Study On Partial Replacement For Fish Meal With Maggot Meal In Feed For Rice Field Eel (Monopterus Albus)

Tow experiments were conducted to evaluate the possibility of housefly larvae as one kind of feedstuff for Monopterus ablbus commercial feed.1. Experiments were conducted to investigate the influence of feeding frequency on feeding rate, specific growth rate, food efficiency, growth variation and body composition in a native fish, Monopterus albus. Five groups of the juveniles were fed to satiation including: two meals per day, three meals per day, four meals per day, twelve meals per day and twenty-four meals per day for 30 days. The results showed that:the feeding rate and special growth rate increased significantly at four meals per day (P<0.05); and the fish fed with four meals per day showed higher food efficiency than the fish fed with two meals per day (P<0.05); but the rests were not significantly different with each othe. With the gradually increasing of feeding frequency, individual differences of fish bodyweight dwindled down, fish size became more equirotal, as feeding frequency increasing, body composition were not significantly different with each other. Therefore it indicated that the growth performance was affected by feeding frequency, and feeding 4 times daily was the optimum.2. A 60-day trial was conducted to evaluate the potential of replacing fish meal with maggot meal in experimental diets for ricefield eel in Aquarium (80 cm×40 cm×45 cm). Five isonitrogenous diets were formulated with fish meal replaced by maggot meal at the levels of 0 (39.82% fishmeal),25%,50%,75%and 100%, respectively. The maximal specific growth rate, feed conversion ratio and weight gain were observed in the ricefield eel fed the diet containing 50% maggot meal (P<0.05). Crude protein in ricefield eel fed the diet containing 50% maggot meal was no significantly than that in the ricefield eel fed the control diet, and crude fat, crude ash and moisture showed significant difference among the other treatments. When M. albus feed on diets with different content of maggot meal, the activities of digestive enzymes in stomach, foregut, hindgut and liver of M. albus are descended, when 50% of replacement of maggot meal to the diets, the activity of protease was no significantly than that of control group; When maggot meal protein had replaced fish meal by25%, the activity of trypase was no significantly than the control group; When maggot meal protein had replaced fish meal by25%, the activity of lipase in the stomach and liver of M.albus was no significantly than that of control group,but the replacement more than 25%, the activity of lipase in M. albus was significantly lower than that of control group(P<0.05); When maggot meal protein had replaced fish meal low than 50%,maggot meal protein had no significant influence on lipase in liver,stomach and intestinal tract of M. albus; When maggot meal protein had replaced fish meal low than 50%,maggot meal protein had no significant influence on amylase in liver,stomach and intestinal tract of M. albus, but when the replacement more than 50%, the activity of amylase in M. albus was significantly lower than that of control group(P<0.05), when the replacement of maggot meal by 25%, the activity of amylase in M. albus was higher. When maggot meal protein had replaced fish meal by50%, the activity of serum T-SOD of M. albus was significantly than that of control group, the replacement by25%, the activity of serum LZ in M. albus was no significantly than that of control group; the replacement by ever group, the activity of serum SGPT in M. albus was no significantly. When maggot meal protein had replaced fish meal by50%, the phagocytic activity of leukocytes in M. albus was significantly than that of control group(P<0.05); The results showed that adding maggot meal with a ratio of 50% into the diets can enhance the nonspecific immunity of ricefield eel and improve their liver function to some degrees.It can be suggested from the experiment that it is better to add fish meal into the maggot meal for the ricefield eel diets, even though 25%-50% fish meal can be replaced by maggot meal in the ricefield eel diet.