Behavioral Test Of Fat Taste And The Cloning, Expression Of Fat Taste Recepter In Fish

Taste of animal is the final step in the chemical experience for the behavior to accept or reject the food, which is very important for intake of the safe food and the nutrient needs in animals. Traditionally, Five basic taste modalities, such as: sweet, sour, bitter, salty and umami have so far been identified. It has shown that people could be able to perceive the sour, sweet, bitter, salty, umami,which is the result of the existence of the five taste receptors (taste receptor, TR) in the taste buds. Recent compelling evidence from rodent and human studies raise the possibility for an additional sixth taste modality devoted to the perception of lipids. It has been shown that zebrafish can perceive amino acids, bitter tastant as taste stimulants, and what about fat taste? Until now, it has not been reported yet. Based on this, we intend to detect the existence of the fat taste in fishes through behavioral experiments. If present, we intend to further try to identify the candidates fish fat taste receptor.Since fish live in water, it brings much difficulties in conducting fish taste behavioral experiments. we conduct a series of behavioral experiments to detect the taste in zebrefish and blue shark. The subjects were fed food containing a mixture of amino acids and inosine monophosphate, a mixture of Linoleic acid and Arachidonic acid, denatonium benzoateand, and the amounts of ingested food were measured by fluorescence microscopy for quantitatively assaying taste preference–aversion.The results show that: in the early feeding stages of zebrafish,significant ejecting phenomenon are observed when feeding diets containing denatonium benzoate, however, there is no significant ejecting phenomenon when feeding diets containing the other tastants. We further observe fluorescence intensity of gut ingestion food and find that the preferences of the different diets in zebrafish: fatty acids> amino acids> bitter. Statistical analysis of the fluorescence intensities yielded quantitative measurements of food containing Fatty acids and amino acids preference and food containing denatonium benzoate aversion. It seems to prefer diets containing fatty acids.Another behavioral experiments show that: Statistical analysis quantitative measurements of Saccharin, Fatty acids and Amino acids preference and denatonium benzoate aversion in blue shark.The behavior experiments has shown that fish can perceive not only the bitter tastant and Amino acids, but also percecive fatty acids. In addition, our experiment also found that the blue shark has a preference for sweet taste, indicating that fish may have the feeling of sweet taste, which is inconsistent with the report that there is no feeling of sweet taste in zebrafish.CD36 is a kind of lipid adhesion protein expressed in the taste buds of epithelial cells in rats and mice. In recent studies,it has been identified as the receptor of the feelings of fatty acids, in particular to identify long-chain fatty acids (LCFA). We found that CD36 homologous genes also exist in zebrafish via bioinformatics analysis. To explore the expression of CD36, experiments are conduct to check the expression differences in different embryoic stages and different tissues of adult fishes by real time PCR and RT-PCR, respectively. The results show that: CD36 has the highest expression in the intestine; it has the higher expression in the liver, gill and spleen than it in the spine,kidney,brain and bladder relatively in different tissues of adult fishes.CD36 had the highest expression in the blastocyst stage and then gradually reduced until the incubation period in different embryoic stages. These researches are of profound importance in discovering the effects and mechanism of CD36 gene in the taste sense in fish.