Combined Supplementation of Rumen-Protected Algae Powder and Rumen-Protected Choline Increases Docosahexaenoic Acid Content in Goat Milk

Docosahexaenoic acid (DHA) is an essential omega-3 polyunsaturated fatty acid with important health benefits. However, DHA enrichment in ruminant milk is limited by inefficient post-absorptive transport. This study evaluated whether combined supplementation of rumen-protected algae powder (RPA) and rumen-protected choline (RPC) enhances DHA enrichment in goat milk. Nine lactating dairy goats were assigned to three groups (n = 3/group) for 28 days: RPA alone, RPA + low-dose RPC (5 g/d), and RPA + high-dose RPC (10 g/d). Milk DHA content, bioconversion efficiency, serum biochemical parameters, and lipid profiles were analyzed. Compared with RPA alone, low- and high-dose RPC increased milk DHA content to 27.98 and 33.50 mg/100 mL, respectively, representing increases of 23.0% and 47.3%, and enhanced DHA bioconversion efficiency to 20.66% and 24.29% compared with 16.86% in the RPA group. RPC supplementation increased serum VLDL and triglyceride concentrations, and lipidomics revealed increased DHA-containing triglycerides (TG-DHA). These findings suggest that RPC may enhance DHA enrichment in goat milk by promoting VLDL-mediated DHA transport. Further studies with larger animal populations are required to confirm these effects. These findings contribute to a better understanding of nutritional regulation of DHA transfer and provide insights into strategies for developing DHA-enriched dairy products.