Effects and mechanism of feeding microalgae oil on the structure and quality of milk fat

Ruminant milk fat mainly consists of saturated fatty acids (SFA) and lacks docosahexaenoic acid (DHA) and other essential polyunsaturated fatty acids (PUFA). Docosahexaenoic acid is a kind of PUFA, which plays an important role in mental development, improving immunity and improving cardiovascular and cerebrovascular health. Currently, the main sources of DHA for human are microalgae and fish supplements. These supplements have a limited shelf life due to the oxidation of DHA over time. A solution to include DHA in dairy products, like infant formula, and to increase the shelf life of DHA is feeding DHA-rich microalgae supplements to dairy animals. Feeding microalgae to dairy animals results in DHA in milk fat that is coated in the fat globule membrane, which has a relatively stable storage characteristic. From the perspective of the dairy animal, supplementation of saturated and unsaturated lipogenic nutrients can be expected to affect the physiological state of lactating dairy cows and goats. The effect of dietary fat on milk fat composition and lactation lipid metabolism of dairy cows and goats is not completely clear due to multiple mechanisms of rumen biohydrogenation, fatty acid absorption by the small intestine, and uptake by the mammary epithelial cells. This project aims to explore the effects of lipid supplementation on the physiological state and milk fat composition of dairy cows and goats, and systematically analyse milk fat secretion pathways, changes in milk fat composition and content, and its biological functions. Metabolomics will be used to explore the dynamic impact of different dietary fat sources, including microalgae, on physiology of cows and goats during lactation. Mouse behaviour experiments and metabolite detection explore the biological functions of endogenous-DHA milk. Ultimately, this project aims at providing important knowledge for the design of nutritional and healthy dairy products that are beneficial to consumers of all ages.