PSX-22 Nannochloropsis oculata microalgae as a natural source of rumen-protected eicosapentaenoic acid in diets of lactating Nubian goats

Abstract Dietary fats can affect lactational performance of goats and modify the profile of fatty acids in milk. The effects of providing lactating Nubian goats with Nannochloropsis oculata microalgae, as a natural source of rumen-protected eicosapentaenoic acid (EPA), on the feed intake, digestion, ruminal fermentation, lactational performance and milk fatty acid profile were evaluated. Fifteen lactating does, weighing 33.0 ± 1.3 kg after parturition, were randomly assigned to three treatments in a quintuplicated 3 × 3 Latin square design. Does were stratified according to their previous milk production, parity and expected average milk yield in a 12-week experiment. Does were fed a basal diet containing 300 g of berseem clover, 200 g wheat straw and 500 g of concentrates (control treatment) or the control diet supplemented with 5 g (NO5 treatment) or 10 g (NO10 treatment) of N. oculata microalgae. Dietary treatments did not affect feed intake but increased (P < 0.01) nutrient digestibility. Without affecting ruminal pH and ammonia-N, NO5 and NO10 treatments linearly increased total volatile fatty acids (P = 0.002) and propionic acid (P = 0.022). Dietary treatments linearly increased (P < 0.01) daily milk production and the concentration of lactose without affecting other milk components. Both NO5 and NO10 treatments decreased atherogenic index (P = 0.004) and increased the concentrations of unsaturated fatty acids and C20:5n3 (EPA). In conclusion, supplementing the diet of lactating Nubian goats with N. oculata microalgae at 5 and 10 g daily enhanced milk production and altered milk fatty acid composition. Although further research is needed, performance responses associated with increasing the dose of the microalgae from 5 g to 10 g /doe were not large; thus, the 5 g dose is recommended for practical use.