Research Article

Influence of Fermentation Duration on Rice Bran Fermented with Local Microorganisms Derived from Kacang Goat Rumen Fluid and Palmyra Sap

Theresia Nur Indah Koni1*, Oswilda Henyati1, Stormy Vertigo1, Tri Anggarini Yuniwati Foenay2

1Feed Technology Study Program, Department of Animal Husbandry, Politeknik Pertanian Negeri Kupang, Kupang, Indonesia; 2Animal Production Study Program, Department of Animal Husbandry, Politeknik Pertanian Negeri Kupang, Kupang, Indonesia, Jl. Prof. Dr. Herman Yohanes Kel. Lasiana Kupang 85011. East Nusa Tenggara 85011.

Received | October 29, 2025; Accepted | January 26, 2026; Published | April 02, 2026

*Correspondence | Theresia Nur Indah Koni, Feed Technology Study Program, Department of Animal Husbandry, Politeknik Pertanian Negeri Kupang, Kupang, Indonesia; Email: [email protected]

Citation | Koni TNI, Henyati O, Vertigo S, Foenay TAY (2026). Influence of fermentation duration on rice bran fermented with local microorganisms derived from Kacang goat rumen fluid and palmyra sap. J. Anim. Health Prod. 14(2): 569-573.

DOI | https://dx.doi.org/10.17582/journal.jahp/2026/14.2.569.573

ISSN (Online) | 2308-2801

Copyright: 2026 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

Rice bran is a by-product of rice milling commonly used as a feed ingredient for poultry and livestock (Debi et al., 2022). It can be included up to 10% in poultry diets (Kim et al., 2017). However, its utilization is limited by high crude fiber content 24 g/100 g (Koni et al., 2022) and phytic acid concentration 7.30 mg/100 g (Koni et al., 2025), which reduce nutrient digestibility and mineral bioavailability. Fermentation is an effective biological process to decrease crude fiber and phytic acid content, thereby improving feed quality (Munira et al., 2016; Ibrahim and Usman, 2019). Microbial inoculants used in fermentation can be derived from local resources such as rumen fluid and natural plant saps. Goat rumen fluid contains cellulolytic and phytase-producing microorganisms (Islam et al., 2022). Goat rumen harbors diverse microbial phyla, including Bacteroidetes, Firmicutes, and Proteobacteria, which are dominated by genera such as Prevotella, Ruminococcus, Butyrivibrio, and Succinivibrio. These microorganisms contribute to the degradation of crude fiber, protein, and lipids in feed materials (Liu et al., 2017). Ruminococcus is composed of two strong fiber digesting bacterial species, Ruminococcus albus and Ruminococcus flavefaciens, which can produce a large amount of cellulases and hemicellulases (Odeyemi et al., 2020). Goat rumen fluid inclusion in rice bran fermentation has been shown to reduce crude fiber (Ermalia et al., 2016). Similarly, palmyra sap (Borassus flabellifer) is rich in fermentable sugars and contains Saccharomyces cerevisiae and lactic acid bacteria (Chayaningsih, 2006; Irmayuni et al., 2018), both of which enhance fermentation. palmyra sap supplementation at 10% was previously found to improve the nutritional profile of rice bran (Koni et al., 2023).

This study utilized a mixture of Kacang goat rumen fluid and palmyra sap to produce local microorganisms (LM-KGRFPS) based on the modified method of Sio et al. (2022). The duration of fermentation influences microbial activity and enzyme production (Mantut et al., 2019), which are key determinants of nutrient modification. Therefore, this study aimed to evaluate the effects of fermentation duration using LM-KGRFPS on the fermentation characteristics and nutrient composition of rice bran.

MATERIALS AND METHODS

Materials

Rice bran was obtained from a local rice mill in Kaniti, Kupang Regency, East Nusa Tenggara, Indonesia. Palmyra sap was collected from palm tappers in Lasiana, Kupang City, and Kacang goat rumen fluid was obtained from a local slaughterhouse in Pasir Panjang, Kota Lama Kupang City.

Preparation of rice bran

Rice bran was cleaned to remove impurities such as husks and stones. The cleaned material was analyzed for initial nutrient composition at the Nutrition and Animal Feed Laboratory, Politeknik Pertanian Negeri Kupang. The proximate and mineral composition of the unfermented rice bran is presented in Table 1.

Production of local microorganisms (LM-KGRFPS)

Goat rumen fluid from Kacang goats was mixed with palmyra sap and a sugar solution following a modified procedure of Foenay et al. (2025). The mixture contained 1000 mL Kacang goat rumen fluid, 100 mL palmyra sap, and 500 mL sugar solution (prepared by dissolving 250 g sugar in 500 mL water). The mixture was incubated in airtight containers at room temperature for eight days to allow fermentation.

 

Table 1: Nutrient composition of rice bran before fermentation.

Nutrient component	Unit	Value
Dry matter*	%	92.7
Crude fat*	%	1.76
Crude fibre*	%	25.8
Crude protein*	%	7.65
Ash*	%	11.2
Calcium (Ca)**	mg/kg	2715
Phosphorus (P)**	mg/kg	5069

 

*Analyzed at the Nutrition and Animal Feed Laboratory, Politeknik Pertanian Negeri Kupang (2025). ** Laboratory of Nutritional Biochemistry, Faculty of Animal Science, Universitas Gadjah Mada (2025).

 

Rice bran fermentation

Fermentation was conducted following Koni et al. (2023). The rice bran was adjusted to 65% dry matter and 35% moisture, mixed with 10% LM-KGRFPS (v/w), and placed in 2-kg plastic jars. The jars were sealed anaerobically and incubated for 0, 6, 12, and 18 days.

Measurement of fermentation characteristics and nutrient composition

The pH was measured using a pH meter following the procedures of Bernardes et al. (2019). Ammonia nitrogen (N-NH₃) and lactic acid were determined according to Matias et al. (2020) and Ergin and Gumus (2020) respectively. Nutrient composition (crude protein, crude fiber, crude fat, ash, calcium, and phosphorus) was analyzed using Association of Official Analytical Chemists (AOAC, 2005) procedures.

Statistical analysis

The experiment followed a completely randomized design with four treatments (0, 6, 12, and 18 days) and five replications. Data were analyzed using Analysis of variance and significant differences among means were determined by Duncan’s Multiple Range Test.

RESULTS AND DISCUSSION

Fermentation characteristics of rice bran

The pH, lactic acid, and N-NH₃ concentrations of rice bran fermented with LM-KGRFPS for different durations are presented in Table 2. The pH of rice bran decreased significantly (P < 0.05) after fermentation, indicating active microbial metabolism and acid production. Lactic acid bacteria (LAB) present in LM-KGRFPS produced organic acids, mainly lactic acid, leading to a drop in pH. Anaerobic fermentation conditions favoured LAB growth and inhibited the development of spoilage microorganisms. A low pH is desirable because it improves preservation quality and prevents the growth of undesirable bacteria such as Clostridium spp. (Queiroz et al., 2018). The final pH values (3.91–4.80) obtained in this study were within the range reported for good-quality silage (Despal et al., 2011; Bernardes et al., 2019).

Lactic acid concentration increased (P < 0.05) with fermentation duration, confirming efficient conversion of soluble carbohydrates into organic acids by LAB. The lactic acid content (49.20–123.17 mg/100 g) was within the range reported by Cherney and Cherney (2015), who indicated that levels above 3% (30 g/kg) are characteristic of well-preserved silage.

 

Table 2: Changes in pH, lactic acid, and Ammonia nitrogen (N-NH₃) contents of rice bran fermented with LM-KGRFPS at different fermentation durations.

Treatment	Initial pH	Final pH	Lactic acid (mg/100 g)	N–NH₃ (mg/100 g)
T0	4.68 ± 0.27	4.68 ±0.27a	49.2 ± 4.37a	10.70 ± 0.39c
T1	4.87 ± 0.05	4.01 ± 0.03b	104.3 ± 6.39b	7.92 ± 1.45a
T2	4.88 ± 0.07	3.91 ± 0.12b	110.8 ± 8.59c	9.71 ± 0.39ab
T3	4.87 ± 0.02	4.02 ± 0.02b	123.2 ± 2.55d	10.10 ± 0.63b
P-value	0.269	0.000	0.000	0.000

 

Values are means ± standard deviation. Mean in the same column and followed by the same superscript letter means no difference (P>0.05) T0 = unfermented; T1 = 6 days; T2 = 12 days; T3 = 18 days.

 

The lowest nitrogen ammonia (N–NH₃) concentration was observed in the 6-day treatment (T1), suggesting limited proteolysis at this stage. Lower N–NH₃ values indicate reduced protein degradation and better preservation of nitrogen compounds (Samadi et al., 2015). According to Despal et al. (2011), ammonia values below 50 g/kg total N reflect high-quality silage. Therefore, fermentation for six days appeared optimal for maintaining nitrogen integrity in rice bran.

Nutrient composition of fermented rice bran

Table 3 presents the nutrient composition of rice bran fermented with LM-KGRFPS for different durations. Fermentation duration had a significant effect (P < 0.05) on the dry matter content of rice bran. Prolonged fermentation for 12 and 18 days resulted in a marked decrease (P < 0.05) in dry matter content compared with shorter fermentation periods. This reduction is attributed to the metabolic activity of microorganisms during fermentation, which produces water as one of its by-products. The accumulation of water over time consequently decreases the dry matter proportion in the substrate. This finding is consistent with the statement of Irawati et al. (2019), who reported that as the fermentation period increases, microorganisms reach their optimal growth phase, utilizing more nutrients from the substrate and generating a higher amount of water through metabolic processes. Therefore, extended fermentation tends to lower dry matter content due to the increased metabolic activity and moisture accumulation within the fermenting material.

Ash content increased (P < 0.05) in samples fermented for 12 and 18 days. The increase could be related to the reduction of organic matter as microorganisms utilized available nutrients, thereby concentrating the mineral fraction. Comparable trends were observed by Superianto et al. (2018), while Sabuna et al. (2024) found that palmyra sap concentration did not significantly affect ash levels in fermented Putak meal (Putak is the inner pith of the Corypha gebanga palm). Crude protein content did not differ significantly (P > 0.05) among treatments, suggesting that microbial protein synthesis did not increase with longer fermentation periods. These results differ from Koni et al. (2025), who reported an increase in crude protein in Putak (Corypha gebanga) fermented with 10–30% palmyra sap, and from Irawati et al. (2019), who found gradual protein enrichment in fermented water hyacinth up to 14 days.

 

Table 3: Nutrient composition of rice bran fermented with LM-KGRFPS at different fermentation durations.

Parameter	T0	T1	T2	T3	P value
Dry matter (%)	60.5 ±0.59bc	61.8 ± 1.75c	56.7 ± 1.92a	57.9 ±0.87ab	0.007
Ash (%)	10.9 ± 0.11a	11.1 ± 0.46a	12.3 ± 0.18b	12.1 ± 0.20b	0.000
Crude protein (%)	7.67 ± 0.27	7.84 ± 0.19	7.26 ± 0.21	7.49 ± 0.23	0.065
Crude fat (%)	1.37 ± 0.25	1.94 ± 1.38	3.10 ± 0.05	2.30 ± 0.19	0.087
Crude fiber (%)	17.9 ± 1.44a	16.7 ± 0.64ab	21.8 ± 0.27c	19.6 ± 1.25bc	0.003

 

Values are means ± standard deviation. Means in the same row and followed by the same superscript letter means no difference (P>0.05). Means in a row with different superscripts differ significantly (P < 0.05). T0 = unfermented; T1 = 6 days; T2 = 12 days; T3 = 18 days.

 

Fermentation duration had no significant effect on crude fat content (P > 0.05). The lack of difference indicates that microorganisms used other carbon sources rather than lipids as energy substrates. In contrast, Sao et al. (2021) observed an increase in crude fat in banana peel fermented with goat rumen fluid.

Crude fiber decreased significantly (P < 0.05) after six days of fermentation (T1). The reduction was attributed to cellulolytic microbial activity in LM-KGRFPS, which degraded cellulose and hemicellulose fractions through enzymatic hydrolysis. Similar reductions were reported by Helda and Sabuna (2012) in goat manure fermented with palmyra sap, and by Koni et al. (2021, 2023) in banana peel and rice bran, respectively.

Overall, fermentation for six days using LM-KGRFPS produced the most favorable results, characterized by lower pH and ammonia levels, increased lactic acid concentration, and reduced crude fiber content while maintaining crude protein stability. These findings indicate that a six-day fermentation period is optimal for improving the nutritional and fermentation quality of rice bran.

CONCLUSION

Fermentation of rice bran with local microorganisms derived from goat rumen fluid and palmyra sap significantly improved its fermentation quality. The six-day fermentation period produced the lowest crude fiber and ammonia contents while maintaining stable crude protein levels and high lactic acid concentration. This duration is recommended as the optimal fermentation time for enhancing the nutritional value and feed quality of rice bran.

ACKNOWLEDGMENT

The authors sincerely thank the Directorate General of Research and Development, Ministry of Higher Education, Science, and Technology, Indonesia, for supporting this study through the Regular Fundamental Research Scheme (Grant No. 193/C3/DT.05.00/PL, Batch II, 2025).

Novelty Statement

This study presents a novel fermentation strategy using a consortium of local microorganisms derived from Kacang goat rumen fluid and palmyra sap to improve the nutritional quality of rice bran. The integration of rumen cellulolytic microbes with fermentative microorganisms from palmyra sap enhances substrate degradation, with a six-day fermentation period identified as optimal for reducing crude fiber and ammonia contents.

Author’s Contribution

TNIK contributed to the development of the research concept, actively participated in data collection, conducted the experimental procedures, performed data analysis, and was the main author of the manuscript. OH contributed to the experimental implementation, particularly in the preparation of LM-KGRFPS and the proximate analysis. SV and TAYF contributed to data analysis and critically reviewed and revised the manuscript for intellectual content.

Generative AI and AI-assisted technology statement

Artificial intelligence tools were used only to assist with grammar correction and sentence editing. The authors affirm that all scientific content, data analysis, interpretation, and conclusions are entirely their own original work.

Conflict of interest

There was no conflict of interest in this research with other parties, both individuals and organizations.

REFERENCES

Association of Official Analytical Chemists (AOAC) (2005). Official methods of analysis. 16th ed. Wansington USA.

Bernardes TF, Gervásio JRS, De Morais G, Casagrande DR (2019). Technical note: A comparison of methods to determine pH in silages. J. Dairy Sci., 102(10): 9039–9042. https://doi.org/10.7202/1059182ar

Chayaningsih H (2006). Identification of lactic acid bacteria from palmyra sap and its application in reducing Salmonella typhimurium and Aspergillus flavus in cocoa beans. Bogor: Sekolah Pasca Sarjana IPB.

Cherney JH, Cherney DJR (2015). Assessing silage quality. Silage Sci Technol., (42): 141–198. https://doi.org/10.2134/agronmonogr42.c4

Debi MR, Wichert BA, Liesegang A (2022). Anaerobic fermentation of rice bran with rumen liquor for reducing their fiber components to use as chicken feed. Heliyon, 8(4): e09275. https://doi.org/10.1016/j.heliyon.2022.e09275

Despal, Permana IG, Safarina SN, Tatra AJ (2011). Addition of water soluble carbohydrate sources prior to ensilage for ramie leaves silage qualities improvement. Media Peternak., 34(1): 69–76. https://doi.org/10.5398/medpet.2011.34.1.69

Ergin S, Gumus H (2020). Silage quality, fermentation dynamics and chemical composition of alfalfa silage prepared with salt and lactic acid bacteria inoculants. Anim. Nutr. Feed Technol., 20: 367–380. https://doi.org/10.5958/0974-181X.2020.00033.5

Ermalia AAU, Sjofjan O, Djunaidi IH (2016). Evaluation nutritients of rice bran second quality fermented using rumen fluid. Bull. Anim. Sci., 40(2): 113–123. https://doi.org/10.21059/buletinpeternak.v40i2.8700

Foenay TAY, Koni TNI, Paga A, Oswilda H, Da-lopez YF (2025). Effect of local microorganisms from Bali cattle rumen fluid and palmyra sap on fiber fractions and nutrient composition of fermented rice bran. Adv. Anim. Vet. Sci., 13(4): 860–865. https://doi.org/10.17582/journal.aavs/2025/13.4.860.865

Helda, Sabuna C. (2012). Fermentation of goat and poultry manure with palmyra sap (Borassus flabellifer) as a feed ingredient for chickens. Partner. 19(1): 112–120.

Ibrahim, Usman (2019). Efficiency of rations with the use of fermented rice bran in growth phase native chickens. Tolis Ilmiah J. Penelit., 1(2): 124–129. https://doi.org/https://doi.org/10.56630/jti.v1i1

Irawati E, Purnamasari E, Arsyad F (2019). Physical and nutritional qualities of Water Hyacinth silage (Eichornia crassipes) with different fermentation lengths. J. Petern., 16(1): 18. https://doi.org/10.24014/jupet.v16i1.3679

Irmayuni E, Nurmila, Sukainah A (2018). Effectiveness of palmyra sap (Borassus flabellifer) as an ingredient for the development of apem cake doungh. J. Pendidik Teknol. Pertan., 4: 170–183. https://doi.org/10.26858/jptp.v4i0.7122

Islam KMS, Elsabagh M, Lv R, Dang HL, Sugino T, Obitsu T (2022). Anaerobic fermentation of rice bran using rumen liquor for desirable chemical changes as animal feed. J. Adv. Vet. Anim. Res., 9(4): 728–735. https://doi.org/10.5455/javar.2022.i642

Kim CH, Park SB, Jeon JJ, Kim H, Kim SH, Hong EC, Kang HK (2017). Effects of dietary supplementation of fermented rice bran (FRB) or fermented broken rice (FBR) on laying performance, egg quality, blood parameter, and cholesterol in egg yolk of Hy-Line Brown laying hens. Korean J. Poult. Sci., 44(4): 235–243. https://doi.org/10.5536/KJPS.2017.44.4.235

Koni TNI, Foenay TAY, Jehemat A (2022). Fermentation characteristics and chemical composition of fermented rice bran with different levels of palmyra sap (Borassus flabellifer). Livest. Res. Rural Dev., 34(10): 88.

Koni TNI, Foenay TAY, Sabuna C, Rohyati E (2021). The nutritional value of fermented banana peels using different levels of palmyra sap. J. Ilm. Petern. Terpadu., 9(1): 62–71. https://doi.org/10.23960/jipt.v9i1.p62-71

Koni TNI, Foenay TAY, Vertigo S (2023). The use of urea and palmyra sap (Borassus flabellifer) on the characteristics and nutrient composition of fermented rice bran. Adv. Anim. Vet. Sci., 11(4): 624–629. https://doi.org/10.17582/journal.aavs/2023/11.4.624.629

Koni TNI, Paga A, Jehemat A, Asrul, Batafor GG, Foenay TAY (2025). Growth performance of Java super chickens fed fermented rice bran during the starter phase. J. Anim. Health Prod., 13(1): 149–153. https://doi.org/10.17582/journal.jahp/2025/13.1.149.153

Liu K, Xu Q, Wang L, Wang J, Guo W, Zhou M (2017). The impact of diet on the composition and relative abundance of rumen microbes in goat. Asian-Australas. J. Anim. Sci., 30: 531–537. https://doi.org/10.5713/ajas.16.0353

Mantut HP, Mauboy R, Boro T (2019). Study of the fermentation time of palmyra sap (Borassus flabeliffer L.) on the abundance and morphological characteristics of microbes. In: Semin Nas Sains dan Tek FST Undana. Kupang; pp. 79–86.

Matias AGS, Araujo GGL, Campos FS, Emerenciano JV (2020). Fermentation profile and nutritional quality of silages composed of cactus pear and manicoba for goat feeding. J. Agric. Sci., 1: 1–9. https://doi.org/ 10.1017/S0021859620000581

Munira S, Nafiu LO, Tasse AM (2016). Performance of cross bred native chickens fed feed substituted with fermented rice bran with different fermentors. J. Ilmu dan Teknol. Petern. Trop., 3(2): 21–29. https://doi.org/10.33772/jitro.v3i2.1683

Odeyemi AT, Oluwole OA, Oso MO (2020). Characterization of bacteria isolated from rumen substrates of goat (Capra aegagrus hircus). Afr. J. Biol. Sci. (South Africa). 2(2): 100–111. https://doi.org/10.33472/AFJBS.2.2.2020.100-111

Queiroz OCM, Ogunade IM, Weinberg Z, Adesogan AT (2018). Silage review: Foodborne pathogens in silage and their mitigation by silage additives. J. Dairy Sci. [Internet]. 101(5): 4132–4142. https://doi.org/10.3168/jds.2017-13901

Sabuna C, Ndolu DAJ, Asrul, Koni TNI (2024). pH, lactic acid, and ammonia changes anaerobic fermentation putak with different levels of palmyra sap. J. Ilmu Petern. dan Vet. Trop., 14(2): 63–69. https://doi.org/10.46549/jipvet.v14i2.412

Samadi, Wajizah S, Usman Y (2015). In vitro study of fermented complete feed by using sago residues as main source diet. Anim. Prod., 17(3): 129. https://doi.org/10.20884/1.anprod.2015.17.3.542

Sao T, Foenay T, Koni TNI (2021). Nutritive content of banana peel flour (Musa paradisiaca) fermented by goat rumen fluid. J. Ilmu Petern. Terap., 4(2): 78–83. https://doi.org/10.25047/jipt.v4i2.2467

Sio S, Bira GF, Batu MS, Pardosi L, Mau RJ, Klau MO, Hoar J (2022). Organoleptic quality and nutrition of rice straw silage utilizing local microorganisms of cattle rumen fluid at different inoculum levels. J. Adv. Vet. Res., 12(1): 36–41.

Superianto S, Harahap AE, Ali A (2018). Nutrition value of cabbage vegetable waste silage with rice bran addition and different duration of fermentation. J. Sain Petern. Indones., 13(2): 172–181.