Page 20 - AWA Vol.41-No.8

FISHERIES AND FISH FARMING

Broodstock Diets – An Overview

polychaetes polychaete farm – Thailand
Dr. Sagiv Kolkovski
Director Nutrakol Australia
Broodstock condition - encompassing physiological, mackerel, squid, and mussels, polychaetes (for shrimp)
nutritional, and stress-related aspects - is one of the key are often considered essential components of broodstock
factors determining the success of aquatic organism prop- diets.
agation. However, the use of fresh or frozen feeds presents signif-
It is well established that high-quality larvae, exhibiting icant health risks to broodstock, as it is nearly impossible
optimal growth and survival, are directly linked to the nu- to sterilize such feeds completely without compromising
trition and health of the broodstock. their nutritional quality. Typically, these feeds are offered
The effects of nutrients on gonadal development, matu- without any disinfection or preparation.
ration, and fecundity in various aquatic species, includ- In shrimp aquaculture, significant efforts have been
ing fish and crustaceans, have been the subject of exten- made to culture polychaetes, which, together with squid
sive research over the past decades. These studies have and Artemia, are regarded as essential feed items for
focused on protein sources and levels (fish, squid, krill broodstock. Large hatcheries and broodstock centers of-
meals and more recently other protein sources such as ten maintain their own polychaete farms.
black soldier fly meal), lipid sources and fractions (e.g., In recent years, recurrent disease outbreaks caused by
phospholipids), essential fatty acids - particularly HUFAs various pathogens have led the shrimp industry to move
such as DHA, EPA, and ARA - and the appropriate ratios toward more secure feeding options, such as patho-
among them. Vitamins such as ascorbic acid (vitamin C) gen-free pre-packed Artemia and other certified alter-
and α-tocopherol (vitamin E) have also received consid- natives. Nevertheless, global shrimp production still re-
erable attention. In addition, specific nutrients such as lies heavily on live polychaetes and other fresh or frozen
astaxanthin, carotenoids, yeast extracts, and microalgae feeds.
(Spirulina, Chlorella, Dunaliella salina) have been shown
to significantly affect fecundity and are now commonly in- In general, there are no standardized feeding protocols
cluded in commercial broodstock diets. for marine fish broodstock. Nutrition and feeding practic-
es vary greatly among hatcheries and species. A typical
Although a significant body of scientific literature exists
on the nutrition of marine fish and crustacean broodstock, feeding regime includes a mixture of seafoods - such as
sardines, mackerel, and squid - supplemented with com-
many aspects remain poorly understood. Because aqua-
culture involves a large number of species that differ in mercial boosters containing vitamins, minerals, fatty ac-
habitat, behavior, feeding habits, and activity patterns,
there is no single optimal formula that can meet all spe-
cies’ requirements. For instance, the nutritional needs of
flatfish such as Solea solea differ markedly from those of
pelagic species such as Seriola. Likewise, tropical species
such as cobia (Rachycentron canadum) have different re-
quirements from cold-water species such as halibut (Hip-
poglossus sp.).
Although species-specific maturation diets have become
increasingly available in recent years, the nutrition of
broodstock remains far from optimal.
The use of fresh and frozen seafood as partial or com-
plete broodstock diets is still common practice for many
marine species, including established species such as
gilthead sea bream and European sea bass in the Medi-
terranean. While some commercial broodstock diets can Harvesting Artemia for shrimp broodstock – Thailand
be used exclusively, marine organisms such as sardines,
18 Vol. 41 No. 8