Ompok under different conditions of life and

Ompok bimaculatus, (Bloch, 1794) popularly
known as Indian butter catfish or pabda a promising aquaculture silurid of
South-East Asian countries (Day 1981) known for its excellent taste,
nutritional profile, soft bony structure, rich lipo-protein content and high
market value (Debnath et al., 2015; Banik, Goswami, and Malla, 2012). It has an
extensive geographical distribution covering Afghanistan, Bangladesh, Myanmar,
Pakistan (Indus plains and adjoining hill areas) and several states of India
including North-eastern States, Odisha, Bihar and West Bengal (Chakrabarti et
al., 2012). It is also considered to be a species which can be diversified
towards both species and culture system diversification (Rawat et al., 2018).
The healthy cultivation of Pabda depends on the nutritional status of the
supplementary feeds. Protein makes up a larger proportion of the fish feed, and
at the same time is also the one of the most important dietary nutrients
influencing growth, reproduction, survival and yield of fish as well as
economics of a farming system by determining the feed cost (Lovell, 1998; Luo
et al. 2004; Siddiqui and Khan, 2009). An ideal dietary protein level should
ensure maximum growth of fish and also maintain good health. Thus, general
haematological analyses could act as a diagnostic tool to assess physiological
or metabolic dysfunctions caused by malnutrition or nutritional deficiency. The
changes in levels of fish blood parameters such as red blood cell, white blood
cell, haemoglobin and hematocrit will considerably provide an insight of fish’s
health status under different conditions of life and environment (Harikrishnan
et al., 2011). Hemoglobin is a protein responsible for transport of O2
and CO2 in fish body, and its attentiveness is closely related to
red blood cell counts (Clark et al., 1979). White blood cells in fish have
immune functional role and can be used to detect certain diseases and injury in
fish body (Qiang et al., 2013). Changes in blood parameters are governed in
part by the nutritional condition of the fish (Kumar et al., 2005; Zhou et al.,
2012). Some researchers have reported that an increased in dietary protein level
could raise haemoglobin concentration and red blood cell counts. (Abdel-Tawwab et
al., 2010; Ahmed and Maqbool, 2017). Similarly, Sakthivel (1988) also reported
that, the haemoglobin concentration, red blood cell count and total white blood
cell of common carp (Cyprinus carpio) at 38% dietary protein level were
significantly higher than those at 14% and 58% dietary protein level.