Breeding technique of bullfrog

Abstract: bullfrog belongs to amphibia, Anura, frog family, frog genus. Bullfrog breeding is a new special economic breeding industry at home and abroad. Bullfrog is a kind of amphibian with the highest economic comprehensive utilization value. it originated in North America and was introduced into China in 59. It gets its name because it sounds like a cow. It is a large edible frog. Bullfrog has fast growth, delicious meat, rich nutrition and high protein content.

Bullfrog belongs to amphibian class, Anura, frog family, frog genus. Bullfrog breeding is a new special economic breeding industry at home and abroad. Bullfrog is a kind of amphibian with the highest economic comprehensive utilization value. it originated in North America and was introduced into China in 59. It gets its name because it sounds like a cow. It is a large edible frog. Bullfrog is a delicacy on festive banquets because of its fast growth, delicious meat, rich nutrition and high protein content.

The economic value of bullfrog

1. Eat. Bullfrog is regarded as a delicacy of state banquet in our country. When US President Ronald Reagan visited China in 1984, President Li Xiannian entertained nine dishes at the banquet, and Reagan praised the "stone scale legs" made of bullfrogs. Today, bullfrog has been listed in the recipes of many hotels and restaurants in our country. Eating bullfrogs is not uncommon in the world. The world's edible bullfrog originated in France. It was later introduced into the countries of North America. At present, the annual consumption of bullfrogs in the international market is more than 300000 tons, with a price of about US $50 per kilogram. China began to raise it in 1986 and produced 300 tons last year. Jiangsu, Zhejiang, Hainan, Shanghai, Guangdong and Shandong are potential markets. The bullfrog is sold to the coastal hotel for 30muri 60 yuan / kg.

2. For medicinal use. The frog meat is flat, tastes sweet, and the gallbladder is cold. It has the effect of promoting blood circulation and eliminating accumulation, relieving heat and detoxification, tonifying deficiency and relieving cough to treat a variety of diseases, such as edema, throat erosion and so on.

3. Leather. The leather of bullfrog is thick, soft, smooth, elastic and has colorful patterns, which can be used as a good raw material for leather products such as wallets and gloves. Shoes made of frog skin cost 400 yuan a pair. Frog skin is extracted and processed into leather glue, which is used as an adhesive for jewelry, diamonds and other ornaments.

4. Feed. Feeding chickens with mixed feed made from the by-products of bullfrog (head and viscera) can increase the laying rate.

5. An expert at catching insects. Bullfrogs, like other frogs, feed on agricultural pests. On average, a bullfrog can prey on more than 10,000 pests a year. A tadpole eats at most more than 100 wigglers a day. Using bullfrog to control pests can not only effectively control harmful insects and reduce the harm to crops, but also greatly reduce the amount of pesticides.

6. For aerospace use. Frog oil is used in the aerospace industry.

Life habits

① is amphibious in rivers, ponds, swamps and grassy banks. ② gregarious. ③ metamorphosis. ④ kills each other. ⑤ thermotropism. ⑥ hibernates. ⑦ body color variability: skin color can change with temperature, light and hue of the living environment. There are generally two basic colors: one is dark brown, the other is green. It is dark brown in winter and early spring, bright green in late spring and light brown in autumn. The baby frog is green. ⑧ call: the bullfrog sounds like a scalper. When the breeding season comes, the song changes. ⑨ regeneration: bullfrog can grow again after part of its body is damaged, shedding or amputated. ⑩ lifespan: bullfrog has a long life span and can normally live up to 16 years.

Breeding techniques of bullfrog

Bullfrog is a hermaphrodite. During reproduction, mature individuals enter the water to "grab the right". Female ovulation and male ovulation are combined in water for in vitro fertilization, which is a typical representative of frog reproduction.

1. The age of sexual maturity. The gonadal development of bullfrog generally takes about 9 months from hatching tadpoles to sexual maturity. In terms of body weight, the female frog is more than 350g and the male frog is more than 300g. But in fact, the sexual maturity of bullfrogs varies greatly due to different temperature, bait and breeding methods.

2. Male-to-female ratio: 2Rd 3pm 1R 1

3. Stocking density: 5 pairs / 10 years.

4. Spawning site: Song10mur20, Hang1.2m, prevent from going out of the wall and net, about 1m, half of the water surface and half of the land, and some herbs should be planted on land and water.

5. Spawning habits

① estrus behavior: both sexually mature male and female bullfrogs have obvious estrus behavior under the influence of external environmental factors such as temperature, light, etc. The initial behavior of male oestrus is to constantly call, summon female frogs, averaging more than 100 calls per hour, and chase behavior. Grab the female frog, gently touch her lower jaw chest, and the left and right forelimbs will quickly close and hold. It can be seen that the marriage tumor on the medial base of the first limb of the forelimb is particularly obvious and fleshy red. The female frog in estrus does not eat food and jumps to the sound of the male frog, sometimes making a "click" to respond, indicating that the female frog has a courtship request, and only then does the female frog let the male frog jump on his back and hug each other.

② hug pair: when the best part of estrus is reached, the male and female hug each other, usually in the second half of the night, and the hugging time is generally as long as 1 Mel for 2 days.

③ spawning and fertilization: bullfrog breeding season is from April to September, sooner or later depending on the region. The external conditions for spawning are not high, and the key is temperature. As long as the water temperature reaches 20 ℃ and 30 min, both ponds and ditches can lay smoothly. The ideal environment requires quiet, leeward, few pedestrians and aquatic plants on the shore. When the cuddling behavior is near the end, the female frog is stimulated by allogeneic stimulation, which is transmitted to the central nervous system through the sensory organs, and then to the pituitary gland, which promotes the pituitary gland to secrete hormones. Under the action of sex hormones, the female frogs stare hard, the abdomen shrinks with the help of breathing and male frog cuddling, and the eggs are produced in vitro. At the same time, the male frog excreted semen and fertilized in vitro. The time of ovulation is 10ml / 20min. The average individual lays 20-30, 000 eggs, up to 50, 000 eggs.

Bullfrog eggs are round, divided into two poles, animals are extremely black, plants are grayish white. The newly laid eggs have animals at the top and some plants at the top, so the eggs just laid are black and white. It's a little numb. About 60 minutes after spawning, the animals are all facing up, which is called the automatic transposition of the eggs. If there are white plant polar eggs after 2 hours, they are unfertilized eggs. Based on this, the fertilization rate of bullfrog after spawning can be calculated, and the fertilization rate is generally more than 90%.

There are many reasons for oviposition and non-fertilization, mainly because ① has an imbalance in the female-to-male ratio. The normal female-to-male ratio is 1:1, the fertilization rate is more than 90%, and when the fertilization rate is 75% 80% at 2: 1, the fertilization rate is only 40% at 3: 1. Too many or too few males affect it. ② male frog is too old, weak and disabled. The practice shows that the fertilization rate of the two-year-old frog is the highest, and the fertilization rate of the breed frog that gives birth to 4 births is lower. The water temperature of ③ is too low and the water quality is not clean. The water surface is too wide and the spawning place is not suitable. There are also many ways to improve the fertilization rate. Artificial insemination is an effective shortcut, and the fertilization rate can reach 90%.