Use of grape pomace in formulated feed for the rainbow trout fry, Oncorhynchus mykiss (Walbaum, 1792)

Abstract

Two different experiments with rainbow trout fry were carried out to evaluate the effect of different grape pomace (GP) levels in feed on growth performance and apparent digestibility. The first experiment used 0, 20, 40, and 60 g kg −1 GP (D0, D2, D4, and D6, respectively); the second experiment used 0, 60, 120, and 180 g kg −1 GP (D0, D6, D12, and D18, respectively). Total polyphenols in the diet ranged from 0 to 8.19 mg g −1 in D0-D18. At the end of the first and second experiments (83 days and 77 days, respectively), no significant differences in fish growth were observed between the different diets.On the other hand, feed containing up to 2.7 mg g −1 total polyphenols (D6) showed a significantly higher digestibility relative to feed with more than 5.5 mg g −1 total polyphenols (D12). Our findings suggest that the inclusion of GP at levels of up to 18% in feed for Oncorhynchus mykiss fry did not affect growth parameters. However, it did influence apparent digestibility; fry that consumed diet D6 showed benefits in terms of nutrient digestibility and feed conversion efficiency. K E Y W O R D S apparent digestibility, feed, grape pomace, polyphenols, rainbow trout

Fruit processing by‐products in the aquafeed industry: A feasible strategy for aquaculture sustainability

“…Zamani et al 25 also stated that after grape seed oil supplementation, the growth performance and α‐amylase activity increased, whereas trypsin, total alkaline protease, and lipase activities decreased in rainbow trout. Lastly, after including grape pomace (18%) in rainbow trout diets for 83 days, the apparent digestibility of dry matter and FCR increased 95 …”

“…Lastly, after including grape pomace (18%) in rainbow trout diets for 83 days, the apparent digestibility of dry matter and FCR increased. 95 Grape by-products were also included in the diets of carps. After including dietary GSE (20-30 g/kg) for 56 days, the growth performance, WBCs, total serum protein and globulin, serum and mucus lysozyme activity, total antibody levels, mucus protease activity and mucus antibacterial activity against Aeromonas hydrophila increased.…”

Use of grape by-products in aquaculture: New frontiers for a circular economy application

“…In rainbow trout fry, important supplementation of grape pomace (up to 60 and 80 g/kg) were used. However, no significant differences were observed in fish growth when dietary inclusion of grape pomace was up to 18%, but a higher digestibility and feed conversion efficiency were detected in fry fed the diet supplemented with 60 g/kg of grape pomace [ 81 ].…”

Effects of diets containing grape pomace on the growth, nutrition indices, and the quality traits of common carp (Cyprinus carpio)

“…Fish nutrition management is essential to minimize costs and maximize growth in sustainable aquaculture practice (Ahmad et al, 2018; Daet, 2019; Sangeeta et al, 2018). The use of useful and economical foods is important for the demand for fish feed and to optimize the ingredients for efficient use (Pena et al, 2019).…”