry matter; ^†SEM, standard error of the mean; ^§Calculated with respective fractions [%] of omasal and abomasal digesta on a dry matter basis.

Figure 1. Amount of ruminal (p = 0.007) and total tract (p = 0.002) degraded InsP₆ from feed in wethers fed diets containing rapeseed meal (Diet RSM) or soybean meal (Diet SBM) [g/d]; data are presented as treatment means (n = 4 animals) with error bars (standard error of the mean) and calculated with differences between intake and omasum + abomasum (ruminal), and intake and rectum (total tract), respectively.

Table 5. Ruminal and post-ruminal InsP₆ disappearance in wethers fed diets containing rapeseed meal (Diet RSM) or soybean meal (Diet SBM) [%].

	Diet RSM	Diet SBM	SEM^#	p-Value
Ruminal^†	76	89	3.2	0.033
Post-ruminal
Jejunum	88	94	2.9	0.297
Colon	83	92	2.8	0.046
Rectum	82	93	3.0	0.057
Total post-ruminal^§	6	4	1.2	0.186

Notes: Data are presented as treatment means, n = 4 animals; ^#SEM, standard error of the mean; ^†Calculated with respective InsP₆ disappearance in fractions of omasum and abomasum on a dry matter basis; ^§Calculated as the difference between total tract (rectum) and ruminal disappearance.