Morphophysiological responses of Octopus tehuelchus juveniles during the transition period between endogenous and exogenous feeding
Por:
Braga, Ramiro, van der Molen, Silvina, Rodriguez, Yamila E., Fernandez-Gimenez, Analia V., Battini, Nicolas, Rosas, Carlos, Ortiz, Nicolas
Publicada:
15 jul 2022
Categoría:
Aquatic science
Resumen:
In cephalopod hatchlings there is a transitional period considered
critical, in which the digestive system undergoes morphophysiological
changes associated with the passage from the consumption of vitelline
reserves to an independent feeding. During this period, the
characterization of the digestive dynamics and growth is key information
to define their nutritional requirements under culture. Octopus
tehuelchus, which has become increasingly interesting for cultivation,
is a species endemic to South America with holobenthic development and
large juveniles. In this work, the enzymatic and cytological changes of
the digestive gland (DG) along with the variation in body weight and
size of O. tehuelchus hatchlings were evaluated when reared at 16 ?
under two feeding treatments: fed with the isopod Exosphaeroma sp. and
starved. In fed juveniles, the predatory activity began a few hours
after hatching; and up to 6 days post hatching (DPH) there was neither
somatic growth nor cellular differentiation of the DG, but there was an
activation of acid enzymes. From 6 to 10 DPH, there was an increase in
the size and weight of juveniles, and the maturation of the DG began
with the appearance of heterolysosomes and heterophagosomes.
Furthermore, lipases activity reached its maximum level and there was a
considerable increase in both alkaline phosphatases and peptidases. From
15 to 25 DPH, the DG became fully mature and the lipase activity reached
minimum levels, while the alkaline peptidases continued increasing. At
the end of the experiment, at 25 DPH, fed juveniles doubled their
weight. In the starved juveniles, neither somatic growth nor cytological
differentiations of the DG were registered. Besides, in this treatment,
acid phosphatases and lipase activities (i.e. enzymes related to yolk
consumption) remained at basal levels or decreased over time, even with
yolk platelets still present, suggesting that the consumption of yolk
reserves would be delayed, regulating the survival time. In fed
juveniles, the ingestion of isopods seems to act as a modulating factor
of the digestive activity, triggering an increment in the activity of
lipases, acid phosphatases, as well as alkaline peptidases which are
related to the digestion of exogenous food. It is concluded that
morphological and physiological changes during the digestive maturation
are related to the ingestion of Exosphaeroma sp. In this sense, this
isopod species would be a suitable food which promotes the rapid growth
of O. tehuelchus during their early post-hatching stage under culture.
Filiaciones:
Braga, Ramiro:
Inst Biol Organismos Marinos IBIOMAR, Lab Cefalopodos, CONICET, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
Univ Nacl Patagonia San Juan Bosco, Ciudad Univ,25 Mayo km 4, RA-9000 Comodoro Rivadavia, Chubut, Argentina
van der Molen, Silvina:
Inst Biol Organismos Marinos IBIOMAR, Lab Cefalopodos, CONICET, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
Rodriguez, Yamila E.:
Inst Invest Marinas & Costeras, FCEyN, UNMdP CONICET, CC1260, RA-7600 Buenos Aires, Argentina
Fernandez-Gimenez, Analia V.:
Inst Invest Marinas & Costeras, FCEyN, UNMdP CONICET, CC1260, RA-7600 Buenos Aires, Argentina
Battini, Nicolas:
Inst Biol Organismos Marinos IBIOMAR, Grp Ecol Ambientes Costeros, CONICET, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
Rosas, Carlos:
Univ Nacl Autonoma Mexico, Fac Ciencias, Unidad Multidisciplinaria Docencia Invest, Puerto abrigo s-n, Hunucma 97350, Yucatan, Mexico
Ortiz, Nicolas:
Inst Biol Organismos Marinos IBIOMAR, Lab Cefalopodos, CONICET, Blvd Brown 2915, RA-9120 Puerto Madryn, Chubut, Argentina
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