A method for improving the mating rate of penaeus vannamei

Abstract

A method for improving the mating rate of Penaeus vannamei, comprising the following steps: step one, cultivating diatoms in a parent culture pond: scraping the naturally propagated benthic diatoms from the inner wall of the water inlet pipeline in the breeding field or near the middle tide line of the beach to obtain the benthic diatom liquid; culturing the benthic diatoms in still water: continuously adding filtered seawater to culture the benthic diatoms by flowing water; and culturing in a pond: moving female and male parent shrimps into the parent culture pond in which the benthic diatoms are cultivated until the female shrimps mature; step two, moving the female shrimps into the male shrimp culture pond for mating: selecting the female shrimps with mature gonads and moving them into the male shrimp culture pond for mating; step three, moving the female shrimps that have successfully mated into an egg laying pond for laying eggs, and taking out the female shrimps after laying eggs and returning them to the original culture pond. The method stabilizes the water quality by managing the benthic diatoms in the culture pond, provides a stable mating environment, and improves the mating rate; the operation is simple, the parent shrimps are less damaged, the cost is lower, the success rate is high, and the mating rate is as high as 90%.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of white shrimp Penaeus vannamei cultivation, in particular to a method for improving the mating rate of white shrimp Penaeus vannamei. BACKGROUND

[0002] Litopenaeus vannamei, belonging to Crustacea, Penaeidae and Penaeidae, is also known as white shrimp Penaeus vannamei, which is originally produced in Ecuador near the equator of the Pacific Ocean of South America and introduced into China in the 1990s. White shrimp Penaeus vannamei has thin shell, delicious meat, wide temperature and salt range, fast growth rate, strong stress resistance and high-density cultivation resistance. As one of the three major shrimps with the widest cultivation range and the highest yield in the world, the breeding of white shrimp Penaeus vannamei has important practical significance for the development of the shrimp cultivation industry.

[0003] As the largest white shrimp Penaeus vannamei cultivation country in the world, China has a huge demand for white shrimp Penaeus vannamei fry, and large-scale breeding technology is the key to the healthy and sustainable development of the white shrimp Penaeus vannamei cultivation industry in China. Improving the mating rate of parent shrimp through artificial intervention is one of the important technologies for white shrimp Penaeus vannamei seed breeding. At present, the mating of female and male parent shrimps of white shrimp Penaeus vannamei mainly adopts artificial insemination and natural mating. The artificial insemination method is to squeeze the mature sperm of male shrimp and adhere to the female sperm receptacle. This method is complicated, harmful to parent shrimp and not suitable for large-scale production. The natural mating method is to separate female and male parent shrimps for breeding, and then put mature female shrimps into male shrimp breeding ponds for free mating. In the process of natural mating, in order to maintain good water quality, daily pool cleaning, water changing and pollution cleaning are required. The continuous moving of female shrimps in and out of the male shrimp pool leads to great changes in the breeding environment, high elimination rate of female shrimps, low and unstable mating rate, generally 20%-70% change. Therefore, the white shrimp Penaeus vannamei seed breeding industry urgently needs a method for improving the mating rate of white shrimp Penaeus vannamei on the basis of reducing the harm to parent shrimps.

[0004] In view of the above problems, the present application provides a method for improving the mating rate of white shrimp Penaeus vannamei, which is simple in operation and can significantly improve the survival rate and mating rate of parent shrimps, improve the fertilization rate and prolong the breeding period. SUMMARY

[0005] The present application provides a method for improving the mating rate of white shrimp Penaeus vannamei.

[0006] The technical scheme of the present application is as follows: a method for improving the mating rate of white shrimp Penaeus vannamei, comprising the following steps:

[0007] Step one, cultivation of diatom on the bottom of parent breeding pond:

[0008] Algal species and source: from the inner wall of the water pipeline in the breeding field or near the middle tide line of the beach, scrape the naturally proliferated benthic diatoms, put them into a plastic bucket, add clean filtered seawater, stir and remove impurities, stand for a while, take the upper layer of tea-brown liquid through a silk screen filter to obtain the benthic diatom algal liquid;

[0009] Parent culture pool water inlet, inoculation of benthic diatoms: the culture pool is a 5m x 6m x 1.3m indoor cement pool, add filtered seawater, pour the collected benthic diatom algal liquid into the culture pool, stop aeration after about 10 minutes of micro-aeration, stand for 24 hours, and make the benthic diatoms deposit at the bottom of the pool;

[0010] Static water culture of benthic diatoms: continuously add filtered seawater to maintain a water depth of about 0.6m, use flowing water to culture benthic diatoms, replace fresh seawater and fertilize every 2-3 days, and flush away the pool bottom dirt when replacing water

[0011] Step two, pool culture

[0012] (1) Culture conditions: move female and male parent shrimps into the parent culture pool with cultured benthic diatoms until the female shrimps mature;

[0013] (2) Maintenance of benthic diatoms: observe the concentration of diatoms, that is, the transparency of the culture pool water, and maintain the transparency at about 50cm, replace water once in the morning and evening every day, and the replacement amount is 50-100%;

[0014] Step three, mating of female and male parent shrimps: move female shrimps into the male shrimp culture pool for mating: select female shrimps with mature gonads and move them to the male shrimp culture pool for mating;

[0015] Step four, spawning and hatching of fertilized eggs: move successfully mated female shrimps to the spawning pool for spawning, the female shrimp density in the spawning pool is 4-6 / m 2 , the seawater in the spawning pool is strictly filtered and kept in a micro-aerated state, and the density of fertilized eggs does not exceed 500,000 / m 3 , and the female shrimps after spawning are removed and returned to the original culture pool.

[0016] In step one, observe the benthic diatom algal liquid under a microscope to determine whether it is diatom, coconeis, navicula, and oval algae, etc. beneficial algae, otherwise take the benthic diatom algal liquid again.

[0017] In step one, the light intensity in the static water culture of benthic diatoms is controlled at 300-500 lux, and the benthic diatoms are cultured for 7-15 days, and the bottom is light yellow, that is, the transparency of the culture pool water is maintained at about 50cm.

[0018] The mating condition in the step three: before the female prawns are moved into the male prawn breeding pool, 80% of the water in the male prawn breeding pool is changed, and the pool water depth is kept at 50-70 cm; the illumination is the same as the breeding condition, the illumination intensity is 500-1000 lux in the daytime, and the daylight lamp above the breeding pool needs to be turned on for illumination in the night, and the illumination is controlled at 300-500 lux; the female-male ratio is about 1:1.5 during mating.

[0019] The female prawns are moved out in the step three: the mating generally lasts for 3-5 hours; after the mating, the successfully mated female prawns can be observed to have the spermatophore adhered to the position of the spermatophore between the 3rd-4th pairs of walking legs on the chest of the female prawns, the successfully mated female prawns are put back into the female prawn breeding pool for further cultivation, and can continue to mate when sexually mature.

[0020] In the step two, the female and male parent prawns are bred in separate pools, the dissolved oxygen is kept above 5 mg / L, the seawater specific gravity is 1.016-1.025, the pH value is 8.0-8.5, the water temperature is 25-28℃, and the breeding density is 10 tails / m 2 ~ 15 tails / m 2 ;

[0021] (2) Feeding and nutrition strengthening: the daily feeding amount of the feed is 7%-15% of the body weight of the prawns during the strengthening breeding; the artificial maturation is performed for more than 18-20 days;

[0022] (3) Artificial maturation: the water temperature of the breeding pool is gradually increased, the temperature is increased by no more than 0.5℃ per day, and when the temperature reaches 27-30℃, the temperature is kept constant, one side of the eye stalk of the female prawn is burned by the scalding method,

[0023] In the step two, the sandworm, red worm, oyster and squid are used as the feed for the nutrition strengthening breeding.

[0024] Beneficial effects: the present application stabilizes the water body environment by breeding benthic diatoms, controls the mating of parent prawns in the whole process, and establishes an ecological, environmentally-friendly and biologically safe South American white prawn breeding technology, which significantly improves the mating rate of the South American white prawn on the basis of reducing the damage to the parent prawns, and has remarkable ecological and economic benefits. The present application has the following characteristics:

[0025] (1) The benthic diatoms in the breeding pool are managed to stabilize the water quality, and a stable mating environment is provided for the parent prawns of the South American white prawn, so that the mating rate of the South American white prawn is improved;

[0026] (2) The parent prawns of the South American white prawn are selected for breeding in separate pools, and the parent prawns are nutritionally strengthened to reach the best state, so that the mating rate of the South American white prawn is improved;

[0027] (3) The female and male parent prawns are respectively matured, so that the parent prawns reach sexual maturity at the same period, and the mating rate of the South American white prawn is improved;

[0028] (4) Simple operation: little damage to parent shrimp; low cost; high success rate: mating rate up to 90%. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0030] It should be noted that the description of "first", "second" and the like in the present application is only for the purpose of description and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can realize it. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0031] 1. Cultivation of parent diatoms:

[0032] (1) Algal species and sources: scrape the naturally proliferated benthic diatoms from the inner wall of the water inlet pipeline in the breeding field or near the middle tide line of the beach, put them into a plastic bucket, add clean filtered seawater, stir and remove impurities, stand for a while, take the upper tea-brown liquid through a silk screen filter, obtain the benthic diatom algal liquid, and observe under a microscope to be diatoms, coconeis, navicula, and oval algae.

[0033] (2) Water inlet of parent culture pond and inoculation of benthic diatoms: select a 5m x 6m x 1.3m indoor cement pond in the parent shrimp breeding workshop in Jiaowei Township, Xuwen County, Zhanjiang City, Guangdong Province as the parent culture pond, add filtered seawater, pour the collected benthic diatom algal liquid into the culture pond, and stop aeration after about 10 minutes of micro-aeration, stand for 24 hours, and make the benthic diatoms deposit at the bottom of the pond.

[0034] (3) Static water culture of benthic diatom: continuously add filtered seawater to maintain a water depth of about 0.6 m, use flowing water to culture benthic diatom, replace fresh seawater and fertilize every 2-3 days, and flush the pool bottom dirt when replacing water. Fertilize according to the conventional benthic diatom culture solution formula, add to the seawater in the culture tank, and gently stir to make it uniform. Adjust the light intensity to control at 300-500 lux, adjust the skylight or side window of the culture room to keep the indoor diffuse light strong, prevent direct sunlight, and periodically check under the microscope to understand the growth and reproduction of the cultured algae. After 10 days of culture, the bottom is light yellow, and the water transparency of the culture tank is maintained at about 50 cm.

[0035] 2. Parental shrimp culture

[0036] (1) Culture conditions: select 9-month-old healthy and robust parent shrimps (average weight 35 g per tail) and place them in the parental culture tank with benthic diatom, the dissolved oxygen in the parental culture tank is maintained at more than 5 mg / L, the seawater specific gravity is 1.016-1.025, the pH value is 8.0-8.5, the water temperature is 25-28°C, and the culture density is 10 tails / m2, i.e. 300 tails per tank.

[0037] (2) Feeding and nutritional enhancement: use sandworms, red worms, oysters, and squid as feed to enhance nutrition, the daily feeding amount during the enhancement process is 10% of the body weight of the shrimp, i.e. 1.05 kg of feed per tank per day; the water in the culture tank meets or exceeds the GB11607 standard and has been strictly filtered and disinfected. After more than 20 days of nutritional enhancement culture, artificial maturation can be performed.

[0038] (3) Artificial maturation: gradually increase the water temperature in the culture tank, the daily temperature increase should not exceed 0.5°C, and when the temperature reaches 28-29°C, maintain a constant temperature, and use the scalding method to clamp one side of the female shrimp's eye stalk to promote the maturation of the female shrimp's gonads.

[0039] (4) Maintenance of benthic diatom: observe the concentration of diatom, i.e. the water transparency of the culture tank, maintain the transparency at about 50 cm, replace the water twice a day, the replacement amount is 50%, and when replacing the water, only the pool bottom dirt and the aged and shed benthic diatom need to be flushed away. The self-dissolved nutrients in the water can meet the nutritional needs of benthic diatom, and no additional fertilization is needed during the culture period.

[0040] 3. Mating of female and male parent shrimps

[0041] (1) Move female shrimps to male shrimp tank for mating: the gonads of parent shrimps will gradually mature within 3-7 days after maturation surgery, check the development every day, and move 208 mature female shrimps to the male shrimp culture tank for mating at 16:00-17:00 in the afternoon, with a female to male ratio of about 1:1.5.

[0042] (2) Mating conditions: before the female prawns are moved into the male prawn breeding pool, 80% of the water in the male prawn breeding pool is changed, and the pool water depth is kept at 50-70 cm; the light is the same as the breeding condition, the light intensity is 500-1000 lux during the day, and the overhead daylight lamp needs to be turned on at night, and the light intensity is controlled at 300-500 lux; the ratio of female to male in the mating pool is about 1:1.5; do not disturb the parent prawns during mating to avoid affecting the mating activity; and the female prawns that have mated are transferred in time, and the sperm of the male prawns is easy to fall off after multiple chases.

[0043] (3) Moving out female prawns: mating generally lasts for 3-5 hours; after mating, the successfully mated female prawns can be observed to have the sperm of the male prawns adhered to the position of the spermatophore between the 3rd-4th pairs of walking legs on the chest of the female prawns, and the female prawns that have not successfully mated are returned to the female prawn breeding pool for further cultivation, and can continue to mate when sexually mature.

[0044] 4. Egg production and fertilized egg hatching:

[0045] The successfully mated female prawns are transferred to the egg production pool for egg production, the female prawn density in the egg production pool is 4-6 per m2, the seawater in the egg production pool is strictly filtered and kept in a slightly aerated state, the fertilized egg density is 400,000 per m3, and the female prawns after egg production are removed and returned to the original breeding pool.

[0046] 5. Using the breeding mode of the present application, the mating rate, egg production, egg return time, and hatching rate are counted starting from the first week of production, and the production effect is continuously counted for 10 days, on average, 75 parent prawns with mature gonads are selected every day, 61 successfully mated female prawns, the daily mating rate reaches 81.3%, the average egg production of each female prawn is 310,000, the female prawn egg return time is 4 days, and the fertilized egg hatching rate reaches 95.8%.

[0047] Example 2

[0048] 1. Cultivation of diatoms in parent breeding pool:

[0049] (1) Algae species and source: scrape the naturally proliferated benthic diatoms from the inner wall of the water inlet pipeline in the breeding field or near the middle tide line of the beach, put them into a plastic bucket, add clean filtered seawater, stir and remove impurities, stand for a while, take the upper brownish liquid through a silk screen filter, and obtain the benthic diatom algae liquid, which is observed under a microscope to be diatoms, chlorella, navicula, and oval algae.

[0050] (2) Water inlet and inoculation of benthic diatoms in parent breeding pool: select a 5m x 6m x 1.3m indoor cement pool in the parent prawn breeding workshop in Jiaowei Township, Xuwen County, Zhanjiang City, Guangdong Province as the parent breeding pool, add filtered seawater, pour the collected benthic diatom algae liquid into the breeding pool, and stop aeration after about 10 minutes of slight aeration, stand for 24 hours, and make the benthic diatoms deposit at the bottom of the pool.

[0051] (3) Static water culture of benthic diatom: continuously add filtered seawater to maintain a water depth of about 0.6 m, use flowing water to culture benthic diatom, replace fresh seawater and fertilize every 2-3 days, and flush the pool bottom dirt when replacing water. Fertilize according to the conventional benthic diatom culture solution formula, add to the seawater in the culture tank, and gently stir to make it uniform. Adjust the light intensity to control at 300-500 lux, adjust the skylight or side window of the culture room to keep the indoor diffuse light strong, prevent direct sunlight, and regularly check under the microscope to understand the growth and reproduction of the cultured algae. After 10 days of culture, the bottom of the benthic diatom is light yellow, and the water transparency of the culture tank is maintained at about 50 cm.

[0052] 2. Parental shrimp culture

[0053] (1) Culture conditions: select 9-month-old healthy and robust parent shrimps (average weight 30 g per tail) and place them in the parental culture tank with benthic diatom, the dissolved oxygen in the parental culture tank is maintained at more than 5 mg / L, the seawater specific gravity is 1.016-1.025, the pH value is 8.0-8.5, the water temperature is 25-28°C, and the culture density is 15 tails / m2, i.e. 450 tails per tank.

[0054] (2) Feeding and nutritional enhancement: use sandworms, red worms, oysters, and squid as feed to enhance nutrition, the daily feeding amount during the enhancement process is 15% of the body weight of the prawns, i.e. 2.1 kg of feed per tank per day; the water in the culture tank meets or exceeds the GB11607 standard and has been strictly filtered and disinfected. After more than 20 days of nutritional enhancement culture, artificial maturation can be carried out.

[0055] (3) Artificial maturation: gradually increase the water temperature in the culture tank, the daily temperature increase should not exceed 0.5°C, and when the temperature reaches 28-29°C, maintain a constant temperature, and use the scalding method to clamp one side of the female shrimp's eye stalk to promote the maturation of the female shrimp's gonads.

[0056] (4) Maintenance of benthic diatom: observe the concentration of diatom, i.e. the water transparency of the culture tank, maintain the transparency at about 50 cm, replace the water twice a day, the replacement amount is 50%, and when replacing the water, only the pool bottom dirt and the aging and shed benthic diatom need to be flushed away. The self-dissolved nutrients in the water can meet the nutritional needs of benthic diatom, and no additional fertilization is needed during the culture period.

[0057] 3. Mating of female and male parent shrimps

[0058] (1) Move female shrimps to male shrimp tank for mating: the gonads of parent shrimps will gradually mature within 3-7 days after maturation surgery, check the development every day, and move 300 female shrimps with mature gonads to the male shrimp culture tank for mating at 16:00-17:00 in the afternoon, with a female to male ratio of about 1:1.45.

[0059] (2) mating conditions: before the female prawns are moved into the male prawn breeding pond, 80% of the water in the male prawn breeding pond is changed, and the water depth is kept at 50-70 cm; the illumination is the same as the breeding condition, the light intensity is 500-1000 lux during the day, and the daylight lamp above the mating pond needs to be turned on at night, and the illumination is controlled at 300-500 lux; the ratio of female prawns to male prawns in the mating pond is about 1:1.5; the parent prawns should not be disturbed during mating to avoid affecting the mating activity; the female prawns that have mated are transferred in time, and the sperm castings are easy to fall off after the male prawns chase several times.

[0060] (3) removing female prawns: mating generally lasts for 3-5 hours; after mating, the female prawns that have successfully mated can be observed to have the sperm castings of male prawns adhered to the position of the spermatophore between the 3rd-4th pairs of legs on the chest of the female prawns, and the female prawns that have not successfully mated are returned to the female prawn breeding pond for further cultivation, and can continue to mate when sexually mature.

[0061] 4. spawning and hatching of fertilized eggs:

[0062] The female prawns that have successfully mated are transferred to the spawning pond for spawning, the density of female prawns in the spawning pond is 4-6 per m2, the seawater in the spawning pond is strictly filtered and kept in a slightly aerated state, the density of fertilized eggs is not more than 500,000 per m3, and the female prawns after spawning are removed and returned to the original breeding pond.

[0063] 5. Using the breeding mode of the present application, the mating rate, spawning quantity, egg returning time, and hatching rate of production effects are counted after 15 days of production, and the counting is continuously conducted for 15 days, on average, 110 parent prawns with mature gonads can be selected per day, 82 female prawns that have successfully mated can be selected per day, the daily mating rate reaches 74.5%, the average number of eggs produced by each female prawn is 330,000, the egg returning time of female prawns is 4.1 days, and the hatching rate of fertilized eggs reaches 96.1%.

[0064] The above is only the preferred embodiment of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A method of increasing the mating rate of Penaeus vannamei, characterized by: Includes the following steps: Step 1: Cultivation of benthic diatoms in the parent culture pond: Algae species and sources: Naturally reproduced benthic diatoms were scraped from the inner wall of the water inlet pipe in the breeding farm or near the midtide line of the beach, placed in a plastic bucket, clean filtered seawater was added, stirred and impurities were removed, and the mixture was left to stand for a while. The upper brownish liquid was then filtered through a silk screen to obtain the benthic diatom liquid. Water was introduced into the parent culture tank, and benthic diatoms were inoculated: The culture tank was an indoor cement tank of 5 m × 6 m × 1.3 m, with filtered seawater added. The collected benthic diatom liquid was poured into the culture tank, and aeration was stopped after about 10 minutes. The tank was left to stand for 24 hours to allow the benthic diatoms to settle at the bottom of the tank. Still water culture of benthic diatoms: Continuously add filtered seawater to maintain a water depth of about 0.6 m, use flowing water to cultivate benthic diatoms, change the seawater with fresh water and fertilize every 2 to 3 days, and flush away the dirt at the bottom of the pool when changing the water; Adjust the light intensity to 300-500 lux, and after 7 to 15 days of cultivation, the bottom of the benthic diatoms will be light yellow, and the water transparency of the cultivation tank will be maintained at about 50cm. Step 2: Culture in the pool Cultivation: Transfer the female and male parent shrimp into a parent rearing pond where benthic diatoms have been cultivated until the female shrimp's gonads mature; Maintenance of benthic diatoms: Observe the diatom concentration, i.e. the water transparency of the cultivation tank. The transparency should be maintained at about 50cm. Change the water twice a day, once in the morning and once in the evening, with a water replacement volume of 50-100%. Step 3: Mating of male and female parent shrimp: Transfer female shrimp to male shrimp rearing pond for mating: Select female shrimp with mature gonads and transfer them to male shrimp rearing pond for mating; Before female shrimp are transferred to male shrimp rearing ponds, 80% of the water in the male shrimp rearing ponds should be replaced, and the water depth should be maintained at 50-70cm. The lighting should be the same as the rearing conditions, with a daytime light intensity of 500-1000 lux and a nighttime light source of 300-500 lux above the rearing ponds. The female-to-male ratio should be 1:1.5 during mating. Step four, spawning and hatching of fertilized eggs: the successfully mated female prawns are transferred to a spawning tank for spawning, with a female prawn density of 4-6 per m 2 The seawater in the spawning tank is strictly filtered and kept in a slightly aerated state, and the density of the fertilized eggs is not more than 500,000 per m 3 The female prawns after spawning are fished out and returned to the original culture tank.

2. The method for improving the mating rate of P. vannamei according to claim 1, wherein: In step one, the benthic diatom liquid is observed under a microscope to determine whether it is a beneficial algae such as diatoms, cycloids, nautiloids, or oval algae; otherwise, the benthic diatom liquid is collected again.

3. The method for improving the mating rate of P. vannamei according to claim 1, wherein: In step three, the female shrimp are removed: mating usually lasts for 3-5 hours; after mating, the spermatophores of the male shrimp can be observed adhering to the spermatheca between the 3rd and 4th pairs of walking legs on the thorax of the female shrimp. The female shrimp that have successfully mated are returned to the female shrimp breeding pond for further cultivation, and can continue to mate when they reach sexual maturity.

4. The method for improving the mating rate of Litopenaeus vannamei according to claim 1, characterized in that: In the second step, the female and male parent shrimps are fed in separate tanks, the dissolved oxygen is kept above 5 mg / L, the seawater specific gravity is 1.016-1.025, the pH value is 8.0-8.5, the water temperature is 25-28℃, and the cultivation density is 10-15 tail / m 2 . 2 ; (2) Feeding and nutritional fortification: During the fortified cultivation process, the daily feed amount is 7%-15% of the shrimp's body weight; artificial maturation is carried out after 18-20 days; (3) Artificial ripening: Gradually increase the water temperature in the rearing pond, with a daily increase of no more than 0.5℃, and maintain a constant temperature when it reaches 27-30℃. Use the scalding method to scald one side of the eyestalk of the female shrimp.

5. The method for improving the mating rate of P. vannamei according to claim 4, wherein: In step two, sandworms, bloodworms, oysters, and squid are used as feed for nutritionally fortified breeding.