Effects of protein
restriction with subsequent realimentation on growth performance of juvenile
Chinese shrimp (Fenneropenaeus chinensis)
Lixin Wu, Shuanglin Dong-2002
Aquaculture, 210(1-4): 343-358
Abstract:
The effects of protein restriction in the diet with
subsequent realimentation on growth responses of juvenile Chinese shrimp, Fenneropenaeus
chinensis (initial mean wet weight 1.347 g), were investigated. The
control group (Group C) was fed an adequate diet containing 44.6% crude
protein and 18.5 kJ gross energy/g dry matter throughout the experiment. For
treatment Groups T15 and T30, in the restriction phase
(weeks 1-2) dietary crude protein contents were reduced to 15.0% and 29.3%,
respectively, with constant energy supply, while in the realimentation phase
(weeks 3-6) they were supplied with the same diet as the control group.
Protein restriction led to significant decrease in specific growth rates and
body weight of shrimp. However, when the shrimp were transferred from
protein restriction to realimentation, they had significantly increased
specific growth rates in terms of dry matter, protein and energy (SGRd,
SGRp and SGRe) compared with the control shrimp. At
the end of the experiment, the shrimp in Group T30 achieved
complete growth compensation, while those in Group T15 were still
significantly smaller than the controls. As dietary protein levels reduced,
feed conversion efficiencies and apparent protein digestibility decreased,
but feed intake and protein efficiency ratio increased. The shrimp responded
to a change from protein restriction to realimentation by displaying
improved feed conversion efficiencies (FCEd, FCEp and
FCEe) compared with the controls, although those in Group T15
delayed in showing the enhanced FCE values. In the initial 2-week
realimentation, the shrimp in Group T15 showed significantly
higher feed intake, and lower apparent digestibility of dry matter and
protein than those of the controls. There was no significant difference in
protein efficiency ratio among all groups in the realimentation phase. The
above results suggest that compensatory growth in Group T30 is
mainly dependent on improved feed conversion efficiencies, while that in
Group T15 is attributable to both improved feed conversion
efficiencies and increasing feed intake. After 2-week restriction, the
shrimp showed lower body crude protein, lipid and energy content, and higher
moisture and ash content than the controls. However, during the course of
realimentation, the differences between the previously protein restricted
shrimp and the controls diminished. This indicates that compensatory growth
after a period of protein restriction in juvenile Chinese shrimp was
accompanied by a complete recovery in body composition and energy content.
(Aquaculture Research Laboratory, Fisheries College,
Ocean University of Qingdao, Qingdao, 266003, People's Republic of China,
Tel.: +86-532-2032964; fax: +86-532-2894024, e-mail: dongsl@mail.ouqd.edu.cn)