Feasibility of compensatory growth in early juveniles of "red claw" crayfish Cherax quadricarinatus under high density conditions

STUMPF L; LOPEZ GRECO L.S; CÁRDENAS SARMIENTO PN; TIMPANARO S

AQUACULTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019 p. 302 - 310

0044-8486

The aim of this work is to study the feasibility to induce compensatory growth in Cherax quaricarinatus crayfish at an early stage of development under high density, the typical conditions of nursery phase. An advantageous characteristic of this species is the capacity to face temporary starvation, especially at early stages of development. This would help to design feeding strategies avoiding overfeeding, and diminishing operating costs in aquaculture. In this sense during the last 8 years it was analyzed in this species the application of intermittent feeding, known as unfavorable feeding condition followed by daily feeding, named favorable feeding condition. This alternative feeding protocol was used in the present study to trigger compensatory growth. Juveniles weighing 0.07±0.01g were distributed in 2 feeding regimes: DF60 with juveniles fed daily during 60 days and IF20+DF40 with juveniles deprived of food for 4 days, and fed for 4 days in repeated cycles during the first 20 days, and daily fed from day 20 to day 60. Juveniles were stocked in each tank under 97 crayfish/m2 density, and zootechnical and biochemical parameters were evaluated throughout 60 days. A very suitable and similar survival (~ 65%) was maintained between feeding regimes, and the previously unfavorable feeding condition did not promote greater aggression among juveniles. There was a small compensatory response yet no recovery occurred, probably because a long-term favorable feeding condition could have triggered a strong compensatory response, and catch-up to the control size. Hyperphagia and improvement of feed conversion were not observed in juveniles of IF20+DF40 suggesting that the high density was the key. This could have affected the competition for food and changed the priority in allocating energy resources for accelerated growth. Lipids and glycogen content from body mass were strongly depleted after unfavorable feeding condition, but there was almost a 100% recovery during favorable feeding condition. We suggest that this response was detrimental to body mass as a priority and as a strategy for juveniles to extend survival during the ?double? nutritional stress caused by food restriction and high density. The applicability of this alternative feeding strategy during an intensive production system can be viable. However, some changes must be considered in order to trigger compensatory growth.