Optimum Dietary Protein and Lipid Levels in Juvenile Filefish, Stephanolepis cirrhifer, Feed

Abstract

A feeding trial was designed to assess the effects of dietary protein and lipid content on growth, feed utilization efficiency, body composition, and hematological indices of juvenile filefish, Stephanolepis cirrhifer. Eight experimental diets were formulated with a combination of four protein (35, 40, 45, and 50%) and two dietary lipid levels (7 and 14%). Each diet was fed to triplicate groups of fish (3.2 ± 0.06 g) to apparent satiation for 8 wk. Fish growth performance and feed utilization were significantly affected by increasing dietary protein and lipid levels, with no significant interactions between factors. The highest growth performance value, in terms of weight gain, was observed in groups fed the diets with 50% protein (399%). However, fish fed the diet containing 45% protein had comparable growth (357%) while achieving relatively higher protein efficiency ratio. Hepatosomatic index was significantly affected by interaction of dietary lipid and protein with the highest values observed in those fish fed the highest protein (45–50%) and lipid (14%) diets. There was a significant increase in body lipid content (5.1 to 6.6%) and a decrease in body protein (15.8 to 14.8%) and ash (2.47 to 2.16%) with increasing dietary lipid levels from 7 to 14%. Muscle lipid content was significantly affected by both dietary protein and lipid levels and tended to increase with increasing dietary protein and lipid levels, ranging from 0.13 to 1.20%. Liver lipid content (65.9 to 68.7%) was significantly increased with the increase in dietary lipid levels while liver moisture content (28.9 to 25.9%) showed a clear decreasing trend. Hematological values were also altered with the increase in either dietary protein or lipid levels. These findings may suggest that a diet containing 45% protein and 7% lipid, with a protein to energy ratio of 23.8 mg/kJ, could deliver sufficient nutrient and energy to support acceptable growth and feed utilization and avoid excessive fat deposition in juvenile filefish.

Consumption of monogenean eggs by crustaceans and fish

“…In this regard, S. cirrhifer is also a very promising biocontrol agent. Aquaculture and hatchery production of S. cirrhifer is becoming increasingly popular in Japan and few other countries (An et al., 2011; Khosravi & Lee, 2017; Miyajwia‐Taga et al., 2016). Combining their high market value and high performance in skin fluke egg consumption, this species could be a good target for multispecies aquaculture.…”

Changes in Growth and Feeding Characteristics during Early Ontogenesis in Threadsail Filefish, Stephanolepis cirrhifer

“…Accordingly, the species was added to the IUCN Red List of Threatened Species in 2017 [5]. Recent studies on the species have mainly focused on its external morphology [6,7] and the required nutrient levels [8,9] of this species.…”