Effects of poultry by products meal protein substitution for fish meal protein on growth perform,ance, body composition and digestibility of juvenile black sea bass Centropristis striata
Presentation
Overview
Overview
Description
With the increasing cost and dwindling supply of fish meal, the need for a suitable and reliable alternative protein source has never been greater. Poultry by-product meal (PBM) is a low-cost, locally available feedstuff that has a high protein content and high quality amino acid profile. A previous study at UNCW (Sullivan 2008) demonstrated that diets with 60% of fish meal (FM) protein replaced with PBM protein had no significant effects on growth performance or survival of black sea bass (BSB) compared to menhaden FM based diets. Therefore, eight diets were formulated to replace FM protein with PBM protein at 0 (control), 40, 50, 60, 70, 80, 90, and 100%. All diets were formulated to have the same crude protein level (45%) and lipid level (14%). No additional protein sources, except wheat gluten as a binder, or attractants were used. All diets contained the same amount of vitamin and mineral premix. Menhaden fish oil and soybean lecithin were used as lipid sources. Diets were fed twice daily to triplicate groups of juvenile BSB (mean initial weight = 1.2 g) to apparent satiation for 8 weeks. Fish were held in 75-L rectangular tanks with 20 fish per tank supported by a recirculating seawater system. To measure apparent protein digestibility, chromic oxide (0.5%) was added to the diets following the feeding trial and fecal samples are being collected for analysis.
At the end of the feeding trial (56 d), final survival was 98% for all treatments, with no significant differences. Body weight gain (BWG) for fish fed the 40-90% protein replacement diets were not significantly different from the control diet. However, BWG for the group replacing 100% FM protein by PBM protein was significantly lower than the control group. BWG of the 90% protein replacement group was not significantly different from the 100% protein replacement group. Some fish fed diets with 100% protein replacement had cataract formation in their eyes. In addition to apparent protein digestibility, whole body and muscle and liver proximate composition (protein, lipid, ash, and moisture) are currently being studied. Based on growth data and survival, PBM protein can be substituted for FM protein at levels as high as 80% with no significant reduction of growth performance. The results indicated that PBM is a promising alternative protein substitute for FM protein for sustainable diet development in BSB.
