A method for identifying the sex of giant salamanders in the early reproductive period based on differences in respiratory behavior

Abstract

The present invention discloses a method for identifying the sex of sexually mature giant salamanders in an ecologically simulated breeding pond. Infrared cameras are installed above both sides of the ecologically simulated breeding pond and in the giant salamander's inhabiting cave to record the giant salamander's respiratory behavior and activity process in different time periods, and the start time and end time of each breath of the giant salamander are recorded to obtain the single breath duration, breath interval, breath frequency and total breath duration of each time period of the respiratory behavior. Paired sample T test is used to compare the respiratory differences of individual giant salamanders during day and night time periods. The sex of the giant salamanders is identified based on the differences in respiratory indicators, thereby accurately determining the male-female ratio when pairing parents during giant salamander breeding.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and more particularly relates to a method for identifying the sex of sexually mature giant salamanders based on differences in respiratory behavior. Background Art

[0002] The giant salamander (Andrias davidianus) belongs to the genus Andrias, family Cryptobranchidae, order Caudata, class Amphibia, and is a rare animal endemic to China.

[0003] The giant salamander is an economic animal with extremely high edible and medicinal value. Its meat is tender and delicious, containing high-quality protein, rich amino acids and trace elements, and has the effects of nourishing yin and tonifying the kidneys, replenishing blood and promoting qi circulation. Therefore, the giant salamander is one of the key species developed in the agricultural industrialization. The ecological reproduction and artificial insemination technologies of giant salamanders are gradually maturing. The ideal male-female ratio for giant salamander reproduction is 1:1, but sex identification of giant salamanders has always been a difficult problem. In production, the inappropriate sex ratio often results in low egg-laying and fertilization rates during natural reproduction. Currently, identifying the sex of mature giant salamanders by cloaca morphology during the breeding season is a relatively effective method, but the accuracy rate is not high, especially when the gonads of giant salamanders are poorly developed, and the error rate is even higher. In addition, Ou Dongsheng et al. (2007) (Ou Dongsheng, Deng Zhiyong, How to determine the sex of Chinese giant salamander, Inland Fisheries, 2007, 271(7):33-34) proposed to identify sex based on appearance. If the head width is larger than the body width, it is male, and if the head width is significantly smaller than the body width, it is mostly female. However, body width varies greatly with the fatness or thinness of the animal, making it difficult to accurately determine. Some scholars have also proposed using ultrasound technology, hormone testing and other methods to identify sex (Li PQ, Zhu BC, Wang YF, et al. Sex identification of Chinese giant salamander (Andrias davidianus) by Doppler B-ultrasound. Journal of Biology, 2010. 231, 27(1):94-96. Tang Yabin et al. Several methods for sex identification of giant salamander parents, Chinese Fisheries, 2012, 443(10):67). These technologies all have operational difficulties.

[0004] Animal behavior encompasses everything an animal does to contribute to its immediate survival and future genetic continuity. It represents an animal's holistic response to physiological changes within its body and environmental changes outside its body. Respiration is fundamental to a species' survival and indicates its metabolic status. The lungs of giant salamanders are the primary respiratory organ, with the skin serving as a secondary respiratory organ. Using an infrared imaging monitoring system to study the respiratory behavior of giant salamanders during their early reproductive stages, researchers discovered significant differences between the lungs of male and female giant salamanders. This finding could provide technical support for sex differentiation in artificial breeding of giant salamanders. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for identifying the sex of giant salamanders in the early breeding period. By observing the respiratory behavior of giant salamanders and comparing and analyzing the differences in lung respiratory behavior of male and female giant salamanders in the early breeding period, the sex of giant salamanders can be effectively identified.

[0006] To achieve the above technical objectives, the embodiment of the present invention is: a method for identifying the sex of giant salamanders in the early reproductive stage based on differences in respiratory behavior, comprising:

[0007] 1. Select a certain number of healthy and mature giant salamanders and raise them in an ecological breeding pond;

[0008] 2. Install infrared cameras above the giant salamander ecological breeding pond and inside the giant salamander's cave, respectively, to record the giant salamander's breathing behavior and activities inside and outside the simulated ecological breeding pond;

[0009] 3. During the 45-day observation period, observations were conducted every 2 days, with each intermittent observation lasting 24 hours. The observation time was evenly distributed into 4-8 observation periods, and each observation period was evenly distributed between day and night. The observation duration and interval length of each observation period were the same;

[0010] 4. The process of the giant salamander raising its head above the water to inhale and sinking back into the water to exhale is considered a complete lung breathing behavior. The start and end time of each breath are recorded through the video, and the single breath duration, breathing interval, breathing frequency and total breathing time of each time period are obtained;

[0011] 5. Paired sample T test was used to compare the respiratory differences of giant salamanders during the day and night time periods, as well as the daily average differences in the respiratory indicators of giant salamanders. Female salamanders were identified as having the following respiratory characteristics: the breathing interval was shorter during all observation periods, the respiratory frequency was higher in all time periods except the period from 18:00 to 20:00 in the evening, the duration of a single breath was shorter from 2:00 to 4:00 in the morning, and the total breathing duration was longer from 10:00 to 12:00 in the afternoon; male salamanders had the opposite respiratory characteristics.

[0012] As an optimized implementation method, the 24 hours of intermittent observation are divided into 6 time periods, each time period is 2 hours, specifically: 6:00-8:00, 10:00-12:00 and 14:00-16:00; 18:00-20:00, 22:00-24:00 and 2:00-4:00.

[0013] As a more specific implementation, the duration of a single breath = the end time of breathing - the start time of breathing; the breathing interval = the start time of this breath - the end time of the previous breath; the breathing frequency = the number of breaths / hour; the total breathing duration of each time period = the duration of a single breath in each time period × the breathing frequency in each time period.

[0014] As a more specific implementation method, in step 2, the infrared cameras outside the cave are installed above both sides of the giant salamander ecological breeding pond to capture the entire artificial stream, and the infrared cameras inside the cave are installed in each giant salamander habitat cave.

[0015] As a further optimized implementation method, the in-cave camera is installed on the side wall of the giant salamander's habitat cave close to the giant salamander's ecological breeding pond, and can capture the activities of the giant salamander in the entire giant salamander's habitat cave.

[0016] As an optimized implementation method, an observation hole is set 50 to 60 cm above the side of the giant salamander's habitat cave close to the artificial stream, through which the camera inside the cave can be observed.

[0017] As an optimized implementation method, the infrared camera outside the cave and the camera inside the cave are ICR infrared filter type infrared wide-angle cameras with 2 to 4 million pixels, infrared irradiation distance of 30 to 50 meters, minimum illumination of 0 Lux, and operating temperature of -30℃ to 60℃.

[0018] The present invention's research shows that the respiratory behavior of both female and male salamanders in the early reproductive period has obvious circadian rhythm changes: at night, the duration of a single breath is long, the breathing interval is short, the breathing frequency is high, and the total breathing duration is longer, while the opposite is true during the day. Compared with male salamanders, female salamanders have more vigorous respiratory metabolism. Male salamanders are more active, and their single breath duration is longer than that of female salamanders, but their breathing frequency is low, the intervals are long, and the total breathing duration is short. In the early reproductive period, the breathing of male salamanders fluctuates greatly during the day and night, while the breathing of female salamanders is more stable. The present invention observes the respiratory behavior of giant salamanders through an image monitoring system, compares and analyzes the differences in the lung respiratory behavior of male and female giant salamanders in the early reproductive period, can effectively identify the sex of giant salamanders, and can accurately determine the male-to-female ratio when pairing giant salamander parents. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is a diagram of the installation of the giant salamander ecological breeding pond and infrared camera. 1-Giant salamander ecological breeding pond, 2-Infrared camera outside the cave, 3-Infrared camera inside the cave, 4-Giant salamander habitat cave, 5-Observation hole, 6-Water inlet pipe, 7-Water outlet pipe, 8-Post

[0020] Figure 2 The paired sample T test shows the single breathing duration, breathing interval, breathing frequency and total breathing duration in each time period of the giant salamander's breathing behavior. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with specific embodiments:

[0022] 1. Rearing conditions

[0023] like Figure 1 As shown, the experimental site is an artificial stream, approximately 22m long, 1.10m wide, and 0.40m deep. The water source is flowing mountain spring water. Multiple giant salamander ecological breeding ponds 1 are evenly distributed along the artificial stream. Each pond is equipped with an inlet pipe 6 and an outlet pipe 7. A giant salamander habitat cave 4 is set at the bottom of each ecological breeding pond 1. Each cave has an area of ​​approximately 1.44m 2 The cave entrance is approximately 0.25m high and 0.30m wide, with a water depth of approximately 0.20m. The cave floor is composed of sand and pebbles. An observation hole 5 was installed 50-60cm above the artificial stream side of the cave.

[0024] 2. Experimental Giant Salamanders: Six healthy giant salamanders were randomly selected. They weighed 9.80 kg to 12.20 kg, were 1.12 m to 1.26 m in length, and were 9 to 10 years old. They were housed in a giant salamander ecological breeding pond and were allowed to freely choose their own burrows.

[0025] 3. Instruments used in the experiment

[0026] The infrared camera is HIK vision, DS-2CD3T35D-I5, produced by Hangzhou Hikvision Digital Technology Co., Ltd. Figure 1 As shown, an infrared camera 3 inside the cave is mounted on the wall of the giant salamander's habitat cave 4, near the giant salamander's ecological breeding pond 1. The camera 3 is visible through an observation hole 5. An infrared camera 2 outside the cave is mounted on columns 8 above the habitat stream on either side, at an optimal height to capture the entire artificial stream. The infrared camera 3 inside the cave and the camera 2 outside the cave record the giant salamander's breathing behavior and activities inside and outside the simulated ecological breeding pond.

[0027] 4. Observation method

[0028] During the 45-day observation period, the animals were observed every two days for 24 hours (including the intervals), for a total of 15 days. Observations were conducted during six 2-hour periods each day: 6:00–8:00 AM, 10:00–12:00 PM, and 2:00–4:00 PM; 6:00–8:00 PM, 10:00–12:00 PM, and 2:00–4:00 AM. Respiratory behavior indices were recorded for three pairs of male and female salamanders. These indices include the duration of a single breath, the interval between breaths, the respiratory rate, and the total duration of breaths during each period.

[0029] 5. Respiratory behavior observation indicators

[0030] The process of the giant salamander raising its head above the water to inhale and then sinking back into the water to exhale is considered a complete lung breathing behavior. The start and end times of each breath were recorded through video. The duration of a single breath, breathing interval, respiratory rate, and total breathing time for each time period were calculated. Single breath duration = breath end time - breath start time; breathing interval = current breath start time - previous breath end time; respiratory rate = breaths / hour; total breathing time for each time period = single breath duration in each time period × respiratory rate in each time period.

[0031] 6. Differences in respiratory behavior between male and female giant salamanders during the early reproductive period

[0032] Paired sample T test showed that ( Figure 2 The duration of a single breath in female salamanders was significantly shorter than that in males between 2:00 and 4:00 a.m. (P < 0.05), with no significant differences in the other five time periods. The respiratory intervals of female salamanders were significantly shorter than those of males in all six time periods during the day and night (P < 0.05). With the exception of the evening time period of 6:00 p.m. to 8:00 p.m., the respiratory frequency of female salamanders was significantly greater than that of males in the other five time periods (P < 0.001). The total respiratory duration of female salamanders was significantly greater than that of males between 10:00 a.m. and 12:00 p.m. (P < 0.01), with no significant differences in the other five time periods.

[0033] Based on the above-mentioned differences in respiratory behavior between male and female giant salamanders in the early stage of reproduction, the sex of the giant salamander can be accurately determined, so as to accurately determine the male-female ratio when pairing the giant salamander breeding parents.

Claims

1. A method for identifying the sex of giant salamanders in the early reproductive stage based on differences in respiratory behavior, characterized in that: include: a. Select a certain number of healthy and mature giant salamanders and raise them in a giant salamander ecological breeding pond; b. Install infrared cameras above the giant salamander ecological breeding pond and inside the giant salamander's cave, respectively, to record the giant salamander's breathing behavior and activities inside and outside the cave; c. During the 45-day observation period, observations were conducted every 2 days, with each intermittent observation period lasting 24 hours, evenly distributed into 4-8 observation periods, with each observation period evenly distributed between day and night, and the observation duration and interval length of each observation period being the same; d. The process of the giant salamander raising its head above the water to inhale and sinking back into the water to exhale is considered a complete lung breathing behavior. The start and end time of each breath are recorded through the video, and the single breath duration, breathing interval, breathing frequency and total breathing time of each time period are obtained; e. Paired sample T-tests were used to compare the respiratory differences of individual giant salamanders during the day and night time periods, as well as the daily average differences in respiratory indicators of individual giant salamanders. Female salamanders were identified as having the following respiratory characteristics: the breathing interval was shorter during all observation periods, the respiratory frequency was higher in all time periods except the period from 18:00 to 20:00 in the evening, the duration of a single breath was shorter between 2:00 and 4:00 in the morning, and the total breathing duration was longer between 10:00 and 12:00 in the afternoon; The male salamander has the opposite respiratory characteristics.

2. The method for identifying the sex of giant salamanders in the early reproductive stage based on respiratory behavior differences according to claim 1, wherein: The 24 hours of intermittent observation were divided into 6 time periods, each of which lasted 2 hours, specifically 6:00-8:00, 10:00-12:00, and 14:00-16:00; 18:00~20:00, 22:00~24:00 and 2:00~4:

00.

3. The method for identifying the sex of giant salamanders in the early reproductive stage based on respiratory behavior differences according to claim 1, wherein The duration of a single breath = the end time of breathing - the start time of breathing; the breathing interval = the start time of this breath - the end time of the previous breath; the breathing frequency = the number of breaths / hour; the total breathing duration of each time period = the duration of a single breath in each time period × the breathing frequency in each time period.

4. The method for identifying the sex of giant salamanders in the early reproductive stage based on respiratory behavior differences according to claim 1, wherein: In step b, the infrared cameras (2) outside the cave are installed above both sides of the giant salamander ecological breeding pond (1), and the infrared cameras (3) inside the cave are installed in each giant salamander habitat cave (4).

5. The method for identifying the sex of giant salamanders in the early reproductive stage based on respiratory behavior differences according to claim 1 or 4, wherein: The infrared camera (3) in the cave is installed on the side wall of the giant salamander habitat cave (4) close to the giant salamander ecological breeding pond (1).

6. The method for identifying the sex of giant salamanders in the early reproductive stage based on respiratory behavior differences according to claim 1, wherein: An observation hole was set up 50-60 cm above the artificial stream side of the giant salamander's burrow (4).

7. The method for identifying the sex of giant salamanders in the early reproductive stage based on respiratory behavior differences according to claim 1, wherein: The infrared camera outside the cave (2) and the infrared camera inside the cave (3) are ICR infrared filter type infrared wide-angle cameras with 2 to 4 million pixels, an infrared irradiation distance of 30 to 50 meters, a minimum illumination of 0 Lux, and an operating temperature of -30°C to 60°C.

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