Effects of Piromyces sp. CN6 CGMCC 14449 on fermentation quality, nutrient composition and the in vitro degradation rate of whole crop maize silage

Abstract

This study investigated the effects of the rumen fungus Piromyces sp. CN6 CGMCC 14449 as a silage additive on the fermentation quality, nutrient composition and in vitro digestibility of whole crop maize silage. Whole crop maize served as the silage material and was vacuum packed in polyethylene bags. Three ensiling treatments were applied: a control (CK), addition of a fungus (FU) at 10 5 thallus-forming units per gram, and addition of compound enzyme (EN) at 0.033 mg/g (containing cellulase and xylanase at activities of 90 filter paper units and 6000 IU per gram, respectively). Compared with the CK, the FU and EN treatments decreased the pH after 30 days fermentation ( P <0.05). Both FU and EN treatments increased the lactate, crude protein, and water-soluble carbohydrate contents ( P <0.05), whereas reduced the acetate, ADF and NDF contents as well as the ammonia nitrogen to total nitrogen ratio in silage after 30 days of ensilaging ( P <0.05), compared with those for the CK, while no changes were found in the dry matter and dry matter recovery ( P > 0.05). The fungal inoculant increased the in vitro digestibility of dry matter, NDF and ADF in silage after 30 days fermentation ( P <0.05). In conclusion, the rumen fungus Piromyces sp. CN6 CGMCC 14449 can improve the quality and nutrient composition of whole crop maize silage and increase the crude fibre digestibility.

The Present Role and New Potentials of Anaerobic Fungi in Ruminant Nutrition

“…Consequently, plant biomass like straw that is yet widely unexploited in ruminant nutrition could get upvalued and therefore become a more extensively used diet component in ruminant livestock production systems. Such a mode of action was already indicated by two pilot studies investigating the impact of AF inoculation on quality and ruminal degradation of rice straw or whole crop maize silage [ 81 , 82 ]. The plant materials were ensiled with AF strains isolated from herbivore guts, which in both approaches led to an increased ruminal dry matter and fiber degradability during subsequent incubations either in vitro [ 82 ] or in situ [ 81 ].…”

“…Although these data provide first evidence of the AF potential as silage additives, it has to be noted that the two studies [ 81 , 82 ] on AF-treated silages were conducted at minor lab-scale. Immense quantities of AF cultures would be necessary to inoculate the large volumes of forage material sufficiently, which are moreover ensiled in very few days on cattle farms.…”

“…The plant materials were ensiled with AF strains isolated from herbivore guts, which in both approaches led to an increased ruminal dry matter and fiber degradability during subsequent incubations either in vitro [ 82 ] or in situ [ 81 ]. Remarkably, compared to the control silages, whole crop maize silages treated with AF also showed an improved silage quality, i.e., higher lactic acid concentrations along with a lower pH and less acetic acid [ 82 ], which was also apparent for pH in AF-treated rice straw silages [ 81 ].…”

“…Consequently, it appears that the enzymatic array of AF can be deployed as silage additives. Indeed, AF-derived enzymes possess several advantageous properties, predestinating them for this purpose: fungal CAZymes are widely expressed extracellularly [ 24 , 83 ] and highly effective in degrading cell wall structures over a wide pH range (pH 4–8) [ 82 ], which is further emphasized by the target affinity of AF CAZymes for recalcitrant fiber components [ 23 ], i.e., those that are insufficiently degraded in the forestomach system [ 84 ]. The latter AF feature is of particular relevance because less robust fiber structures, such as hemicelluloses, are also degraded by lactic acid-induced acidolysis in the silo [ 85 ] or else can later be fermented efficiently by rumen microorganisms [ 84 ].…”

Effects of Urtica cannabina to Leymus chinensis Ratios on Ruminal Microorganisms and Fiber Degradation In Vitro

“…The degree of nutrient metabolism in the substrate can reflect the rumen microbial activity, as well as the fermentation degree of the substrate [26]. Jin et al [13] demonstrated that U. cannabina can be used as the replacement for the traditional feed mixture of forage in the feeding experiments.…”