EFFECTS OF pH ON GROWTH INDEX, BLOOD PHYSIOLOGICAL PARAMETERS AND SOME OF DIGESTIVE ENZYMES OF THE NILE TILAPIA FISH, Oreochromis niloticus (LINNAEUS, 1758)

Abd El-Ghaffar, H.A.1 and T.M. Abu El-Nasr2

1Spawning and Fish Physiology Department, Central Laboratory for Aquaculture Research, Abbassa, Abu Hammad, Sharkeya.

2Zoology Department, Faculty of Science, Zagazig University.

Dr_Haytham1983@hotmail Tahermaae@zu,edu.eg

Abstract

A total of 90, Oreochromis niloticus (L.) of a mean initial weight (22.53 ± 0.09g) were collected from Abbassa fish farm, Sharkia, Egypt and randomly distributed in nine aquaria representing three treatments with three replicates, pH (6, 7 and 8.5), during the experimental period 45 days. The examined fishes were fed on 25% protein diets with 2 % of fish weight daily “5 days a week”. Sulfuric acid and Sodium hydroxide were used to maintain the acidic and alkaline media in aquaria respectively. The physico-chemical measurements were tested. The results showed that the daily fish weight gained ranged from (0.25 ± 0.0001 to 0.41 ± 0.003 g. The best specific growth rate (SGR) was (1.34 ± 0.006) recorded in the third treatment. Total hardness was significantly decreased by increasing pH values. pH had significant effects on all blood and Physiological parameters measured. The digestive enzymes, amylase and lipase were highly significant in the alkaline treatment. Lowest value of insulin was (0.17 ± 0.03 µIU/mL) recorded in the alkaline treatment while the lowest value of iron was (27.37 ± 1.46 μg/dL) obtained in the acidic treatment.

Keywords: Physiological parameters, pH values, Nile Tilapia, RBCs, Hb, amylase, lipase, and Abbassa Egypt.