Abstract
Eighty four farmed Rainbow trout, Oncorhynchus mykiss ranging from 4.8-38.5cm total length and 1.11-725.00g body weight
were collected for analyses of its body composition from Trout Hatchery, Masote near Kali Matti, Murree and Madian, Swat.
The condition factor value of O. mykiss ranged from 0.831 to 1.607. The mean percentage of water was found 77.82%, for ash
12.77%, for fat 22.79% and for protein content 64.42% in whole dry body weight of O. mykiss. Results showed that there was
a strong correlation (P<0.001) in each of these body constituents (water, fat, protein and ash) with body size, weight and
condition factor of the fish. Thus, with increasing body size, fat and protein contents increased in greater proportion, while ash
and water percentage decreased. An inverse correlation was found in water and ash percentages, whereas percentage fat and
protein showed positive correlation with condition factor.
