Animal performance and welfare of giant freshwater prawn (Macrobrachium rosenbergii) subjected to feed restriction

ABSTRACT Behavior activities of giant freshwater prawn Macrobrachium rosenbergii juvenile, their performance, and acquired lesions when under temporary feed restrictions were analyzed. Five animals/experimental units (10 prawns/m2) were employed for treatments DFL – daily feed supply in the light phase; DFD – daily feed supply in the dark phase; AFL – alternating feed supply in the light phase; and AFD – alternating feed supply in the dark phase, for a 24-hour period, with four replications each. Prawns were fed a pellet diet, twice a day, with 10% of their biomass/day. Specimens were monitored during 60 consecutive days, with behavior recording daily and weighed every 10 days, with assessment of lesions and/or amputated limbs at the end of the experimental period. Types of behavior comprised exploring, grooming, inactivity, crawling, swimming, excavation, burrowing, agonism, and feed ingestion by scan sampling, with instantaneous registration every 60 s, in 15-min windows, before and after feed, in light and dark phases. Feed restricted in alternate days during light and dark phases did not interfere in growth or survival of the specimens, with increase in apparent feed intake and less feed conversion ratio and specific growth rate. Agonistic behavior was higher in specimens with feed restrictions, with an increase in the number of lesions and amputations. The above demonstrates welfare decrease in farmed M. rosenbergii and depreciation in the quality of the final product.