Discussion on the multiple times of home fish
When my field was artificially breeding home fish in 1991, we first changed the traditional mode of production of the broodstock to broodstock. We produced quarantine for each mature broodstock three times at different times, and then performed the same test on the bream and broodstock. These two kinds of fish can also Three times a year, except that quail and squid are affected by the feeding of nutrients required for gonadal development in food-water organisms due to their filter-feeding species, the growth rate of fertility is affected by the development of water quality, but at least they can be produced twice a year. The normal spawning rate, fertility rate, and emergence rate of the three species of fish were all the same as usual, and their total egg production (including spawning of quail and squid twice a year) reached 300,000 grains. / kg, which is about three times more than the traditional total egg production of 100,000 tablets/kg. This has a very practical and positive significance for the supply shortage of domestic fish in the 1990s. Of course, the innovation of this technology has certain controversy on the theoretical and scientific research of the aquatic academia.
According to the study of fish breeding related disciplines and conventional production, sexually mature broodstock fish only produce one egg per year in the entire production situation, and the amount of eggs laid (that is, total egg production) is generally 100,000 capsules/kg. Occasionally, there was a second oxytocin production in specific circumstances, but its total egg production remained unchanged. The theoretical basis is that: the family fish is a spawning type of fish, a one-year sexual cycle, when the ovarian gonadal is in the fourth (IV) period, the transition to the fifth (V) stage egg by exogenous hormones and ecological stimuli Granules are then eliminated from the body and the simultaneously developed eggs are generally produced. Afterwards, the ovaries wait for the next sex cycle to go through the degenerative absorption process from the sixth (VI) period to the third (III) period. Redevelopment. The rare second oxytocin production is due to a variety of physiological and ecological factors, incoordination of ovarian development, ovulation and spawning activities are not synchronized, resulting in some (or all) of the eggs can not produce semi-producing (or dystocia) It takes some time before the oxytocin is produced and the unproduced ovum is re-output. However, this is only a repetition of spawning activities. The amount of egg production does not increase, which means that this second oxytocin production is In the specific case that the eggs were not produced at the first production, the sum of the two egg productions does not exceed the number of eggs produced at one time in the whole production.
Here's a brief introduction to the numerous technologies of the year:
The broodstock individuals are generally: 4-12 kilograms of grass carp, 2-5 kilograms of carp, and 5-10 kilograms of carp. The broodstock area is 0.5-2 mu. The broodstock is mixed and bred. The grass carp is mainly used for rearing carp. The proportion of grass carp is roughly equal to: weight (%) ratio 75:20:5 and mantissa (%) ratio 57. :40:3. Feeding mainly fodder, no fertilizer, fine material generally do not feed, 200-300 kilograms of acre stocking, water depth of about 1 meter, from time to time to add new water, oxytocin according to its instructions for injection of the same dose each time, urine production temperature At 17-33°C, production time is from early April to late July, and production is sometimes delayed until August according to market demand. According to our production practice for more than ten years, there are two issues that are still worth paying attention: one is that the second and third time (in the case of the first full production) each egg production is higher than the first time (such as grass carp About 80,000-100,000 tablets/kg at a time, and about 10-15 million tablets/kg in the second and third.) The second is that if there is no production (half-production) or no production after the first oxytocin production, the subsequent oxytocin production effect is not good, and sometimes there may even be the phenomenon that no eggs can be produced all year round.
For the family fish is a spawning type or a multiple spawning type, a comprehensive view of aquatic monographs is mostly defined as the former, even if some people think that may be multiple spawning types, there is no conclusion. In combination with our multiple spawning types of reproductive production, our thinking analysis is whether or not the physiology of gonads has undergone a series of stress changes and produced a certain qualitative change due to long-term artificial breeding of the fish. And quantitative change, that is to say with a certain evolution and change, from the original spawning type to multiple spawning types, the sexual cycle changes from one anniversary to alternate within a short time (about 30 days), or The development of the egg phase is multipolar (coexisting at multiple phases) rather than synchronous development, and the amount of egg flies also increases. Therefore, this raises a new question for related disciplines: whether the sexual cycle of gonadal development in domestic fish needs to be redefined, and whether the overproducing egg lays a foundation for the development of egg tissue in a short period of time and whether the entire fish reproduction physiology should be For further discussion, hope that the fisheries colleagues have given us corrections and on-the-spot investigations.
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