The Effects of Origanum vulgare L. Essential Oils on Anaesthesia and Haemato-Biochemical Parameters in Mozambique Tilapia (Oreochromis mossambicus) Post-Juveniles

This study investigated the effects of oregano (Origanum vulgare) essential oil (OEO) anaesthesia and stress-related physiological parameters in tilapia mossambicus (Oreochromis mossambicus) post-juveniles. Fish were subjected to different concentrations of OEO (25, 50, 100, and 150 μL L−1) to assess the effects of the anaesthesia and recovery time. A second experiment subjected fish to other handling treatments, including a control (no OEO exposure), ethanol solution, 25 μL L−1 (low effective anaesthesia concentration of OEO), and 100 μL L−1 high effective anaesthesia concentration of OEO) for 10 min to assess the haemato-biochemical indices and survival rate at 0 h and after 24 h. Moreover, all the tested OEO concentrations induced anaesthesia in the studied fish, where the anaesthesia induction time decreased with increased OEO concentrations. Meanwhile, the inverse was reported for recovery time. Based on the ideal anaesthetic criteria, 50 μL L−1 and 100 μL L−1 were the suitable concentrations that could be recommended for quick anaesthesia. However, according to the haemato-biochemical parameters and survival results, 25 μL L−1 was safe to anaesthetise tilapia mossambicus for 10 min and could be recommended for time-consuming fish-handling procedures. Future studies should investigate multiple factors that influence anaesthesia in fish for better optimisation of OEO in tilapia mossambicus

Oral bovine serum albumin administration benefits plasma amino acid profile in blunt snout bream fed high‐fat and high‐energy diet through the TOR signaling pathway

Abstract This study investigated the effect of oral bovine serum albumin (BSA) on plasma amino acid profile and growth performance in blunt snout bream fed high‐fat and high‐energy diets. A total of 360 fish (average weight: 45.84 ± 0.07 g) were randomly divided into three groups in four replicates and fed with the control, high‐fat diet (HFD), and high‐energy diet (HED), respectively. After 12 weeks of feeding, fish were orally administered with 10% BSA for 10 h, with the blood and liver sample obtained at 10 h. The results showed no remarkable difference (p > 0.05) in final weight, weight gain rate, feed conversion ratio, protein efficiency ratio, and daily growth rate among dietary treatments. However, fish fed HFD and HED obtained significantly higher energy and nitrogen retention content than the control. Plasma valine and histidine content were more prevalent in fish fed the control diet than in HFD and HED groups. However, BSA significantly enhanced this content with higher values observed in arginine and alanine content than in control diets at 10 h. Significantly higher liver and plasma Aspartate aminotransferase, Xanthine oxidase, and Glutamate dehydrogenase content were found in the HFD than in the control group. However, the administration of BSA at 10 h improved these parameters similar to the control. Meanwhile, protease, Lipase, aminopeptidase N, carboxypeptidase A, and Na+ K+‐ATPase were influenced significantly (p < 0.001) by sampling time, dietary treatments, and their interaction. Fish fed with the HFD and HED significantly downregulated (p < 0.05) the akt, bcat2, 4e‐bp1, s6k1, and tor expression compared to the control. However, BSA administration at 10 h improved these genes similar to the control. This study indicated that oral BSA administration could benefit plasma amino acid through the TOR signaling pathway in blunt snout bream fed high‐fat and high‐energy diets