ABSTRACT
CHAPTER 3 Equilibrium and capacity data of Pratley clinoptilolite
5.3 Results
0 15 30 45 60 75 90
1 6 11 16 21 26
Ammonia concentration (mg L) 1.0 - 1.4 (mm)
0.7 - 1.0 (mm) Control
0 2 4 6 8 10 12 14
1 6 11 16 21 26
Nitrite concentration (mg L)
0 3 6 9 12 15 18
1 6 11 16 21 26
Experimental period (days)
Nitrate concentration (mg L)
Figure 5.3: Measured average concentrations of ammonia, nitrite and nitrate concentrations in the culture tanks for the three different treatments over the 26-day experimental period. Each data point represents an average concentration of three tanks or replicates.
The pH throughout the 26 experimental days ranged from 6.2 - 8.3, while the temperature ranged from 18.2 to 27.2 °C. Dissolved oxygen concentration in the tanks ranged from 7.5 to 9.5 mg L-1 (Table 5.2). Daily average variations in pH, oxygen and temperature of three replicates per three treatments are presented in figure 5.4.
Table 5.2: Water quality parameters of culture water for the three treatments (± standard deviations).
TREATMENT
Replicates pH Dissolved oxygen (mg L-1) Temperature (°°C) (Particle size mm) (tanks) mean mean ±±σσ mean ±±σσ1.0 - 1.4 1 7.70 8.4 ± 0.38 22.9 ± 1.55
2 7.34 8.3 ± 0.37 22.9 ± 1.66
3 7.27 8.5 ± 0.43 22.0 ± 1.65
0.7 - 1.0 1 8.14 8.5 ± 0.37 21.8 ± 1.66
2 7.02 8.6 ± 0.38 21.9 ± 1.72
3 6.93 8.6 ± 0.41 21.9 ± 1.72
Control 1 7.04 8.4 ± 0.49 22.1 ± 1.60
2 7.18 8.4 ± 0.43 22.3 ± 1.66
3 7.15 8.4 ± 0.37 22.8 ± 1.72
6.0 6.5 7.0 7.5 8.0 8.5
1 6 11 16 21 26
pH 1.0 - 1.4 (mm)
0.7 - 1.0 (mm) Control
16 18 20 22 24 26 28
1 6 11 16 21 26
Experimental period (days)
Temperature (ºC)
Figure 5.4: Average daily variations in pH, dissolved oxygen concentrations and temperature for three different treatments throughout the experimental period
6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0
1 6 11 16 21 26
Dissolved oxygen (mg L-1 )
The mean feed conversion ratio was 3.5, 3.7 and 3.5 for the 1.0 - 1.4 mm, 0,7 -1.0 mm and control treatments, respectively. The mean estimated FCR value for all the tanks was 3.5 ± 0.45, and FCR values ranged from 2.97 to 4.1 over all treatments (Table 5.3). The mortality rates of the treatment groups were similar and low with a mean value of 4 % (range 0 - 10 %). Cumulative mortality was less than 10 % and did not differ significantly between treatment tanks (p > 0.05).
Table 5.3: Production characteristics of the guppy (Poecilia reticulata) for three different treatments in relation to daily feed intake and mass gain (wet mass).
TREATMENT (Particle size mm)
Replicates (tanks)
Final fish #
Daily food fed as DM*
(g)
Total food fed as DM (g)
Initial fish mass (g)
Final fish mass (g)
Mass gain (g)
FCR
1.0 - 1.4 1 27 0.30 7.50 6.00 8.41 2.41 3.11
2 28 0.30 7.44 5.95 8.29 2.34 3.18
3 30 0.29 7.31 5.85 7.71 1.86 3.93
0.7 - 1.0 1 29 0.29 7.31 5.85 7.62 1.77 4.13
2 28 0.31 7.65 6.12 8.32 2.20 3.48
3 29 0.30 7.52 6.02 8.14 2.12 3.55
Control 1 30 0.31 7.76 6.21 8.09 1.88 4.13
2 29 0.30 7.54 6.03 8.27 2.24 3.36
3 28 0.32 7.89 6.31 9.06 2.75 2.87
Note: * DM = dry matter and # = number
There was no significant difference in body composition including moisture (73 - 75 %) and crude protein (49.5 - 54.0 % DM) between fish of all treatments and the 30 randomly selected fish at the start of the experiment (Table 5.4). Average crude protein content was estimated as 51.6 ± 1.7 % (13.4 % on wet mass basis). Faecal protein content on a dry matter basis ranged from 48 % to 53 % with an average of 49.7 % (table 5.5). Similarly, there was no significant difference (P > 0.05) among treatments in faecal protein content.
Table 5.4: Results of the Micro-Kjeldahl analysis and moisture content of the guppy (Poecilia reticulata) for three different treatments.
TREATMENT (Particle size mm)
Replicates Wet mass (10 fish)
Dry mass (10 fish)
% moisture content
% protein in sample (DM)
Weight gained as DM (g)
N in gained weight (mg)*
1.0 - 1.4 1 2.82 0.75 73.4 52.84 0.63 53.57
2 2.67 0.69 74.2 53.23 0.62 52.39
3 2.64 0.72 72.7 50.80 0.49 39.75
0.7 - 1.0 1 2.80 0.71 74.6 53.95 0.47 40.17
2 2.36 0.62 73.7 52.35 0.58 48.45
3 2.71 0.72 73.4 49.49 0.56 44.13
Control 1 2.50 0.66 73.6 49.88 0.49 39.44
2 2.50 0.67 73.2 52.65 0.59 49.61
3 3.37 0.86 73.5 49.63 0.72 57.42
Initial 30 fish 1 6.55 1.72 73.7 52.27
Note: * Conversion factor for nitrogen content was 6.25
Table 5.5: Results of the Micro-Kjeldahl analysis for the protein and nitrogen content of the collected faeces from the three different treatments
TREATMENT (Particle size mm)
Replicates Total weight collected (gram)
% protein in sample
Protein in faeces (gram)
Nitrogen in faeces (mg)
1.0 - 1.4 1 1.94 48.89 0.95 151.74
2 1.86 50.57 0.94 150.50
3 1.73 49.46 0.86 136.91
0.7 - 1.0 1 2.02 48.53 0.98 156.86
2 1.63 48.37 0.79 126.15
3 2.03 49.70 1.01 161.42
Control 1 1.83 52.79 0.97 154.56
2 1.66 51.15 0.85 135.86
3 1.53 47.95 0.73 117.38
Note: * Conversion factor for nitrogen content was 6.25
Table 5.6 shows how the nitrogen offered to the fish from the feed was utilised under the different treatments and cases I, II and III. Less then 11 % of the nitrogen fed was converted into body protein. The rest was excreted as solid and soluble waste. There was no significance difference in the various constituents of the nitrogen budget between treatments (p > 0.05) and among the three cases. Average N percentage composition for all treatments was 10 %, 30%, and 60 % for NR, NW, and NS, respectively (Table 5.7).
However, there was a very small difference between the total nitrogen input from feed (NI) and the total nitrogen (Ntotal) that was calculated as a sum of the endogenous and exogenous nitrogen sources (NS + NR + NW). Average Ntotal was +1 %, -1 % and +0.8%
less or greater than NI for the 0.7 - 1.0 mm, 1.0 - 1.4 mm and control treatments, respectively for the all Cases. The mass balance estimation calculated using Case I for the treatment with the 0.7 - 1.0 mm particle size range is presented in figure 5.5.
Table 5.6: Total nitrogen budget (mg) in the culture water of P. Reticulata using the 38 % crude protein diet and estimated ammonia CEC values for the two particle sizes, for the three different cases. The results are averages of the three replicates. There were no significant differences among treatments
CASE Treatment or particle size (mm)
NI NDI NR NW NU NN NZ NS Ntotal Estimated
NH4+ CEC (mg g-1)
Estimated NH4+ CEC (meq g-1)
I 1.0 - 1.4 468.97 18.04 48.57 146.38 125.34 77.31 202.65 468.95 3.96 0.28
0.7 - 1.0 468.97 18.04 44.25 148.14 102.54 102.66 205.20 468.95 5.26 0.38
Control 490.05 18.85 48.83 141.05 228.87 71.35 290.93 490.10
II 1.0 - 1.4 255.78 18.04 26.15 1.12 125.34 97.30 249.90 4.99 0.36
0.7 - 1.0 255.78 18.04 23.83 1.03 102.54 129.32 256.71 6.63 0.47
Control 18.85
III 1.0 - 1.4 468.97 18.04 48.57 146.38 125.34 66.33 466.15 3.40 0.24
0.7 - 1.0 468.97 18.04 44.25 148.14 102.54 107.27 472.39 5.50 0.39
Control 490.05 18.85 48.83 141.05 228.87 79.53 498.27
* NU = sum of daily nitrogen accumulation in solution after zeolite absorption, nitrification and/or volatilisation.
From the nitrogen budget data, the mean ammonia CEC values for Case I, II and III were estimated as 5.80 mg g-1 and 4.12 mg g-1 for the 0.7 – 1.0 and 1.0 – 1.4 mm particle sizes, respectively. There were no significant differences (p > 0.05) in the CEC estimates for all three cases (Table 5.6). There were also no significant differences between estimated CEC values of the two particle sizes (p > 0.05).
Table 5.7: Total nitrogen budget (%) in the culture water of P.Reticulata for the three treatments using the 38% protein diet for the different three cases (values are percentages of the total nitrogen in the food consumed)
CASE Treatment (mm)
NU NR NW NZ NN NZ + NN Ntotal
I 1.0 - 1.4 26.7 10.4 31.2 16.5 15.2 31.7 100.0
0.7 - 1.0 21.9 9.4 31.6 21.9 15.2 37.1 100.0
Control 47.7 10.0 28.8 14.6 100.0
II 1.0 - 1.4 49.0 10.2 0.4 38.0 97.7
0.7 - 1.0 40.1 9.3 0.4 50.6 100.4
Control
III 1.0 - 1.4 26.7 10.4 31.2 14.1 17.0 31.1 99.4
0.7 - 1.0 21.9 9.4 31.6 22.9 16.9 39.8 102.7
Control 47.7 10.0 28.8 16.2 101.7
Total food N (100 %)
Uneaten food N N ingested by fish
N excreted N retained in
body mass (9.4 %) Faecal N
Soluble N (59 %)
N in solids (31.6 %)
N absorbed by zeolite (21.9 %) N still in culture
water (21.9%)
N lost to atmosphere or unaccounted for (0.004 %) Deamination
Urinary and ammonia N
N used by nitrification (15.2 %)
Figure 5.5: A mass balance estimation of nitrogen (N) for the treatment with the 0.7 - 1.0 mm clinoptilolite particle size (Case I). Dashed lines indicate the nitrogen types that were measured