Advertisement

Nutritional potentials and in vitro estimation of composite cocoa pod husk-based diets for ruminants

  • Oluwatosin Bode OmotosoEmail author
Open Access
Research

Abstract

Background

The use of cocoa pod husk in livestock nutrition is being limited because of its fibrous nature and anti-nutrients, which have detrimental effect(s) on the animals. This study was conducted to evaluate the nutritive value and effects of replacing urea-treated ensiled cocoa pod husk meal (urea-treated CPHM) with cassava peel in a complete concentrate diet (CCD) on in vitro digestibility and methane (CH4) production.

Methods

Urea-treated CPHM was prepared by soaking the raw milled pod in 5% urea solution under anaerobic condition for 7 days, and decanted and the filtrates were further ensiled for 28 days, dried, and were replaced with cassava peel meal in CCD at 0, 5, 7.5, 10, 12.5, and 15% on part basis. Feed samples (n = 3) were analyzed for chemical composition, and data generated from in vitro study were subjected to statistical analysis in a completely randomized design experiment.

Results

Results revealed that the treatment significantly reduced the crude fiber, fiber fraction contents, and anti-nutrients and improved the crude protein content of the pod by 71.84%. Dry matter and crude protein of the diets ranged from 89.34–89.71% and 10.52–12.84%, respectively. The in vitro dry matter digestibility (IVDMD) increased with increasing levels of urea-treated CPHM in the diets. With increasing levels of urea-treated CPHM, CH4 production relatively reduced as compared to diet E. Metabolizable energy (5.66 Kcal/g) of diet F was the highest. Therefore, the inclusion of urea-treated CPHM at 15% in CCDs has the potential for improving digestibility and reducing CH4 production in ruminants.

Keywords

Cocoa pod husk Methane Ruminant Urea treatment 

Introduction

Livestock production is undertaken in a multitude of ways across the planet, providing a large variety of goods and services, using different animal species and different sets of resources, in a wide spectrum of agro-ecological and socio-economic conditions (Steinfeld et al., 2006). In recent years, emphases have been shifted to the use of by-products of agro-industrial origin as low-cost alternative carbohydrate sources for livestock nutrition. Sucharita et al. (1998) concluded that effective utilization of non-conventional feeds should be the major areas of research in the less developed countries due to shortage of conventional feedstuffs, ever-increasing human population and to ensure their food security, which is dependent on the better utilization of alternative feed resources. Though ruminant animals can thrive very well on fibrous feeds to keep their rumen healthy, but higher quantities of cellulose, hemicellulose in the cell wall and presence of anti-nutritional factors usually limit efficient nutrients utilization by the ruminants (Makkar, 1993).

Consequently, cocoa pod husk which is an abundant residue generated on cocoa farmlands has been regarded as a “waste” in Nigeria, except for the negligible amount used in the manufacture of local soap. It has however been reported to contain about 80.00–88.96% DM, 6.00–9.14% CP, 24.93–35.74% CF, and 14.10–21.16% lignin (Aregheore, 2002; Ozung et al., 2016). To nutritionally upgrade the crop residue for efficient utilization by ruminant animals, urea, a non-protein nitrogen, which can be easily converted to ammonia in the rumen, could be effective.

Thus, an in vitro study was conducted to evaluate the nutritive value and effects of incorporating graded levels of urea-treated ensiled cocoa pod husk meal in total mixed rations on digestibility and methane production.

Materials and methods

Experimental site

The study was carried out at the Nutrition Laboratory of the Animal Production and Health, Federal University of Technology, Akure (FUTA), located on latitude 7° 15′′ N and longitude 5° 15′′ E (Ajibade et al., 2014).

Sourcing and processing of feed materials

Cocoa pod husk was collected at various cocoa farmlands in Ilara-Mokin, Ondo State, sun-dried for 8–12 days, crushed at the FUTA feed mill to 1-mm particle size, and then soaked in the 5% urea solution under an anaerobic condition for 7 days. Thereafter, decanted and the filtrates were further ensiled for 28 days, dried, and were replaced with cassava peel meals at 0, 5, 7.5, 10, 12.5, and 15% in a complete concentrate diet (Table 1). The feed samples (n = 3) were analyzed for the chemical composition according to AOAC (2002) method.
Table 1

Gross composition of graded inclusion levels of urea-treated CPHM in complete concentrate diets

Diets/level of urea-treated CPHM replacement (%)

Ingredients (%)

0 (A)

5 (B)

7.5 (C)

10 (D)

12.5 (E)

15 (F)

Urea-treated CPHM

0.00

5.00

7.50

10.00

12.50

15.00

Cassava peels

50.00

45.00

42.50

40.00

37.50

35.00

Brewer dried grain

27.00

27.00

27.00

27.00

27.00

27.00

Wheat offal

5.00

5.00

5.00

5.00

5.00

5.00

Palm kernel cake

15.00

15.00

15.00

15.00

15.00

15.00

Bone meal

1.00

1.00

1.00

1.00

1.00

1.00

Salt

1.00

1.00

1.00

1.00

1.00

1.00

Premix

1.00

1.00

1.00

1.00

1.00

1.00

Total

100.00

100.00

100.00

100.00

100.00

100.00

In vitro degradability trial

Two adult male WAD goats of the same age and uniform conformation were selected as donors of rumen inoculum for in vitro studies. The animals were fed for 2 weeks with 40% concentrate feed and 60% Panicum maximum at 5% body weight. Rumen liquor was collected in the morning before feeding through a stomach tube against negative pressure created by a suction pump into the thermo-flask that had been pre-warmed to a temperature of 39 °C. Buffer solution prepared was the McDougall’s solution which consist solution (gram/liter) of 9.8 NaHCO3 + 2.77 Na2HPO4 + 0.57 KCl + 0.47 NaCl + 2.16 MgSO3.7H2O + 16 CaCl2.2H2O and mixed with rumen liquor at 1: 4 (v/v) under continuous flushing with CO2 to minimize changes in microbial populations and to avoid O2 contamination for the incubation. Incubation procedure was carried out using 120-ml calibrated transparent plastic syringes with a fitted silicon tube.

The sample weighing 200 mg (n = 3) was carefully dropped into syringes and thereafter 30 ml each of the inoculum containing cheesecloth strained rumen liquor and buffer solution. The syringe was tapped and pushed upward by the piston in order to completely eliminate air in the inoculum. The silicon tube fitted to the syringe was then tightened by a metal clip so as to prevent the escape of gas. Incubation was carried out at 39 ± 1 °C and the volume of gas production was measured at 3, 6, 9, 12, 15, 18, 21, and 24 h. At the end of the termination hour, 4 ml of NaOH (10M) was introduced to estimate the methane production according to Fievez et al., (2005), metabolizable energy (ME), organic matter digestibility (OMD), and short-chain fatty acids (SCFA) were estimated according to the methods of Menke and Steingass (1988). The average of the volume of gas produced from the blanks was deducted from the volume of gas produced per sample. The following were calculated as ME (MJ/KgDM) = 2.20 + 0.136GV + 0.057CP + 0.0029 CF; OMD (%) = 14.88 + 889GV + 0.45CP + 0.651XA; SCFA = 0.0239 V–0.0601. Where GV, CP, CF, and XA are total gas volume, crude protein, crude fiber, and ash, respectively.

Experimental design and statistical analysis

The experimental layout was completely randomized design and all data obtained were subjected to analysis of variance using SAS (2008), and the significant means were separated using Duncan Multiple Range Test of the same package (Duncan, 1955).

Results

Chemical composition (%) of raw CPHM, urea-treated CPHM, and formulated diets

Table 2 presents the chemical composition of raw CPHM, urea-treated CPHM, and replacement levels of urea-treated CPHM in the total mixed ration. The value of dry matter did not follow a particular trend. However, the values were not significantly (p > 0.05) varied. The highest DM (88.97%) was recorded for raw CPHM and least (89.34%) in treatment A (0% urea-treated CPHM). The crude protein (CP) value of the urea-treated CPHM increased by 71.84% over the raw CPHM, and this significantly (p < 0.05) influenced the CP contents of the diets. Consequently, the protein contents progressively increased with increased replacement levels of urea-treated CPHM in the complete concentrate diets. The highest CP (12.84%) was recorded for treatment F (15% urea-treated CPHM replacement level). The treatment effect caused the significant reduction in the crude fiber level, as 33.87% CF (raw CPHM) was reduced to 23.91% (urea-treated CPHM). Though, no significant reduction was noticed in the CF contents of the diets. The ether extract content values gradually increased across the treatment. Though, values recorded for treatment E and F were statistically (p > 0.05) similar. The highest EE (4.92%) and ash content (6.25%) values were obtained in raw CPHM, respectively. The value of nitrogen-free extract increased numerically from 35.62% (raw CPHM) to 41.81% (urea-treated CPHM).
Table 2

Chemical composition of raw, urea-treated ensiled cocoa pod husk and formulated diets

Diets/level of urea-treated CPHM replacement (%)

Parameters (%)

Raw CPHM

Urea-treated CPHM

0

A

5

B

7.5

C

10

D

12.5

E

15

F

SEM

Dry matter

88.97

89.87

89.34

89.41

89.39

89.64

89.71

89.64

0.52

Crude protein

8.31

14.28

10.52d

10.87d

11.35c

12.53b

12.67ab

12.84a

0.26

Crude fiber

33.87

23.91

17.29

17.32

17.37

17.36

17.32

17.31

1.77

Ether extract

4.92

3.82

2.33d

2.67c

3.07b

3.15a

3.17a

3.16a

0.22

Ash

6.25

6.05

5.47a

5.33ab

5.19b

5.11b

5.02c

5.01c

0.38

NFE

35.62

41.81

53.73a

53.22ab

52.40b

51.48b

51.47b

51.32b

1.34

NDF

63.23

52.64

73.90a

72.62ab

71.91b

70.68c

70.58c

69.13d

0.41

ADF

51.40

42.21

51.66a

49.62bc

50.83ab

49.13bc

49.59bc

48.42c

0.33

ADL

24.05

19.23

25.14a

23.37b

22.42b

23.17b

23.19b

22.48b

0.26

Calcium

0.41

0.51

0.54d

0.56cd

0.60c

0.66b

0.69ab

0.71a

0.02

Phosphorus

0.11

0.20

0.26d

0.28cd

0.29c

0.32b

0.34a

0.35a

0.01

Alkaloid

6.50

3.45

0.80a

1.49b

1.75c

2.00d

2.39e

2.81f

0.16

Theobromine

3.89

2.05

0.00a

0.77b

0.95c

1.12d

1.33e

1.47f

0.12

Means on the same row with different superscript letters are statistically (p < 0.05) different

A 0% replacement levels of urea-treated CPHM, B 5% replacement levels of urea-treated CPHM, C 7.5% replacement levels of urea-treated CPHM, D 10% replacement levels of urea-treated CPHM, E 12.5% replacement levels of urea-treated CPHM, F 15% replacement levels of urea-treated CPHM, NFE nitrogen-free extract, NDF neutral detergent fiber, ADF acid detergent fiber, ADL acid detergent lignin (n = 3)

The neutral detergent fiber and acid detergent fiber contents of raw cocoa pod husk were 63.23% and 51.40%, respectively, and higher compared to NDF (52.64%) and ADF (42.21%) of urea-treated CPHM. Similarly, the value of acid detergent lignin (24.05%) content of raw CPHM was the highest. The CPHM calcium and phosphorus concentrations varied positively with the treatment effect and significantly improved the Ca and P contents of the diets. The alkaloid and theobromine concentration of the pod drastically reduced, though the concentration increased with increased levels of urea-treated CPHM in the diets.

Table 3 presents the in vitro gas production of raw and replacement levels of cassava peels with urea-treated cocoa pod husk meal diets. The result showed that gas volume produced at different incubation time differed significantly (p < 0.05). The volume of gas produced increased with increasing incubation time (Fig. 1). The study revealed that raw CPHM produced the least gas volume (1.67 ml) at 3 h and highest (3.01 ml) at 18 h. However, gas production declined after 18th hour. Diet A (0% replacement level of urea-treated CPHM with cassava peels in the diet) produced the least volume of gas (3.33 ml) at 3 h of incubation time, while diet F produced the highest volume of gas (9.69 ml) under the same period of incubation. Gas volume production at 3 h was least in diet A (3.33 ml) and highest in diet F (9.69 ml). Similarly, at 24 h, the highest gas volume (20.19 ml) was obtained in diet F and least (10.67 ml) in diet A at 21 and 24 h.
Table 3

In vitro gas production of raw and replacement levels of urea-treated CPHM diets

Gas volume (ml)

Diets

3 h

6 h

9 h

12 h

15 h

18 h

21 h

24 h

Raw CPHM

1.67f

1.82e

1.99e

2.13e

2.47e

3.01f

2.89f

2.89f

A

3.33e

4.33d

6.33d

6.33d

8.33d

10.33e

10.67e

10.67e

B

4.67d

5.67c

6.67d

7.33d

9.67c

11.67d

11.93d

12.33d

C

6.00c

6.00c

8.00c

9.00c

11.00b

13.00c

14.00c

14.07c

D

8.33b

9.00b

11.00b

13.00b

16.33a

14.00b

17.67b

17.67b

E

9.67a

11.67a

14.33a

14.33a

16.33a

17.67a

20.00a

20.03a

F

9.69a

11.64a

14.29a

14.32a

16.34a

17.62a

20.01a

20.19a

SEM

0.66

0.81

1.00

1.06

1.13

1.15

1.08

0.97

Fig. 1

Graphical representation of in vitro gas production of raw and replacement levels of urea-treated cocoa pod husk meal diets

Means on the same row with different superscript letters are statistically (p < 0.05) different

CPHM cocoa pod husk meal, A 0% replacement levels of urea-treated CPHM, B 5% replacement levels of urea-treated CPHM, C 7.5% replacement levels of urea-treated CPHM, D 10% replacement levels of urea-treated CPHM, E 12.5% replacement levels of urea-treated CPHM, F 15% replacement levels of urea-treated CPHM

Presented in Table 4 are the in vitro characteristics of raw and replacement levels of urea-treated CPHM for cassava peels. The result showed a significant (p < 0.05) difference for all the parameters assessed with respect to the treatments. It was noted that the least values obtained in all the parameters assessed were for raw CPHM. However, the highest volume of methane gas (5.00 ml) produced was obtained in diets E and F, while the least was observed in diets A, B, and C (3.00 ml) which were numerically and statistically (p > 0.05) similar. The carbon dioxide (CO2) gas produced from the insoluble fraction increased with increased replacement levels of urea-treated CPHM for cassava peels in the diet. Diet F produced the highest volume of CO2 gas (15.19 ml), while diet A produced the least (7.67 ml). The organic matter digestibility (OMD) obtained ranged from 32.56% (diet A) to 41.37% (diet E). The short-chain fatty acid (SCFA) also increased with increased replacement of urea-treated cocoa pod husk meal for cassava peels in the diets; with the highest (0.42 μm) value obtained in diet F and least (0.19 μm) obtained in diet A. The metabolizable energy of the diets increased with increased replacement of urea-treated cocoa pod husk meal for cassava peels in the diets. Diets E and F had statistical (p > 0.05) similar values but differed numerically. The values of ME obtained ranged from 4.28 Kcal/g (diet A) to 5.66 Kcal/g (diet E). In vitro dry matter disappearance was highest (80.00%) in diets E and F and least (50.00%) in diet A.
Table 4

In vitro characteristics of raw and replacement levels of urea-treated CPHM diets

Diets

Methane (ml)

CO2 (ml)

OMD (%)

SCFA (μm)

ME (Kcal/g)

IVDMD (%)

Raw CPHM

1.00d

1.89e

25.26e

0.01e

3.16f

42.00c

A

3.00c

7.67d

32.56d

0.19d

4.28e

50.00bc

B

3.00c

9.33c

34.15c

0.23c

4.53d

60.06b

C

3.00c

11.07b

35.73c

0.28b

4.79c

60.06b

D

4.00b

13.67ab

38.98b

0.36a

5.29b

70.07a

E

5.00a

15.03a

41.13a

0.40a

5.63a

80.00a

F

5.00a

15.19a

41.37a

0.42a

5.66a

80.00a

SEM

0.29

2.09

0.94

0.02

0.14

3.01

Means on the same row with different superscript letters are significantly (p < 0.05) different

OMD organic matter digestibility, CO2 (carbon dioxide) gas production from insoluble fraction, SCFA short-chain fatty acid, ME metabolizable energy, IVDMD in vitro dry matter disappearance, CPHM cocoa pod husk meal, A 0% replacement levels of urea-treated CPHM, B 5% replacement levels of urea-treated CPHM, C 7.5% replacement levels of urea-treated CPHM, D 10% replacement levels of urea-treated CPHM, E 12.5% replacement levels of urea-treated CPHM, F 15% replacement levels of urea-treated CPHM

Discussion

The 88.97% DM, 8.31% CP, and 33.87% CF contents obtained for the raw CPHM in this study (Table 2) agreed with the reported values of about 80.00–88.96% DM, 6.00–9.14% CP, and 24.93–35.74% CF by Aregheore (2002) and Ozung et al., (2016). The dry matter of the pod before and after treatment (soaking in 5% urea solution for 7 days and ensiled for 28 days) and the formulated diets were high; this could be attributed to the dried nature of the pod and cassava peels, culminating in its high lignification. The CP content of the pod and invariably that of the diets was improved. The CP contents (10.52–12.84%) of the diets could adequately meet the protein requirement by ruminant animals for growth (NRC, 2007). The reduction in fiber contents could be as a result of the fermentation process during ensiling. The reduction in the alkaloid and theobromine might be traced to decanting after been soaked in urea solution and thus would make the feed more palatable to the animals. The amount of gas produced during fermentation is dependent on the nature, level of fiber, and potency of the rumen liquor used for the incubation. The result showed that gas volume produced at different incubation time differed significantly at p < 0.05.

The observed increase in the cumulative gas volume from 3 to 21 h (Table 3), and the gradual decline after 21 h of incubation from diets A to F could be associated to the replacement levels of urea-treated CPHM and thus predicted digestibility, fermentation end-product, and microbial protein synthesis of the diets by rumen microbes in the in vitro system. This also implied that digestion would take place within the normal rumen retention time at 21 to 24 h and could be an indirect measure of dry matter degradability. This trend agreed with the report of Babayemi and Bamikole (2006) when a similar method was used to evaluate the nutritive value of Tephrosia candida DC leaf and its mixtures with Guinea grass for ruminant feeding. From Table 4, methane gas produced was in line with the values reported by Okoruwa and Agbonlahor (2016) when they investigated the gas production characteristics of cocoa pod husk with soursop pulp meals used in replacement for Napier grass in the diet of WAD sheep. Thus, the methane gas volume produced in this study could be traced to the gradual increment in the protein quality of the diets.

The apparently low methane gas volume produced in this study is an indication of the effective utilization of the diets. The gradual increase in the value of OMD and ME reported implied a mutual relationship exists between total methane production and ME with OMD (Babayemi and Bamikole, 2006). The low SCFA reported in this study were due to the lower methane gas production which was evident within the 24-h incubation period. The increased value of IVDMD of urea-treated CPHM-based diets over the raw CPHM could be traced to the effect of soaking in urea solution because great quantities of cell contents were dissolved in the water. Thus, the formulated diets are rich in nutrients, highly digestible, and could meet the nutrient requirements for growth/maintenance by ruminant animals.

Conclusions

The study established that cocoa pod husk has nutritional potentials in ruminant nutrition and could be nutritionally upgraded by soaking in 5% urea solution for 7 days, ensiled for 28 days, and incorporated up to 15% replacement level in the ruminants’ diets. However, in vivo study should be carried out to substantiate the in vitro study.

Notes

Acknowledgements

Sincere appreciation goes to my PhD supervisors—Prof. J. A. Alokan and Dr. A. N. Fajemisin for their mentorship role.

Availability of data materials

The data that support the findings of this study are available from Omotoso, O. B., but restriction applies to the availability of the data, which were used under license for the current study, and so are not publicly available. Data are however available from the author upon reasonable request and with permission of Omotoso, O. B.

Author’s contributions

This manuscript is a subset of my doctoral research work. I was responsible to manage all the activities of the experiment and worked in the execution of the trial and involved in the data collection and interpretation to make this manuscript. The author read and approved the

final manuscript.

Funding

Not applicable

Ethics approval and consent to participate

Not applicable

Consent for publication

Not applicable

Competing interests

The authors declare that they have no competing interests.

References

  1. Ajibade FO, Adewumi JR, Oguntuase AM (2014) Design of improved storm water management system for the Federal University of Technology, Akure. Niger J Technol 33(4):470–481CrossRefGoogle Scholar
  2. AOAC (2002) Association of Official Analytical Chemists. Official methods of analysis, 17th edn. Published by Association of Official Analytical Chemists, Washington, D.CGoogle Scholar
  3. Aregheore EM (2002) Chemical evaluation and digestibility of cocoa (Theobroma cacao) by products fed to goats. Trop Anim Health Prod 34:339–348CrossRefGoogle Scholar
  4. Babayemi OJ, Bamikole MA (2006) Effect of Tephrosia candida DC leaf and its mixtures with Guinea grass on in vitro fermentation changes as feed for ruminants in Nigeria. Pak J Nutr 5(1):14–18Google Scholar
  5. Duncan DB (1955) Multi rang and multiple F test. Biometrics 11:1–2MathSciNetCrossRefGoogle Scholar
  6. Fievez V, Babayemi OJ, Demeyer D (2005) Estimation of direct and indirect gas production in syringes: a tool to estimate short chain fatty acid that requires minimal laboratory facilities. Anim Feed Sci Technol123-124(1):197–210Google Scholar
  7. Makkar HPS (1993) Anti-nutritional factors in food for livestock. Br Soc Anim Prod 16:69–85Google Scholar
  8. Menke KH, Steingass H (1988) Estimation of the energetic fed value from chemical analysis and in vitro gas production using rumen fluid. Anim Res Devt 28:7–55Google Scholar
  9. NRC (2007). Nutrient requirements of small ruminants: sheep, goats, cervids, and new world camelids. National Academy Press, 384 p.Google Scholar
  10. Okoruwa MI, Agbonlahor I (2016) Replacement value of cocoa pod husk with soursop pulp meals for Napier grass in the practical diet of West African Dwarf sheep. Eur J Agric For Res 4(5):1–11Google Scholar
  11. Ozung PO, Kennedy OO, Agiang EA (2016) Chemical composition of differently treated forms of cocoa pod husk meal. Asian J Agric Sci 8:5–9Google Scholar
  12. SAS (2008) Statistical Analysis System Institute Inc. SAS/STAT Programme, Carry, NCGoogle Scholar
  13. Steinfeld, H., T. Wassenaar, T. and Jutzi, S. (2006). Livestock production systems in developing countries: status, drivers, trends. Rev Sci Tech 25 (2): 505-516.Google Scholar
  14. Sucharita S, Makkar HPS, Becker K (1998) Alfalfa saponins and their implications in animal nutrition. J Agric Food Chem 46:131–140CrossRefGoogle Scholar

Copyright information

© The Author(s) 2019

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  1. 1.Department of Animal Production and Health, School of Agriculture and Agricultural TechnologyFederal University of TechnologyAkureNigeria

Personalised recommendations