Abstract: A study was conducted to assess some heavy metal concentration (Cadmium (Cd), Copper (Cu), Iron (Fe), Lead (Pb) and Zinc (Zn)) in the gills and bones of Oreochromis niloticus obtained from Jega river. 30 fish samples were collected from March to July 2014 (fortnightly). Bones and gills were used for the assessment of some heavy metals using Atomic Absorption Spectrometer. Results indicated that Pb was not detected in both gills and bones but Fe, Cd, Zn and Cu were present in both the gills and bones of the fish samples. The concentrations of heavy metals in gills were; Fe 3.37±1.10, Cd 0.62±0.08, Zn 6.21±0.11 and Cu 1.28±0.10 mg/kg. The concentrations of heavy metals in bones: Fe 13.08±1.00 mg/kg, Cd 0.99±0.06 mg/kg, Zn 1.28±0.10 mg/kg and Cu 2.23±0.20 mg/kg. The results were found to be within the internationally acceptable standard limits. However, the consumption of small amounts of the identified heavy metals in fish could lead to gradual accumulation over a long period of time and exert toxic effects to consumers. Efforts should be made by the Government to provide appropriate channels for waste disposal to reduce impact on fish.
Abstract: This paper analyses the effect of fertilizer (organic and
inorganic) in the growth of tilapia. An experiment was implemented
in the Aquapesca Company of Mozambique; there were considered
four different treatments. Each type of fertilizer was applied in two of
these treatments; a feed was supplied to the third treatment, and the
fourth was taken as control. The weight and length of the tilapia were
used as the growth parameters, and to measure the water quality, the
physical-chemical parameters were registered. The results show that
the weight and length were different for tilapias cultivated in different
treatments. These differences were evidenced mainly by organic and
feed treatments, where there was the largest and smallest value of
these parameters, respectively. In order to prove that these differences
were caused only by applied treatment without interference for the
aquatic environment, a Fisher discriminant analysis was applied,
which confirmed that the treatments were exposed to the same
environment condition.
Abstract: Three purified diets were formulated using fish meal,
soya bean, wheat flour, palm oil, minerals and maltose. The
carbohydrate in the diets was increased from 5 to 15% by changing
the cellulose content to study the effect of dietary carbohydrate level
on the growth parameters of Nile tilapia Oreochromis niloticus. The
protein and the lipid contents were kept constant in all the diets. The
results showed that, weight gain, protein efficiency ratio, net protein
utilisation and hepatosomatic index of fish fed the diet containing
15% cellulose were the lowest among all groups. Addition, the fish
fed the diet containing 5% cellulose had the best specific growth rate,
and food conversion ratio. While, there was no effect of the dietary
cellulose levels on condition factor and survival rate. These results
indicate that Nile tilapia fingerlings are able to utilize dietary
cellulose does not exceed 10% in their feed for optimum growth.
Abstract: Diagnostic enzymes like aspartate aminotransferase
(AST), alanine aminotransferase (ALT) and alkaline phosphatase
(ALP) were determined as indices of heavy metal pollution in Tilapia
guinensis. Three different sets of fishes treated with lead (Pb), iron
(Fe) and copper (Cu) were used for the study while a fourth group
with no heavy metal served as a control. Fishes in each of the groups
were exposed to 2.65mg/l of Pb, 0.85mg/l of Fe and 0.35 mg/l of Cu
in aerated aquaria for 96 hours. Tissue fractionation of the liver
tissues was carried out and the three diagnostic enzymes (AST, ALT,
and ALP) were estimated. Serum levels of the same diagnostic
enzymes were also measured. The mean values of the serum enzyme
activity for ALP in each experimental group were 19.5±1.62,
29.67±2.17 and 1.15±0.27 IU/L for Pb, Fe and Cu groups compared
with 9.99±1.34 IU/L enzyme activity in the control. This result
showed that Pb and Fe caused increased release of the enzyme into
the blood circulation indicating increased tissue damage while Cu
caused a reduction in the serum level as compared with the level in
the control group. The mean values of enzyme activity obtained in
the liver were 102.14±6.12, 140.17±2.06 and 168.23±3.52 IU/L for
Pb, Fe and Cu groups, respectively compared to 91.20±9.42 IU/L
enzyme activity for the control group. The serum and liver AST and
ALT activities obtained in Pb, Fe, Cu and control groups are
reported. It was generally noted that the presence of the heavy metal
caused liver tissues damage and consequent increased level of the
diagnostic enzymes in the serum.
Abstract: Toxicity of copper (Cu), lead (Pb) and iron (Fe) to
Tilapia guinensis was carried out for 4 days with a view to
determining their effects on the liver and muscle tissues. Tilapia
guinensis samples of about 10 - 14cm length and 0.2 – 0.4kg weight
each were obtained from University of Calabar fish ponds and
acclimated for three (3) days before the experimental set up.
Survivors after the 96-hr LC50 test period were selected from test
solutions of the heavy metals for the histopathological studies.
Histological preparations of liver and muscle tissues were randomly
examined for histopathological lesions. Results of the histological
examinations showed gross abnormalities in the liver tissues due to
pathological and degenerative changes compared to liver and muscle
tissues from control samples (tilapia fishes from aquaria without
heavy metals). Extensive hepatocyte necrosis with chronic
inflammatory changes was observed in the liver of fishes exposed to
Cu solution. Similar but less damaging effects were observed in the
liver of fishes exposed to Pb and Fe. The extent of lesion observed
was therefore heavy metal-related. However, no pathologic changes
occurred in the muscle tissues.
Abstract: The objectives of this study were to isolate LAB from various sources, dietary supplement, Thai traditional fermented food, and freshwater fish and to characterize their potential as probiotic cultures. Out of 1,558 isolates, 730 were identified as LAB based on isolation on MRS agar supplemented with a bromocresol purple indicator&CaCO3 and Gram-positive, catalase- and oxidase-negative characteristics. Eight isolates showed the potential probiotic properties including tolerance to acid, bile salt & heat, proteolytic, amylolytic & lipolytic activities and oxalate-degrading capability. They all showed the antimicrobial activity against some Gram-negative and Gram-positive pathogenic bacteria. Based on 16S rDNA sequence analysis, they were identified as Enterococcus faecalis BT2 & MG30, Leconostoc mesenteroides SW64 and Pediococcus pentosaceous BD33, CF32, NP6, PS34 & SW5. The health beneficial effects and food safety will be further investigated and developed as a probiotic or protective culture used in Nile tilapia belly flap meat fermentation.
Abstract: The fish meat plays an important role in the human health as it contains high quality protein. The tilapia fish considered as the third largest group of farmed fish. The oxidative deterioration of fish meat may occur during the cooking process. The proper cooking process and using natural antioxidant to prevent oxidation and enhance the quality of the tilapia fish fillet is necessary. Hence, this research was carried out to evaluate the potential of clove essential oil to prevent lipid peroxidation and enhance the antioxidant activity of tilapia fish fillet cooked using microwaving and grilling methods. The results showed that cooking using microwave significantly (p
Abstract: Fishbone of Nile Tilapia (Tilapia nilotica), waste from the frozen Nile Tilapia fillet factory, is one of calcium sources. In order to increase fish bone powder value, this study aimed to investigate the effect of Tilapia bone flour (TBF) addition (5, 10, 15% by flour weight) on cooking quality, texture and sensory attributes of noodles. The results indicated that tensile strength, color value (a*) and water absorption of noodles significantly decreased (p£0.05) as the levels of TBF increased from 0-15%. While cooking loss, cooking time and color values (L* and b*) of noodles significantly increased (p£0.05). Sensory evaluation indicated that noodles with 5% TBF received the highest overall acceptability score.
Abstract: The purpose of this study was to understand the main
sources of copper (Cu) accumulation in target organs of tilapia
(Oreochromis mossambicus) and to investigate how the organism
mediate the process of Cu accumulation under prolonged conditions.
By measuring both dietary and waterborne Cu accumulation and total
concentrations in tilapia with biokinetic modeling approach, we were
able to clarify the biokinetic coping mechanisms for the long term Cu
accumulation. This study showed that water and food are both the
major source of Cu for the muscle and liver of tilapia. This implied
that control the Cu concentration in these two routes will be correlated
to the Cu bioavailability for tilapia. We found that exposure duration
and level of waterborne Cu drove the Cu accumulation in tilapia. The
ability for Cu biouptake and depuration in organs of tilapia were
actively mediated under prolonged exposure conditions. Generally,
the uptake rate, depuration rate and net bioaccumulation ability in all
selected organs decreased with the increasing level of waterborne Cu
and extension of exposure duration.Muscle tissues accounted for over
50%of the total accumulated Cu and played a key role in buffering the
Cu burden in the initial period of exposure, alternatively, the liver
acted a more important role in the storage of Cu with the extension of
exposures. We concluded that assumption of the constant biokinetic
rates could lead to incorrect predictions with overestimating the
long-term Cu accumulation in ecotoxicological risk assessments.
Abstract: Stocking density is considered one of the important
factors affecting fish growth. But, information related to impact of
stocking density on growth performance of monosex tilapia population
under the ecological conditions of Gangetic plains in West Bengal,
India is limited. The aim of our study was to compare the growth
potential of monosex tilapia at various stocking densities and to
determine an ideal stocking density for culture of all-male monosex
fish. The males were isolated by examination of genital papilla region
and were stocked separately in 0.01 ha earthen ponds at different
stocking densities (5000, 10000, 15000, 20000, 25000 and 30000
fingerlings/ha). It was found that the highest weight, length, daily
weight gain, growth rate and protein content were observed for the
20000 fish/ha density class. Thus, culture of monosex tilapia at a
density of 20000 fish/ha can be considered ideal for augmented
production of the fish under Indian context.
Abstract: Foodborne Salmonella infections have become a
major problem world wide. Salmonellosis transmitted from fish are
quite common. Established quality control measures exist for export
oriented fish, none exists for fish consumed locally. This study aimed
at characterization of Salmonella isolated from Nile tilapia . The
study was carried out in selected beaches along L. Victoria in
Western Kenya between March and June 2007. One hundred and
twenty fish specimens were collected. Salmonella isolates were
confirmed using serotyping, biochemical testing in addition to malic
acid dehydrogenase (mdh) and fliC gene sequencing. Twenty
Salmonella isolates were confirmed by mdh gene sequencing. Nine
(9) were S. enterica serotype typhimurium, four (4) were S. enterica
Serotype, enteritidis and seven (7) were S. enterica serotype typhi.
Nile tilapia have a role in transmission of Salmonellosis in the study
area, poor sanitation was a major cause of pollution at the beach
inshore waters.