Molecular characterization, expression analysis of 14-3-3 beta/alpha and the effect of RNA interference on ion transporter protein Na+-K+-ATPase, Na+–H+-exchanger and CFTR in turbot (Scophthalmus maximus)

Long-Term Phellodendri Cortex Supplementation in the Tiger Grouper (Epinephelus fuscoguttatus): Dual Effects on Intestinal Health Revealed by Transcriptome Analysis

The tiger grouper (Epinephelus fuscoguttatus), an important mariculture fish in Southeast Asia, faces increasing health issues in recent years. Phellodendri Cortex (PC) is a traditional Chinese herbal medicine that exhibits a variety of beneficial effects on tiger groupers. The effects of PC, however, varies with the period of dietary intervention. This study aims to investigate the long-term effects of 1% PC supplementation on tiger groupers, focusing on growth, immunity, disease resistance, and intestinal gene expression. The tiger groupers (with an initial mean weight of 27.5 ± 0.5 g) were fed with a diet of Phellodendri Cortex supplementation and a control diet for 8 weeks. Our results indicate that the long-term PC supplementation did not affect growth or Vibrio disease resistance in tiger groupers. However, the transcriptome analysis revealed potential damage to the structural and functional integrity of the groupers' intestines. On the other hand, anti-inflammatory and cathepsin inhibition effects were also observed, offering potential benefits to fish enteritis prevention and therapy. Therefore, long-term PC supplementation in grouper culture should be applied with caution.

14-3-3ζ and 14-3-3ε are involved in innate immune responses in Pacific abalone (Haliotis discus hannai)

The 14-3-3 proteins play important roles in various cellular processes by binding to different ligands, but little is known about these proteins in mollusks. In this study, two 14-3-3 cDNAs were identified from the Pacific abalone Haliotis discus hannai (designated 14-3-3ζ and 14-3-3ε), possessing 59.40% identity with each other. Both genes were predominantly expressed in the gills of unchallenged abalones, and their mRNA signals could also be detected in several other tissues, including the mantle, hepatopancreas and ovary. However, after Vibrio harveyi challenge, hemocytes were induced significantly (p < 0.01). Meanwhile, phagocytosis was inhibited, but apoptosis, reactive oxygen species formation, and caspase 3 expression were significantly induced (p < 0.01), and they were all suppressed with 14-3-3ζ knockdown (p < 0.01). The differences were that silencing 14-3-3ε reverted the decline in the phagocytic rate derived from bacterial infection, while ROS formation was not influenced significantly. In addition, the expression levels of several antimicrobial peptide and proinflammatory cytokine genes were also decreased with the silencing of 14-3-3 genes. However, with the knockdown of 14-3-3ζ, the expression of 14-3-3ε was further significantly increased (p < 0.01), and vice versa. Overall, our results suggested that 14-3-3ζ and 14-3-3ε should play important roles in innate immunity against V. harveyi infection.