EFFECT OF USING POULTRY BY-PRODUCT MEAL ON AQUATIC PELLETS QUALITY AND FISH GROWTH USING RING-DIE PELLETING MACHINE

Abstract

In present study, three feed blends containing 30% protein with an energy content of 350 Kcal/100 grams were formulated with three levels of poultry by-product meal (PBM) of 0.0, 50 and 100% as a cheaper protein source instead of Herring fish meal (HFM) along with appropriate levels of soybean meal, corn flour, vitamin mix and mineral mix and pelleted in a ring-die pelleting machine to fed Nile tilapia fingerlings (5.4 ± 0.13 g).The ring-die pelleting machine was evaluated under three levels of replacement percentage of PBM in feed formula, roller clearances (0, 2 and 4mm) and levels of moisture content of (15, 20 and 25%). The evaluation included machine production rate, pelleting efficiency, specific energy consumption, pellets quality (durability, bulk density) and economical costs of aquatic feed pellets mass, in addition to growth performance of fish. The obtained data showed that, the highest values of machine productivity of 58.68 kg/h, pelleting efficiency of 95.48%, lowest specific energy consumption of 29.65 kW.h/Mg and the lowest cost per mass unit of 1976.68 L.E/Mg were recorded in the case of PBM percentage of 100% ,roller clearance of 0 mm and moisture content of 15%, while the highest values of durability(0.914 g/cm3) and pellets bulk density (92.54% )were recorded at roller clearance of 2 mm, PBM percentage of 100% and moisture content of 15%.The results revealed that no disparity in growth response of fish and efficiency of feed utilization and did not affect fish composition of dry matter, protein, or fat levels in addition to the survival rate of Nile tilapia was high in all treatments. Hence, HFM can be replaced by PBM as a cheap source of protein in Nile tilapia diets because no significant effect for both HFM and PBM on pellet quality, machine performance and fish growth