Survey on the supply and use of feed in farming giant freshwater prawn, pangasius and snakehead fish in the Mekong Delta

Feeding amount of 500 - 650 tons/ha/crop is suitable and brings high economic efficiency.

Pangasius farming time from 5 to 6 months is highly effective in terms of economy and technique. Increasing farming time does not bring high efficiency because it requires more feed, increasing feed conversion ratio (FCR). On the other hand, increasing farming time increases fish size, making it difficult to sell because processing plants only buy fish with small size. Harvesting early or late does not bring high economic efficiency, so raising fish from 5 to 6 months when the fish reach commercial size is the best time to harvest (Figure 4.17b).

1400

1200

1000

800

600

400

5000

4000

3000

2000

200

<350 tons/ha

350-500 tons/ha

500-650 tons/ha

> 650 tons/ha

Yield/vu (tan/ha) Profit/vu (tr.d/ha)

1000

4-5 months

5-6 months

6-7 months

Yield/vu (tan/ha) Profit/vu (tr.d/ha)

Figure 4.17a;b: Effects of feed amount and harvest time on yield and profit of Pangasius fish

4.5.3. Multivariate correlation of productivity and profit of snakehead fish farming model

The results of multivariate correlation analysis show that 5 factors affect the productivity and profit of the snakehead fish farming model. Among the factors affecting productivity, the amount of TATS is the strongest factor, followed by the frequency of water change, water change rate and harvest size (Table 4.11). Regarding profit, TATS, harvest size and water change rate are the 3 most influential factors (Table 4.12).

Table 4.11: Factors affecting productivity of snakehead fish

Influencing variables	B	Std. Err	Beta	t	Sig.t
(Constant)	40.06	20.28		1.97	0.05
X 1 : Frequency of water change (time/day)	1.06	0.35	0.14	2.99	0.00
X 2 : Average water change rate (%/time)	-0.32	0.11	-0.13	-2.95	0.00
X 3 : Harvest size b. mass (head/kg)	-6.55	3.26	-0.09	-2.00	0.05
X 4 : Fresh food/m2/crop (kg)	0.28	0.01	0.92	20.55	0.00
X 5 : Harvest time (days)	-0.16	0.13	-0.05	-1.21	0.23
Correlation coefficient and significance level of the model RR 2 R 2 adjusted F F-sig.
multivariate correlation	0.96	0.93	0.92	102.98	0.00

Maybe you are interested!

Table 4.12: Factors affecting the profit of snakehead fish farming model

Influencing variables

B	Std. Err	Beta		t	Sig.t
(Constant)	1,026.7	424.94			2.42	0.02
X 1 : Average water change rate (%/time)	-3.82	1.95		-0.23	-1.96	0.06
X 2 : Harvest size b. mass (head/kg)	-127.01	62.88		-0.25	-2.02	0.05
X 3 : Fresh food/m2/crop (kg)	1.36	0.24		0.64	5.56	0.00
X 4 : Harvest time (days)	-3.61	2.52		-0.17	-1.43	0.16
X 5 : Size of the seed (cm/seed)	-32.15	26.52		-0.15	-1.21	0.23
Correlation coefficient and significance level of RR 2 R 2 adjusted F F-sig.
multivariate correlation model	0.70	0.49	0.42		7.61	0.00

The Effect of Water Change Frequency and Water Change Rate

With the snakehead fish farming model, mainly raising snakehead fish with nets, it is not necessary to change the water continuously every day. The appropriate water change frequency is from 5 to 7 days/time and each time change about 40 to 55% of the water in the pond (for snakehead fish nets placed in the pond) (Figure 4.18a and 4.18b). Snakehead fish eat fresh food, so the pond environment is quickly polluted by excess food. Changing too much or too little water is not good for the fish and the profit when harvesting.

500

400

300

200

100

300

200

100

Hang now

2-4 days/time

5-7 days/time

>8 days/time

NS/crop (kg/m2) LN/crop (000d/m2)

10-25%

25-40%

40-55%

>55%

NS/crop (kg/m2) LN/crop (000d/m2)

Figure 4.18a;b: Frequency and water change rate affect NS and LN of snakehead fish model

Figure 4.19a shows that the amount of TATS is proportional to the productivity of farmed snakehead fish and that households that feed snakehead fish from 250 - 350 kg of TATS bring the highest profit. When increasing the amount of TATS to over 350 kg/m 2 /crop, the profit tends to decrease but the productivity of farmed fish does not decrease. Increasing the amount of feed increases the cost of feed, so it is not economically effective. On the other hand, TATS is very easy to pollute the pond, not beneficial to the health of farmed fish, so increasing the amount of feed above the threshold of 350 kg/m 2 /crop is unnecessary.

Harvest size does not affect productivity much but has a strong impact on profit. To achieve the highest profit, snakehead fish should be harvested when they are 0.6 - 0.8 kg/fish. If the fish are allowed to grow larger, profits tend to decrease and decrease when the fish reach a size of 1 kg/fish (Figure 4.19b).

1000

800

600

400

300

200

NS/m2 (kg/m2)

100

NS/m2 (kg/m2)

<50 kg

150-250 kg

>350 kg

LN/m2 (000d/m2)

< 0.4 kg/head

0.6-0.8 kg/head

> 1.0 kg/piece

LN/m2 (000d/m2)

50-150 kg

250-350 kg

0.4-0.6 kg/head

0.8-1.0 kg/head

Figure 4.19a;b: Amount of TATS, harvest size affects the productivity and profit of snakehead fish farming

4.5.4. Effects of feed types on farming models

When considering the multivariate correlation between factors affecting the amount of feed used during the rearing process (Table 4.13), there are 6 factors affecting feed: (1) rearing time; (2) harvest time; (3) stocking density; (4) rearing area; (5) variables of the rearing model (D1, D2).

Stocking density is proportional to feed use. When increasing the density to 1 fish/m2 , the amount of feed must be increased to 937 kg/ha/crop. When increasing the level of intensification (increasing density), the amount of feed must be increased, so attention must be paid to the pond environment, technical and economic efficiency.

Table 4.13: Factors affecting food intake of farming models

Influencing variables	B	Std. Err	Beta	t	Sig.t
(Constant)	-14.03	7909		-0.17	0.85
X1: Incubation time (days)	-2.08	0.88	-0.13	-2.34	0.02
X2: Harvest time (days)	0.53	0.46	0.07	1.15	0.25
X3: Stocking density (fish/m2)	0.93	0.14	0.38	6.49	0.00
X4: Farming area (ha or m2)	-0.03	0.02	-0.07	-1.37	0.17
X5: D1 (1=Snakehead Fish, 0=other)	53.33	38.96	0.10	1.36	0.17
X6: D2 (1=Pangasius, 0=other)	459.36	38.27	0.74	12.00	0.00
Correlation coefficient and significance level RR 2 R 2 adjusted F F-sig.
of multivariate correlation model	0.89	0.80	0.78	70.15	0.00

On the contrary, the incubation time is inversely proportional to the amount of feed used. When the incubation time increases, the amount of feed used during the incubation process decreases. This shows that incubation before incubation can save on feed costs and reduce product prices.

The amount of feed used in the Pangasius farming model is much higher than the other models. When raising Pangasius, 459 tons/ha/crop must be used, which is an issue that needs attention when planning or investing in Pangasius farming. When planning the farming area

It is necessary to plan the raw material area to provide enough food during the farming process. For farmers who want to invest in raising Pangasius, they need to pay attention to the supply and transportation of food to ensure there is no interruption during farming.

4.6. Impact of feed use on food competition, environmental pollution and labor use

4.6.1. Competition for food for the community when using TS food

Table 4.14 shows that most households using feed in the Tra fish farming model (100%) and TCX (50%) believe that the use of industrial feed does not affect the food source for the poor. Meanwhile, 25% of households believe that the use of a lot of feed as a food source for the poor has decreased sharply. Similarly, with TATS, 86.7% believe that it does not affect the food source for the poor and 13.3% of households believe that it has decreased but very little. The food source for the poor is believed to decrease sharply when using TATC for aquaculture (33.3% of households using).

Table 4.14: Impact of food types on food poverty reduction

Item

Unit	Snakehead Fish	Pangasius Fish	TCX	Total
1. With animal feed	n	0	6	4	10
- Reduced a lot	%			25.00	10.00
- No change	%		100.00	50.00	80.00
- Increase a lot	%			25.00	10.00
2. With TATS	n	10	0	5	15
- Reduce a little	%	10.00		20.00	13.30
- No change	%	90.00		80.00	86.70
3. With TATC	n	0	3	0	3
- Reduced a lot	%		33.30		33.30
- No change	%		66.70		66.70

4.6.2. Potential for environmental pollution when using aquatic feed

The use of animal feed has a significant impact on the environment (35.3% of households using animal feed) and 5.9% of households said that the use of animal feed has a significant impact on the environment. With animal feed, 35.0% of households assessed that it has a significant impact on the environment and 5.0% assessed that it has a very significant impact on the environment. This rate is higher in the group of households raising TCX (14.3% of households) and the significant impact on the environment was answered by 42.9% of households. With animal feed, 66.7% of households assessed that it has a significant impact on the environment. This is an issue that needs much attention, when developing farming areas such as increasing the area or increasing farming density, it causes environmental pollution. The problem of treating polluted water sources from aquaculture areas is an urgent issue and needs to be done immediately to limit negative impacts on the environment in the future.

Table 4.15: Impact of food types on environmental pollution potential

Item

Unit	Snakehead Fish	Pangasius Fish	TCX	Total
1. Animal feed impacts the environment	n	0	9	8	17
- So many	%			12.50	5.90
- Quite a lot	%		66.70		35.30
- Medium	%		33.30	25.00	29.40
- Little	%			25.00	11.80
- Very little	%			37.50	17.6
2. TATS impacts the environment	n	13	0	7	20
- So many	%			14.30	5.00
- Quite a lot	%	30.80		42.90	35.00
- Medium	%	30.80		14.30	25.00
- Little	%	30.80		28.60	30.00
- Very little	%	7.70			5.00
3. TATC impacts the environment	n	0	3	0	3
- Quite a lot	%		66.70		66.70
- Medium	%		33.30		33.30

4.6.3. Impact of food types on labor utilization

53.8% of households using feed said that after switching from TATC to TACN, labor was greatly reduced, and feeding and using feed did not require as much labor as before. On the contrary, 68.8% of households using TATS said that labor usage remained unchanged compared to before and 12.5% of households used more labor. Households using TATC increased labor during feeding but not much (66.7%).

Table 4.16: Impact of food types on labor utilization

Item

Unit	Snakehead Fish	Pangasius Fish	TCX	Total
1. With animal feed	n	0	6	7	13
- Reduced a lot	%		33.30	71.40	53.80
- Reduce a little	%		33.30		15.40
- No change	%		33.30	28.60	30.80
2. With TATS	n	11	0	5	16
- No change	%	81.80		40.00	68.80
- Increase slightly	%	9.10		40.00	18.80
- Increase a lot	%	9.10		20.00	12.50
3. With TATC	n	0	3	0	3
- No change	%		33.30		33.30
- Increase slightly	%		66.70		66.70

4.6.4. Some suggestions/solutions of households to limit the impact of food on the environment, food and labor use

Planning concentrated farming areas and having a schedule for changing water at the same time is the solution proposed by 100% of Tra fish farming households using feed. For snakehead fish farming households, planning concentrated farming areas to limit the negative impacts of feed on the environment, food competition and labor use was proposed by 63.6% of households. Meanwhile, households using feed in the Tra fish farming model proposed to monitor and adjust the daily feed amount appropriately, avoiding excess will reduce the negative impacts when using feed (75.0%) (Table 4.17).

Feeding enough or not enough food is suggested by many households raising Pangasius using TACN to improve the negative impact of food. This is also suggested by 28.6% of households raising Pangasius and is also the experience of raising Snakehead fish of 9.1% of households raising Snakehead fish. This is an issue related to farming techniques that farmers need to pay attention to and implement, which will contribute to reducing environmental pollution in ponds and drainage canals (Table 4.17).

When the water environment in the pond is polluted, it is necessary to use probiotics or biological products to treat it. This issue was proposed by 57.1% of Tra fish farming households, 54.5% of Snakehead fish farming households and 33.3% of TCX farming households to overcome the pollution situation (Table 4.17).

Table 4.17: Solutions to reduce negative impacts when using aquatic feed

Snakehead			Look up
1. Solutions to reduce impact on animal feed	n		7	3	10
- Should concentrate on farming areas, change water simultaneously	%		100		70.00
- Feeding enough or not enough is better	%		28.60	100	50.00
- Use probiotics and biological products for treatment	%		57.10	33.30	50.00
- Monitor and adjust daily TA intake accordingly	%		42.90	33.30	40.00
2. Solutions to reduce impact on TATS	n	11		4	15
- Should concentrate on farming areas, change water simultaneously	%	63.60		25.00	53.30
- Use probiotics and biological products for treatment	%	54.50			40.00
- Monitor and adjust daily TA intake accordingly	%	9.10		100.0	33.30
- Feed fresh TATS, reduce trash fish	%	18.20		75.00	33.30
- Feeding enough or not enough is better	%	9.10			6.70
3. Solutions to reduce impact on TATC	n		4		4
- Monitor and adjust daily TA intake accordingly	%		75.00		75.00
- Use probiotics and biological products for treatment	%		25.00		25.00

Item Unit Fish TCX Total

5.1. Conclusion

CHAPTER V

CONCLUSION AND SUGGESTIONS

From the results of surveys, statistics and analysis of the situation of feed use in freshwater aquaculture, the following basic conclusions can be drawn:

(1) Agents supplying and trading feed for aquaculture annually sell an average of 1,656 tons, the highest is 6,000 tons and the lowest is 300 tons of feed. Feed prices fluctuate between 5,990 - 7,000 VND/kg. With aquatic feed processing factories producing an average of 44,000 tons/year and the feed price sold from the factory to agents and farmers fluctuates between 5,000 - 6,780 VND/kg.

(2) The Pangasius farming model uses an average of 409±268 tons of feed/ha/crop. With the TCX farming model, the average amount of feed used is 23,830 kg/ha/crop, of which the most is OBV 21,366 kg (89.7% of total feed), followed by feed 2,020 kg (8.5%), freshwater trash fish 364 kg (1.5%) and marine trash fish 80 kg (0.3%). In the Snakehead fish farming model, to raise 1m2 of Snakehead fish in a net, farmers must use 166±120 kg of Pangasius and Basa fish by-products/crop, 115±159 kg of marine trash fish/crop and 126±116 kg of freshwater trash fish/crop.

(3) The amount of feed is proportional to the productivity of the Pangasius farming model. However, at the time of the survey, the amount of feed from 500 - 650 tons/ha/crop was suitable and effective. The farming time of 5 - 6 months was highly effective economically. Harvesting earlier or later did not bring high economic efficiency.

(4) The Pangasius farming model using mainly feed has the lowest feed conversion ratio (FCR) (1.75±072), the Snakehead fish farming model (100% TATS) has an FCR of (3.49±0.65) and the TCX has the highest FCR of (12.53±11.10).

(5) 25% of households believe that the use of animal feed as a food source for the poor has decreased significantly. With the use of animal feed, 13.3% of households believe that there is a reduction in food for the poor, but the reduction is very small. The food source for the poor has decreased most when using animal feed (33.3% of households use it).

(6) The use of animal feed has a significant impact on the environment (35.3% of households using animal feed) and 5.9% of households believe that the use of animal feed has a significant impact on the environment. Meanwhile, 53.8% of households using animal feed believe that after switching from animal feed to animal feed, labor is greatly reduced, and feeding and using food does not require as much labor as before.

Survey on the supply and use of feed in farming giant freshwater prawn, pangasius and snakehead fish in the Mekong Delta - 8

Comment