With the aim of determining the best technique to ensile chicken manure as animal feed, a completely randomized design with 9 treatments was used to evaluate a basal mixture of chicken manure and rice bran (40 and 35%, respectively in DM), plus 25, 20, 15, 10 and 5% of cassava root meal and sugar cane molasses at levels of 0, 5, 10, 15 and 20%. In the remaining 4 treatments, the sugar cane molasses was replaced with cassava root residue.
After 7 days of ensiling the pH value fell to below 5 and remained at 4.0 to 4.6 until 90 days in every treatment. There was a decrease in pathogen concentration after 7 days and elimination after 14 days.
A feeding trial was conducted with growing pigs in 3 households in Dong Anh district, Hanoi City with 4 treatments: Control (concentrate only), and diets with 25, 50 and 75% (of DM) of the concentrate replaced with chicken manure silage (40% chicken manure, 35% rice bran and 25% cassava root meal, in DM).
Growth rate of the pigs from 15 to 50 kg live weight decreased (410 falling to 349 g/day) as the level of chicken manure silage was increased. However, from 50 to 70 kg, there were no differences among the treatments (range from 560 to 525 g/day). Overall, the growth rate and DM feed conversion became worse, and back fat thickness decreased, as the level of chicken manure silage was increased. Pathogen (E. coli and Salmonella) concentrations were found to be around 1 cell/g meat in all treatments, which is considered safe for human consumption.
Traditionally, animal excreta generally and chicken excreta, in particular, are applied to farmland as fertilizer. However, it has been shown that animal excreta may be more valuable as animal feed than as fertilizer (Arndt et al 1979) due to their high nutritive value, especially the nitrogen content. Fontenot (1980) showed that broiler litter used as fertilizer had a value of only 26.54 USD per ton, whereas its value was much higher (160 USD per ton) when it was used as animal feed. In addition its use can create systems of mutually complementing integration of animal production among individual species, which can in turn solve some of the problems of waste disposal and pollution.
In the north of Vietnam chickens are commonly raised by two methods: on the floor with bedding (deep litter) and in cages (without bedding). In the latter case, the chicken manure appears to be more valuable for use as a protein feed resource for pigs, replacing scarce and expensive conventional protein sources. Furthermore, one important current problem of Vietnamese poultry farmers is how to re-use chicken manure and litter as feed for other animals in order to reduce environmental pollution and improve incomes.
Ninh Thi Len (2001) indicated that sun-dried chicken manure can be used as a protein source to replace groundnut cake in diets for F1 pigs. However, processing it by sun-drying depends on the weather and needs high inputs of labour. In the conditions of Vietnam, with a high humidity and rainfall, sun-drying chicken manure is often difficult, so ensiling would appear to be a more suitable method to process and preserve the manure. Using ensiled chicken manure in the diet would also decrease feed investment for farmers.
The objectives of this research were:
The hypotheses were:
Ensiling chicken manure with rice bran, cassava root meal, cassava residue and sugar cane molasses can be an acceptable method for processing and preserving chicken manure as a protein feed resource for fattening pigs under small-holder conditions
Chicken manure silage is palatable and digestible for F1 growing pigs
Replacement
of the traditional diet with chicken manure silage for pigs can give adequate
growth performance and will be cheaper and more economical under village
conditions.
The experiment was conducted in the laboratory of the Department of Animal Nutrition, NIAH.
The experimental design was a completely randomized comparison of 9 treatments (Table 1). The fresh chicken manure (CM) was collected from a farm, in which broilers are kept in cages. After 3 days of collection, the fresh chicken manure was mixed with the rice bran (RB), cassava root meal (CRM), and cassava residue or sugar cane molasses (SCM). The mixtures were then put into plastic bags, sealed and stored at room temperature (25 to 30 ºC).
|
Table 1.
Ingredient composition of the silage mixtures
|
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|
|
Molasses |
|
|||||||
|
|
0 |
5 |
10 |
15 |
20 |
5 |
10 |
15 |
20 |
|
Chicken manure |
40 |
40 |
40 |
40 |
40 |
40 |
40 |
40 |
40 |
|
Rice bran |
35 |
35 |
35 |
35 |
35 |
35 |
35 |
35 |
35 |
|
Cassava root meal |
25 |
20 |
15 |
10 |
5 |
20 |
15 |
10 |
5 |
|
Molasses |
0 |
5 |
10 |
15 |
20 |
0 |
0 |
0 |
0 |
|
Cassava residue |
0
|
0 |
0 |
0 |
0 |
5 |
10 |
15 |
20 |
Samples of the silage were taken at: 0, 7, 14, 21, 28, and 56 days after ensiling to determine:
Dry matter (DM), crude protein (CP), true protein (TP) and ammonia (NH3).
Fermentation characteristics: pH
Physical characteristics: Color, smell.
Hygiene characteristics: E coli and Salmonella concentrations
The
experiment was conducted in Nguyen khe village, Dong anh district, Hanoi.
The experimental design was a completely randomized block with forty eight F1 crossbred pigs (Mong Cai x Yorkshire) with initial body weights of 12 to 15 kg were divided amongst 3 farms, with 16 pigs per farm and each farm as a block. The pigs in each farm were allocated randomly into 4 pens, with 4 pigs per pen (2 females and 2 castrate males) and each pen representing a treatment (Table 2).
|
Table 2.
Experimental design of the feeding trial |
||||
|
|
CM-0 |
CM-25 |
CM-50 |
CM-75 |
|
Number of pigs |
12 |
12 |
12 |
12 |
|
Number of farms |
3 |
3 |
3 |
3 |
|
CM silage in diet, % in DM |
0 |
25 |
50 |
75 |
Fresh chicken manure was collected from broiler cages every 5 days and mixed with rice bran and cassava root meal in proportions of 40 CM, 35 RB and 25 CRM (% in DM). The mixture then was put into 30 kg nylon bags and sealed to avoid air contamination. After 21 days of ensiling, the silage was mixed with a concentrate (control diet) before being fed to the pigs (Tables 3 and 4). The experimental diets were formulated to meet requirements for growing (15-50 kg) and finishing pigs (>50 kg).
|
Table 3. Ingredient and chenmical composition of the basal (CM-0) diets (as fed basis), Experiment 2. |
||
|
|
Growing period |
Finishing period |
|
Maize |
52.75 |
57.25 |
|
Rice bran |
25.0 |
30.0 |
|
Ground nut cake |
15.0 |
10.0 |
|
Fish meal |
6.0 |
2.0 |
|
Vit-min premix |
0.25 |
0.25 |
|
Salt |
0.5 |
0.5 |
|
Limestone |
0.5 |
0.5 |
|
Chemical composition |
||
|
ME (kcal/kg) |
3000 |
2980 |
|
Crude protein (%) |
16.2 |
13.2 |
|
Crude fibre (%) |
5.1 |
5.3 |
|
Ca (%) |
1.3 |
1.2 |
|
P (%) |
0.5 |
0.4 |
|
Table 4. Chemical composition of diets (% in DM) |
|||
|
|
CM-25 |
CM-50 |
CM-75 |
|
|
Growing period |
||
|
Crude protein |
17.5 |
17.5 |
17.6 |
|
True protein |
14.1 |
12.4 |
11.4 |
|
Crude fibre |
7.61 |
7.93 |
8.52 |
|
Ca |
1.52 |
1.78 |
2.12 |
|
P |
0.51 |
0.61 |
0.71 |
|
|
Finishing period |
||
|
Crude protein |
15.5 |
15.8 |
16.4 |
|
True protein |
11.5 |
10.5 |
10.1 |
|
Crude fibre |
7.89 |
8.14 |
9.31 |
|
Ca |
1.51 |
1.51 |
2.11 |
|
P |
0.47 |
0.52 |
0.58 |
All the diets
were given ad libitum. Feed offered
and feed refusals were recorded daily. At
the beginning and at the end of each feeding period the pigs were weighed in the
morning before feeding. Fifteen days before slaughter all pigs were taken off
the diets containing chicken manure in order to ensure safe, hygienic quality of
the meat. When the pigs reached a body weight of around 70 kg, 2 representative
pigs (one male and one female) on each treatment were slaughtered. Parameters
determined were:
Daily feed intake
Average daily gain
Feed conversion ratio and economical efficiency
Dressing percentage, back fat thickness, quality of meat in terms of concentrations of pathogenic bacteria (E coli and Salmonella)
The data were analyzed using the GLM procedure in
MINITAB software, version 11.2.
The DM contents in the silage mixtures with high levels of cassava root meal were the highest, followed by the silages with molasses and then cassava residue, due to the fact that the initial DM content in cassava root meal was higher than in molasses and cassava residue (Table 5). However, within silages (treatments) the dry matter content did not change with time of ensiling. True protein was estimated to be about 70% of the crude protein and did not differ among treatments.
|
Table 5. Dry matter of ingredients before ensiling (%) |
|
|
|
% |
|
Chicken manure |
35 |
|
Rice bran |
87 |
|
Cassava root meal |
87 |
|
Molasses |
61 |
|
Cassava residue |
19 |
The pH value of all silage mixtures was around 6.5 at day 0, and after 7 days fell to below 5.0, and then remained at 4.0 to 4.6 until 90 days. It can be concluded that the all the silage mixtures can be stored for at least 90 days. As the pH decreased, pathogen concentrations also decreased quickly. After 14 days of ensiling, all E coli and Salmonella bacteria in the silage were destroyed. Therefore the silage mixtures are considered safe to feed to animals after 14 days of ensiling. It is concluded that proper ensiling of animal waste appears to be effective in destroying pathogens as long as pH is in the range 4.0 to 4.5 and the temperature is over 250C, which is necessary for the destruction of salmonella.
Experiment 2
At the end of Period 1 (growing period), the final weights and growth rates were inversely related to the level of ensiled chicken manure (Table 6). The explanation is probably that the young pigs could not digest the high-fibre CM very efficiently, and also that the true protein content was lower and/or protein quality possibly poorer in the diets with chicken manure silage. However, in Period 2 this trend changed, with apparently faster growth in pigs fed the diets with highest concentrations of chicken manure silage. It is likely that the older, heavier pigs in Period 2 could digest the fibre in chicken manure more efficiently. Overall, however, growth rates decreased slightly as the chicken manure silage was increased in the diet These findings are similar to the results of Ninh Thi Len (2001) in a study where sun-dried chicken manure replaced groundnut cake in the diet.
|
Table 6. Mean values for change in live weight of the pigs fed diets with increasing proportions of chicken manure silage |
|||||
|
|
CM-0 |
CM-25 |
CM-50 |
CM-75 |
Prob. |
|
15-50 kg, 75 days |
|
|
|
||
|
Initial LW, kg |
16.8 |
16.7 |
16.4 |
16.3 |
0.98 |
|
Final LW, kg |
50.5a |
47.1b |
43.5c |
42.5c |
0.002 |
|
Daily gain, g |
450a |
410b |
361c |
349c |
0.000 |
|
50-70 kg, 40 days |
|
|
|
||
|
Initial LW, kg |
50.5 |
47.1 |
43.5 |
42.5 |
|
|
Final LW, kg |
71.5 |
69.3 |
66.1 |
64.9 |
0.13 |
|
Daily gain, g |
525a |
558ab |
565b |
560b |
0.04 |
|
Overall |
|
|
|
|
|
|
Daily gain, g |
476a |
458ab |
432ab |
423b |
0.04 |
|
ab Mean values within rows without common letter are different at P<0.05 |
|||||
Feed intake increased with increase in the level of chicken manure silage in the diet, which together with the lower growth rate resulted in poorer feed conversion, especially in Period 1 (Table 7). These results, which are to be expected in view of the lower energy density and poorer protein quality in ensiled chicken manure, compared with concentrates, nevertheless are in contrast with those of Quian et al (1994) and Diaz et al (1996) who concluded that adding chicken manure to pig diets improved growth and feed conversion rates and FCR compared to a control diet. Nguyen Thi Tinh and Tran Thanh Thuy (2000) also indicated that using chicken litter ensiled with sweet potato vines in pig diets improved growth rate and feed conversion.
|
Table 7. Mean values for feed DM intake and feed DM conversion ratio of the pigs fed diets with increasing proportions of chicken manure silage |
|||||
|
|
CM-0 |
CM-25 |
CM-50 |
CM-75 |
Prob. |
|
15-50 kg |
|
|
|||
|
Concentrate, kg |
1.41 |
1.17 |
0.74 |
0.41 |
|
|
CMS, kg |
0 |
0.37 |
0.75 |
1.22 |
|
|
Total DMI, kg |
1.41a |
1.54ab |
1.49ab |
1.63b |
0.019 |
|
FCR, kg/kg |
3.13a |
3.77b |
4.12c |
4.67d |
0.011 |
|
50-70kg |
|
|
|||
|
Concentrate, kg |
2.18 |
1.69 |
1.23 |
0.62 |
|
|
CMS (kg) |
0 |
0.61 |
1.23 |
2.13 |
|
|
Total DMI, kg |
2.18a |
2.3ab |
2.46b |
2.75c |
0.015 |
|
FCR, kg/kg |
4.15a |
4.13ab |
4.35b |
4.91c |
0.003 |
|
Overall |
|
|
|||
|
Concentrate (kg) |
1.68 |
1.35 |
0.91 |
0.48 |
|
|
CMS (kg) |
0.00 |
0.45 |
0.92 |
1.54 |
|
|
Total DMI, kg |
1.68a |
1.80ab |
1.83ab |
2.02b |
|
|
FCR, kg/kg |
3.53a |
3.94b |
4.23c |
4.78d |
0.037 |
|
Feed cost* /kg LWG |
10 568 |
10 585 |
9 995 |
9 752 |
|
|
* VND: 1US $ =
15,000 VND |
|||||
Despite the poorer performance, economic efficiency was increased by substitution of concentrates with ensiled chicken manure, due to the lower cost of this feed component. In cases where chicken manure is available on the farm including it in pig diets would reduce feed costs even more. Nguyen Thi Tinh and Tran Thanh Thuy (2000) also concluded that using sweet potato vine ensiled with chicken manure for F1 pigs considerably reduced feed costs and resulted in higher net profits for the farmers.
There was no difference in carcass percentage between
treatments (Table 8). However, as the level of chicken manure silage in the diets increased,
the back fat thickness decreased. This is probably due to the decrease in dietary
energy density reflecting the low digestibility of chicken
manure. Using chicken manure in animal diets is a concern of some producers
because of fears that pathogens from the manure could affect meat
hygienic quality. However in the present study E coli and Salmonella
completely disappeared after 21 days of ensiling, and therefore their presence in meat was
eliminated (Table 8). Very small E coli
concentrations were found in meat from pigs from the control and high CM diet,
probably because of contamination.
|
Table 8. Mean values for carcass percentage (%), back fat thickness and pathogen levels in carcasses of F1 fattening pigs fed diets with increasing proportions of chicken manure silage |
|||||
|
|
CM 0 |
CM 25 |
CM 50 |
CM 75 |
Prob. |
|
Carcass percentage |
78.8 |
80.2 |
80.4 |
79.1 |
0.51 |
|
Fat thickness (cm) |
2.51a |
2.32a |
1.93b |
1.67c |
0.007 |
|
E coli (No./g) |
1.2 |
- |
- |
0.6 |
|
|
Salmonella (No./g) |
Neg |
Neg |
Neg |
Neg |
|
Chicken
manure can be ensiled at level of 40% (in DM) with rice bran, cassava root
meal, molasses and cassava residue and preserved for at least 2 months for use
as animal feed.
The
level of inclusion of chicken manure silage should be no more than 25 – 50% of
the diet for pigs of 20 to 50 kg, and 75 % of the diet for pigs of 50-70 kg.
At
current feed prices replacement of up to 75% of concentrate feed by chicken
manure silage considerably improves the economic efficiency of F1 fattening pig
production.
Including
chicken manure silage in fattening pig diets reduced fat percentage and did not
negatively affect meat quality in terms of pathogen concentrations in meat,
provided that the silage was withdrawn 15 days before slaughter.
Arndt D L, Day D L and Hatfield E E 1979 Processing and handling of animal wastes. Journal of Animal Science 48, 157-162.
Diaz J, Elias
A and Achan J 1996
A note of the study of Vitafert (sugarcane
+ poultry manure) levels in
pre-fattening pigs. Cuban Journal of Agricultural Science, 30 (3), 301-303.
Fontenot
J P 1981 Recycling of Animal Wastes by Feeding. New Protein Foods. Academic Press, Inc.
pp 277-304.
Ninh
Thi Len 2001
Effect of replacing groundnut cake by
chicken manure in diets containing ensiled cassava
residue on digestibility and growth performance of fattening F1 pigs. MSc thesis.
Nguyen Thi Tinh and Tran Thanh Thuy 2000 Improved feed for pig raising in Vietnam. Urban Agriculture Magazine 1, 37-38
Quin Y, Xu D, Sun Z and Tang Y L 1994
Experiments on feeding pigs and fish on
Vo Thi Kim Thanh
1999 Ensiling groundnut leaves as feed for pigs. In Sustainable Livestock