SHORT & LONG-TERM EFFECTS OF
A NUCLEOTIDE-ENRICHED BROODSTOCK DIET ON THE REPRODUCTIVE PERFORMANCE OF
HADDOCK (Melanogrammus aeglefinus L.)
J.L. Gonzalez-Vecino, C.J. Cutts , R.S. Batty, C.
Mazorra de Quero, P. L. Greenhaff,
S. Wadsworth
Though many efforts are invested
in broodstock nutrition, it is still a poorly understood area of
aquaculture. Regarding reproductive performance of fish, broodstock
nutrition is crucial for egg quality and embryonic development.
Nucleotides (NT) are considered
semi-essential since they can be synthesised endogenously, but
under certain conditions -immunological stress, rapid growth or limited
nutrient intake - might become limiting nutrients. Increasing NT content
in fish diets improves growth, osmoregulation and disease resistance in salmonids,
but may also have beneficial effects on oogenesis
and reproductive performance of broodstock. This study investigates the
short and long-term effects that a NT-enriched diet has on the reproductive
performance of haddock.
Broodstock were fed either a
control or a NT-enriched diet for two consecutive years. Efficacy
of the NT diet was assessed by comparing relative fecundity, egg quality and
egg morphometrics of the different batches from both diets throughout two
spawning seasons. Condition factor, somatic indices and ovarian atresia were
studied in the second year. Relative fecundity improved on a
short-term basis but not in the second year. Egg quality and morphometrics
were improved in both years. Hepatosomatic index was significantly lower with
the NT-diet. Atresia levels and NT content of egg samples are also
discussed.
(Scottish Association for Marine
Science, Marine Farming Unit, Ardtoe, Acharacle, Argyll, PH36
4LD, Scotland, UK, e-mail: jlgv-t@sams.ac.uk)