Open AccessEffects of Feeding Levels on Growth Performance, Feed Utilization, Body Composition, and Apparent Digestibility Coefficients of Nutrients for Grouper Epinephelus coioides Juveniles
Author(s) -
Luo Zhi,
Liu YongJian,
Mai KangSen,
Tian LiXia,
Tan XiaoYing,
Shi JinFang
Publication year - 2006
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.2006.00004.x
Subject(s) - grouper , biology , epinephelus , zoology , feed conversion ratio , composition (language) , weight gain , dry matter , body weight , nutrient , juvenile , growth rate , fishery , endocrinology , fish <actinopterygii> , ecology , linguistics , philosophy , geometry , mathematics
An experiment was conducted to determine effects of feeding levels on growth performance, feed utilization, body composition, and apparent digestibility coefficients (ADCs) of nutrients for juvenile grouper Epinephelus coioides (initial weight, 10.31 ± 0.36 g). Grouper were fed a practical diet from 0 (starvation) to 3.5% (at 0.5% increments) body weight per day (bw/d) for 8 wk. ANOVA indicated that growth performance, feed utilization, body composition, and ADCs of dry matter, protein, and energy were significantly ( P < 0.05) affected by feeding levels. Survival was the lowest for the starvation group and for fish fed a ration of 0.5% bw/d. Final mean body weight, weight gain (WG), specific growth rate, and metabolic growth rate increased with feeding rate from 0 to 2.5% bw/d ( P < 0.05) and showed no significant differences above the level ( P > 0.05). Feed conversion rate was significantly lower at a feeding level of 2.0% bw/d than above and below the level ( P < 0.05). Protein efficiency ratio was markedly highest at the 2.0% bw/d ration level ( P < 0.05). Lipid contents of whole body, muscle, and liver increased with increasing feeding rates from 0 to 3% bw/d and showed a slight decline at the feeding level of 3.5% bw/d. Protein contents of whole‐body composition, muscle, and liver remained relatively stable with the different ration amount with the exception of fish fed a ration of 0.5% bw/d, at which grouper possessed significantly lower body protein concentration ( P < 0.05). Condition factor, viscerosomatic index, and hepatosomatic index were the lowest for fish fed 0.5% bw/d and tended to increase with the increasing feeding levels. ADCs of dry matter, protein, and energy decreased with increasing feeding levels from 0 to 2.5% bw/d and then remained relatively constant over the level. Based on the broken‐line regression analysis using WG data, the optimum and maintenance feeding levels for grouper were 2.5% bw/d and 0.25% bw/d, respectively.