Use of two vegetable by-products as protein sources in rainbow trout feeding

1992 ◽  
Vol 55 (2) ◽  
pp. 277-284 ◽  
Author(s):  
F. J. Moyano ◽  
G. Cardenete ◽  
M. de la Higuera

AbstractTwo experiments were designed to test the possibility of partially replacing fish-meal protein in rainbow trout either with maize-gluten meal (MGM) (experiment 1) or potato protein concentrate (PPC) (experiment 2). Rainbow trout (Oncorhynchus mykiss) 30 g initial average weight were given diets containing different levels of MGM or PPC proteins ranging from 0 to 0·4 or to 0·6 of dietary protein, respectively. Substitutions of fish meal either by MGM or PPC were carried out establishing two different total dietary protein levels; 350 and 450 g/kg. Results showed that the MGM diets were acceptable and gave a significant enhancement (over 0·37 in the better case) in nutrient utilization when compared with those including only fish meal. On the contrary, diets including PPC were poorly accepted, and the growth offish and nutrient utilization were negatively correlated with dietary levels of PPC. It is concluded that levels of MGM representing around 400 g/kg diet can be used in foods for rainbow trout, whereas PPC appears not to be a suitable protein source for those fish.

1974 ◽  
Vol 31 (6) ◽  
pp. 1133-1134 ◽  
Author(s):  
Ibrahim H. Zeitoun ◽  
Duane E. Ullrey ◽  
Peter I. Tack

Seven separate diets ranging from 30 to 60% protein in 5% increments were fed for 10 wk to duplicate groups of rainbow trout, Salmo gairdneri, fingerlings maintained at 10 and 20‰ salinity. Water salinity and dietary protein concentration did not significantly influence total serum protein. Hematocrit increased substantially with salinity (35.3% for fish at 10 ppt and 39.1% for those at 20 ppt), whereas different levels of dietary protein were of minor consequence.


2000 ◽  
Vol 83 (6) ◽  
pp. 653-664 ◽  
Author(s):  
Christine Burel ◽  
Thierry Boujard ◽  
Anne-Marie Escaffre ◽  
Sadasivam J. Kaushik ◽  
Gilles Boeuf ◽  
...  

Two rapeseed (Brassica napus) meals, RM1 and RM2, with two levels of glucosinolates (GLS; 5 and 41 μmol/g DM respectively) were incorporated at the levels of 300 and 500 g/kg of the diets of juvenile rainbow trout (Oncorhynchus mykiss) in replacement of fish meal, and compared with a fish-meal-based diet. A decrease in the digestibility of the DM, protein, gross energy and P was observed with high-rapeseed meal (RM) incorporation. In trout fed on RM-based diets, growth performance was reduced even after only 3 weeks of feeding. Feed efficiency was adversely affected by RM and GLS intake. Protein and energy retention coefficients were significantly lower in fish fed on the diet containing the higher level of GLS. P retention was significantly lower with all the RM-based diets than with the fish-meal diet. Irrespective of the degree of growth inhibition, fish fed on RM-based diets exhibited similar typical features of hypothyroid condition due to GLS intake, expressed by lower plasma levels of triiodothyronine and especially thyroxine and a hyperactivity of the thyroid follicles. This hypothyroidal condition led to a strong adjustment of the deiodinase activities in the liver, the kidney and the brain. A significant increase of the outer ring deiodinase activities (deiodinases type I and II respectively) and a decrease of the inner ring deiodinase activity (deiodinase type III) were observed. It is concluded that the observed growth depression could be attributed to the concomitant presence of GLS, depressing the thyroid function, and of other antinutritional factors affecting digestibility and the metabolic utilization of dietary nutrients and energy.


Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1799
Author(s):  
Michaela Schafberg ◽  
Karin Loest ◽  
Andreas Müller-Belecke ◽  
Sascha Rohn

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.


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