Livestock Research for Rural Development

Volume 9 Number 1

Chemical composition of cashew apple and cashew apple waste ensiled with poultry litter

 

La Van Kinh, Vu Van Do and Dang Duc Phuong

Institute of Agricultural Sciences, Ho Chi Minh City, Vietnam

Abstract

The aims of this study were to examine the possibility of using whole cashew apple and cashew apple waste (a residue from fruit processing) as feed for dairy cows by ensiling them with poultry litter. The basic material was either the waste` (after juice extraction) or the whole cashew apple. Four treatments (combinations with poultry litter) with each product were compared. as follows: 100% cashew apple waste (CAW) or cashew apple (CA), 90% CAW (or CA) +10% poultry litter (PL), 80% CAW (or CA) + 20% PL and 70% CAW (or CA) + 30% PL based on fresh weight. The materials were ensiled in glass jars (2.5 litres capacity). There were 3 replications (jars) of each treatment of whole fruit and waste and of each of the sampling times, which were at 0, 3, 7, 15 and 30 days after ensiling.

 The pH fell rapidly in the first three days and continued to fall until the 7th day to a constant value of around 4.45. Total sugars also were reduced dramatically in the first three days (from 12.2 to 1.9% in DM). The sensory evaluation showed that the silages from 100% CAW or 90% CAW and 10% PL were of acceptable quality (yellow colour, nice smell) and those from 80% and 70% CAW were not acceptable (dark colour, bad odour).

 It is concluded that cashew apple fruit and cashew apple waste (after juice extraction) can be preserved for long term use by anaerobic ensiling and that there appeared to be little advantage in mixing them with poultry litter before ensiling. The conversion of the soluble sugars into organic acids and alcohol may have negative effects on nutritive value. Feeding trials are necessary to evaluate this.

Key words: Cashew apple fruit, waste, ensiling, composition


Introduction

Vietnam needs to develop its dairy cow population and milk production but feed shortage is one of the main constraints. Traditional feeds are expensive and agroindustrial by-products such as brewery grains have been exploited and exhausted. Cashew apple (Anacardium occidentale) is a promising feed source, which could be used for dairy cows. In 1995, the whole country had 200,000 ha of cashew trees. From this area, about 500,000 tons of cashew apple will be produced per year. There is commercial interest in processing the fresh apple as a source of sugar-rich juice for human consumption. The waste product from processing, after drying, has been fed to pigs and poultry with promising results (La Van Kinh unpublished observations). The problem is that it is uneconomical to dry the cashew apple or the waste product after juice extraction, and it is more appropriate to develop methods to use it in wet form. This was the rationale for the present study.

Because of the high content of water-soluble carbohydrates - the main substrate for lactic fermentation - and the low content of crude protein (low buffering capacity), it was hypothesized that the cashew apple, and the waste product, should be ensiled with poultry litter. Poultry litter has good buffering capacity and a high content of NPN as uric acid. The idea to use poultry litter was based on experiences with other sugar-rich feeds such as citrus and pineapple pulps and ground sugar cane. The dry poultry litter helped to raise the dry matter of the ensiled product and, by providing fermentable nitrogen (as uric acid) and minerals, helped to encourage the growth of lactic acid bacteria rather than alcohol-forming yeast (Preston T R unpublished observations).

 
The hypotheses to be tested were that:

The ensiling process relies on the fermentation to produce lactic acid. A good silage is one with minimum dry matter losses, lactic acid as not more than 60% of total acid and acetic acid not exceeding 2.5 % of the dry matter and butyric acid less than 0.5 %in dry matter.


Materials and methods

Feeds

Cashew apple waste (CAW) was brought from a factory processing cashew apples to extract the juice. The poultry litter (PL) was from a State farm where laying birds were housed on deep litter. The composition of these feed resources was determined by standard methods (AOAC 1988) and is shown in Table 1.


Experimental design

There were 4 treatments applied to each of the basic materials of CA and CAW, consisting of mixtures of CA or CAW and PL (% fresh basis). Separate jars (capacity 2.5 litres) were filled for each of five sampling times (0, 3, 7, 10, 15 and 30 days) with three replications of each treatment/time combination.

The treatments were:

Cashew apple waste

CAW100: CAW with no additive

CAW90: 90CAW + 10PL

CAW80: 80CAW + 20PL

CAW70: 70CAW + 30PL


Cashew apple

The treatments were the same as for CAW but using CA.


Method of ensiling in the laboratory and sampling

CAW or CA was mixed with PL, put into a jar (2.5 litres capacity) and compressed to expel all the air and the jars closed with an air-tight lid.


Measurements

The fermentation characteristics were determined by the following parameters:


Method of evaluation of silage quality (based on INRA standard)

The proposed parameters are set out in Table 1.

 

Table 1: Evaluation of silage quality according to INRA Standard

Evaluation

Acetic acid, % in DM

Butyric acid, % in DM

Soluble N, % of total N

N-NH3, % of total N

Excellent

<2.0

0

< 50

< 5

Very good

2.0 - 4.0

< 0.5

50 - 60

7 - 10

Good

4.0 - 5.5

> 0.5

60 - 65

10 - 15

Bad

5.5 - 7.5

> 0.5

65 - 75

15 - 20

Very bad

> 7.5

> 0. 5

> 75

> 20

 

Results and Discussion

The detailed analytical data for all combinations of cashew apple waste (or cashew apple) and poultry litter with time of ensiling are in Annex Tables 1 and 2. The sensory characteristics are in Table 3. The trends for pH with time of ensiling for all combinations of cashew apple waste and poultry litter are in Figure 1. Figures 2, 3 and 4 show data for the zero and 10% poultry litter level for total sugars, lactic acid and soluble N as percentage of total N in the cashew apple waste silages. .

 

Table 2: Chemical composition of cashew apple waste (CAW) and of poultry litter (PL)  

CAW

CA

PL

Dry matter, %

22.5

12.37

86.5

Content in DM, %      
N*6.25

13.7

12.5

17.5

Crude fibre

11.8

3.54

15.8

Ash

1.4

1.62

22.34

Calcium

0.25

0.03

3.32

Phosphorus

0.34

0.07

1.66

Total sugars

26.5

54.7

Nd

Soluble N, % total N

10.9

25.6

26.7

N-NH3 ,% total N

1.82

2.07

7.14

PH

4.1

4.00

Nd

Nd Not determined      

The only silages that could be considered to be acceptable on the basis of colour and smell were those with zero and 10% poultry litter (Table 3). The trends for pH showed clearly that with more than 10% poultry litter the final pH was too high to ensure satisfactory preservation. However, this situation was not reflected in the levels of soluble N or in the organic acid concentrations (Figures 3 and 4). The former was high (20-30%) on all combinations of CAW and PL while the latter were all in the normal range.

The sugar content fell dramatically in all silages within 3 days of beginning the ensiling process as can be seen in Figures 2 and 5, which show results for the 100/0 and 90/10 CAW/PL and CA/PL combinations. More than one third of the sugars was fermented to ethanol for the CA silages and presumably the same occurred with the CAW silages. Adding poultry litter to the whole cashew fruit reduced the concentrations of ethanol but did not preserve the sugars (Annex table 2).

 
Conclusions

 

Acknowledgement

We would like to express many thanks to the International Foundation for Science for financial support to the senior author (Grant No: B/2433) to carry out this project.

 
References

AOAC 1988 Official Methods of Chemical Analysis. Association of Official Agricultural Chemists. Washington DC (4th edition)

 

 

                       
Annex Table 1: Mean values for composition of silage according to level of addition of poultry litter and duration of ensiling (values are on % DM basis except for soluble N and NH3-N which are as % of total N)
Item Day DM CP Sugar pH Lactic Lactic, % total acid Acetic Butyric Soluble N NH3-N
100 % CAW
  0 22.52 13.73 26.50 4.1 2.75 89.87 0.31 0 10.92 1.82
  3 21.97 13.62 2.17 4.0 1.95 52.21 1.69 0.12 19.04 2.98
  7 21.63 13.66 1.99 4.1 4.02 64.42 2.10 0.12 25.36 4.95
  15 21.72 13.45 1.50 4.0 4.82 48.26 5.33 0.03 21.85 8.78
  30 22.02 13.9 0.67 4.0 2.86 54.76 2.26 0.10 21.23 7.68
90 % CAW + 10% PL
  0 29 14.2 18.86 5.0 2.44 92.78 0.19 0 34.99 8.54
  3 29 14.05 3.12 4.0 1.91 83.30 0.31 0.08 28.05 10.23
  7 28.75 14.1 2.59 4.0 3.09 63.66 1.61 0.14 21.80 9.52
  15 28.75 14.0 2.37 3.9 8.06 81.13 1.71 0.15 31.28 10.48
  30 28.75 14.15 1.15 4.0 7.56 67.27 3.51 0.14 28.27 9.73
80% CAW +20% PL
  0 35.5 14.7 16.12 5.9 1.62 68.35 0.75 0 30.57 9.95
  3 35.25 14.8 0.97 4.7 1.17 56.39 0.73 0.18 30.29 12.25
  7 34.5 14.0 1.63 4.7 4.21 79.40 1.02 0.07 30.14 11.74
  15 35.0 14.45 1.45 4.7 3.73 66.59 1.75 0.13 31.17 11.14
  30 34.5 14.7 1.02 4.6 4.38 59.75 2.89 0.13 28.62 6.46
70% CAW +30 % PL
  0 41.6 15.0 3.70 6.7 1.58 62.20 0.96 0 31.25 10.29
  3 41.1 14.75 1.34 5.6 0.71 40.42 0.96 0.07 30.08 11.66
  7 41.45 14.75 1.14 5.2 3.59 63.67 1.97 0.08 29.63 14.22
  15 41.65 14.9 0.84 5.3 3.02 69.70 1.19 0.12 28.09 11.95
  30 41.1 15.15 0.81 5.2 3.97 53.12 3.27 0.24 28.22 5.94

 

 

                                 
Annex Table 2: Mean values for composition of silage from whole cashew apple fruit according to level of addition of poultry litter and duration of ensiling (values are on %DM basis except for soluble N and NH3-N which are as % of total N)
Day DM CP Sugar pH Lactic Lactic, % total acid Acetic Butyric Ethanol Soluble-N N-NH3 Ash
100% CA
0 12.37 12.50 54.7 4.0 5.00 95.57 0.23     25.62 2.07 1.62
3 12.27 12.19 35.7 3.6 11.25 70.07 4.28 0.42   29.41 1.93 3.33
7 12.70 12.40 26.9 3.5 13.31 75.74 4.24 0.03 13.89 18.74 3.29 3.2
15 12.21 12.38 10.5 3.5 12.69 76.90 3.80 0.01 15.78 25.98 4.72 3.48
30 12.37 12.41 8.6 3.5 19.49 64.71 10.57 0.05 17.65 26.31 2.53 3.22
90% CA + 10% PL
0 20.27 13.38 31.0 4.8 3.06 93.04 0.23         6.78
3 19.83 13.10 18.0 4.0 15.46 74.45 5.52 0.04   28.45 3.62 6.78
7 19.97 13.07 16.8 3.9 16.15 73.01 5.93 0.03 8.21 32.47 3.45 9.41
15 20.12 13.03 3.2 4.0 9.62 73.94 3.33 0.08 7.06 38.63 11.6 8.51
30 20.15 13.17 1.7 4.1 11.55 58.99 7.77 0.21 7.17 32.39 11.4 8.27
80% CA + 20% PL
0 27.12 13.70 20.6 5.6 2.69 85.06 0.48         10.83
3 27.19 13.40 6.4 4.2 10.39 78.26 2.87 0.03   33.32 7.96 10.36
7 27.23 13.37 5.6 4.1 13.87 81.45 2.88 0.28 1.14 36.67 7.51 10.35
15 27.28 13.63 2.0 4.1 9.03 68.86 4.06 0.15 3.08 37.32 12.9 9.54
30 26.93 13.33 1.7 4.3 10.54 60.20 6.96 0.08 9.11 39.31 16.1 10.02
70% CA + 30% PL
0 34.34 14.00 13.8 5.9 2.35 75.17 0.78         13.07
3 34.21 14.20 7.1 4.5 8.82 76.49 2.73 0.03   38.38 10.9 13.07
7 34.26 14.47 4.9 4.6 10.29 70.52 4.16 0.1 2.26 36.48 8.89 12.73
15 34.24 14.30 1.6 4.6 7.2 71.74 2.66 0.1 1.96 39.94 12.6 10.99
30 34.32 14.37 0.6 4.5 9.72 60.94 6.16 0.1 6.00 42.79 13.6 11.5

 

Received 1 October 1996