@article { author = {Khan, Imtiaz}, title = {Effects of feeding levels on growth performance, feed utilization, body composition, energy and protein maintenance requirement of fingerling, rainbow trout, Oncorhynchus mykiss (Walbaum 1792)}, journal = {Iranian Journal of Fisheries Sciences}, volume = {17}, number = {4}, pages = {745-762}, year = {2018}, publisher = {Agricultural Research,Education and Extension Organization}, issn = {1562-2916}, eissn = {2322-5696}, doi = {10.22092/ijfs.2018.119209.}, abstract = {A 10-week feeding experiment was conducted to evaluate the effects of feeding level, energy and protein maintenance requirement of rainbow trout, Oncorhynchus mykiss, fingerling (5.65±0.45cm; 1.42 ±0.25g) by feeding casein-gelatin based purified diet (45% CP; 3.67 kcal  g-1 GE) at six feeding levels 2-7% of BW/day in two equal meals, at 0800 and 1700 h, in triplicate, with 20 fish per trough fitted with continuous water flow-through system water volume 60L. Maximum live weight gain, best-feed conversion ratio (FCR), best specific growth rate (SGR) and highest protein efficiency ratio (PER) were reported with fish fed 4-5% BW day-1. However, quadratic regression analysis for weight gain, FCR, PER, protein retention efficiency (PRE) and energy retention efficiency (ERE) data indicated the break-points occurred at 5.33, 4.50, 4.48, 4.63 and 4.74% BW day-1, respectively. Body composition also produced significant (p<0.05) differences with respect to each feeding level, maximum protein, lowest moisture and intermediate fat contents were reported at 4-5% feeding levels. Protein and energy retention values also produced significant (p<0.05) difference among each feeding level with maximum values were reported at 5% feeding level. Based on the above results, it is recommended that feeding in the range of 4.6 to 5.3% BW day-1, corresponding to 2.07-2.39g protein and 16.88-19.45 kcal energy g100g-1 of the diet day-1 is optimum for the growth and efficient feed utilization of rainbow trout, while 2-3% feeding levels (0.90-1.35g protein and 7.34-11.01 kcal energy) suggests that these amounts approximate the maintenance requirement of fish.}, keywords = {Rainbow trout,Oncorhynchus mykiss,Feeding rate,Growth performance,maintenance requirement}, url = {https://jifro.areeo.ac.ir/article_116670.html}, eprint = {https://jifro.areeo.ac.ir/article_116670_391e5e6640e7663eb4d59ba9c29e079d.pdf} }