The Effects Of Feeding Frequency And Feeding Level On Growth Performance And Physiological Function Of Juvenile Gift, Oreochromis Niloticus

The present experiment investigated the effects of feeding frequency and feeding level on growth performance and physiological function of juvenile GIFT. A factorial experiment was carried out in ten concrete ponds, with two feeding frequencies (2and3meals/day) and five feeding levels (2,4,6,8and10%body weight per day-BW/day), there were3replicates per group with60tilapias and the tilapias with an average initial body weight of (0.84±0.01) g, over a period of70days. The following results had been:1. The growth of Tilapia:feeding level significantly affected the growth index (P<0.05).When feeding with2%BW/day, the tilapias were hungry chronically and had no growth basically for the final body weight less than3g. Based on the weekly growth parameters of juvenile GIFT, feeding with2and3meals/day had no significant influence on growth parameters of juvenile GIFT, but the best feeding level was respectively10%,8%and6%BW/day when the weight gain of fish was respectively less than1g,1to5g and5to16g.2. The nutrition composition of Tilapia:feeding level significantly affected the nutrition composition (P<0.05). Fish that received8%and10%BW/day, presented significantly higher crude fat content when compared to fish fed with2%,4%and6%BW/day (P<0.05).3. The HSI and amount of fat in liver and muscle of Tilapia:Feeding frequency and feeding level had extremely significant influence on HSI and the amount of fat in liver (P<0.01). When feeding frequency was constant, the HSI and amount of fat in liver and muscle of the juvenile GIFT showed an increasing trend with the feeding level increasing.4. The digestive enzymes of Tilapia:Feeding level significantly affected the digestive enzymes (P<0.05). Fish that received8%and10%BW/day, presented lower activities of digestive enzymes when compared to fish fed other treatments.5. The metabolism enzymes of fat in Tilapia:feeding level significantly affected the metabolism enzymes (P<0.05). Fish that received6%BW/day, presented higher activities of metabolism enzymes of fat when compared to fish fed other treatments. The activities of metabolism enzymes of fat were decreased when the feeding level was too low or too high in the treatment of juvenile GIFT.6. The serum biochemical indexes of Tilapia:feeding level significantly affected the serum biochemical indexes (P<0.05). When feeding frequency was constant, Fish that received8%and10%BW/day, presented a certain degree of liver damage and the activities of ALT, AST, LDH and the content of LDL-C significantly higher than the fish fed with4%and6%BW/day (P<0.05). 7. The immunity of Tilapia:Feeding level had extremely significant influence on T-SOD, MDA, WBC, LYS, ALP and C3(P<0.01). Fish that received8%and10%BW/day, presented a lower immunity when compared to fish fed other treatments. When feeding with6%BW/day, the fish showed a better immune response.8. The histological observe liver of Tilapia:Feeding with2and3meals/day had no significant differences on liver histology of juvenile GIFT. fish that received2%,8%and10%BW/day, appeared a certain degree of fatty liver.