Système d’information sur les ressources alimentaires et d’engrais en aquaculture
 

Frequently asked questions (FAQs)

1. What is a typical, suitable proximate composition for the diet of European seabass?

 

Proximate composition (% dry feed basis) Life stage/size class
Fry Fingerling Juvenile Grower Broodstock
Crude protein, % min 50 45–50 45-50 45 45
Crude lipid, % min 15-18
Crude fibre, % max 2 3–4 3–4 3–4 3–4
Digestible energy, min kJ/g   19 19 19 19
Protein to energy ratio, mg/kJ   25 25 25 25
Phosphorous, % min 0.8 0.8 0.8 0.8 0.8
2. What protein level and essential amino acid levels are required for European seabass diets?

Dietary protein requirement of European seabass varies at different stages of its life and they require 10 essential amino acids like any other fish species for normal growth.

Nutrient level Life stage
Fry Fingerling Juvenile Grower Broodstock
Crude protein, % min 50 45–50 45-50 45 45
Amino acids (% minimum of dietary protein)
Arginine   3.9–4.6 4.6 4.6 4.6
Histidine     1.6 1.6 1.6
Isoleucine     2.6 2.6 2.6
Leucine     4.3 4.3 4.3
Lysine   4.8 4.8 4.8 4.8
Methionine     2.3 2.3 2.3
Methionine + Cystine   4      
Phenylalanine     2.6 2.6 2.6
Threonine   2.6 2.7 2.7 2.7
Tryptophan   0.5–0.7 0.6 0.6 0.6
Valine     2.9 2.9 2.9
3. What protein sources could be used in European seabass feeds and their proximate composition?
  Crude protein Crude lipid Ash Phosphorus
Marine sources        
Fishmeal 70.0  8–10  10–12 2.1
Krill meal 58.0 18.0 13.0  
Cereals        
Corn 8.0  1–3  1–2 0.3
Corn gluten meal 60.0 3.0 2.0 0.4
Wheat 12.0  1–3 17.0 0.1
Wheat gluten 78.0 2.0 0.8 0.1
Pulses        
Pea 22.0  1–2 3.0 0.4
Faba bean 24.0 2.0 3.0 0.5
Lupins 34.0 8.0 3.0 0.4
Oilseeds        
Rapeseed meal  38–44  1–2  3–7 1.0
Sunflower meal 35.0 4.0 8.0 0.9
Full fat soybean 36.0 19.0 6.0 0.5
Soybean meal 46–48  0,5–1 6.0 0.7
Soy protein concentrate 68.0 1.5 4.0 0.9
4. What lipid sources could be used in European seabass feeds and what is their fatty acid composition?

Marine fish oil such as menhaden, herring, mackerel, capelin, salmon, sardine and anchovy and plant oil such as palm, soya, olive and linseed are commonly used in seabass feed. Fatty acid profiles (EPA and DHA) of marine fish oils are given below:

Fatty acid Menhaden Herring Mackerel Capelin Salmon Sardine Anchovy
20:5n-3 (EPA) 13 2.9 7.6 9.4 9.8 16.9 18.2
22:6n-3 (DHA) 8.2 2.7 7.7 2.7 10.4 12.9 10.9
EPA + DHA 21.2 5.6 15.3 12.1 13.2 29.8 29.1

EPA = eicasopentanoic acid; DHA= docosahexanoic acid

5. What alternative ingredients could be used in order to decrease fishmeal dependence in European seabass diets?

The following table provides a list of possible ingredients and chemical composition of practical diets developed to decrease fishmeal use in European seabass formulations:

Ingredients (% dry matter basis) diet 1 diet 2 diet 3 diet 4 diet 5
Fishmeal (crude protein, 70%) 52.0 40.0 25.0 12.5 5.0
Corn gluten meal   8.0 20.6 21.0 20.0
Wheat gluten     5.0 16.6 23.8
Extruded wheat 19.5 6.8 2.0    
Soybean meal (crude protein, 48%) 9.5 15.0 15.0 14.0 13.2
Rapeseed meal   10.0 10.0 10.0 10.0
L-Lysine     0.07 0.65 1.00
CaHPO4.2H20 (18% phosphorus)     0.67 2.25 3.28
Fish oil (Scandinavian) 15.9 17.1 18.6 19.9 20.7
Binder 1.0 1.0 1.0 1.0 1.0
Yttrium oxide 0.1 0.1 0.1 0.1 0.1
Mineral premix 1.0 1.0 1.0 1.0 1.0
Vitamin premix 1.0 1.0 1.0 1.0 1.0
Chemical composition (% dry matter basis)
Dry matter 90.3 89.7 89.6 89.4 89.0
Crude protein 45.0 48.3 50.4 46.9 50.7
Crude lipid 21.6 21.7 20.0 22.8 18.3
Phosphorus 1.2 1.2 0.9 0.7 0.6
Gross energy, MJ/kg 24.2 24.3 24.1 24.8 24.4
6. What alternative ingredients could be used in order to decrease fish oil dependence in European seabass diets?

The following table provides a list of possible ingredients and chemical composition of practical diets developed to decrease fish oil use in European seabass formulations:

Ingredients (% dry matter basis)  Diet A    Diet B    Diet C  
Fishmeal (Scandinavian, low temperature)  40.0    40.0    40.0  
Corn gluten meal  26.3    26.3    26.3  
Wheat  15.2  15.2    15.2  
Premixes  2.5    2.5    2.5  
Anchovy oil  16.0    6.4    6.4  
Rapeseed oil  0   1.6    3.8  
Linseed oil  0   5.6    3.8  
Palm oil  0   2.4    1.9  
 Proximate composition  (% dry matter basis) 
Dry matter  89.8    89.1    90.6  
Crude protein  53.2    51.8    52.8  
Crude fat  22.2    20.8    25.8  
Carbohydrates  17.1    20.3    14.6  
Ash  7.5    7.1    6.8  
7. What could be a typical practical diet formulation for larval rearing in European seabass culture?
Ingredients Diet 1 Diet 2
Fishmeal   55
Fish protein hydrolysate 4 11
Casein 4  
Squid meal 14  
Mussel meal 4  
Crayfish meal 14  
Fish roe 19  
Egg yolk 14  
Lactic yeast 4  
Fish oil 5 9
Soy oil    
Soy Lecithin 3 7
Marine lecithin    
Starch   5
Dextrin    
Vitamin mixture 5 8
Mineral mixture 4 1
Betaine   1
Zein 6  
8. What is the most appropriate feeding schedule for European seabass at different stages of the life cycle?

Larval feeds are distributed using belt feeders or other specially developed feed dispensers. In cage culture operations, both hand feeding based on feeding tables provided by feed manufacturers and the use of mechanical feed distributors occurs. Commercial cage farms use hand feeding as well as automatic feeders combined with video monitoring of feeding behaviour.

Body weight (g) Pellet size (mm) 13 °C 15 °C 17 °C 19 °C 21 °C 23 °C 25 °C 27 °C 29 °C
0.3–0.5  0.5         Ad-libitum         
0.5–1.0  0.8         Ad-libitum         
1.0–3  1.1  1.21   2.42   3.63   4.84   5.41   5.81   5.85   5.24   3.52 
3–8  1.5  0.91   1.83   2.74   3.66   4.09   4.39   4.42   3.95   2.66 
8–15  1.9  0.74   1.48   2.22   2.96   3.31   3.55   3.58   3.20   2.15 
15–20  1.9  0.63   1.27   1.90   2.53   2.83   3.04   3.06   2.74   1.84 
20–40  3  0.52   1.03   1.55   2.07   2.31   2.48   2.50   2.24   1.50 
40–60  3  0.43   0.86   1.29   1.72   1.93   2.07   2.08   1.87   1.25 
60–100  4.5  0.35   0.71   1.06   1.41   1.58   1.69   1.70   1.53   1.02 
100–160  4.5  0.29   0.57   0.86   1.14   1.28   1.37   1.38   1.24   0.83 
160–300  4.5  0.23   0.46   0.69   0.91   1.02   1.10   1.11   0.99   0.66 
300–450  6.5  0.16   0.33   0.49   0.66   0.74   0.79   0.80   0.71   0.48 
450–700  6.5  0.13   0.26   0.40   0.53   0.59   0.63   0.64   0.57   0.38 
7001 200  9  0.10   0.20   0.29   0.39   0.44   0.47   0.47   0.42   0.28