| Tenebrio molitor is a high-quality insect protein resource with high protein and fat content.It has a complete range of amino acids and fatty acids with a reasonable proportion.In addition,it also contains a variety of functional active substances.However,the application research of mealworm in the aquafeed industry is rarely reported.Based on this,Spinibarbus sinensis and Andrias davidianus were chosed as the test subjects for the following two aspects of researches:1.Effect of mealworm on growth performance,muscle quality,antioxidant and blood indices for Spinibarbus sinensis.In this experiment,180 fishes with an initial body weight of(21.9±1.92)g were selected and randomly divided into 3 groups.Each group was divided into 3 replicates of20 fishes per tank.3 groups were respectively fed controlled diet containing 18%fish meal(fish meal group),experimental diet that replaced the fish meal with 50%mealworms(substitution group)and fresh mealworm(mealworm group)for 60 days.The results showed that:(1)The final mean weight(FBW),weight gain rate(WGR)and specific growth rate(SGR)of the substitution group and the mealworm group were significantly higher than the fish meal group(P<0.05).The food intake(FI),protein intake(PI)and fat intake of substitution group were significantly higher than fish meal group(P<0.05),the FI and feed coefficient rate(FCR)of the mealworm group were significantly lower than the fish meal group(P<0.05).(2)The visceral index of substitution group and mealworm group was respectively increased by 8.64%and 26.46%compared with the fish meal group(P<0.05).(3)The crude fat content in the muscles of substitution group and mealworm group was significantly higher than fish meal group(P<0.05).(4)The content of essential amino acids(∑EAA),flavour amino acids(∑DAA)and total amino acids(∑AA)in substitution group mealworm group were significantly lower than the fish meal group(P<0.05).(5)The hardness and chewing index of the muscles in substitution group were significantly lower than fish meal group(P<0.05),and the recovery was significantly higher than fish meal group(P<0.05).The muscle recovery and chewing index of mealworm group was significantly higher than that of the fish meal group(P<0.05).(6)The total cholesterol(TC)in substitution group and mealworm group were significantly lower than those in fish meal group(P<0.05).Compared with fish meal group,the alkaline phosphatase(ALP)activity in substitution group and mealworm group respectively increased by 13.42%and 144.67%(P<0.05),while the alanine aminotransferase and aspartate aminotransferase increased significantly(P<0.05).(7)The superoxide dismutase(SOD)activity in the liver and muscles of substitution group were significantly lower than that in fish meal group(P<0.05),and the activity of SOD in the liver and muscular SOD,total antioxidant capacity(T-AOC)and glutathione peroxidase(GSH-PX)in mealworm group was significantly lower than fish meal group(P<0.05).In summary,whether the use of mealworm instead of 50%of fishmeal or feeding fresh mealworms can improve the growth performance,increase fat intake and muscle fat content,improve muscle texture quality,but it also increases the visceral index,the total amount of amino acids and balance of muscles are reduced,and it also has an adverse effect on the liver’s health level and the body’s antioxidant function.2.Effect of mealworm on growth performance,muscle momposition,the ability of digestion,antioxidation and immunity for Andrias davidianus.In this experiment,72 giant salamanders with an initial body weight of(29.9±0.42)g were selected and randomly divided into 3 groups.Each group was divided into 3replicates 8 giant salamanders per tank.3 groups were respectively fed fresh fish(fish meat group),experimental artificial diet containing 15%dry mealworm(artificial feed group)and fresh mealworm(mealworm group)for 80 days.The results showed that:(1)Compared with fish meat group,the WGR,PI and fat intake of artificial feed group were significantly decreased(P<0.05),and FI of artificial feed group were significantly increased(P<0.05).The FBW,WGR and SGR of mealworm group were significantly lower than fish meat group(P<0.05).The FCR of artificial feed group and mealworm group was respectively increased by 63.89%and 52.78%(P<0.05).(2)Compared with fish meat group,the visceral index and liver index in artificial feed group and mealworm group were all significantly increased(P<0.05),while there was no significant difference in the fullness,length-to-height ratio,and gut length ratio among the three groups(P>0.05).(3)Compared with fish meat group,the crude fat content in artificial feed group and mealworm group respectively increased by 25%and 45.83%(P<0.05).The muscle collagen content in feed group was significantly higher than fish meat group(P<0.05).(4)The∑EAA、∑DAA and∑AA in artificial feed group were significantly higher than those in fish meat group(P<0.05).The∑EAA and∑DAA in muscle of mealworm group were similar to those of fish meat group(P>0.05).(5)The intestinal lipase,Na~+-K~+-ATPase,and gastric amylase were in artificial feed group significantly lower than in fish meat group(P<0.05);The activities of gastric Na~+-K~+-ATPase was significantly lower in the mealworm group than that in the fish group(P<0.05).(6)There were no significant difference in the number and height of the foregut villi among the three groups(P>0.05).(7)The activities of gastric SOD and intestinal catalase(CAT)in artificial feed group were significantly higher than those in fish meat group(P<0.05),and the gastric CAT activity was significantly increased in mealworm group(P<0.05),but the content of malondialdehyde in the liver and intestine of artificial feed group and mealworm group was significantly decreased(P<0.05).(8)Compared with fish meat group,the gastric immunoglobulin IgM content of artificial feed group and mealworm group respectively decreased by 10.47%and 6.44%(P<0.05),and the ALP activity in the spleen respectively decreased by 40.34%and 21.85%(P<0.05).In summary,compared with feeding fish meat,feeding artificial feed containing mealworm can increase the food intake and muscle fat content of Andrias davidianus,improve the amino acid composition of muscles,promote the development of intestinal villi,and improve the antioxidant capacity of the body;feeding mealworms can increase the muscle fat content and antioxidant capacity of the body of Andrias davidianus;However,feeding artificial feed containing mealworm and fresh mealworm will reduce the growth performance and digestive enzyme activity of Andrias davidianus,increase the visceral index,and also have an negative effect on immunity. |
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