Parâmetros nutricionais, composição e perfil de ácidos graxos do leite de cabras alimentadas com líquido da casca da castanha do caju

Abstract

The aim was to evaluate the effects of increasing levels of cashew nutshell liquid (CNSL) inclusion in the diet of dairy goats on animal performance, milk yield, and goat milk quality. A total of eight Saanen goats in their second to third lactation, with an average body weight (BW) of 54.30 ± 9.45 kg and an average milk yield of 2.41 ± 0.56 kg/day, were used. The animals were allocated in a 4 × 4 double Latin square design. The experimental diets consisted of a control diet (T1) with no CNSL inclusion (g/kg dry matter [DM]) and diets with the inclusion of 5 g (T2), 15 g (T3), and 20 g (T4) of CNSL per kg of DM. The intake of DM (DMI, kg/day; %BW; g/kg0.75 BW), organic matter (OMI), crude protein (CPI, kg/day; %BW; g/kg0.75 BW), neutral detergent fiber (NDFI, kg/day; %BW; g/kg0.75 BW), total carbohydrates (TCI), and nonfibrous carbohydrates (NFCI), as well as digestible energy (DEI, P = 0.750), metabolizable energy (MEI, P = 0.749), and net energy for lactation (NELI, P = 0.805) expressed in Mcal/kg of DM, and nutrient digestibility coefficients, were not influenced (P > 0.05) by CNSL inclusion. However, ether extract intake (EEI) increased linearly (P < 0.001) with CNSL inclusion. The absorption of purine derivatives (PDA), total purine excretion (TPE, mmol/day), and microbial crude protein synthesis (MCPS, g/day) exhibited a quadratic response to increasing CNSL levels. Milk composition was not affected (P > 0.05) by CNSL inclusion, although milk urea nitrogen (MUN, mg/dL) showed a linear response (P < 0.001). Fatty acids such as C15:0 (P = 0.021), C17:0 (P = 0.029), C18:0 (P = 0.045), C18:1-trans 9 (P = 0.001), and C18:3-n3 (P = 0.007), along with the partial sum of omega-3 fatty acids (Σn3) and the PUFA/SFA, n6:n3, n3:n6, and PUFA/MUFA ratios, exhibited a linear increase (P < 0.05) with CNSL inclusion. Therefore, cashew nutshell liquid emerges as a promising strategy, acting as an effective feed additive for dairy goats, aiming to enhance the concentration of bioactive fatty acids in milk and improve its nutritional benefits. The results support the hypothesis that CNSL inclusion in dairy ruminant diets can beneficially alter milk lipid profile for human health without compromising nutritional variables.