Optimal
dietary protein requirement of juvenile GIFT Tilapia (Oreochromis
niloticus) reared in inland ground saline water
M.
Paul1, P. Sardar1*, N.P. Sahu1, T. Varghese1,
N. Shamna1, V. Harikrishna2, A.D. Deo1,
P.
Jana1, K.P. Singha1, G. Gupta1, M. Kumar1
and G. Krishna3
1Fish Nutrition
Biochemistry and Physiology Division, ICAR-Central Institute of Fisheries
Education, Mumbai-400 061, India
2ICAR-Central
Institute of Fisheries Education, Lahli-124 411, India
3Fish Genetics and
Biotechnology Division, ICAR-Central Institute of Fisheries Education,
Mumbai-400 061, India
*Corresponding
Author Email : parimalsardar0001@gmail.com
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Abstract
Aim:
The present study was conducted to optimize the dietary protein level in the
diet of Genetically Improved Farmed Tilapia reared in inland ground saline
water (IGSW) of 15 ppt ambient salinity.
Methodology: Seven iso-caloric (400 kcal digestible energy,
DE/100g), iso-lipidic (6%) and hetero-nitrogenous (20-50% crude protein, CP)
purified diets were prepared for conducting the feeding trial. Following
completely randomized design, the random distribution of 315 acclimatized
fish (average body weight 4.01±0.01g) was made in seven groups namely, CP20,
CP25, CP30, CP35, CP40, CP45
and CP50 in triplicate with the stocking density of 15 fish per
replicate tank.
Results:
Weight gain percentage, specific growth rate, and expression of insulin like
growth factor-I and insulin like growth factor-I receptor with higher
quadratic relation (R2=0.94, 0.96, 0.90 and 0.93, respectively) to
the dietary crude protein (CP) level significantly increased (p<0.05) up
to 40% crude protein and beyond that the values significantly decreased. With
higher quadratic (R2=0.83) relation, muscle RNA/DNA ratio was
significantly highest in 40% crude protein fed group. With higher quadratic
(R2=0.81 and 0.98, respectively) relations, significantly higher
protease and lower amylase activities were found in 40, 45 and 50% crude
protein fed groups.
Interpretation: Second order polynomial regression
analysis based on WG%, SGR and IGF-I gene expression revealed that the
optimum dietary protein for GIFT juveniles could be 41.84, 40.66 and 42.22%,
respectively. This data will be helpful for development of economic and
environment-friendly feed for GIFT tilapia culture in inland ground saline
water of medium salinity.
Key words: Gene expression, GIFT Tilapia, Growth metrics,
Inland Ground Saline Water
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