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Growth and nutrient utilization of Murray cod Maccullochella peelii peelii (Mitchell) fingerlings fed diets with varying levels of soybean meal and blood meal
Author(s) -
Abery Nigel W,
Gunasekera Rasanthi M,
De Silva Sena S
Publication year - 2002
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1046/j.1355-557x.2002.00672.x
Subject(s) - biology , soybean meal , fish meal , zoology , meal , juvenile , dry matter , blood meal , feed conversion ratio , aquaculture , nutrient , fishery , food science , fish <actinopterygii> , body weight , ecology , endocrinology , raw material
The Australian native freshwater fish Murray cod, Maccullochella peelii pellii (Mitchell), currently supports a fledgling inland aquaculture industry, which is thought to have considerable growth potential. The aim of this study was to evaluate the suitability of two alternate protein sources [blood meal (BM) and defatted soybean meal (SBM)] as substitutes for fish meal at various levels of inclusion in diets for juvenile Murray cod. The growth performance of juvenile Murray cod in response to nine isonitrogenous and isocalorific diets (50% protein, 14% lipid, 20.2 kJ g −1 ) consisting of a control diet in which protein was supplied from fish meal, and test diets in which the fish meal protein was substituted at levels of 8%, 16%, 24%, and 32% with BM or SBM was evaluated from a 70‐day growth experiment. The per cent apparent dry matter (% ADC dm ) and percentage protein digestibility (% ADC p ) of the test diets were also determined using Cr 2 O 3 as a marker. Survival in all the SBM dietary treatments was high but that of fish on the BM dietary treatments was significantly ( P < 0.05) lower than in all the other dietary treatments. Specific growth rate (% day −1 ) of Murray cod fed SBM incorporated diets ranged from 1.63 ± 0.06 to 1.78 ± 0.10 and even at the highest level tested (32% of the dietary protein from SBM) was not significantly different ( P > 0.05) from the fish fed the control diet (1.65 ± 0.09). Feed conversion ratios of the SBM dietary treatments ranged from 1.36 ± 0.08 to 1.45 ± 0.07. The protein efficiency ratios and protein conversion efficiencies of Murray cod in the soybean meal treatments were also good and for a majority of the SBM diets were better than those for the control diet. Per cent ADC dm and ADC p of the SBM diets tested ranged from 70.6 ± 1.46 to 72.3 ± 1.81% and 88.6 ± 0.57 to 90.3 ± 0.17%, respectively, and was not significantly different ( P > 0.05) from the control diet (% ADC dm 74.3 ± 1.63; % ADC p 91.3 ± 0.55). The reasons for significantly poor survival and growth of Murray cod reared on BM incorporated diets, and relatively poor digestibility of these diets are discussed. The study shows that for Murray cod diets in which fish meal protein is substituted up to 32% performance or carcass composition is not compromised.