THE NUTRITIONAL VALUE OF COW BLOOD MEAL AND ITS EFFECTS ON GROWTH PERFORMANCE, HAEMATOLOGY AND PLASMA ENZYMES OF HYBRID CATFISH

Abstract

The nutritional potential of sun-dried cow blood meal (CBM) was investigated
for its effect on growth performance, haematology and plasma enzyme
activities in hybrid catfish fingerlings (Clarias gariepinus Male x
t-feterobranchus longifilis Female), in an assay that lasted for twelve weeks.
Six graded diets containing 0, 5, 10, 15, 20 and 25 percent of CBM were
compounded. Ten fingerlings (mean weight 4.23+_0.64g) per tank were reared
under laboratory conditions in eighteen plastic tanks, each containing 12
litres af water. 'The fingerlings were fed 3% of their body weight daily, with
bimonthly adjustments. At the end of the 84-day experiment, growth
performance parameters such as weight gains, specific growth rate (SGR) and
feed conversion ratio (FCR) were determined. Blood samples were pooled
from each treatment on days 0, 42 and 84 for haematological and plasma
enzyme analyses.
The specific growth rate and the feed conversion ratio were best in the fish
fed the control (0% sun-dried CBM) diet and poorest in the fish fed 25%
CBM diet inclusion. There were no significant differences (P>0.05) between
mean daily weight gains, specific growth rate and feed conversion ratios of
fish fed diet 2 (5% CBM) and the control diet. The higher the inclusion level
of the sun-dried CBM in the experimental diets, the poorer the nutrient
utilization and growth performance. Haematological and plasma enzyme
analyses revealed progressively severe macrocytic normochromic anaemia,
leucocytosis and high enzymatic activities of plasma alanine
aminotransferase (ALT) and aspartate aminotransferase (AST), gammaglutamyl
transferase (GGT) and alkaline phosphatase (ALP) in fish fed increasing
levels of sun-dried CBM. These enzymatic changes imply liver, kidney and/or
cardiac damage, and opportunistic systemic bacterial infection. It can be
inferred that for optimum growth performance, best nutrient utilization and
unimpaired haematological and plasma enzyme activities in hybrid Clarias, a
5% level of sun-dried CBM inclusion in their diet is recommended.