Compositions, and some Haematological Parameters in Caspian salmon (Salmo trutta caspius)

The present study was aimed to evaluate the effect of different levels of choline chloride (ziro, 250, 500, 750, 1000, and 2000mg/kg food) on the growth performance, carcass compositions, and haematology of Caspian salmon (Salmo trutta caspius).

270 fish pieces weighing 8.82±0.38 in 18, 250‐liter fiberglass tanks (15 fish per tank) with 3 repetitions per treatment with one of six experimental diets (control diet, Cho250, Cho500, Cho750, Cho1000, and Cho2000) were fed for 10 weeks.

Final weight, weight gain, specific growth rate index, protein yield ratio, obesity ratio, and feed conversion ratio of fish fed with diet containing appropriate levels of choline (750 to 1000mg/kg choline), were significantly higher than the fish fed with control diet and Cho250 diet (p≤0.05). There was a significant decrease in the feed conversion ratio of Cho750 and Cho1000 treatments compared to control treatment. It can be acknowledged that the Caspian Sea salmon cannot meet the physiological needs of choline by biosynthesizing choline from the liver or methionine. By increasing choline in the diet, the amount of protein and fat in the carcass increased significantly, but the moisture content of the carcass decreased (p≤0.05). Also, moderate amounts of fatty liver fish fed with control treatment and Cho250 treatment were significantly lower than other treatments. The results showed a negative relationship between the increase in choline levels and the activity of hepatic blood enzymes (p≤0.05).

In order to increase the growth process, strengthen the immune system, and optimally combine the carcass, the most appropriate amount of choline chloride is 750‐1000mg/kg in the diet of Caspian Sea salmon.