|
|
|
Figure 1: Mean values of weight at 20 day intervals of catfish fed different form of taro leaves as protein source replacing soybean meal |
| Back to contents |
The main of the experiment was studied taro leaf utilization as protein replacement for soybean meal on the growth performance of catfish (Pangasius hypophthalmus) in 5 m2 each concrete pond (2.5m*2m) with 1 m depth. A total of 225 catfish fingerlings were fattening for one month before started experiment with fish stocking density was 3 fish/m2. The average initial weight was 8.89, 8.62, 10.9, 7.98, 8.84g for cooked, dried, ensiled, fresh taro leaves and soybean meal treatment respectively. All feed were mix with rice bran and balance with crude protein (20% in DM basis) and offered at 5% in DM basis of the fish body weight. The experiment design was Completely Randomized Design (CRD) with 5 treatments and three replications within each treatment. The treatments were soybean meal (SB), fresh taro leaf (FTL), dried taro leaf (DTL), ensiled taro leaf (ETL) and cooked taro leaf (CTL). The experimental feeds were carried out over a period of 100 days.
Through the experiment showed that daily weight gain was highest on SB and CTL diet and lowest on DTL, ETL and FTL (P<0.001), while length gain and ratio of weight and length were highest on SB diet (P<0.001) than taro leaves processing but fish survival was not different among treatments (P>0.05). The fish yield was highest values for SB (2472kg/ha) and CTL (1514kg/ha) diet but lowest was DTL (1058kg/ha), ETL (1064kg/ha) and FTL (1150kg/ha) (P<0.001). Water parameter showed did not different among treatments (P>0.05) but water transparency was lowed on ETL (14.7cm) treatment but other treatments were not different. It is concluded that taro leaves can be used successful for growing catfish by supplement them with agriculture by-product.
In Cambodia, rice and fish products have been considered as the major means of generating food. Fisheries are one of the most important sectors, playing an important role in the daily food production and contributing to the national economy. Especially the freshwater fisheries are one of the most productive in the world due to the presence of large floodplains around the Great Lake and along the Tonle Sap and the Mekong Rivers of Cambodia (FAO 2005). However, the amount of all kinds of fish has decreased yearly because of the human illegal activities and it affects the livelihood of the smallholders who depend on fishing. Fish culture is another alternative for farmers to produce food and income to support their family. The fish that can be raised by smallholders should survive on whatever the farmers have to feed such as natural resources which are cheap and available in the region.
Catfish (Pangasius hypophthalmus) is omnivorous fish that eat whatever you gave them (Pets & animals 2009). Therefore, it can survive on feeds that the farmers have especially green forages and crop byproducts. This kind of fish is also raised by large amount of smallholders around the Great Lake of Cambodia.
Green forages are locally valuable and have low cost for farmers to use as feeds for fish. Moreover, they are also a good source of nutrition including protein, vitamins and minerals. The dominant green forages grown by smallholders are water spinach, sweet potato, cassava, taro leaf and duckweed. Taro leaf or foliage has been much focused and research for using as animal feed especially pigs which could be most potential as protein sources (Pham Sy Tiep et al 2006; Rodríguez et al 2009a,b; Du Thanh Hang and Preston 2010; Hang D T and Preston T R 2009 and Chhay Ty et al 2010). However, less research has been done to use this forage for fish feed. Therefore, new research should be encouraged with fish that smallholder farmers like to raise.
The objective in this experiment is to study effect of taro (Colocasia esculenta) leaves utilization as protein replacement for soybean meal on the growth performance of catfish (Pangasius hypophthalmus)
The experiment was carried out at the Center for Livestock and Agriculture Development (CelAgrid) located in Prah Theat village, Sankat Rolous, Khan Dangkor approximately 25 km from Phnom Penh city. The experiment was conducted from 20th July to 28th October 2011 during the period of 100 days.
A total of 15 concrete ponds were lined with white plastic sheet to avoid filtration of water. After paving the white plastic, water from cannel was pumped into all experimental ponds. The area of each pond was 5 m2 (2.5 m length x 2 m wide) with 1 m deep.
Total 225 catfish (Pangasius hypophthalmus) fingerlings were bought from the fish hatchery farm at Preak Phnov, near Phnom Penh city. The fingerlings were fattening for one month before started experiment. Fish stocking density were 3 fish/m2. The average initial weight was 8.89, 8.62, 10.9, 7.98, 8.84g for cooked, dried, ensiled, fresh taro leaves and soybean meal treatment.
Taro leaves were harvested from ponds in the region around CelAgrid and rice bran was purchased from rice mill near the CelAgrid, while soybean meal was purchased from animal feed shop in Phnom Penh city. Taro leaves were fed to catfish in different from such as fresh, dried, ensiled and cooks form. Dried taro leaves form were sun-dried for 4-5 days prior to grinding into dried taro leaves meal. Ensiled form was ensiled with sugar palm syrup at level of 5% and store for one month before feeding. Cook form was cooked every day before feeding to catfish and fresh form was chopped in to very small piece (0.5-1cm). All feed were mix with rice bran and balance with crude protein (20% in DM basis).
|
Table 1: Planned composition of the diets, % DM basis (based on prior analysis of the ingredients) |
|||||
|
Ingredients |
Treatment# |
||||
|
CTL |
DTL |
ETL |
FTL |
SB |
|
|
Rice bran |
40 |
29 |
33 |
39 |
73 |
|
Fresh taro leaf |
0 |
0 |
0 |
61 |
0 |
|
Dried taro leaf |
0 |
71 |
0 |
0 |
0 |
|
Ensiled taro leaf |
0 |
0 |
67 |
0 |
0 |
|
Cook taro leaf |
60 |
0 |
0 |
0 |
0 |
|
Soybean meal |
0 |
0 |
0 |
0 |
27 |
|
Total |
100 |
100 |
100 |
100 |
100 |
|
%CP in DM |
20.1 |
20.1 |
20.4 |
20.0 |
20.3 |
|
% DM |
40.4 |
85.4 |
40.0 |
46.3 |
89.4 |
|
# FTL: Fresh taro leaf, DTL: Dry taro leaf, ETL: Ensiled taro leaf, CTL: Cook taro leaf, SB: Soybean meal |
|||||
Fish were fed twice daily at 8:00 am and 4:00 pm. The feed offered was 5% DM basis of the fish body weight. The experimental feeds were carried out over a period of 100 days.
The experiment design was Completely Randomized Design (CRD) with 5 treatments and three replications within each treatment.
The treatments were
SB: soybean meal and rice bran
FTL: Fresh taro leaf and rice bran
DTL: Dried taro leaf and rice branETL: Ensiled taro leaf and rice bran
CTL: Cooked taro leaf and rice bran.
The oxygen and pH of the water in the fish ponds were measure weekly and each measurement was taken twice at 6:00 am and at 4:00 pm using the O2 test kid. The water temperature was measured every 3 days and each was taken three measurements at 6:00 am, at 12:00 am and at 5:00 pm) using thermometer placing in each pond for 5 minutes. A water transparency was also being measured at 12.00 am once in every 2 weeks using Secchi disk.
Rice bran, soybean meal and different form of taro leaves were analyses for DM and CP (N*6.25). The DM content was determined using Oven under method of Undersander et al (1993). N was analyzed following procedures of AOAC (1990).
Fish sampling was done every 20days in order to determine the growth rate of the fish by recording the length and weight of sample. The fish were caught with a seine net and five fish were taken randomly as the sample and weighed by electronic balance. The length from the tip of the mouth to the caudal fin was measured with a ruler. At the end of the experiment the total fish biomass was harvested and the weight, length, mortality were recorded.
Daily weight gain and daily length gain were measurement by the following equations:
DWG (g/day) = (Wf – Wi)/Dt
Where: Wf = Final weight (g)
Wi = Initial weight (g)
Dt = Total experiment days
DLG (cm/day) = (Lf – Li)/Dt
Where: Lf = Final length (cm)
Li = Initial length (cm)
Dt = Total experiment days
The survival rate of the fish was determined by the following equation:
SR (%) = (Tfn/Tin) x 100
Where Tfn = Total final fish number (head)
Tin = Total initial fish number (head)
Daily increases in weight, length, mortality and yield of the fish were determined by linear regression with days as the independent variable. The data was analyzed by Analysis of Variance (ANOVA) using the General Linear Model software of Minitab version 15.1.2. The sources of variance were treatment and error. When the F-test was significant at P<0.05, pair wise comparisons were performed using Turkey’s procedure (Minitab Statistical Software). The model used was:
Yij = μ + Ti + eij
In where, Yij = Dependent variables
μ = overall mean
Ti = treatment effect (i=1-5)
eij = random error
The dry matter content of ingredients were high on soybean meal (87.4), rice bran (87.6) and dry taro leaves (83.1%) while the lowest was fresh, ensiled and cook taro leaves (Table 2). The CP content of soybean meal (47.0%) was high value nearly double compared with taro leaves which range from 23.7-26.2% in DM basis.
|
Table 2: Chemical composition of ingredients |
||
|
|
% Dry matter |
% Crude protein in DM |
|
Cook taro leaves |
8.05±0.03 |
26.2±0.019 |
|
Dry taro leaves |
83.1±0.03 |
23.7±0.021 |
|
Ensiled taro leaves |
15.6±0.04 |
24.7±0.035 |
|
Fresh taro leaves |
18.2±0.01 |
26.1±0.007 |
|
Soybean meal |
87.4±0.07 |
47.0±0.011 |
|
Rice bran |
87.6±0.13 |
10.1±0.018 |
In table 3 showed the mean value of feed offer per pond. Total feed offer in fresh basis were observed high on cook taro leaves (CTL) treatment, then ensiled taro leaves (ETL) and fresh taro leaves (FTL) but poorest were dry taro leaves (DTL) and soybean meal (SB) treatment (P<0.001). The different in feed offer in fresh form might be effect from dry matter content which was lowed in cook, ensiled and fresh taro leaves compared with other two treatments and numbers of fish were variable in each pond cause of mortality of fish. Meanwhile, when converted in total feed offer in dry basis and crude protein showed that CTL still higher than other treatment (P<0.001).
|
Table 3: Feed offer per pond of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment# |
|
|
||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Offer in fresh basis |
|
|
|
|
|
|
|
|
Cook taro leaves |
197.4 |
0 |
0 |
0 |
0 |
|
|
|
Dry taro leaves |
0 |
19.0 |
0 |
0 |
0 |
|
|
|
Ensiled taro leaves |
0 |
0 |
98.8 |
0 |
0 |
|
|
|
Fresh taro leaves |
0 |
0 |
0 |
64.2 |
0 |
|
|
|
Soybean meal |
0 |
0 |
0 |
0 |
6.19 |
|
|
|
Rice bran |
10.9 |
5.89 |
7.02 |
8.85 |
19.3 |
0.37 |
|
|
Total |
208.4a |
24.9b |
105.9c |
73.1d |
25.4be |
3.19 |
<0.001 |
|
Offer in DM basis |
|
|
|
|
|
|
|
|
Cook taro leaves |
16.3 |
0 |
0 |
0 |
0 |
|
|
|
Dry taro leaves |
0 |
15.7 |
0 |
0 |
0 |
|
|
|
Ensiled taro leaves |
0 |
0 |
15.5 |
0 |
0 |
|
|
|
Fresh taro leaves |
0 |
0 |
0 |
11.7 |
0 |
|
|
|
Soybean meal |
0 |
0 |
0 |
0 |
5.38 |
|
|
|
Rice bran |
9.50 |
5.08 |
6.12 |
7.70 |
16.7 |
0.31 |
|
|
Total |
25.8a |
20.8bcde |
21.6c |
19.4d |
22.1e |
0.64 |
<0.001 |
|
Offer in CP in DM basis |
|
|
|
|
|
|
|
|
Cook taro leaves |
4.25 |
0 |
0 |
0 |
0 |
|
|
|
Dry taro leaves |
0 |
3.72 |
0 |
0 |
0 |
|
|
|
Ensiled taro leaves |
0 |
0 |
3.82 |
0 |
0 |
|
|
|
Fresh taro leaves |
0 |
0 |
0 |
3.04 |
0 |
|
|
|
Soybean meal |
0 |
0 |
0 |
0 |
2.52 |
|
|
|
Rice bran |
0.95 |
0.50 |
0.61 |
0.77 |
1.67 |
|
|
|
Total |
5.19a |
4.22bcde |
4.43ce |
3.80d |
4.19de |
0.12 |
<0.001 |
|
# FTL: Fresh taro leaf, DTL: Dry taro leaf, ETL: Ensiled taro leaf,
CTL: Cook taro leaf, SB: Soybean meal
|
|||||||
The daily weight gain of catfish showed that in the first two steps did not showed any different on weight gain (P>0.05) but later on daily weight gain were effect on taro leaves processing (P<0.001) but in the overall, daily weight gain was found high on SB and CTL treatment (P<0.001) but not different for DTL, ETL and FTL treatment. The daily weight gain on taro leaves processing treatment in this study ranged with study of Nguyen Duy Quynh Tram et al (2007) (0.47g) when hybrid catfish fed biodigester effluent but lower than SB treatment in this study.
|
Table 4: Mean value of weight gain of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment # |
|
|
||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Weight gain, g/day |
|
|
|
|
|
|
|
|
0-20 |
0.24 |
0.22 |
0.23 |
0.20 |
0.19 |
0.053 |
0.962 |
|
20-40 |
0.47 |
0.18 |
0.28 |
0.37 |
0.35 |
0.088 |
0.278 |
|
40-60 |
0.27abcde |
0.49b |
0.21c |
0.17d |
0.61e |
0.090 |
0.024 |
|
60-80 |
0.50abcd |
0.28bcd |
0.23cd |
0.28d |
0.98e |
0.094 |
0.001 |
|
80-100 |
1.13acd |
0.65bc |
0.82cd |
1.07d |
1.99e |
0.090 |
0.001 |
|
0-100 |
0.48a |
0.35b |
0.32b |
0.37b |
0.77c |
0.024 |
0.001 |
|
Final weight (g) |
60.8 |
45.0 |
46.4 |
49.7 |
91.3 |
2.72 |
<0.001 |
|
#
CTL: Cook taro leaves,
DTL: Dry taro leaves, ETL: Ensiled taro leaves, FTL: Fresh taro
leaves, SB: Soybean |
|||||||
In figure 1 showed that the mean value of weight gain in every 20 days was not different among treatments during starting to 60 days of experiment but from 60 days toward, the weight gain was improved on SB and CTR treatment compared with DTR, ETR and FTR
|
|
|
Figure 1: Mean values of weight at 20 day intervals of catfish fed different form of taro leaves as protein source replacing soybean meal |
Length gains of catfish were start different from 60 days toward but in overall, the length gain was high on SB treatment (P<0.05) rather than treatment of taro leaves processing. The length in taro leaves processing treatment in this study were lower than reported of Nguyen Duy Quynh Tram et al (2007) who got (0.72mm) when hybrid catfish fed biodigester effluent but similar with SB (0.074cm) treatment in this study.
|
Table 5: Mean value of length gain of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment # |
|
|
||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Length gain, cm/day |
|
|
|
|
|
||
|
0-20 |
0.091 |
0.086 |
0.085 |
0.089 |
0.069 |
0.014 |
0.829 |
|
20-40 |
0.078 |
0.035 |
0.038 |
0.057 |
0.076 |
0.015 |
0.219 |
|
40-60 |
0.035 |
0.056 |
0.041 |
0.052 |
0.042 |
0.014 |
0.841 |
|
60-80 |
0.064ac |
0.062abc |
0.035ab |
0.029ab |
0.123c |
0.018 |
0.038 |
|
80-100 |
0.126ac |
0.046b |
0.057ab |
0.116a c |
0.142c |
0.017 |
0.009 |
|
0-100 |
0.065ac |
0.057a |
0.048b |
0.056abc |
0.074c |
0.003 |
0.006 |
|
Final length, cm |
18.0 |
15.6 |
15.8 |
16.5 |
19.2 |
0.45 |
0.001 |
|
#
CTL: Cook taro leaves,
DTL: Dry taro leaves, ETL: Ensiled taro leaves, FTL: Fresh taro
leaves, SB: Soybean |
|||||||
In overall, the ratio of weight and length gain were higher on SB treatment (P<0.001) rather than on taro leaves processing.
|
Table 6: Mean value of ratio of weight and length gain of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment # |
||||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Increase in weight/length, g/cm |
|
|
|
|
|||
|
0 |
0.88 |
0.87 |
1.01 |
0.83 |
0.87 |
0.068 |
0.401 |
|
20 |
1.14 |
1.12 |
1.24 |
1.05 |
1.10 |
0.089 |
0.657 |
|
40 |
1.70 |
1.33 |
1.61 |
1.52 |
1.51 |
0.149 |
0.523 |
|
60 |
1.99 |
1.95 |
1.82 |
1.65 |
2.30 |
0.166 |
0.152 |
|
80 |
2.47a |
2.16a |
2.05a |
1.99a |
3.16b |
0.131 |
0.001 |
|
100 |
3.37a |
2.87b |
2.94b |
3.02ab |
4.77c |
0.101 |
0.001 |
|
#
CTL: Cook taro leaves,
DTL: Dry taro leaves, ETL: Ensiled taro leaves, FTL: Fresh taro
leaves, SB: Soybean |
|||||||
In overall, fish survival was not different among treatment and taro leaves processing (P>0.05). The mean fish survival rate ranged from 93.3-100% which showed high survival rate than study of Nguyen Duy Quynh Tram et al (2007) who got 84.9-85.2% on the hybrid catfish. The high fish survival rate in this study due to in this experiment, fish were culture in concrete pond compared with Nguyen Duy Quynh Tram et al (2007) who culture in natural pond and big pond size.
|
Table 7: Mean value of survival of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment # |
||||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Total initial fish # |
15 |
15 |
15 |
15 |
15 |
- |
- |
|
Total finale fish # |
14.7 |
14.7 |
15.0 |
14.0 |
15.0 |
0.333 |
0.274 |
|
Survive rate, % |
97.8 |
97.8 |
100 |
93.3 |
100 |
2.22 |
0.274 |
|
# CTL: Cook taro leaves, DTL: Dry taro leaves, ETL: Ensiled taro leaves, FTL: Fresh taro leaves, SB: Soybean |
|||||||
There were significant differences among treatments on fish yield, with highest values for SB (2472kg/ha) and CTL (1514kg/ha) treatment but lowest was DTL (1058kg/ha), ETL (1064kg/ha) and FTL (1150kg/ha) (P<0.001).
|
Table 8: Mean value of yield of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment # |
||||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Total initial weight, g |
133.4 |
129.4 |
163.2 |
119.6 |
132.5 |
14.8 |
0.362 |
|
Total finale weight, g |
890.5a |
658.2b |
695.5b |
694.4b |
1368.8c |
35.3 |
0.001 |
|
Net weight gain, g/pond |
757.1a |
528.8b |
532.3b |
574.8b |
1236.2c |
32.8 |
0.001 |
|
Total net weight gain, kg/ha |
1514.2a |
1057.6b |
1064.6b |
1149.6b |
2472.4c |
65.7 |
0.001 |
|
#
CTL: Cook taro leaves,
DTL: Dry taro leaves, ETL: Ensiled taro leaves, FTL: Fresh taro
leaves, SB: Soybean |
|||||||
During the experiment, water parameter were measured (Table 9) and are shown that the water temperature ranged from 29.4-29.9 0C in the morning, 32.2-33.20C in the afternoon and 31.6-32.80C in the evening but those values did not significant different on times and treatments (P>0.05). pH value ranged from 6.80-7.06 in the morning and 7.14-7.47 in the evening but those value did not significant different (P>0.05). Dissolved oxygen ranged from 1.75-3.42 in the morning and 4.00-5.00 mg/liter in the evening but those value were not significant different (P>0.05). In term of water transparency ranged from 14.7-28.1cm but significant different (P=0.042) which was lowed on ETL (14.7cm) treatment but other treatments were not different. The water parameter in this study were ranged with study of Nguyen Duy Quynh Tram et al (2007) who showed that water temperature ranged from 20-300C, pH ranged from 6.0-9.5 and dissolved oxygen 1.5-7.0mg/litre. Chhay Ty et al (2011) un published data study on effect of protein-rich foliage and fertilizer from pig manure or biodigester effluent on growth of Tilapia (Oreochromis niloticus) and Silver Carp (Hypophthalmichthys molitrix) showed similar data with present study (temperature: 28.3-32.3, pH: 7.45-7.58, DO: 0.5-5.89 mg/l) but low in water transparency (11.1-12.4cm) than in present study.
|
Table 9: Mean value of water parameter of catfish fed different form of taro leaves as protein sources replacement for soybean meal in concrete ponds |
|||||||
|
|
Treatment # |
||||||
|
CTL |
DTL |
ETL |
FTL |
SB |
SEM |
Prob |
|
|
Temperature, 0C |
|
|
|
|
|
|
|
|
Morning |
29.6 |
29.9 |
29.4 |
29.8 |
29.8 |
0.25 |
0.689 |
|
Afternoon |
32.8 |
32.7 |
32.4 |
32.6 |
33.2 |
0.39 |
0.686 |
|
Evening |
32.4 |
32.3 |
32.0 |
31.6 |
32.8 |
0.42 |
0.317 |
|
pH |
|
|
|
|
|
|
|
|
Morning |
6.80 |
6.83 |
6.92 |
6.83 |
7.06 |
0.11 |
0.502 |
|
Evening |
7.21 |
7.14 |
7.43 |
7.24 |
7.47 |
0.12 |
0.314 |
|
Dissolved oxygen, mg/litre |
|
|
|
|
|
|
|
|
Morning |
1.92 |
2.75 |
1.75 |
3.42 |
2.58 |
0.56 |
0.247 |
|
Evening |
4.67 |
4.67 |
5.00 |
4.00 |
4.17 |
0.66 |
0.820 |
|
Water transparency, cm |
|
|
|
|
|
||
|
Afternoon |
19.0abcde |
24.7bcde |
14.7cd |
23.0de |
28.1e |
3.19 |
0.042 |
|
#
CTL: Cook taro leaves,
DTL: Dry taro leaves, ETL: Ensiled taro leaves, FTL: Fresh taro
leaves, SB: Soybean |
|||||||
It is concluded that taro leaves can be used successfully for growing catfish by supplementing them with agriculture by-product. The specific conclusions were:
Daily weight gain was highest on soybean and cooked taro leaves diet but lowest on dried, ensiled and fresh taro leaves diet.
Length gain and ratio of weight and length were highest on soybean diet but not different on taro leaves processing.
Fish survival was not different in all diets.
Fish yield was highest values for soybean and cooked taro leaves but not different on dried, ensiled and fresh taro leaves diet
Water parameter did not different among diets but water transparency was lowed on ensiled taro leaves diet but other treatments were not effect
The authors would like to express the gratitude to the MEKARN project financed by the SIDA-SAREC Agency and to the Center for Livestock and Agriculture Development (CelAgrid), for providing resources for conducting this experiment.
AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15th edition (K Helrick editor). Arlington pp 1230
Chhay Ty, Khieu Borin and Preston T R 2010. Effect of Taro (Colocasia esculenta) leaf+stem silage and mulberry leaf silage on digestibility and N retention of growing pigs fed a basal diet of rice bran. Livestock Research for Rural Development. Volume 22, Article #109. http://www.lrrd.org/lrrd22/6/chha22109.htm
Du Thank Hang and Preston T R 2010. Effect of processing taro leaves on oxalate concentration and using the ensiled leaves as a protein source in pig diets in central Vietnam. Livestock Research for Rural Development. Volume 22, Article #68. http://www.lrrd.org/lrrd22/4/hang22068.htm
FAO 2005. FAO fishery country profile. The kingdom of Cambodia
Hang D T and Preston T R 2009. Taro (Colocacia esculenta) leaves as protein source for growing pig in central Vietnam. Livestock Research for Rural Development. Volume 21, Article #164. Retrieved October 20, 2010, from http://www.lrrd.org/lrrd21/10/hang21164.htm
MTAB 2007 Minitab reference Manual release 15.1.2. User’s guide to statistics. Minitab Inc., USA
Nguyen Duy Quynh Tram, Le Duc Ngoan and Ogle B 2007: Effect of processing pig manure through a biodigester as fertilizer for fish ponds on water quality and growth performance of three fish species. Master thesis 2005-2007 http://www.mekarn.org/msc2003-05/theses05/tram_p1.pdf
Pets and animals 2009. Pangasius catfish. http//www.ayushveda.com/blogs/pets/pangasius-catfish-2/#more-2550
Pham Sy Tiep, Nguyen Van Luc, Trinh Quang Tuyen, Nguyen Manh Hung and Tran Van Tu 2006: Study on the use of Alocasia macrorrhiza (roots and leaves) in diets for crossbred growing pigs under mountainous village conditions in northern Vietnam. Workshop-seminar "Forages for Pigs and Rabbits" MEKARN-CelAgrid, Phnom Penh, Cambodia, 22-24 August, 2006. Article # 11. Retrieved July 15, 109, from http://www.mekarn.org/proprf/tiep.htm.htm
Rodríguez Lylian, Peniche Irina, Preston T R and Peters K 2009a: Nutritive value for pigs of New Cocoyam (Xanthosoma sagittifolium); digestibility and nitrogen balance with different proportions of fresh leaves and soybean meal in a basal diet of sugar cane juice. Livestock Research for Rural Development. Volume 21, Article #16. http://www.lrrd.org/lrrd21/1/rodr21016.htm
Rodríguez Lylian, Preston T R and Peters K 2009b: Studies on the nutritive value for pigs of New Cocoyam (Xanthosoma sagittifolium); digestibility and nitrogen balance with different levels of ensiled leaves in a basal diet of sugar cane juice. Livestock Research for Rural Development. Volume 21, Article #27. http://www.lrrd.org/lrrd21/2/rodr21027.htm
Undersander D, Mertens D R and Theix N 1993 Forage analysis procedures. National Forage Testing Association. Omaha pp 154.
