Partially replacing sorghum silage with cactus (<i>Opuntia stricta</i>) cladodes in a soybean oil‐supplemented diet markedly increases <i>trans</i>‐11 18:1, <i>cis</i>‐9, <i>trans</i>‐11 CLA and 18:2 n‐6 contents in cow milk
Marco Antônio Sundfeld da Gama, Talita Almeida de Paula, Antônia Sherlânea Chaves Véras, Sebastião Inocêncio Guido, Cristiano Amâncio Vieira Borges, Rosemar Antoniassi, Fernando César Ferraz Lopes, María Luciana Menezes Wanderley Neves, Marcelo de Andrade Ferreira
Abstract
Abstract Based on low 18:0 contents observed in milk fat of cows fed cactus cladodes (CC), we hypothesized that including Opuntia stricta cladodes in a soybean oil (SO)‐supplemented diet would promote incomplete rumen biohydrogenation of supplemental PUFA, leading to increased trans ‐11 18:1 and cis ‐9, trans ‐11 CLA contents in milk. Twelve Holstein cows were used in a two‐period study: (a) Baseline: all cows received a total mixed ration (TMR) composed of sorghum silage (SS) and a concentrate containing no SO for 14 days; (b) Treatment: cows received one of the following SO‐supplemented diets for 21 days: (1) SS‐TMR: a TMR composed of SS and a SO‐enriched concentrate, (2) CC‐TMR: a TMR containing CC as a partial substitute for SS plus the SO‐enriched concentrate, and (3) CC‐PMR: same diet as in treatment 2, but CC were mixed with the SO‐enriched concentrate and fed as a partial mixed ration (PMR). Both CC diets increased relative abundances of trans ‐11 18:1, cis ‐9, trans ‐11 CLA, and 18:2 n‐6 in milk fat, whereas opposite effects were observed on 18:0 and cis ‐9 18:1. Proportion of 18:2 n‐6 increased, and cis ‐9, trans ‐11 CLA tended to increase with CC‐PMR as compared to CC‐TMR, whereas 18:3 n‐3 was higher with CC‐PMR than with SS‐TMR. Proportions of several odd‐ and branched‐chain fatty acids, certain 18:1 isomers, and trans ‐9, cis ‐11 CLA changed with CC diets, notably with CC‐PMR. Milk yield and intake of most nutrients (except fibre) increased or tended to increase with the CC diets, whereas gross milk composition was unaltered. Stearoyl‐CoA desaturase‐1 index for C18 (SCD 18 ) was higher with CC‐PMR than with SS‐TMR, and milk n‐6:n‐3 FA ratio and apparent transfer of 18:2 n‐6 to milk increased with CC diets. These results indicate that Opuntia stricta cladodes can be a valuable feed ingredient for improving the nutraceutical value of milk fat.