Fish as feed inputs for aquaculture: practices, sustainability and implications

Wild fish and other aquatic organisms as feed in aquaculture in Europe 233

Typical inclusion rates for fishmeal in animal diets are around 2–10 percent for

terrestrial animal species. Efficiencies of conversion of feed to live weight gain are

usually quoted in terms of FCR (units of weight gain per unit of feed consumed). In

general, efficiencies of feed conversion are higher for fish at 30 percent as compared

with poultry, pigs and sheep, 18 percent, 13 percent and 2 percent, respectively (Asgard

and Austreng, 1995). It is important to note, however, that with the lower inclusion

rates of fishmeal in poultry and pig diets, these species requires less fishmeal than do

fish to produce a kilogram of edible product.

The use of fishmeal in ruminant diets^8

Although sheep and cattle consume diets that are predominantly forage-based, there is

increased use of concentrate diets and supplements at times of increased productivity,

such as during pregnancy and lactation and during rapid growth. The use of fishmeal

in these situations has considerable advantages over other protein sources such as

soybean meal and bone meal in supplying RUP at times when metabolizable protein

requirements may be greater than those that can be supplied by microbial protein

synthesis and forage RUP.

Use of fishmeal in diets of non-ruminants

Fishmeal use in pig diets accounts for approximately 20 percent of total fishmeal use,

and it is recognized as a key protein source with a good balance of essential amino

acids. Pigs’ diets containing fishmeal show improved feed conversion efficiencies and

generally produce leaner carcasses (Wood et al., 1999). The protein is well tolerated in

pigs of all ages and has a high digestibility. As with fishmeal used in ruminant diets,

however, processing has a significant impact on protein quality in pig diets. Excessive

heat treatment results in a significant reduction in digestibility and biological value,

due mainly to loss of lysine, a key limiting amino acid in growing pigs. One major

environmental benefit in the use of fishmeal in pig diets is the high digestibility of

the added protein, resulting in an improved efficiency of dietary protein use with a

concomitant reduction in the production of high N-containing effluent.

Use of fishmeal in diets of poultry

As with diets for mammalian species, fishmeal is considered a natural, balanced

ingredient for poultry diets with a high protein, high mineral and high micronutrient

TABLE 16

Fishmeal and fish oil use in world agriculture, 2002 and 2010 (predicted)

A. fishmeal usage (2002 and 2010 (predicted)) B. Fish oil usage (2002 and 2010 (predicted))

Consumer

Fishmeal use (thousand tonnes)

Consumer

Fish oil use (thousand tonnes)

2002 2010 Change in use (%) 2002 2010 Change in use (%)

Poultry 1 755 975 -44 Edible 375 175 -53

Pigs 1 885 1 430 -24 Industrial 150 88 -41

Ruminants 65 – -100 Pharmaceutical 25 – -100

Others 585 975 67 Total 550 263 -52

Total 4 290 3 380 -21

Source: Barlow (2002)

(^8) Currently, the inclusion of fishmeal and fishmeal products in feed for ruminant animals is banned under
EU legislation as a consequence of the bovine spongiform encephalopathy (BSE) crisis. While there is no
inherent risk of the transfer of transmissible spongiform encephalopathies (TSE) from fishmeal, the ban
was introduced in response to fears about possible contamination of fishmeal products with processed
animal proteins.