Effects of increasing dietary levels of microalgae rich in docosahexanoic acid on ...
| Grant number: | 17/12542-3 |
| Support type: | Scholarships in Brazil - Master |
| Effective date (Start): | October 01, 2017 |
| Effective date (End): | March 31, 2019 |
| Field of knowledge: | Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding |
| Principal Investigator: | Francisco Palma Rennó |
| Grantee: | Júlia Avansi Marques |
| Home Institution: | Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
Abstract The consumption of omega-3 (n-3) fatty acids, considered essential, has been associated with different beneficial effects on animal and human health, and milk presents itself as a potential source. However, despite the possibility of direct conversion of ingested fatty acids to milk fat, several processes involved in the digestion of lipids in ruminants, such as biohydrogenation process, for example, have the ability to alter the digesta fatty acid profile. In addition, lipid supplementation has been associated to reductions in dry matter intake and fat content in milk, and some factors such as the lipid source used, the inclusion and the profile of supplemented fatty acids seem to be determinants of the observed effects. The objective of this study was to evaluate the effect of inclusion of increasing doses of dehydrated microalgae rich in docosahexaenoic acid (DHA) on the diet of dairy cows on nutrient intake, total apparent digestibility of nutrients, production, composition and profile of milk fatty acids, ruminal fermentation, nitrogen balance, ruminal microbial synthesis and concentration of blood metabolites. 24 Holstein cows will be used, 8 of them fistulated in the rumen, distributed in a Latin square (QL), 6 QL 4x4, in the following treatments: basal diet without supplements (A0); and supplementation of 2 g/kg of DM (A50), 4 g/kg of DM (A100) or 6 g/kg of DM (A150) from a commercial source of dehydrated whole-cell DHA-rich microalgae. The diets will be formulated according to the NRC (2001), in the forage: concentrate ratio of 48:52. Each experimental period will last 21 days, with 14 days of adaptation and 7 days of collection. During the collection period, food supplied and daily leftovers will be sampled. Feces and urine collections will be performed on days 17, 18 and 19 of each period. Milk collections will be carried out on days 15, 16 and 17, and blood samples will be collected on day 16. On day 21, ruminal liquid sampling of cannulated cows will be performed, before morning feeding (T0) and 2, 4, 6, 8, 10, 12, 14 and 16 hours after morning feeding. The data will be analyzed using the PROC MIXED - SAS 9.3. | |