Poultry By-Product Meals as Partial Fish Meal Replacement Yielded Higher Somatic Growth in Alsatian Charr (&amp;lt;i&amp;gt;Salvelinus alpinus X fontinalis&amp;lt;/i&amp;gt;) than Pork or Vegetable-Based Fish Meals

Hannes H. Hager,Martin J. Kainz,Eduard Schneeberger

doi:10.4236/ojas.2018.83014

Abstract

Freshwater salmonids gain increasing popularity as diet fish and are an important dietary source of omega-3 polyunsaturated fatty acids (PUFA) for humans. The aim of this study was to investigate effects of alternative feeds from domestic sources on fish growth and lipid composition of the sparctic Alsatian charr (Salvelinus alpinus X fontinalis), commonly used in freshwater aquaculture in Europe. In this fish feeding experiment, we used a control feed (32% fish meal; feed F1) and experimental diets containing generally only half the amount of fish meal, which was replaced in equal parts by poultry (F2), two different pork by-product meals (F3 and F4), plant-based feeds (F5), or by a feed containing 25% fish and 15% poultry meal (F6) that had a similar caloric value compared to the other feeds. Six hundred charrs of similar initial weight (ca. 90 g) were randomly distributed into 12 tanks (50/tank) of 1.4 m3, supplied with subalpine spring water, and fed one of the feeds. Fish biomass development was the highest in fish fed diet F6, followed by F1, F2, and F5. Pork by-product meals as partial replacement of fish meal resulted on average in a 25% lower biomass gain compared to charr feeding on poultry by-product meal (F6). The use of poultry or pork by-product meals as partial fish meal replacements did not significantly change the total lipids or fatty acids retained in these fish. This study shows that these alternative feeds, with similar lipid sources, had no significant effect on the fatty acid composition in Alsatian charr, however, poultry by-product meal as partial replacement of marine fish meal clearly enhanced charr biomass by 15% relative to conventional fish meals.

Highlights

The global production of freshwater fish, crustaceans, and molluscs increased two-fold within 10 years from 21.8 billion t to 41.7 billion t [1]
This study shows that these alternative feeds, with similar lipid sources, had no significant effect on the fatty acid composition in Alsatian charr, poultry by-product meal as partial replacement of marine fish meal clearly enhanced charr biomass by 15% relative to conventional fish meals
The higher variance in n-6 than n-3 polyunsaturated fatty acids (PUFA) retention in fish among these different feeding treatments suggests that, independent of these diet compositions, Alsatian charr retained n-3 PUFA more consistently than n-6 PUFA. This long-term feeding trial of 180 days furthers our knowledge that reducing marine fish meal by 50% and using poultry by-product meal and vegetable feeds, both used as partial replacements of marine fish meal, results in similar weight gains of this sparctic charr

Summary

Introduction

The global production of freshwater fish, crustaceans, and molluscs increased two-fold within 10 years from 21.8 billion t (in 2001) to 41.7 billion t (in 2010) [1]. Among freshwater salmonids, farming of rainbow trout (Oncorhynchus mykiss) keeps augmenting from 0.5 to 0.7 billion tons (2001-2010) [1]. Such rapidly increasing freshwater fish production requires rapid scientific development of sustainable and economical nutritious diets. Recent research suggests that plant sources as full or partial FM replacement yield similar fish growth as conventional FM feeds [3] [7], there is experimental evidence that marine and freshwater salmonids fed diets with vegetable oils contain less omega-3 (n-3) long-chain polyunsaturated fatty acids (PUFA), in particular docosahexaenoic acids (DHA; 22:6n-3) [8] [9]. It is a scientific challenge to find dietary substitutions that result in similar growth and fatty acid retention in fishes and other consumers (e.g., crustaceans [5]) than conventional FM feeds

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