| Popis: |
The use of poultry by-product meal-pet food grade (PBM-PFG, 66% crude protein) as a substitute for a fish meal blend (FM, a 50/50 mix of American menhaden meal and Mexican sardine meal, 65% average crude protein), in a control diet containing 35% crude protein, was evaluated in Pacific white shrimp. The replacement levels (w/w) were: 35, 50, 65 and 80%, with 13.7, 19.6, 25.5 and 31.4% PBM-PFG inclusion in the test diets, respectively. Two commercial feeds from Mexico, containing 30 and 35% protein, were used as additional controls. The diets were fed to shrimp (450 mg initial weight) in a 4 week feeding trial in order to evaluate growth, feed consumption, feed conversion ratio (FCR), total biomass, survival, protein efficiency ratio (PER) and nitrogen retention efficiency (NRE). In addition, apparent protein, dry matter and energy digestibility coefficients (PDC, DMDC, EDC) of all diets, as well as those of the ingredients, FM and PBM, were determined using the in vivo chromic oxide method and shrimp of 1.6 to 2 g initial weight. Digestibility coefficients were similar and greater than 80% for all diets. PDC, DMDC and EDC were high and similar for FM and PBM-PFG. Survival along the growth trial, FCR, PER and NRE were not affected by any of the test diets, but there was a slight linear negative effect of replacement level on consumption and growth, which seemed related to energy over formulation rather than a palatability problem. The commercial control diets, which did not contain PBM-PFG, gave results for growth that were equal to or lower than those of the test diets. Results of this experiment showed that PBM-PFG can adequately replace w/w up to 80% of FM in commercial diets for the white shrimp L. vannamei. |
Full Text from ScienceDirect