PS2-23. Lipid Profiling of Cattle Treated with the Natural Additive Fator P and Infested with the Parasite Rhipicephalus Microplus.

Abstract In modern livestock farming, the application of technological solutions allows for increased sustainable productivity throughout the production chain. Despite many advances, the ectoparasite R. microplus is an obstacle for cattle farming and causes huge losses to herds. The metabolism of lipid mediators is known to differ significantly between genetically tick-resistant and -susceptible breeds of bovines. In this context, the development of natural additives has become a strategic adjuvant for strengthening animal immunity and may increase resistance to this parasite. The additive Fator P was developed as a performance enhancer, enteric methane reducer, and has shown potential to modulate the host's immune system, increase the concentration and affinity of antibodies against salivary antigens of R. microplus, and reduce tick loads in treated animals. We evaluated the lipidome in animals treated or not with Fator P. Sixteen castrated Holstein bulls, aged between 18 and 20 months, were used, divided into 2 groups and randomized based on weight, body condition score and paternity, between August to December 2024. The treated group received the Fator P additive at a dose of 6.0 g/animal/day, and both groups received a diet composed of corn silage and concentrate at a rate of 2.2% dry matter per kilogram of body weight. Animals in both groups were infested with 15,000 larvae (3x 5.000) on days 38, 40, and 42, and repeated on days 94, 96, and 98 after the start of treatment. Serum samples were collected on day 119 after the start of treatment. The lipidome was analyzed by ultra-performance liquid chromatography coupled to high-resolution mass spectrometry, and data analysis was performed using MetaboAnalyst 6.0 software. A total of 751 different lipids were found in the serum lipidome of the animals. Of these, 29 abundant lipids were observed (Volcano plot analysis p < 0.05; fold change >1.5), with 21 major lipids in the serum of animals treated with Fator P and only 8 major lipids in the serum of control animals. Among the lipids identified, 7 different metabolic pathways were revealed in the animals treated with the additive, namely: arachidonic acid metabolism (p < 0.001), unsaturated fatty acid biosynthesis (p < 0.001), glycerophospholipid metabolism (p < 0.006), glycosylphosphatidylinositol anchor biosynthesis (p < 0.012), linoleic acid metabolism (p < 0.039), alpha-linolenic acid metabolism (p < 0.039), and steroid hormone biosynthesis (p < 0.043). Counts of engorged female ticks were significantly (p = 0.0024) lower in yearlings treated with Fator P relative to untreated controls. The results show that the inclusion of the Fator P in the animals' diet altered the lipidomic profile and acted on the main lipid pathways of the immune system. We propose that Fator P is a metabolic immunomodulator that increases resistance of cattle to R. microplus ticks and it should be used to control infestation.