Effects of Mixing Ratio, Microbial Preparation and Packing Density on Fermentation Quality and Nutritional Value of Mixed Silage of Corn Straw and Peanut Vine

ZHANG Xianglun; ZHANG Zheng; LI Junling; YANG Zhaojun; SHENG Qingkai; LIU Xiaomu; ZHAO Guoduo; ZHAO Hongbo

doi:10.12418/CJAN2024.227

2024 , Vol. 36 >Issue 4: 2633 - 2647

DOI: https://doi.org/10.12418/CJAN2024.227

RESEARCH PAPER

Effects of Mixing Ratio, Microbial Preparation and Packing Density on Fermentation Quality and Nutritional Value of Mixed Silage of Corn Straw and Peanut Vine

ZHANG Xianglun ^,¹ ,
ZHANG Zheng ² ,
LI Junling ³ ,
YANG Zhaojun ⁴ ,
SHENG Qingkai ¹ ,
LIU Xiaomu ¹ ,
ZHAO Guoduo ¹ ,
ZHAO Hongbo ^,¹

Expand

¹ Key Laboratory of Livestock and Poultry Multi-Omics of The Ministry of Agriculture and Rural Affairs, Shandong Key Laboratory of Animal Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji’nan 250100, China
² Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Ji’nan 250100, China
³ Shandong Animal Product Quality and Safety Center, Ji’nan 250100, China
⁴ Key Laboratory of Ruminant Nutrition and Feed of Ji’nan, Shandong Meishida Agriculture and Husbandry Technology Limited Company, Ji’nan 251400, China

*professor, E-mail: club1126@163.com

Received date: 2023-11-02

Online published: 2024-04-15

Fold

Abstract

This experiment was conducted to study the effects of mixing ratio, microbial preparation and packing density on fermentation quality and nutritional value of mixed silage of corn straw and peanut vine. This study contained two experiments. Experiment 1 studied the effects of mixing ratio and microbial preparation on fermentation quality and nutritional value of mixed silage of corn straw and peanut vine. The corn straw and peanut vine were mixed based on 5 mixing ratios (4∶0, 3∶1, 2∶2, 1∶3 and 0∶4), with 4 groups in each ratio, involving control group (CON group, spraying sterile physiological saline), Lactobacillus plantarum group (LP group, spraying 1×10⁶ CFU/g Lactobacillus plantarum), Enterococcus faecalis group (EF group, spraying 1×10⁶ CFU/g Enterococcus faecalis) and Lactobacillus plantarum+Enterococcus faecalis group (LP+EF group, spraying 5×10⁵ CFU/g Lactobacillus plantarum+5×10⁵ CFU/g Enterococcus faecalis). Each group contained 3 replicates, and anaerobic fermentation for 60 days. Experiment 2 studied the effects of packing density and microbial preparation on fermentation quality and nutritional value of mixed silage of corn straw and peanut vine. The corn straw and peanut vine were mixed at a ratio of 3∶1, and fermented with different packing densities (300, 450 and 600 kg/m³), with 4 groups in each density (same as experiment 1). Each group contained 3 replicates, and anaerobic fermentation for 60 days. The results of experiment 1 showed as follows: 1) with the increased of peanut vine proportion, the organic matter, neutral detergent fiber and water-soluble carbohydrate contents were significantly decreased (P<0.05), while the crude protein content was significantly increased (P<0.05). Compared with the control group, the neutral detergent fiber content in EF and LP+EF groups was significantly decreased (P<0.05), and the ammonia nitrogen content in EF group was significantly decreased (P<0.05). 2) The mixing ratio had no significant effects on the lactic acid bacteria and mold numbers (P>0.05). Compared with the control group, the lactic acid bacteria number in LP, EF and LP+EF groups was significantly increased (P<0.05), and the mold number in LP+EF group was significantly decreased (P<0.05). 3) The zearalenone content in mixing ratio of 2∶2 group was significantly higher than that in other groups (P<0.05), and the ochratoxin content in mixing ratio of 3∶1 and 2∶2 groups was significantly lower than that in mixing ratio of 4:0 group (P<0.05). Compared with the control group, the zearalenone content in LP+EF group was significantly decreased (P<0.05). 4) The pH in mixing ratio of 2∶2 group was significantly higher than that in other groups (P<0.05), the lactic acid content in mixing ratio of 3∶1 group was significantly higher than that in mixing ratio of 2∶2 group (P<0.05), the acetic acid content in mixing ratio of 3∶1 group was significantly lower than that in other groups (P<0.05), and the butyric acid content in mixing ratio of 3∶1 group was significantly lower than that in mixing ratio of 4∶0 group (P<0.05). Compared with the control group, the pH in LP+EF group was significantly decreased (P<0.05), and the lactic acid content was significantly increased (P<0.05); the acetic acid content in EF group was significantly decreased (P<0.05). The results of experiment 2 showed as follows: 1) the organic matter and crude protein contents in packing density of 600 kg/m³ group were significantly lower than those in packing density of 300 kg/m³ group (P<0.05), and the water-soluble carbohydrate content was significantly higher than that in other groups (P<0.05); with the increased of packing density, the ammonia nitrogen content was significantly decreased (P<0.05). Compared with the control group, the organic content in EF group was significantly increased (P<0.05), and the crude protein content in LP+EF group was significantly increased (P<0.05). 2) The packing density had no significant effects on the lactic acid bacteria and mold numbers (P>0.05). Compared with the control group, the lactic acid bacteria number in LP and LP+EF groups was significantly increased (P<0.05), and the mold number in LP, EF and LP+EF groups was significantly decreased (P<0.05). 3) The zearalenone and fumonin contents in packing density of 450 and 600 kg/m³ groups were significantly higher than those in packing density of 300 kg/m³ group (P<0.05). Compared with the control group, the zearalenone content in LP+EF group was significantly decreased (P<0.05). 4) The packing density had no significant effect on pH (P>0.05). The lactic acid content in packing density of 600 kg/m³ group was significantly higher than that in packing density of 300 kg/m³ group (P<0.05), and the acetic acid and butyric acid contents in packing density of 300 kg/m³ group were significantly higher than those in other groups (P<0.05). In conclusion, comprehensive all indexes, the recommended mixing ratio, microbial preparation and packing density of mixed silage of corn straw and peanut vine are 3∶1, combination of Lactobacillus plantarum and Enterococcus faecalis, 450 to 600 kg/m³, respectively.

Key words： corn straw; peanut vine; mixed silage; microbial preparation; packing density

Cite this article

ZHANG Xianglun , ZHANG Zheng , LI Junling , YANG Zhaojun , SHENG Qingkai , LIU Xiaomu , ZHAO Guoduo , ZHAO Hongbo . Effects of Mixing Ratio, Microbial Preparation and Packing Density on Fermentation Quality and Nutritional Value of Mixed Silage of Corn Straw and Peanut Vine[J]. Chinese Journal of Animal Nutrition, 2024 , 36(4) : 2633 -2647 . DOI: 10.12418/CJAN2024.227

青贮饲料是反刍动物重要的饲料原料,其发酵品质与动物生长密切相关^[1]。近年来,随着我国秸秆饲料化利用进程的持续推进,研究如何利用青贮技术提高秸秆的饲用价值成为关注的热点问题。玉米秸秆是常用的饲料原料,通常以发酵(黄贮)或干玉米秸的形式被用于牛羊养殖,其可溶性糖含量较高,但蛋白质含量偏低^[2]。花生是我国重要的油料与经济作物,其副产物花生秧蛋白质含量高,但含糖量低,不适宜单独作为青贮原料,通常晾晒后用于生产,但受天气等因素影响,晾晒储存期间易滋生霉菌造成养分流失^[3]。将玉米秸秆和花生秧混合青贮,不仅可以促进二者营养互补,而且可以提高发酵品质。近年来,玉米花生带状复合种植模式成为我国农业农村部主推技术之一^[4],此模式下玉米和花生的生长期基本一致,秸秆可同期收获,研究玉米秸秆和花生秧混合青贮发酵技术对于促进秸秆饲料化利用具有重要意义。青贮原料的营养成分、菌剂和压实密度等是生产优质青贮饲料的重要参数。Zeng等^[5]研究了玉米大豆带状复合种植模式下混合青贮效果,发现混合青贮较单一原料青贮明显改变了微生物菌群,提高了乳酸产量和发酵品质。Franco等^[6]在猫尾草和草甸羊茅草混合青贮试验中发现,添加甲酸和乳酸菌、提高压实密度可促进乳酸菌繁殖,提高发酵品质。Guo等^[7]研究报道,添加植物乳杆菌和糖蜜可降低玉米和青稞秸秆混合青贮的pH、乙酸和丁酸产量,改善发酵品质。目前,关于玉米秸秆和花生秧混合青贮的研究报道还较少,混合青贮的适宜发酵参数及营养价值尚不明确,限制了玉米秸秆和花生秧的利用。基于此,本研究以玉米秸秆和花生秧为研究对象,通过研究混合比例、菌剂和压实密度等因素对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响,明确发酵关键技术参数,以期为我国秸秆资源的高效利用提供数据支撑。

1 材料与方法

1.1 试验材料

青贮原料玉米秸秆(玉米品种为甜糯1号,刈割期为乳熟期)和花生秧(花生品种为花育36,刈割期为荚果成熟期)均为山东省农业科学院济阳试验示范基地新鲜刈割的秸秆。选用的青贮发酵袋规格为23 cm×40 cm,聚乙烯材料,装有单向排气阀。青贮发酵瓶为玻璃材质,容积为750 mL,瓶盖内有硅胶圈,密封性好。菌剂:植物乳杆菌,活菌数为1×10¹⁰ CFU/g;粪肠球菌,活菌数为1×10¹¹ CFU/g。

1.2 试验设计

试验分为2部分,试验1研究混合比例和菌剂对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响。试验在2022年7月份开展,将玉米秸秆、花生秧分别切短粉碎至1~2 cm,按不同混合比例(4∶0、3∶1、2∶2、1∶3、0∶4)将二者混合,每个混合比例下设4个组,分别为对照组(CON组,喷洒无菌生理盐水)、植物乳杆菌组(LP组,喷洒1×10⁶ CFU/g植物乳杆菌)、粪肠球菌组(EF组,喷洒1×10⁶ CFU/g粪肠球菌)、植物乳杆菌+粪肠球菌组(LP+EF组,喷洒5×10⁵ CFU/g植物乳杆菌+5×10⁵ CFU/g粪肠球菌),每组设3个重复,每个重复装袋1 kg,封口后用真空泵将袋内空气排出,于室温下避光发酵60 d,之后开袋取样测定常规营养成分含量、微生物数量、霉菌毒素含量及发酵指标。

试验2研究压实密度和菌剂对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响。试验在2022年10月份开展,将玉米秸秆、花生秧分别切短粉碎至1~2 cm,根据试验1结果,将二者按3∶1比例混合,按300、450、600 kg/m³压实密度进行发酵,每个压实密度下设4个组,分别为对照组(喷洒无菌生理盐水)、植物乳杆菌组(LP组,喷洒1×10⁶ CFU/g植物乳杆菌)、粪肠球菌组(EF组,喷洒1×10⁶ CFU/g粪肠球菌)、植物乳杆菌+粪肠球菌组(LP+EF组,喷洒5×10⁵ CFU/g植物乳杆菌+5×10⁵ CFU/g粪肠球菌),每组设3个重复,分别填装于发酵瓶中,封口后置于室温下避光发酵60 d,之后开瓶取样测定常规营养成分含量、微生物数量、霉菌毒素含量及发酵指标。

试验1和试验2的玉米秸秆、花生秧营养成分见含量表1。

表1 玉米秸秆和花生秧营养成分含量(干物质基础)

Table 1 Nutrient contents of corn straw and peanut vine (DM basis)%

项目 Items	干物质(鲜样基础) DM (fresh sample basis)	有机物 OM	粗蛋白质 CP	粗脂肪 EE	中性洗涤纤维 NDF	酸性洗涤纤维 ADF
试验1 Experiment 1
玉米秸秆 Corn straw	23.05	92.68	9.92	3.57	59.66	28.05
花生秧 Peanut vine	21.31	84.64	14.87	2.00	46.76	32.03
试验2 Experiment 2
玉米秸秆 Corn straw	24.42	91.35	9.47	3.28	62.39	29.18
花生秧 Peanut vine	21.76	82.36	13.91	1.98	48.97	33.32

	实测值
	Measured values.

1.3 样本采集及测定指标

1.3.1 营养成分

发酵前和发酵后,分别取各组各重复新鲜样本制备风干样本,干物质(DM)、有机物(OM)、粗蛋白质(CP)和粗脂肪(EE)含量采用AOAC(1990)^[8]方法测定,中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量采用Van Soest等^[9]方法测定,氨态氮(NH₃-N)含量采用苯酚-次氯酸钠比色法^[10]测定,水溶性碳水化合物(WSC)含量采用蒽酮硫酸比色法^[11]测定。

1.3.2 微生物数量

采集各组各重复的新鲜样本20 g,加入180 mL无菌生理盐水,充分搅拌后匀浆,然后将此溶液依次稀释10~10⁷倍。采用平板计数法测定微生物数量,乳酸菌采用MRS琼脂培养基进行计数,霉菌采用马铃薯葡萄糖琼脂培养基进行计数。

1.3.3 霉菌毒素含量

采用间接竞争酶联免疫吸附试验(ELISA)方法测定各组各重复的新鲜样本中霉菌毒素(玉米赤霉烯酮、黄曲霉毒素、呕吐毒素、伏马毒素和赭曲霉毒素)含量,检测步骤参照试剂盒说明书,试剂盒购自山东绿都生物科技有限公司。

1.3.4 发酵指标

发酵结束后,准确称取各组各重复的新鲜样本20 g,加入180 mL蒸馏水,匀浆60 s后用4层纱布过滤,立即使用pH计(HI9025,意大利Hanna Instruments)测定pH。另取新鲜样本20 g,加入180 mL去离子水,匀浆后通过4层纱布和滤纸过滤,所得的液体分装后保存待测。乳酸含量采用对羟基联苯法^[12]测定;采用高效气相色谱仪(GC-2010,日本岛津公司)测定挥发性脂肪酸(VFA)含量,包括乙酸、丙酸和丁酸含量。

1.4 数据统计

数据经Excel 2019整理后,采用SPSS 21.0软件中的单因素方差分析(one-way ANOVA)对各组数据进行统计分析,采用一般线性模型(general linear model,GLM)过程对主效应作用及主效应间的交互作用进行统计分析。多重比较采用Tukey法进行,结果以平均值和均值标准误(SEM)表示,P<0.05为差异显著。

2 结果

2.1 混合比例和菌剂对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响

2.1.1 混合比例和菌剂对玉米秸秆和花生秧混合青贮营养成分含量的影响

混合比例为1∶3、0∶4组在发酵期间颜色变黑、品质差,青贮效果不理想,剔除后对其他组进行分析。由表2可见,随着花生秧比例的提高,混合青贮的OM、NDF、WSC含量显著降低(P<0.05),CP含量显著升高(P<0.05);混合比例为2∶2组的EE含量显著低于混合比例为4∶0组(P<0.05),混合比例为2∶2组的NH₃-N含量显著高于混合比例为4∶0组(P<0.05)。与对照组相比,EF和LP+EF组的NDF含量显著降低(P<0.05),EF组的NH₃-N含量显著降低(P<0.05)。混合比例和菌剂的交互作用对EE含量影响显著(P<0.05)

表2 混合比例和菌剂对玉米秸秆和花生秧混合青贮营养成分含量的影响

Table 2 Effects of mixing ratio and microbial preparation on nutrient content of mixed silage of corn straw and peanut vine

项目 Items	混合比例 Mixing ratio												SEM	混合比例 Mixing ratio			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	4∶0				3∶1				2∶2					混合比例 Mixing ratio				菌剂 Microbial preparation					混合比例 Mixing ratio	菌剂 Microbial prepar- ation	混合比例× 菌剂 Mixing ratio× microbial preparation
	菌剂 Microbial preparation													4∶0	3∶1	2∶2		CON	LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		4∶0	3∶1	2∶2		CON	LP	EF	LP+ EF
有机物 OM/%	91.04^a	90.60^a	91.21^a	91.06^a	89.03^b	88.94^b	89.22^b	89.19^b	86.98^c	87.41^c	87.30^c	87.38^c	0.26	90.98^a	89.09^b	87.27^c	0.08	89.02	88.98	89.24	89.21	0.09	<0.001	0.097	0.185
粗蛋白质 CP/%	11.45^d	11.58^d	11.64^d	11.53^d	12.40^c	12.47^c	12.85^bc	12.80^bc	13.58^a	13.29^ab	13.45^ab	13.42^ab	0.14	11.55^c	12.63^b	13.43^a	0.07	12.47	12.45	12.65	12.58	0.08	<0.001	0.280	0.336
粗脂肪 EE/%	2.68^b	3.31^a	3.41^a	3.39^a	3.28^a	2.95^ab	2.98^ab	3.16^ab	3.01^ab	2.72^b	2.75^b	2.95^ab	0.06	3.20^a	3.09^ab	2.85^b	0.08	2.99	2.99	3.05	3.17	0.09	0.013	0.464	0.021
中性洗涤纤维 NDF/%	51.04^a	49.53^ab	50.37^ab	48.70^abc	47.56^bcd	47.64^bcd	46.23^cde	46.23^cde	44.61^def	43.59^ef	42.39^f	42.45^f	0.50	49.91^a	46.92^b	43.26^c	0.30	47.74^a	46.92^ab	46.33^b	45.79^b	0.34	<0.001	0.004	0.463
酸性洗涤纤维 ADF/%	28.08	27.70	28.12	27.72	28.73	28.80	27.80	27.95	28.97	27.76	27.64	27.60	0.13	27.91	28.32	27.99	0.21	28.59	28.09	27.85	27.76	0.24	0.354	0.095	0.488
氨态氮 NH₃-N/ (g/kg)	1.42^cd	1.41^cd	1.47^cd	1.49^bcd	1.73^abcd	1.45^cd	1.34^d	1.55^bcd	2.14^a	1.95^ab	1.74^abcd	1.87^abc	0.05	1.45^b	1.52^b	1.93^a	0.05	1.76^a	1.60^ab	1.52^b	1.64^ab	0.05	<0.001	0.027	0.215
氨态氮/总氮 NH₃-N/ TN/(g/kg)	77.36^abc	76.28^abc	78.86^abc	80.73^abc	87.17^abc	72.46^bc	65.16^c	75.72^abc	98.68^a	91.74^ab	81.06^abc	87.01^abc	1.82	78.31^b	75.13^b	89.62^a	2.27	87.74^a	80.16^ab	75.03^b	81.15^ab	2.63	<0.001	0.020	0.225
水溶性碳水化合物 WSC/(g/kg)	57.59^a	54.59^ab	54.10^ab	53.80^ab	44.54^bcd	44.39^bcd	44.32^bcd	51.10^abc	40.00^cd	38.11^d	38.13^cd	37.67^d	1.34	55.02^a	46.09^b	38.48^c	1.27	47.38	45.7	45.52	47.52	1.47	<0.001	0.667	0.500

	CON:对照;LP:植物乳杆菌;EF:粪肠球菌;LP+EF:植物乳杆菌+粪肠球菌。同行数据肩标不同小写字母表示差异显著(P<0.05),相同或无字母表示差异不显著(P>0.05)。下表同。
	CON: control; LP: Lactobacillus plantarum; EF: Enterococcus faecalis; LP+EF: Lactobacillus plantarum+Enterococcus faecalis. In the same row, values with different small letter superscripts mean significant difference (P<0.05), while with the same or no letter superscripts mean no significant difference (P>0.05). The same as below.

2.1.2 混合比例和菌剂对玉米秸秆和花生秧混合青贮微生物数量的影响

由表3可见,混合比例对乳酸菌和霉菌数量均无显著影响(P>0.05)。与对照组相比,LP、EF和LP+EF组的乳酸菌数量显著升高(P<0.05),LP+EF组的霉菌数量显著降低(P<0.05)。混合比例和菌剂的交互作用对乳酸菌和霉菌数量无显著影响(P>0.05)。

表3 混合比例和菌剂对玉米秸秆和花生秧混合青贮微生物数量的影响

Table 3 Effects of mixing ratio and microbial preparation on microbial number of mixed silage of corn straw and peanut vinelog₁₀(CFU/mL)

项目 Items	混合比例 Mixing ratio												SEM	混合比例 Mixing ratio			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	4∶0				3∶1				2∶2					混合比例 Mixing ratio				菌剂 Microbial preparation					混合比例 Mixing ratio	菌剂 Microbial prepar- ation	混合比例× 菌剂 Mixing ratio× microbial preparation
	菌剂 Microbial preparation													4∶0	3∶1	2∶2		CON	LP	EF	LP+EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		4∶0	3∶1	2∶2		CON	LP	EF	LP+EF
乳酸菌 Lactic acid bacteria	6.02^b	6.67^b	6.69^ab	6.85^a	6.06^b	7.10^a	6.96^a	7.07^a	6.04^b	7.07^a	6.98^a	7.01^a	0.08	6.56	6.80	6.77	0.08	6.04^b	6.95^a	6.88^a	6.98^a	0.09	0.070	<0.001	0.891
霉菌 Mould	3.09^a	2.79^abc	2.60^abc	2.36^bc	3.06^a	2.91^ab	2.85^abc	2.68^abc	2.99^a	2.80^abc	3.02^a	2.33^c	0.03	2.71	2.88	2.79	0.06	3.05^a	2.83^a	2.82^a	2.46^b	0.03	0.117	<0.001	0.161

2.1.3 混合比例和菌剂对玉米秸秆和花生秧混合青贮霉菌毒素含量的影响

由表4可见,混合比例为2∶2组的玉米赤霉烯酮含量显著高于其他各组(P<0.05);混合比例为3∶1和2∶2组的赭曲霉毒素含量显著低于混合比例为4∶0组(P<0.05),且混合比例为2∶2组显著低于混合比例为3∶1组(P<0.05)。与对照组相比,LP+EF组的玉米赤霉烯酮含量显著降低(P<0.05);菌剂对其他霉菌毒素含量无显著影响(P>0.05)。混合比例和菌剂的交互作用对赭曲霉毒素含量影响显著(P<0.05)。

表4 混合比例和菌剂对玉米秸秆和花生秧混合青贮霉菌毒素含量的影响

Table 4 Effects of mixing ratio and microbial preparation on mycotoxin contents of mixed silage of corn straw and peanut vineμg/kg

项目 Items	混合比例 Mixing ratio												SEM	混合比例 Mixing ratio			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	混合比例 Mixing ratio																						混合比例 Mixing ratio	菌剂 Microbial prepar- ation	混合比例× 菌剂 Mixing ratio× microbial preparation
	4∶0				3∶1				2∶2
	4∶0				3∶1				2∶2					4∶0	3∶1	2∶2		CON	LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		4∶0	3∶1	2∶2		CON	LP	EF	LP+ EF
玉米赤酶烯酮 Zearalenone	13.61^ab	12.72^ab	11.86^ab	12.10^ab	13.03^ab	13.45^ab	12.95^ab	10.12^b	17.66^a	15.82^ab	15.48^ab	12.03^ab	0.46	12.57^b	12.39^b	15.25^a	0.68	14.77^a	13.99^ab	13.43^ab	11.42^b	0.79	0.011	0.037	0.711
黄曲霉毒素 Aflatoxin	0.34	0.35	0.41	0.32	0.43	0.41	0.36	0.35	0.34	0.35	0.39	0.32	0.01	0.36	0.39	0.35	0.02	0.37	0.37	0.39	0.33	0.02	0.193	0.111	0.347
呕吐毒素 Deoxynivalenol	78.40	80.71	80.36	71.02	72.31	74.73	76.94	75.30	79.43	66.06	78.49	78.54	1.37	77.62	74.82	75.63	2.45	76.71	73.83	78.60	74.95	2.83	0.711	0.658	0.402
伏马毒素 Fumonisin	16.92	18.59	19.65	14.72	18.01	18.18	18.24	19.68	19.53	15.63	13.92	16.04	2.73	17.47	18.53	16.28	1.19	18.15	17.47	17.27	16.81	1.38	0.425	0.920	0.535
赭曲霉毒素 Ochratoxin	2.77^ab	3.44^a	2.88^ab	2.27^abc	2.56^ab	2.17^abc	1.74^bc	2.54^ab	1.55^bc	0.99^c	1.55^bc	1.73^bc	0.13	2.84^a	2.25^b	1.46^c	0.15	2.29	2.20	2.06	2.18	0.17	<0.001	0.800	0.043

2.1.4 混合比例和菌剂对玉米秸秆和花生秧混合青贮pH及有机酸含量的影响

由表5可见,混合比例为2∶2组的pH显著高于其他各组(P<0.05),混合比例为3∶1组的乳酸含量显著高于混合比例为2∶2组(P<0.05),混合比例为3∶1组的乙酸含量显著低于其他各组(P<0.05),混合比例为3∶1组的丁酸含量显著低于混合比例为4∶0组(P<0.05)。与对照组相比,LP+EF组的pH显著降低(P<0.05),乳酸含量显著升高(P<0.05);EF组的乙酸含量显著降低(P<0.05)。混合比例和菌剂的交互作用对乳酸和乙酸含量影响显著(P<0.05)。

表5 混合比例和菌剂对玉米秸秆和花生秧混合青贮pH及有机酸含量的影响

Table 5 Effects of mixing ratio and microbial preparation on pH and organic acid contents of mixed silage of corn straw and peanut vine

项目 Items	混合比例 Mixing ratio												SEM	混合比例 Mixing ratio			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	混合比例 Mixing ratio																						混合比例 Mixing ratio	菌剂 Microbial prepar- ation	混合比例× 菌剂 Mixing ratio× microbial preparation
	4∶0				3∶1				2∶2
	4∶0				3∶1				2∶2					4∶0	3∶1	2∶2		CON	LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		4∶0	3∶1	2∶2		CON	LP	EF	LP+ EF
pH	4.11^abcd	3.80^d	3.79^d	3.81^d	4.04^abcd	3.92^cd	3.93^bcd	3.89^cd	4.20^abc	4.25^ab	4.09^abcd	4.26^a	0.03	3.88^b	3.95^b	4.20^a	0.03	4.12^a	3.99^ab	3.99^ab	3.94^b	0.04	<0.001	0.014	0.105
乳酸 Lactic acid/ (g/kg DM)	74.88^abc	78.03^ab	79.43^ab	81.55^a	72.08^abc	84.14^a	77.87^ab	62.11^bc	55.92^c	79.01^ab	69.19^abc	80.76^ab	1.64	74.05^ab	78.47^a	71.22^b	1.89	67.63^b	74.81^ab	75.49^ab	80.39^a	2.18	0.038	0.004	0.002
乙酸 Acetic acid/ (g/kg DM)	48.71^a	26.24^c	28.03^bc	28.81^bc	26.38^c	26.37^c	25.94^c	25.65^c	31.14^bc	34.75^abc	24.54^c	43.21^ab	1.46	32.95^a	26.09^b	33.41^a	1.60	35.41^a	29.12^ab	26.17^b	32.56^ab	1.84	0.005	0.010	0.001
丙酸 Propionic acid/ (g/kg DM)	3.70	3.80	3.73	3.88	4.41	3.85	4.74	3.36	3.84	4.26	3.90	3.71	0.14	3.78	4.09	3.93	0.27	3.98	3.97	4.13	3.65	0.32	0.724	0.752	0.784
丁酸 Butyric acid/ (g/kg DM)	0.056^a	0.052^ab	0.031^abc	0.042^abc	0.023^abc	0.014^c	0.032^abc	0.017^bc	0.054^a	0.037^abc	0.030^abc	0.031^abc	0.003	0.045^a	0.022^b	0.038^ab	0.005	0.044	0.034	0.031	0.030	0.006	0.012	0.342	0.535

2.2 压实密度和菌剂对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响

2.2.1 压实密度和菌剂对玉米秸秆和花生秧混合青贮营养成分含量的影响

由表6可见,压实密度为600 kg/m³组的OM、CP含量显著低于压实密度为300 kg/m³组(P<0.05),WSC含量显著高于其他各组(P<0.05);随着压实密度的增加,混合青贮的NH₃-N含量显著降低(P<0.05)。与对照组相比,EF组的OM含量显著升高(P<0.05),LP+EF组的CP含量显著升高(P<0.05);菌剂对其他营养成分含量无显著影响(P>0.05)。压实密度和菌剂的交互作用对NDF和ADF含量影响显著(P<0.05)。

表6 压实密度和菌剂对玉米秸秆和花生秧混合青贮营养成分的影响

Table 6 Effects of packing density and microbial preparation on nutrient content of mixed silage of corn straw and peanut vine

项目 Items	压实密度 Packing density/(kg/m³)												SEM	压实密度 Packing density/(kg/m³)			SEM	菌剂 Microbial preparation					SEM	P值 P-value
	300				450				600					压实密度 Packing density/(kg/m³)				菌剂 Microbial preparation						压实密度 Packing density	菌剂 Microbial prepar- ation	压实密度× 菌剂 Packing density× microbial preparation
	菌剂 Microbial preparation													300	450	600		CON		LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		300	450	600		CON		LP	EF	LP+ EF
有机物 OM/%	90.21^b	90.34^ab	90.71^a	90.47^ab	90.30^ab	90.05^b	90.47^ab	90.31^ab	90.16^b	90.26^ab	90.20^b	90.29^ab	0.04	90.43^a	90.28^ab	90.23^b	0.05	90.22^b		90.22^b	90.46^a	90.36^ab	0.05	0.011	0.008	0.062
粗蛋白质 CP/%	11.78^ab	11.71^ab	11.68^ab	12.11^a	11.53^ab	11.66^ab	11.68^ab	11.85^ab	11.37^b	11.41^b	11.75^ab	11.65^ab	0.04	11.82^a	11.68^ab	11.54^b	0.06	11.56^b		11.59^ab	11.70^ab	11.87^a	0.07	0.016	0.024	0.432
粗脂肪 EE/%	2.66	2.50	2.47	3.07	2.98	2.95	3.02	2.76	2.65	2.70	3.08	3.14	0.07	2.68	2.93	2.89	0.11	2.76		2.72	2.86	2.99	0.13	0.238	0.469	0.394
中性洗涤纤维 NDF/%	49.99^ab	49.60^ab	51.63^ab	56.55^ab	54.37^ab	51.39^ab	57.22^a	49.32^ab	52.34^ab	51.88^ab	48.66^b	49.35^ab	0.61	51.94	53.08	50.56	0.82	52.23		50.96	52.50	51.74	0.95	0.118	0.680	0.004
酸性洗涤纤维 ADF/%	29.10	28.94	29.35	31.60	31.37	29.68	31.36	28.60	30.12	30.14	28.56	29.20	0.24	29.75	30.25	29.50	0.34	30.20	29.59		29.76	29.80	0.40	0.307	0.736	0.006
氨态氮 NH₃-N/ (g/kg)	1.56^ab	1.53^abc	1.54^abc	1.59^a	1.36^cde	1.44^abcd	1.39^bcde	1.40^bcde	1.28^de	1.23^e	1.28^de	1.25^e	0.02	1.56^a	1.40^b	1.26^c	0.02	1.40	1.40		1.40	1.42	0.02	<0.001	0.955	0.553
氨态氮/总氮 NH₃-N/ TN/(g/kg)	82.92^a	81.49^a	82.42^a	82.26^a	73.91^abc	77.50^ab	74.23^abc	73.99^abc	70.27^bc	67.56^c	68.20^c	67.20^c	1.07	82.27^a	74.91^b	68.31^c	0.89	75.70	75.52		74.95	74.48	1.03	<0.001	0.831	0.666
水溶性碳水化合物 WSC/(g/kg)	56.05^bc	56.71^bc	55.58^bc	58.62^abc	58.44^abc	51.99^c	57.52^bc	62.79^ab	64.88^ab	61.12^abc	65.67^ab	68.74^a	1.09	56.74^b	57.68^b	65.10^a	1.59	59.79	56.61		59.59	63.38	1.83	0.002	0.103	0.865

2.2.2 压实密度和菌剂对玉米秸秆和花生秧混合青贮微生物数量的影响

由表7可见,压实密度对乳酸菌和霉菌数量无显著影响(P<0.05)。与对照组相比,LP和LP+EF组的乳酸菌数量显著升高(P<0.05),LP、EF和LP+EF组的霉菌数量显著降低(P<0.05)。压实密度和菌剂的交互作用对乳酸菌和霉菌数量无显著影响(P>0.05)。

表7 压实密度和菌剂对玉米秸秆和花生秧混合青贮微生物数量的影响

Table 7 Effects of packing density and microbial preparation on microbial number of mixed silage of corn straw and peanut vinelog₁₀(CFU/mL)

项目 Items	压实密度 Packing density/(kg/m³)												SEM	压实密度 Packing density/(kg/m³)			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	300				450				600					压实密度 Packing density/(kg/m³)				菌剂 Microbial preparation					压实密度 Packing density	菌剂 Microbial prepar- ation	压实密度× 菌剂 Packing density× microbial preparation
	菌剂 Microbial preparation													300	450	600		CON	LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		300	450	600		CON	LP	EF	LP+ EF
乳酸菌 Lactic acid bacteria	5.92^c	6.63^abc	6.52^abc	6.71^abc	6.00^c	7.08^abc	6.55^abc	7.23^ab	6.21^bc	7.35^ab	7.43^a	7.25^ab	0.10	6.44	6.71	7.06	0.18	6.04^b	7.02^a	6.83^ab	7.06^a	0.20	0.066	0.006	0.892
霉菌 Mould	3.10^ab	2.44^abc	2.41^abc	2.06^c	3.13^ab	2.62^abc	2.48^abc	2.29^abc	3.28^a	2.78^abc	2.42^abc	2.22^bc	0.06	2.50	2.63	2.67	0.10	3.17^a	2.61^b	2.43^b	2.19^b	0.12	0.451	<0.001	0.978

2.2.3 压实密度和菌剂对玉米秸秆和花生秧混合青贮霉菌毒素含量的影响

由表8可见,压实密度为450和600 kg/m³组的玉米赤霉烯酮和伏马毒素含量显著高于压实密度为300 kg/m³组(P<0.05)。与对照组相比,LP+EF组的玉米赤霉烯酮含量显著降低(P<0.05);菌剂对其他霉菌毒素含量无显著影响(P>0.05)。压实密度和菌剂的交互作用对霉菌毒素含量无显著影响(P>0.05)。

表8 压实密度和菌剂对玉米秸秆和花生秧混合青贮霉菌毒素含量的影响

Table 8 Effects of packing density and microbial preparation on mycotoxin contents of mixed silage of corn straw and peanut vineμg/kg

项目 Items	压实密度 Packing density/(kg/m³)												SEM	压实密度 Packing density/(kg/m³)			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	300				450				600					压实密度 Packing density/(kg/m³)				菌剂 Microbial preparation					压实密度 Packing density	菌剂 Microbial prepar- ation	压实密度× 菌剂 Packing density× microbial preparation
	菌剂 Microbial preparation													300	450	600		CON	LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		300	450	600		CON	LP	EF	LP+ EF
玉米赤酶烯酮 Zearalenone	7.96^cde	7.37^cde	6.33^de	5.16^e	14.51^a	10.96^abcd	13.43^ab	8.86^bcde	14.60^a	13.66^ab	14.10^a	11.66^abc	0.61	6.71^b	11.94^a	13.51^a	0.50	12.36^a	10.66^ab	11.29^a	8.56^b	0.57	<0.001	0.001	0.463
黄曲霉毒素 Aflatoxin	0.33	0.31	0.31	0.35	0.33	0.38	0.37	0.36	0.31	0.36	0.38	0.41	0.01	0.33	0.36	0.37	0.01	0.32	0.35	0.35	0.37	0.02	0.146	0.201	0.600
呕吐毒素 Deoxynivalenol	66.89	62.62	64.54	66.93	67.54	65.93	66.18	62.62	65.13	63.16	66.10	65.05	0.97	65.24	65.57	64.86	1.95	66.52	63.90	65.60	64.87	2.26	0.968	0.866	0.969
伏马毒素 Fumonisin	10.31^bc	8.42^c	11.31^abc	10.18^bc	15.92^abc	16.43^ab	13.82^abc	14.14^abc	18.95^a	14.80^abc	16.45^ab	14.95^abc	0.62	10.06^b	15.08^a	16.29^a	0.76	15.06	13.22	13.86	13.09	0.88	<0.001	0.389	0.484
赭曲霉毒素 Ochratoxin	2.64	2.88	2.62	2.40	2.06	2.41	2.18	2.25	2.72	2.65	2.68	2.61	0.10	2.64	2.22	2.66	0.20	2.47	2.65	2.50	2.42	0.23	0.248	0.912	0.996

2.2.4 压实密度和菌剂对玉米秸秆和花生秧混合青贮pH及有机酸含量的影响

由表9可见,压实密度和菌剂对pH无显著影响(P>0.05);压实密度为600 kg/m³组的乳酸含量显著高于压实密度为300 kg/m³组(P<0.05),压实密度为300 kg/m³组的乙酸和丁酸含量显著高于其他各组(P<0.05)。菌剂对乳酸和VFA含量均无显著影响(P>0.05)。压实密度和菌剂的交互作用对乳酸和丁酸含量影响显著(P<0.05)。

表9 压实密度和菌剂对玉米秸秆和花生秧混合青贮pH及有机酸含量的影响

Table 9 Effects of packing density and microbial preparation on pH and organic acid contents of mixed silage of corn straw and peanut vine

项目 Items	压实密度 Packing density/(kg/m³)												SEM	压实密度 Packing density/(kg/m³)			SEM	菌剂 Microbial preparation				SEM	P值 P-value
	300				450				600					压实密度 Packing density/(kg/m³)				菌剂 Microbial preparation					压实密度 Packing density	菌剂 Microbial prepar- ation	压实密度× 菌剂 Packing density× microbial preparation
	菌剂 Microbial preparation													300	450	600		CON	LP	EF	LP+ EF
	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF	CON	LP	EF	LP+ EF		300	450	600		CON	LP	EF	LP+ EF
pH	3.77	3.75	3.74	3.76	3.74	3.73	3.75	3.77	3.77	3.74	3.75	3.76	0.01	3.76	3.75	3.76	0.01	3.76	3.74	3.75	3.76	0.01	0.579	0.191	0.491
乳酸 Lactic acid/ (g/kg DM)	58.64^b	59.01^b	58.25^b	63.34^ab	60.70^ab	63.97^ab	63.53^ab	60.86^ab	64.86^ab	63.56^ab	67.37^a	62.75^ab	0.56	59.81^b	62.27^ab	64.63^a	0.70	61.40	62.18	63.05	62.32	0.81	<0.001	0.559	0.028
乙酸 Acetic acid/ (g/kg DM)	24.26^a	22.75^abc	23.07^abc	23.31^ab	20.65^bc	22.27^abc	21.04^abc	21.35^abc	21.04^abc	21.27^abc	21.65^abc	19.86^c	0.26	23.35^a	21.33^b	20.96^b	0.34	21.98	22.10	21.92	21.51	0.39	<0.001	0.732	0.249
丙酸 Propionic acid/ (g/kg DM)	3.65	3.76	3.50	3.28	3.32	3.35	3.14	3.20	3.65	3.15	3.00	3.27	0.08	3.55	3.25	3.27	0.15	3.54	3.42	3.21	3.25	0.17	0.297	0.499	0.900
丁酸 Butyric acid/ (g/kg DM)	0.034^ab	0.016^bc	0.036^a	0.031^ab	0.023^abc	0.025^abc	0.020^abc	0.012^c	0.023^abc	0.018^abc	0.022^abc	0.022^abc	0.001	0.029^a	0.020^b	0.021^b	0.002	0.027	0.019	0.026	0.021	0.002	0.004	0.077	0.020

3 讨论

3.1 混合比例和菌剂对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响

3.1.1 混合比例和菌剂对玉米秸秆和花生秧混合青贮营养成分含量的影响

青贮是指在密闭厌氧条件下,利用乳酸菌发酵产生乳酸,抑制其他腐败微生物的活动,从而达到饲料长期保存的目的。青贮原料的营养成分、添加菌剂等参数是影响发酵品质的重要因素^[13]。本研究发现,当玉米秸秆和花生秧混合比例为1∶3、0∶4时,青贮颜色变黑、发生腐败,进行了剔除,说明在本试验条件下该混合比例不适宜制作混合青贮。青贮的营养成分含量是评价青贮质量的一项重要指标。本研究发现,随着花生秧比例的提高,混合青贮的OM、EE、NDF、WSC含量降低,CP含量升高。营养成分分析表明,与玉米秸秆相比,花生秧的OM、EE、NDF、WSC含量偏低^[14],因此混合青贮的营养成分变化与玉米秸秆和花生秧混合比例有关。NH₃-N主要是由微生物分解利用植物的蛋白质和氨基酸产生,NH₃-N含量反映青贮中蛋白质的降解程度^[5]。本研究发现,花生秧比例为50%时,混合青贮的NH₃-N含量显著提高,说明高比例花生秧不利于饲料中蛋白质的保存;单独添加粪肠球菌和联合添加植物乳杆菌和粪肠球菌降低了NDF含量,单独添加粪肠球菌降低了NH₃-N含量。已有报道表明,乳酸菌剂能够促进青贮中有机酸的产生,水解植物的可消化细胞壁部分,因此造成纤维的分解^[15]。而且乳酸菌可以竞争性地抑制腐败微生物对青贮中蛋白质的分解作用,从而降低NH₃-N含量。

3.1.2 混合比例和菌剂对玉米秸秆和花生秧混合青贮微生物数量的影响

微生物分析表明,各混合比例组的乳酸菌和霉菌数量差异不显著。与玉米秸秆相比,花生秧中的WSC含量较低^[14],而WSC是乳酸菌发酵的重要底物,本研究结果说明花生秧占比50%以下时不影响混合青贮中乳酸菌的生长。添加乳酸菌制剂可以提高混合青贮中乳酸菌数量,以植物乳杆菌和粪肠球菌联合添加组最高,同时霉菌数量显著降低。这说明额外添加乳酸菌制剂可以促进混合青贮中的乳酸菌快速繁殖,进而抑制霉菌等有害微生物的生长,这与前人的研究结果^[16-17]一致。

3.1.3 混合比例和菌剂对玉米秸秆和花生秧混合青贮霉菌毒素含量的影响

饲料中霉菌毒素是由各种真菌产生的有毒的次级代谢产物,包括玉米赤霉烯酮、黄曲霉毒素、呕吐毒素、伏马毒素、赭曲霉毒素等,其对动物生长及繁殖带来不利因素^[18]。本试验结果表明,混合青贮中各项霉菌毒素含量均未超出国家《饲料卫生标准》^[19]的要求,说明玉米秸秆和花生秧混合青贮可用于畜禽生产。研究发现,混合比例和菌剂对混合青贮的玉米赤霉烯酮、伏马毒素、赭曲霉毒素含量影响显著。玉米赤霉烯酮和伏马毒素是由镰刀菌属真菌产生的次级代谢产物,主要污染玉米、小麦等;赭曲霉毒素是由曲霉属和青霉属的多种真菌产生的一种霉菌毒素,主要污染谷物、花生等作物^[20]。本试验结果表明,随着花生秧比例的提高,玉米赤霉烯酮含量升高,但赭曲霉毒素含量降低,推测混合发酵过程中添加高比例花生秧可能导致镰刀菌的滋生,曲霉和青霉等生长受抑制,造成霉菌毒素含量发生变化。本研究还发现,添加乳酸菌制剂可降低混合青贮中的玉米赤霉烯酮含量,以植物乳杆菌和粪肠球菌联合添加组最低,较对照组降低22.68%。利用微生物降解饲料中霉菌毒素一直是研究的热点,已有研究报道植物乳杆菌、乳球菌等对玉米赤霉烯酮具有较好的降解和吸附能力^[21-22],这与本研究结果一致,说明添加乳酸菌制剂可减少青贮过程中霉菌毒素的产生。

3.1.4 混合比例和菌剂对玉米秸秆和花生秧混合青贮pH及有机酸含量的影响

青贮饲料的pH和有机酸含量是评价发酵品质的重要指标。本研究发现,当花生秧比例提高至50%时,混合青贮的pH升高,乳酸含量降低。乳酸主要是由乳酸菌发酵葡萄糖产生,其含量通常与发酵品质呈正相关^[16]。已有报道表明,花生秧的WSC含量低于玉米秸秆^[13],随着花生秧比例的提高,青贮过程中乳酸菌可用的发酵底物逐渐减少,造成乳酸产量的降低,pH升高。乙酸是由异型发酵乳酸菌发酵产生,异型发酵的速度慢、易造成营养损失;丁酸是由腐败菌和酪酸菌分解蛋白质、葡萄糖等产生,与青贮饲料的品质呈负相关^[16]。本试验中,花生秧比例为25%时混合青贮的乙酸和丁酸含量最低,继续提高花生秧比例乙酸和丁酸含量升高,说明适当提高混合青贮中花生秧比例可能促进乳酸菌的同型发酵,抑制腐败微生物的作用。菌剂方面,添加乳酸菌制剂可以降低混合青贮的pH,提高乳酸产量,降低乙酸产量,以植物乳杆菌和粪肠球菌联合添加效果最佳,这与前人的研究报道^[3]一致,植物乳杆菌和粪肠球菌均为同型发酵乳酸菌,联合添加可以促进玉米秸秆和花生秧混合青贮的同型发酵过程。

3.2 压实密度和菌剂对玉米秸秆和花生秧混合青贮发酵品质和营养价值的影响

3.2.1 压实密度和菌剂对玉米秸秆和花生秧混合青贮营养成分的影响

目前,关于压实密度对青贮营养成分的研究结果尚存在争议。Blajman等^[23]报道,将压实密度由450 kg/m³提高至550 kg/m³后,玉米青贮的DM和NH₃-N含量降低,对CP和粗纤维含量无显著影响。Gallo等^[24]研究发现,压实密度(364和503 kg/m³)对玉米青贮的DM、OM、CP、粗纤维等含量均无显著影响。路桂聪等^[25]报道,提高压实密度(700~900 kg/m³)降低了狼尾草青贮的CP含量,提高了NDF含量。由于各研究采用的青贮原料和压实密度不一致,造成研究结果存在差异。本研究发现,随着压实密度的升高,混合青贮的OM、CP和NH₃-N含量降低,WSC含量提高。压实密度升高后,植物细胞的破碎率提高,营养物质流出增加,乳酸菌利用营养物质进行发酵后,抑制了腐败微生物的作用,降低了NH₃-N的产生。菌剂方面,单独添加粪肠球菌和联合添加植物乳杆菌和粪肠球菌分别提高了青贮的OM和CP含量。已有报道表明,乳酸菌剂能够促进青贮中有机酸的产生,水解植物的可消化细胞壁部分,因此造成纤维的分解^[15]。而且乳酸菌可以竞争性地抑制腐败微生物对青贮中蛋白质的分解作用,从而降低NH₃-N含量。

3.2.2 压实密度和菌剂对玉米秸秆和花生秧混合青贮微生物数量的影响

本研究发现,压实密度对混合青贮中乳酸菌和霉菌数量均无显著影响,但添加乳酸菌剂可提高不同压实密度下青贮的乳酸菌数量,并能同步减少霉菌数量。这说明提高混合青贮中乳酸菌数量主要还是以添加乳酸菌剂为主,增加压实密度并不影响乳酸菌的繁殖^[26],而且添加乳酸菌制剂可以有效促进乳酸菌繁殖,进而达到抑制霉菌滋生的作用^[16]。

3.2.3 压实密度和菌剂对玉米秸秆和花生秧混合青贮霉菌毒素含量的影响

本研究发现,压实密度由300 kg/m³提高至450 kg/m³以上后,混合青贮的玉米赤霉烯酮和伏马毒素含量均升高,但压实密度为450和600 kg/m³组之间无显著差异。与本研究不一致的是,Gallo等^[24]发现玉米青贮的黄曲霉毒素B₁、伏马毒素含量不受压实密度(364和503 kg/m³)的影响。王旭哲^[27]发现提高压实密度(500和600 kg/m³)可一定程度上降低全株玉米青贮中玉米赤霉烯酮、伏马毒素含量。玉米赤霉烯酮和伏马毒素均由镰刀菌属真菌产生,本研究及前人研究均发现,提高压实密度并不影响青贮中霉菌数量^[15,26]。因此本研究推测,提高压实密度虽然对霉菌数量无影响,但高密度下混合青贮的营养物质含量更丰富,可能一定程度上促进霉菌代谢产生毒素,继续提高压实密度后因受空气含量、乳酸菌繁殖等影响,霉菌代谢过程受抑制,因此霉菌毒素含量维持不变。本研究还发现,添加乳酸菌制剂可降低青贮中玉米赤霉烯酮含量,以植物乳杆菌和粪肠球菌联合添加组最低,较对照组降低30.74%。这与试验1的研究结果基本一致,进一步验证了添加乳酸菌制剂可以减少霉菌毒素产生。

3.2.4 压实密度和菌剂对玉米秸秆和花生秧混合青贮pH及有机酸含量的影响

本研究发现,随着压实密度的增加,混合青贮的乳酸含量升高,乙酸和丁酸含量逐渐降低,这与前人研究结果类似。这说明增加压实密度能够减少青贮中残存的氧气,进而缩短青贮过程中的有氧呼吸阶段,促进乳酸菌的厌氧发酵^[23,28]。菌剂方面,添加乳酸菌制剂不影响混合青贮pH及有机酸含量,说明添加乳酸菌制剂对不同压实密度下的玉米秸秆和花生秧混贮发酵品质无显著影响。

4 结论

① 玉米秸秆和花生秧混合青贮可以提高青贮营养价值,减少霉菌毒素产生,适宜混合比例为3∶1。添加菌剂能够改善混合青贮的发酵品质,以植物乳杆菌和粪肠球菌联合添加为宜。

② 适宜压实密度可以减少玉米秸秆和花生秧混合青贮的营养成分损失,改善发酵品质,以450~600 kg/m³为宜。添加菌剂能够提高混合青贮的营养价值,减少霉菌毒素产生,以植物乳杆菌和粪肠球菌联合添加为宜。

③ 综合的各项指标,推荐玉米秸秆和花生秧混合青贮的混合比例为3∶1,菌剂为植物乳杆菌和粪肠球菌联合添加,压实密度为450~600 kg/m³。

References

Publishing order | Descend order by publishing year | Descend order by cited within

[1]	BORREANI G, TABACCO E, SCHMIDT R J, et al. Silage review:factors affecting dry matter and quality losses in silages[J]. Journal of Dairy Science, 2018, 101(5):3952-3979. DOI

[2]	WANG Y, ZHOU W, WANG C, et al. Effect on the ensilage performance and microbial community of adding Neolamarckia cadamba leaves to corn stalks[J]. Microbial Biotechnology, 2020, 13(5):1502-1514. DOI

[3]	WANG Q D, WANG R X, WANG C Y, et al. Effects of cellulase and Lactobacillus plantarum on fermentation quality,chemical composition,and microbial community of mixed silage of whole-plant corn and peanut vines[J]. Applied Biochemistry and Biotechnology, 2022, 194(6):2465-2480. DOI

[4]

中华人民共和国农业农村部. 农业农村部办公厅关于推介发布2021年农业主推技术的通知[EB/OL].(2021-11-04) [2023-06-01]. http://www.moa.gov.cn/nybgb/2021/202107/202111/t20211104_6381244.htm

Ministry of Agriculture and Rural Affairs of the People’s Republic of China. Notice of the general office of the ministry of agriculture and rural affairs on the introduction and release of the main agricultural push technology in 2021[EB/OL].(2021-11-04) [2023-06-01]. http://www.moa.gov.cn/nybgb/2021/202107/202111/t20211104_6381244.htmin Chinese)

[5]	ZENG T R, LI X L, GUAN H, et al. Dynamic microbial diversity and fermentation quality of the mixed silage of corn and soybean grown in strip intercropping system[J]. Bioresource Technology, 2020, 313:123655. DOI

[6]	FRANCO M, TAPIO I, PIRTTINIEMI J, et al. Fermentation quality and bacterial ecology of grass silage modulated by additive treatments,extent of compaction and soil contamination[J]. Fermentation, 2022, 8(4):156. DOI

[7]	GUO G, YUAN X J, LI L X, et al. Effects of fibrolytic enzymes,molasses and lactic acid bacteria on fermentation quality of mixed silage of corn and hulless-barely straw in the Tibetan Plateau[J]. Grassland Science, 2014, 60(4):240-246. DOI

[8]	AOAC. Official methods of analysis[M].15th ed. Artington: Association of Official Analytical Chemists, 1990.

[9]	VAN SOEST P J, ROBERTSON J B, LEWIS B A. Methods for dietary fiber,neutral detergent fiber,and nonstarch polysaccharides in relation to animal nutrition[J]. Journal of Dairy Science, 1991, 74(10):3583-3597. DOI

[10]	BRODERICK G A, KANG J H. Automated simultaneous determination of ammonia and total amino acids in ruminal fluid and in vitro media[J]. Journal of Dairy Science, 1980, 63(1):64-75. DOI

[11]	OWENS V N, ALBRECHT K A, MUCK R E, et al. Protein degradation and fermentation characteristics of red clover and alfalfa silage harvested with varying levels of total nonstructural carbohydrates[J]. Crop Science, 1999, 39(6):1873-1880. DOI

[12]	BARKER S B, SUMMERSON W H. The colorimetric determination of lactic acid in biological material[J]. Journal of Biological Chemistry, 1941, 138(2):535-554. DOI

[13]	MUCK R E, NADEAU E M G, MCALLISTER T A, et al. Silage review:recent advances and future uses of silage additives[J]. Journal of Dairy Science, 2018, 101(5):3980-4000. DOI

[14]	QIN M Z, SHEN Y X. Effect of application of a bacteria inoculant and wheat bran on fermentation quality of peanut vine ensiled alone or with corn stover[J]. Journal of Integrative Agriculture, 2013, 12(3):556-560. DOI

[15]	LARSEN S U, HJORT-GREGERSEN K, VAZIFEHKHORAN A H, et al. Co-ensiling of straw with sugar beet leaves increases the methane yield from straw[J]. Bioresource Technology, 2017, 245(Pt A):106-115. DOI PMID

[16]	张相伦, 游伟, 赵红波, 等. 乳酸菌制剂对全株玉米青贮品质及营养成分的影响[J]. 动物营养学报, 2018, 30(1):336-342. ZHANG X L, YOU W, ZHAO H B, et al. Effects of lactic acid bacteria preparation on quality and nutrient composition of whole corn silage[J]. Chinese Journal of Animal Nutrition, 2018, 30(1):336-342. (in Chinese)

[17]	MU L, XIE Z, HU L X, et al. Cellulase interacts with Lactobacillus plantarum to affect chemical composition,bacterial communities,and aerobic stability in mixed silage of high-moisture amaranth and rice straw[J]. Bioresource Technology, 2020, 315:123772. DOI

[18]	TOLOSA J, RODRÍGUEZ-CARRASCO Y, RUIZ M J, et al. Multi-mycotoxin occurrence in feed, metabolism and carry-over to animal-derived food products:a review[J]. Food and Chemical Toxicology, 2021, 158:112661. DOI

[19]

中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会. 饲料卫生标准:GB 13078—2017[S]. 北京: 中国标准出版社, 2017.

General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China, Standardization Administration of the People’s Republic of China. Hygienical standard for feeds:GB 13078—2017[S]. Beijing: Standards Press of China, 2017. (in Chinese)

[20]	AGRIOPOULOU S, STAMATELOPOULOU E, VARZAKAS T. Advances in occurrence,importance,and mycotoxin control strategies:prevention and detoxification in foods[J]. Foods, 2020, 9(2):137. DOI

[21]	ROGOWSKA A, POMASTOWSKI P, WALCZAK J, et al. Investigation of zearalenone adsorption and biotransformation by microorganisms cultured under cellular stress conditions[J]. Toxins, 2019, 11(8):463. DOI

[22]	ADUNPHATCHARAPHON S, PETCHKONGKAEW A, VISESSANGUAN W. In vitro mechanism assessment of zearalenone removal by plant-derived Lactobacillus plantarum BCC 47723[J]. Toxins, 2021, 13(4):286. DOI

[23]	BLAJMAN J E, SIGNORINI M L, VINDEROLA G, et al. Impact of native spray-dried lactic acid bacteria,packing density and wilting time on fermentation characteristics of experimental maize and lucerne silages[J]. Grass and Forage Science, 2022, 77(1):66-78. DOI

[24]	GALLO A, BERNARDES T F, COPANI G, et al. Effect of inoculation with Lactobacillus buchneri LB1819 and Lactococcus lactis O224 on fermentation and mycotoxin production in maize silage compacted at different densities[J]. Animal Feed Science and Technology, 2018, 246:36-45. DOI

[25]	路桂聪, 许辉, 玉永雄, 等. 不同添加物和密度对杂交狼尾草青贮效果的影响[J]. 草业科学, 2021, 38(11):2191-2199. LU G C, XU H, YU Y X, et al. Effects of different additives and densities on silage quality of hybrid Pennisetum[J]. Pratacultural Science, 2021, 38(11):2191-2199. (in Chinese)

[26]	HE Q, ZHOU W, CHEN X Y, et al. Chemical and bacterial composition of Broussonetia papyrifera leaves ensiled at two ensiling densities with or without Lactobacillus plantarum[J]. Journal of Cleaner Production, 2021, 329:129792. DOI

[27]	王旭哲. 紧实度及收获期对全株玉米青贮品质及霉菌毒素的影响研究[D].博士学位论文. 石河子: 石河子大学, 2019. WANG X Z. Effect of compaction and harvest stage on quality and mycotoxin of whole-plant corn silage[D].Ph.D.Thesis. Shihezi: Shihezi University, 2019. (in Chinese)

[28]	王旭哲, 张凡凡, 唐开婷, 等. 密度对玉米青贮发酵品质、微生物和有氧稳定性的影响[J]. 中国草地学报, 2018, 40(1):80-86. WANG X Z, ZHANG F F, TANG K T, et al. Effect of density on fermentation quality,microbial quantity and aerobic stability of corn silage[J]. Chinese Journal of Grassland, 2018, 40(1):80-86. (in Chinese)

Options

Outlines

模态框（Modal）标题