Nutritional and Bioenergetic Considerations in the Development of the American LobsterHomarus americanus

Abstract

To better understand the early life history stages of the American lobster Homarus americanus, nutritional and bioenergetic aspects of development have been investigated. These studies focused on physiological and biochemical processes during transitional periods between extrusion of the eggs, hatching, larval development, molting, metamorphosis, and attainment of the juvenile stage. Biochemical changes during embryogenesis reflect catabolism of various substrates for energy. Exposure to different thermal regimes resulted in considerable variation in the rates of utilization of energy substrates during embryogenesis. Embryos raised at elevated temperatures had yolk remaining at the time of hatching. The first three larval stages have similar energy requirements. Lipid is of prime importance and the turnover rate for lipid can be rapid. Weight-specific metabolism increases with successive larval stages, in stage IV lobsters, the dependency on lipid as a substrate is diminished and lipid reserves serve a storage function. Metabolic rates of premolt stage IV lobsters are decreased in comparison with earlier stages. These changes in physiology correlate with changes in the developing midgut gland, specifically with the appearance of droplets of lipid in the lipid-storing cells of the midgut gland of stage IV lobsters. By stage VI, lobsters have energy storage and metabolic patterns similar to those of adults, and the midgut gland has the adult morphology. The transitions from hatching to attainment of the juvenile form are reflected in differences in physiological and biochemical processes that influence food selection and diet.

Modelling developmental changes in the carbon and nitrogen budgets of larval brachyuran crabs

“…In subsequent larval instars of H. araneus, the average O/N ratio decreases . The same tendency was found in larval lobsters (Sasaki et al, 1986) and crabs (Mootz & Epifanio, 1974;Johns, 1982). In mud crab larvae, Levine & Sulkin (1979) measured extremely low O/Nratios, which suggests an overestimation of ammonia excretion.…”

“…Hence, a maximum atomic O/N ratio was found near ecdysis (postmoult, late premoult), and a minimum in intermoult and early premoult . The only comparable data available for other larval decapods (Sasaki et al, 1986) reveal a similar pattern, although not so clearly. This possible general pattern in the O/N ratio suggests that larvae metabolize proportionally more lipids and/or carbohydrates near ecdysis, but more protein in the middle of the moult cycle.…”

“…The green crab (Car-9 Biologische Anstalt Helgoland, Hamburg cinus maenas; , the mud crab (Rhithropanopeus harrisii; Levine & Sulkin, 1979), the rock crab (Cancer irroratus; Johns, 1982), the American lobster (Homarus americanus; Logan & Epifanio, 1978;Sasaki et at., 1986), and the spider crab (Hyas araneus; Anger et al, 1989) may be considered model species for such studies. In the last mentioned paper, biochemical and physiological data were reviewed that had been obtained during the past ten years in a number of investigations with 14. araneus larvae.…”

Bioenergetics of early life-history stages of the brachyuran crab Cancer setosus in response to changes in temperature

“…In the spiny lobster Jasus edwardsii and the crayfish Cherax quadricarinatus an increase in egg incubation temperature led to a higher consumption of lipids and certain fatty acids (mainly 20:5(n-3)) (Smith et al, 2002;García-Guerrero et al, 2003). On the other hand, in the American lobster Homarus americanus less lipids were utilized with higher egg incubation temperature (Sasaki et al, 1986). Lipids and fatty acids contribute about 20-30% to egg-composition (protein 15-25%, salts 2-5%, remainder water), and frequently form the most important source of metabolic energy in decapod crustacean eggs (Pandian, 1994).…”

Developmental changes in the structure and function of lobster hemocyanin

“…Stage I -III larvae utilize lipid reserves rapidly, but stage IV animals store lipids and utilize more protein. The maximum dry weight to wet weight ratio is the same for each of the first three stages, then increases for stage IV (Sasaki et al, 1986). Both maximum swimming speed and duration for which speeds can be maintained are much higher for postmetamorphic than pre-metamorphic animals (Ennis, 1986).…”