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Citation of this paper

Assessment of the nutritive value of fungi treated maize cob using in vitro gas production technique

A Akinfemi, O A Adu* and F Doherty**

Nasarawa State University, Keffi,Faculty of Agriculture, Department of Animal Science, PMB 135, Shabu-Lafia, Nigeria
akinjournal2000@yahoo.com
Department of Animal Production and Health, Federal University of Technology, Akure, Nigeria
** Department of Biological Science, Yaba College of Technology, Lagos, Nigeria

Abstract

The objective of the current study was to assess the changes in nutritive value of fungal treated maize cobs using in vitro gas production technique. Treatment of crop residues with some species of white-rot fungi can enhance the nutritive value. After the fungal treatment of maize (Zea mays L) cob with two white-rot fungi in a solid state fermentation, the chemical composition and in vitro digestibility of the resultant substrate was determined.

 

The results show a significant (p<0.05) increase in crude protein (CP) contents from 6.82% for the control (UM) to 10.05% for Pleurotus pulmonarius (PPM) and 10.37% for Pleurotus sajor caju (PSM). The ash and ether extracts (EE) contents also increased significantly (p<0.05). The crude fibre (CF) decreased significantly from 32.68% for UM to 22.89 for PPM and 24.14% for PSM. There were also consistent significant decreases (p<0.05) in the values obtained for cell wall contents (NDF, ADF ADL). Over utilization of the hemicellulose and cellulose by the fungi as energy source decreased the NDF. The estimated organic matter digestibility (OMD) ranged from 38.06 to 42.09%, metabolisable (ME) ranged from5.49 to 6.04 MJ/Kg DM and short chain fatty acid (SCFA) ranged from 0.4339 to 0.4974 µM. There were no significant (p>0.05)  difference in the values obtained for the degradation of the insoluble fractions (b) ML.

 

Gas production rate constant (c) was faster in the fungal treated maize cob compared with the untreated. This result suggests that fungal treatment of maize cob resulted in improved CP and digestibility, hence its potential in ruminant nutrition.

Key words: chemical composition, crop residues, in vitro digestibility, solid state fermentation, white-rot fungi


Introduction

The major constraint to livestock production in Nigeria is the scarcity of quality and sufficient supply of feed throughout the year. This is more so because of the competition between man and livestock for the available food grains. Addition to this is the increasing population at a very high rate, especially in developing countries like Nigeria. With the increasing demand for livestock products in the world economy and shrinking land area, future hope of feeding the nations and safeguarding their food security will depend on their better utilization of their non-conventional feed resources, which cannot be used as food for human (Makkar 2000).

 

The use of crop residues in animal feeding is a very common practice in tropical countries. However, these feed resources have generally been directed to ruminant production, due to the high level of the cell wall fraction (Preston and Leng 1987). An important class of non-conventional feedstuff in Nigeria is maize cob which is obtained during the processing of harvested maize. The amount of maize cob generated annually in the country increases as more people venture into the cultivation of maize cobs. In the developing countries, ruminants are feed low quality roughages in various proportions depending on the type of animal and season. But these non-conventional feedstuffs have low feeding value because of its poor protein content, energy, minerals and vitamins.

 

The quality of crop residue may be improved by physical or chemical methods, but their practical uses are limited by cost and most especially are safety concern that may result from improper handling. Information abounds on physical and chemical treatment but there is paucity of information on biological treatment of feed. Mushrooms have been reported to be capable of transforming nutritionally worthless waste into protein rich food and have been confirmed to be source of single cell protein (Kurtzman 1981; Alofe et al 1998). The cultivation of Pleurotus sajor-caju and Pleurotus pulmonarius on maize cobs may thus be a biotechnological process of converting maize cobs, which are considered to be waste into value added ruminant feed.

 

This study is therefore conducted to assess the changes in nutritive value of fungal treated maize cobs using in vitro gas production technique.

 

Materials and methods 

Samples

 

Dried samples of maize residues (maize cob) and were collected from the Teaching and Research Farm, University of Ibadan, Ibadan, Nigeria. The materials were milled and oven-treated at 65oC until a constant weight was obtained for any dry matter

 

The fungus

 

The sporophores of Pleurotus pulmonarius and Pleurotus sajor caju growing in the wild were collected from Ibadan University botanical garden. These were tissue cultured to obtain fungal mycelia (Jonathan and Fasidi 2001).The pure culture obtained was maintained on plate of potato dextrose agar (PDA).

 

Degradation of maize cob by Pleurotus pulmonarius and Pleurotus sajor caju

 

Preparation of substrate

 

The jam bottles used for this study were thoroughly washed, dried for 10 min. at 100oC. 25.00g of the dried milled substrate were weighed into each jam bottle and 70ml distilled water were added. The bottle was immediately covered with aluminium foil and sterilized in the autoclave at 121oC for 15 min. Each treatment was triplicates.

 

Inoculation

 

Each bottle was inoculated at the centre of the substrate with 2, 10.00mm mycelia disc and covered immediately. They were kept in the dark cupboard in the laboratory at 30oC and 100% RH (Relative humidity). After 21 days of inoculation, the experimental bottles were harvested by autoclaving again to terminate the mycelia growth. Samples of the biodegraded samples were oven dried to constant weight for chemical analysis and in vitro digestibility.

 

In vitro gas production

 

Rumen fluid was obtained from three West African Dwarf female goat through suction tube before the morning feed. The animals were fed with 40% concentrate feed (40% corn, 10% wheat offal, 10% palm kernel cake, 20% groundnut cake, 5% soybean meal, 10% brewers grain, 1% common salt, 3.75% oyster shell and 0.25% fishmeal) and 60% Guinea grass. Incubation was carried out according to (Menke and Steingass 1998) in 120ml calibrated syringes in three batches at 39oC. To 200mg sample in the syringe was added 30ml inoculum contained cheese cloth strained rumen liquor and buffer (9.8g  NaHCO3 + 2.77g Na2HPO4 + 0.57g KCL + 0.47g NaCL + 0.12g MgSO4. 7H20 + 0.16g CaCI2 . 2H20 in a ratio (1:4 v/v) under continuous flushing with CO2.  The gas production was measured at 3, 6, 9, 12, 15, 18, 21 and 24h. After 24 hours of incubation, 4ml of NaOH (10m) was introduced to estimate the amount of methane produced. The average volume of gas produced from the blanks was deducted from the volume of gas produced per sample. The volume of gas production characteristics were estimated using the equation Y = a + b (1 – ect) described by Ǿrskov and McDonald 1979, where Y = volume of gas produced at time‘t’, a = intercept (gas produced from the soluble fraction), b = gas production from the insoluble fraction, (a + b) = final gas produced, c = gas production rate constant for the insoluble fraction (b), t = incubation time. Metabolisable energy (ME, MJ/Kg DM) and organic matter digestibility (OMD %) were estimated as established (Menke and Steingass 1998) and short chain fatty acids (SCFA) was calculated as reported Getachew et al (1999).
 

ME = 2.20 + 0.136* GV + 0.057* CP + 0.0029*C;

OMD = 14.88 + 0.88GV + 0.45CP + 0.651XA;

SCFA = 0.0239*Gv – 0.0601
 

Where Gv, CP, CF and XA are net gas production (ml/200mg, DM) crude protein, crude fibre and ash of the incubated sample respectively.

 

Chemical composition

 

Dry matter of the samples was determined at 105oC for 8 hours. Nitrogen (N) content of the milled dried samples was determined by the standard Kjeldhal method (AOAC 1995) and the crude protein (CP) was calculated (N x 6.25).Ash content was determined using muffle furnace. Neutral detergent fibre (NDF), Acid detergent fibre (ADF) and Acid detergent lignin (ADL) was determined using the method described by Van Soest et al 1991.Hemicellulose was estimated as the difference between NDF and ADF, and cellulose estimated as the difference between ADF and ADL

 

Statistical analysis

 

Data obtained were subjected to analysis of variance (ANOVA) and mean separation when there were significant differences was by Duncan multiple range test using Statistical Analysis System (SAS) 1998 package.

 

Result and discussion 

Changes in chemical composition

 

The result of chemical composition of the treated and untreated maize cob is given in Table 1. 


Table 1.  Chemical composition (g/100g DM) of Pleurotus sajor caju and Pleurotus pulmonarius degraded maize cob

Parameters

UM

PSM

PPM

SEM

Dry Matter

88.57b

86.40c

88.72a

0.01

Crude protein

6.82c

10.37a

10.05b

0.00

Ether extract

0.38c

1.49b

1.66a

0.00

Ash

2.87c

3.20b

3.32a

0.01

Crude fiber

32.68a

24.14b

22.89c

0.00

Nitrogen Free Extract

42.75b

39.20c

37.92a

0.27

Neutral Detergent fiber

68.35a

62.52c

63.73b

0.00

Acid Detergent lignin

13.79a

11.48c

12.46b

0.00

Acid Detergent fibre

47.04a

44.56c

44.70b

0.01

Cellulose

32.25a

38.08b

32.24c

0.02

Hemicellulose

21.31a

17.96c

19.03b

0.02

a,b,c, means on the same column with different superscripts are significantly varied (P < 0.05)  UM = Control , PSM = Pleurotus sajor caju degraded maize cob, PPM = Pleurotus pulmonarius degraded maize cob, SEM= standard error of the mean


There were variations in the chemical composition of the treated and untreated maize cobs, with CP ranging from 6.82% to 10.37%, CF from 241.14% to 32.68%, NDF from 62.52 to 68.37%; ADL from 11.48 to 13.79%, ADF from 44.56 to 47.04%, cellulose from 32.24 to 33.08% and hemicellulose from 17.96 to 21.31%. The increase observed in the CP content of the fungal treated maize may probably be due to addition of fungal protein during solubilization and degradation (Belewu and Belewu 2005). CP increase could also be as a result of hydrolysis of starch to glucose and its subsequent use by same organism as a carbon source to synthesise fungal biomass rich in protein (Bender 1970; Hammond and Wood 1985). This agrees with the findings of Zadrazil 1993; Belewu and Okhawere 1998 who reported that the colonization of lignocellulosic waste by the fungi results in increase in their nutritional value. The decrease in the value of detergent fibre (hemicellulose, cellulose and lignin) and acid detergent fibre (lignin and cellulose) for the fungal treated maize cobs could be indicative of the degradation of the cell wall component of the substrates produced by extra cellular enzymes of P.ostreatus. Previous authors concluded that lignifications of structural polysaccharides not only inhibited ruminal microbial digestion of polysaccharide by forming 3-D matrix, but also that the presence of highly lignified tissues formed a physical barrier preventing accessibility of the otherwise highly digestible tissue to the action of hydrolytic enzymes of the rumen micro-organism ( Karunanandaa et al 1995), and have shown that increased digestibility was associated with the degradation of structural carbohydrates (Mukherjee and Nandi  2004).

 

Estimated organic matter digestibility (OMD), short chain fatty acid (SCFA), metabolisable energy (ME) and methane (CH4) production

 

The estimated OMD, ME and methane is shown in Table 2.


Table 2.  Organic matter digestibility (OMD)(%), short chain fatty acid (mol) and metabolisable energy (me) (MJ/Kg DM) of fungal treated and untreated maize cob

Parameters

UM

PSM

PPM

SEM

b mL

10.34

11.17

11.00

0.19

c  h-1

0.019c

0.023b

0.027a

0.00

OMD

38.06c

41.57b

42.09a

0.02

SCFA

0.434c

0.482b

0.497a

0.00

ME

5.495c

5.944b

6.041a

0.00

a,b,c, means on the same column with different superscripts are significantly varied (P < 0.05)  UM = Control , PSM = Pleurotus sajor caju degraded maize cob, PPM = Pleurotus pulmonarius degraded maize cob, b= fermentation of the insoluble but degradable fraction, c= gas production rate constant, ME = metabolisable energy,  SEM= standard error of the mean, SCFA= short chain fatty acid, OMD= organic matter digestibility


The estimated OMD was significantly higher in the fungal treated cobs compared with the untreated. The value of OMD in the present study were higher than those of rice straw, linseed straw, date stone sugar bagasse (Sallam et al 2007), wild cocoyam (Babayemi and Bamikole 2009), spent tea leaf (Babayemi 2006) mixtures of Tephosia candida and guinea grass (Babayemi and Bamikole 2006) the higher estimated OMD obtained in the fungal treated cobs implies that the microbes in the rumen and animal have increased nutrient uptake (Chumpawadee et al 2007).

 

The predicted ME also differed significantly (p<0.05) with higher value obtained in the treated substrates. These value are comparable to soyabeans hull, broken rice, mung bean, meal and rice bran (Chumpawadee et al 2007) and lower than that estimated for different parts Enterelobium cyclocarpum (Babayemi 2006). Menke and Steingass (1988) reported a strong connection between ME values measured in vivo and predicted from 24h in vitro gas production and chemical composition of feed. The in vitro gas production method has also being widely used to evaluate the energy value of several classes of feed (Getachew et al 1998; Getachew et al 2002; Aiple et al 1996). Krishnamoorthy et al (1995) also suggested in vitro gas production technique should be considered for estimating ME in tropical feedstuffs; because of evaluating ME by other technique require labour, cost and time .

 

The SCFA predicted from gas production were 0.4339µM, 0.4817µM and 0.4975 µM for the control (UM), PSM and PPM respectively. There were significant differences among the substrate with higher values obtained in the treated substrates. The higher estimated SCFA in the treated substrate might be due to increase in the CP and decrease in CF. The gas production from different classes of feed (Blummel et al 1990) incubated in vitro in buffered rumen fluid was closely related to the production of SCFA which was based on carbohydrate fermentation (Sallam et al 2007). Getachew et al (2002) reported the close association between SCFA and gas production to estimate the SCFA production from gas value, which is an indicator of energy availability to animal.

 

In vitro gas production characteristics

 

Fermentation of the insoluble but degradable fraction (b) though numerically higher in the treated substrate but was not significantly different (p>0.05). Although this is contrary to expectation, but from in vitro gas production pattern (Figure 1) more gas production was still possible beyond 24h, and when this happens, a positive increase in (b) mL is envisaged.



Figure 1.  Methane (ml/200mg DM) of maize cob


The high rate of fungal treated maize cobs could be related to its high CP content and low content of NDF, ADF and ADL (Osuga et al 2006). Kamalak et al (2005) and Abdulrazak et al (2000) reported that gas production and estimated parameters are negatively correlated with NDF and ADF.

 

Fungal treatment had significant (p<0.05) effect on the methane production. The value obtained was highest in the control (UM) followed by PSM and PPM. Methane production has negative effect on the animals in one hand as it is an energy loss to the animal and on the other hand, when accumulates in the rumen, it results in bloat (Babayemi 2006).

 

Gas volume

 

Gas volume over a period of 24h is presented in Table 3.


Table 3.  In vitro gas production of maize cob treated with two strains of fungi for a period of 24 hours

Incubation period, hours

3

6

9

12

15

18

21

24

UM

10.33

12.50

13.17b

14.00b

14.67b

16.00b

19.69

20.67b

PSM

10.05

14.00

15.00ab

16.88a

18.00a

18.33a

20.69

22.67a

PPM

12.33

15.00

17.00a

18.33a

19.33a

20.00b

21.69

23.33a

SEM

0.84

0.52

0.42

0.30

0.29

0.29

0.51

0.43

a,b, means on the same column with different superscripts are significantly varied (P < 0.05)  UM = Control , PSM = Pleurotus sajor caju degraded maize cob, PPM = Pleurotus pulmonarius degraded maize cob, ME = metabolisable energy,  SEM= standard error of the mean


The final gas produced ranked from the highest to the lowest were PPM, PSM and UM, and differed significantly (p<0.05). Menke et al (1979) suggested that gas volume at 24h after incubation is indirect with metabolisable energy in feedstuffs. Sommart et al (2000) suggested that gas volume is a good parameter from which to predict digestibility, fermentation end- product and microbial protein synthesis of the substrate by rumen microbes in the in vitro system. Furthermore, in vitro dry matter and organic matter digestibility were shown to have high correlation with gas volume (Sommart et al 2000; Nitipot and Sommart 2003). Gas volume has also shown to have a close relationship with feed intake (Blummel and Becker 1997) and growth rate (Blummel and Orskov 1993).

 

Conclusion  

 

References 

AOAC 1995 Official Methods of Analysis, 16th edition. Association of Official Analytical Chemist, Washington, DC.

 

Abdulrazak S A, Fujihara T, Ondiek J K and Orskov E R 2000 Nutritive value evaluation of some accasia tree leaves from Kenya. Animal Feed Science and Technology 85:89-98

 

Alofe F A, Odeyemi O and Oke N 1996 Three edible wild mushrooms from Nigeria: Their proximate and mineral composition. Plant foods for Human Nutrition 49(1):63-73

 

Aiple K P, Steingass H and Drochner W 1996 Prediction of net energy content of raw materials and compound feeds for ruminants by different laboratory methods. Archives of Animal Nutrition. 49:213-220

 

Babayemi O J 2006 Antinutritional factors, nutritive value and in vitro gas production of foliage and fruit of Enterolobium cyclocarpum. World Journal of Zoology 1(2):113-117

 

Babayemi O J and Bamikole M A 2006 Effect of Tephrosia candida DC leaf and its mixtures with Guinea grass on in vitro fermentation changes as feed for ruminants in Nigeria. Pakistan Journal of Nutrition 5(1): 14-18 http://www.pjbs.org/pjnonline/fin384.pdf

 

Babayemi O J and Bamikole M A 2009 Nutritive value and in vitro gas production of African wild cocoyam (Colocasia Esculentum). African Journal of Food, Agriculture, Nutrition and Development 9 (1):593-607

 

Belewu M A and Okhawere O C 1998 Evaluation of Feeding Fungi Treated Rice Husk to Ram. In Proceeding of the 25th Annual Conference and Silver Jubilee of the Nigerian Society Animal Production. Held between 21-24th March 1998 pp 321-322.

 

Chumpawadee S, Chantiratikul A and Chantiratikul P 2007 Chemical composition and Nutritional evaluation of energy feeds for ruminant using in vitro gas production technique. Pakistan Journal Nutrition 6(6):607-612 http://www.pjbs.org/pjnonline/fin749.pdf

 

Belewu M A and Belewu K Y 2005 Cultivation of Mushroom (Volvariella volvacea)  on Banana leaves. African Journal of Biotechnology  4(1): 1402-1401

 

Bender P F 1970 Underutilized resources as animal feedstuffs. National Academy Press, Washington, D.C.pp100

 

Blummel M, Ǿrskov E R, Becker K and Soller H 1990 Anwendung des Hohenheimer Gastests zur Schatzung Kinetischer Parameter der Pansenfermentation. Journal of Animal Physiology and Animal Nutrition 64:56-57

 

Blummel M and Becker K 1997 The degradability characteristics of fifty-four roughages and roughage neural detergent fibre as described in vitro gas production and their relationship to voluntary feed intake. British Journal of Nutrition 77:757-768 http://journals.cambridge.org/download.php?file=%2FBJN%2FBJN77_05%2FS0007114597000743a.pdf&code=7f16b7010f382f7d2cf84720c13bb8d5

 

Blummel M and Ǿrskov E R 1993Comparison of in vitro gas production and nylon bag technique degradability of roughages in predicting feed intake in cattle. Animal Feed Science and Technology 40:109-119

 

Fievez V, Babayemi O J and Demeyer D 2005 Estimation of direct and indirect gas production in syringes: A tool to estimate short chain fatty acid production requiring minimal laboratory facilities. Animal Feed Science and Technology 123-124:197-210

 

Getachew G M, Blummel H P S Makkar and Becker K 1999 In vitro gas measuring techniques for assessment of nutritional quality of feeds: A review. Animal Feed Science and Technology 72: 261-281

 

Getachew G, Crovetto G M, Fondivila M, Krishnamoorthy U, Singh B, Spaghero M, Steingass H, Robinson P H and Kailas M M 2002 Laboratory variation of 24 h in vitro gas production and estimated metabolisable energy values of ruminant feeds. Animal Feed Science and Technolology 102: 169-180

 

Hammond  J B W and Wood D A 1985 Metabolism, biochemistry and physiology. In the biology and technology of the cultivated mushrooms. Edited by Flagy PB, Spencer DM and  Wood DA. John wiley and Sons, Chichester. pp 63-80

 

Jonathan S G and Fasidi I O 2001 Effect of carbon, nitrogen and mineral sources on growth Psathyyerella atroumbonata (Pegler), A Nigerian edible mushroom. Food Chemistry 72:479-483

 

Kamalak A 2005 Determination of the nutritive value of leaves of a native grown shrub, Glycyrriza glabra usind in vitro and in situ measurements. Small Ruminant Resources. In Press

 

Karunanandaa V K, Varga G A, Akin D E, Rigsby L L and Royse D J 1995 Botanical fractions of rice straw colonized by white rot fungi: changes in chemical composition and structure. Animal feed Science and Technology  55 (3-4): 179-199

 

Krishnamoorthy U, Soller H, Steingass H and  Menke K H 1995 Energy and protein evaluation of tropical feedstuff for whole tract and ruminal digestion by chemical analysis and rumen inoculum studies in vitro. Animal Feed Science and Technology 52:178-190

 

Kurtzman R H Jr 1981 Metabolism and culture of Pleurotus, the oyster mushroom. Taiwan Mushroom 3:1-13

 

Makkar H P S 2000 Application of the in vitro gas method in the evaluation of feed resources, and enhancement of nutritional value of tannin-rich tree leaves and agro-industrial by product. In: Development and field evaluation of animal feed supplemental packages. Proceeding of final review meeting of IAEA Technical cooperation Regional AFRA Project organised by Join FAO/IAEA Division of Nuclear Technique in Food and Agriculture held in Cairo Egypt,25-29 Nov 2000.pp23-40 http://www-naweb.iaea.org/nafa/aph/public/iaea-tecdoc-1294.pdf

 

Menke K H and Steingass H 1988 Estimation of the energetic feed value from chemical analysis and in vitro gas production using rumen fluid. Animal Resources and Development. 28:7 – 55

 

Menke K H, Raab L, Salewski A, Steingass H and Schneider W 1979 The Estimation of the Digestibility and Metabolizable Energy Content of Ruminant Feeding Stuffs from the Gas Production when they are incubated with Rumen Liquor. Journal of Agricultural Science, 93: 217-222.

 

Mukherjee R and Nandi B 2004 Improvement of in vitro digestibility through biological treatment of water hyacinth biomass by two Pleurotus species. International biodeterioration and biodegradation,  53 (1): 7-12

 

Nitipot P and Sommart K 2003 Evaluation of ruminant nutritive value of cassava starch industry by-products, energy feed sources and roughages using in vitro gas production technique. In: proceeding of Annual Agricultural Seminar for year 2003, 27-28 January, KKU, pp179-190

 

Orskov E R and McDonald L M 1979 The estimation of protein degradability in the rumen from incubation measurement weighted according to rate of passage. Journal of Agricultural Science, Cambridge  92: 499-503

 

Osuga I M, Abdulrazaq S A, Ichinohe T and Fujihara T 2006 Rumen degradation and in vitro gas production parameters in some browse forages, grasses and maize stover from Kenya. Journal of food. Agriculture and Environment  4 (2): 60-64

 

Preston T R and Leng R A 1987 Matching ruminant production systems with available resources in the tropics and subtropics. Technical Centter for Agricultural and Rural Cooperation. Pernambul Books, Armidale pp245

 

Sallam S M A, Nasser M E A, El-Waziry A M, Bueno I C S and Abdalla A L 2007 Use of an in vitro ruminant gas production technique to evaluate some ruminant feedstuffs. Journal of Applied Sciences Resources 3(1): 33-41

 

SAS 1998 Statistical Analysis System Institute Inc., SAS/ STAT. User’s guide. Version6.3rd edition Carry. North Carolina,USA.943

 

Sommart K, Parker P, Rowlinson P and Wanapat M 2000 Fermentation characteristics and microbial protein synthesis in vitro system using cassava, rice straw and dried ruzi grass as substrates. Asian-Australian  Journal of Animal Science 13:1084-1093

 

Van Soest P J, Robertson J B and Lewis B A 1991 Methods for dietary fiber neutral detergent fiber and non – starch polysaccharides in relation to annual nutrition. Journal of Dairy Science 74: 3583 – 3597 http://jds.fass.org/cgi/reprint/74/10/3583

 

Zadrazil F 1993 Conversion of Lignocellulose waste into animal feed with White rots Fungi. Proceedings of the international conference of mushroom Biology. Pp. 55-116



Received 8 April 2009; Accepted 10 July 2009; Published 1 November 2009

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