Microbial quality of tilapia reared in faecal contaminated ponds

96 Microbial quality of tilapia reared in four faecal-contaminated fishponds was investigated. One of the fishponds (TDP) received treated sewage with an average faecal coliform count of https://www.w3.org/1998/Math/MathML" display="inline"> 4 × 10 3 cfu/100ml, and was fed on fresh duckweed grown on treated sewage. Number of faecal coliform on duckweed biomass ranged between https://www.w3.org/1998/Math/MathML" display="inline"> 4 . 1 × 10 2 to https://www.w3.org/1998/Math/MathML" display="inline"> 1 . 6 × 10 4 cfu/g fresh weight. The second fishpond (TWP) received treated sewage and was fed on wheat bran. The third fishpond (FDP) received freshwater and was fed on the same duckweed. Pond 4 (SSP) received only settled sewage with an average faecal coliform count of https://www.w3.org/1998/Math/MathML" display="inline"> 2 . 1 × 10 8 /100ml. The average count in the fishponds were https://www.w3.org/1998/Math/MathML" display="inline"> 2 . 2 × 10 3 , https://www.w3.org/1998/Math/MathML" display="inline"> 1 . 7 × 10 3 , https://www.w3.org/1998/Math/MathML" display="inline"> 1 . 7 × 10 2 and https://www.w3.org/1998/Math/MathML" display="inline"> 9 . 4 × 10 3 cfu/100ml in TDP, TWP, FDP and SSP, respectively. The FDP had significantly ( https://www.w3.org/1998/Math/MathML" display="inline"> p < 0 . 05 ) lower faecal coliform count than the treated sewage-fed ponds and SSP. Microbial quality of tilapia indicated that all tissue samples were contaminated with faecal coliform except the muscle tissues. Ranking of the faecal coliform contamination showed a decrease in the order intestine https://www.w3.org/1998/Math/MathML" display="inline"> > gills > skin > liver . Poor water quality (ammonia and nitrite) in SSP resulted in statistically higher faecal coliform in fish organs of about one https://www.w3.org/1998/Math/MathML" display="inline"> log 10 than in treatments with good water quality. Pre-treatment of sewage is therefore recommended.