The Nutritive Value Of Corn Protein Concentrate As A Fish Meal Replacement In The Feeds Of Red Hybrid Tilapia, Oreochromis Sp.
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Date
2015-07
Authors
Leow, Tze Chin
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
The objective of this study is to evaluate the effect of fish meal (FM) replacement with corn protein concentrate (CPC) on growth performance and nutrient utilization of red hybrid tilapia, Oreochromis sp.. In the first experiment, five isonitrogenous (35% crude protein) and isolipidic (10% lipid) diets with five different inclusion levels of CPC at 0, 25, 50, 75 or 100% were formulated and fed to triplicate groups of tilapia (initial weight of 10.33 ± 0.02 g) twice daily for 63 days. Relatively high final body weight (FBW) (56.37 – 62.72 g) was obtained in treatments up to 50% CPC inclusion level. For CPC75 and CPC100, final body weight (FBW) (45.68 and 16.8 g respectively) were significantly (P<0.05) reduced. With the exception of CPC100 diet, there were no significant differences (P>0.05) in feed conversion ratio (FCR) and feed intake (FI) among all the treatments. For the whole body composition, there was a gradual decreasing trend shown in crude protein level with increasing CPC inclusion levels. Lipid content in whole body was not significantly different. Apparent digestibility coefficient of protein (ADCP) was gradually increasing from 80.63 to 84.65% in the treatments up to 75% CPC inclusion level. However, ADCP at CPC100 was significantly reduced to 73.65%. For skin and muscle coloration, there was significantly higher colouration in terms of b-values shown on the 100% CPC fed fish (7.89 and 3.66 respectively) as compared to other treatments. The total carotenoid content in muscle was significantly the lowest and highest in fish fed the control (0.0162 mg/kg) and CPC100 (0.0353 mg/kg)diet, respectively. In the second experiment, seven isonitrogeneous (35% crude protein) and isolipidic (10%) with CPC inclusion diets were alternatively mixed with 25% of soy protein concentrate (SPC) to improve overall nutrient plant protein quality; and supplemented alternatively with 0.5% betaine-HCl and 2% dried basil leaves (DBL) as feeding attractants (FA) to enhance the palatability and FI of the red hybrid tilapia. The tilapia were tested in triplicate groups (initial weight of 7.30 ± 0.02 g) and fed twice daily for 56 days. Diets with 25% of SPC tended to enhance the growth performance and feed utilization efficiency of tilapia compared to fish fed the solely added CPC diet at the same percentage of plant protein ingredients (PPI) in the diet. Tilapia fed with diets C-SPC50 and C-SPC50A (75% PPI added) were shown better % weight gain (WG) at 528.91% and 594.89%, respectively, as compared to WG of tilapia fed with CPC75 (263.82%). Similar outcomes also can be proved at the diets among CPC100, C-SPC75 and C-SPC75A. Addition of both FA into the diets showed better specific growth rate (SGR), WG, FCR and FI as compared to the diets without supplementation of feeding attractants. With the exception of CPC100, no significant differences found on whole body protein and whole body lipid among all the treatments. In both experiments, no histological changes were observed in the gut of the red hybrid tilapia fed with CPC. In conclusion, the results showed that CPC can be a potential alternative PPI to replace FM up to 50% in tilapia diet without negatively affect growth performance and nutrient utilization. However, to replace FM with more PPI, 25% of SPC with supplementation of 0.5% betaine-HCl and 2% of DBL can be mixed into 50% of CPC diets to make the substitution level up to 75% in tilapia diet without causing any adverse effect.
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Keywords
Nutrient utilization of red hybrid tilapia