System and control method for rumen in-vitro fermentation

Abstract

The present invention describes a system and control method for rumen in-vitro fermentation, said system comprising: -a bionic rumen with a drive module for controlling its movement; -a bionic reticulum with an external extrusion mechanism for regulating its motion; -a connecting structure linking the bionic rumen and bionic reticulum; -a control method that coordinates the movements of the rumen and reticulum to regulate the fermentation process. The bionic rumen and bionic reticulum are interconnected, enabling simultaneous biomimetic digestion and fermentation. By employing soft robotic actuator, the system effectively simulates the kneading and relaxation of the rumen, closely replicating natural digestive mechanics and fermentation kinetics. A real-time monitoring system has been integrated, allowing for online measurement of key parameters such as gas production and composition, thereby enabling more precise analysis of degradation kinetics. This invention provides an advanced research tool platform for ruminant nutrition, enabling improved digestion modeling accuracy. It also delivers significant environmental and economic benefits, including reduced methane emissions and enhanced feed utilization, thereby promoting sustainable livestock production.

Description

System and Control Method For Rumen In-Vitro FermentationTechnical Field

[0001] The present invention relates to an in-vitro digestion system for gas production in rumen in-vitro fermentation. In particular, it concerns a rumen-reticulum in-vitro fermentation reactor and its control method. Moreover, the present invention also concerns a method for degradation testing.Background Art

[0002] Rumen in‑vitro digestion simulation is crucial for studying ruminant nutrition, metabolism, and fermentation processes. Traditional systems often employ static fermenters constructed of glass or stainless steel and rely on manually collected ruminal fluid and microbes. Such systems fail to replicate the dynamic physiological conditions of the rumen, including peristaltic movement, pH regulation, and reticulo‑rumen emptying. Although in vivo and in situ methods provide direct insights, they are labor‑intensive, require fistulated animals, and incur high costs, in addition to ethical concerns. These shortcomings limit the accurate evaluation of feed digestibility, nutrient release kinetics, and structural changes in the rumen environment.Technical Problem

[0003] The technical problem addressed by the present invention is the absence of an in‑vitro fermentation system that can accurately simulate the dynamic physiological functions of the ruminant digestive tract. Existing rigid reactors are unable to mimic the flexible, peristaltic movements of the rumen and reticulum, resulting in inaccurate feed degradation testing and insufficient analysis of fermentation kinetics. Furthermore, current systems do not effectively incorporate real‑time monitoring of gas production and composition, which is essential for precise degradation analysis.Technical Solution

[0004] The present invention provides a system and control method for in-vitro rumen fermentation, comprising a bionic rumen, a bionic reticulum, and a connecting structure. The bionic rumen incorporates a driving module to control its peristaltic movement, while the bionic reticulum features an external extrusion mechanism to regulate its motion. The connecting structure integrates the bionic rumen and reticulum, facilitating coordinated bionic digestion and fermentation, thereby enhancing simulation accuracy and operational efficiency.

[0005] The bionic rumen is a soft-bodied structure driven by a soft robotic actuator composed of multiple segmented arrayed air chambers. These air chambers form a cross-shaped configuration, consisting of one arrayed segment intersecting perpendicularly with another. Each segment includes an air inlet and multiple interconnected chambers, which are connected to an external air source to enable precise control of rumen movement through pneumatic actuation.

[0006] The bionic reticulum is also a soft-bodied structure, actuated by external compression mechanisms such as a crank-slider system, worm gear mechanism, cam-slider system, or their combinations. Additionally, clamping plates and forked finger structures facilitate upward compression of the reticulum, providing flexible support and enhancing the bionic replication of natural digestive mechanics.

[0007] The system further includes a bionic esophagus module, consisting of a soft esophageal tube and external rolling compression devices to simulate esophageal peristalsis. A liquid feeding system, comprising a material reservoir, a peristaltic pump, a storage tank, and valves, regulates the flow of artificial saliva and rumen fluid into the esophagus. A gas collection module, equipped with a condensing reflux tube, a gas flow meter, and a gas composition analyzer, enables real-time monitoring and analysis of fermentation products.

[0008] The control method of the system involves three operational states to simulate rumen-reticulum peristalsis: State 1 (upper rumen relaxed, lower rumen relaxed, reticulum compressed), State 2 (upper rumen compressed, lower rumen relaxed, reticulum relaxed), and State 3 (upper rumen relaxed, lower rumen compressed, reticulum relaxed). The fermentation process follows a fixed cycle transitioning between these states, with adjustable parameters such as peristaltic intensity, state duration, and total fermentation time.

[0009] By integrating soft robotic actuation and real-time monitoring, the system precisely replicates the kneading and relaxation dynamics of the rumen, closely simulating natural digestive mechanics and fermentation kinetics. This invention serves as an advanced research platform for ruminant nutrition and digestion studies, enhancing modeling accuracy and supporting sustainable livestock production.

[0010] The present invention also provides an experimental method for measuring the in-vitro digestibility and degradation of feed. The method comprises loading the feed material into at least one soft reactor with continuously stable peristaltic movement, performing anaerobic fermentation within the bionic rumen and bionic reticulum soft reactors, directing the produced biogas to at least one buffer gas bag, which functions as both a temporary gas reservoir and an auxiliary mechanism for resetting the soft reactor to enhance bionic digestive dynamics, transferring the biogas to at least one gas flow measurement device to monitor its flow rate, and continuously recording and analyzing the biogas flow rate and composition in real time. This method enables precise monitoring and optimization of the in-vitro fermentation process.Advantageous Effects

[0011] The present invention provides the following advantageous effects:

[0012] For the first time in the prior art, the present invention discloses an in‑vitro fermentation reactor that simultaneously bionics the digestion processes of a ruminant's rumen and reticulum, including their specific interconnection and actuation methods, thereby faithfully reproducing the actual digestive process.

[0013] The invention employs soft robotics capable of flexibly kneading and relaxing the rumen, which effectively simulates the natural fermentation process occurring in the rumen. Moreover, the soft robotic module is composed of a segmented array of pneumatic actuators, which can serve as standardized components and be affixed—either partially or entirely—to the bionic rumen structure using adhesive or other methods.

[0014] In one embodiment, the invention utilizes a combination of a "flexible rumen with soft robotics" and a "flexible reticulum with a crank‑slider driven module clamping plate." This combination not only accurately replicates the anatomical structure of a ruminant's stomach, achieving a hardness comparable to that of the natural rumen and reticulum, but also closely simulates the contraction and emptying processes of the natural stomach through soft robotic actuation and clamping.

[0015] The invention provides a complete and highly bionic rumen‑reticulum reactor system that enables parameterized control of the digestive process. It also allows for the precise collection of product parameters generated by the reactor, thereby facilitating the further optimization of the bionic process by adjusting control parameters—such as the direction, magnitude, and frequency of the applied force—based on actual conditions..Description of Drawings

[0016] In the following, the invention will be described in further detail with reference to the figures. The examples given are adapted to illustrate the invention. The figures show:

[0017] Fig. 1 A schematic illustration of the structure of the bionic rumen and reticulum in vitro fermentation reactor;

[0018] Fig. 2 A schematic illustration of the soft robotic structure in the in vitro fermentation reactor of the present invention;

[0019] Fig. 3 A schematic illustration of the reticulum driving module of the present invention;

[0020] Fig. 4 A schematic illustration of the control process of the rumen and reticulum in vitro fermentation reactor; and

[0021] Fig. 5 A schematic illustration of the driving and control steps of the rumen and reticulum in vitro fermentation reactor.Best Mode

[0022] As shown in Figure 1, the in-vitro fermentation reactor with a bionic rumen and reticulum comprises a bionic rumen (21) and a bionic reticulum (22), connected by a connecting structure. The bionic rumen (21) incorporates a driving module to control its peristaltic movement, while the bionic reticulum (22) features an external extrusion mechanism to regulate its motion. The connecting structure integrates the bionic rumen (21) and bionic reticulum (22), facilitating coordinated biomimetic digestion and fermentation, thereby enhancing simulation accuracy and operational efficiency.

[0023] In a specific embodiment, as shown in Figures 1 and 2, the bionic rumen and reticulum fermentation module comprises a bionic rumen (21) and a bionic reticulum (22), with the bionic rumen (21) being connected to the bionic reticulum (22) through a Reticulum-Rumen connection tube (27). The Reticulum-Rumen connection tube (27) is equipped with a pressure gauge (29), and the tube is fixed using a screw tubing clamp 2 (28). The pressure gauge (29) detects the internal pressure of the reactor, while the screw tubing clamp 2 (28) controls the flow within the tube.

[0024] The bionic rumen (21) is mounted on a fermentation scaffold (24). In a specific embodiment, the bionic rumen (21) is further equipped with a rumen constraint net (23) embedded in the rumen to restrict deformation and prevent excessive expansion. The rumen constraint net (23) is made of inelastic soft rope material.

[0025] An esophageal feeding connector (25) is provided to supply the material to be fermented to the rumen. In addition to its function for feeding the material, the connector (25) also serves as a switch to control the flow. The esophageal feeding connector (25) is equipped with a screw tubing clamp 1 (26), which not only regulates the flow rate of the material through the connector but also ensures the sealing of the soft reactor.

[0026] A gas collection tube (210) is provided to collect gases produced primarily by the bionic rumen (21) during digestion, with some contribution from the bionic reticulum (22).

[0027] In a specific embodiment, the bionic rumen (21) can be a soft bionic rumen, and the bionic reticulum (22) can be a soft bionic reticulum.

[0028] In a specific embodiment, the driving mechanism of the bionic rumen (21) is a drive module. This drive module is used to drive the movement of the bionic rumen (21). The bionic rumen (21) is connected to an external gas collection module for collecting gases generated by the bionic rumen (21). The bionic rumen (21) and the bionic reticulum (22) are interconnected, and the bionic rumen (21) is also connected to an external bionic esophagus module to supply the fermented material to the rumen.Mode for Invention

[0029] As shown in Figure 2, the soft robotic actuator used in the bionic rumen (21) and bionic reticulum (22) adopts a multi-segment array airbag structure. This multi-segment array airbag can have various shapes. Preferably, the soft robotic actuator's multi-segment array airbag consists of one segment of airbag and another segment of airbag arranged at a right angle to form a cross-shaped airbag. The cross-shaped section is connected to a pneumatic control system, and by controlling the operational state of the cross-shaped airbag, the contraction and expansion of the soft bionic rumen (21) are achieved, mimicking peristaltic movements. Based on existing experimental results, the cross-shaped airbag yields the best performance.

[0030] In a specific embodiment, the soft robotic actuator driving module includes an air port (11), the first gripper (12), the second gripper (13), the third gripper (14), and the fourth gripper (15). Each gripper consists of multiple individual interconnected airbags. The air port (11) is connected to an external air source to provide power. The four grippers are evenly distributed in a cross shape, with a bottom plate at the vicinity of the bionic rumen (21). The bottom plate includes a bottom layer (18), a intermediate layer (17), and an top layer (16) arranged sequentially. The bottom layer (18) and top layer (16) layers are made of soft materials such as silicone or hydrogel, and the intermediate layer (17) is embedded between the bottom and top layers and made of inelastic materials such as thermoplastic polyurethane (TPU) elastomer rubber or nylon mesh.

[0031] In the rumen section, the soft robotic actuator is fixed to the bionic rumen using common fixing methods, including but not limited to adhesives.

[0032] As shown in Figure 3, the external squeezing mechanism of the bionic reticulum (22) can be a common mechanical actuator, such as a crank-slider mechanism. Preferably, the squeezing action of the bionic reticulum (22) is driven by a crank-slider mechanism to simulate the squeezing effect from the bottom to the top.

[0033] In a specific embodiment, the crank-slider mechanism comprises a left eccentric wheel (31), a left crank shaft (32), a left connecting rod (33), a left bearing block (34), a left clamping plate (35), a left curved forked finger (36), a right curved forked finger (37), a right clamping plate (38), a right bearing block (39), a right connecting rod (310), a right crank shaft (311), and a right eccentric wheel (312). The motor provides the driving force, which is transmitted to the two crank-slider mechanisms via a gear mechanism. The two crank-slider mechanisms rotate in opposite directions, allowing them to simultaneously reach both the 0° and 180° dead points. At the 0° dead point, the distance between the clamping plates is maximized, whereas at the 180° dead point, the clamping plates are in their closest position. The two mirror-image clamping plates are arranged on either side of the soft reticulum chamber, and their periodic movement facilitates the peristaltic motion of the reticulum section.

[0034] Additionally, clamping plates and forked finger structures facilitate upward compression of the bionic reticulum (22), providing flexible support and enhancing the biomimetic replication of natural digestive mechanics.

[0035] It should be noted that although the crank-slider mechanism is used in this embodiment, any common mechanical actuator capable of providing controllable, periodic squeezing action to the bionic reticulum (22) is acceptable for realizing the functions of the devices in this invention.

[0036] By utilizing such or similar actuators, the actuation of the bionic rumen (21) and bionic reticulum (22) replicates the gentle peristaltic motion of a natural rumen and reticulum, promoting mass transfer of the fermenting material and improving its contact with microorganisms. This biomimetic approach ensures a more microorganism-friendly environment and achieves superior performance compared to conventional stirring.

[0037] As illustrated in Figure 4, the fermentation process progresses through multiple states: initially transitioning from state 1 to state 2, followed by state 3, then reverting to state 2 before transitioning again to state 3, and subsequently entering a prolonged interval before returning to state 1. The specific characteristics of states 1 to 3 are detailed in Table 1.

[0038] During the peristaltic motion of the bionic rumen (21) and bionic reticulum (22), three distinct driving states are employed. The switching between these states replicates the natural peristaltic motion of the ruminant stomach. The actuation of the bionic rumen (21) is regulated by adjusting the internal pressure of the soft robotic actuator, thereby simulating the contraction and relaxation cycles of a natural rumen.

[0039] The compression mechanism of the bionic reticulum (22) simulates the contraction of the natural reticulum through external actuation. The clamping plates exert controlled external force in two sequential compression phases: initially, the gap between the clamping plates is reduced by N1% (60%–70%), followed by an increase of N2% (10%–20%), and a subsequent reduction of N3% (90%–95%). The parameters N1%, N2%, and N3% are preset values that can be adjusted to precisely regulate the peristaltic motion of the bionic reticulum (22).

[0040] Table 1: Fermentation Process Rumen and Reticulum Peristaltic States

[0041] ComponentState 1State 2State 3Rumen(Upper)Expanded(○)Compressed(●)Expanded(○)Rumen (Lower)Expanded(○)Expanded(○)Compressed(●)ReticulumCompressed(●)Expanded(○)Expanded(○)

[0042] Legend: ● = Compressed, ○= Expanded

[0043] The entire fermentation process involves the switching of three states. The number of cycles, the time intervals, and the durations of each state depend on the actual conditions of the animal, with longer intervals between certain states.

[0044] During fermentation, the following parameters can be adjusted: (1) The peristaltic intensity, which regulates the minimum gap of the crank-slider mechanism during compression and the pressure applied by the soft grippers to simulate natural contractions; (2) The time intervals between transitions of the three peristaltic states; (3) The duration of each individual fermentation cycle; and (4) The total fermentation time.

[0045] As illustrated in Figure 5, the present invention discloses a bionic rumen and bionic reticulum reactor, designed using advanced technological methods to highly replicate the anatomical structure and physiological functions of the natural rumen and reticulum. The bionic rumen (21) utilizes soft robotics technology to simulate the motion of the upper and lower parts of the rumen, while the bionic reticulum (22) is actuated by a crank-slider mechanism to simulate its contraction motion. By controlling the state transitions of the actuators, the reactor can switch between three preset states. The timing and duration of these state transitions are adjustable, enabling the achievement of various bionic digestive effects. This reactor is designed to accurately replicate the digestion process of ruminants, offering significant applications in feed fermentation and degradation studies.

[0046] The technical features disclosed in the embodiments above may be freely combined unless technically incompatible. While not all possible combinations are explicitly described, any combination falling within the scope of the invention is deemed to be covered by this disclosure.

[0047] The embodiments described above illustrate possible implementations of the invention and should not be construed as limiting its scope. A person skilled in the art may introduce modifications or improvements without departing from the core inventive concept. Such variations are considered part of the invention, and the scope of protection is defined solely by the appended claims.Industrial Applicability

[0048] The invention is applicable to the field of ruminant nutrition research, feed evaluation, and optimization of fermentation processes. It provides a cost‑effective and ethically acceptable alternative to in vivo and in situ methodologies, facilitating detailed studies on feed digestibility, nutrient release kinetics, and fermentation dynamics. Additionally, the system is particularly useful for screening feed formulations and additives, as well as for developing strategies aimed at reducing methane emissions, thus supporting sustainable livestock production.Free Text of Sequence listing

[0049] 11.   Air port

[0050] 12.   The first gripper (Gripper 1)

[0051] 13.   The second gripper (Gripper 2)

[0052] 14.   The third gripper (Gripper 3)

[0053] 15.   The fourth gripper (Gripper 4)

[0054] 16.   Top layer

[0055] 17.   Intermediate layer

[0056] 18.   Bottom layer

[0057] 21.   Bionic rumen

[0058] 22.   Bionic reticulum

[0059] 23.   Rumen Constraint Net

[0060] 24.  Fermentation Scaffold

[0061] 25.   Esophageal Feeding Connector

[0062] 26.   Screw Tubing Clamp 1

[0063] 27.  Reticulum-Rumen Connection Tube

[0064] 28.   Screw Tubing Clamp 2

[0065] 29.   Pressure Gauge

[0066] 210.  Gas collection tube

[0067] 211.  Tube bracket

[0068] 31.   Left eccentric wheel

[0069] 32.   Left crank shaft

[0070] 33.   Left connecting rod

[0071] 34.   Left bearing block

[0072] 35.   Left clamping plate

[0073] 36.   Left curved forked finger

[0074] 37.   Right curved forked finger

[0075] 38.   Right clamping plate

[0076] 39.   Right bearing block

[0077] 310.  Right connecting rod

[0078] 311.  Right crank shaft

[0079] 312.  Right eccentric wheel.

Claims

1. A rumen-reticulum in-vitro fermentation system, comprising: - a bionic rumen (21) including a drive module for controlling its movement; - a bionic reticulum (22) including an external extrusion mechanism for regulating its motion; - a connecting structure linking the bionic rumen (21) and the bionic reticulum (22); wherein the drive module controls the peristaltic motion of the bionic rumen (21), and the external extrusion mechanism facilitates the mechanical compression of the bionic reticulum (22) to simulate natural digestion dynamics.2.The system of claim 1, wherein the bionic rumen (21) is a soft-bodied structure chamber incorporating a soft robotic drive module mounted on its surface to enable biomimetic motion.3.The system of claim 2, wherein the soft robotic drive module comprises a segmented array of pneumatic actuators, including an air port (11) and a cross shaped actuator formed by:- the first gripper (Gripper 1) (12);- the second gripper (Gripper 2) (13);- the third gripper (Gripper 3) (14); and- the fourth gripper (Gripper 4) (15);and further including a top layer (16), an intermediate layer (17), and a bottom layer (18).4.The system of claim 1, wherein the bionic reticulum (22) is configured as a soft structured chamber, and the external extrusion mechanism comprises a crank-slider mechanism.5.The system of claim 4, wherein the crank-slider mechanism comprises:- a left eccentric wheel (31), a left crank shaft (32), a left connecting rod (33), a left bearing block (34), a left clamping plate (35), and a left curved forked finger (36); and- a right curved forked finger (37), a right clamping plate (38), a right bearing block (39), a right connecting rod (310), a right crank shaft (311), and a right eccentric wheel (312).Preferably, the squeezing effect of the reticulum is driven by the crank-slider mechanism to simulate the contraction movement from the bottom to the top.6.The system of claim 1 further comprising a connecting structure that includes an esophageal feeding connector (25) secured by a screw tubing clamp 1(26) and a Reticulum-Rumen connection tube (27) secured by a screw tubing clamp 2(28), wherein the esophageal feeding connector (25) and the Reticulum-Rumen connection tube (27) are arranged to couple the bionic rumen (21) and the bionic reticulum (22).7.The system of claim 1, further comprising a pressure gauge (29) and a gas collection system connection tube (210), wherein the gas collection tube (210) is supported by a tube bracket (211).

8. A control method for the system of any one of claims 1–7, comprising:- operating the bionic rumen (21) and bionic reticulum (22) through three cyclic movement states, wherein:State 1: an upper section of the biomimetic rumen expands while a lower section expands, and the biomimetic reticulum compresses;State 2: the upper section of the biomimetic rumen contracts while the lower section expands, and the biomimetic reticulum expands; andState 3: the upper section of the biomimetic rumen expands while the lower section contracts, and the biomimetic reticulum expands;initiating the process with State 1;entering a cyclic phase wherein State 2 transitions to State 3 and then reverts to State 2, followed by an additional transition to State 3, and then pausing for an extended interval;repeating the cyclic phase n times; andreturning to State 1 upon completion of the cyclic phase.9.The control method of claim 8, further comprising setting fermentation control parameters including:- adjustment of the peristaltic intensity by controlling a maximum compression gap of the crank-slider mechanism and the applied pressure of the soft drive module grippers;- the duration of each movement state;- the time interval for state transitions;- the fermentation cycle duration; and- the total fermentation period.

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