Rainbow trout is known for its striking brown-red vertical patterns along the lateral line, which inspired its name. This fish is highly valued for its delicious taste, rich nutritional content, and minimal bones, making it a popular choice for aquaculture. Due to its easy breeding and high economic value, it has been recognized by the United Nations Food and Agriculture Organization as one of the top four freshwater species for promotion. It is now considered a premium fish in many regions. Practical experience has shown that raising rainbow trout in flowing water can yield 3-5 million kilograms per acre annually, offering significant economic returns. As a result, many areas have started to actively develop artificial breeding programs. Regions such as Huairou in Beijing, Gansu, and Fujian have successfully implemented large-scale farming. Rainbow trout is a cold-water species that thrives in temperatures between 1°C and 24°C, with the ideal range being 14°C to 16°C. It requires water with at least 5 mg/L of dissolved oxygen and a pH level between 7 and 8. Fish farms can be established wherever these conditions are met. It can be raised in ponds, groundwater, reservoirs, or natural cold springs. The site should have a slight slope for efficient drainage and natural aeration. Each pond should be 100-200 square meters, made of cement, rectangular in shape, and designed to allow even water flow for optimal growth. If possible, building ponds on hillsides is even more advantageous. Artificial breeding of rainbow trout typically begins when the broodstock reaches 2-3 years of age. They spawn once a year, producing between 1,000 to 3,000 eggs each time. Spawning usually starts in December each year. For breeding, the broodstock requires a gravel-bottomed tank with a depth of 1.5 meters and a water flow rate of 0.05 cubic meters per second (or 5 liters per second). The stocking density should be 1-3 fish per square meter, with an equal male-to-female ratio of 1:1. Rainbow trout is sensitive to light, so the lighting should not exceed 12 hours daily. During the breeding season, the feed composition changes—20-30% of the total feed is replaced with animal-based feed during gonadal development, increasing to 50-60% before and after egg collection. The feeding amount should be 0.5% to 2.0% of the fish's body weight. When females are ready to spawn, they dig nests in shallow, slow-moving water with darkened bodies, red vents, and swollen, soft bellies. When the eggs are mature, they will begin to ooze out when gently pressed. Males, on the other hand, have darker coloration, rougher skin, and soft excretory openings. Sperm can be seen when the abdomen is lightly pressed. Egg collection usually begins when the water temperature is between 1°C and 11°C, with the best period being 5°C to 9°C. The extraction method involves holding the female head-up and pressing her belly toward the vent to release the eggs into a basin. The same process is repeated for the male, and his sperm is added to the basin. The mixture is stirred with a feather for 30 seconds, then left to sit for 2 minutes before adding more fresh water and letting it rest for 4 hours. The fertilized eggs are then placed in a hatching tray under shaded conditions. For incubation, a wooden, cement, or plastic tank measuring 200x40x37 cm is used. Hatching trays of 33x33x1.6 cm are stacked in a sink. A cover plate is placed on top to prevent drifting. The hatchery should be shaded. The ideal water temperature for incubation is between 7°C and 13°C, with the best range being 8°C to 10°C. The water flow rate should be 10-20 liters per minute. Throughout the incubation period, any dead eggs should be removed promptly. Weekly sterilization with 1% formalin or 2% saline for 30 minutes helps improve hatching success. This information was originally published in the "Hubei Science and Technology News" on December 17, 2002.

API

what is API?

High-purity plant monomer refers to one or more single chemical components with specific biological activity or pharmacological effects extracted from plants, and its purity is usually high, meaning that the content of the component in the extract reaches a certain percentage, and the content of other impurities or irrelevant components is low.

These plant monomers are usually secondary metabolites of plants, such as flavonoids (flavonoids), alkaloids (alkaloids), terpenoids (terpenoids), phenolics (phenolics), etc., which play a variety of physiological functions in plants such as defense, signal transduction, and antioxidant. Due to their pharmacological activity, high-purity plant monomers are often used in pharmaceuticals, health products, cosmetics and other biotechnology products.

For example, Naringenin is a high-purity plant monomer extracted from citrus plants with antioxidant and anti-inflammatory activities; Corosolic acid is a high-purity active monomer extracted from loquat leaves, which is considered to be effective in treating type 2 diabetes and obesity.

Extraction and preparation of high-purity plant monomers usually require a complex separation and purification process, including extraction, column chromatography, crystallization, recrystallization and other steps to ensure the purity and activity of the final product. These processes may be required by specialized biotechnology companies.

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