Time spent in post-feeding activities including feed preference by different weight groups of marron (Cherax cainii, Austin 2002) under laboratory conditions

Abstract

The current study examined time spent on different post-feeding activities and food preference of five weight groups (<15 g, 15−29.9 g, 30−44.9 g, 45−59.9 g and 60−100 g) of marron (Cherax cainii, Austin 2002) fed two formulated feed pellets and frozen copepods under controlled laboratory conditions. The experimental design consisted of housing an individual marron representing a weight group per 20 L glass aquarium. Each weight group was replicated five times, thus using 25 aquaria. All marron were fed with three different food types; fishmeal (FM) and black soldier fly (BSF) (Hermetia illucens) based formulated feed at the rate of 2% of respective body weight and frozen copepods at the rate of approximately 300 individuals per aquarium. Time spent in six selected post-feeding activities was measured in seconds. These activities included resting, walking, searching for food, handling and ingestion of copepods, handling and ingestion of formulated feed, and rejection of food. Results showed that the least amount of time was spent on handling and ingestion of FM by all the weight groups. The handling and ingestion of food in weight group >60 g marron were stopped after half an hour of post-feeding. Where, <15 g and 15−30 g marron spent significantly longer time consuming frozen copepods. Weight groups >45 g marron spent the longest time resting. FM and frozen copepods were consumed by all weight groups, however, weight groups <15 g and 15−30 g rejected the BSF. The number of frozen copepods consumed by marron were significantly higher for <30 g marron and lowest in 60−100 g marron weight group. In conclusion, the post feeding activities and feed preference of marron were weight dependent.