Digestibility, toxicity and metabolic effects of rapeseed and sunflower protein hydrolysates in mice

Figures & data

Table 1. Chemical composition of ingredients and experimental diets used in the in vitro digestibility trial (% of dry matter).

	Crude protein	Ether extract	Crude ash	NDF	Starch
Rapeseed DSM	32.7 ± 0.1	3.0 ± 0.1	7.0 ± 0.1	36.1 ± 0.8	14.4 ± 0.1
Sunflower DSM	29.8 ± 0.4	0.8 ± 0.1	6.7 ± 0.1	47.2 ± 1.1	3.8 ± 0.5
Rapeseed hydrolysate (RPH)	70.2 ± 1.2	7.4 ± 0.1	13.8 ± 1.2	0.4 ± 0.2	2.0 ± 0.8
Sunflower hydrolysate (SPH)	83.2 ± 1.8	1.1 ± 0.1	14.4 ± 0.8	1.1 ± 1.2	1.9 ± 0.6
Cereal mix (CM)	9.7 ± 0.1	5.1 ± 0.1	2.7 ± 0.1	12.3 ± 0.5	66.0 ± 0.3
CM + Rapeseed DSM^a	20.5	4.1	4.7	25.1	41.7
CM + Sunflower DSM^a	19.6	3.0	4.7	29.5	35.4
CM + RPH^a	26.0	5.9	6.2	8.5	45.1
CM + SPH^a	28.0	4.0	5.6	9.7	48.2

NDF: neutral detergent fibre; DSM: defatted seed meals; CM + rapessed DSM, 5 g cereal mix +4.45 g rapeseed meal; CM + sunflower DSM, 5 g cereal mix +4.85 g sunflower; CM + RPH, 5 g cereal mix +2.43 g rapeseed hydrolysate; CM + SPH, 5 g cereal mix +1.92 g sunflower hydrolysate.

^a Calculated values.

Figure 1. Gel filtration chromatography of the sunflower protein isolate (—) and the final sunflower protein hydrolysate (- - - ) on Superose 12 HR 10/30. Inset: SDS-PAGE of sunflower protein hydrolysates (SPHs); MW, molecular weight markers (kDa).

Figure 2. Gel filtration chromatography of the rapeseed protein isolate (—) and the final rapeseed protein hydrolysate (- - -) on Superose 12 HR 10/30. Inset: SDS-PAGE of rapeseed protein hydrolysates (RPHs); MW, molecular weight markers (kDa).

Table 2. In vitro digestibility (%) of diets containing different sources of protein.

Diet	Dry matter	Organic matter	Crude protein	Ether extract	Crude ash
CM + Rapeseed DSM	72.5b	74.1b	87.1a	95.4b	35.8a
CM + Sunflower DSM	63.4a	64.6a	89.1b	93.8a	37.4b
CM + RPH	90.4c	90.4c	96.1c	97.8d	89.7c
CM + SPH	90.1c	90.2c	96.1c	95.8c	89.0c
Pooled SEM	0.26	0.22	0.06	0.07	0.50

There were four replicates for each treatment. CM + rapessed DSM, 5 g cereal mix +4.45 g rapeseed meal; CM + sunflower DSM, 5 g cereal mix +4.85 g sunflower meal; CM + RPH, 5 g cereal mix +2.43 g rapeseed protein hydrolysate; CM + SPH, 5 g cereal mix +1.92 g sunflower protein hydrolysate. Experimental diets were used in different amounts to ensure that each flask contained the same amount of protein. Within a row, different letters indicate significant differences (p < .05) among diets. CM: cereal mix; DSM: defatted seed meals; RPH: rapeseed hydrolysate; SPH: sunflower hydrolysate.

Table 3. Body weight and food intake in Swiss Albino male mice fed a standard chow diet (control) or a diet containing rapeseed or sunflower protein hydrolysates over 28 days period.

Parameters	Control	RPH	SPH
Body Weight, g
Initial	38.9 ± 4.3	39.4 ± 3.4	40.6 ± 3.4
Final	41.6 ± 5.2	41.4 ± 4.2	43.9 ± 2.0
Weight gain, g	2.7 ± 2.5	2.0 ± 2.3	3.3 ± 1.5
Food intake, g/animal/day	5.9	7.1	6.7

Each value represents the mean ± SD of eight independent experiments on eight mice. Statistical analysis was applied only on body weight data. RPH: standard rodent chow +10% rapeseed protein hydrolysate; SPH: standard rodent chow +10% sunflower protein hydrolysate.

Table 4. Blood biochemistry parameters in Swiss Albino male mice fed a standard chow diet (control) or a diet containing rapeseed or sunflower protein hydrolysates.

Parameters	Control	RPH	SPH
ALT, U/L	158 ± 11	161 ± 13	152 ± 14
Creatinine, mg/dL	0.34 ± 0.02	0.34 ± 0.02	0.34 ± 0.03
Glucose, mg/dL	32 ± 6	41 ± 8	29 ± 7
Fructosamine, μmol/L	351 ± 23	358 ± 24	350 ± 22
Triglycerides, mg/dL	152 ± 20	159 ± 15	142 ± 12
NEFA, mmol/dL	2.09 ± 0.10	2.11 ± 0.15	2.00 ± 0.13
Total cholesterol, mg/dL	169 ± 12.1	163 ± 14.0	172 ± 16.2
Total protein, g/dL	5.73 ± 0.43	5.71 ± 0.49	5.69 ± 0.44
Albumine, g/dL	3.03 ± 0.02	3.02 ± 0.05	3.01 ± 0.04
Albumine/globulins ratio	1.12	1.12	1.12

Each value represents the mean ± SD of eight independent experiments on eight mice. RPH: standard rodent chow +10% rapeseed protein hydrolysate; SPH: standard rodent chow +10% sunflower protein hydrolysate.

Table 5. Phase I enzymatic activities in the liver and kidney of Swiss Albino male mice fed a standard chow diet (control) or a diet containing rapeseed or sunflower protein hydrolysates.

	Control		RPH		SPH
Parameters	Liver	Kidney	Liver	Kidney	Liver	Kidney
Aminopyrine N-demethylase (CYP3A1/2), nmol mg^−1 min^−1	16.876 ± 0.608	n.d.	25.761 ± 2.684*	n.d.	20.05 ± 0.725*	n.d.
p-Nitrophenol hydroxylase (CYP2E1), nmol mg^−1 min^−1	1.109 ± 0.083	0.605 ± 0.030	1.319 ± 0.026**	0.567 ± 0.010*	1.042 ± 0.111	0.460 ± 0.008**
Ethoxycoumarin O-deethylase (CYP1A1/2, CYP2A, CYP2B, CYP2E1), pmol mg^−1 min^−1	0.746 ± 0.071	n.d.	0.832 ± 0.112	n.d.	0.716 ± 0.065	n.d.
Pentoxyresorufin O-dealkylase (CYP2B1/2), pmol mg^−1 min^−1	4.483 ± 0.275	0.081 ± 0.001	4.693 ± 0.353	0.070 ± 0.005**	5.590 ± 0.390**	0.041 ± 0.009**
Metoxyresorufin O-demethylase (CYP1A2), pmol mg^−1 min^−1	43.030 ± 5.799	0.112 ± 0.023	44.221 ± 4.221	0.093 ± 0.014	62.038 ± 7.103**	0.079 ± 0.016*
Ethoxyresorufin O-deethylase (CYP1A1), pmol mg^−1 min^−1	12.656 ± 0.580	0.037 ± 0.006	11.121 ± 0.478*	0.035 ± 0.008	15.361 ± 0.688**	0.020 ± 0.006**

Each value represents the mean ± SD of eight independent experiments on eight mice.

* Significant difference (p < 0.05) between treated groups and the control;.

** Significant difference (p < 0.01) between treated groups and the control (Wilcoxon’s rank method).

RPH: standard rodent chow +10% rapeseed protein hydrolysate; SPH: standard rodent chow +10% sunflower protein hydrolysate; n.d.: not detectable for detection limits.

Table 6. Phase II enzymatic activities in the liver and kidney of Swiss Albino male mice fed a standard chow diet (control) or a diet containing rapeseed or sunflower protein hydrolysates.

	Control		RPH		SPH
Parameters	Liver	Kidney	Liver	Kidney	Liver	Kidney
Glutatione S-transferase, nmol/mg per min	1.837 ± 0.087	0.546 ± 0.085	1.919 ± 0.114	0.544 ± 0.030	1.914 ± 0.155	0.487 ± 0.055
UDP-gluguronosyl transferase, nmol/mg per min	1.610 ± 0.108	0.286 ± 0.047	1.291 ± 0.174*	0.286 ± 0.076	1.160 ± 0.148*	0.274 ± 0.050

Each value represents the mean ± SD of eight independent experiments on eight mice. RPH: standard rodent chow +10% rapeseed protein hydrolysate; SPH: standard rodent chow +10% sunflower protein hydrolysate.

* Significant difference (p < .05) between treated groups and the control (Wilcoxon’s rank method).