Iron supplementation in plant-based aquafeed: Effects on growth performance, tissue composition, iron-related serum parameters and gene expression in rainbow trout (Oncorhynchus mykiss)

Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficients of dry matter, protein, fat, phosphorus, and energy. Protein, phosphorus, and energy retention significantly increased in fish fed the diets with an insect protein meal. In conclusion, the yellow mealworm protein meal could effectively replace 100% of fishmeal in the diet of juvenile rainbow trout with positive effects on its overall zootechnical performance.

Download Full-text

The effects of dietary supplementation of mistletoe (Viscum album) extract on the growth performance, antioxidant, and innate, immune responses of rainbow trout (Oncorhynchus mykiss)

Aquaculture ◽

10.1016/j.aquaculture.2021.736385 ◽

2021 ◽

Vol 536 ◽

pp. 736385

Author(s):

Morteza Yousefi ◽

Mehdi Naderi Farsani ◽

Hamed Ghafarifarsani ◽

Seyed Hossein Hoseinifar ◽

Hien Van Doan

Keyword(s):

Rainbow Trout ◽

Immune Responses ◽

Oncorhynchus Mykiss ◽

Growth Performance ◽

Dietary Supplementation ◽

Viscum Album ◽

Innate Immune ◽

Innate Immune Responses ◽

Rainbow Trout Oncorhynchus Mykiss

Download Full-text

Pike-Perch (Sander lucioperca) and Rainbow Trout (Oncorhynchus mykiss) Fed with an Alternative Microorganism Mix for Reducing Fish Meal and Oil—Fishes’ Growth Performances and Quality Traits

Foods ◽

10.3390/foods10081799 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1799

Author(s):

Michaela Schafberg ◽

Karin Loest ◽

Andreas Müller-Belecke ◽

Sascha Rohn

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Growth Performance ◽

Fish Meal ◽

Control Diet ◽

Sander Lucioperca ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Growth Performances ◽

Pike Perch ◽

Carcass Parameters

In the last decades, several plant-based materials were used for the substitution of fish meal and oil in aquaculture. The present study evaluated the fish quality and the sensory differences of rainbow trout (Oncorhynchus mykiss) and pike-perch (Sander lucioperca) from three different feeding groups, which were fed a commercially available industrial (standard) diet, a control diet, and a special microorganism-based feed mix. This feed mainly consisted of a mix made of Rhodotorula glutinis, Crypthecodinium cohnii, and Arthrospira sp. and had 50% less fish meal and fish oil compared to typical control diets. At the beginning, the pike-perch population was six months old, and the rainbow trout population was 15 months old. The feeding study duration was 16 weeks and every four weeks the growth performance and several morphometric parameters were recorded. Afterwards, sensory evaluation took place to identify possible trends. Sensory evaluation revealed that the rainbow trout groups did not show any significant differences to the standard and control fish fillets with regard to odor, texture, and taste. The effects on rainbow trout growth performances and carcass parameters were similar to the standard group. The feed mix was not optimal for pike-perch farming, which was also reflected by significantly adversely affected growth performance and carcass parameters. The sensorial evaluation showed an opposite trend: here, only small differences in the fillets from the feed mix and standard/control diet were observed.

Download Full-text