Uso da linhaça na alimentação de vacas em lactação: perfil de ácidos graxos do leite com diferentes concentrações de linhaça

• Ano de defesa: 2024
• Autor(a) principal: Borges, Mariana Assis
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Agronomia; UFSM; Programa de Pós-Graduação em Agronegócios; UFSM Palmeira das Missões
• Palavras-chave em Português: Ácido linoleico conjugado; Bio-hidrogenação; Consumo voluntário; Gordura do leite; Ruminação; Biohydrogenation; Conjugated linoleic acid; Milk fat; Rumination; Voluntary intake; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA
• Link de acesso: http://repositorio.ufsm.br/handle/1/33640

Modulating the fatty acid profile of milk fat by increasing the polyunsaturated fatty acids (PUFA) present in the diet of lactating cows provides consumers with a food with nutraceutical properties. Flaxseed (Linum usitatissimum L.) is a lipid source used to feed dairy cows because of its high content of alpha-linolenic acid (C18:3 n-3). The aim was therefore to determine the composition, profile and fatty acid content of the milk of Holstein cows in a semi-confined system, fed different concentrations of linseed in the diet. Eight Holstein cows were used in a double Latin square experimental model. The lactating cows were grouped into two homogeneous 4x4 Latin Squares and distributed simultaneously over four 21-day periods. The treatments were: 1) Annual ryegrass pasture + corn silage + conventional concentrate without the addition of whole linseed (SL); 2) Annual ryegrass pasture + corn silage + conventional concentrate with the addition of 350g of whole linseed (CL 350); 3) Annual ryegrass pasture + corn silage + conventional concentrate with the addition of 750g of whole linseed (CL 750); and 4) Annual ryegrass pasture + corn silage + conventional concentrate with the addition of 1. 050g of whole linseed (CL 750). 050g of whole linseed (CL 1050). The flaxseed concentrations were divided evenly and offered at two feeding times, individually with the diet of each treatment. Milk samples, physiological parameters and blood samples were collected during the last three days of each period and analyzed for chemical composition and fatty acid profile. Milk production and composition showed no difference (P ≤ 0.05) between treatments. The concentration (g/100 g of fatty acids) of CLA C18:2 c9, t11 showed a difference (P ≤ 0.05) between the treatments, with 0.42; 0.47; 0.49; 0.53, respectively, with CL1050 being the treatment with the highest CLA content. The levels of C18:0 also differed, with 9.68; 11.30; 9.95; 11.70, respectively, between the treatments. The concentration of total cholesterol was within the desirable limit, but there was a difference (P ≤ 0.05) between the treatments, with the CL1050 treatment showing the highest level of this blood parameter. The results show an increase in CLA C18:2 c9, t11 in milk fat and changes in total cholesterol levels in cows. In conclusion, the supplementation of different concentrations of whole linseed in the diet of lactating cows increased the levels of C18:2 c9, t11 (CLA) concomitantly with the increase in doses of whole linseed and influenced the levels of C18:0. The fatty acid profile of the blood showed no difference with increasing doses of linseed.