Growth and Heterozygosity in a 12‐Month‐Old Cohort of Ostrea chilensis Obtained by Mass Spawning in the Laboratory

Abstract

Oysters (Osfrea chilensis PHILIPPI 1845). from a 40-month-old cohort which came from the natural population of the Quempillen River Estuary (Southern Chile), were used as parental stock (n = 600) for a hatchery-produced cohort. At 12 months of age this cohort was analysed physiologically (filtration rate, organic ingestion rate, absorption rate, assimilation efficiency, excretion rate, respiration rate) and electrophoretically (multilocus heterozygosity (MLH) using four loci: LAP, GPI, PGM, CA). Most physiological variables were positively correlated with dry weight (P < 0.05). with the exception of assimilation efficiency, excretion size and net growth efficiency (P z 0.05). Also. there was a positive correlation between body size, ingestion rate, absorption rate and net growth efficiency with MLH. Respiration rate and consequently energy losses were negatively correlated with MLH. The energetic efficiency product of a lower metabolic cost in the heterozygous individuals in this cohort is reflected in a higher net growth efficiency and a positive correlation between growth and MLH. The genetic basis for the relationship between metabolic parameters and heterozygosity can be due to an overdominance in this 12-month-old cohort.

The effect of food conditioning on feeding and growth responses to variable rations in fast and slow growing spat of the Manila clam (Ruditapes philippinarum)

“…Values are means ± SD (n = 5). Therefore, present results confirmed most earlier studies in bivalves reporting selection for faster growth to entail faster rates of feeding (Bayne, 1999a(Bayne, , 2000Bayne et al, 1999a,b;Holey and Foltz, 1987;Pernet et al, 2008;Tamayo et al, 2011Tamayo et al, , 2013Tamayo et al, , 2014Toro and Vergara, 1998), a physiological trait associated to larger gill areas in the present species of clams (Tamayo et al, 2011). Moreover, energy conversion efficiencies were higher in F, when compared to S clams, due to lower rates of metabolic energy expenditure per unit of metabolizable energy absorbed.…”

“…It seems to be well established that increasing heterozygosity causes the reduction of the metabolic costs associated to protein deposition (Bayne and Hawkins, 1997;Hawkins et al, 1986Hawkins et al, , 1989 this being a physiological factor contributing to the maximization of energy budget in fast growing individuals. Although such association between faster growth and reduced rates of protein turnover would be expected to result in reduced basal or maintenance metabolic rates in fast growing specimens, available literature has provided contradictory results: for instances, Hawkins (1995), Hawkins and Day (1996); Garton et al (1984), Myrand et al (2009) found significantly lower maintenance metabolic rates in fast as compared to slow growers, however, such a relationship was not found in present study and many others (e.g., Bayne, 2000;Bayne et al, 1999b;Holey and Foltz, 1987;Pace et al, 2006;Tamayo et al, 2011Tamayo et al, , 2013Tamayo et al, , 2014Toro and Vergara, 1998). These studies were performed under different nutritional scenarios that ranged from hatchery conditions (food abundance) to natural conditions (more restrictive in terms of quantity and quality of available food).…”

“…Constitutive (i.e., genetic) differences between fast and slow growing bivalves have long been related to variable degrees of multi-locus heterozygosity (Bayne and Hawkins, 1997;Garton et al, 1984;Hawkins, 1995;Hawkins et al, 1986;Holey and Foltz, 1987;Meyer and Manahan, 2010;Pace et al, 2006;Toro and Vergara, 1998). It seems to be well established that increasing heterozygosity causes the reduction of the metabolic costs associated to protein deposition (Bayne and Hawkins, 1997;Hawkins et al, 1986Hawkins et al, , 1989 this being a physiological factor contributing to the maximization of energy budget in fast growing individuals.…”

“…Such adjustments facilitate increases in the absorption efficiency with little change in gut passage time of food (Bayne et al, 1987;Ibarrola et al, 2000a;Navarro et al, 2009). This phenotypic flexibility in feeding and digestive behavior contrasts with the persistence of physiological differences among groups of individuals conforming differentiated growth categories of possible genetic origin (Bayne, 1999a,b;Bayne et al, 1999a,b;Pace et al, 2006;Pernet et al, 2008;Toro and Vergara, 1998). According to Bayne (2004), characteristics of this contrast would be "considerable behavioral flexibility in response to changes in the food environment, linked with a strong genetic component to growth through a complex synergy of physiological traits" (p. 425).…”

Allozyme heterozygosity, date of first feeding and life history strategy in Atlantic salmon

“…It is thought that increased growth in more heterozygous individuals is a result of increased metabolic efficiency ( e.g. reduced rates of oxygen consumption; Danzmann et al ., 1987; Toro & Vergara, 1998), increased growth efficiency (Toro & Vergara, 1998) or reduced rates of protein turnover (I.D. McCarthy, S.F.…”