Fishmeal replacement with feather-enzymatic hydrolyzates co-extruded with soya-bean meal in practical diets for the Pacific white shrimp (Litopenaeusvannamei)

A feeding experiment was conducted to examine the potential of a commercial steam-processed-feather meal (SPFM) and feathers enzymatically hydrolysed for 60 or 120 min (EHF60 and EHF120) as substitutes for fishmeal (FM) in di ets for white shrimp juveniles. Enzymatically hydrolised feathers or SPFM w ere blended through an extruder with soyabean meal (SBM) in a 1:1 ratio (EH F-SBM, SPFM-SBM). Isoproteic and isolipidic diets were formulated to contai n 9% EHF60-SBM, 9% EHF120-SBM and 18% EHF60-SBM. These diets were compared with a diet containing 13.7% SPFM-SBM and a control diet designed to contai n 18.4% FM and no feather. Quadruplicate groups of 15 shrimp (0.33 g initia l-body weight) were fed twice a day on each diet for 4 weeks. The weight ga in of shrimp fed on the three EHF-SBM diets did not differ from that of shr imp fed on the FM-control diet, however, shrimp fed on the SPFM-SBM diet ga ined less weight. The EHF60 and EHF120 coextruded with SBM in a 2:1 ratio w ere evaluated in a commercial rearing pond. Both ingredients included at 20 % in the test diets were compared with a control diet containing 17.8% FM. Triplicate groups of juvenile shrimp (3.4 g initial-mean weight), randomly allocated in I m(3) plastic cages, were fed with the test diets during 30 d ays. Growth (weight gain, specific-growth rate (SGR)) and nutritional value of the diets, food conversion ratio (FCR), protein-efficiency ratio (PER), digestibility were similar. In summary, these results indicate that white shrimp can be fed with a practical diet containing 20% EHF-SBM (2:1) withou t impairing growth or food conversion. The use of 20% EHF-SBM (2:1) allowed the fish-meal portion to be reduced by nearly by 55%.