Effects of enzymolytic soybean meal on the growth performance, digestive enzyme activity, some serum indexes, carcase performance and meat quality of Rex rabbits

Figures & data

Table 1. Nutrient composition and biochemical characteristics of SBM and ESBM.

Items	SBM	ESBM
Nutrient composition, %
Dry matter	89.47	90.90
Ash	6.20	8.04
Gross energy	19.51	19.33
Crude fibre	5.15	4.94
Crude protein	46.33	45.49
Ether extract	1.10	0.51
Calcium	0.61	0.46
Total phosphorus	0.57	0.62
Biochemical characteristics
Small peptide, %	0.68	14.94
Glycinin, mg/g	104.77	2.06
β-conglycinin, mg/g	47.12	3.35

SBM: soybean meal; ESBM: enzymolytic soybean meal.

Table 2. Composition and nutrient levels of the experimental diets (air-dry basis).

Items	Control	T1	T2	T3
Ingredients, %
Corn	8.00	8.00	8.00	8.00
Wheat bran	33.00	33.00	33.00	33.00
Soybean meal	11.00	10.50	10.00	9.50
Enzymolytic soybean meal	0.00	0.50	1.00	1.50
Wheat middlings	4.00	4.00	4.00	4.00
Peanut seedling	15.00	15.00	15.00	15.00
Peanut shell	12.50	12.50	12.50	12.50
DL-methionine	0.15	0.15	0.15	0.15
Stone powder	1.05	1.05	1.05	1.05
L-Lysine Sulphate	0.30	0.30	0.30	0.30
Salt	0.50	0.50	0.50	0.50
Calcium hydrogen phosphate	0.50	0.50	0.50	0.50
Rice bran	5.00	5.00	5.00	5.00
Wormwood leaf powder	8.00	8.00	8.00	8.00
Premix^a	1.00	1.00	1.00	1.00
Nutrient levels^b
Digestible energy, MJ/kg	10.92	10.40	10.72	10.58
Dry matter, %	88.83	88.58	89.00	88.86
Crude protein, %	15.49	15.53	15.86	16.52
Ash, %	11.96	12.30	12.18	12.62
Ether extract, %	3.16	2.87	3.21	3.31
Crude fibre, %	14.75	14.53	14.18	14.17
Calcium, %	1.50	1.60	1.68	1.71
Total phosphorus, %	0.70	0.70	0.70	0.73

^aPremix provides the following (per kg of the premix): VA 10,000 IU, VB₁ 2 mg, VB₂ 6 mg, VB₃ 50 mg, VB₄ 1,000 mg, VB₅ 50 mg, VB₆ 2 mg, VB₇ 0.2 mg, VB₁₂ 0.02 mg, VD 900 IU, VE 50 mg, VK 2 mg, Cu (as copper sulphate) 20 mg, Fe (as ferric sulphate) 70 mg, Mn (as manganese sulphate) 10 mg, Zn (as zinc sulphate) 70 mg, Se (as sodium sulphate) 0.25 mg, Co (as cobalt sulphate) 0.15 mg, I (as iodine sulphate) 0.2 mg.

^bDigestible energy was a calculated value, while the others were measured values.

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Table 3. Effect of enzymolytic soybean meal on the growth performance of Rex rabbits (n = 30).

Items	Control	T1	T2	T3	SEM	p-Value
Initial body weight, g	784.22	777.95	770.52	753.37	12.30	0.851
Final body weight, g	1931.50	2000.00	2046.43	2042.79	22.64	0.276
ADFI, g	107.64	112.83	111.55	111.69	1.28	0.544
ADG, g	20.49	21.82	22.78	23.03	0.35	0.052
Feed/gain	5.28^a	5.21^ab	4.96^bc	4.87^c	0.05	0.018

ADFI: average daily feed intake; ADG: average daily gain; Feed/gain: the feed to gain ratio.

^a,b,cMeans in a row without the same superscript are different significantly (p < 0.05).

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Table 4. Effect of enzymolytic soybean meal on gastrointestinal digestive enzyme activity of Rex rabbits (n = 6).

Items	Control	T1	T2	T3	SEM	p-Value
Pepsin, U/mL	14.76	20.48	22.24	20.24	1.72	0.437
Jejunum
α-Amylase, U/mL	262.87	289.65	323.21	317.65	15.95	0.549
Trypsin, U/mL	279.72	271.90	277.84	296.89	8.86	0.805
Lipase, U/L	610.61	652.91	585.23	678.22	22.28	0.505
Caecum
α-Amylase, U/mL	387.96^b	389.12^b	402.89^b	438.17^a	7.06	0.025
Trypsin, U/mL	281.61^b	288.81^b	307.91^b	357.45^a	8.14	<0.001
Lipase, U/L	555.45	557.66	568.35	696.56	21.40	0.063
Cellulase, U/mL	262.28	270.05	266.97	296.90	6.70	0.207

^a,bMeans in a row without the same superscript are different significantly (p < 0.05).

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Table 5. Effect of enzymolytic soybean meal on serum biochemical and immune indexes of Rex rabbits (n = 6).

Items	Control	T1	T2	T3	SEM	p-Value
TP, μg/mL	744.21	793.65	787.63	781.10	13.72	0.625
ALB, ng/mL	140.42^bc	148.76^b	124.76^c	171.48^a	4.95	<0.001
IgA, μg/mL	2542.74	2567.72	2280.96	2440.54	104.46	0.791
IgG, g/L	30.59	24.24	28.53	31.10	1.28	0.269
IgM, μg/mL	869.26	761.45	962.52	901.31	53.42	0.683
C3, μg/mL	237.20	231.86	213.83	254.33	10.12	0.588
C4, μg/mL	342.12	393.56	430.06	386.45	21.33	0.630
Lysozyme, U/L	11.23^b	17.59^a	17.30^a	18.77^a	0.89	<0.001

TP: total protein; ALB: albumin; IgA: immunoglobulin A; IgG: immunoglobulin G; IgM: immunoglobulin M; C3: complement 3; C4: complement 4.

^a,b,cMeans in a row without the same superscript are different significantly (p < 0.05).

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Table 6. Effect of enzymolytic soybean meal on immune organ indexes of Rex rabbits (n = 6).

Items	Control	T1	T2	T3	SEM	p-Value
Spleen index, g/kg	0.52	0.35	0.51	0.39	0.05	0.530
Thymus index, g/kg	1.89	1.71	2.15	2.21	0.14	0.600
Sacculus rotundus index, g/kg	1.31	1.11	1.15	1.14	0.05	0.567

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Table 7. Effect of enzymolytic soybean meal on the carcase performance of Rex rabbits (n = 6).

Items	Control	T1	T2	T3	SEM	p-Value
Pre-slaughter weight, g	1748.33^b	1900.00^a	2003.83^a	1890.83^a	26.02	0.001
Slaughter ratio, %	68.68	69.73	68.96	67.25	0.34	0.058
Full eviscerated slaughter ratio, %	53.87^b	56.54^a	55.65^ab	53.85^b	0.41	0.029
Half eviscerated slaughter ratio, %	57.32^b	59.72^a	58.31^ab	57.01^b	0.37	0.022

^a,bMeans in a row without the same superscript are different significantly (p < 0.05).

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Table 8. Effect of enzymolytic soybean meal on the meat quality of Rex rabbits (n = 6).

Items	Control	T1	T2	T3	SEM	p-Value
pH45min	6.67	6.58	6.66	6.67	0.03	0.789
pH24h	5.57	5.57	5.57	5.59	0.01	0.751
Cooking loss, %	28.83	27.59	28.58	26.71	0.41	0.307
Shear force, kg·f	2.89	2.78	2.82	2.43	0.11	0.504
L*	24.26	25.91	24.72	23.38	0.50	0.388
a*	4.40	3.76	4.44	4.85	0.51	0.911
b*	2.09	2.82	2.78	3.03	0.27	0.680

pH_45min: pH at 24 h post slaughter; pH_24h: pH at 45 min post slaughter; L*: lightness; a*: redness; b*: yellowness.

T1 means 0.5% enzymolytic soybean meal addition group, T2 means 1.0% enzymolytic soybean meal addition group, and T3 means 1.5% enzymolytic soybean meal addition group.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.