Factors affecting the efficacy of fishery drugs
1. The dosage and dosage form of the drug
The effect of the drug varies with the dose, and even changes qualitatively. For example, when the metal convergence drug zinc sulfate is used locally, the low concentration has the effect of convergence, the medium concentration has the stimulating effect, and the high concentration has the corrosive effect. If the dosage form of the drug is different, even in the case of the same drug dose, the intensity, effect and time of action are also different.
2. Mode of administration
The route of administration, the time of administration, the times of administration and repeated use of drugs can affect the effect of the drug. There is a significant difference in the effect of drugs between external administration routes such as drug bath (or sprinkling) and oral administration (or injection); different administration time (day or night), even if the dose of the drug is the same, the effect will be different.
3. Animal status
The situation and physiological state of aquatic animals are different, which will produce different effects. (1) species differences: there are differences in drug sensitivity among different species, aquatic animals or individuals of the same species; (2) physiological differences: general young and old aquatic animals are more sensitive to drugs; (3) individual differences: different individuals have different drug tolerance, which may be related to individual genetic factors. (4) the function and pathological condition of the body: generally thin, malnourished and aquatic animals under pathological condition are more sensitive to drugs.
4. Environmental factors
For aquatic animals, the environment has a great influence on the effect of drugs. The main influencing factors are: (1) water temperature: the efficacy is generally positively correlated with water temperature, but some drugs are on the contrary, (2) organic matter: it will affect the efficacy of most drugs, such as potassium permanganate, chlorine-containing disinfectants, etc. (3) pH: the effect of acidic drugs, anionic surfactants and tetracyclines and other antimicrobial agents in alkaline water is weakened, while the efficacy of alkaline drugs, sulfonamides and cationic surfactants increases with the increase of pH value. (4) dissolved oxygen: the tolerance of aquatic animals to drugs increases when dissolved oxygen is high, and poisoning occurs easily when dissolved oxygen is low. (5) Light and season: aquatic animals have stronger tolerance to drugs at night than during the day, and are more sensitive to drugs in summer than in winter; (6) the state and resistance of pathogens: some parasites that can form cysts can often form cysts under the stimulation of drugs, and their resistance to drugs is significantly strengthened. in addition, stress factors such as fishing, transportation and water exchange can also increase the sensitivity of aquatic animals to drugs.
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Fish fingerling cultivation in autumn
The range of water temperature in autumn is between 20-30 ℃, which is a good time for fish growth, especially for fish species with small size and poor physique, which is the fattening season, so farmers must strengthen the cultivation of fish species. 1. Disinfect and clear the pond and transfer to the new pond: the old fish pond that breeds the fish species. After several months of feeding in spring and summer, the water quality gradually ages, the dissolved oxygen and food organisms decrease, and the number of pathogenic microorganisms increases, which will stagnate the growth of the fish species. Grass carp are more likely to get sick in such old ponds. At this time, the fish species should be transferred to the new pond to strengthen the cultivation. Where there is a shortage of water
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Pelteobagrus fulvidraco and soft-shelled turtle make a net profit of 10,000 yuan per mu.
In recent years, with the breakthrough of special feed and seedling cultivation technology of Pelteobagrus fulvidraco, various culture models such as main culture, mixed culture and captive culture have been applied rapidly. The "18221" pond efficient culture model is to use Pelteobagrus fulvidraco with high economic value to replace the traditional "four big fish" and soft-shelled turtle mixed culture model. This model means to produce 800 jin of Pelteobagrus fulvidraco and 200 jin of soft-shelled turtle in one mu of water surface, with an output value of 20,000 yuan and a profit of 10,000 yuan. It is a typical high-yield and high-efficiency culture model. Its technical points are as follows: one
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