Table 1. Ingredients (g per Kg), proximate composition on a dry weight basis (%) and δ15N values of four experimental diets containing different levels of substitution of fishmeal with poultry by-products meal (PBM; 0, 33, 67 and 100% replacement).
| TREATMENTS | ||||
| Ingredients | 0PBM | 33PBM | 67PBM | 100PBM |
| Poultry by-product meal (PBM)1 | 0.0 (0.0) | 235 (0.3) | 440 (0.6) | 590 (0.9) |
| Fishmeal2 | 660 (0.9) | 400 (0.5) | 175 (0.2) | 0 (0.0) |
| Corn meal | 55 (0.01) | 55 (0.01) | 55 (0.01) | 55 (0.01) |
| Poultry oil3 | 0.0 | 5.0 | 17 | 35 |
| Fish oil4 | 72 | 52 | 28 | 0 |
| Corn starch | 91 | 131 | 166 | 201 |
| Gelatin | 60 (0.1) | 60 (0.1) | 60 (0.1) | 60 (0.1) |
| Rovimix for carnivores fish5 | 30 | 30 | 30 | 30 |
| Stay c5 | 4 | 4 | 4 | 4 |
| Sodium Benzoate | 2.3 | 2.3 | 2.3 | 2.3 |
| Choline chloride | 0.9 | 0.9 | 0.9 | 0.9 |
| Tocopherol | 0.1 | 0.1 | 0.1 | 0.1 |
| Cellulose | 25 | 25 | 25 | 25 |
| TOTAL | 1000 | 1000 | 1000 | 1000 |
| Proximate composition (% of dry matter) | ||||
| Crude protein (%) | 43.1 | 43.4 | 43.7 | 43.6 |
| Crude fat (%) | 12.5 | 12.5 | 12.5 | 12.3 |
| Ash (%) | 19.8 | 15.1 | 12.1 | 8.8 |
| NFE6 | 24.5 | 29.0 | 31.7 | 35.3 |
| Diet isotopic composition | ||||
| δ15N (‰) | 12.7 | 9.0 | 6.1 | 4.2 |
The four diets were fed to juvenile rainbow trout (Oncorhynchus mykiss) for 80 d. Fractional N contribution is expressed inside parentheses ( ).
1
“Pet food grade” (69.6% crude protein, 12% crude lipid) supplied by the National Renderers Association, USA.
2
Tuna fishmeal (60.0% crude protein, 6.9% crude lipid) from Proteínas Marinas y Agropecuarias, Guadalajara, México.
3
Poultry oil from Proteínas Marinas y Agropecuarias, Guadalajara, México.
4
Sardine oil.
5
Rovimix; Stay–C donated by DSM, Guadalajara, México.
6
Nitrogen free extract: calculated by difference: NFE = 100-CP-CF-Ash.
δ15N values of main nitrogen-containing ingredients: Fishmeal (14.1‰), poultry by-product meal (3.4‰) and gelatin (7.8‰).