Ether extract and acid detergent fibre but not glucosinolates are determinants of the digestible and metabolizable energy of rapeseed meal in growing pigs

Figures & data

Table 1. Sources of rapeseed meal used in the experiments.

Numbers	Sources within China	GLS, μmol/g
1	Hubei	10.19
2	Shandong	19.66
3	Jiangsu	28.94
4	Jiangsu	5.87
5	Sichuan	25.09
6	Anhui	1.74
7	Hunan	3.10
8	Hunan	3.54
9	Sichuan	4.20
10	Anhui	5.54
11	Hunan	5.96
12	Hubei	6.16
13	Yunnan	10.45
14	Jiangsu	11.07
15	Jiangsu	11.67
16	Chengdu	13.88
17	Sichuan	17.54
18	Hubei	28.31
19	Henan	33.67
20	Hubei	43.10
21	Sichuan	48.13
22	Shanxi	62.94

Table 2. Chemical compositions of rapeseed meals (DM basis).

Items	GLS, μmol/g	DM, %	GE, MJ/kg	CP, %	EE, %	NDF, %	ADF, %	CF, %	Ash, %
1	10.19	89.75	19.97	41.52	3.35	46.44	26.71	17.40	8.18
2	19.66	90.32	19.91	43.36	1.94	51.96	35.71	17.50	8.48
3	28.94	89.56	19.57	40.88	2.18	39.59	24.45	15.88	9.06
4	5.87	89.20	19.82	42.26	2.10	36.45	24.04	15.95	7.52
5	25.09	89.73	18.30	42.24	1.42	41.99	25.44	14.73	8.47
6	1.74	90.86	20.80	39.08	8.98	36.47	23.16	15.89	9.19
7	3.10	91.73	21.15	36.14	10.37	38.45	22.78	16.71	6.97
8	3.54	92.73	22.33	38.71	14.55	48.50	26.17	18.25	6.83
9	4.20	90.57	21.06	41.48	6.94	48.85	30.39	18.62	7.40
10	5.54	92.17	21.51	40.07	10.44	54.12	36.13	23.24	7.81
11	5.96	92.21	20.93	39.76	7.88	52.30	32.64	19.01	8.30
12	6.16	91.59	21.06	38.13	9.01	55.38	32.00	25.79	6.80
13	10.45	92.47	21.87	39.52	11.26	49.95	32.77	22.86	7.01
14	11.07	92.17	20.76	40.13	7.02	36.70	22.42	17.23	6.91
15	11.67	91.60	21.66	38.34	9.31	54.26	33.68	22.53	7.15
16	13.88	91.19	20.98	42.90	6.77	46.47	25.95	17.15	6.66
17	17.54	92.05	21.14	41.13	8.21	57.14	36.14	27.80	4.67
18	28.31	86.69	22.87	42.08	12.25	57.37	34.43	28.58	8.27
19	33.67	91.69	21.55	38.07	11.18	42.10	25.14	18.48	7.56
20	43.10	91.36	21.04	36.04	8.54	47.49	25.01	15.81	6.22
21	48.13	91.90	21.04	35.72	9.24	48.62	27.88	23.39	7.30
22	62.94	91.77	21.10	41.32	8.28	47.24	28.39	18.56	7.68
Mean	18.21	91.06	20.92	39.94	7.78	47.17	28.79	19.60	7.47
CV	88.96	1.51	4.56	5.44	45.16	14.01	15.94	20.24	13.17

Note: TGS, total glucosinolates; DM, dry matter; GE, gross energy; CP, crude protein; EE, ether extract; NDF, neutral detergent fibre; ADF, acid detergent fibre; CF, crude fibre.

Table 3. Ingredient compositions of the experimental diets (%, as-fed basis).

Ingredients	Basal diet	Tested diets
Corn	96.90	67.83
Rapeseed meal	–	29.07
Dicalcium phosphate	1.70	1.70
Salt	0.30	0.30
Limestone	0.60	0.60
Micromineral and vitamin premix^a	0.50	0.50
Total	100.00	100.00

^aProduct of the Chemical Reagents Company (Beijing, China).

Premix provided the following per kg of the complete diet: vitamin A as retinyl acetate, 5,512 IU; vitamin D₃ as cholecalciferol, 2,200 IU; vitamin E as DL-alpha-tocopheryl acetate, 30 IU; vitamin K₃ as menadione nicotinamide bisulphite, 2.2 mg; vitamin B₁₂, 27.6 μg; riboflavin, 4 mg; pantothenic acid as DL-calcium pantothenate, 14 mg; niacin, 30 mg; choline chloride, 400 mg; folacin, 0.7 mg; thiamin as thiamine mononitrate, 1.5 mg; pyridoxine as pyridoxine hydrochloride, 3 mg; biotin, 44 μg; Mn as MnO, 40 mg; Fe as FeSO₄•H₂O, 75 mg; Zn as ZnO, 75 mg; Cu as CuSO₄•5H₂O, 100 mg; I as KI, 0.3 mg; Se as Na₂SeO₃, 0.3 mg.

Table 4. Analyzed nutrient levels of diets (DM basis).

Items	DM, %	GE, MJ/kg	CP, %	EE, %	NDF, %	ADF, %	CF, %	Ash, %	GLS, μmol/g
1	87.76	18.52	19.25	2.62	27.59	12.31	7.71	5.88	2.96
2	87.54	18.92	19.11	4.40	24.67	9.05	7.29	5.52	5.72
3	87.80	18.96	18.15	4.81	24.26	10.33	6.54	5.87	8.41
4	86.85	18.78	18.49	1.88	23.29	9.43	6.24	6.25	1.71
5	87.90	19.43	17.55	7.29	21.22	7.49	6.63	5.63	7.29
6	87.66	19.30	17.45	6.24	22.64	8.97	6.71	5.57	0.51
7	87.73	19.25	18.60	4.15	24.06	7.93	5.87	5.93	0.90
8	87.53	18.92	17.94	3.76	23.16	8.40	5.59	6.29	1.03
9	87.64	19.19	18.10	5.73	23.53	10.90	6.97	5.61	1.22
10	87.52	18.70	17.28	5.16	24.84	8.94	6.84	5.39	1.61
11	87.91	19.32	18.11	6.25	25.25	10.53	7.16	5.36	1.73
12	87.10	19.14	18.38	3.56	24.86	10.13	6.22	5.37	1.79
13	87.04	19.30	17.73	4.81	24.48	9.87	6.14	5.12	3.04
14	87.54	19.15	16.77	5.85	23.55	7.77	5.72	5.59	3.22
15	87.81	17.13	18.27	3.25	24.05	9.44	5.73	5.32	3.39
16	87.48	19.39	17.16	4.02	25.30	9.71	6.44	5.27	4.03
17	87.94	19.07	18.44	4.74	23.00	7.51	5.50	5.16	5.10
18	87.51	19.11	17.70	5.45	23.76	10.08	6.22	5.76	8.23
19	86.57	18.72	18.74	1.57	19.97	8.83	5.91	5.16	9.79
20	86.63	18.75	19.03	2.24	20.15	8.09	6.26	5.68	12.53
21	87.66	19.27	18.65	5.57	22.37	10.00	7.29	5.60	13.99
22	87.30	19.51	18.34	5.50	22.06	9.47	7.17	3.84	18.30
Basal diet	85.91	18.76	9.09	1.79	13.01	2.85	2.68	6.01	0.00

Note: DM, dry matter; GE, gross energy; CP, crude protein; EE, ether extract; NDF, neutral detergent fibre; ADF, acid detergent fibre; CF, crude fibre. GLS, glucosinolates.

Table 5. Digestible (DE) and metabolizable energy (ME) of rapeseed meal, and apparent total tract digestibility (ATTD) of GE in diets (DM basis) digestibility (ATTD) of GE in diets (DM basis).

Items	DE, MJ/kg	ME, MJ/kg	ME/DE	ATTD of GE, %
1	13.60^bcde	12.34^ab	0.96	81.66^abc
2	10.10^f	9.09^c	0.97	78.16^e
3	11.82^e	10.83^bc	0.97	80.97^bcd
4	13.17^cde	11.41^bc	0.95	82.91^ab
5	13.35^cde	11.76^bc	0.96	82.94^ab
6	13.91^abcd	13.48^ab	0.98	82.85^ab
7	14.56^abc	13.70^ab	0.97	83.12^ab
8	15.41^a	13.98^ab	0.96	83.16^ab
9	13.16^cde	11.69^bc	0.96	81.06^bcd
10	11.77^e	10.97^bc	0.97	78.47^ed
11	12.43^de	10.96^bc	0.96	80.36^bcde
12	13.23^cde	12.12^ab	0.97	81.18^bcd
13	13.76^abcd	11.88^bc	0.95	80.95^bcd
14	15.28^ab	14.94^a	0.98	84.34^a
15	13.56^bcde	12.62^ab	0.97	81.31^bcd
16	13.16^cde	11.11^bc	0.95	81.75^abc
17	12.64^de	11.68^bc	0.97	79.53^cde
18	14.56^abc	13.45^ab	0.97	81.22^bcd
19	14.06^abcd	12.94^ab	0.97	81.53^abc
20	12.43^de	11.38^bc	0.97	81.54^abc
21	13.45^cde	12.57^ab	0.97	80.45^bcde
22	14.59^abc	12.93^ab	0.96	82.56^abc
Max	15.41	14.94	0.98	84.34
Min	10.10	9.09	0.95	78.16
Mean	13.36	12.17	0.97	81.45
SEM	0.38	0.59	0.07	0.62
P Value	< 0.01	< 0.01	0.15	< 0.01

Note: Means in the same column bearing different superscripts differ significantly (P < 0.05).

Table 6. Correlation coefficients between digestible and metabolizable energy and chemical compositions of rapeseed meals.

Items	DE	ME	GE	CP	EE	NDF	ADF	CF	Ash	GLS
DE	1.00
ME	0.94**	1.00
GE	0.42	0.42	1.00
CP	−0.27	−0.4	−0.35	1.00
EE	0.53*	0.55**	0.92**	−0.56**	1.00
NDF	−0.28	−0.31	0.48*	0.06	0.34	1.00
ADF	−0.45*	−0.44*	0.35	0.24	0.18	0.91**	1.00
CF	0.03	0.06	0.61**	−0.08	0.50*	0.79**	0.75**	1.00
Ash	−0.17	−0.14	−0.36	0.28	−0.35	−0.31	−0.16	−0.39	1.00
GLS	−0.01	−0.02	−0.04	−0.11	−0.03	0.05	−0.06	0.02	−0.01	1.00

Note: GLS, glucosinolates; DM, dry matter; GE, gross energy; CP, crude protein; EE, ether extract; NDF, neutral detergent fibre; ADF, acid detergent fibre; CF, crude fibre.

*, **represent P < 0.05 and P < 0.01, respectively.

Table 7. Linear regression equations for prediction of energy content based on the chemical compositions of rapeseed meal fed to growing pigs.

NO	Prediction equations	R^2	RMSE^2	P value
1	DE (MJ/kg DM) = 11.96 + 0.18 EE (%)	0.28	1.16	< 0.01
2	DE (MJ/kg DM) = 15.91 + 0.22 EE (%) − 0.15 ADF (%)	0.59	0.82	< 0.01
3	DE (MJ/kg DM) = 8.04 + 0.21 CP (%) + 0.29 EE (%) − 0.18 ADF (%)	0.67	0.75	< 0.01
4	ME (MJ/kg DM) = 10.64 + 0.19 EE (%)	0.30	1.12	< 0.01
5	ME (MJ/kg DM) = 14.82 + 0.23 EE (%) − 0.16 ADF (%)	0.60	0.86	< 0.01

Regression equations were developed by stepwise regression analyses.

CP, crude protein; EE, ether extract; NDF, neutral detergent fibre; ADF, acid detergent fibre.