| Workshop-seminar, 23-25 May, 2005, MEKARN-CTU |
| Contents |
A trial was conducted in the dry season in 2004 at the Experimental Poultry Farm of Cantho University in the Mekong Delta of Vietnam to evaluate techniques for the production of termites and fly larvae, and the effects of using these as protein supplements in maize-based diets of growing local chicks. The experiment included three treatments with four replicates and five chicks per group: chicks confined and fed a commercial mash control diet (CTr); chicks confined and given a diet based on maize offered ad libitum and supplemented with 1.8 g of DM/day of fresh termites (FTE); confined and given a diet based on maize offered ad libitum and supplemented with 2.1g of DM/day of fresh fly larva (FFL). These diets were offered to the chicks from 10 to 31 days of age.
Total daily intakes (g
DM) were 28.7, 27.9 and 28.3 and daily live
weight gains 9.1, 9.0 and 10.9 g/day for CTr, FTE and
FFL, respectively. Corresponding feed conversion ratios were 3.2, 2.9 and
2.4 kg feed/kg gain, respectively .
Raising local poultry is a traditional activity for many farmers
in the Mekong Delta of Vietnam (Men 1996). There are several
alternative systems practiced, the most profitable being releasing
young, growing chicks to scavenge for insects, worms and grasses in
the gardens of households. However, because of the recent outbreaks
of Avian Influenza in the Mekong Delta, there is pressure on the
farmers (disease prevention regulations) to keep their flocks in
confinement in order to reduce the risk of infection spreading.
Most producers in fact want to increase the number and productivity
of their flocks by confining them, but this is difficult because of
limited areas of land for buildings and the high cost of protein
feeds. As a result the profit margins are often low. At present,
prices of protein feeds such as soybean meal and fish meal
fluctuate, but generally are 20 to 50% higher compared to 2002, and
amounts available are declining.
Possible cheap alternative protein supplements
include termites and fly larvae. These can be grown on bagasse from
sugar plants or waste wood from silk cotton trees and animal
manure, which are waste materials with a very low value in the
Mekong Delta. Studies from several other countries showed that
producing termites and larvae to feed to chickens gave good results
(Viet Chuong 2001).
Two experiments were carried out, firstly to evaluate using bagasse or waste wood to produce termites, and manure of pigs or cattle to produce fly larvae, and secondly to evaluate these as protein supplements for local chickens reared on-farm.
The
hypothesis of the experiment is that fly larvae and termites
offered restrictedly, together with maize meal supplied ad
libitum, can replace a commercial concentrate without reducing
growth performance in growing local chicks, and leading to
increased economic benefits.
The experiment was carried out at the Experimental Poultry Farm
of Cantho University in the Mekong Delta from December to March
2004.
Shallow 50x50x20 cm holes were dug around the
termite mounds, under the shade of trees. Then the holes were
filled with bagasse, tied tightly in bundles, and dry wood of
silk-cotton trees (around seven kg in total), and then covered with
jute sacks to keep the holes dark and humid. To maintain humidity
2-3 liters of water were sprinkled over the jute sacks. The
termites were harvested after 3 weeks by quickly opening the sack
covers, then collecting the bagasse together with the termites.
They were separated from the bagasse and wood by hand and kept in
plastic basins before being offered to the chicks.
Cartons were filled with bagasse and wood from
silk-cotton trees. Termite nests, containing whole families, were
collected from several different sites, divided into three to four
pieces, and put inside the boxes together with bagasse or wood. The
cartons were tightly closed to keep the insides of the boxes damp
and dark and sheltered from rain and direct sunlight. After 3 to
3.5 weeks the termites were harvested and offered to the chicks.
Rectangular holes, 50 x 50
cm and 70 cm deep, were dug and were filled with soft, damp rice
straw and fresh cattle manure in alternate 15cm thick layers. A
thin layer of rice gruel was placed on the top straw layer. Around
one kg of spoilt fish was added to attract flies to lay their eggs,
and small shelters were constructed over the holes to protect them
from rain and direct sunlight, and and to allow the flies to enter
the hole easily. To maintain high humidity 2-3 litres of water were
poured over the holes when the eggs had been laid. Growing larvae
were harvested 4-5 days after putting the bait into the
holes.
Fresh pig manure was collected
twice daily, and put into piles under the shade of trees near to
the pig farm. Small colored nylon sheets were placed on the
surface of the manure piles to keep the humidity high and reduce
the spread of the smell of the material. Natural fly species were
attracted by the fresh manure smell and laid their eggs. Growing
larvae were harvested five days later after removing the surface
manure layer.
Open rectangular boxes were
constructed from wood or fibro-cement and placed on the ground
under the shade of trees. The boxes were 50x100cm and 50 cm high. A
layer of rice straw was placed in the bottom of each box and then
the boxes were filled with fresh pig manure collected twice daily.
Waste water from a fish shop was collected and 3-4 litres sprinkled
over each box to keep humidity high and to attract natural fly
species to lay their eggs. Growing fly larvae were harvested five
days later after the first observation of the
larvae.
A total of sixty 10-day-old local chicks were brooded and
selected (from 100 chicks) from breeding flocks hatched at the
experimental hatchery of Cantho University. The chicks were brooded
in wire cages in groups consisting of five males and females. The
groups were allocated at random to three treatments, with four
replicates and five birds per replicate.
The chicks were housed in wire cages in a shed made from
concrete poles and bamboo frames, with thatched roofs and concrete
floor. Average density was 0.05 m2 of wire floor per
chick. The temperature in the house averaged 25.5°C
and relative humidity averaged 71.5% in the morning (8:00h),
28.8°C and 73.2% at noon (12:00h), and
25.3°C and 84.2% at night (22:00h). Natural light
was used in the day time and light from electric bulbs for lighting
and brooding, with an intensity of 5W/ m2 to maintain a
total of 24 hours light each day. Feeders used for the experiment
were round plastic feeders 20 cm in diameter. Drinkers were round
plastic bowls 15 cm in diameter.
During the brooding stage the chicks were fed commercial crumbs
ad libitum up to 10 days of age and then fed the
experimental grower diets. The chicks in the control treatment were
offered a commercial diet that consisted of 51.6% maize meal, 13%
rice bran, 21.3% roasted soya bean, 14.2% fish meal and 0.25%
vitamin-mineral premix. Feed ingredients were purchased in one
batch only and stored at room temperature on the farm and checked
daily.
Fresh termites were harvested twice daily during the
experimental period. Before the morning meal the termites raised in
the holes or boxes were collected by separating them from the
bagasse and wood and weighing them before offering them to the
chicks
Fresh larvae were harvested twice daily at the same time as the
termites. First, the surface manure layers were removed until the
larvae were exposed. Then the larvae were collected, cleaned with
water, drained and weighed before being fed to the
chicks.
The chicks fed the diets with fresh termites or larvae were
offered maize meal ad libitum, and the fresh termites and
larvae were offered twice daily, in the morning and afternoon.
Parameters measured included weights of termites and larvae
produced and growth and feed conversion of the chicks. Nutrient
composition of the diets and economic benefits were
calculated.
The samples of maize, rice bran, roasted
soybean, fresh termites and fly larvae were analysed for dry matter
(DM), crude protein (N x 6.25), crude fibre, ether extract,
nitrogen free extract and ash by standard AOAC methods (AOAC 2000). Metabolizable energy (ME) contents of the
diets were calculated from chemical analysis data using the
equation of Nehring and Haenlein (1973):
ME (kcal/kg) = 4.26X1 +
9.5X2 + 4.23X3 +
4.23X4.
The calculated digestible protein,
digestible fat, digestible fiber and digestible nitrogen-free
extractives (g/kg feed) are represented by X1 through
X4, respectively. Estimated digestibility coefficients
are according to NIAH (1992). Data were analysed by analysis of variance
using the General Linear Models procedure of Minitab, Version
13 (Minitab, 2000).
With around seven kg of bagasse and
cotton-tree wood as substrate for the termites an average 97g of
fresh termites were harvested during a 3-week period in the dry
season. This was enough to supplement 15 chicks at 20 days of age.
This method entails a risk of damage by ants and small
centipedes.
Termites feeding on bagasse or wood
in cartons grew better than those cultivated according to method 1,
due to better conditions and protection from damage. Around 133 g
of fresh termites were harvested per box during the 21-day period.
Yields of larvae harvested after the
5-day period were very low. This method is not suitable for
producing fly larvae under these particular experimental
conditions.
The use of fresh pig manure collected
into 50 kg piles to entice flies and to feed fly larvae was shown
to be an efficient method. After a 5-day period during the dry
season yields were around 160 g of fresh larvae per manure pile. If
fresh manure was added daily the larva yields were even
higher.
This technique was shown to be the
most effective in enticing different fly species (mainly houseflies
and bluebottles) to lay their eggs. Besides fresh manure, the
addition of fish waste attracted more flies, as well as supplying
more nutrients. The larvae yields were around 210 g per manure box
after the 5-day period. Environmental conditions influenced the
number of eggs laid and the growth rates of the larvae, as on the
days with light sunshine and breeze the manure boxes contained more
fly eggs and larvae.
The fresh termites (FTE) and fly larvae used in the experiment had an average DM content of 21.0 % and 26.5%, respectively. The nutrient concentrations (DM basis) are shown in Table 1. The crude protein (CP) contents (70.1% and 59.0% of DM, in the FTE and fly larvae respectively) were higher than in the roasted soya bean meal and fish meal used in the trial (43.1% and 29.7%, respectively), due to the fact that the termites and larvae used in our trial were grown on farm and were fresh. Metabolizable energy (ME) concentration of the larvae (17.5 MJ/kg) was higher than of the whole soya bean meal (16.3 MJ/kg of DM). However, the macro- and micro-mineral concentrations in the termite and larva samples were lower (8.26% and 6.62%, respectively) than those of fish meal (41.7%).
|
Table 1. Chemical composition of the feed ingredients used in the experiment |
||||||||
|
|
DM, % |
On DM basis, % |
||||||
|
CP |
EE |
NFE |
Crude fibre |
Ash |
ME, MJ/kg |
|||
|
Maize meal |
85.9 |
8.2 |
4.5 |
82.7 |
2.4 |
1.9 |
16.0 |
|
|
Rice bran |
90.0 |
13.5 |
12.7 |
58.5 |
7.6 |
7.7 |
12.6 |
|
|
Soya bean |
91.0 |
43.1 |
15.4 |
32.6 |
4.1 |
4.8 |
16.3 |
|
|
Fish meal |
81.3 |
29.7 |
4.4 |
18.1 |
6.0 |
41.7 |
8.5 |
|
|
Fresh termites |
21.0 |
70.1 |
7.0 |
1.2 |
13.5 |
8.3 |
14.1 |
|
|
Fresh larvae |
26.5 |
59.0 |
23.0 |
2.62 |
8.7 |
6.6 |
17.5 |
|
The maize meal offered was consumed readily on both the FTE and FFL treatments The amount of fresh termites and larvae was restricted, and total DM intakes were not different among treatments (Table 2). There were no differences in total ME intake, which was consistent with the reports on growing ducklings of Siregar et al (1982) and Dean (1986), who showed that ducks, like other food producing fowl, have a remarkable ability to adjust their feed intake so that their ME consumption is relatively constant, and is independent of both the concentration of dietary ME and protein (Zakaria 1992).
|
Table 2. Daily DM intakes of ingredients by local growing chicks |
||||
|
|
CTr |
FTE |
FFL |
P-value |
|
Mash or maize intake, g |
28.7a |
26.0b |
26.2 a b |
0.035 |
|
Termite or larvae intake, g |
- |
1.9 |
2.1 |
- |
|
Total DM intake, g |
28.7 |
27.9 |
28.3 |
0.686 |
|
Daily ME intake, MJ |
0.42 |
0.44 |
0.46 |
0.071 |
|
Daily CP intake, g |
5.6a |
3.5b |
3.4b |
0.001 |
|
CP/ME, g/MJ |
13.5a |
7.8b |
7.4b |
0.001 |
|
ab Means in same row without a common letter are different at P<0.05 |
||||
The rates of live weight gain were higher on the FFL diet (Table 3) compared to the CTr and FTE diets. However, calculated intakes of crude protein of the chicks on the control diet were higher than for the FTE and FFL diets. Crude protein intake per kg of live weight gain on treatment FFL was lower than on the control treatment, but daily gains were higher, possibly because the diet containing the larvae had a better balance of amino acids than the other two diets. DM feed conversion ratio was best on the larvae diet, and the chicks on the FFL diet also consumed less ME per kg of gain.
|
Table 3. Daily weight gains and feed conversion ratios of chicks |
||||
|
|
CTr |
FTE |
FFL |
P-value |
|
Live weight, g |
|
|
|
|
|
Initial |
92.2 |
92.7 |
96.6 |
0.271 |
|
Final |
284a |
281a |
326b |
0.001 |
|
Daily live weight gain, g |
9.1a |
9.0a |
10.9b |
0.001 |
|
FCR, kg DM / kg gain |
3.2a |
3.1a |
2.6b |
0.007 |
|
CP/kg gain, g |
617a |
388b |
309c |
0.001 |
|
ME/gain, MJ / kg |
45.9a b |
49.7a |
41.7b |
0.024 |
|
abc Means in same row without a common letter are different at P<0.05 |
||||
The results of the economic analysis are given in Table 4. The data show that the lowest feed cost per kg live weight gain was for the FFL diet, in which the protein supplement was completely replaced by protein from fresh larvae. There would thus appear to be economic benefits to the farmer from using fresh larvae to replace commercial diets for growing chicks, particularly in situations where the larvae are produced on the farm from fresh manure of pigs or poultry, and using household labour. This emphasises the importance of an integrated farming system as a means of reducing costs and improving the economic competitiveness of the small-scale farmer.
|
Table 4. Estimates of feed costs, assuming a situation of farm-based production of larvae and termites |
|||
|
|
CTr |
FTE |
FFL |
|
Feed cost*/kg gain |
15,403 |
9,181 |
7,546 |
|
* Based on price in VND per kg: maize meal 2,700; rice bran 2,500; roasted soya bean 6,500; fish meal 7,000 and premix 40,000. 15,760 VND=1US$ |
|||
Fresh termites can be produced from waste bagasse or dry
silk-cotton tree wood. A 3-week period of growing termites using
these materials in cartons produced the highest yield of termites.
The maximum yield of fly larvae was obtained by
using fresh pig manure in a time of only 4-6 days.
Termites and larvae were very palatable and can
completely replace roasted soya beans, fish meal and a vitamin
premix in maize meal based diets for growing local chicks without
reduction in growth performance.
Complete replacement of the protein supplement by
fresh termites or fly larvae produced on farm from waste bagasse,
wood or fresh pigs manure, and managed and harvested by household
labour, decreased the feed costs by 40% and 51%, respectively,
compared to the control diet,
This study was carried out at Cantho University, Vietnam. The
authors are grateful to the Swedish International Development
Authority (SIDA), Department for Research Co-operation (SAREC) for
financial support of the study.
The authors would also like to thank Cantho
University for allowing the use of their facilities, and research
assistants Dat and Cuong for their valuable help.
AOAC 2000 Official Methods of Analysis. Association of
Official Analytical Chemists, Washington, DC.
Bui Xuan Men Ogle B and Preston T R 1996 Duckweed
(Lemna spp) as replacement for roasted soya beans in diets
of broken rice for fattening ducks on a small scale farm in the
Mekong Delta. Livestock Research for Rural Development (8) 3:
14-19.
Dean W F 1986 Nutrient requirements of meat type ducks.
Duck Production Science and World Practice. Farell, D. J. and P.
Stapleton (Ed). University of New England, pp.31-57.
Le Thanh Hai, Nguyen Huu Tinh and Le Hong Dung 1995
Techniques of raising scavenging chickens. Agricultural Publishing
House. Ho Chi Minh City. pp 56-57.
Minitab Reference Manual 2000
Release 13 for Windows, Mintab Inc. USA.
National Institute of Animal Husbandry (NIAH) 1992 Feed
for Poultry. Composition and Nutritive Value of Animal Feeds in
Vietnam. Agricultural Publishing House, Hanoi. pp.140-188.
Nehring K and Haenlein G F W 1973 Feed evaluation and
ration calculations based on net energy. Journal of Animal Science
36, 949-964.
Project VIE/97/P11 2000 How to raise chicken to get high
effects. 36 p. Hanoi.
Siregar A P, Cumming R B and Farrell D J
1982 The nutrition of meat-type ducks. II the effects of
variation in the energy and protein contents of diets on biological
performance and carcass characteristics. Australian Journal of
Agricultural Research 33: 365-375.
Viet Chuong 2001 Production of larvae and earthworms to
feed farm animals. HoChi Minh Publishing House. pp. 47-68.
Zakaria A 1992 Advances on feeding and management of ducks in Indonesia. Sustainable Animal Production. Proceedings of the sixth AAAP Animal Science Congress, Vol. II. AHAT, Bangkok. pp.47-53.