EFFECT OF TOTAL REPLACEMENT OF FISHMEAL BY DIFFERENT SOYBEAN MEAL, DRIED AMINO YEAST AND GREEN SEAWEEDS (Ulva SP.) COMBINATIONS IN RED TILAPIA (Oreochromis niloticus ♀ × O. aureus ♂) FRY DIETS ON GROWTH PERFORMANCE AND FEED EFFICIENCY
Talaat N. Amer
Department of Fish Nutrition, Central Laboratory for Aquaculture Research, Agriculture Research Center, Egypt.
E-mail: [email protected]
Received 17/ 1/ 2012
Accepted 20/ 2/ 2012
Abstract
This study was conducted to determine if soybeen meal (SBM) in combination with dried amino yeast (AY) or/and a local seaweed (Ulva Sp.) (SW) can replace fishmeal (FM) in the diets of red tilapia (Oreochromis niloticus × O. aureus) (0.61 ± 0.01g initial body weight). Five isonitrogenous and isocaloric diets were formulated to provide 24% protein and 435 kcal/100 g diet. T1 (FM-based) diet was formulated to serve as the control. T2 (SBM-based diet) served as a secondary control. The other three diets were: T3 (SBM-based + 1% AY), T4 (SBM-based + 10% SW) and T5 (SBM-based + 1% AY+ 10% SW). Each diet was used to feed triplicate groups of fish two times a day
to satiation for 9 weeks. The highest mean final body weight (FBW) (6.68 g fish-1) and the lowest FBW (4.39 g fish-1) were recorded with T1 and T5, respectively. The same trend was observed with all other growth performance parameters. The best survival rate (83.33 %) was observed with T1 while the worst survival rate (70.00%) was found with T2 and T4. The best feed conversion value (FCR) was recorded as 1.36 with T4 and the poorest FCR value was determined as 2.02 with T5. The highest protein productive value (PPV %) (52.16 %) was noticed when fish were maintained at T1, followed by T3 and T4, while the lowest PPV (36.09%) was found with T5. The same trend was noticed with all other nutrient utilization parameters. The higher values of body protein content were found with T1 and T5 while the lower values appeared with T2, T3 and T4. The highest significantly (P < 0.05) body lipid content was found with T2, while the lower values were observed with T1, T4 and T5. The results obtained in this study suggest that the inclusion of 1% dried amino yeast or 10% green seaweeds (Ulva sp.), but not together in all plant-based diets for red tilapia fry improved growth performance and sharply reduced the feed cost without any negative consequences on nutrient utilization or body composition.
Keywords: Red tilapia, fishmeal, soybean meal, amino yeast, seaweeds, Ulva sp., growth performance, feed utilization.
