摘要
Background： The current study evaluated the subcutaneous fatty acid （FA） composition of calf- and yearling-fed steer with or without growth promoting implants. Crossbred steers （n = 112; 267 ± 5.0 kg） of the same contemporary group were allocated to one of four production system and implant strategy based treatments in a completely randomized design with a 2 × 2 factorial arrangement of treatments. Results： There were no interactions （P 〉 0.05） between production systems and growth promoting implants for the total and individual subcutaneous FA. Yearling as opposed to calf finishing reduced （P 〈 0.05） subcutaneous proportions of C20：3n-6, trans （t）l 2-18：1, C14：0, several minor cis-monounsaturated FA （c-MUFA; c9-14：1, c11-16：1, cl 1-18：1, cl 2-18：1, cl 3-18：1, c9-20：1 and cl 1-20：1）, and increased （P 〈 0.05） subcutaneous proportions of tl 1 cl 5-18：2, total and individual branched-chain FA. Subcutaneous fat from steers implanted with growth promotants had higher （P 〈 0.05） proportions of total polyunsaturated FA （PUFA）, total n-6 PUFA, C18：2n-6 and individual t-18：1 isomers （t6 to tl0） compared to non-implanted steers. Conclusions： Overall, current findings show that production systems and growth promotants led to only minor differences in subcutaneous FA composition of beef steers.
Background： The current study evaluated the subcutaneous fatty acid （FA） composition of calf- and yearling-fed steer with or without growth promoting implants. Crossbred steers （n = 112; 267 ± 5.0 kg） of the same contemporary group were allocated to one of four production system and implant strategy based treatments in a completely randomized design with a 2 × 2 factorial arrangement of treatments. Results： There were no interactions （P 〉 0.05） between production systems and growth promoting implants for the total and individual subcutaneous FA. Yearling as opposed to calf finishing reduced （P 〈 0.05） subcutaneous proportions of C20：3n-6, trans （t）l 2-18：1, C14：0, several minor cis-monounsaturated FA （c-MUFA; c9-14：1, c11-16：1, cl 1-18：1, cl 2-18：1, cl 3-18：1, c9-20：1 and cl 1-20：1）, and increased （P 〈 0.05） subcutaneous proportions of tl 1 cl 5-18：2, total and individual branched-chain FA. Subcutaneous fat from steers implanted with growth promotants had higher （P 〈 0.05） proportions of total polyunsaturated FA （PUFA）, total n-6 PUFA, C18：2n-6 and individual t-18：1 isomers （t6 to tl0） compared to non-implanted steers. Conclusions： Overall, current findings show that production systems and growth promotants led to only minor differences in subcutaneous FA composition of beef steers.
基金
funding support from Alberta Livestock and Meat Agency Ltd.
the receipt of NSERC fellowships funded through Alberta Meat and Livestock Agency (ALMA)
