Supranutrition of microalgal docosahexaenoic acid and calcidiol improved growth performance, tissue lipid profiles, and tibia characteristics of broiler chickens.

BACKGROUND: Docosahexaenoic acid (DHA) and calcidiol could be enriched in chicken for improving public nutrition and health. It remains unclear if supranutritional levels of DHA and calcidiol impair growth performance or metabolism of broiler chickens. This study was to determine singular and combined effects of high levels of supplemental DHA-rich microalgal biomass or oil and calcidiol on growth performance, concentrations of triglycerides, cholesterol, and nonesterfied fatty acids in plasma, liver, breast, and thigh, and biophysical properties of tibia. METHODS: In Exp. 1, 144 day-old Cornish chicks were divided into 4 groups (6 cages/treatment, 6 birds/cage), and were fed a corn-soybean meal basal diet (BD), BD + 10,000 IU calcidiol/kg (BD + Cal), BD + 1% DHA-rich Aurantiochytrium (1.2 g DHA/kg; BD + DHA), and BD + Cal + DHA for 6 weeks. In Exp. 2, 180 day-old chicks were divided into 5 groups, and were fed: BD, BD + DHA (0.33% to 0.66% oil, 1.5 to 3.0 g DHA/kg), BD + DHA + EPA (1.9% to 3.8% eicosapentaenoic acid-rich Nannochloropsis sp. CO18, 0.3 to 0.6 g EPA/kg), BD + DHA + calcidiol (6000 to 12,000 IU/kg diet), and BD + DHA + EPA + Cal for 6 weeks. RESULTS: Birds fed BD + Cal diet in Exp. 1 and BD + DHA + EPA diet in Exp. 2 had higher (P < 0.05) body weight gain (10%-11%) and gain:feed ratio (7%), and lower (P < 0.05) total cholesterol and triglyceride concentrations in plasma (18%-54%), liver (8%-26%), breast (19%-26%), and thigh (10%-19%), respectively, over the controls. The two diets also improved (P < 0.05) tibial breaking strength (8%-24%), total bone volume (2%-13%), and (or) bone mineral density (3%-19%) of chickens. CONCLUSION: Supranutrition of dietary calcidiol and DHA alone or together did not produce adverse effects, but led to moderate improvements of growth performance, lipid profiles of plasma and muscle, and bone properties of broiler chickens.

Seasonal influence of scallop culture on nutrient flux, bacterial pathogens and bacterioplankton diversity across estuaries off the Bohai Sea Coast of Northern China.

In this study, we investigated the environmental impacts of scallop culture on two coastal estuaries adjacent the Bohai Sea including developing a quantitative PCR assay to assess the abundance of the bacterial pathogens Escherichia coli and Vibrio parahaemolyticus. Scallop culture resulted in a significant reduction of nitrogen, Chlorophyll a, and phosphorous levels in seawater during summer. The abundance of bacteria including V. parahaemolyticus varied significantly across estuaries and breeding seasons and was influenced by nitrate as well as nutrient ratios (Si/DIN, N/P). Bacterioplankton diversity varied across the two estuaries and seasons, and was dominated by Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes. Overall, this study suggests a significant influence of scallop culture on the ecology of adjacent estuaries and offers a sensitive tool for monitoring scallop contamination.