Citation of this paper

Effects of rice distillers’ by-product supplementation on feed intake, nutrient digestibility and nitrogen retention of Bach Thao goats

Nguyen Binh Truong^1,2 and Truong Thanh Trung³

¹ An Giang University, An Giang, Vietnam
nbtruong@agu.edu.vn
² Vietnam National University Ho Chi Minh City, Vietnam
³ Can Tho University, Can Tho, Vietnam

Abstract

This study aimed to determine the effects of rice distillers’ by-product (RDB) levels in the diets on feed intake, nutrient digestibility, and nitrogen retention of female Bach Thao goats. Four goats at approximately 5 months of age and 12.0±1.84 kg live weight. A Latin square design experiment was conducted with 4 treatments and four periods (21 days/period). Four treatments were 5, 10, 15, and 20% (%DM) corresponding to RDB5, RDB10, RDB15, and RDB20, respectively.

The result showed that DMI/BW (%) gradually increased from 3.21 to 3.35, 3.60 and 3.56 corresponding to RDB5, RDB10, RDB15, and RDB20, respectively. The metabolizable energy intake of RDB15 was higher than (p<0.05) RDB5 and RDB10 but it was similar to RDB20 treatment. The nutrient digestibility was proportionally increased followed by increasing levels of RDB in the diets, due to digestible nutrients being significantly different for treatments. Nitrogen retention value was different (p>0.05) among treatments. However, the daily weight gain (g/per/day) had a gradually increased trend (p>0.05) from RDB5 to RDB15 and decreased at RDB20 (121- 176, and 143 g/per/day, respectively).

It was concluded that increasing RDB from 5 to 20% in diets improved feed and nutrient intake, nutrient digestibility, and daily weight gain of goats. A level of 15% RDB in the diet could be promising in the application for female Bach Thao goats from 5 to 8 months of age.

Keywords: rice distillers’ by-product, digestibility, goat

Introduction

The purpose of goat production takes advantage of local by-products for total low raising costs.

According to Preston et al. (2021a), in order two respond to the emergencies of climate change and loss of biodiversity, ruminant feeding systems in the tropics should be based on trees and shrubs complemented by carbohydrate-rich byproducts of agro-industrial crops. In a previous study on the use of roughage on Bach Thao goats, Phong and Thu (2018) suggested that the optimum level of cabbage waste (Brassica oleracea) replacement for Para grass is up to 50%. Likewise, Operculia turpethum vines was a cheap and abundant local feed resource and the same may be incorporated in diets for goats up to levels of 25% to 35%, without any adverse effects on daily weight gain reported by Dat et al (2018).

However, the feed supplement is necessary for a goat. The waste after distilling the alcohol derived by yeast fermentation of sticky rice or “Hem” is traditionally used by farmers. The rice distillers’ by-product (RDB) is produced in large amounts in some places in the Mekong Delta. The RDB is the waste derived from the artisan production of alcohol from rice with high protein and energy content but low dry matter reported by Manh et al. (2009). In another study, fed at low levels (4%) to a ruminant diet reported by Preston et al. (2021b) who consider that RDB improves animal healthy and increases the production of propionic acid in the rumen, and indirectly improves ruminant animal performance.

We hypothesized that the levels of RDB could affect feed intake, nutrient digestibility and nitrogen retention of goats.

Materials and methods

Location

The experiment was carried out in the experimental farm of the Animal and veterinary science Department, An Giang University from January to April 2023.

The chemical composition of experimental diets was analyzed at laboratory E205 of the Faculty of Animal Sciences, Agriculture University of Can Tho University.

Animals and experimental design

The average body weight of the female Bach Thao goats used in this experiment was 12.0±1.84 kg at 5 months old. Treatments were applied using Latin Square design (4x4) with 2 weeks for adaptation and 1 week for data collection per period.

The four treatments were supplied RDB at 5%, 10%, 15%, and 20% dry matter. The dietary CP content was calculated at the suggestion of Thu (2017). The compositions of diets are shown in Table 1.

Table 1. Ingredients composition used in the experiment
Ingredients (%DM)	RDB5	RDB10	RDB15	RDB20

Rice distillers’ by-product	5.00	10.0	15.0	20.0
Coconut meat waste	5.00	5.00	5.00	5.00
Cabbage waste	13.3	12.6	11.8	11.1
Operculina turpethumvines	75.5	71.1	66.8	62.4
Urea	1.00	1.00	1.00	1.00
Premix	0.200	0.30	0.40	0.50

The levels of supplemental urea increased crude protein for reference according to Thu (2017), the premix accounted for 2.0% of the feed supplement from RDB and coconut meat waste. Cabbage waste ratio for roughage is 15%. RDB, coconut meat waste, cabbage waste and Operculia turpethum vines were purchased, collected, and cut around Long Xuyen City, An Giang province. The mix included: RDB, coconut meat waste, urea, and premix were fed twice at 7:00 am and 1:00 pm. The cabbage waste was fed twice at 8:00 am and 2:00 pm. Operculia turpethum vines was supplied ad libitum.

Feed offered, refusals and feces were analyzed for dry matter (DM), organic matter (OM) and crude protein (CP), and ash contents according to the procedures of AOAC (1990). However, neutral detergent fiber (NDF) and acid detergent fiber (ADF) were analyzed by the procedure of Van Soest et al. (1991).

This study was 4 experimental periods. Each period was 3 weeks with 2 weeks for adaptation to the new treatment followed by a week collection of feces to determine digestibility coefficients (McDonald et al 2010). The goats were weighed on three consecutive days at the beginning and end of each experimental period.

The data were analyzed using the ANOVA Linear Model (GLM) of Minitab Reference Manual Release 20. (Minitab, 2021). Tukey's pairwise comparisons (p<0.05) were applied to determine differences between treatments.

Results

Chemical composition of feeds

The feed nutrients in this study were within the range of values reported by Phong and Thu (2018), Dat et al (2018) and Manh et al (2009).

Table 2. Chemical composition of feeds (% DM basis) used in the experiment
Feeds	DM %	% in DM
Feeds	DM %	OM	CP	NDF	ADF

Rice distillers’ by-product	12.1	97.1	27.4	28.1	16.2
Coconut meat waste	42.4	99.2	3.69	58.1	41.5
Cabbage waste	6.19	87.8	17.2	34.7	23.9
Operculina turpethumvines	12.8	88.8	16.7	45.3	34.5
Urea	99.6	-	286	-	-
DM: dry matter, OM: organic matter, CP: crude protein, NDF: neutral detergent fiber, ADF: acid detergent fiber

Feed and nutrient intakes

The nutrient intake and metabolism energy were increased and DM intake per body weight was improved, all with curvilinear trends, as the offer level of RDB was increased (Table 3: Figures 1).

Table 3. Effect of RDB levels on feed and nutrient intakes of goat in this study
Item	Treatments				SEM	p
Item	RDB5	RDB10	RDB15	RDB20	SEM	p

Feeds intake, g DM/animal/day
Rice distillers’ by-product	30.4^d	62.4^c	104^b	129^a	4.51	0.001
Coconut meat waste	30.9^b	31.8^b	35.2^a	33.0^b	0.43	0.002
Cabbage waste	64.2	65.6	69.3	60.7	2.58	0.23
Operculina turpethum vines	455	428	449	386	15.20	0.06
Urea	6.01^c	6.18^bc	6.84^a	6.46^ab	0.08	0.002
Premix	1.20^d	1.86^c	2.74^b	3.21^a	0.1	0.001
Nutrients intake, g DM/animal/day
DM	588	596	667	619	17.10	0.06
DM/BW, %	3.21	3.35	3.60	3.56	0.12	0.17
OM	520	529	594	554	15.30	0.05
CP	122^c	130b^c	146^a	141^ab	2.37	0.001
NDF	246	240	267	240	8.27	0.21
ADF	181	172	191	170	7.05	0.243
Output, animal/day
Feces, gDM	205	182	192	176	6.61	0.08
Urin, g	2,647	2,673	2,949	2,681	71.40	0.07
DM: dry matter, OM: organic matter, CP: crude protein, NDF: neutral detergent fiber, ADF: acid detergent fiber, a, b, c values with different superscript letters within one row are significantly different at the level of 5%

Figure 1. DM intake per body weight is increased with a curvilinear
trend as the feeding level of RDB was increased

Digestibility

Increasing the RDB levels in the diet affected the digestibility of dry matter, organic matter, and neutral detergent fiber. As a result, this increased the digestible nutrients (Table 4). The positive effects on nutrient digestibility value can be expected as supplementations with RDB increased feed intake in this study.

Table 4. Apparent nutrient digestibility and digestible nutrient of goat in different treatments.
Item	Treatments				SEM	p
Item	RDB5	RDB10	RDB15	RDB20	SEM	p

Nutrient digestibility, %
DM	64.9^b	69.7^a	71.2^a	71.6^a	0.656	0.001
OM	65.6^b	70.3^a	71.8^a	72.4^a	0.765	0.003
CP	72.3	72.8	74.1	73.6	0.952	0.572
NDF	55.0^b	59.3^ab	61.7^a	59.5^ab	1.040	0.020
ADF	52.7	57.7	60.7	57.3	2.010	0.140
Digestible nutrient, g/animal/day
DM	383^c	414b^c	474^a	443^ab	11.60	0.007
OM	343^c	371b^c	427^a	401^ab	10.80	0.007
CP	88.1^c	94.6b^c	108^a	104^ab	2.390	0.004
NDF	136	143	164	143	5.870	0.067
ADF	96.6	99.2	116	97.7	4.580	0.074
DM: dry matter,OM: organic matter, CP: crude protein, NDF: neutral detergent fiber, ADF: acid detergent fiber, ^{a, b, c}values with different superscript letters within one row are significantly different at the level of 5%

Discussion

Nitrogen retention and daily weight gain

Table 5. Nitrogen retention, and daily weight gain of goat in the present study
Item	Treatments				SEM	p
Item	RDB5	RDB10	RDB15	RDB20	SEM	p

Nitrogen (N), g/animal/day
N _intake	19.5^c	20.8^bc	23.3^a	22.5^ab	0.38	0.001
N _fecal	5.37	5.68	6.034	5.92	0.20	0.2
N _urin	7.66^b	8.45^b	10.4^a	8.97^ab	0.35	0.01
N _retention	6.43	6.68	6.88	7.59	0.36	0.24
N _retention,g/BW^0.75/day	0.693	0.737	0.758	0.85	0.04	0.09
Body weight change, g/animal/day
Initial _{body weight}, kg	17.4	17.2	16.8	16.8	0.37	0.67
Final _{body weight}, kg	19.9	19.8	20.5	19.8	0.21	0.17
DWG, g	121	125	176	143	13.40	0.09
DM: dry matter,OM: organic matter, CP: crude protein, NDF: neutral detergent fiber, ADF: acid detergent fiber, a, b, c values with different superscript letters within one row are significantly different at the level of 5%


Figure 2. Daily weight gain was increased with a curvilinear trend as the feeding level of RDB was increased	Figure 3. Feed conversion was improved with a curvilinear trend as the feeding level of RDB was increased

According to Sivilai et al. (2018), rice distillers’ by-products was postulated that the beneficial effects of these supplements on nutrient utilization were probably associated with the presence of β-glucan in the cell walls of the residual yeast, acting as a source of prebiotics. The beneficial effects of RDB in increased nutrient digestibility from rumen fermentation. Increasing RDB levels in the Bach Thao goat diets led to improve DM, OM and NDF digestibility. Besides, CP digestibility tended to respond positively to the intake of RDB. Daily weight gain tended to increase with increasing rice distillers’ by-products.

In this study, the difference in digestible DM, OM, and CP could be explained that RDB is a solution carbohydrate source fermented and distilled resulting in improved CP levels and DM consumption. DM, OM and CP digestible and digestibility were great for goats but shout not be supplied more than 15% of the diet.

Conclusion

It was concluded that increasing RDB supplement levels in the diets of female Bach Thao goat improved feed and nutrient intake, feed conversion, and daily weight gain.
A level of 15% RDB in the diet would be recommended to implement performance studies in the goat for better local by-product souces utilization for farmers.

References

AOAC (Association of Official Analytical Chemists) 1990 Official methods of analysis (15th edition). Washington, DC, 1: 69-90.

Dat H Q, Quyen N T K, Linh N T, Hieu T V, Hung L T and Wilson M A 2018 Effect of Operculia turpethum replaces Brachiariamutica in rations on the Bach Thao goat's growth. The 4th International Asian-Australasian Dairy Goat Conference. Proceedings. October 17-19, 2018 Tra Vinh, Viet Nam. P: 283-288.

Manh L H, Dung N N X, Kinh L V, Binh T C, Hang B P T and Phuoc T V 2009 Composition and nutritive value of rice distillers’ by-product (hem) for small-holder pig production. Livestock Researchfor Rural Development. Volume 21, Article #224. http://www.lrrd.org/lrrd21/12/manh21224.htm

McDonald P, Edwards R A, Greenhalgh J F D, Morgan C A, Sinclair L A and Wilkinson R G 2010 Animal Nutrition (7^th edition). Longman Scientific and Technical. N.Y. USA.

Minitab 2021 Minitab reference manual release 20.3, Minitab Inc.

Phong L V and Thu N V 2018 Effects of levels of cabbage waste (Brassica oleracea) replacement to Para grass (Brachiaria mutica) in diets on feed utilization, nutrient digestibility and rumen environment of male Bach Thao goat in Mekong delta of Vietnam. The 4th International Asian-Australasian Dairy Goat Conference. Proceedings. October 17-19, 2018 Tra Vinh, Viet Nam. P: 270-277.

Preston T R, Leng R A and Gomez M E 2021a Adapting systems of livestock production to be compatible with global commitments to restore the health of planet Earth; ecosystems that remove atmospheric carbon and provide, food, feed and renewable energy. Livestock Research for Rural Development. Volume 33, Article #31. http://www.lrrd.org/lrrd33/3/Editorial3331.html

Preston T R, Leng R A, Garcia Y, Binh P T, Inthapanya S and Gomez M E 2021b Yeast (Saccharomyces cerevisiae) fermentation of polished rice or cassava root produces a feed supplement with the capacity to modify rumen fermentation, reduce emissions of methane and improve growth rate and feed conversion. Livestock Research for Rural Development. Volume 33, Article #61. http://www.lrrd.org/lrrd33/5/3361preston.html

Sivilai B, Preston T R, Hang D T and Linh N Q 2018 Effect of a 4% dietary concentration of rice distillers’ byproduct, or of brewers' grains, on growth rate and feed conversion during pregnancy and lactation of native Moo Lath gilts and their progeny. Livestock Researchfor Rural Development. Article #20. Link: http://www.lrrd.org/lrrd30/1/lert30020.html

Thu N V 2017 The effects of dietary crude protein levels on nutrient digestibility, nitrogen retention, rumen environment and microbial nitrogen synthesis of growing female Bach Thao goats in Vietnam. Modern Agricultural Science and Technology. Volume 3, No. 5-6, pp. 30-36. DOI: 10.15341/mast(2375-9402)/03.03.2017/006

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 animal nutrition. Journal of Dairy Science, 74: 3583-3598. Link: https://doi.org/10.3168/jds.S0022-0302(91)78551-2