Comparing feed intake, utilization of protein and energy for growth and body composition in S. solea fed natural and commercial diets

The present work was carried out to study the effect of polychaete Nereis virens on feed intake, utilization of protein and energy for growth and body composition in sole (S. solea). It is hypothesized that intake, efficiencies of protein utilization and growth rates obtained for sole fed ragworm are comparable to those previously reported for S. solea. The mussel M. edulis was used as a reference diet to allow comparisons of present results with those obtained previously, which until today serve as reference for optimum growth in sole. Intake, efficiencies of utilization for protein and energy for growth and growth rates obtained for sole fed ragworm are expected to be higher compared to commercial feed. A commercial feed, commonly used for turbot but also in sole culture served as a second reference diet to discuss differences between natural and commercial feeds

Efficacy of insect larval meal to replace fish meal in juvenile barramundi, Lates calcarifer reared in freshwater

The present experiment was conducted to evaluate the efficacy of dietary protein from black soldier fly, Hermetia illucens, larval meal (BSFL) to replace fish meal (FM) protein in juvenile barramundi, Lates calcarifer. Larvae of black soldier fly were fed with the underutilised crop, sesbania, Sesbania grandiflora. Five isonitrogenous (44% crude protein) and isocaloric (16.0 kJ available energy/g) experimental diets were formulated to replace FM using processed BSFL meal at 0 (control), 25% (BSFL25), 50% (BSFL50), 75% (BSFL75) and 100% (BSFL100). Data for proximate and amino acid analysis suggested BSFL meal as an inferior protein ingredient than FM, but parallel to soybean meal. At the end of 8 weeks of fish feeding trial, there were no significant differences in the average weight gain (WG) and specific growth rate among the group of fish-fed control, BSFL25 and BSFL50 diets (P < 0.05). Although numerical differences were recorded in the fish whole-body proximate composition, crude protein and moisture content were not much affected by the different dietary treatments. Essential amino acids including arginine, histidine, lysine and methionine were found to be higher in the whole body of fish-fed BSFL100 diet. Broken line regression analysis of average WG showed an optimum FM replacement level of 28.4% with BSFL meal. Therefore, the present experiment clearly demonstrates that the maximal dietary inclusion level of BSFL meal as FM protein replacer for the optimum growth of juvenile barramundi reared in freshwater could be greater than 28.4% but less than 50%, without any adverse effects on the fish whole-body proximate and amino acid composition

Feed intake, growth and nutrient retention of common sole (Solea solea L.) fed natural prey and an artificial feed

This study compares growth, intake and retention efficiencies of nutrients and energy between common sole (Solea solea L.) fed ragworm (Nereis virens, Sars), blue mussel (Mytilus edulis L.) and an artificial (commercial) feed. Food types were fed to common sole (mean initial body weight: 44.9 ± 2.3 g) in excess three times a day over a 54-day-period. The growth rate in common sole fed the natural prey (8.5 g kg-0.8 d-1) was significantly higher compared to the growth rate in fish fed the artificial feed (5.1 g kg-0.8 d-1). Nutrient and energy intake was significantly lower in common sole fed the artificial feed than in fish fed natural prey. The only exception was fat intake which was higher in common sole fed the artificial feed in contrast to fish fed the natural prey. Nutrient and energy retention efficiencies were significantly lower in common sole fed the artificial feed than in fish fed the natural prey. In conclusion, the low growth in common sole fed the artificial feed was related to lower nutrient and energy intake as well as lower nutrient and energy retention efficiencies. It is suggested that reduced intake of the artificial feed might be related to the high dietary fat content of the artificial feed

Comparing feed intake, utilization of protein and energy for growth and body composition in S. solea fed natural and commercial diets

The present work was carried out to study the effect of polychaete Nereis virens on feed intake, utilization of protein and energy for growth and body composition in sole (S. solea). It is hypothesized that intake, efficiencies of protein utilization and growth rates obtained for sole fed ragworm are comparable to those previously reported for S. solea. The mussel M. edulis was used as a reference diet to allow comparisons of present results with those obtained previously, which until today serve as reference for optimum growth in sole. Intake, efficiencies of utilization for protein and energy for growth and growth rates obtained for sole fed ragworm are expected to be higher compared to commercial feed. A commercial feed, commonly used for turbot but also in sole culture served as a second reference diet to discuss differences between natural and commercial feeds