Possible Effects of Feeding Fish the Dried-Treated Sewage Sludge: I-Concerning Growth Performance, Feed Utilization and Chemical Composition

Abstract

A field study was conducted to investigate the effects of feeding fish [in a polyculture system consists of four freshwater species, namely Nile tilapia (T), silver carp (Sc), common carp (Cc), and African catfish (Cf)] the sewage (S) sludge comparing with a commercial diet for fish as a control (C) for 102days. From the obtained results, the use of sewage sludge in fish feeding led to lower growth performance. Silver carp reflected better growth performance than Nile tilapia, common carp and catfish, respectively, particularly with feeding the sewage sludge. The best feed utilization was showed by silver carp and Nile tilapia, the worst values with catfish. Nile tilapia fed the sewage sludge showed the best FCR and PER. The best chemical composition of the whole fish body was found with feeding the commercial diet (control). Catfish body contained the highest ash, CP and EC and the lowest EE among all tested fish species. Control tilapia had the lowest ash and EE contents, while highest CP and EC content was found with catfish fed the sewage sludge. Silver carp muscles contained higher DM and CP and lower ash, EE and EC contents among all fish species. The best ash, EE, and CP was determined in silver carp fed the control diet. Nile tilapia showed the highest values for condition factor, dressing and fillet percentages among the tested fish species, the lowest condition factor and dressing with catfish, and the lowest fillet with common carp. Therefore, it is not recommended to use sewage sludge in fish feeding, although its use in cultured fish feeding is wide spreading in Kafr El-Sheikh governorate.

Possible effects of feeding fish the dried-treated sewage on bioaccumulation of metals, morphological lesions and mortality rate

“…The negative effect of feeding DSS on the mortality rate may be due to its very high content of ash and very low percentages of EE and total carbohydrate comparing to the commercial (control) diet (Table 1), as well as due to the long period of exposure time (102 days). That affected also negatively the growth performance and feed utilization (Abdelhamid et al, 2014, complementary study to the present study). Also, the present study suggests a strong link between metals bioaccumulation in rearing water, fish body and muscles from one side and the morphological lesions and the survival rateof the experimental fish from the other side.…”

Comparative Growth of Different Catfish and Carps under Sewage Treated Water

“…The maximum feed conversion ratio was between days 10 and 20. Nile tilapia fed with the sewage sludge showed the best feed conversion ratio (3.18) compared to silver carp and common carp (Abdelhamid et al 2014). Liney et al (2006) reported that after 3 months of rearing in 80 % secondary treated waste water.…”

Effect of Dietary Inclusion of Sieving Wastes of the Egyptian Clover Seeds Instead of Soybean Meal for Tilapia

“…Although many people in Kafr El-Sheikh Governorate (as the highest governorate allover Egypt in producing fish) talk about sewage using in fish nutrition; yet, different freshwater fish species (Nile tilapia, silver carp, common carp, and African catfish) reflected low values of all tested measurements (growth, feed utilization, and fish body composition, dressing, and boneless meat) by their feeding with sewage comparing with those fed commercial-artificial diet. Thus, Abdelhamid et al (2014) recommended do not feeding fish with treated sewage. Final total length and condition factor of the experimental fish The calculated condition factor (CF) of the experimental fish at the start of the experiment was 2.018%, since the initial body weight and total length were 17.3 g and 9.5 cm, respectively.…”