Improvement of fermentation profile and structural carbohydrate compositions in mixed silages ensiled with fibrolytic enzymes, molasses and Lactobacillus plantarum MTD-1

Figures & data

Table 1. Chemical (g kg^-1 DM) and microbial (log cfu g^–1 FW) composition of tall fescue and hulless-barley straw.

Items	Experiment 1		Experiment 2
	Tall fescue	Hulless-barley straw	Tall fescue	Hulless-barley straw	Molasses
DM, g kg^–1 FW	269	411	317	386	522
CP	62.40	58.30	83.50	70.70	31.20
WSC	264	53.60	210	79.50	654
NDF	533	701	522	672
ADF	302	410	297	387
ADL	41.30	81.10	34.70	70.30
Hemicellulose	231	291	225	285
Cellulose	261	329	262	317
LAB	4.89	2.78	4.55	3.21

DM: dry matter; FW: fresh weight; CP: crude protein; WSC: water soluble carbohydrates; NDF: neutral detergent fibre; ADF: acid detergent fibre; ADL: acid detergent lignin; LAB: lactic acid bacteria; cfu: colony forming unit.

Table 2. Chemical (g kg⁻¹ DM) and microbial (log cfu g⁻¹ FW) compositions of mixed substrates.

Items	Ratios of hulless-barley straw and tall fescue
	100/0	80/20	60/40	40/60
DM, g kg^−1 FW	386	372	358	345
CP	70.70	73.30	75.80	78.40
WSC	79.50	105.60	131.70	157.80
NDF	672	642	612	582
ADF	387	369	351	333
ADL	70.30	63.20	56.10	48.90
Hemicellulose	285	273	261	249
Cellulose	317	306	295	284
LAB	3.21	3.48	3.75	4.01

DM: dry matter; FW: fresh weight; CP: crude protein; WSC: water soluble carbohydrates; NDF: neutral detergent fibre; ADF: acid detergent fibre; ADL: acid detergent lignin; LAB: lactic acid bacteria; cfu: colony forming unit.

Table 3. Fermentation quality of mixed silage of hulless-barley straw and tall fescue with different mixing ratios after 60 days of ensiling (g kg⁻¹ DM).

Items	Ratios of hulless-barley straw and tall fescue				SEM
	100/0	80/20	60/40	40/60
DM, g kg^–1 FW	406^a	381^ab	3620^b	320^c	4.92
pH	4.81^a	4.71^ab	4.57^ab	4.39^b	0.07
NH3–N, g kg^–1 TN	91.50^a	90.60^a	86.10^a	76.20^b	2.24
WSC	8.83^b	9.12^b	10.20^b	12.80^a	0.53
Lactic acid	47.10^b	49.70^b	56.00^ab	61.50^a	2.15
Acetic acid	14.30	13.90	13.50	12.60	0.36
Propionic acid	0.12	0.14	0.16	0.13	0.01
Butyric acid	2.30	2.26	2.19	2.12	0.20
LA/AA	3.30^b	3.62^ab	4.17^ab	4.97^a	0.26

Values in the same row with different superscript letters are significantly different (p < .05).

DM: dry matter; FW: fresh weight; NH₃-N: ammonia nitrogen; TN: total nitrogen; WSC: water soluble carbohydrates; LA/AA: the ratio of lactic acid to acetic acid; SEM: standard error of the mean.

Table 4. Effects of different additives on fermentation characteristics of mixed silages of hulless-barley straw and tall fescue (40/60) during ensiling.

Items	Ensiling days	Treatments						SEM	Significance
		C	E	M	Lp	E + Lp	M + Lp		T	D	T × D
DM, g kg^–1 FW	7	337^b	333^b	362^a	345^b	343^b	361^a	3.36	**	*	ns
	24	330^c	333^c	355^a	341^b	340^b	357^a
	45	328^c	330^c	355^a	343^b	340^b	356^a
	60	329^c	332^c	353^a	342^b	341^b	355^a
pH	7	4.94^a	4.93^a	4.40^c	4.69^b	4.71^b	4.37^c	0.03	**	**	**
	24	4.66^a	4.38^b	4.19^bc	4.28^bc	4.08^c	4.11^c
	45	4.29^a	4.23^ab	4.21^ab	4.17^bc	4.06^c	4.09^c
	60	4.32^a	4.27^a	4.19^ab	4.10^b	4.07^b	4.07^b
Lactic acid, g kg^−1 DM	7	33.10^c	33.60^c	45.70^a	37.40^b	36.90^b	46.20^a	1.57	ns	**	**
	24	41.60^c	53.20^b	64.00^a	62.50^ab	67.70^a	60.20^ab
	45	60.60^b	61.20^b	63.70^a	68.20^a	67.40^a	64.70^a
	60	62.90^b	63.10^b	64.30^a	66.00a	65.20^a	65.80^a
NH3–N, g kg^–1 TN	7	62.90^a	55.80^a	39.90^b	42.80^b	42.10^b	39.50^b	1.44	**	**	*
	24	63.80^a	56.40^b	40.70^c	53.10^b	42.90^c	40.60^c
	45	74.60^a	64.90^b	45.40^c	55.60^b	43.40^c	43.60^c
	60	84.50^a	63.10^b	57.10^c	56.40^c	52.20^d	51.10^d
WSC, g kg^−1 DM	7	53.60^b	58.20^ab	66.90^ab	54.90^b	63.80^ab	71.10^a	2.17	**	**	ns
	24	20.80^c	21.00^c	33.20^b	21.00^c	31.10^b	36.90^a
	45	15.10^c	17.50^c	29.00^ab	17.90^c	25.70^b	32.40^a
	60	11.40^d	16.50^c	26.10^a	15.50^c	23.80^b	29.60^a

Values in the same row with different superscript letters are significantly different (p < .05).

DM: dry matter; FW: fresh weight: NH₃-N: ammonia nitrogen; TN: total nitrogen; WSC: water soluble carbohydrates; C: control; E: fibrolytic enzymes; M: molasses; Lp: Lactobacillus plantarum MTD-1; E + Lp: fibrolytic enzymes+Lactobacillus plantarum MTD-1; M + Lp: molasses+ Lactobacillus plantarum MTD-1; SEM: standard error of the mean; T: additive treatment; D: ensiling days; T × D: interaction of additive treatments and ensiling days. **= p < .01; *= p < .05; NS = not significant (p > .05).

Table 5. Effects of different additives on organic acids and LA/AA ratios of mixed silages of hulless-barley straw and tall fescue (40/60) during ensiling.

Items	Ensiling days	Treatments						SEM	Significance
		C	E	M	Lp	E + Lp	M + Lp		T	D	T × D
Acetic acid, g kg^−1 DM	7	13.30	14.30	14.20	12.30	12.50	12.60	0.229	**	**	NS
	24	15.60^ab	16.70^a	16.10^ab	13.10^c	13.60^bc	14.40^b
	45	16.40^a	16.90^a	16.70^a	13.70^b	13.70^b	14.50^b
	60	16.60^a	16.40^a	16.80^a	13.60^b	13.40^b	13.90^b
Propionic acid, g kg^−1 DM	7	0.05	ND	0.02	ND	0.02	0.01	0.007	NS	**	NS
	24	0.06	0.09	0.04	0.01	0.05	0.05
	45	0.13	0.12	0.14	0.13	0.08	0.12
	60	0.14	0.10	0.12	0.15	0.08	0.11
Butyric acid, g kg^−1 DM	7	1.01^a	1.04^a	0.12^b	0.81^a	0.87^a	0.15^b	0.150	**	**	**
	24	1.72^a	1.22^ab	0.17^c	0.81^b	0.79^b	0.18^c
	45	3.52^a	2.35^a	0.47^c	0.79^b	0.82^b	0.44^c
	60	5.07^a	2.55^b	0.61^c	0.78^c	0.83^c	0.52^c
LA/AA								0.110	**	**	NS
	7	2.49^b	2.36^b	3.22^ab	3.05^ab	2.95^ab	3.74^a
	24	2.66^c	3.19^bc	4.08^b	4.79^a	4.98^a	4.19^a
	45	3.70^b	3.62^b	3.81^b	4.98^a	4.92^a	4.46^a
	60	3.79^b	3.90^b	3.83^b	4.85^a	4.94^a	4.73^a

Values in the same row with different superscript letters are significantly different (p < .05).

DM: dry matter; LA/AA: the ratio of lactic acid to acetic acid; C: control; E: fibrolytic enzymes; M: molasses; Lp: Lactobacillus plantarum MTD-1; E + Lp: fibrolytic enzymes+Lactobacillus plantarum MTD-1; M + Lp: molasses+ Lactobacillus plantarum MTD-1; SEM: standard error of the mean; ND: not detected; T: additive treatment; D: ensiling days; T × D: interaction of additive treatments and ensiling days. **= p < .01; *= p < .05; NS = not significant (p > .05).

Table 6. Effects of different additives on chemical compositions of mixed silages of hulless-barley straw and tall fescue (40/60) after 60 days of ensiling (g kg⁻¹ DM).

Items	Treatments						SEM
	C	E	M	Lp	E + Lp	M + Lp
NDF	679^a	639^b	640^b	643^b	615^c	627^c	4.550
ADF	431^a	407^b	403^b	409^b	392^b	398^b	2.480
ADL	58.20	58.70	56.40	57.90	58.30	58.60	1.400
Hemicellulose	248^a	232^b	237^b	234^b	223^c	229^c	2.300
Cellulose	373^a	348^b	347^b	351^b	334^c	339^c	2.200
NDF/ADL	11.67^a	10.89^b	11.35^ab	11.11^ab	10.55^b	10.70^b	0.083
ADF/ADL	7.41^a	6.93^b	7.15^ab	7.06^ab	6.72^b	6.79^b	0.064
Hemicellulose/ADL	4.26^a	3.95^b	4.20^ab	4.04^b	3.83^b	3.91^b	0.068
Cellulose/ADL	6.41^a	5.93^b	6.15^ab	6.06^ab	5.72^b	5.79^b	0.032

Values in the same row with different superscript letters are significantly different (p < .05).

DM: dry matter; NDF: neutral detergent fibre; ADF: acid detergent fibre; ADL: acid detergent lignin; C: control; E: fibrolytic enzymes; M: molasses; Lp: Lactobacillus plantarum MTD-1; E + Lp: fibrolytic enzymes + Lactobacillus plantarum MTD-1; M + Lp: molasses + Lactobacillus plantarum MTD-1; SEM: standard error of the mean.