Effects of Rotifers Enriched With Different Enhancement Products on Larval Performance and Jaw Deformity of Golden Pompano Larvae Trachinotus ovatus (Linnaeus, 1758)

Rui Yang,Tao Zhang,Zhenhua Ma,Shengjie Zhou,Zhengyi Fu

doi:10.3389/fmars.2020.626071

Abstract

This study evaluated the effects of rotifers enriched with three enhancement products (Nannochloropsis, S.presso, and Algamac 3080) on the body fatty acid composition, growth, survival, jaw deformity, and bone development-related gene expression of the golden pompano larvae. The rotifers enriched with Nannochloropsis were rich in EPA, and the rotifers enriched with S.presso and Algamac 3080 were rich in docosahexaenoic acid (DHA). The level of DHA in Algamac 3080 is higher than that in S.presso. The first feeding started at 3 DPH, and data were collected at 8 DPH. The results showed that the body fatty acid composition of the larvae was basically the same as that of the feeding rotifers. The specific growth rate of S.presso and Algamac 3080 treatment was significantly higher than the un-enriched treatment (P &lt; 0.05). The survival rate of Algamac 3080 treatment was significantly lower than the other treatments (P &lt; 0.05), and the jaw deformity rate of S.presso treatment was significantly lower than the Nannochloropsis and un-enriched treatment (P &lt; 0.05). The expression level of BMP2 and BMP4 in golden pompano larvae were not significantly affected by the enhancement products (P &gt; 0.05), and the expression level of RXRα decreased significantly in the S.presso and Algamac 3080 treatment (P &lt; 0.05). This study indicates that S.presso was an enhancement product more suitable for rotifers for golden pompano larvae. This study provided reliable reference and guidance for the first feeding of golden pompano larvae and also provided more reference data for the study of the mechanism of diet on larval fish bone deformity.

Highlights

In the artificial breeding of marine fish, the choice of feed during first feeding period is important, because they are very vulnerable during this period (Hamre et al, 2013)
On 3 days post-hatching (DPH), larvae were stocked into 12 larval rearing tanks (1000-L) at a density of 40 fish L−1
The amount of EPA (20:5n3) in the rotifers enriched with Nannochloropsis (9.05%) was significantly higher than other treatments (P < 0.05)

Summary

Introduction

In the artificial breeding of marine fish, the choice of feed during first feeding period is important, because they are very vulnerable during this period (Hamre et al, 2013). Some studies have revealed that rotifers lack essential nutrients, so they must be enriched before feeding them to fish larvae (Hamre, 2016; Kotani, 2017). In the enriching of live feeds, polyunsaturated fatty acids (PUFA) such as arachidonic acid (ARA, 20:4 n-6), eicosapentaenoic acid (EPA, 20:3 n-3), and docosahexaenoic acid (DHA, 22:6 n-3) are usually the nutrient components that people pay more attention to. They play an important role in neurological and visual development, and stress resistance (Hernández-Cruz et al, 2015). Recent studies have confirmed that they, especially DHA, are associated with bone and cartilage development in fish and provide a contribution to the prevention of bone deformities (Roo et al, 2009; Izquierdo et al, 2013)

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Conclusion