Interactive effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada mazatlanica

The combined effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada mazatlanica at the hatchery were investigated. Specimens were subjected to a combination of four temperatures (20, 23, 26 and 29 °C) and five microalgal diets ( Isochrysis galbana alone, I. galbana + Pavlova salina, I. galbana + Chaetoceros muelleri, C. muelleri + P. salina and I. galbana + P. salina + C. muelleri ). An increase in shell height occurred in a linear pattern, while wet weight gain fitted a power law. Temperature, more than diet, exerted a stronger influence on the growth and condition of the specimens. The combination of 29 °C with P. salina+C. muelleri led to the fastest growth in shell height, while the combination of 29 °C with I. galbana + C. muelleri led to the highest wet and dry weight biomass. In contrast, specimens grew significantly less in shell height and wet weight at 20 °C, regardless of the diet. At all temperatures, the monoalgal diet of I. galbana led to the slowest growth of specimens, but in turn favoured the highest levels of protein, carbohydrate and lipid reserves as a possible strategy to store more energy reserves under stressful events.