Vol. 14,No. 4, October 2015
Effect of reducing 3.2% dietary protein level on the growth performance and immunity of Nile tilapia (Oreochromis niloticus) with supplementation of multi amino acids
Description:1-Animal Science College, South China Agricultural University, Guangzhou, China;2-Key Laboratory for Aquatic Products Safety of Ministry of Education/State Key Laboratory of Biocontrol, The school of Life Sciences, Sun Yat-sen University, Guangzhou, China. a Li-Liu Zhou, Xue-Ming Dan and Yan-Wei Li contributed equally to this paper *Corresponding author’s email: ganlian@scau.edu.cn
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Abstract
Reducing dietary protein content in fish feeds will reduce cost of production if growth performance can be maintained. In this study, we assessed the effects of reduced dietary protein content from 33.5% to 27.4% with ideal amino acids profile on the growth, immune parameters, intestinal microvilli length and total ammonia nitrogen discharge of tilapia. After 8 weeks of feeding, growth performance and feed efficiency were not affected by reducing dietary protein content from 33.5% to 30.3%, while fish fed 27.4% CP had the lowest weight gain. Total ammonia nitrogen discharged into the water 9 hours after the feeding was decreased by about 35%. Serum lysozyme activity, blood respiratory burst activity and serum ACH50 were not significantly affected by dietary protein content. Fold height, enterocyte height and microvillus height of proximal and middle intestine were significantly increased with reducing of dietary protein. Results indicated that 3.2% dietary protein content can be reduced, which had no effects on growth performance and immunity of Nile tilapia in practical diet.

Keywords: Tilapia, Ideal amino acids profile, Dietary protein, Growth
Author:Zhou L.L.1,a; Dan X.M.1,a; Li Y.W.2,a; Li X.X. 1; Chen X.L.1; Li Y.1; Gan L.1*
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