Fishmeal is trusted as the most reliable protein source due to its high nutritional quality in terms of palatability and digestibility, and also having excellent nutrient profiles to fulfill the dietary requirement of cultured species. Favorability of fishmeal spurring the aquaculture sector to utilize >70% of global production (FAO, 2015), though aqua feed contributes only about 4-4.5% in total industrial feed production (900 to 1000 million tons in 2015) (Aitech Survey, 2015). The occurrence of El-Nino and other climatic events reduced fishmeal availability by 25% in 2017 (4707 thousand metric tons) compared to the 1990s (6206 thousand metric tons) by affecting the growth, physiology, and reproduction of pelagic fishes, which are mainly used for fishmeal production (US Department of Agriculture, 2018). This increased fishmeal demand from 0.38 to 1.97 million tons and lead to an increase in the cost of fishmeal from 452-755 USD/metric ton (1990s) to 1853 USD/metric ton (2018). Hence, searching for alternatives to fishmeal is an imperative task for researchers for sustaining the growth rate of aquaculture.
Considerable attention has already been devoted to the replacement of fishmeal by using various plant and animal origins in the last two decades but none of the ingredients showed better or equal results to fishmeal due to variation in the nutritional composition of ingredients. Animal proteins have been used extensively in the animal feed industry, but the higher lipid and ash content, fairly poor digestibility, and variation in the quality and sustainability limit their usage in aqua feeds, in particular, shrimp feeds. In addition, the restriction on using rendered animal protein in animal feeding in a number of countries could also be a reason for their limited usage (European Community, 2002).
Table 1 The global production (1000 MT) of fishmeal and oil meals/cakes from 1990 to 2017 (United State Department of Agriculture, 2018)
Year
|
Fishmeal
|
Soybean
meal
|
Groundnut
oil cake
|
Rapeseed
meal
|
Sunflower
oil cake
|
1990
|
5885
|
58212
|
4706
|
10178
|
6676
|
1991
|
5551
|
61223
|
4697
|
10915
|
6377
|
1992
|
5191
|
64264
|
5033
|
10418
|
6245
|
1993
|
6470
|
70195
|
5209
|
10758
|
5977
|
1994
|
5870
|
74939
|
5902
|
11784
|
6943
|
1995
|
5885
|
76955
|
5644
|
13244
|
7586
|
1996
|
6128
|
78117
|
6084
|
12971
|
7076
|
1997
|
5378
|
85232
|
5443
|
13574
|
7012
|
1998
|
5579
|
93438
|
5835
|
13443
|
7775
|
1999
|
5809
|
106879
|
5327
|
21685
|
10645
|
2000
|
6206
|
115827
|
5720
|
20646
|
9262
|
2001
|
5708
|
124599
|
6352
|
19444
|
8337
|
2002
|
4790
|
129959
|
5847
|
18383
|
9036
|
2003
|
5539
|
128621
|
6310
|
21331
|
10291
|
2004
|
5523
|
138302
|
6230
|
23712
|
10060
|
2005
|
4853
|
146134
|
6017
|
26221
|
11634
|
2006
|
5006
|
153759
|
5503
|
25596
|
11644
|
2007
|
5065
|
158962
|
5954
|
27379
|
10907
|
2008
|
4984
|
152329
|
6142
|
30295
|
12952
|
2009
|
3998
|
165518
|
5831
|
32976
|
13227
|
2010
|
5103
|
174657
|
6384
|
33688
|
13200
|
2011
|
4263
|
180910
|
6402
|
35197
|
15555
|
2012
|
4605
|
181190
|
6590
|
36447
|
14085
|
2013
|
4072
|
189899
|
6851
|
38689
|
16863
|
2014
|
4293
|
207352
|
6679
|
39093
|
16175
|
2015
|
4354
|
217820
|
6558
|
39040
|
16322
|
2016
|
4486
|
225617
|
6953
|
39657
|
18349
|
2017
|
4707
|
242708
|
7476
|
40338
|
20514
|
On another hand, the wide availability, reasonable price, and reliable nutrient content made interest in plant proteins, in particular, oilseed meal/cakes. They are the byproducts of oil industries obtained after oil extraction from the respective seeds and are rich in protein content (25-50%). They have been mainly used in all classes of livestock animals and are widely available worldwide (Table 1 and 2). Of all the oil cakes, the global production of soybean meal (SBM) was higher (217820 thousand metric tons), while the least value was noticed for groundnut oil cake (GNC) (6558 thousand metric tons). China is the leading producer for SBM and GNC. The higher production of rapeseed meal (RSM) and sunflower oil cake (SFC) was led by EU-27 and Ukraine respectively, while India is accounting for about 3, 18, 9, and 1% of global production. However, the associated constraints such as higher content of anti-nutrients and fiber fractions, and poor essential amino acids diminish their utilization by affecting palatability and digestibility.
Numerous methodologies have been invented in recent times to overcome the associated constraints completely or partially, but all the techniques have not shown a positive response due to various drawbacks such as loss of essential nutrients, commercial infeasibility, environmental pollution, etc., (Shi et al., 2015). Such drawbacks are very less with fermentation and in addition, an improvement in nutrient quality, due to microbial synthesis, showed a positive response to fermentation (Wee, 1991). The fermented plant proteins have been used as a potential alternative to fishmeal and their utilization was previously documented in shrimp (Jannathulla et al., 2018a; 2019; Dayal et al., 2020), fish (Mukhopadhyay et al., 1999), broilers (Feng et al., 2007), and piglets (Feng et al., 2007). Nonetheless, the greater part of earlier reports has been confined in assessing the degree of success of fermented ingredients. But the economics of this methodology is not much addressed. Hence, the present study is aimed to derive the economic viability of solid-state fermentation (SSF) using our earlier reports. This result would provide a baseline date to evaluate the economic performance of SSF in large-scale processes.
Though oil cakes have been accepted as a major protein source for livestock and poultry feed industries, their utilization was limited in aqua feed especially for shrimp due to poor feeding value. Hence, in our earlier studies four plant protein sources viz., SBM, GNC, RSM, and SFC were treated by the fungus, Aspergillus niger, and their utilization was evaluated in the diet of Penaeus vannamei. A feeding trial was performed with two sets of experimental diets for each ingredient containing untreated and fermented oil cakes. SBM was serially included at 20 (control), 25, 30, 35 and 40% in test diets by replacing fishmeal (w/w) (Jannathulla et al., 2018a), while the other ingredients (GNC, RSM and SFC) were incorporated at 0 (control), 2.5, 5, 7.5 and 10% (Jannathulla et al., 2017: 2018a: 2018b). Results revealed that the inclusion level of plant proteins was significantly (P<0.05) increased after fermentation (2.5-35%) than the respective untreated ones (2.5-25%). The maximum fishmeal replacement could be noticed in fermented SBM (60%) followed by fermented GNC (40%), fermented RSM (30%), and fermented SFC (20%), while the range of replacement was 10-40% for the untreated ingredients.
Table 2 The global production of fishmeal and oilseed meals/cakes in 2017 by the top ten countries (United State Department of Agriculture, 2018)
Fishmeal
|
Soybean meal
|
Groundnut oil cake
|
Rapeseed meal
|
Sunflower oil cake
|
Country
|
1000MT
|
Country
|
1000MT
|
Country
|
1000MT
|
Country
|
1000MT
|
Country
|
1000MT
|
Peru
|
750
|
China
|
68900
|
China
|
3620
|
EU-27
|
13110
|
Ukraine
|
5476
|
EU-27
|
460
|
USA
|
41980
|
India
|
1220
|
China
|
9998
|
EU-27
|
4018
|
Chile
|
430
|
Argentina
|
34350
|
Myanmar
|
325
|
Canada
|
4680
|
Russia
|
3900
|
Thailand
|
430
|
Brazil
|
31350
|
Sudan
|
260
|
India
|
3366
|
Argentina
|
1290
|
China
|
400
|
EU-27
|
10902
|
Nigeria
|
245
|
Japan
|
1360
|
China
|
720
|
USA
|
345
|
India
|
6080
|
Tanzania
|
160
|
USA
|
955
|
Turkey
|
685
|
Japan
|
190
|
Mexico
|
3385
|
USA
|
159
|
Mexico
|
885
|
S. Africa
|
312
|
Russia
|
145
|
Paraguay
|
3300
|
Argentina
|
115
|
Pakistan
|
585
|
USA
|
290
|
Vietnam
|
140
|
Russia
|
3231
|
Burkina
|
90
|
Russia
|
565
|
India
|
187
|
Iceland
|
133
|
Bolivia
|
2140
|
Brazil
|
66
|
Australia
|
442
|
Serbia
|
166
|
Others
|
733
|
Others
|
21376
|
Others
|
622
|
Others
|
1698
|
Others
|
891
|
Total
|
4156
|
Total
|
226994
|
Total
|
6882
|
Total
|
37644
|
Total
|
17935
|
1000MT – 1000 metric tons
|
The primary reason for searching for fishmeal alternates is for economics which reduces production cost by reducing feed cost since feed constitutes about 50-70% of the total cost of production. The economics of feed production is mainly based on the efficiency of the system and the raw materials used for feed formulation. The cost of the raw material will be varied throughout the year based on availability; therefore, developing a strategy to purchase ingredients is imperative to the nutritionist. There are certain things to recognize during the selection of ingredients. They are cost, receiving time/local availability, and the influence of ingredients for feed quality, density, and palatability. But the selection of the ingredients is purely based on the quality and quantity of nutrients present in such ingredients and the nutrient requirements of the cultured species. The cost of the ingredients used in our earlier studies was collected from three feed mills in India (Table 3) and the average was taken to calculate the feed economics here.
Though SSF appears to have a positive effect in enriching the nutrient content, about 10 to 15% of dry matter (DM) loss could be noticed during fermentation due to nutrient utilization by microorganisms. For example, 1 kg of raw materials used for fermentation was reduced to 0.85 kg at the end of the process, thus to produce 1 kg of fermented ingredients approximately 1.2 kg of raw material is required. So, the cost of 1.2 kg was considered as the primary cost to produce 1 kg of fermented ingredients. Therefore, the cost (INR/kg) of the raw materials of SBM, GNC, RSM, and SFC increased from 42, 39, 31, and 24 to 49, 39, 31, and 24, respectively. Since the cost for the fermented ingredients is not yet available commercially for most of the ingredients, the cost of the fermented SBM obtained from different distributors (Table 4) was used to derive the approximate cost for other fermented ingredients in an indirect way.
Table 3 Cost of the various feed ingredients collected at three different feed mills in India (Cost as on December 2018)
Ingredients
|
Price (INR/kg)
|
Place 1
|
Place 2
|
Place 3
|
Fishmeal
|
120
|
126
|
115
|
Acetes
|
-
|
-
|
55
|
Squid meal
|
-
|
-
|
100
|
Soybean meal
|
42
|
39
|
44
|
Corn gluten
|
-
|
69
|
60
|
Wheat gluten
|
-
|
-
|
163
|
Groundnut oil cake
|
32
|
32
|
34
|
Rapeseed meal
|
23
|
27
|
27
|
Sunflower oil cake
|
20
|
20
|
-
|
Guar meal
|
28
|
-
|
36
|
Sesame oil cake
|
20
|
21
|
20
|
Wheat
|
22
|
22
|
23
|
Fish oil
|
103
|
115
|
95
|
Soy-lecithin
|
62
|
65
|
80
|
Palm oil
|
-
|
-
|
50
|
Vitamin mineral Mix
|
92
|
-
|
270
|
Binder
|
92
|
-
|
90
|
Butylated hydroxy toluene
|
1380*
|
-
|
-
|
*From Sisco Research Laboratory
|
The cost of the commercial fermented SBM is varied within as well as between the distributors (Table 4). This could be due to the variation in the nutritional quality of ingredients. Hence, the average was taken within the distributor and among the averages, the highest value was considered as a cost of fermented SBM to reduce the percentage of error. The cost of the selected commercial fermented SBM is increased by 11% more than the primary cost of the untreated SBM used in our earlier study. In addition to the 11% hike, another 4% hike was included for unaccountable things. So, totally 15% hike was added to the primary cost of the respective untreated materials and was considered as the final cost of the fermented ingredients in the present study.
Table 4 Cost of the commercial fermented soybean meal collected from different distributors (https://www.alibaba.com/showroom/fermented-soybean-meal.html) to derive the cost for other fermented ingredients used in the present study
Distributors
|
Price of commercial fermented soybean meal (INR/kg)
|
Minimum price
|
Maximum price
|
Average
|
1
|
26.4
|
33.0
|
29.7
|
2
|
25.1
|
26.4
|
25.7
|
3
|
42.9
|
66.0
|
54.5
|
4
|
39.6
|
59.4
|
49.5
|
5
|
23.1
|
27.1
|
25.1
|
6
|
26.4
|
36.3
|
31.4
|
7
|
23.1
|
27.1
|
25.1
|
8
|
36.3
|
39.6
|
38.0
|
9
|
19.8
|
23.1
|
21.5
|
10
|
50.2
|
59.4
|
54.8
|
11
|
36.3
|
56.1
|
46.2
|
12
|
33.6
|
39.5
|
36.5
|
13
|
49.5
|
59.4
|
54.5
|
14
|
36.3
|
72.6
|
54.5
|
15
|
37.0
|
38.9
|
38.0
|
16
|
46.2
|
59.4
|
52.8
|
17
|
36.3
|
42.9
|
39.6
|
Ingredients
|
Cost of the
raw materials
|
Primary cost
due to 15% DM loss
|
Cost of fermented
ingredients
|
Soybean meal
|
42
|
49
|
56
|
Groundnut oil cake
|
33
|
39
|
45
|
Rapeseed meal
|
26
|
31
|
36
|
Sunflower oil cake
|
20
|
24
|
28
|
Price as on December 2018
|
The economic efficiency of SSF by replacing fishmeal is given in Table 5. The best-performed diets in both untreated and fermented ingredients were selected from each ingredient tested (Jannathulla et al., 2017: 2018a; 2018b) and their formulation cost was compared with the control diet. The total formulation cost of the control diet was high (INR 63.5/kg) and was gradually decreased with increasing fishmeal replacement by using both untreated and fermented plant proteins (INR 57.4-61.8/kg), while the diets containing fermented plant proteins resulted in a better reduction in formulation cost (INR 3.5-6.1/kg) than the diets containing respective untreated materials (INR 1.5-3.0/kg). This could be due to the higher substitution of dietary fishmeal by using fermented ingredients. Though fermented SBM has been found to be incorporated at the highest level by replacing 60% of fishmeal, the cost of reduction was comparatively high with fermented GNC, which showed 40% fishmeal replacement and could be due to the difference in the raw material cost. The cost of reduction was INR 1.5 and 1.7/kg for untreated RSM and SFC, respectively, and the reduction was increased to INR 4.6 and 3.5/kg due to fermentation.
Though complete replacement of fishmeal is not possible in shrimp feed, SSF paves a way to replace the considerable quantity of fishmeal which is quite important industrially nowadays for sustaining the growth rate of aquaculture. As replacing fishmeal using fermented ingredients would be high than the untreated one, the present work suggests for further studies to substitute the dietary fishmeal using a combination of fermented plant mixers to maximize the utilization of plant proteins which not only reduces fishmeal demand and also reduces the feed formulation cost in a better way thereby reducing the total production cost considerably.
Table 5 The cost reduction due to fishmeal replacement by using raw and fermented plant protein sources
Particulars
|
Experimental diets
|
Control
Diet1
|
Soybean meal
|
Groundnut oil cake
|
Rapeseed meal
|
Sunflower oil cake
|
SBM252
|
FSBM353
|
GNC2.54
|
FGNC105
|
RSM2.56
|
FRSM7.57
|
SFC2.58
|
FSFC59
|
Formulation cost (INR/kg)
|
63.5
|
60.6
|
57.9
|
60.5
|
57.4
|
62.0
|
58.9
|
61.8
|
60.0
|
Cost reduction (INR/kg)10
|
-
|
2.9
|
5.6
|
3.0
|
6.1
|
1.5
|
4.6
|
1.7
|
3.5
|
Cost difference (INR/kg)11
|
-
|
-
|
2.7
|
-
|
3.1
|
-
|
3.1
|
-
|
1.8
|
1Diet with no fishmeal replacement
2Diet contained 25% untreated soybean meal by replacing fishmeal (w/w)
3Diet contained 35% fermented soybean meal by replacing fishmeal (w/w)
4Diet contained 2.5% untreated groundnut oil cake by replacing fishmeal (w/w)
5Diet contained 10% fermented groundnut oil cake by replacing fishmeal (w/w)
6Diet contained 2.5% untreated rapeseed meal by replacing fishmeal (w/w)
7Diet contained 7.5% fermented rapeseed meal by replacing fishmeal (w/w)
8Diet contained 2.5% untreated sunflower oil cake by replacing fishmeal (w/w)
9Diet contained 5% fermented sunflower oil cake by replacing fishmeal (w/w)
10Cost of reduction due to the replacement of fishmeal (w/w) using alternative protein sources
11Money saved due to the inclusion of fermented ingredients compared to the respective untreated ones
|