Effects of Dietary Protein Levels on Haemato-biochemical Response and DNA: RNA ratio of Pabda, Ompok bimaculatus (Bloch, 1794)

Abstract

Five iso-energetic semi-purified diets with varying
levels of crude protein viz., P25 (25.10%), P30
(29.93%), P35 (35.28%), P40 (39.73%) and P45
(44.49%) were fed to Pabda, Ompok bimaculatus
fingerlings (average weight 3.29±0.01 g) in triplicate
groups (11 healthy fish per replicate) for a period
of 60 days to study the haemato-biochemical
parameters and nucleotide concentration of the fish.
Fish were stocked in indoor plastic tanks, provided
with 500 l of aerated freshwater in each tank. Each
group was fed to satiation twice a day for 60 days.
Significant differences were observed in haematobiochemical
parameter, RNA concentration and
RNA:DNA ratios with different dietary protein
levels. These parameters showed an increasing trend
with an increase in the dietary protein levels up to
P35 diets (p<0.05), decreased thereafter. Fish fed
with low and high level protein diets showed lesser
values of red blood cells, haemoglobin content,
haematocrit and total plasma protein when compared
with optimum protein level (35.28%). Moreover,
the highest glucose level in plasma was
observed in fish fed with the lowest protein diet
whereas, no significant difference was observed in
their WBC counts. Significantly higher (p<0.05)
muscle RNA and RNA: DNA ratio was found in P35
fed group diets. All these parameters were negatively
affected by the further increase in protein
level in the diet. It may be concluded that the dietary
protein level influences the haemato-biochemical
response and nucleotide concentration of
O. bimaculatus, which showed an increasing trend with increase in dietary protein to optimum level (P35) and decreased after that.