Date of Award

2003

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Abdu -fatah Al-Sayed

Second Advisor

Dr. Waleed Harnza

Abstract

The present study was conducted to evaluate date pits as an energy source of Nile tilapia fingerlings and adults, in two consecutive experiments. In the first experiment, five isocaloric (450 kcal/100g)-isonitrogenous (35% crude protein) diets containing of date pits as a replacement for wheat bran (energy source) 0, 25, 50, 75 and 100% levels were prepared. The diets were fed to duplicate groups of Nile tilapia, Oreochromis niloticus fingerlings and adults, with average initial weights of 10 and 50g, respectively twice a day, for 70 days. The culture system consisted of 70-L, fiberglass tanks connected together in a closed system. The results indicated that the inclusion of date pits in the diets of both sizes resulted in a significant retardation in growth performance and feed utilization efficiency of Nile tilapia. Body composition was not significantly affect by dietary treatment except for body lipid which was significantly decreased in adult fish fed 100% date pits. The results revealed also that fingerlings fish utilized date pits more efficiently than adult fish.

In the second experiment, 8 isocaloric (450 kcal/100g)-isonitrogenous (35% crude protein) containing 0,25 and 50% date pits, 25 and 50% acid treated date pits, 25 and 50 date pits supplemented with exogenous enzyme and 50% acid treated date pits supplemented with enzymes. The diets were fed to Nile tilapia fingerlings (10g), twice a day for 88 days. The results indicated that the control diet produced better growth performance and feed efficiency ratio than date pits-based diets. Growth performance and feed efficiency were significantly retarded with the increase in date pits levels.

Protein and energy retention and body composition were not significantly affected by date pits levels. Acid treatment and enzyme supplementation did not improve date pits quality.

In conclusion, despite the retardation in the performance of fish fed date pits, the decrease in feed cost may compensate for this retardation. Therefore, about 25% raw date pits could be included in tilapia diets as a replacement of wheat bran

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