Fermentation quality and aerobic stability of mulberry silage prepared with lactic acid bacteria and propionic acid

The objective of this study was to examine the fermentation quality and aerobic stability of mulberry (Morus alba L.) silage prepared with lactic acid bacteria (LAB) and propionic acid (PA). The selected LAB strains Lactobacillus (L.) plantarum LC365281 (L1) and L. brevis LC365282 (L2), and commercial inoculant strains L. plantarum Gaofuji (GF) and L. buchneri Fresh (FR), and PA were used as additives for silage preparation. Silage treatments were designed as control, L1, L2, GF, FR, PA, PA + L1, PA + L2, PA + GF, or PA + FR. After 30 days of ensiling, the fermentation quality of silages treated with PA + L1 was improved, with a lower (p < 0.05) pH and NH₃‐N content than those of other treatments. During the aerobic exposure, the PA + LAB‐treated silages displayed an aerobic stability with stable pH value and lactic acid content. The results confirm that L. plantarum L1 and PA were the best additive combination for ensiling mulberry.     

Isolating and evaluating lactic acid bacteria strains for effectiveness on silage quality at low temperatures on the Tibetan Plateau

Four lactic acid bacteria (LAB) strains isolated from straw silages on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) at different temperatures (10°C, 15°C and 25°C) were studied. These LAB isolates were evaluated using the acids production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All the isolates (M1, LM8, LO7 and LOG9) could grow at 5‐20°C, pH 3.5‐7.0 and NaCl (3.0%, 6.5%). Strains M1, LM8, LO7 and LOG9 were identified as Lactobacillus plantarum, L. coryniformis, Pediococcus pentosaceus and P. acidilactici, respectively, by sequencing 16S ribosomal DNA. The four isolates were added to Italian ryegrass for ensiling for 30 days at various temperatures. Compared with the corresponding control, inoculating with isolates M1, LM8 and LO7 could improve the silage quality of Italian ryegrass at low temperatures, indicated by significantly (P < 0.05) higher lactic acid (LA) contents and ratios of lactic acid/acetic acid (LA/AA), and significantly (P < 0.05) lower pH and ammonia nitrogen/total nitrogen (AN/TN). Compared with other isolates, LM8 performed better at 10°C and 15°C, indicated by the higher (P < 0.05) LA content and ratio of LA/AA, and the lower (P < 0.05) pH and AN/TN.     

Effect of grape pomace on fermentation quality and aerobic stability of sweet sorghum silage

The objective of this study was to evaluate the effect of grape pomace (GP) with different adding levels (0%, 5%, 10% and 15%, fresh matter basis), alone (GP‐LAB) or in combine with an inoculant LAB (GP+LAB), on the fermentation quality and aerobic stability of sweet sorghum silage. After 90 days of ensiling in vacuumized mini‐silos, silages were subject to a 7‐day aerobic stability test, in which chemical, microbial and polyphenol composition were measured. In the GP‐LAB group, adding GP decreased (P < 0.05) concentrations of water‐soluble carbohydrate (WSC) and butyric acid in silage. In the GP+LAB group, adding GP increased (P < 0.05) concentrations of lactic acid, WSC and crude protein, decreased (P < 0.05) final pH value, NH₃‐N ratio and butyric acid concentration in silage. Polyphenol level was reduced (P < 0.05) after silage fermentation. During aerobic exposure, the fungi count, pH value and silage temperature increased (P < 0.05), the levels of lactic acid, acetic acid and polyphenols (quercetin 3‐O‐glucoside and quercetin 3‐O‐glucuronid) decreased (P < 0.05) in silage. GP+LAB treated silage had a lag phase for aerobic spoilage. When the fermentation products, microbial counts, chemical and polyphenol composition were considered, the use of 10% GP+LAB at ensiling could provide a valuable source for improved fermentation quality and aerobic stability of sweet sorghum silage.     

Effect of ensiling whole crop oat with lucerne in different ratios on fermentation quality,aerobic stability and in vitro digestibility on the Tibetan plateau

The objective of this study was to determine the effect of ensiling different ratios of whole crop oat to lucerne on fermentation quality, aerobic stability and in vitro digestibility of silage on the Tibetan plateau. Four experimental treatments were produced varying in the ratio of forages on a fresh matter (FM) basis: 1) 100% oat (control, dry matter (DM) content: 317 g/kg), 2) 90% oat + 10% lucerne (OL10, DM content: 316 g/kg), 3) 80% oat+ 20% lucerne (OL20, DM content: 317 g/kg) and 4) 70% oat+ 30% lucerne (OL30, DM content: 318 g/kg). All treatments were packed into laboratory‐scale silos and ensiled for 60 days and then subjected to an aerobic stability test for 15 days. Further, the four experimental treatments were incubated in vitro with buffered rumen fluid to study the nutrient digestibility. All silages were well preserved with low pH and NH₃‐N contents, and high lactic acid contents and V‐scores (evaluation of silage quality). Increasing the lucerne proportion increased (p < 0.05) crude protein (CP) content of silage, whereas neutral (NDF) and acid (ADF) detergent fibre contents were not affected. Under aerobic conditions, the control silage showed higher (p < 0.05) yeast counts (>10⁵ cfu/g FM) followed by OL10 silage, and OL10 silage improved aerobic stability for 74 h. OL20 and OL30 silages showed fewer (p < 0.05) yeasts (<10⁵ cfu/g FM) and markedly (p < 0.05) improved the aerobic stability (>360 h). After 48‐h incubation, OL30 silage increased (p < 0.05) in vitro dry matter digestibility (IVDMD) and neutral detergent fibre digestibility (IVNDFD) compared with the control silage. These results suggest that replacing oat with lucerne had no unfavourable effects on fermentation quality of silage, but improved CP content, aerobic stability IVDMD and IVNDFD. OL30 silage was the best among the three mixed silages.     

添加酶和乳酸菌制剂对西藏苇状羊茅和箭筈豌豆混合青贮发酵品质的影响

为评价添加酶、乳酸菌制剂和酶+乳酸菌制剂对苇状羊茅与箭筈豌豆(7∶3)混合青贮发酵品质的影响,试验设对照组(C)、酶制剂(E)、乳酸菌制剂(LAB)和酶+乳酸菌制剂(E+LAB)4个处理,3个重复,青贮后第7,24,60天开窖取样,测定青贮饲料发酵品质。结果表明,与对照组相比,添加酶或乳酸菌制剂能有效地改善混合青贮发酵品质,组合添加进一步提高了乳酸含量和降低了pH值。与对照组和单独添加乳酸菌组相比,在整个青贮过程中无论是酶单独添加还是组合添加都显示较高的乙酸和总挥发性脂肪酸含量,最高的水溶性碳水化合物含量和最低的氨态氮/总氮。这说明酶和乳酸菌制剂组合添加对改善青贮发酵品质有叠加效应。综上所述,酶和乳酸菌制剂组合添加能更好的改善苇状羊茅和箭筈豌豆混合青贮的发酵品质。     

添加糖蜜和乳酸菌制剂对西藏青稞秸秆和多年生黑麦草混合青贮发酵品质的影响

为探究不同添加剂对青稞秸秆与多年生黑麦草(4∶6)混合青贮发酵品质的影响,试验设对照组(C)、乳酸菌制剂组(LAB)、糖蜜组(M)、乳酸菌制剂+糖蜜组(LAB+M)4个处理,青贮后第7, 24和45天打开,测定青贮发酵品质。结果表明,添加乳酸菌制剂加速了青贮早期乳酸发酵进程,但由于底物不足,青贮后期丁酸含量和氨态氮/总氮值有所升高;添加糖蜜补充了发酵底物,促进了乳酸发酵,显著(P<0.05)提高了乳酸含量,降低了pH值(P<0.05),从而有效地抑制了有害微生物的活性,减少了丙酸和丁酸的生成。乳酸菌制剂+糖蜜组与单独添加乳酸菌制剂组相比显著提高了青贮发酵品质, 但与单独添加糖蜜组相比差异不显著,表明发酵底物不足是限制青稞秸秆与多年生黑麦草混合青贮发酵品质的主要因素。     

Effect of varying fermentation conditions with ensiling period and inoculum on photosynthetic pigments and phytol content in Italian ryegrass (Lolium multiflorum Lam.) silage

This study aimed to investigate the effect of an ensiling period (Experiment 1) and adding lactic acid bacteria (LAB, Experiment 2) on the changes in carotenoid, chlorophyll, and phytol in ensiled Italian ryegrass (IR, Lolium multiflorum Lam.). In Experiment 1, the IR herbage ensiled into plastic bags was analyzed for the contents of photosynthetic pigments and phytol over a 5‐week period. During the ensiling process, the β‐carotene content decreased (p < .05), whereas the lutein content did not change. Although the chlorophyll content decreased (p < .05) after ensiling, the phytol content barely changed until week 5. In Experiment 2, IR herbage was ensiled without additive, as a Control, or with LAB for 60 days. The pH was lower (p < .05) and lactic acid content was higher (p < .05) for the LAB silage than for the Control. The chlorophyll content in silage was not affected by the LAB; however, the β‐carotene content was higher (p < .05) for the LAB silage than for the Control. Phytol and lutein contents in the herbage did not change after ensiling. These results indicate that phytol and lutein in IR herbage can be preserved well in silage, irrespective of their fermentation condition.     

Effects of hybrid and bacterial inoculation on fermentation quality and fatty acid profile of barley silage

This study estimated the effects of hybrid and bacterial inoculant on fermentation quality and fatty acid profile of barley silages. Yuyeon (Silkless) and Youngyang (Silking) barley hybrids were harvested at 24.9 and 27.1% dry matter, respectively, and chopped to 10 cm lengths. Each hybrid was treated with or without an inoculant (2 × 10⁴ colony‐forming units/g of Lactobacillus plantarum). A total of 48 silos were prepared in an experiment with a 2 × 2 (hybrid × inoculant) treatment arrangement with four replications and three ensiling durations (2, 7 and 100 days). After 100 days of ensiling, Yuyeon silage had higher (P < 0.05) in vitro dry matter digestibility and C18:3n‐3 than Youngyang silage. Youngyang silage had higher (P < 0.05) acetic acid and C18:2n‐6 than Yuyeon silage. Inoculation reduced the C18:3n‐3 concentration of both hybrids and increased (P < 0.05) the C18:2n‐6 of Youngyang. However, fermentation quality was not improved by the inoculant. These results indicate that Yuyeon hybrid might have better potential benefits on animal performances due to its smooth awn and silkless nature, and higher in vitro dry matter digestibility. Its higher C18:3n‐3 would be better for improving fatty acid profile of meat or milk than Youngyang hybrid.     

Effect of ensiling and silage additives on fatty acid composition of ryegrass and corn experimental silages

Two experiments were conducted using laboratory mini-silos to study the effect of ensiling and silage additives on fatty acid (FA) composition, including minor or unusual FA, of ryegrass and corn silages. Ryegrass was ensiled for 12 wk with no additives, with the addition of a bacterial inoculant or formic acid. Corn was ensiled for 9 wk without additives, with the addition of a bacterial inoculant or calcium formate. Ensiling affected both total FA content and FA composition of ryegrass silages. Total FA concentration increased (P < 0.001) during ryegrass ensiling. The proportions (g/100 g of total FA) of the major unsaturated FA, 18:3n-3 and 18:2n-6, were not affected (P > 0.05) by ensiling. However, their concentration (mg/g of DM) in silages was greater (P=0.017 and P=0.001, respectively) than in fresh ryegrass. Two 18:2 FA (trans-11,cis-15 and cis-9,cis-15) that were not originally present in the fresh ryegrass were detected in silages. Silage additives affected the FA composition of ryegrass silages, mostly by increasing the proportions of SFA, but not on total FA concentration. Ensiling did not affect (P=0.83) total FA content of corn silages; however, FA composition was affected, mostly by decreasing the proportions of 18:2n-6 and 18:3n-3. Silage additives had no effect on corn silage FA composition. Exposing corn silages to air resulted in no oxidation of FA or reduction in total FA content or composition.     

Silage preparation and fermentation quality of kudzu,sugarcane top and their mixture treated with lactic acid bacteria,molasses and cellulase

We studied silage fermentation of kudzu (KZ), sugarcane top (ST) and their mixtures treated with additives to be able to effectively use available local feed resources. The silages were prepared using KZ, ST, KZ 90% + ST 10%, KZ 80% + ST 20%, KZ 70% + ST 30% and KZ 60% + ST 40%, based on fresh matter (FM). These silages were treated with 10⁸ colony‐forming units/g epiphytic lactic acid bacteria (LAB), 5% molasses and 0.02% cellulase of FM. The KZ contained higher crude protein (CP; 14.52%) content and lower levels of neutral detergent fiber (NDF; 62.15%) than those of ST (6.84% CP and 64.93% NDF) based on dry matter (DM). The KZ 60% + ST 40% silage fermented well with a higher (P < 0.05) lactic acid content and lower (P < 0.05) pH than those of the other mixed silages. Silages treated with molasses had lower (P < 0.05) ammonia‐N, NDF, acid detergent fiber, and hemi‐cellulose contents as well as pH, but higher (P < 0.05) DM, water‐soluble carbohydrate, and lactic acid contents, than those of the control, LAB and cellulase treatments. The results confirmed that KZ 60% + ST 40% was the best mixing ratio to prepare silage, and molasses improved silage fermentation and fiber degradation.     

Ensiling of total mixed ration containing persimmon peel: Evaluation of chemical composition and in vitro rumen fermentation profiles

The effects of inclusion of persimmon peel (PP) in total mixed ration (TMR) silage on its nutrient composition, tannin content, and in vitro ruminal fermentation were studied. Four types of TMR silages containing 0, 50, 100, and 150 g/kg of PP on a dry matter basis were prepared. The dietary contents of non‐fiber carbohydrate (NFC) decreased, while soluble protein fraction increased after ensiling of the TMR. In the TMR silages, the content of insoluble tannin increased (p < .05) with increasing PP level. The fraction of soluble protein decreased linearly (p < .01), while that of neutral detergent insoluble protein increased linearly (p < .01) with increasing the PP level in the TMR silages. The total gas and methane yields from the in vitro rumen fermentation of the TMR silages were lower (p < .01) than those of pre‐ensiled TMR and declined linearly (p < .01) with increasing PP level. These results indicate that adding PP to TMR silage may resist the breakdown of dietary protein during the ensiling process, although the ruminal fermentability of TMR possibly decreased after ensiling due to the loss of NFC.     

Silage quality as influenced by concentration and type of tannins present in the material ensiled: A meta‐analysis

Protein degradation during ensiling is a major problem. Tannins are known to prevent or decelerate protein degradation in the rumen and may be able to do so in silages as well. Therefore, the present evaluation aimed to analyse the influence of tannins on silage quality. This was done by integrating from all suitable experiments found in literature on the topic in a meta‐analysis approach. A total of 122 datasets originating from 28 experiments obtained from 16 published articles and one own unpublished experiment were included in the database. Tannins in the silages originated either from the plants ensiled or from supplementations of tanniferous plants or tannins extracted from such plants. Tannin concentrations ranged from 0 to 57.8 g/kg dry matter, and the ensiling period varied from 30 to 130 days. The analysis was based on the linear mixed model methodology in which the different studies were considered as random effects and tannin‐related properties (either concentration or type of tannins) were treated as fixed effects. Results revealed that greater concentrations of tannins were associated with a decrease of butyrate concentration in the silages (p < 0.05). An increasing tannin concentration was also accompanied with smaller proportions of soluble N, free amino acid N, non‐protein nitrogen and NH₃‐N in total silage N (p < 0.05). The relationships between hydrolysable and condensed tannins and the decline in butyrate and NH₃‐N concentrations in the silages were of different magnitude (p < 0.05). A higher tannin concentration was associated with a decline in in vitro dry matter digestibility. It was concluded that tannins apparently have the ability to limit extensive proteolysis which may occur during ensiling and thus may improve the fermentative quality of silages. A desired side effect seems to be given by the tannins' apparent property to limit the activity of the butyrate‐producing microbes.     

5株优良抑菌活性乳酸菌对全株玉米青贮品质的影响

为了探讨具有优良抑菌活性的乳酸菌对全株玉米青贮过程不同时期营养品质的影响,进一步验证并筛选出可提高玉米秸秆青贮品质的乳酸菌接种剂,将实验室前期从甘肃各地玉米秸秆青贮饲料中分离筛选获得的5株产酸快、多,且具有抑菌活性的优良乳酸菌分别添加到全株玉米秸秆中进行青贮,共设置6个试验组,分别在青贮第3、7、15、30天测定产物的干物质(DM)、粗蛋白(CP)、可溶性碳水化合物(WSC)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)和氨态氮(NH₃-N)含量及第30 天乳酸(LA)、乙酸(AA)、丙酸(PA)和丁酸(BA)含量。结果显示,发酵30 d后,5个处理组的DM、CP、ADF和LA含量显著高于对照组(P<0.05),NH₃-N和WSC含量显著低于对照组(P<0.05),B3-1组NDF显著高于对照组(P<0.05),但与其他处理组差异不显著(P>0.05),B3-1和B5-2组AA含量显著高于对照组(P<0.05),但与其他处理组差异不显著(P>0.05);各组DM、CP、WSC含量均随发酵时间延长而降低,而ADF、NDF和NH₃-N含量均随发酵时间的延长而升高;B3-1组在玉米秸秆全株青贮发酵各期的发酵品质和营养品质最优。以上结果表明5株乳酸菌均能显著改善青贮饲料发酵品质,其中植物乳杆菌B3-1的效果最好。     

Study on the bacterial community structure and fermentation characteristics of fresh and ensiled paper mulberry

Two experiments were conducted to investigate the bacterial community of fresh and ensiled paper mulberry prepared with or without lactic acid bacteria (LAB) inoculants in South China. In Experiment 1, the bacterial community, chemical composition, and fermentation products of paper mulberry were analyzed. The results showed that fresh paper mulberry had high crude protein content, buffering capacity value, and amounts of uncultured bacteria. Ensiled paper mulberry showed poor fermentation with high pH value, ammonia–N content, and butyric acid content. In addition, Enterobacter was the dominant genus in silage, followed by Lactobacillus and Enterococcus. Water-soluble carbohydrates, ammonia–N, propionic acid, pH, and lactic acid (LA) were the main factors affecting bacterial community of silage. In Experiment 2, the BP17 (Lactobacillus plantarum) from natural fermented paper mulberry silage and two commercial inoculants (Silage-help [SH] and Chikuso-1 [CH]) were used as additives. Compared with other treatments, BP17 inoculant decreased (p < 0.05) pH and ammonia–N content and increased (p < 0.05) LA content of silage. Inoculation of BP17 also increased the dominance of desirable Lactobacillus and inhibited the growth of harmful bacteria in silage. These results confirmed that paper mulberry could be ensiled and epiphytic LAB inoculant can improve its fermentation quality.     

Interactive effects of molasses by homofermentative and heterofermentative inoculants on fermentation quality,nitrogen fractionation,nutritive value and aerobic stability of wilted alfalfa (Medicago sativa L) silage

The effect of adding molasses (0, UM or 50 g/kg on DM basis, M) and two types of inoculant including homofermentative (HO) and a combination of homofermentative and propionate‐producing bacterial (HOPAB) inoculants on silage fermentation quality, nitrogen fractionation and aerobic stability of pre‐bloom, wilted alfalfa (AS) was determined in laboratory silos. The HOPAB inoculant was more effective than HO in reducing the alfalfa silage pH but increased propionate content in the absence of M (p < 0.05). Inoculation of HOPAB reduced (p < 0.01) acid detergent fibre (ADF) and increased (p < 0.01) lactate to acetate ratio compared with uninoculated AS. Acetate concentration was lower (p < 0.01) in HOPAB‐inoculated than other AS. This difference was more pronounced in M‐added AS (inoculants × M interaction, p = 0.01). Both inoculants reduced (p < 0.01) ammonia‐N content in AS added with M, whereas only HOPAB decreased (p < 0.01) ammonia‐N concentration in silage without M. Inoculants increased (p < 0.01) B₂ fraction in AS with M addition but had no effect on AS without M. Treating silages with HO‐UM increased (p < 0.05) C fraction (acid‐detergent insoluble‐N) but HOPAB decreased C fraction at two levels of M. Treating alfalfa crop with M and HOPAB improved aerobic stability by increasing the concentration of acetate and propionate of AS respectively. Adding M tended (p < 0.10) to increase short‐chain fatty acids (SCFA) and cumulative gas production (CGP). HOPAB alone increased DM disappearance at 24 h post‐incubation and effective degradability assuming outflow rate of 8%/h relative to untreated AS (p < 0.05). It was concluded that adding M had no pronounced effects on AS fermentation quality, but increased aerobic stability. HOPAB‐inoculated AS with no addition of M improved fermentation quality and increased DM degradability compared with HO.     

Effect of temperature and duration of ensiling on in vitro degradation of maize silages in rumen fluid

The effects of ensiling temperature and duration of ensiling on the feeding quality of whole‐crop maize (Zea mays L.) silages were investigated. Samples of one cultivar of maize plants were collected from two different fields, grown in different years on sandy soils. Samples were collected when the whole‐plant dry matter content was approximately 330 g/kg. Maize plants were chopped and ensiled in mini silos at three different ambient temperatures (5, 12 and 18 °C). The ensiling temperature affected the ensiling fermentation processes, causing different rates of pH decline and different final pH values. Samples from the silos were taken after 0 (not ensiled, i.e. control), 4, 8 and 16 weeks of ensiling. The silage samples were not dried, but ground‐frozen under liquid nitrogen to pass a 1‐mm sieve. The gas production technique was used to evaluate the influence of the ensiling temperature and the duration of ensiling on the degradation of the silage samples in rumen fluid. The gas production was highest when the maize was ensiled at 12 °C (p < 0.0001). An increase in ensiling duration caused a decrease in silage pH, accompanied by a decrease in gas production (p < 0.0001). The decrease in gas production was linearly related to the decrease in pH at the three temperatures. The present study shows that both ensiling temperature and ensiling duration play a significant role in the rumen degradability of maize silage.     

Nigella sativa (black cumin seed) as a biological detoxifier in diet contaminated with aflatoxin B1

Aflatoxin B₁ (AFB₁) is a common feed contaminant that adversely affects bird performance and product quality. A total of 600 7‐day‐old quail chicks were randomly allotted to eight experimental groups in a completely randomized design with five replicate pens and 15 quails per pen. Experimental treatments including two levels of AFB₁ (0 and 2.5 mg/kg) and 4 levels of Nigella sativa (NS) (0, 0.5, 1.0 and 1.5% of diet) were offered from 7 to 35 days of age to quail chicks. Although feeding of AFB₁ impaired gain (G) and feed conversion ratio, dietary NS increased G (p < 0.05). Relative weight of bursa of Fabricius increased with incremental levels of NS (p < 0.05). AFB₁ decreased the size of heart, but incremental levels of NS increased the relative weight of heart (p < 0.05). The liver hypertrophy was observed in birds receiving AFB₁ (p < 0.05). The birds in AFB₁ group had smaller testes than other groups (p < 0.05). Hematocrit value in birds fed AFB₁ was lower than that in other groups (p < 0.05) and incremental levels of NS increased blood hematocrit (p < 0.05). Amount of malondialdehyde (MDA) in meat samples of the birds fed AFB₁ was higher than those did not receive toxin but incremental levels of NS decreased the MDA concentration in affected birds (p < 0.05). AFB₁ suppressed the humoral immunity of the birds while NS augmented the antibody titres against sheep red blood cell and Newcastle disease virus antigens (p < 0.05). AFB₁ decreased lactic acid bacteria (LAB) and spore‐forming bacteria (SFB) but increased Escherichia coli (E. coli; p < 0.05). However, NS increased LAB and SFB but decreased the E. coli populations (p < 0.05). This study revealed that NS as a biological detoxifier could relatively attenuate the negative effects of AFB₁ in quails.     

Maternal dietary linoleic acid supplementation promotes muscle fibre type transformation in suckling piglets

As meat quality is basically dependent on muscle fibre characteristics, it is important to know how muscle fibres are regulated and transformed. This study aimed to investigate the effect of maternal dietary supplementation on muscle fibre types using 3% saturated fatty acid (palmitic acid, PA) or 3% unsaturated fatty acid (linoleic acid, LA) from 80 days of gestation to the weaning of offspring (25 days post‐natal). The results indicated that higher mRNA levels of MyHCI type genes were found in the soleus muscles of piglets that suckled from LA‐supplemented sows than from PA‐supplemented sows. In addition, LA treatment increased the gene expression of the type I muscle fibre marker troponin I (p < 0.01), suggesting that LA promoted muscle fibre type transformation to type I fibres. Moreover, PGC‐1α (p < 0.01) and MEF2c (p < 0.05) mRNA levels were higher in the piglets from the LA treatment group than in those from the PA treatment group. Furthermore, LA supplementation also significantly increased AMP‐activated protein kinase (AMPK) mRNA levels (p < 0.05), which is an upstream regulator of PGC‐1α. Collectively, these findings demonstrated that maternal dietary LA supplementation promoted muscle fibre transformation to type I fibre and that this process may be mediated through an AMPK‐dependent pathway.     

添加糖蜜对青稞秸秆和多年生黑麦草混合青贮发酵品质及营养价值的影响

试验在青稞秸秆与多年生黑麦草以6∶4混合的基础上,添加3%,4%和5%的糖蜜,旨在进一步改善混合青贮发酵品质和营养价值,为西藏地区青稞秸秆青贮利用提供理论依据。结果显示,青贮前14天,糖蜜添加组乳酸含量快速增加,pH值迅速下降。对照组pH值未能降至4.2以下,而糖蜜添加组均在4.0左右,乳酸、水溶性碳水化合物含量和乳酸/乙酸显著高于(P<0.05)对照组,氨态氮/总氮均低于对照组,且添加3%糖蜜已达到优质青贮饲料标准。青贮第60天糖蜜添加组有较高的粗蛋白含量,较低的中性洗涤纤维和酸性洗涤纤维含量,各组体外降解率均高于青贮材料。综合考虑,在青稞秸秆和黑麦草以6∶4混合的基础上添加3%的糖蜜可获得优质青贮饲料。     

Effects of supplementary mother liquor,by‐product of monosodium glutamate,on in vitro ruminal fermentation characteristics

Mother liquor (ML) is monosodium glutamate by‐product and contains much crude protein (CP). The objective of this study was to investigate the effect of supplementation of two types of MLs having different chemical compositions on in vitro ruminal fermentation characteristics. ML1 had 74% organic matter (OM) and 70% CP and ML2 had 85% OM and 83% CP on a dry matter (DM) basis. The experiments were conducted using 0.5 gDM rolled barley or ryegrass straw as substrates. Urea and freeze‐dried MLs were added at three levels of nitrogen to be isonitrogenous. The ML1 treatment increased gas production compared with the ML2 treatment in barley substrate condition (p < 0.05). The supplementary ML2 increased gas production compared with the supplementary urea, and the digestibilities of DM and neutral detergent fiber expressed exclusive of residual ash (NDFom) were higher for the supplementary ML2 than for the supplementary ML1 in straw substrate condition (p < 0.05). In both the conditions, ammonia nitrogen concentrations of the ML1 and ML2 treatments were lower than that of the urea treatment (p < 0.05). The results indicated that the supplementary ML1 and ML2 activated in vitro ruminal fermentation particularly in concentrate and roughage substrate conditions respectively.