Effects of Urea Supplementation On The Nutritional Quality And Microbial Community of Alfalfa (Medicago Sativa L.) Silage

The objectives of this study were to evaluate the contribution of urea on the nutritional quality and microbial community of ensiled alfalfa (Medicago sativa L.). Alfalfa silage was control group without urea (AL), supplementation with 0.5 % urea (AU1), or supplementation with 1 % urea (AU2). The silage tanks were opened and sampled after silage at 0, 15, 30, and 60 d. Results showed that AU2 had higher pH, ratio of NH3-N/TN and CP content than those in AL and AU1 while AU1 had higher ADF than that in AL and AU2 after 15 d silage. Richness and diversity indices of microbial communities in silage were no significant differences among AL, AU1 and AU2 group. Proteobacteria (58.23%) and Firmicutes (40.95%) were the predominant phylum in three groups during the silage process. The percent of community abundances on genera level of Enterobacteriaceae (37.61%) and Klebsiella (41.78%) in AL were a little higher than those in AU1 (30.39%, 25.02%) and AU2 (33.48%, 26.92%). These results showed that silage with urea alone could not improve the quality of alfalfa.

Top-Down Enrichment Strategy to Co-cultivate Lactic Acid and Lignocellulolytic Bacteria From the Megathyrsus maximus Phyllosphere

Traditionally, starting inoculants have been applied to improve ensiling of forage used for livestock feed. Here, we aimed to build up a bioinoculant composed of lactic acid-producing and lignocellulolytic bacteria (LB) derived from the Megathyrsus maximus (guinea grass) phyllosphere. For this, the dilution-to-stimulation approach was used, including a sequential modification of the starting culture medium [Man, Rogosa, and Sharpe (MRS) broth] by addition of plant biomass (PB) and elimination of labile carbon sources. Along 10 growth-dilution steps (T1–T10), slight differences were observed in terms of bacterial diversity and composition. After the sixth subculture, the consortium started to degrade PB, decreasing its growth rate. The co-existence of Enterobacteriales (fast growers and highly abundance), Actinomycetales, Bacillales, and Lactobacillales species was observed at the end of the selection process. However, a significant structural change was noticed when the mixed consortium was cultivated in higher volume (500ml) for 8days, mainly increasing the proportion of Paenibacillaceae populations. Interestingly, Actinomycetales, Bacillales, and Lactobacillales respond positively to a pH decrease (4–5), suggesting a relevant role within a further silage process. Moreover, gene-centric metagenomic analysis showed an increase of (hemi)cellulose-degrading enzymes (HDEs) during the enrichment strategy. Reconstruction of metagenome-assembled genomes (MAGs) revealed that Paenibacillus, Cellulosimicrobium, and Sphingomonas appear as key (hemi)cellulolytic members (harboring endo-glucanases/xylanases, arabinofuranosidases, and esterases), whereas Enterococcus and Cellulosimicrobium have the potential to degrade oligosaccharides, metabolize xylose and might produce lactic acid through the phosphoketolase (PK) pathway. Based on this evidence, we conclude that our innovative top-down strategy enriched a unique bacterial consortium that could be useful in biotechnological applications, including the development/design of a synthetic bioinoculant to improve silage processes.

The Dairy Cow Slurry Composition Used as Organic Fertilizer Is Influenced by the Level and Origin of the Dietary Protein

Less than 30% of dairy cattle’s nitrogen ingested is retained in milk. Therefore, large amounts of nitrogen can be excreted in manure and urine with a potential environmental impact. In addition, some legume forages can be more susceptible to proteolysis during the silage process than grasses, and dairy cows fed these legume silages would excrete a larger quantity of nitrogen in slurry. The objectives of this work were to evaluate the amount of nitrogen excretion in dairy cows fed different protein levels and legume silages with a view to improve the slurry quality as a co-product that can be used as fertilizer. Two double 3 × 3 Latin square trials were carried out in order to study three different protein levels (high, medium, and low) and three different silages (grass, faba bean, and field pea). Dry matter intake, milk production, and composition were not affected by treatments. The excretion of ammonia-N in the urine was almost four times lower in the diet with the lowest protein level. The ammonia-N in the urine was twice as high with the pea silage than faba bean and grass silages. In conclusion, the diet containing 13% of protein meets the protein requirement for lactating cows producing 31 kg daily, with low nitrogen excretion in the urine, and the main pathway for the excretion of surplus nitrogen from legume silages is through urine and the metabolization of pea silage protein goes toward ammonia-N.

Multi-Mycotoxin Contamination of Maize Silages in Flanders, Belgium: Monitoring Mycotoxin Levels from Seed to Feed

Maize silage, which in Europe is the main feed for dairy cattle in winter, can be contaminated by mycotoxins. Mycotoxigenic Fusarium spp. originating from field infections may survive in badly sealed silages or re-infect at the cutting edge during feed-out. In this way, mycotoxins produced in the field may persist during the silage process. In addition, typical silage fungi such as Penicillium spp. and Aspergillus spp. survive in silage conditions and produce mycotoxins. In this research, 56 maize silages in Flanders were sampled over the course of three years (2016–2018). The concentration of 22 different mycotoxins was investigated using a multi-mycotoxin liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, and the presence of DNA of three Fusarium spp. (F. graminearum, F. culmorum and F. verticillioides) was analyzed in a selection of these samples using quantitative polymerase chain reaction (qPCR). Every maize silage contained at least two different mycotoxins. Nivalenol (NIV) and deoxynivalenol (DON) were the most prevalent (both in 97.7% of maize silages), followed by ENN B (88.7%). Concentrations often exceeded the EU recommendations for DON and zearalenone (ZEN), especially in 2017 (21.3% and 27.7% of the maize silages, respectively). No correlations were found between fungal DNA and mycotoxin concentrations. Furthermore, by ensiling maize with a known mycotoxin load in a net bag, the mycotoxin contamination could be monitored from seed to feed. Analysis of these net bag samples revealed that the average concentration of all detected mycotoxins decreased after fermentation. We hypothesize that mycotoxins are eluted, degraded, or adsorbed during fermentation, but certain badly preserved silages are prone to additional mycotoxin production during the stable phase due to oxygen ingression, leading to extremely high toxin levels.

PSII-13 Effect of corn stover silages inoculated with effective microorganisms (EM®) on digestibility of sheeps

The objective of the study was to evaluate the effect of corn stover silages with two sources of energy (cane molasses or milk whey) and EM (effective microorganisms, 1 mL/kg DM) on the digestibility of nutrients and rumen fermentation. We hypothesized that inoculation with EM (lactobacillus spp and Rhodopseudomona palustris and Saccharomyces cerevisiae) in the silage process of corn stover coud improve the in vivo digestibility and ruminal fermentation in sheep. Six male sheep with cannula in the rumen were used in a 6 x 6 Latin square design. Experimental periods consisted of 11 d for diet adjustment followed by 5 d for collection. The animals were housed in metabolic cages, with a harness to collect faeces individually. Diets consisted of concentrate (corn grain, soybean meal, mineral salt) 55% and corn stover 45% dry basis. The treatments were: CS-AMW= Corn stover with acid milk whey, CS-CM= corn stover with sugar cane molasses, SIL-AMW= corn stover silage with acid milk whey, SIL-CM= corn stover silage with cane molasses, SIL-AMW-EM= corn stover silage with acid milk whey and EMand SIL-CM-EM= Corn stover silage with cane molasses and EM. The results were analyzed with PROC MIXED procedures of SAS. The inoculation of corn stover with EM increased (P < 0.05) the content of CP in SIL-AMW-EM and SIL-CM-EM respect CS-CM (Table 1). SIL-CM-EM increase (P < 0.05) the ruminal N-NH3 and pH (Table 2) but no effect was observed for digestibility (Table 3). However, the SIL-AMW improved (5.8%, P < 0.05) the OM digestion compared with CS-AMW. A diet with 45% corn stover silage with EM was not sufficient to improve in vivo digestibility of nutrients in sheep. This project was supported by UNAM,DGAPA, PAPIIT (IT202120)

The Bacterial Community Associated with the Amarillo Zamorano Maize (Zea mays) Landrace Silage Process

Maize silage is used in the diet of dairy cows, with suitable results in milk yield. In this study, the composition and diversity of the bacterial communities of the silage process of Amarillo Zamorano (AZ) Mexican maize landrace with relation to the Antilope (A) commercial hybrid are described. From both types of maize, seeds were sown in experimental plots, plants harvested at the reproductive stage, chopped, and packed in laboratory micro-silos. Physicochemical parameters were evaluated, and DNA was extracted from the juice in the micro-silos. The bacterial communities were analyzed by next-generation sequencing (NGS) of seven hypervariable regions of the 16S rRNA gene. The composition of both bacterial communities was dominated by Lactobacillales and Enterobacteriales, Lactobacillales mainly in A silage and Enterobacteriales in AZ silage; as well, the core bacterial community of both silages comprises 212 operational taxonomic units (OTUs). Sugar concentration showed the highest number of significant associations with OTUs of different phyla. The structure of the bacterial communities was different in both silage fermentation processes, showing that AZ silage has a shorter fermentation process than A silage. In addition, NGS demonstrated the effect of the type of maize and local conditions on silage fermentation and contributed to potential strategies to improve the quality of AZ silage.

Qualitative monitoring of corn silage stored in commercial bunker silos and used as feed for dairy cattle in the western region of Santa Catarina State, Brazil

Corn ensiling is a feed preservation practice used for ruminant production. During the process of making and opening the silos, the quality of the silage may change due to the entrance of air, which can cause damage and decrease the voluntary intake of the animals. The objective of this work was to evaluate the chemical composition of corn silages during their use in commercial bunker silos, as well as to correlate this with qualitative and quantitative characteristics related to the silage making process. Technical data on silage making and samples were collected from 14 bunker silos, with five samples collected along each silo (at 10, 30, 50, 70 and 90% of their lengths); additionally, two sampling methodologies were compared (“W” vs. layer collections in silo panels: top, middle and bottom). The values for the pH and titratable acidity (TA) were significant (p < 0.05) in relation to the sampling method, where the pH of the top was higher (3.8±0.5) than that of the middle and the bottom layers (3.6±0.3 and 3.5±0.3); therefore, the TA was lower in the top of the silos. The dry matter, ashes, crude protein, neutral detergent fiber, acid detergent fiber, pH, TA, as well as the silo sampling method during the unloading of commercial bunker silos did not differ for any of the variables (p < 0.05). Also, the particle size did not differ during the unloading of the commercial bunker silos (p > 0.05). According to the collected technical data, 78.57% of the bunker silos were built directly on the ground, the harvesting equipment was mostly borrowed from municipalities or farmers’ associations (for 35.7 and 28.5% of the farms, respectively), and in only 64.2% of the farms, the harvester was sharpened before silage cutting. Good practices were applied during the corn silage process and throughout the use of the silos, homogeneous quality was detected in the western region of Santa Catarina. Either “W” or layer collections can be used to sample corn silage.

Bioactive forage legumes as a strategy to improve silage quality and minimise nitrogenous losses

The use of forage legumes as a source of protein for ruminants is a sustainable strategy to reduce the use of inorganic-nitrogen fertiliser. In addition, some legumes species contain naturally bioactive secondary compounds, which could improve silage quality and digestive processes in ruminants. The aim of this study is to investigate the effects of bioactive legumes containing condensed tannins or polyphenol oxidase, ensiled alone or in mixture with a grass, on silage quality and conservation characteristics. Six mini-silos were prepared in triplicate as follows: 100% red clover (RC), 100% sainfoin (SF), 100% Timothy (T, control without bioactive compounds), binary mixtures 50% T + 50% RC, 50% T + 50% SF and ternary mixture 50% T + 25% RC + 25% SF. Condensed tannins remain unaltered during the silage-making process in terms of quantity and chemical structures, while polyphenol oxidase is activated during this process. All the silages that contained bioactive legumes were better conserved than the pure grass silo. In addition bioactive legumes were able to preserve protein from their degradation during the silage process. Inclusion of bioactive legumes can improve silage quality, and polyphenol oxidase may be more efficient than condensed tannins to improve the nitrogen value of silage.

Dietary utilisation of protein and energy from fresh and ensiled coffee pulp by the Nile tilapia, Oreochromis niloticus

Dietary protein and energy utilisation of diets containing fresh and ensiled coffee pulp were studied on 3.2 ± 0.2 g Nile tilapia for 28 days. Diets formulation and feeding were designed on the basis of daily dietary protein and energy allowance. A control diet A (100 % protein and 100 % energy allowance) corresponding to 15 g CP kg-1 day-1 and 750 kJ kg-1 day-1, a low protein control diet B (80 % protein and 100 % energy allowance), two diets C and E (100 % protein and 100 % energy allowance) where 20 % of protein were supplied by coffee pulp, and two diets D and F with the same amount of coffee pulp than in C and E and supplementation in non-protein energy. Inclusion of coffee pulp in the diet strongly impaired growth and feed utilisation. Silage process improved overall feed utilisation comparing to fresh coffee pulp. Results showed that fresh or ensiled coffee pulp was not a suitable feedstuff for Nile tilapia. However, better knowledge on modification occurring during silage process could allow finding the way to significantly improve nutritive value of coffee pulp by-products.