Feeding effect of Alternanthera philoxeroides and Elodea nuttallii on crayfish (Procambarus clarkii) growth, hepatopancreas enzyme activity, and muscle quality

In order to clarify the nutritional function of Alternanthera philoxeroides and Elodea nuttallii on crayfish. Under the condition of 50% pellet feeding, the effects of the two aquatic grasses as food sources on the growth and muscle quality of juvenile crayfish were studied, and strategies to improve the material utilization efficiency of the aquaculture system were explored. The results of feeding trial showed that feeding aquatic grasses no significantly affect the survival and body length growth of crayfish, but the body weight in the control group was significantly higher than that in the 50% pellet feeding, E. nuttallii and the A. philoxeroides group (p < 0.05). The muscle weight, hepatopancreatic protease activity, total amino acids, and flavor amino acids of crayfish in the control group were not significantly different from that in the E. nuttallii group, but they were significantly higher (p < 0.05) than that in the A. philoxeroides and the 50% pellet feeding groups. Feeding aquatic grasses significantly improves the hepatopancreas weight and amylase activity of crayfish, but it was significantly detrimental to alkaline phosphatase activity. Muscle fatty acids (C11:0, C13:0, C17:2, C18:1n-12, and C18:3n-3) decreased significantly (p < 0.05) after feeding A. philoxeroides. However, there were no significant changes in total unsaturated fatty acid and total saturated fatty acid content among the groups. Above results suggest that E. nuttallii as an auxiliary feed can promote the growth of crayfish and improve the amino acid composition of muscle in the process of crayfish aquaculture, while the A. philoxeroides has a poor effect on crayfish.