Enhanced Mineral Digestibility, and Tissue Retention in Rainbow Trout (Oncorhynchus Mykiss) Fed Lupin Meal with a Solid-State Fermentation (SSF) Dietary Supplement

Simon J. Davies; Ehab El Haroun; Hien Van Doan; Peter H. Bowyer

doi:10.2478/aoas-2025-0056

Figures & Tables

Histological sections of the 47th–48th vertebrae of fish fed the experimental diets (4 fish per triplicate, total of 12 sampled fish per treatment group). Vertebral and scale morphology, remodelling and mineralisation were then assessed by histomorphometry and colorimetric assays. No significant effects of diet on the measured parameters were detected for the parameters assessed. However, more uniform mineralisation is observed in the centrum region of vertebrae taken for rainbow trout fed the higher SSF SynergenTM diet. This could be due to greater calcium and phosphorous bioavailability

Proteolytic enzyme activities in digesta and mucosa of fish fed the lupin-based diet, with and without SSF (S) inclusions

	Diet

	LC	LS0.1	LS0.5
Digesta
TAP^* (U/g)	17.50±3.75	16.03±1.26	17.71±1.32
Trypsin (U/g)	68.18±21.31	66.97±14.02	65.03±13.89
Chymotrypsin (U/g)	325.50±129.00	290.29±27.89	368.57±98.38
ALP (U/g)	51.64±8.94 a	78.92±17.14 b	79.37±20.56 b
LAP (U/g)	5.91±1.27 a	7.61±2.85 b	8.50±1.06 b
Mucosa
ALP (U/g)	216.73±56.31	203.24±57.98	169.73±68.43
LAP (U/mg)	837.87±225.36	737.07±113.59	692.20±102.33

Tissue mineral concentrations of liver, muscle, vertebrae, and caudal fin in experimental fish with Synergen SSF (S) supplemented lupin diets respectively and fishmeal reference (FMR diet) (± SD)

	Diet

	LC	LS0.1	LS0.5	FMR

1	2	3	4	5
Liver
P (mg/g)	11.72±0.27	11.68±0.45	11.40±0.54	11.64±0.20
K (mg/g)	11.54±1.13	11.56±0.46	11.70±0.31	11.85±0.59
S (mg/g)	8.43±0.56	8.59±0.23	8.58±0.57	8.84±0.34
Na (mg/g)	4.23±0.51	4.29±0.09	4.32±0.31	4.69±0.16
Mg (mg/g)	0.74±0.05	0.77±0.02	0.75±0.04	0.76±0.04
Ca (mg/g)	0.38±0.10	0.46±0.12	0.44±0.29	0.45±0.08
Cu (mg/g)	0.30±0.02	0.28±0.02	0.27±0.02	0.26±0.07
Fe (mg/g)	0.19±0.05	0.17±0.03	0.18±0.02	0.15±0.03
Zn (mg/g)	0.15±0.01 a	0.16±0.02 a	0.16±0.01 a	0.20±0.01 b
Mn (µg/g)	4.12±0.12 a	4.39±0.49 ab	4.90±0.34 b	2.70±0.27 c
Muscle
K (mg/g)	14.73±0.80	14.59±0.30	14.13±0.65	14.97±0.09
P (mg/g)	8.59±0.27	8.59±0.29	8.43±0.17	8.77±0.15
S (mg/g)	7.64±0.05	7.71±0.11	7.64±0.25	8.00±0.27
Na (mg/g)	2.42±0.06	2.38±0.06	2.38±0.09	2.19±0.14
Mg (mg/g)	0.99±0.04	0.98±0.03	0.94±0.02	0.96±0.01
Ca (mg/g)	0.81±0.11	0.98±0.09	1.05±0.24	0.83±0.12
Zn (µg/g)	16.27±0.18	17.41±1.00	17.33±0.68	17.51±0.77
Fe (µg/g)	12.03±1.78	11.98±1.39	11.89±1.82	11.94±1.63
Mn (µg/g)	0.61±0.20 ab	0.77±0.23 a	0.93±0.07 a	0.40±0.18 b
Vertebrae
Ca (mg/g)	93.81±9.01	91.29±6.02	87.50±3.99	90.68±7.73
P (mg/g)	56.69±4.44	55.99±3.00	54.66±2.09	55.88±4.06
Ca:P	1.65±0.03 a	1.63±0.02 b	1.60±0.02 c	1.62±0.02 bc
Na (mg/g)	15.99±0.75	16.11±0.47	16.91±0.13	15.74±0.62
K (mg/g)	7.38±0.85	7.38±0.47	8.06±0.25	7.96±0.69
S (mg/g)	3.30±0.06	3.32±0.08	3.43±0.15	3.44±0.09
Mg (mg/g)	2.11±0.18	2.09±0.07	2.08±0.05	2.02±0.12
Zn (µg/g)	76.68±7.82	85.33±0.72	85.79±12.72	93.95±8.80
Mn (µg/g)	12.30±3.32 a	13.14±0.70 a	14.21±2.25 a	6.23±1.06 b
Caudal fin
Ca (mg/g)	106.90±5.08	103.90±4.67	107.32±2.58	98.90±2.63
P (mg/g)	62.07±4.36	59.73±7.46	58.97±3.73	51.91±4.13
Na (mg/g)	44.62±1.14 ab	33.16±5.51 c	39.14±2.54 bc	48.82±3.21 a
K (mg/g)	5.30±0.28 a	7.41±0.38 b	6.81±0.81 b	5.39±0.24 a
S (mg/g)	5.40±0.06 a	5.32±0.22 a	5.42±0.10 a	5.80±0.05 b
Mg (mg/g)	2.25±0.10 ab	2.36±0.18 a	2.36±0.08 a	2.05±0.05 b
Zn (µg/g)	95.78±7.11	95.15±12.54	104.29±3.86	102.57±6.40
Mn (µg/g)	15.37±3.21 a	16.38±1.21 ab	19.71±2.40 b	8.30±1.33 c

Apparent macronutrient digestibility coefficients (ADC) (%) and apparent mineral bioavailability coefficients (ABAC) (%) of the experimental lupin-based and fishmeal-based rainbow trout diets with SSF (S) (± SD)

	Diet

	LC	LS0.1	LS0.5
ADC (%)
DM	96.97±0.43	96.71±0.21	97.08±0.69
CP	83.65±0.02 a	85.26±0.03 b	85.55±0.03 c
CL	89.11±0.77	88.93±0.10	90.43±0.79
CF	33.99±1.05 a	35.52±1.60 a	44.69±2.62 b
GE	66.29±0.62 a	68.41±0.83 b	71.76±0.15 c
ABAC (%)
Ca	0.67±1.57 a	13.80±1.62 b	20.20±0.77 c
P	55.02±0.72 a	63.86±0.69 b	73.53±0.47 c
Mg	33.43±0.03 a	42.91±0.64 b	51.27±0.45 c
K	92.14±0.05 a	93.30±0.06 b	94.04±0.11 c
S	53.82±0.35 a	58.97±0.37 b	62.00±0.72 c
Fe	41.77±2.19 a	48.34±1.99 b	39.59±0.83 a
Zn	29.39±0.96 a	30.41±2.68 a	41.59±3.96 b

Bone histomorphometric indices of the 47th–48th vertebrae of rainbow trout fed the experimental diets respectively

	Diet

	LC	LS0.1	LS0.5	FMR
CTI	7.04±1.31	7.32±0.43	6.76±0.83	7.88±0.79
VPA	6.72±1.44	6.23±0.87	6.57±0.74	5.99±1.14

Feed formulations, proximate compositions, and element concentrations of the basal and control trout diets with Synergen SSF addition for rainbow trout

	LC (basal)	FMR (fishmeal reference)
Ingredients (g/kg)
Yellow lupin	300.00	0.00
Herring meal¹	250.00	638.62
Soya bean meal²	180.71	0.00
Fish oil³	137.15	119.97
Corn starch⁴	70.14	229.40
Soya protein concentrate⁵	50.00	0.00
Carboxyl-methyl-cellulose⁶	5.00	5.00
Vitamin/mineral premix⁷	5.00	5.00
Ascorbyl-phosphate⁸	1.00	1.00
Yttrium oxide⁹	1.00	1.00
Synergen™ ^**	–	–
Proximate composition (%)
Dry matter (DM)	99.30	99.23
Crude protein (N*6.25)	43.07	44.01
Crude lipid	20.47	19.80
Crude fibre	2.70	–
Ash	6.60	6.70
Gross energy (MJ/kg)	21.66	23.21
Element concentrations
Ca (g/kg)	78.01	157.61
P (g/kg)	80.26	136.17
K (g/kg)	104.30	64.42
Na (g/kg)	44.55	86.67
Mg (g/kg)	17.78	13.40
S (g/kg)	38.05	54.11
Fe (g/kg)	1.58	1.36
Zn (mg/kg)	644.74	777.46
Mn (mg/kg)	801.62	67.86
Cu (mg/kg)	133.56	73.42

Enhanced Mineral Digestibility, and Tissue Retention in Rainbow Trout (Oncorhynchus Mykiss) Fed Lupin Meal with a Solid-State Fermentation (SSF) Dietary Supplement

Figures & Tables

Figure 1.

Proteolytic enzyme activities in digesta and mucosa of fish fed the lupin-based diet, with and without SSF (S) inclusions

Tissue mineral concentrations of liver, muscle, vertebrae, and caudal fin in experimental fish with Synergen SSF (S) supplemented lupin diets respectively and fishmeal reference (FMR diet) (± SD)

Apparent macronutrient digestibility coefficients (ADC) (%) and apparent mineral bioavailability coefficients (ABAC) (%) of the experimental lupin-based and fishmeal-based rainbow trout diets with SSF (S) (± SD)

Bone histomorphometric indices of the 47th–48th vertebrae of rainbow trout fed the experimental diets respectively

Feed formulations, proximate compositions, and element concentrations of the basal and control trout diets with Synergen SSF addition for rainbow trout

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