EFFECT OF DIETRY PROTEIN LEVELS ON WATER QUALITY OF TILAPIA (OREOCHROMIS NILOTICUS )PONDS | ||||
| Veterinary Medical Journal (Giza) | ||||
| Volume 46, Issue 4, October 1998, Page 895-904 PDF (2.92 MB) | ||||
| DOI: 10.21608/vmjg.1998.377383 | ||||
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| Authors | ||||
| FATMA A. HAFEZ* 1; EL-SHERBINY E. AMAL2; A.Z SOLIMAN2; H.M. A, ABD-ALGHANY1 | ||||
| 1Central Laboratory for Aquaculture Research at Abbassa, Agriculture Research Center. | ||||
| 2Animal Production Department, Faculty of Agriculture, Cairo University. | ||||
| Abstract | ||||
| The experimental work was conducted to study the effects of dietary protein levels on water quality. Fifteen floating circular cages were used as culture units throughout this work. Three cages per treatment were used and placed in each of the five concrete ponds. Nile tilapia (oreochromis niloticus) fingerlings were stocked In each cage at a rate of 40 fish/cage. Averages body Weight ranged from 55 to 60 g and 14 to15 cm length. Four commercial diets containing different Protein levels being 12 (T1), 19 (T2), 26(T3) 32% crude protein (CP) (T4) were used In this Study. A treatment without supplemental Feed (To) was included as a blank. The diets were fed at rate of 3% of live body weight per day, 7Days a Week, divided into two equal feedings per day during the 20 weeks experimental period. Results show that water temperature during the experimental Period ranged between 29.12 and 29.52%c while the dissolved oxygen content was ranged between 6.75 and 9.16mg/l These two parameter within the optimum level for growth of tilapia fish. Salinity values were highest for diets containing high protein levels the decreased to 0.2 and 0.18 ppt for no feed (To) and 12% CP (T1), respectively. The salinity values were in the range found suitable for growth of tilapia which lies between 8.62 to 9.55. The concentration of unionized ammonia (NH3) were ranged between 0.44 and 0.92 ppm for diets containing 12% CP and 32% CP, respectively. The values did not affect the growth of the fish in this experiment. The values of Secchi disk were ranged between 33.27 and 60.63 cm. The values of total phosphorus were ranged between 0,34 to 0.83. These values were related to the treatments of the diets. The available phosphorus were the highest for the high protein diet groups (26% and 32%CP). Nitrate NO3 (mg/1) values indicated that there were nitrate in the water in case of high protein level. The high concentration of phytoplankton and zooplankton was observed for the 32% CP and 26% CP treatments. It was found that phytoplankton existed in the fish intestine. | ||||
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