ABSTRACT
This study was carried out to determine Organosomatic indices of Clarias gariepinus fed diets supplemented with graded levels of Oyster mushroom (Pleurotus ostreatus). Organosomatic indices can be described as the ratios of organs to body. weight when the measured organ in relation to body mass can be directly linked to. some environmental changes (Ronald and Bruce, 1990). It is manifested through. changes in size that are reflected through a reduction or increase, influenced by. Experimental diets were prepared . Diet 1 being the control without mushroom meal and Diet 2, 3, 4 and 5 being the experimental diets with 1.0%, 1.5%, 2% and 2.5% inclusion levels respectively. The experiment was laid out in a Randomized Complete Block Design (RCBD). Each tank was stocked with 63 post juveniles each and fed twice daily to satiation with the prepared feed. The experiment lasted for a period of 9 weeks after which, the different fish organs were randomly extracted three per treatment for Histological studies and data was subjected to analysis of variance at 5% probability.
The slides were generated using Hematoxylin and Eosin as stain at University of Benin Teaching Hospital and later viewed with a microscope connected to a laptop for photomicrograph.
The result showed that T3 had the longest intestine with mean cell length 36.87 ± 3.32 and mean cell width 29 ±3.77 while the least was in T1 with cell length of (30±9.12) and (28±3.66). Highest values were also recorded in the cell length and width of the liver and kidney in T3 and lowest value in T1. But that of cell length and width of the gills was highest in T5 and lowest in T1. The 1.5% inclusion mushroom level in experimental feed gave a better overall result.
At the end of this experiment, the final results obtained confirmed that Oyster mushroom used as a study an additive in the experimental diet improved the appearance and quantity of the offals which invariably will affect or improve the immune response of the fish.
