Effects of omnivorous fish feed on enzymatic activity and metabolic profile of South American crustaceans: potential organic extractive species of fish farming

MUSIN G.; CALVO N.S.; MORA C.; DE BONIS C. J; COLLINS P. A.; CARVALHO D. A.

Shangai

Congreso; Global Conference on Aquaculture 2020; 2021

FAO

One way to develop more sustainable aquaculture systems is through species diversification and optimization of the feed input, such as that obtained by integrated multitrophic aquaculture (IMTA). Macrobrachium borellii (Palaemonidae) and Aegla uruguayana (Aeglidae) are freshwater crustaceans native to South America that have many useful features to be implemented in an IMTA. The effect of a commercial feed formulated for omnivorous fishes on growth, digestive enzyme activity, and metabolic profile was analysed to gather information about nutritional requirements of the species. Forty-five adults of each species were captured in the wild, weighed, measured and placed in glass aquariums (density: 62,5 individuals/m2). Crustaceans were fed twice a day ad libitum with omnivorous fish feed (PA-27, Garay-SRL, Argentina). The experiment was carried out for 40 days. When it finished, crustaceans were weighed, measured and sacrificed. Hepatopancreas and muscle tissues were extracted and immediately ultra-freezed for posterior analyses of digestive enzymes and metabolite profile. Growth increments of organisms were calculated. Enzymatic activities of lipase, total proteinase and amylase were determined by adjusting established protocols. Glycogen, triglycerides and protein were measured in hepatopancreas and muscle following established procedures. A. uruguayana registered higher growth (21.13+6.18%) than M. borellii (-7.05+11.51%) and also higher enzymatic activity, with lipase activity standing out significantly (282.37+18.58U/mg.prot vs. 121.54+60.05U/mg.prot) (F=10.44; p=0.0112). The amounts of glycogen and triglycerides recorded in hepatopancreas of aeglids were also significantly higher (20.44+9.43µmol/g and 70.39+14.26µmol/g, respectively) than those of prawns. Under the experiment conditions aeglids had better performance than prawns in terms of growth and energy reserves. This result leads to consider A. uruguayana as a potential species for IMTA with omnivorous fishes.