A screening device and comprehensive evaluation method suitable for narrow-clawed crayfish bait

Abstract

The application discloses a kind of screening device and comprehensive evaluation method suitable for narrow-chela crayfish bait, characterized by including sinking food table, half section baffle, long arm, light shield, support, central temporary breeding area and test channel, the light shield is suspended in the just above of central temporary breeding area by support;Multiple test channels surrounded by long arm are radially distributed in the periphery of central temporary breeding area, one end is connected with central temporary breeding area and the other end is closed, multiple half section baffles are staggered in test channel, sinking food table is set in the closed end of test channel, its comprehensive evaluation method combines short-time behavior observation to extract first feeding latency and first selection rate, combines long-acting feeding to measure real food intake in sinking food table, and comprehensive evaluation model is calculated by substituting comprehensive baiting index, the greater the comprehensive baiting index represents the higher the comprehensive baiting potency of the group of baiting agent;The advantage is to realize the precise screening of multiple baiting agents with low stress, high throughput and multidimension.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, and in particular relates to a screening device and comprehensive evaluation method for attractants suitable for crayfish. Background Technology

[0002] In aquaculture, attractants can effectively improve feed intake, promote growth, and reduce feed waste in aquatic animals. Therefore, efficiently and accurately screening formulations with good attractant effects is of great significance to the aquaculture industry. Currently, the screening of attractants for aquatic animals mainly uses behavioral devices, such as Y-mazes and cross mazes, combined with tactic selection as an evaluation indicator. However, existing technologies have the following obvious drawbacks: First, traditional screening devices have a limited number of test channels (usually 2-4), making it difficult to simultaneously meet the needs of high-throughput parallel screening of multiple attractants, resulting in low testing efficiency. Second, existing devices often neglect the unique biological learning characteristics of specific aquatic animals (especially benthic crustaceans, such as crayfish). Crayfish exhibit significant dark-light attraction (preferring shade), while existing devices are usually exposed to light, easily causing environmental stress in the tested individuals, manifesting as disordered running and abnormal activity, thus seriously interfering with their response behavior to the actual odor of the attractant and affecting the accuracy of the test results. Third, current evaluation methods are too simplistic. Most methods rely solely on short-term behavioral observations (such as tactic selection rates) and lack precise measurement of long-term, absolute feed intake. This "tactic-focused, feed-neglecting" evaluation model cannot comprehensively distinguish between the "odor attractiveness" and "actual palatability" of attractants, easily producing false positive results such as "shrimp are attracted to the feeding platform but ultimately do not feed," leading to poor performance of the selected attractant formulations in actual aquaculture applications. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a screening device and comprehensive evaluation method for attractants suitable for crayfish, which enables low-stress, high-throughput, and multi-dimensional precise screening of various attractants.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a screening device for attractants suitable for crayfish, comprising a sedimentation feeding platform, a half-section partition, a long arm, a light-shielding plate, a support, a central holding area, and a testing channel. The central holding area is located at the center of the screening device; the support is located within the central holding area, and the light-shielding plate is suspended above the central holding area via the support; two long arms are parallel to each other to form the testing channel, and multiple testing channels are radially distributed around the periphery of the central holding area. One end of each testing channel is connected to the central holding area, and the other end is closed. Multiple half-section partitions are staggered within the testing channel, and the sedimentation feeding platform is located at the closed end of the testing channel.

[0005] Furthermore, the long arms are detachably connected to the side wall of the central temporary storage area via fixed slots, so that the test channels formed inside each long arm are connected to the central temporary storage area.

[0006] Furthermore, the sinking feeding platform is detachably connected to the test channel to facilitate the recovery of uneaten bait.

[0007] The present invention also provides a method for comprehensive evaluation of palatability attractants based on the screening device described in any one of the above claims, comprising the following steps: (1) The narrow-clawed crayfish were placed in the central temporary holding area to adapt to the environment, and the same amount of the attractant to be tested was simultaneously added to each of the sinking feeding platforms. The placement position of the attractant was rotated in multiple tests. (2) Conduct short-term behavioral observations: During the initial observation period after feeding, record the incubation period of the first feeding of the narrow-clawed crayfish when it first leaves the central holding area due to the attraction of odor. T 0, and record the number of valid individuals of narrow-clawed crayfish that first crossed the first half of the partition and entered each test channel to calculate the first selection rate. CR f , CR f = (Number of shrimp entering the channel for the first time / Total number of shrimp) × 100%; (3) Long-term feeding amount determination: After the initial observation period, the long-term free feeding stage was entered. Subsequently, each settling feeding platform was disassembled to recover the residual food that had settled inside. After drying and weighing, the feeding amount of each test group was calculated. FI ; (4) The incubation period of the first feeding T 0. Initial selection rate CR f and food intake FI Substituting into the comprehensive evaluation model, the comprehensive feeding attraction index is calculated, where the calculation formula of the comprehensive evaluation model is: , Where α is the initial feeding latency weight, β is the initial selection rate weight, and γ is the feeding amount weight, and α + β + γ = 1; T 0,min The shortest latency period among all test groups. CR max For the highest first-time selection rate, FI max The higher the overall appetite stimulating index, the greater the overall appetite stimulating potency of the group of appetite stimulants, representing the maximum food intake.

[0008] Furthermore, during multiple test cycles, the placement positions of each of the tested attractants on each settling feeding platform are periodically rotated to eliminate systematic errors caused by route memory generated by individual test subjects or differences in device position.

[0009] Compared with the prior art, the advantages of the present invention are as follows: 1. Low stress and high stability: This invention creates a light-proof environment that simulates natural dim light by setting a light-blocking plate above the central holding area. It makes full use of the crayfish's tendency to be attracted to darkness, so that it stably gathers in the central holding area at the beginning of the test. This effectively reduces the stress response and disordered activity caused by ambient light, and ensures the accuracy of behavioral observation.

[0010] 2. High throughput and flexible adjustment: The present invention adopts a radially distributed detachable long arm structure, which allows users to flexibly adjust the number of test channels (such as 2-6) according to actual test needs, realizing high-throughput parallel screening of multiple attractants, significantly improving screening efficiency, and facilitating cleaning and storage after the experiment.

[0011] 3. Multi-dimensional and precise evaluation: This invention innovatively combines short-term behavioral indicators (first-time feeding latency, first-time selection rate) with long-term feeding indicators (actual food intake) to construct a comprehensive appetite stimulant index (HAI) evaluation model. This model breaks through the limitations of traditional single directional tests, and can comprehensively and accurately quantify the combined efficacy of the "odor attractiveness" and "actual palatability" of appetite stimulants, avoiding false positive biases such as "smelling but not eating".

[0012] 4. Periodically rotate positions to prevent shrimp from developing route memory: This invention introduces a periodic position rotation mechanism in the method, which effectively prevents test individuals from developing directional feeding habits, ensuring that the experimental data comes entirely from the actual feeding effect of the attractant itself, rather than the shrimp's route memory, and greatly improving the reliability and repeatability of the screening results. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of the screening device for attractants for crayfish according to the present invention; Figure 2 This is a top view schematic diagram of the screening device for attractants for crayfish according to the present invention; Figure 3 This is an enlarged schematic diagram of the internal partial structure of the long-arm component in the screening device for attractants for crayfish of the present invention; Figure 4 This is a graph showing the comparative data of the comprehensive appetite stimulant index (HAI) of different appetite stimulants in this invention over a continuous testing period. The markings in the diagram are as follows: 1-Sinking feeding platform; 2-Half-section partition; 3-Long arm; 4-Fixing slot; 5-Light shield; 6-Bracket; 7-Central temporary holding area; 8-Testing channel. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0015] Example 1: Screening device for attractants suitable for crayfish.

[0016] like Figures 1 to 3 As shown in the figure, this embodiment provides a screening device for attractants suitable for crayfish. The device mainly includes: a settling feeding platform 1, a half-section partition 2, a long arm 3, a fixing slot 4, a light-shielding plate 5, a support 6, a central holding area 7, and a testing channel 8.

[0017] The central holding area 7 is located at the center of the entire device, with an inscribed circle diameter of, for example, 50 cm. The support 6 is a cylinder (1.5 cm in diameter, 19.7 cm high), vertically positioned at the center of the central holding area 7. The light-shielding plate 5 is a circular plate with a diameter of 45 cm, supported by the support 6 and suspended directly above the central holding area 7. This design creates a dark, shaded area above the central holding area 7, with gaps at the top to maintain water circulation. This design satisfies the crayfish's preference for shade and benthic habits, greatly reducing environmental stress and disorderly movement caused by strong light exposure.

[0018] Two parallel long arms 3 form a test channel 8, with an effective internal space of 80 cm in length and 27.5 cm in width. Multiple test channels 8 (e.g., 6) are evenly radially distributed around the periphery of the central holding area 7. One end of each test channel 8 is connected to the central holding area 7, while the other end is closed. The overall external length of each long arm 3 is 80 cm, the height is 20 cm, and the sidewall thickness is 0.3 cm. The end of each long arm 3 closest to the central holding area 7 is detachably connected to the sidewall of the central holding area 7 via a fixing slot 4. The external dimensions of the fixing slot 4 are 1 cm in length, 0.75 cm in width, and 19.7 cm in height, and the internal dimensions of the slot opening are 0.75 cm in length, 0.5 cm in width, and 19.7 cm in height.

[0019] Within test channel 8, multiple half-section partitions 2 (15 cm long, 19.7 cm high, and 0.3 cm thick) are fixed in an alternating manner. The half-section partitions 2 are set perpendicular to the long arm 3. The half-section partitions 2 are used to block linear vision, slow down the diffusion of odor in the water in a still water environment, ensure the independence of the odor gradient in each channel, and increase the randomness of the test individual's choice of channel.

[0020] At the end of test channel 8 (i.e., the end of long arm 3 furthest from the central holding area 7), a settling feeding platform 1 is installed. It has an outer diameter of 20 cm, an inner diameter of 18 cm, and a height of 1 cm. This platform is used to limit local water disturbance, allowing attractants and uneaten food to settle internally. The settling feeding platform 1 is detachably connected to long arm 3, facilitating removal of the entire platform after the experiment for uneaten food recovery.

[0021] Optionally, a camera (not shown in the figure) can be mounted above the device, with its monitoring range covering the entire device and all test channels, to record the entire experimental process for subsequent data statistics. The dimensions of the above components can be specifically set according to actual construction requirements, and no specific limitations are imposed in this application.

[0022] Example 2: Comprehensive evaluation method.

[0023] This embodiment provides a comprehensive evaluation method for attractants based on the device described in Embodiment 1. The specific steps are as follows: Step 1: Experimental Preparation and Design of Anti-Targeted Feeding Twelve healthy narrow-clawed crayfish, after a 24-hour fasting period, were placed in the central holding area 7 and allowed to acclimatize for 30 minutes under the shade created by the light-blocking plate 5. The total testing period was set at 24 days, with feeding tests conducted once a day. Before each daily test, equal amounts of the test attractant or control feed were simultaneously added to six settling feeding platforms 1. To prevent the crayfish from developing directional feeding habits, the placement of each attractant in the six test channels 8 was rotated one space clockwise each day. Within the 24 days, a complete rotation cycle was performed every 6 days (ensuring each formula was tested in all positions once), for a total of four cycles of continuous dynamic monitoring.

[0024] Step 2: Short-term behavioral observation Observation began immediately after feeding. The time when each crayfish first left the central holding area 7 and entered any test channel 8 after being attracted by the scent was recorded as the incubation period for first feeding. T 0. Simultaneously, record the number of individuals that successfully cross the first half-section partition 2 and enter each testing channel 8 for the first time. Calculate the first-selection rate for each group based on the total number of live subjects tested daily (12 individuals): CR f = (Number of shrimp entering the channel for the first time / 12) × 100%.

[0025] Step 3: Long-term food intake determination After a single feeding cycle (e.g., 24 hours), the sedimentation feeding platform 1 is disassembled and removed as a whole, and the uneaten food that has settled inside is collected. The uneaten food is dried to constant weight, and after deducting water-soluble losses, it is accurately weighed to calculate the true absolute feed intake for each test group per day. FI .

[0026] Step 4: Calculate the Comprehensive Appetite Intensity Index (HAI) The 24-day data was divided into four evaluation nodes, with each node defined as a 6-day period. The results for each period were calculated separately. T 0、 CR f and FI The average value. Considering the decisive role of prolonged feeding in actual aquaculture growth, this embodiment assigns weighting coefficients of 0.2, 0.3, and 0.5 to the latency period, first-selection rate, and feed intake. Four periods were selected. T 0 minimum value CR f and FI The maximum value, i.e. T 0,min , CR max and FI max Then substitute the values ​​into the following formula to calculate:

[0027] like Figure 4 As shown, after rigorous anti-targeted feeding tests and HAI model evaluations using this device, although the chemically synthesized compound DMPT is highly irritating and has a long latency period ( T The 0) group had the shortest selection rate, but due to a lack of natural palatability, its selection rate and actual consumption amount performed only moderately in the test. In contrast, the natural "shrimp paste group," with its optimal selection rate and consumption amount, consistently ranked first in HAI comprehensive scores over four consecutive cycles (0.946, 0.978, 0.955, and 0.967 respectively), demonstrating an extremely excellent and stable targeted feeding-promoting effect. Experimental results prove that the evaluation device and method of this invention successfully overcome the major deficiency of traditional mazes, which only evaluate "short-term olfactory attraction" while neglecting "long-term real palatability."

[0028] The foregoing description is not intended to limit the invention, nor is the invention limited to the examples given. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the invention should also be considered within the protection scope of the invention.

Claims

1. A screening device for attractants suitable for crayfish, characterized in that: The device includes a sinking feeding platform, half-section partitions, long arms, a light-shielding plate, a support frame, a central holding area, and a testing channel. The central holding area is located at the center of the screening device. The support frame is located within the central holding area, and the light-shielding plate is suspended above the central holding area via the support frame. Two long arms are parallel to each other to form the testing channel. Multiple testing channels are radially distributed around the periphery of the central holding area. One end of each testing channel is connected to the central holding area, and the other end is closed. Multiple half-section partitions are staggered within the testing channel, and the sinking feeding platform is located at the closed end of the testing channel.

2. The screening device for attractants suitable for crayfish according to claim 1, characterized in that: The long arms are detachably connected to the side wall of the central temporary storage area via fixed slots, so that the test channels formed inside each long arm are connected to the central temporary storage area.

3. The screening device for attractants suitable for crayfish according to claim 1, characterized in that: The sinking food platform is detachably connected to the test channel.

4. A method for comprehensive evaluation of palatability-inducing agents based on the screening device according to any one of claims 1-3, characterized in that... Includes the following steps: (1) The narrow-clawed crayfish were placed in the central temporary holding area to adapt to the environment, and the same amount of the attractant to be tested was simultaneously added to each of the sinking feeding platforms. The placement position of the attractant was rotated in multiple tests. (2) Conduct short-term behavioral observations: During the initial observation period after feeding, record the incubation period of the first feeding of the narrow-clawed crayfish when it first leaves the central holding area due to the attraction of odor. T 0, and record the number of valid individuals of narrow-clawed crayfish that first crossed the first half of the partition and entered each test channel to calculate the first selection rate. CR f , CR f = (Number of shrimp entering the channel for the first time / Total number of shrimp) × 100%; (3) Long-term feeding amount determination: After the initial observation period, the long-term free feeding stage was entered. Subsequently, each settling feeding platform was disassembled to recover the residual food that had settled inside. After drying and weighing, the feeding amount of each test group was calculated. FI ; (4) The incubation period of the first feeding T 0. Initial selection rate CR f and food intake FI Substituting into the comprehensive evaluation model, the comprehensive feeding attraction index is calculated, where the calculation formula of the comprehensive evaluation model is: Where α is the initial feeding latency weight, β is the initial selection rate weight, and γ is the feeding amount weight, and α + β + γ = 1; T 0,min The shortest latency period among all test groups. CR max For the highest first-time selection rate, FI max The higher the overall appetite stimulating index, the greater the overall appetite stimulating potency of the group of appetite stimulants, representing the maximum food intake.

5. The method for comprehensive evaluation of palatability enhancers according to claim 4, characterized in that: During multiple test cycles, the placement positions of the various test attractants on each settling feeding platform were rotated sequentially and periodically.

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