Effects of Lactobacillus paracasei on the Quality and Bacterial Diversity of Silage Alfalfa After Aerobic Exposure

doi:10.13560/j.cnki.biotech.bull.1985.2021-0717

Abstract

Abstract:

16S rRNA high-throughput sequencing technology was used to detect the dynamic variations of bacterial community in the silage alfalfa after aerobic exposure,aiming to provide a basis for the dynamic changes of bacterial diversity in the aerobic exposure of silage alfalfa and the inoculation of lactic acid bacteria to prevent aerobic deterioration. Alfalfa silage without inoculation（CON）and inoculated with Lactobacillus paracasei（LCP）were fermented for 56 d,and the dynamic changes of fermentation quality and bacterial diversity of the silage at 0,7,and 14 d after aerobic exposure. The results showed that aerobic exposure resulted in the increase of the pH of uninoculated silage alfalfa and the decrease of the lactic acid content. Compared with CON,inoculation of L. paracasei had a smaller increase in pH but higher lactic acid content during aerobic exposure（P<0.05）. CON was mainly composed of Lactobacillus,Enterobacter,and Enterococcus,among which the abundance of Enterobacter and Enterococcus gradually decreased;the LCP group was mainly dominated by Lactobacillus,and its abundance gradually decreased. In addition,abundance of Acetobacter appeared after 14 d of aerobic exposure. Correlation analysis revealed that Lactobacillus was negatively correlated with pH（P<0.05）. Enterobacter,Enterococcus,Wierella,Cedecea,Sporolactobacillus were positively correlated with pH. Acetobacter was negatively correlated with lactic acid and acetic acid（P<0.05）. In summary,this study found that Acetobacter was abundant in the silage alfalfa exposed to long-term aerobic exposure,reducing the content of lactic acid and acetic acid. Inoculation of L. paracasei may increase the abundance of Lactobacillus and reduce the abundance of Acetobacter in long-term（14 d）aerobic exposure. Therefore,inoculation of silage alfalfa with L. paracasei can improve the quality of short-term aerobic exposure silage,enhance its aerobic stability,and slow down aerobic deterioration.

Key words: silage alfalfa, aerobic exposure, Lactobacillus paracasei, bacterial diversity

WANG Qi, WU Zhi-xuan, CHEN Zhong-ling, WU Bai-yi-la, HU Zong-fu, NIU Hua-xin. Effects of Lactobacillus paracasei on the Quality and Bacterial Diversity of Silage Alfalfa After Aerobic Exposure[J]. Biotechnology Bulletin, 2021, 37(9): 77-85.

Figures/Tables 11

References 19

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组别Group	鲜样Fresh sample	PO0		PO7		PO14		SEM	ANOVA
组别Group	鲜样Fresh sample	CON	LCP	CON	LCP	CON	LCP	SEM	I	S	I×S
DM /%	23.92	20.85	22.26	20.57	21.49	20.79	21.72	0.48	**	NS	NS
pH	6.27	5.46	4.55	5.44	4.74	6.43	4.83	0.01	**	**	**
LAB/（log₁₀ CFU/g FM）	5.53	7.22	7.68	6.56	7.34	5.38	6.28	0.06	**	**	**
Yeasts/（log₁₀CFU/g FM）	3.76	3.28	2.56	4.46	3.90	7.13	6.07	0.09	**	**	**
Molds/（log₁₀ CFU/g FM）	3.92	2.80	<2.00	3.08	3.51	6.24	4.68	0.09	—	—	—
LA/（g·kg^-1 DM）		31.67	48.61	11.56	26.85	4.73	15.49	1.04	**	**	**
AA/（g·kg^-1 DM）		18.32	15.88	11.55	12.52	7.43	10.41	0.63	**	**	**
PA/（g·kg^-1 DM）		3.75	2.64	1.56	1.24	0.82	0.68	0.28	*	**	NS
BA/（g·kg^-1 DM）		1.43	0.45	2.01	1.48	3.21	2.61	0.04	**	**	**

组别Group	鲜样Fresh sample	PO0		PO7		PO14		SEM	ANOVA
组别Group	鲜样Fresh sample	CON	LCP	CON	LCP	CON	LCP	SEM	I	S	I×S
DM /%	23.92	20.85	22.26	20.57	21.49	20.79	21.72	0.48	**	NS	NS
pH	6.27	5.46	4.55	5.44	4.74	6.43	4.83	0.01	**	**	**
LAB/（log₁₀ CFU/g FM）	5.53	7.22	7.68	6.56	7.34	5.38	6.28	0.06	**	**	**
Yeasts/（log₁₀CFU/g FM）	3.76	3.28	2.56	4.46	3.90	7.13	6.07	0.09	**	**	**
Molds/（log₁₀ CFU/g FM）	3.92	2.80	<2.00	3.08	3.51	6.24	4.68	0.09	—	—	—
LA/（g·kg^-1 DM）		31.67	48.61	11.56	26.85	4.73	15.49	1.04	**	**	**
AA/（g·kg^-1 DM）		18.32	15.88	11.55	12.52	7.43	10.41	0.63	**	**	**
PA/（g·kg^-1 DM）		3.75	2.64	1.56	1.24	0.82	0.68	0.28	*	**	NS
BA/（g·kg^-1 DM）		1.43	0.45	2.01	1.48	3.21	2.61	0.04	**	**	**

Sample\Estimators	Sobs	Shannon	Simpson	Ace	Chao
CONPO0_1	43.67	2.12	0.18	53.25	49.37
CONPO7_1	59.33	1.98	0.22	71.99	67.07
CONPO14_1	62.00	1.69	0.33	79.05	74.23
LCPPO0_1	43.00	1.21	0.41	79.80	55.789
LCPPO7_1	47.00	1.08	0.49	76.73	60.91
LCPPO14_1	44.00	1.33	0.38	92.71	67.73
SEM	2.66	0.10	0.03	5.65	3.22
P	0.092	0.001	0.004	0.552	0.263

Sample\Estimators	Sobs	Shannon	Simpson	Ace	Chao
CONPO0_1	43.67	2.12	0.18	53.25	49.37
CONPO7_1	59.33	1.98	0.22	71.99	67.07
CONPO14_1	62.00	1.69	0.33	79.05	74.23
LCPPO0_1	43.00	1.21	0.41	79.80	55.789
LCPPO7_1	47.00	1.08	0.49	76.73	60.91
LCPPO14_1	44.00	1.33	0.38	92.71	67.73
SEM	2.66	0.10	0.03	5.65	3.22
P	0.092	0.001	0.004	0.552	0.263

Genus	OTU	CONPO0	CONPO7	CONPO14	LCPPO0	LCPPO7	LCPPO14
Acetobacter	OTU53	0	0.03	34.99	0	0.27	18.37
Lactobacillus	OTU123	0	0	0	4.08	0.35	0.46
Pediococcus	OTU58	0	0	0	0.52	1.2	0.13
Weissella	OTU26	4.17	3.71	1.58	0	0.01	0
Komagataeibacter	OTU125	0	0		0	0	5.58
Cedecea	OTU45	2.02	1.81	3.29	0	0	0
Lactobacillus	OTU127	0.65	0.48	0.19	0	0.01	2.29
Lactobacillus	OTU133	0.64	1.7	0.84	9.2	17.81	21.23
Lactobacillus	OTU41	2.63	34.63	28.38		0.18	3.97
Lysinibacillus	OTU57	0	0	3.81	0	0	0
ALCPaligenes	OTU35	0	0	0.36	0	0	0.03
Sporolactobacillus	OTU29	1.1	0.12	0.03	0	0	0
Lactobacillus	OTU27	8.52	10.71	8.47	0.06	0.05	0.13
Lactobacillus	OTU153	0.32		0.05	52.99	65.39	42.11
Garciella	OTU11	7.74	0	0	0	0	0
Lactobacillus	OTU54	4.3	3.17	2.54	0	0	0
Enterobacter	OTU38	32.58	19.35	6.59	0.94	1.19	0.43
Enterococcus	OTU21	13.12	6.84	3.19	0.04	0.03	0.03
Lactobacillus	OTU104	3.74	1.19	0.27	26.65	9.07	3.81
Lactobacillus	OTU76	1.23	8.69	1.47	0.07	0.05	0.06
Lactobacillus	OTU148	0	0	0	1.98	1.74	0.2
Lactobacillus	OTU115	0.01	0.01	0	2.54	1.69	0.85
Lactobacillus	OTU71	2.95	4.36	1.68	0	0	0
Enterococcus	OTU14	3.79	1.34	0.67	0	0	0