Phone : 0092 300 7786573

Journal of Animal Health and Production

Download PDF Download ePUB
JAHP_5_3_97-102

 

 

Research Article

 

 

Effect of Feeding Wheat and Paddy Straw on Blood Parameters and Serum Enzymes in Goats

 

Imran Ahmad Ganai1*, Ankur Rastogi1, R.K. Sharma1, Zulfiqarul Haq1, Himalaya Kumar1

1Division of Animal Nutrition, FVSc & AH, Shere Kashmir University of Agricultural Sciences & Technology of Jammu, RS Pura, 181102, India.

 

Abstract | Paddy and wheat generate multi-million tons of straw as residue. These two straws although similar in their nutrient content are quite different in microstructure and non-nutritive chemical composition. Present study scrutinized the effect of these straws when fed in combination as compared to fed as sole roughage on blood biochemical profile and serum enzymes. Eighteen non-descript local adult male goats were randomly divided into three equal groups as per randomized block design and were offered concentrate mixture @20g /kg metabolic body weight (W0.75) along with either wheat straw (WS), paddy straw (PS) or wheat-paddy straw as 60:40 mix (WP) ad libitum. Feeding trial lasted for 30 days. The haemoglobin, total serum protein, albumin, blood urea nitrogen and serum enzymes (alanine transaminase and aspartate aminotransferase) were comparable among goats irrespective of the diets. It may be concluded that wheat and paddy straw can be used as sole roughage or in combination without effecting blood biochemical profile and serum enzymes of goats.

 

Keywords | Goats, Paddy straw, Straw combination, Wheat straw

 

Editor | Asghar Ali Kamboh, Sindh Agriculture University, Tandojam, Pakistan.

Received | September 08, 2017; Accepted | September 27, 2017; Published | September 29, 2017

*Correspondence | Imran Ahmad Ganai, Division of Animal Nutrition, FVSc & AH, Shere Kashmir University of Agricultural Sciences & Technology of Jammu, RS Pura, 181102, India; Email: imranganai85@gmail.com

Citation | Ganai IA, Rastogi A, Sharma RK, Haq Z, Kumar H (2017). Effect of feeding wheat and paddy straw on blood parameters and serum enzymes in goats. J. Anim. Health Prod. 5(3): 97-102.

DOI | http://dx.doi.org/10.17582/journal.jahp/2017/5.3.97.102

ISSN (Online) | 2308-2801; ISSN (Print) | 2309-3331

Copyright © 2017 Ganai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

 

INTRODUCTION

 

A major portion of ration of ruminant livestock in South-east Asia including India is based on cereal crop residues. The scarcity of green fodder, pasture and quality hay has increased the onus over cereal crop residues, as their feeding to livestock offers no direct competition with human resources and requirements. Alternative mode of disposal of cereal straw by burning is a major source of land and air pollution (Andreae, 2001; Zeng et al., 2007). However, using it as a feedstuff for ruminant animals makes it an extremely important renewable resource (Severe and ZoBell, 2012).

 

Rice (Oryza sativa L.) - wheat (Triticum aestivum L.) (RW) cropping system has been developed through the introduction of rice in the traditional wheat-growing areas and vice versa in India (Paroda et al., 1994). Increased production of rice and wheat from last decade results enhanced residue production. There is a large variability in production of crop residues, and their use depends on the crops grown, cropping intensity, and productivity in different regions of India. There is mean residue production of about 6.7 and 5.0 metric tonne/h for paddy and wheat, respectively (Lal, 2005). Cereal crops (rice, wheat, maize, millets) contribute 70% of the total crop residues (352 Mt) including 34% by rice and 22% by wheat crops, out of which, the RW system accounts for approximately one-fourth of the total crop residues produced in India (Sarkar et al., 1999).

 

Paddy and wheat are both important cereal crops of Jammu and Kashmir (J&K) state. About 290.99 thousand hectares of land in J&K is under wheat cultivation, producing about 5819.5 thousand quintals of grain yield (GoJK, 2015), concurrently producing roughly 1.5 times the weight as wheat straw and twice the weight as rice straw (Lal, 2005).

 

Paddy straws either burned, left on the field before the next ploughing, ploughed down as a soil improver or used as a feed for livestock (Kadam et al., 2000). It has poor nutritive value (Sarnklong et al., 2010) containing less lignin, but more silica and oxalic acid as compared to other cereal straws (Van Soest, 1981; Juliano, 1985). The slow and partial ruminal degradation of fibrous carbohydrates and the little content of nitrogen are the main limiting factors of rice straw, affecting its value as feed (Van Soest, 2006).Wheat straw is generally low in crude protein and phosphorous, limited in calcium, and high in fiber and lignin (Anderson, 1978). As such, it typically causes a decrease in voluntary intake, slowing of passage rate, and a decrease in digestibility.

 

In our previous study, we determined the chemical composition and in vitro dry matter degradability (IVDMD) of wheat and paddy straw in combination and concluded that straw combination of W60P40 was suitable for small ruminant feeding (Ganai et al., 2017).With this background, present study was envisaged to scrutinize the effect of this combination of straws on blood parameters and serum enzymes in goats when fed in combination as compared to their sole feeding.

 

MATERIAL AND METHODS

 

Present study was conducted in the Division of Animal Nutrition, F.V.Sc. & A.H., SKUAST-J, R.S. Pura, Jammu. Eighteen non-descript local adult male goats were taken as the experimental animals. Goats were randomly divided into three equal groups of six animals each as per randomised block design and were subjected to three dietary treatments namely WS, PS and WP.The groups were subjected to dietary treatments viz., WS (Wheat straw ad libitum + concentrate mixture @20g /kg metabolic body weight (W0.75); PS (Paddy straw ad libitum + concentrate mixture @ 20g/kg W0.75) and WP (wheat (60%) and paddy straw (40%) combination ad libitum + concentrate mixture @20g/kg W0.75). The composition of concentrate mixture (mustard de oiled cake-40%; wheat bran-32%; barley-25%, mineral mixture-2%, salt-1%) was formulated to meet the nutrient requirements of the animals as per ICAR (2013).

 

All the goats were reared under uniform management conditions with the provision of individual housing in well-ventilated cement floored sheds up to end of trial (30 d). The goats were treated for ecto- and endo-parasites with Butox(R) spray (Intervet) and Panacur(R) bolus (Intervet), respectively before the start of study. Clean, wholesome drinking water was provided twice daily on ad libitum basis. Each group of the goats were fed with respective straw twice daily viz. in morning at 8:30 am and in evening at 4:00 pm along with daily allowance of concentrate mixture divided into two equal parts.

 

To collaborate the effect of straw feeding on blood parameters, periodic monitoring of blood parameters was carried out. Blood from experimental goats was collected early in the morning before feeding and watering, by jugular vein puncture at day 0, 15 and 30 of experimental trial. About 10 ml of whole blood was collected from every animal, from that 2 ml was mixed with EDTA for haematological parameters and the remaining was taken in well cleaned, dry, sterilized and labelled test tubes and allowed to clot. After clotting, the tubes were centrifuged to collect serum. The serum samples were collected in labelled containers separately and then stored in deep freeze (-20°C) for further analysis. Haemoglobin was quantified in whole blood samples by Drabkin method (Crook JD, 1985). The estimation of total serum protein, albumin, blood urea nitrogen (BUN), alanine transaminase (ALT) and aspartate aminotransferase (AST) were carried out using “ERBA Diagnostic Kits” manufactured by Transasia Bio-Medicals Limited in technical collaboration with ERBA diagnostics Mannheim GmbH.

 

STATISTICAL ANALYSIS

 

The data generated was then subjected to multivariate analysis (Snedecor and Cochran, 1994). The means bearing significant difference (at P < 0.05) were ranked by Duncan’s multiple range test as per Duncan (1955).

 

RESULTS

 

The blood biochemical profile and levels of serum enzymes of experimental goats are presented in Table 1 and Table 2 respectively.

 

Haemoglobin

The mean haemoglobin level in WS group, PS group and WP group was 10.36±0.263 g/dl, 10.83±0.198 g/dl, and 10.92±0.159 g/dl, respectively. There was no significant (P>0.05) difference in haemoglobin level between the periods as well as between the groups (Table 1).

 

Total Serum Protein

The mean level of total serum protein was 5.75±0.137 g/dl for the experimental goats, with 5.97±0.070 g/dl in the WS group, 5.78±0.280 g/dl in the PS group and 5.55±0.274 g/dl in the WP group. There was no significant (P>0.05) difference between the groups as well as among periods (Table 1).


Serum Albumin and Globulin

The mean serum albumin content of the goats was comparable (P>0.05) among the three groups with an overall mean albumin concentration of 3.18± 0.055 g/dl. There was no significant (P>0.05) difference among periods. The mean globulin content WS, PS group and that of WP group was 2.65±0.090 g/dl, 2.58±0.271 g/dl and 2.48±0.304 g/dl, respectively. There was no significant (P>0.05) difference periodically as well as between the groups in globulin levels (Table 1).

 

Table 1: Effect of combined feeding of wheat and paddy strawon levels of blood bio-chemicals of experimental goat

 

Attributes/Treatments Days from onset of trial Treatment Mean ± SEM Pvalue
 

0th Day

15th Day

30th Day

   

Haemoglobin (g dl-1)

         
WS 10.3 10.48 10.29 10.36±0.263  
PS 10.82 10.77 10.91 10.83±0.198  
WP 10.97 10.84 10.96 10.92±0.159  
Period mean ± SEM 10.72±0.226 10.71±0.232 10.74±0.190 10.72±0.122 0.996
P value       0.177  

Total Protein (g dl-1)

         
WS 5.85 6.03 6.03 5.97±0.070  
PS 5.63 5.88 5.83 5.78±0.280  
WP 5.78 5.42 5.44 5.55±0.274  
Period mean ± SEM 5.75±0.222 5.75±0.252 5.74±0.257 5.75±0.137 0.998
P value       0.512  

Albumin (g dl-1)

         
WS 3.18 3.38 3.4

3.32±0.081

 
PS 3.2 3.08 3.3 3.19±0.082  
WP 2.95 3.06 3.17 3.06±0.105  
Period mean ± SEM 3.10±0.123 3.16±0.078 3.28±0.078 3.18±0.055 0.429
P value       0.192  

Globulin (g dl-1)

         
WS 2.68 2.65 2.63 2.65±0.090  
PS 2.43 2.8 2.53 2.58±0.271  
WP 2.83 2.36 2.27 2.48±0.304  
Period mean ± SEM 2.66±0.273 2.58±0.237 2.46±0.249 2.57±0.143 0.902
P value       0.907  
A:G Ratio          
WS 1.21 1.29 1.33 1.28±0.067  
PS 1.63 1.15 1.61 1.46±0.222  
WP 1.29 1.73 1.64 1.55±0.215  
Period mean ± SEM 1.37±0.199 1.42±0.201 1.53±0.174 1.44±0.108 0.847
P value       0.610  

BUN (mg dl-1)

         
WS 26.72 26.94 26.88 26.84±0.537  
PS 25.27 25.08 24.77 25.04±0.393  
WP 26.25 26.51 25.88 26.21±0.642  
Period mean ± SEM 26.09±0.585 26.20±0.534 25.84±0.653 26.05±0.334 0.923
P value       0.139  

 

WS: wheat straw; PS: paddy straw; WP: wheat-paddy straw; A:G ratio: albumin: globulin ratio; BUN: blood urea nitrogen


Albumin: Globulin (A:G) Ratio

Mean A:G ratio in WS, PS group and that of WP group was 1.28±0.067, 1.46±0.222 and 1.55±0.215, respectively. There was no significant (P>0.05) difference periodically as well as between the animals of dietary groups (Table 1).

 

Blood Urea Nitrogen

Mean BUN concentration (mg/dl) in WS, PS and WP group animals was 26.84±0.537, 25.04±0.393 and 26.21±0.642, respectively. There was no significant (P>0.05) difference in BUN level of experimental goats between the periods as well as between the groups (Table 1).

 

Table 2: Effect of combined feeding of wheat and paddy straw on levels of serum enzymesof experimental goat

 

Attributes/Treatments Days from onset of trial Treatment Mean ± SEM Pvalue
 

0th Day

15th Day

30th Day

   

AST (IU L-1)

         
WS 57.05 63.5 64.48 61.68±2.902  
PS 62.74 69.5 75.38 69.20±3.654  
WP 66.8 75.44 74.94 72.39±2.910  
Period mean ± SEM 62.55±2.902 69.94±3.183 71.85±3.505 68.11±1.916 0.111
P value       0.066  

ALT (IU L-1)

         
WS 15 15.33 15.5 15.28±0.164  
PS 16.13 15.45 16.2 15.93±0.554  
WP 15.48 15.12 15.14 15.25±0.179  
Period mean ± SEM 15.53±0.366 15.28±0.342 15.58±0.308 15.46±0.192 0.809
P value       0.334  
AST:ALT ratio          
WS 3.80 4.17 4.17 4.05±0.207  
PS 3.92 4.6 4.73 4.42±0.302  
WP 4.34 5.00 4.95 4.76±0.209  
Period mean ± SEM 4.04±0.190 4.62±0.267 4.64±0.259 4.44±0.143 0.172
P value       0.133  

 

WS: wheat straw; PS: paddy straw; WP: wheat-paddy straw; ALT: alanine transaminase; AST: aspartate aminotransferas

 

Aspartate Aminotransferase

Mean AST level (IU/L) in serum of WS, PS group and that of WP group was 61.68± 2.902, 69.20± 3.654 and 72.39± 2.910, respectively. No significant (P>0.05 difference or interaction was observed between dietary groups and periodic recordings (Table 2).

 

Alanine Transaminase

Mean ALT level (IU/L) were 15.28± 0.164, 15.93 ± 0.554 and 15.25± 0.179 in the serum of WS, PS and WP group animals. No significant (P>0.05) difference or interaction was observed among dietary groups and periodic recordings (Table 2).

 

Aspartate Aminotransferase: Alanine Transaminase Ratio (Ast: Alt Ratio)

Mean AST:ALT ratio in WS, PS group and that of WP group was 4.05±0.207, 4.42±0.302 and 4.76±0.209, respectively. There was no significant (P>0.05) difference periodically as well as between the animals of dietary groups (Table 2).

 

 

DISCUSSION

 

The haematological parameters like haemoglobin are indicators of erythrocytic normalcy and general well-being of the animals (Radositits et al., 2007). The mean haemoglobin level of the experimental animals was within the normal range (8–12 g/dl) as per Kaneko et al. (1997) for goats. This suggests that the general health of all experimental goats in the present study remained optimum. No significant (P>0.05) difference in haemoglobin level between the periods as well as between the groups indicates no effect of dietary treatment.

 

Serum concentration of proteins depends upon a number of factors like extent, duration and nature of the hepatic disorder; the inflammatory or metabolic hepatic process and the presence of other organ disorders. The levels of total protein and serum albumin indicates biosynthetic capabilities of liver (Thapa and Walia, 2007) and hepatocellular toxicity is often indicated by decline in albumin:globulin ratio (Singh et al., 2011). An increase in the principal serum protein, albumin, indicates dehydration, whereas decrease in its level indicates liver, kidney, gastrointestinal disease and malnutrition (Kaneko et al., 1997).Mean total serum protein level in experimental goats was slightly lower than the normal reference range of 6.0-7.5 g/dl for goats (Kaneko et al., 1997), however, levels observed are similar to reports of previous workers with similar experimental animals (Bashir et al., 2014, Mir et al., 2014, Ishfaq et al., 2017). Comparable (P>0.05) total protein levels obtained across periods and across different groups indicate that dietary regimens have not compromised the liver functionalities in terms of biosynthesis. Similar observations were recorded with serum albumin and globulin levels.

 

Blood urea nitrogen (BUN) levels are an indicator of protein nutrition status of the animal (Baker et al., 1995). The values of the BUN were higher than the normal range (10-20 mg/dl) as reported by Kaneko et al. (1997) for goats. Blood urea nitrogen levels are similar to that reported by Jan et al. (2015) while working with similar experimental animals. Protein digestion in ruminants results in unused ruminal ammonia being transported to the liver via the portal blood where it is converted to urea. This together with urea from deamination of amino acids arising from post-ruminal digestion and systemic protein turnover then circulates in the blood (Hammond and Chase, 1996). In healthy ruminants, BUN concentrations indicate the protein to energy ratio in the diet (Baker et al., 1995). Increased dietary protein with constant energy intake, increased solubility or degradability of dietary protein resulted with high BUN while increasing energy with constant protein intake and increased level of feed intake led to a decrease in BUN (Baker et al., 1995, Kirchgessner et al., 1986). The protein source used in concentrate mixture in present study is mustard oil cake that is known to contain high percentage of rumen degradable protein (Mahima et al., 2015) and this may be the reason for higher BUN levels in the experimental goats, irrespective of the dietary treatments.

 

The activity of AST and ALT is an indicator of damage to liver and muscles (Silanikove et al., 1996). These enzymes are most commonly used biomarkers for hepatic function assay. In contrast to ALT, which is liver specific, AST is a general marker of tissue damage. The ratio of serum AST to ALT can be used to differentiate liver damage from other organ damage (Nathwani et al., 2005). The comparable level of AST and ALT irrespective of dietary treatment, observed in this study reflects no adverse effect of type of straw on liver, kidney and muscle mass. This also suggests that the energy and protein intake of animals was sufficient to maintain body weight and to prevent muscle breakdown. No significant (P>0.05) difference or interaction was observed among dietary groups and periodic recordings.

 

CONCLUSION

 

Wheat and paddy straw can be used as sole roughage or in combination in goats’ ration without effecting blood biochemical profile and serum enzymes of goats.

 

ACKNOWLEDGEMENT

 

The facilities provided by the Division of Animal Nutrition , FVSc & AH, SKUAST-J are duly acknowledged.

 

CONFLICT OF INTEREST

 

The authors have no conflict of interest with each other or any organization.

 

Authors Contribution

 

This manuscript is the part of MVSc thesis work of the corresponding author under supervision of Dr Ankur Rastogi in Division of Animal Nutrition, SKUAST-J headed by Dr R.K.Sharma.

 

REFERENCES

 

  • Anderson DC (1978). Use of cereal residues in beef cattle production systems. J. Anim. Sci. 46: 849-861. https://doi.org/10.2527/jas1978.463849x
  • Andreae MO (2001). Emission of trace gases and aerosols from biomass burning. Global Biogeochem. Cycles. 15(4): 955-966. https://doi.org/10.1029/2000GB001382
  • Baker LD, Ferguson JD, Chalupa W (1995). Responses in urea and true protein of milk to different protein feeding schemes for dairy cows. J. Dairy Sci. 78: 2424-2434. https://doi.org/10.3168/jds.S0022-0302(95)76871-0
  • Bashir Y, Sharma RK, Rastogi A, Pathak AK, Khan N (2014). Effect of dietary incorporation of olive (Olea europoea) meal on live weight and heamato-biochemical profile of goats. Vet. Practitioner. 15(1): 157-159.
  • Duncan DB (1955). Multiple Ranges and Multiple F-Tests. Biometrics. 11: 1-42. https://doi.org/10.2307/3001478
  • Cook JD (1985). Measurement of iron status. A report of the International Nutritional Anaemia Consultive Group (INACG). New York: Washington DC; Ch.II: Pp 4.
  • Go JK (2015). Economic Survey 2014-15 (Volume 1), Directorate of Economics and Statistics, Government of Jammu and Kashmir, Jammu and Kashmir, India.
  • Ganai IA, Rastogi A, Sharma RK, Wali A, Saharan V (2017). Chemical composition and in vitro dry matter degradability of combination of wheat and paddy straw for small ruminant feeding. J. Entomol. Zool. Studies. 5(4): 1755-1760
  • Hammond AC, Chase Jr CC (1996). Cattle nutritional and reproductive status through blood and milk indicators. In: Proceedings Tropileche Workshop, CIAT, Cali, Colombia.
  • ICAR (2013). Nutrient requirements of Animals - Sheep, Goat and Rabbit. ICAR-NIANP, Indian Council of Agriculture Research, India.
  • Ishfaq A, Sharma RK, Rastogi A, Malla BA, Rather SA (2017). Effect of lime treated olive cake on nutrient utilization and performance of male goats. Indian J. Anim. Res. 51(2): 286-290.
  • Jan OQ, Kamili N, Ashraf A, Iqbal A, Sharma RK, Rastogi A (2015). Haematobiochemical parameters of goats fed tannin rich Psidiumguajava and Carissa spinarum against Haemonchuscontortus infection in India. J. Parasit. Dis. 39(1): 41-48. https://doi.org/10.1007/s12639-013-0278-5
  • Juliano BO (1985)Rice hull and rice straw. In: B.O. Juliano (ed.), Rice Chemistry and Technology. 2nd ed. American Association of Cereal Chemists, St Paul, MN, USA.
  • Kadam KL, Forrest LH, Jacobson WA (2000). Rice straw as a lignocellulosic resource: collection, processing, transportation, and environmental aspects. Biomass and Bioenergy.18: 369-389. https://doi.org/10.1016/S0961-9534(00)00005-2
  • Kaneko JJ, Harvey JW, Bruss ML (1997). Clinical biochemistry of domestic animals, VI ed. Academic press. San Diego, California, USA.
  • Kirchgessner M, Kreuzer M, Dora AR (1986). Milk urea and protein content to diagnose energy and protein malnutrition of dairy cows. Archives Anim. Nutr. Berlin. 36: 192-197. https://doi.org/10.1080/17450398609425260
  • Lal R (2005). World crop residues production and implications of its use as a biofuel. Environ. Int. 31: 575-584. https://doi.org/10.1016/j.envint.2004.09.005
  • Mahima Kumar V, Tomar SK, Roy D, Kumar M (2015). Effect of varying levels of formaldehyde treatment of mustard oil cake on rumen fermentation, digestibility in wheat straw based total mixed diets in vitro. Vet. World. 8(4): 551-555. https://doi.org/10.14202/vetworld.2015.551-555
  • Mir MA (2014). Effect of Dietary Incorporation of Walnut cake (Juglansregia) on the Performance of Goats. MVSc Thesis, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, R S Pura, Jammu.
  • Nathwani RA, Pais S, Reynolds TB, Kaplowitz N (2005). Serum alanine aminotransferase in skeletal muscle diseases. Hepatology. 41: 380-382.
  • Paroda RS, Woodhead T, Singh RB (1994). Sustainability of rice-wheat production systems in Asia, RAPA Publication 1994/11.FAO, Bangkok.
  • Radositits OM, Gay CC, Hinchcliff KW, Constable PD  (2007). Veterinary Medicine, 10thEdn. Saunders-Elsevier, London.
  • Sarkar A, Yadav RL, Gangwar B, Bhatia PC (1999). Crop Residues in India. Technical Bulletin. Directorate of Cropping System Research, Modipuram, India.
  • Sarnklong C, Cone JW, Pellikaan W, Hendriks WH (2010). Utilization of Rice Straw and Different Treatments to Improve Its Feed Value for Ruminants: A Review, Asian-Australasian J. Anim. Sci. 23(5): 680-692 https://doi.org/10.5713/ajas.2010.80619
  • Severe J, ZoBell DR (2012). Technical aspects for the utilization of small grain straws as feed energy sources for ruminants: emphasis on beef cattle. Utah State University-Extension publication, Paper 95.
  • Silanikove N, Iboa GN, Nir I, Perevolotsy A, Nitsan Z (1996). Effect of dietary supplementation of polyethylene glycol on intake and digestion of tannin containing leaves by goats. J. Agric. Food Chem. 44: 199-205. https://doi.org/10.1021/jf950189b
  • Singh SP, Singh AP, Singh MP, Singh VP, Singh MV, Kumar V, Singh SK (2011). Zinc and crop residue management under rice-wheat cropping system in calcareous soil. Proceedings of the Third International Zinc Symposium- Improving crop production and human health. October 10-14, 2011, Hyderabad, India.
  • Snedecor GW, Cochran WG (1994). Statistical methods. 8thEdition, East West Press Private Limited, New Delhi.
  • Thapa BR, Walia A (2007). Liver function tests and their interpretation. Indian J. Pediat.74: 663-671. 
https://doi.org/10.1007/s12098-007-0118-7
  • Van Soest PJ (1981). Limiting factors in plant residues of low biodegradability. Agric. Environ. 6(2-3): 135-143. https://doi.org/10.1016/0304-1131(81)90005-9
  • Van Soest PJ (2006). Review: rice straw, the role of silica and treatments to improve quality. Anim. Feed Sci. Technol. 130: 137-171. https://doi.org/10.1016/j.anifeedsci.2006.01.023
  • Zeng X, Ma Y, Ma L (2007). Utilization of straw in biomass energy in china. Renew. Sustain. Energy Rev. 11(5): 976–987. https://doi.org/10.1016/j.biombioe.2006.08.004
  •