Effects of Elevated Temperature and Carbon Dioxide on the Growth and Survival of Larvae and Juveniles of Three Species of Northwest Atlantic Bivalves

Rising CO2 concentrations and water temperatures this century are likely to have transformative effects on many coastal marine organisms. Here, we compared the responses of two life history stages (larval, juvenile) of three species of calcifying bivalves (Mercenaria mercenaria, Crassostrea virginica, and Argopecten irradians) to temperatures (24 and 28°C) and CO2 concentrations (∼250, 390, and 750 ppm) representative of past, present, and future summer conditions in temperate estuaries. Results demonstrated that increases in temperature and CO2 each significantly depressed survival, development, growth, and lipid synthesis of M. mercenaria and A. irradians larvae and that the effects were additive. Juvenile M. mercenaria and A. irradians were negatively impacted by higher temperatures while C. virginica juveniles were not. C. virginica and A. irradians juveniles were negatively affected by higher CO2 concentrations, while M. mercenaria was not. Larvae were substantially more vulnerable to elevated CO2 than juvenile stages. These findings suggest that current and future increases in temperature and CO2 are likely to have negative consequences for coastal bivalve populations

Evaluation of different pre-slaughter light intensities and fasting duration in broilers

The aim of this study was to determine the effects of different levels of light intensity (0, 5 or 20 lx) and different pre-slaughter feed fasting duration (3, 6, 9, 12 and 15 hours) on the parameters body weight loss, carcass yield, commercial cuts yield, water carcass retention, bacterial counts and breast meat pH. A number of 72 broiler chickens at 45 days of age (Cobb 500 strain) was distributed in three chambers, in a total of 24 broilers per chamber. The results showed that feed fasting significantly influenced (p<0.05) body weight losswhen broilers were submitted to 9 hours of fasting. Broilers kept in the chamber with 0 lx presented higher body weight loss compared with other light intensities. The results showed an increase in carcass yield (p<0.05) as pre-slaughter feed fasting duration increased, but it did not affect commercial cuts yield or breast meat pH (p>0.05). The presence of feed in the crop and gizzard did not depend on light intensity, but was affected by pre-slaughter feed fasting duration. Bacterial counts decreased with feed fasting duration (p<0.05)