Effects of wilting and additives on the fermentation quality and dominant microbial genera in Napier grass silage at different temperatures

doi:10.11686/cyxb2021245

Abstract

Abstract:

Due to the moist， humid climate in South China， the moisture content of harvested Napier grass is high， and the fermentation quality of silage， when ensiled directly， is poor. In this study， Napier grass was wilted （moisture content decreased to 75.11% from 83.19%） and 10% corn flour or 2% sucrose was added， to explore the fermentation characteristics and microbial fermentative community during ensiling at different temperatures （20， 30 and 40 ℃） for 60 days. It was found that temperature had significant effects on the fermentation quality of Napier grass silages. Wilting decreased the water-soluble carbohydrate content of pre-ensiled Napier grass and the fermentation quality of silages， especially when ensiled at 30 ℃， as indicated by a high pH of 5.85， low lactic acid content of 1.56% DM， an acetic acid content of 2.10% DM， and an NH₃-N content of 25.09% TN. The acetic acid production of both the untreated Control and silages with additives increased with increase in ensiling temperature. The gas production of wilted silages ensiled at 20 and 30 ℃ was significantly higher than that at 40 ℃ or for unwilted silages. In addition， the bacterial diversity of Napier grass before ensiling was higher than its silage. After ensiling， the microorganisms found on Napier grass were dominated by the genera Enterobacter and Lactococcus， especially when ensiled at 20 ℃. The relative abundance of Enterococcus in wilted silage at 20 and 30 ℃ was higher than at 40 ℃. In summary， adding corn flour and sucrose can decrease the negative influence of environmental temperature while wilting under humid conditions did not have a positive effect on the fermentation quality of Napier grass silage in South China.

Key words: Napier grass, silage, wilting, storage temperature, bacterial diversity

Jing TIAN, Xiang YIN, Yang FAN, Xin-qin LI, Jian-guo ZHANG. Effects of wilting and additives on the fermentation quality and dominant microbial genera in Napier grass silage at different temperatures[J]. Acta Prataculturae Sinica, 2022, 31(7): 76-84.

Figures/Tables 6

References 29

1	Ashbell G， Weinberg Z G， Hen Y， et al. The effects of temperature on the aerobic stability of wheat and corn silages. Journal of Industrial Microbiology & Biotechnology， 2002， 28（5）： 261-263.
2	Feng L， Kristensen E F， Moset V， et al. Ensiling of tall fescue for biogas production： Effect of storage time， additives and mechanical pretreatment. Energy Sustainable Development， 2018， 47： 143-148.
3	Bernardes T F， Daniel J L P， Adesogan A T， et al. Silage review： Unique challenges of silages made in hot and cold regions. Journal of Dairy Science， 2018， 101（5）： 4001-4019.
4	Moura Z A D， Mauro S E， Dórea J R R， et al. Evaluation of elephant grass silage with the addition of cassava scrapings. Revista Brasileira De Zootecnia， 2010， 39（12）： 2611-2616.
5	Dunière L， Sindou J， Chaucheyras-Durand F， et al. Silage processing and strategies to prevent persistence of undesirable microorganisms. Animal Feed Science and Technology， 2013， 182（1/2/3/4）： 1-15.
6	Oliveira A C， Garcia R， Pires A J V， et al. Farelo de mandioca na ensilagem de capim-elefante： Fracionamento de carboidratos e proteínas e características fermentativas. Revista Brasileira De Saúde E Produção Animal， 2012， 13（4）： 1020-1031.
7	Li D X， Ni K K， Zhang Y C， et al. Fermentation characteristics， chemical composition and microbial community of tropical forage silage under different temperatures. Asian-Australasian Journal of Animal Science， 2019， 32（5）： 665-674.
8	Danner H， Holzer M， Mayrhuber E， et al. Acetic acid increases stability of silage under aerobic conditions. Applied and Environmental Microbiology， 2003， 69（1）： 562-567.
9	Desta S T， Yuan X J， Li J F， et al. Ensiling characteristics， structural and nonstructural carbohydrate composition and enzymatic digestibility of napier grass ensiled with additives. Bioresource Technology， 2016， 221： 447-454.
10	Chen L， Cai Y， Li P， et al. Inoculation of exogenous lactic acid bacteria exerted a limited influence on the silage fermentation and bacterial community compositions of reed canary grass straw on the Qinghai-Tibetan Plateau. Journal of Applied Microbiology， 2020， 129（5）： 1163-1172.
11	Liu Q H， Shao T， Bai Y F. The effect of fibrolytic enzyme， Lactobacillus plantarum and two food antioxidants on the fermentation quality， alpha-tocopherol and beta-carotene of high moisture napier grass silage ensiled at different temperatures. Animal Feed Science and Technology， 2016， 221： 1-11.
12	Ren H， Feng Y， Pei J， et al. Effects of Lactobacillus plantarum additive and temperature on the ensiling quality and microbial community dynamics of cauliflower leaf silages. Bioresource Technology， 2020， 307： 123238.
13	Zhang Q， Yu Z， Wang X G， et al. Effects of inoculants and environmental temperature on fermentation quality and bacterial diversity of alfalfa silage. Animal Science Journal， 2018， 89（8）： 1085-1092.
14	Gulfam A， Guo G， Tajebe S， et al. Characteristics of lactic acid bacteria isolates and their effect on the fermentation quality of napier grass silage at three high temperatures. Journal of the Science of Food and Agriculture， 2017， 97（6）： 1931-1938.
15	Mcdonald P， Playne M J. The buffering constituents of herbage and of silage. Journal of the Science of Food and Agriculture， 1966， 17（6）： 264-265.
16	AOAC （Association of Offcial Analytical Chemistry）. Official methods of analysis （15th edtion）. Arlington （VA）： Association of Official Analytical Chemists， 1990.
17	van Soest P J， Robertsom J B， Lewis B A. Methods for dietary fiber， neutral detergent fiber and non-starch polysaccharides in relation to animal nutrition. Journal of Dairy Science， 1991， 74（10）： 3583-3597.
18	Murphy R P. A method for the extraction of plant samples and the determination of total soluble carbohydrates. Journal of the Science of Food and Agriculture， 1958， 9： 714-717.
19	Yin X， Tian J， Zhang J G. Effects of re-ensiling on the fermentation quality and microbial community of napier grass （Pennisetum purpureum） silage. Journal of the Science of Food and Agriculture， 2021， 101（12）： 5028-5037.
20	Tao X X， Ji C W， Chen S F， et al. Fermentation quality and aerobic stability of napier grass ensiled with citric acid residue and lactic acid bacteria. Tropical Grasslands-Forrajes Tropicales， 2021， 9（1）： 52-59.
21	McDonald P， Henderson A R， Heron S J E. The biochemistry of silage. Marlow： Chalcombe Publications， 1991.
22	van Soest P J， Mertens D R， Deinum B. Preharvest factors influencing quality of conserved forage. Journal of Animal Science， 1978， 47（3）： 712-720.
23	Li X M， Chen F， Wang X K， et al. Impacts of low temperature and ensiling period on the bacterial community of oat silage by SMRT. Microorganisms， 2021， 9（2）： 274.
24	Liu Q H， Zhang J G， Shi S L， et al. The effects of wilting and storage temperatures on the fermentation quality and aerobic stability of stylo silage. Animal Science Journal， 2011， 82（4）： 549-553.
25	Wang C， Nishino N. Effects of storage temperature and ensiling period on fermentation products， aerobic stability and microbial communities of total mixed ration silage. Journal of Applied Microbiology， 2013， 114（6）： 1687-1695.
26	Weinberg Z G， Szakacs G， Ashbell G， et al. The effect of temperature on the ensiling process of corn and wheat. Journal of Applied Microbiology， 2001， 90（4）： 561-566.
27	Zhang J G， Kawamoto H， Cai Y M. Relationships between the addition rates of cellulase or glucose and silage fermentation at different temperatures. Animal Science Journal， 2010， 81（3）： 325-330.
28	Yang H Y， Wang X F， Liu J B， et al. Effects of water-soluble carbohydrate content on silage fermentation of wheat straw. Journal of Bioscience and Bioengineer， 2006， 101： 232-237.
29	Chen D K， Zheng M Y， Guo X， et al. Altering bacterial community： A possible way of lactic acid bacteria inoculants reducing CO₂ production and nutrient loss during fermentation. Bioresource Technology， 2021， 329： 124915.

项目 Items	鲜样 Fresh	晾晒 Wilting
干物质 Dry matter （DM，% FM）	16.81b	24.89a
粗蛋白 Crude protein （CP，% DM）	11.35	12.39
中性洗涤纤维 Neutral detergent fiber （NDF，% DM）	69.30	67.60
酸性洗涤纤维 Acid detergent fiber （ADF，% DM）	48.88	49.70
可溶性碳水化合物 Water-soluble carbohydrate （WSC，% DM）	6.96a	6.03b
pH	5.85b	6.01a
缓冲能Buffering capacity （mE·kg^-1 DM）	172.86b	192.88a
乳酸菌 Lactic acid bacteria （log₁₀ cfu·g^-1 FM）	4.21b	7.36a
好氧细菌 Aerobic bacteria （log₁₀ cfu·g^-1 FM）	6.41b	8.74a
酵母 Yeasts （log₁₀ cfu·g^-1 FM）	3.75b	5.12a
霉菌 Molds （log₁₀ cfu·g^-1 FM）	3.57b	4.32a
梭菌 Clostridia （log₁₀ cfu·g^-1 FM）	1.80	1.84

项目 Items	鲜样 Fresh	晾晒 Wilting
干物质 Dry matter （DM，% FM）	16.81b	24.89a
粗蛋白 Crude protein （CP，% DM）	11.35	12.39
中性洗涤纤维 Neutral detergent fiber （NDF，% DM）	69.30	67.60
酸性洗涤纤维 Acid detergent fiber （ADF，% DM）	48.88	49.70
可溶性碳水化合物 Water-soluble carbohydrate （WSC，% DM）	6.96a	6.03b
pH	5.85b	6.01a
缓冲能Buffering capacity （mE·kg^-1 DM）	172.86b	192.88a
乳酸菌 Lactic acid bacteria （log₁₀ cfu·g^-1 FM）	4.21b	7.36a
好氧细菌 Aerobic bacteria （log₁₀ cfu·g^-1 FM）	6.41b	8.74a
酵母 Yeasts （log₁₀ cfu·g^-1 FM）	3.75b	5.12a
霉菌 Molds （log₁₀ cfu·g^-1 FM）	3.57b	4.32a
梭菌 Clostridia （log₁₀ cfu·g^-1 FM）	1.80	1.84

项目 Item	温度 Temperature （℃）	晾晒和添加物处理Wilting and additives				平均值 Means	标准差 SE	显著性Significance
项目 Item	温度 Temperature （℃）	CK	WS	CS	SS	平均值 Means	标准差 SE	T	WA	T×WA
干物质 Dry matter （% FM）	20	16.29bB	25.50a	22.00a	17.56b	20.34	1.217	NS	**	NS
	30	17.33bA	23.85a	23.28a	17.84b	20.58	0.969
	40	16.17cB	25.93a	23.07b	17.47c	20.66	1.248
pH	20	4.37b	5.44aB	4.24b	3.96cB	4.61	0.222	**	**	**
	30	4.28b	5.85aA	4.14c	4.00dAB	4.47	0.174
	40	4.33b	5.00aC	4.22bc	4.11cA	4.42	0.106
乳酸 Lactic acid （% DM）	20	7.55bB	2.55cB	6.84b	10.35aA	6.82	0.867	**	**	**
	30	10.00aA	1.56cC	7.86b	11.72aA	7.78	1.188
	40	8.25aAB	4.05cA	6.35b	7.86aB	6.63	0.531
乙酸 Acetic acid （% DM）	20	0.99bB	1.35aB	0.71cC	0.56cB	0.90	0.093	**	**	**
	30	1.16bB	2.10aA	0.90bcB	0.74cB	1.23	0.163
	40	1.76aA	1.63aB	1.30bA	0.95cA	1.38	0.105
丁酸 Butyric acid （% DM）	20	0.82a	0.54bB	0.71abC	0.56abB	0.66	0.048	**	**	**
	30	0.83b	1.01aA	0.90abB	0.74bB	0.87	0.036
	40	0.86a	0.46bB	0.93aA	0.95aA	0.80	0.068
氨态氮 Ammonia nitrogen （% TN）	20	14.78a	11.98abB	8.35b	10.37ab	11.37	1.053	*	**	*
	30	11.39b	25.09aA	14.42b	10.45b	15.34	2.045
	40	15.72	13.83B	12.32	8.88	12.69	1.158

项目 Item	温度 Temperature （℃）	晾晒和添加物处理Wilting and additives				平均值 Means	标准差 SE	显著性Significance
项目 Item	温度 Temperature （℃）	CK	WS	CS	SS	平均值 Means	标准差 SE	T	WA	T×WA
干物质 Dry matter （% FM）	20	16.29bB	25.50a	22.00a	17.56b	20.34	1.217	NS	**	NS
	30	17.33bA	23.85a	23.28a	17.84b	20.58	0.969
	40	16.17cB	25.93a	23.07b	17.47c	20.66	1.248
pH	20	4.37b	5.44aB	4.24b	3.96cB	4.61	0.222	**	**	**
	30	4.28b	5.85aA	4.14c	4.00dAB	4.47	0.174
	40	4.33b	5.00aC	4.22bc	4.11cA	4.42	0.106
乳酸 Lactic acid （% DM）	20	7.55bB	2.55cB	6.84b	10.35aA	6.82	0.867	**	**	**
	30	10.00aA	1.56cC	7.86b	11.72aA	7.78	1.188
	40	8.25aAB	4.05cA	6.35b	7.86aB	6.63	0.531
乙酸 Acetic acid （% DM）	20	0.99bB	1.35aB	0.71cC	0.56cB	0.90	0.093	**	**	**
	30	1.16bB	2.10aA	0.90bcB	0.74cB	1.23	0.163
	40	1.76aA	1.63aB	1.30bA	0.95cA	1.38	0.105
丁酸 Butyric acid （% DM）	20	0.82a	0.54bB	0.71abC	0.56abB	0.66	0.048	**	**	**
	30	0.83b	1.01aA	0.90abB	0.74bB	0.87	0.036
	40	0.86a	0.46bB	0.93aA	0.95aA	0.80	0.068
氨态氮 Ammonia nitrogen （% TN）	20	14.78a	11.98abB	8.35b	10.37ab	11.37	1.053	*	**	*
	30	11.39b	25.09aA	14.42b	10.45b	15.34	2.045
	40	15.72	13.83B	12.32	8.88	12.69	1.158

项目 Items	温度 Temperature （℃）	晾晒和添加物处理Wilting and additives				平均值 Means	标准差 SE	显著性Significance
项目 Items	温度 Temperature （℃）	CK	WS	CS	SS	平均值 Means	标准差 SE	T	WA	T×WA
乳酸菌 Lactic acid bacteria （log₁₀ cfu·g^-1 FM）	20	5.91bA	7.44aA	4.01cA	4.18c	5.39	0.428	**	**	**
	30	4.10abB	5.14aB	2.84bB	<2	3.02	0.613
	40	3.00bC	4.49aC	<2	<2	-	-
好氧细菌 Aerobic bacteria （log₁₀ cfu·g^-1 FM）	20	4.99bA	7.43aA	4.49bA	4.09bA	5.05	0.397	**	**	NS
	30	3.85bAB	5.93aB	3.31bB	3.04bB	4.05	0.395
	40	3.59bB	4.68aC	2.10cC	2.26cC	3.16	0.323
酵母 Yeasts （log₁₀ cfu·g^-1 FM）	20	<2	<2	<2	<2	-	-	-	-	-
	30	<2	<2	<2	<2	-	-
	40	<2	<2	<2	<2	-	-
霉菌 Molds （log₁₀ cfu·g^-1 FM）	20	<2	<2	<2	<2	-	-	-	-	-
	30	<2	<2	<2	<2	-	-
	40	<2	<2	<2	<2	-	-