Prof: Le Thanh Hung
Faculty of Fisheries
Nong Lam University – Ho Chi Minh City – Vietnam. – lthungts@yahoo.com.vn
A study using the SSE product in tilapia feed was carried out in 15 500-L composite tanks. Five diets, containing fishmeal, soybean meal, rice bran, cassava meal, fish oil and premix were formulated to contain 32% crude protein and 6% lipid. Diet 1, the control, included 5% fish-meal in its composition. Diet 2 was free of fishmeal. Diet 3 had no fishmeal but was supplemented with 2% SSE top dressing after pelleting. Diet 4 was free of fishmeal and mixed with 1% SSE. Diet 5 was likewise free of fishmeal but was mixed with 2% SSE. The formulations of the five diets are presented in Table 1. Tilapia fingerlings weighing 10 g each were fed the five diets. The fish were stocked at a density of 30/tank and fed three replicates for each diet for eight weeks.
Summary:
As shown in Table 2, fish that received Diet 2 had the lowest growth rate and the highest feed-conversion ratio FCR. The treatments comprising of a mixture of SSE in the pelleted diet or spraying SSE as a top dressing at 2% dosage exhibited the same growth performance and FCRs as those in the 5%-fishmeal diet treatment. The survival rates were lowest using the fishmeal- free Diet 2 and highest with Diet 5. Thus it was observed that mixing 2% SSE in tilapia feed improved survival rates, indicating that the SSE product helped to reduce fishmeal in the diet without affecting growth and feed utilization. Therefore adding the SSE product in the pelleting process could help reduce feed costs to approximately U.S. $15/mt. Other studies to evaluate SSE use in shrimp feed are ongoing.
