International Journal of Aquaculture, 2017, Vol.7, No.1, 1
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Fish were homogenized individually for whole body composition and frozen at-18°C for proximate chemical
analysis at the laboratory of the faculty of Agriculture at Minufiya University. Samples were analyzed as follows:
dry matter after desiccation in an oven (105°C for 24 h), crude protein (micro kjeldahl, N x 6.25), and crude lipid
(ether extraction by soxlhet method).
1.4 Blood analysis
After 12-week feeding study 6 fish per treatment were randomly sampled and about 1 ml of fish blood from the
caudal vein was drawn and transmitted into a heparinized tube. The plasma was obtained after blood centrifuged at
1500 x g for 5 minutes at room temperature (24°C) and was stored at -18°C for biochemical analysis.
1.5 Histological analysis
Six fish per treatment were randomly selected and sacrificed. The viscera were separated and well-kept in 10%
neutral buffered formalin (Thermo Fisher, Kalamazoo, MI) for 48 h. The following day, the viscera were washed
with water several times and preserved in 75% ethyl alcohol for further processing. The liver, intestine and gonads
were separately dissected and examined according to standard histological techniques. All tissues were
longitudinally sectioned. Sections were cut to 5 µm increments, mounted on glass slides and stained routinely with
hematoxylin and eosin (H&E) stain for examination through the light electric microscope (Banchfort et al., 1996).
1.6 Statistical procedure
A one way ANOVA test was used to test the differences among dietary treatments. The percentage data of weight
gain and specific growth rate were arcsine transformed before the ANOVA analysis. Differences were considered
significant at the P < 0.05. The differences among means were determined using Duncan ´s multiple range test
(Duncan, 1955).
2 Results
2.1 Growth performance
The performance parameters of Nile tilapia to moringa leaves meal as feed additives in the experimental diets are
illustrated in (Table 2). The results showed that there were no significant differences in final body weight (FBW),
weight gain (g/fish), weight gain (%), and SGR (% day
-1
) among fish groups fed different diets. However, there
were no significant differences (P > 0.05) in survival rates % among the different treatments. Fish fed diet D1
showed the highest growth performance in terms of final body weight (g/fish), gain in weight (g/fish), gain in
weight (%) and specific growth rate (SGR % day
-1
) compared with others during feeding trial (Table 2, Figure 1).
While fish fed diet D4 showed the lowest results of final body weight, gain in weight, gain in weight (%) and
specific growth rate. Also, feed utilization parameters in terms of FCR, FER, FI, PI, and PER of fish fed diet D4
exhibited the same trend.
2.2 Carcass composition
The body composition of the experimental fish at the end of the feeding trial as affected by different levels of
moringa leaves meal as feed additive are shown in Table 3. The moisture content among the different treatments did
not differ significantly (P > 0.05). The lowest value (72.5%) was observed with fish fed D1 diet without
supplementation. The protein, lipid and ash content of fish bodies among treatments are illustrated in Table 3. The
highest value of protein content was observed with fish fed diet supplemented with 4 g kg
-1
moringa leaves meal
(66.2). The lipid values decreased with increasing the inclusion of moringa leaves meal (Table 3). Whereas, the
highest value of ash content was observed with fish fed diet supplemented with 6 g kg
-1
moringa leaves meal (12.2).
2.3 Biochemical parameters
The effects of moringa leaves meal as feed additives in the experimental diets for Nile tilapia on blood components
are presented in Table 4. Among diets contained different levels of moringa leaves meal, fish fed diet D3 detected
low value of total protein (6.2 g/dl) while fish fed diet D4 obtained the highest value (9.3 g/dl). The concentrations
of glucose, cholesterol and triglycerides were varied significantly between all treatments (P < 0.05). Fish fed diet D3
exhibited low value blood glucose (35.3 mg/dl), while the low value of blood cholesterol and triglycerides was
