68 Safina Musa, Christopher Mulanda Aura and Rodrick Kundu
Based on the diet administration, each diet was divided into 3 different
treatments (100, 70, 50%) except diet CP25CL8 which was divided into only
two treatments (100 and 70%). All the treatments were in 3 replicates and
satiation feeding was considered at 100%. The experimented lasted for 4
months.
At the end of the experiment, all the fish were counted, weighed and
length taken for determination of weight gain, specific growth rate, feed
efficiency, protein efficiency ratio, feed intake, protein intake and survival.
Blood samples were collected from 3 fish in each hapa 24 h after last
feeding at 3rd and 4th month. Fish were anaesthized using tricaine methane
sulphonate (MS-222). Blood samples were then collected from the caudal vein
of the fish using heparinized syringes when the fish were completely sedated.
Blood samples were centrifuged at 8000 rmp for 5 minutes using Mikro 120,
Hettick Zentrifugen, Germany immediately after collection. Blood plasma was
separated and stored at 4^0 C in a refrigerator.
Triglyceride, cholesterol and total protein were analysed after but for
glucose, it was analysed within 18 h after blood collection. Triglyceride,
cholesterol and glucose were analysed by triglyceride, cholesterol and glucose
kits, respectively with the help of manufacturer’s instructions (Human
Gesellschaft fur Biochemica und Diagnostica mbH, Germany). Total protein
was analysed with total protein reagent (Tonyar Biotech Inc., Taiwan) with
Lympho Chek Assayed Control standard solution (BioRad Laboratories,
USA). The blood parameters (triglyceride, cholesterol, glucose and total
protein) were measured by spectrophotometer (Clinical Analyzer model 1011).
For the last blood sampling, at the end of the experiment, the fish were
sacrificed and dissected to weigh the viscera, liver and intraperitoneal fat in
order to determine hepatosomatic index (HIS), Viscerasomatic index (VSI)
and intraperitoneal fat index (IPF). The lengths of the intestines were also
measured to determine intestinal length ratio.
Proximate composition of the feeds were determined using the standard
methods of Association of Official Analytical Chemist (AOAC, 1995). Crude
protein was determined by use of micro-kjedahl method, crude fat was
extracted by soxhlet method, ash by incineration of samples in muffle furnace
at 550^0 C for 6 h and moisture was calculated from the weight difference after
oven drying the samples at 1050 C for 24 h.
The following formulae were used for calculations:
Percentage weight gain (WG %) = 100 x (final mean weight-initial
mean weight)/initial mean weight.