6.1 Salmon and Trout
6.2 Catfish
6.3 Carps
6.4 Tilapias
6.5 Shrimp and Prawns
6.6 Other Species
In section 4 it was explained that different species have different nutritional requirements. Some methods of making feeds have been described in section 5. There is a considerable amount of published information on the specific requirements of each species; it is more detailed for those species on which most nutritional research has been conducted. Until recently only a few species were grown in intensive culture - these were the ones on which research centred.
In a manual such as this it is only possible to briefly note some characteristics of feeds developed for the major cultivated species: tilapia, carps, catfish, trout, salmon, marine shrimp, freshwater prawns, groupers and sea breams, and rabbitfish, for example. No information has been included on the requirements of eels. For those who wish to study the topic of specific nutritional requirements, 'further reading' is suggested at the end of this section.
A brief summary of the known requirements of each of these species follows, while specific examples of formulations are provided in Appendix II. It is stressed that the examples given in Appendix II are intended to provide an indication of how actual diets are constructed. To some extent, because of the differing local availabilities of ingredients, the formulations given are specific to the location and the time at which they were first developed. Where possible therefore, both the location and the date of each formulation have been quoted. It should be noted that, although some specifications are given in this section for each species, the analytical characteristics of the formulations given in Appendix II do not necessarily comply with them. This is because those who develop practical or commercial feed formulae sometimes amend the specifications according to their own personal experience or because of considerations relating to local conditions and economics.
In the individual sub-sections of this part of the manual which follow, only the major nutrients are covered. Readers are advised to consult the papers listed in 'further reading' at the end of the section, which give full details about the state of nutritional knowledge on each species at the time they were written. New information is constantly emerging, based on research and the result of practical application. Any recommendations given here, and in 'further reading' are therefore subject to amendment in the future.
A level or a range of levels for each major dietary component is quoted in the following sections. As stated before, these levels are not fixed and may often be varied because of the personal beliefs of the individuals responsible for a particular formulation, or because of the cost of particular ingredients in a specific location. For example, as has been explained earlier in this manual, protein can be 'spared', sometimes by lipid and sometimes by carbohydrate so that lower dietary levels will promote adequate growth. Local conditions and preferences often dictate whether protein levels are in fact reduced for this purpose, by increasing levels of lipid, for example. Thus different farm-made or commercially available feeds for the same species may vary quite widely in analytical composition yet each satisfy the nutritional needs of the animal. The aim of successful formulation is to satisfy these needs in the most cost effective manner. Though nutritionally beneficial and cheaper in terms of ingredient cost than protein, high levels of lipid, for example, may make feed manufacture itself more difficult and costly. Final formulation is therefore a balance between known dietary requirements, ingredient availability and cost, manufacturing capability and expense, and the personal beliefs of the nutritionist responsible for the formulation.
Most is known about the nutritional requirements of trout and salmon and channel catfish because these species have been commercially grown intensively longer than others. A substantial amount of information is available about common carp and tilapia. Much less is known about the dietary requirements of shrimp and prawns or marine fish; still less is known about those for other species such as rabbitfish and Indian carps, though a number of test compounded feeds have been formulated.
'Optimum' levels of some dietary components are given in the sub-sections of the manual which follow but these must be used with caution. Optima vary according to so many other factors, including the environmental conditions, the species, the age of the animal, the types of raw material used, etc. It is impossible to give all the variants in a document of this size, so the reader is asked to consider the figures given as indicative rather than definitive. More details can be obtained by consulting the papers and books listed in 'further reading'.
The major dietary requirements of salmon and trout, which are similar, can be summarized as follows:
|
Lipid 1/
|
starter feeds (fry) |
15% |
|
grower feeds (fingerling) |
12% |
|
|
production feeds (older fish) |
9% |
|
|
Protein
|
starter feeds |
50% |
|
grower feeds |
40% |
|
|
production feeds |
35% |
|
|
Amino Acids |
lysine (fingerling feeds) 2/ |
5% |
|
methionine (fingerling feeds) 2/ |
4% (in absence of cystine) |
|
|
Available Phosphorus |
|
>0.8% |
|
DE |
|
2 800-3 300 kcal/kg |
|
Other Components |
|
see 'further reading' |
|
Essential Components: |
fish meal 3/; at least 1% inclusion of n-3 series fatty acids; natural or artificial carotenoids |
|
|
Negative Factors: |
non-protein nitrogen (e.g. urea); high carbohydrate levels (> 20%); high fibre levels (> 6%); rancid lipids. |
|
1/Commercial trout and salmon diets tend to have higher (up to 20%) lipid levels than those quoted here
2/As a % of protein.
3/Work on partial or complete replacement of this expensive ingredient is proceeding. Synthetic amino acids may be used to balance vegetable proteins.
Further reading for section 6.1:
Gaudet (1967); Phillips (1970); Nosho (1981); NRC (1973); NRC (1981); Kennedy (1978); EIFAC (1971); Edwards (1978); Halver (1972); Sedgwick (1982); Piper et al., (1982).
The nutrient requirements of channel catfish, like those of salmon and trout, have been the subject of much study in the U.S.A. because of the commercial importance of this species. They are summarized as follows:
|
Lipid
|
|
10% (experimental) |
|
fry to fingerlings |
35-40% |
|
|
fingerlings to sub-adults |
25-35% |
|
|
Protein |
adults and broodfish |
28-32% |
|
Carbohydrate |
higher levels tolerated than by salmon and trout |
|
|
Amino Acids
|
lysine |
5.1%) % of dietary |
|
methionine (cystine absent) |
2.3%) protein |
|
|
Available Phosphorus |
|
0.5% |
|
Salt |
|
0.5-1.0% |
|
DE |
|
2 700-3 100 kcal/kg |
|
Other Components |
|
see 'further reading' |
|
Essential Components |
not less than 7.5% fish meal (in intensive feeds; soybean is adequate substitute in feeds for extensive culture); not less than 14% animal protein. |
|
|
Negative Factors: |
rancid lipids; high fibre levels (>8-10%); more than 15% cottonseed meal. |
|
The specific nutritional requirements for other catfish species are little known. Diets for Siluris glanis developed in Hungary have been based on the requirements for channel catfish and an example is given in Appendix II.
Individual ingredients, such as boiled tilapia flesh, Moina spp., and fresh chub mackerel viscera, appear Co be good feeds for the fry of Clarias batrachus. Commercially produced pellets have given good results in Thailand in the pond culture of Clarias spp., compared to the traditional 9:1 trash fish:rice bran mixture. Compounded experimental diets for the fry of Clarias macrocephalus in Thailand were composed of fish meal, rice bran, fish oil, peanut meal and alpha starch, having approximately 10% lipid and 35.7% protein (on DM basis).
Further reading for section 6.2:
NRC (1983); Pillay (1967); ADCP (1983); ADCP (1980); Lee (1981); Tacon and Beveridge (1981); Taechajanta and Sitasit (1981); Srisuwantach et al., (1981); Dhamrongrat and Kasesunchi (1981); Halver (1982); Winfree (1979); Hastings (1973); Piper et al., (1982); Millikin (1982).
Of the carp species, most nutritional studies have been conducted on the omnivorous common carp. The known dietary requirements are summarized as follows:
|
Lipid |
|
up to 18% (higher levels spare protein) |
|
Protein |
|
25-38% |
|
Amino Acids
|
lysine |
5.7%)% of dietary |
|
methionine (cystine absent) |
3.1%) protein |
|
|
Available Phosphorus |
|
0.6-0.7% |
|
DE |
|
2 700-3 100 kcal/kg |
|
Other Components |
|
see 'further reading' |
|
Essential Components: |
at least 1% of each of n-3 and n-6 series fatty acids; high lipid diets for oogenisis in broodfish. |
|
|
Negative Factors: |
non-protein nitrogen: there is some evidence that carp may be able to utilize this (this is disputed, however); rancid fat; high lipid or carbohydrate after ovulation of broodfish. |
|
General specifications for warmwater omnivorous species were given by ADCP (1983) as follows:
|
|
fry & fingerlings |
juveniles & growers |
broodfish |
|
Lipid (min %) |
8 |
5 |
5 |
|
Protein (min %) |
30 |
25 |
30 |
|
Calcium (min/max %) |
0.8-1.5 |
0.5-1.8 |
0.8-1.5 |
|
Available Phosphorus (min/max %) |
0.6-1.0 |
0.5-1.0 |
0.6-1.0 |
|
Lysine (min., as % of protein) |
6.7 |
6.4 |
6.0 |
|
Methionine/Cystine (min as % of protein) |
4.0 |
3.6 |
3.3 |
|
DE (kcal/kg) |
3 100 |
2 800 |
2 800 |
Using these specifications, diets were formulated for various Indian carps (examples of these are given in Appendix II) and other species.
Further reading for section 6.3:
ADCP (1983); Viola and Arieli (1982); Szumiec (1977); Jauncey (1982); Millikin (1982); Pillay (1967); NRC (1983); Sen and Chatterjee (1979); Tacon (1986b).
Most tilapia of the genus Sarotherodon are omnivores, using plankton and detritus as feed, while those of the genus Tilapia utilize coarser food including large algae. The natural food preference of tilapia have been summarized by Jauncey and Ross (1982). A wide range of individual ingredients and simple mixtures of them have been used in the intensive culture of tilapias (Pullin and Lowe-McConnell, 1982), of which rice bran is a primary example. The following specification for compounded tilapia feeds are derived from Jauncey and Ross (1982):
|
Lipid |
10% |
(fry to 0.5g) |
|
8% |
(0.5-35 g animals) |
|
|
6% |
(35 g - market size) |
|
|
Protein
|
50% |
(fry to 0.5 g size) |
|
35% |
(0.5-35 g animals) |
|
|
30% |
(35 g - market size) |
|
|
Digestible Carbohydrate |
25% |
|
|
Fibre
|
8% |
(fry to 10g) |
|
8-10% |
(10 g - market size) |
|
|
Lysine |
4.1 |
as % of dietary protein |
|
DE |
2 500-3 400 kcal/kg |
|
|
Other Components |
see 'further reading' |
|
|
Essential Components: |
not less than 1% each of n-3 and n-6 series fatty acids |
|
|
Negative Factors: |
rancid fats |
|
Further reading for section 6.4:
Pullin and Lowe-McConnell (1982); Jauncey and Ross (1982); Viola and Arieli (1982); Hastings (1973).
Although the study of shrimp and prawn nutrition is much more recent than that of salmon and trout dietary requirements, knowledge of this topic is increasing rapidly due to the scale and value of shrimp farming world-wide. Dietary requirements appear to vary quite widely, particularly with respect to protein level, from species to species. In general, marine shrimp require high levels of animal protein (particularly marine), whereas freshwater prawns are more omnivorous. Provisional figures for some species are summarized below:
|
|
Penaeus |
Penaeus monodon |
Penaeus setiferus |
Macrobrachium rosenbergii |
|
Lipid % |
? |
2.5-10.0 |
3-8 |
2.5-6.0 |
|
Protein % |
48-60 |
35-39 |
20-32 |
20-25 |
|
Lysine 1/% |
9.2 |
? |
? |
? |
|
Methionine 1/% |
2.7 2/ |
? |
? |
? |
|
Other components: |
see 'further reading' | |||
|
Essential Components: |
1-2% n-3 series fatty acids, particularly HUFA members of the series; high n-3/n-6 fatty acid ratio; marine protein for marine shrimp particularly. | |||
|
Negative Factors: |
excessive cholesterol level; excessive vitamin C; Ca/P ratio >2.0 | |||
1/Based on the amino acid profile of mussel flesh (as % of protein).
2/Cystine present.
Further reading for section 6.5:
New (1976); New (1980); ADCP (1983); Meyers (1980); Abu Hassan (1984); Kanazawa (1984); Manik (1976); Manik et al., (1980); Yang (1979); Hastings (1975); Hew and Cuzon (1982); McVey (1983).
6.6.1 European Sea Bass, Sea Breams, Grouper and Yellowtail
6.6.2 Other Species
The nutritional requirements of the marine members of the super-family Percoidae are less well known than those of other cultured species. Existing knowledge has however, recently been reviewed (New, 1986a). The following is a summary of the requirements of that group of fish:
|
Component |
Species 1/ |
% |
Type of feed 2/ |
|
Lipid (% on DM) 3/
|
Grouper |
14 |
E |
|
Red sea bream |
6 |
C |
|
|
Yellowtail |
15-16 |
E |
|
|
Yellowtail |
6 |
C |
|
|
Gilthead sea bream |
8-9 |
E |
|
|
Gilthead sea bream |
9-11 |
C |
|
|
European sea bass |
12-13 |
E |
|
|
Protein (% on DM) 4/
|
European sea bass |
9-10 |
C |
|
Grouper |
40 |
E |
|
|
Red sea bream |
52-60 |
C |
|
|
Yellowtail |
53-57 |
E |
|
|
Yellowtail |
49-62 |
C |
|
|
Gilthead sea bream |
40-49 |
E |
|
|
Gilthead sea bream |
44-55 |
C |
|
|
Lysine (% of protein)
|
European sea bass |
40-53 |
E |
|
European sea bass |
50-69 |
C |
|
|
Gilthead sea bream |
5.0 |
|
|
|
Methionine (% of protein) |
Gilthead sea bream |
4.0 (Met + Cyst) |
|
|
Available |
|
not less than 0.7% as fed |
|
|
Phosphorous DE |
|
2 700-3 700 kcal/kg |
|
|
Other Components: |
see 'further reading' |
|
|
|
Essential Components: |
marine proteins; at least 1-2% of n-3 series fatty acids (of C20 and above); carotenoids for red sea bream. |
||
|
Negative Factors: |
as for salmon and trout. |
||
1/For scientific names, see Appendix XVII
2/E = Experimental diet; C = Commercial feed
3/Lipid levels of commercial diets for red sea bream and yellowtail are probably less than optimal 4/The higher levels of the range in each case are for fry feeds
|
Ayu: | ||
|
Lipid (% on DM) |
4-5) |
Commercial feeds |
|
Sea Bass (Lates calcarifer) and Snapper: | ||
|
Lipid (% on DM) |
13.9 |
Experimental feeds |
|
Rabbit Fish: | ||
|
Lipid (% on DM) |
12.5 |
Experimental feed |
|
Pacu and Tambaqui: | ||
|
Protein % |
30-33 (fingerlings) 25 (adults) |
Experimental feed |
General specifications for warmwater carnivorous species were given by ADCP (1983) as follows:
|
|
fry + fingerlings |
juveniles + growers |
broodfish |
|
Protein (min %) |
36 |
30 |
36 |
|
Calcium (min/max %) |
1.0-1.5 |
1.0-1.5 |
1.0-1.5 |
|
Available Phosphorus |
0.5-0.8 |
0.5-0.8 |
0.5-0.8 |
|
Lysine (min % of protein) |
5.6 |
5.3 |
5.0 |
|
Methionine + Cystine |
3.3 |
3.0 |
2.8 |
Further reading for section 6.6:
New (1986a); Kafuku and Ikenoue (1983); Millikin (1982); Meyers (1977); ADCP (1983); Kanazawa (1984).
