بررسي كارآيي غذاده تقاضايي با مكانيسم جديد N.D.F در غذادهي ماهي قزل آلا

The use of New Demand Feeder (N.D.F) in rainbow trout (Oncorhynchus my kiss) production

The aim of the present paper is to evaluate the use of new demand feeder in rainbow trout production. The new feeder can be adjusted according to the pellet size, food fall amount and fish power. Moreover, pendulum strength is adjustable based on fish size and their number. This system relies on the fact that the fish control the amount of food based on their appetite. This research has focused on characterizing: (1) how self-feeding activity is related to food demand; and (2) how self- service food supply is related to growth, and itʹs compared with hand feeding. For the feeding system to function correctly, rainbow trout must first leam how to operate it. Results showed that Trout reared in raceways in group of 1000 individuals with equal weight, require about 15 days to learn how to apply the system and to reach a stable level of self-feeding. For 12 weeks, weight and length of the fish were measured every 14 days. According to the results, the growth of fish in treatment ponds was more than the growth of fish in control ponds and had a significant difference (P<0.05). Oxygen amount was higher in treatment ponds. Algae growth in the control ponds was more than treatments ponds. Results showed that this apparatus can be used in windy and wavy conditions because of its adjustable pendulum strength.