Improving feed efficiency in fish using selective breeding: a review

Abstract

Improving feed efficiency (FE) is key to reducing production costs in aquaculture and to achieving sustainability for the aquaculture industry. Feed costs account for 30–70% of total production costs in aquaculture; much work has been done on nutritional and husbandry approaches to improve FE but only a limited amount of research has been devoted to using genetics, despite its potential. This paper reviews past work to improve FE in fish using selective breeding and assess future directions. Direct selection on FE traits requires methods to measure individual feed consumption and estimate FE efficiently and accurately. This is particularly difficult to do in fish because of the environment in which they live. Many of the published studies on FE were found to be inaccurate because of methodological problems. The relatively low heritability estimates of FE traits in fish published to date are probably partly as a result of inaccurate measurements of feed intake. Improving ways to measure the individual feed intake with high accuracy will be critical to the successful application of genetics to improving FE. Indirect selection criteria that could be used to improve FE (including growth after starvation/refeeding, body composition, neuropeptides or hormone levels) are discussed. Promising approaches to measuring feed intake accurately that may enable these studies to be undertaken are identified. More work using these will be needed prior to assessing the practicality of the introduction of direct or indirect traits for FE in fish genetic improvement programmes.

The Future of Aquatic Protein: Implications for Protein Sources in Aquaculture Diets

“…Improving animal performance and animal health is a key to not only reducing aquaculture production costs but also reducing environmental impacts including decreasing carbon footprints. 147,148 Traditionally, in aquaculture to date, this has been implemented through the optimization of feed formulations to achieve the most efficient feed conversion ratios (FCRs), which represent the quantity of feed consumed to produce one unit of animal biomass gain. The optimization of FCRs is based on maximizing animal survival and growth traits.…”

“…The optimization of FCRs is based on maximizing animal survival and growth traits. 148 However, for species that require relatively large quantities of fish meal and fish oil in their diets, this can be environmentally and economically unsustainable given the limited fishery resources. 149,150 A sustainable solution would be for farmed animals to be fed renewable plant-sourced and emerging alternative protein and oil products, while at the same time improving FCRs and other production traits through husbandry, species-specific feed formulation, functional feed additives, and selective breeding practices and their interaction (i.e., genotype 3 diet interaction).…”

First Evidence of Realized Selection Response on Fillet Yield in Rainbow Trout Oncorhynchus mykiss, Using Sib Selection or Based on Correlated Ultrasound Measurements

“…Among those traits, disease resistance is more and more included in selective breeding programs (Gjedrem, 2015). Feed conversion efficiency is also considered an important production efficiency trait, but remains difficult to improve by selective breeding in aquaculture, due to the inability to precisely record individual feed intake in the production environment, where fish are reared in large groups (de Verdal et al, 2018). Fillet yield, the ratio of edible fillet weight to body weight, has raised less interest.…”

Intelligent feeding control methods in aquaculture with an emphasis on fish: a review

“…With the continuous expansion of intensive farming, the proportion of expenses related to feed costs has increased (de Verdal et al . ). For example, expenses have increased by 40–50% for Atlantic salmon (Liu et al .…”

“…By 2030, nearly two-thirds of the fish consumed globally will be provided by aquaculture (Bank 2013;FAO, 2016). With the continuous expansion of intensive farming, the proportion of expenses related to feed costs has increased (de Verdal et al 2017). For example, expenses have increased by 40-50% for Atlantic salmon (Liu et al 2014;Føre et al 2016), by 60-80% for carp farming (Føre et al 2011;Wu et al 2015) and by up to 86% for some other species (catfish: 81-86%) (Rola & Hasan 2007).…”