Reduction of Live Feed in the Early Life of Sea Bream (Sparus aurata, L.) Larviculture: Effects on Enzymatic and Histomorphological Development

Abstract

During the recent years, increasing production costs have caused alternative feeding strategies to reduce costs and increase sustainability in marine fish culture. The fact that live feed production requires high labour force and application has led producers to limitations and the use of new feed additives in this field. In this study, the enzymatic and histological effects of gradual reduction of rotifer (Brachionus plicatilis), which is a live food commonly used in the feeding of gilthead sea bream (Sparus aurata) larvae produced intensively in our country, were investigated. Within the scope of the experiment, a total of 4 experimental groups, one of which was a control group and the remaining three were experimental groups, were designed with three replications. While the amount of rotifer given to the bream larvae in the control group was not decreased, the other experimental groups were reduced by 25, 50 and 75%, respectively. Natura Pro®, a commercial product, was used instead of the reduced amount of live food.  At the end of the experiment, larvae fed with 25 and 50% rotifer reduction had similar growth performance, total protease activity and gastrointestinal histomorphology with the control group receiving full rotifer supplementation and there was no statistical difference (p>0.05). However, 75% reduction in rotifer administration resulted in significantly lower growth rate, enzymatic activity and developmental disorders in gastrointestinal histomorphology and higher mortality, suggesting that rotifer supplementation constitutes a critical threshold for larval health and development (p<0.05). As a result, it was determined that it is economical and meaningful to reduce the live feed by 25% to 50% with the support of additives added by considering the nutritional requirements of the larvae in the early period in sea bream larviculture.