there are 51 types of salmon fish.
there are 51 types of salmon fish.
how many types of salmon fish are there?
51
Na
Na
the issue of feeds in fish farming has been a controversial one. many cultured fishes (tilapia, carp, catfish, many others) require no meat or fish products in their diets. top-level carnivores (most salmon species) depend on fish feed of which a portion is usually derived from wild-caught fish (anchovies, menhaden, etc.). vegetable-derived proteins have successfully replaced fish meal in feeds for carnivorous fishes, but vegetable-derived oils have not successfully been incorporated into the diets of carnivores. research is underway to try to change this, such that even salmon and other carnivores could be successfully fed with vegetable products. the f3 challenge (fish-free feed challenge), as explained by a report from "wired" in february 2017, "is a race to sell 100,000 metric tons of fish food, without the fish. earlier this month, start-ups from places like pakistan, china, and belgium joined their american competition at the google headquarters in mountain view, california, showing off feed made from seaweed extracts, yeast, and algae grown in bioreactors." not only do the feeds for carnivorous fish, like certain salmon species, remain controversial due to the containment of wild caught fish like anchovies, but they are not helping the health of the fish, as is the case in norway. between 2003 and 2007, aldrin et al., examined three infectious diseases in norwegian salmon fish farms--heart and skeletal muscle inflammation, pancreas disease, and infectious salmon anemia. in 2014, martinez-rubio et al., conducted a study in which cardiomyopathy syndrome (cms), a severe cardiac disease in atlantic salmon ("salmo salar"), was investigated pertaining the effects of functional feeds with reduced lipid content and increased eicosapentaenoic acid levels in controlling cms in salmon after infection with piscine myocarditis virus (pmcv). functional feeds are defined as high-quality feeds that  beyond purposes of nutrition, they are formulated with health promoting features that could be beneficial in supporting disease resistance, such as cms. in choosing a clinical nutrition approach using functional feeds could, potentially move away from chemotherapeutic and antibiotic treatments, which could lower the costs of disease treatment and management in fish farms. in this investigation three fishmeal-based diets were served--one made of 31% lipid and the other two made of 18% lipid (one contained fishmeal and the other krill meal. results demonstrated a significant difference in the immune and inflammatory responses and pathology in heart tissue as the fish were infected with pmcv. fish fed with functional feeds with low lipid content demonstrated milder and delayed inflammatory response and therefore, less severe heart lesions at earlier and later stages after have pmcv infection.
fish farming