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Effects of trans-10, cis-12 conjugated linoleic acid on ovine milk fat synthesis and cheese properties.
J Dairy Sci. 2007 Jul; 90(7):3326-35.JD

Abstract

Trans-10, cis-12 conjugated linoleic acid (CLA) reduces milk fat synthesis in sheep in a manner similar to that seen in dairy cows, but its effects on cheese yield and flavor are unknown. Additionally, when dietary energy supply is restricted, CLA can increase milk and milk protein yield, which may alter cheese yield and eating quality. The objectives of the study were to examine the effects of supplementing ewe diets with a rumen-protected source of CLA at a high and low dietary energy intake on milk fat and protein synthesis and on cheese yield and eating quality. Sixteen multiparous ewes were randomly allocated to 1 of 4 dietary treatments: a high (6.7 Mcal of metabolizable energy/d) or low (5.0 Mcal of metabolizable energy/d) feeding level that was either unsupplemented or supplemented with 25 g/d of a lipid-encapsulated CLA (to provide 2.4 g/d of CLA) in each of 4 periods of 21 d duration in a 4 x 4 Latin square design. There was no effect of treatment on milk yield (g/d), but milk fat percentage and milk fat yield were reduced by 23 and 20%, respectively, in ewes supplemented with CLA. Milk fatty acid concentration (g/100 g) of chain length < C16 was decreased and > C16 was increased in milk and cheese following CLA supplementation, whereas decreasing the feeding level increased fatty acids > or = C16. Milk fat contents of CLA were 0.01 and 0.12 g/100 g of fatty acids for the unsupplemented and CLA-supplemented treatments, respectively, whereas cis-9, trans-11 CLA was unaffected by CLA supplementation. There was no main effect of treatment on cheese yield, which was 0.11 +/- 0.001 kg of cheese/kg of milk, but cheese yield was highest, at 0.12 +/- 0.001 kg/kg, when made from milk of ewes fed the high feeding level + unsupplemented treatment. Cheese made from the milk of ewes supplemented with CLA, compared with the unsupplemented diet, was rated (scale 0 to 10) higher in the creaminess (2.1 vs. 1.4; SEM 0.15) and less oily (0.8 vs. 1.3; SEM 0.17) attributes, and was preferred overall (4.5 vs. 3.9; SEM 0.21). Cheese produced from sheep on the high vs. low feed level was rated less yellow (2.8 vs. 4.2; SEM 0.11), less salty (1.9 vs. 2.3; SEM 0.15), and more sour (1.5 vs. 1.1; SEM 0.13). We concluded that the effect of feeding level on animal performance and cheese characteristics was small, whereas supplementing the diets of ewes with a ruminally protected CLA source reduced milk fat yield, did not affect cheese yield, and beneficially altered the flavor characteristics of the cheese.

Authors+Show Affiliations

Animal Science Research Centre, Harper Adams University College, Edgmond, Newport, Shropshire, TF10 8NB, United Kingdom. lsinclair@harper-adams.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

17582118

Citation

Sinclair, L A., et al. "Effects of Trans-10, Cis-12 Conjugated Linoleic Acid On Ovine Milk Fat Synthesis and Cheese Properties." Journal of Dairy Science, vol. 90, no. 7, 2007, pp. 3326-35.
Sinclair LA, Lock AL, Early R, et al. Effects of trans-10, cis-12 conjugated linoleic acid on ovine milk fat synthesis and cheese properties. J Dairy Sci. 2007;90(7):3326-35.
Sinclair, L. A., Lock, A. L., Early, R., & Bauman, D. E. (2007). Effects of trans-10, cis-12 conjugated linoleic acid on ovine milk fat synthesis and cheese properties. Journal of Dairy Science, 90(7), 3326-35.
Sinclair LA, et al. Effects of Trans-10, Cis-12 Conjugated Linoleic Acid On Ovine Milk Fat Synthesis and Cheese Properties. J Dairy Sci. 2007;90(7):3326-35. PubMed PMID: 17582118.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of trans-10, cis-12 conjugated linoleic acid on ovine milk fat synthesis and cheese properties. AU - Sinclair,L A, AU - Lock,A L, AU - Early,R, AU - Bauman,D E, PY - 2007/6/22/pubmed PY - 2007/12/6/medline PY - 2007/6/22/entrez SP - 3326 EP - 35 JF - Journal of dairy science JO - J Dairy Sci VL - 90 IS - 7 N2 - Trans-10, cis-12 conjugated linoleic acid (CLA) reduces milk fat synthesis in sheep in a manner similar to that seen in dairy cows, but its effects on cheese yield and flavor are unknown. Additionally, when dietary energy supply is restricted, CLA can increase milk and milk protein yield, which may alter cheese yield and eating quality. The objectives of the study were to examine the effects of supplementing ewe diets with a rumen-protected source of CLA at a high and low dietary energy intake on milk fat and protein synthesis and on cheese yield and eating quality. Sixteen multiparous ewes were randomly allocated to 1 of 4 dietary treatments: a high (6.7 Mcal of metabolizable energy/d) or low (5.0 Mcal of metabolizable energy/d) feeding level that was either unsupplemented or supplemented with 25 g/d of a lipid-encapsulated CLA (to provide 2.4 g/d of CLA) in each of 4 periods of 21 d duration in a 4 x 4 Latin square design. There was no effect of treatment on milk yield (g/d), but milk fat percentage and milk fat yield were reduced by 23 and 20%, respectively, in ewes supplemented with CLA. Milk fatty acid concentration (g/100 g) of chain length < C16 was decreased and > C16 was increased in milk and cheese following CLA supplementation, whereas decreasing the feeding level increased fatty acids > or = C16. Milk fat contents of CLA were 0.01 and 0.12 g/100 g of fatty acids for the unsupplemented and CLA-supplemented treatments, respectively, whereas cis-9, trans-11 CLA was unaffected by CLA supplementation. There was no main effect of treatment on cheese yield, which was 0.11 +/- 0.001 kg of cheese/kg of milk, but cheese yield was highest, at 0.12 +/- 0.001 kg/kg, when made from milk of ewes fed the high feeding level + unsupplemented treatment. Cheese made from the milk of ewes supplemented with CLA, compared with the unsupplemented diet, was rated (scale 0 to 10) higher in the creaminess (2.1 vs. 1.4; SEM 0.15) and less oily (0.8 vs. 1.3; SEM 0.17) attributes, and was preferred overall (4.5 vs. 3.9; SEM 0.21). Cheese produced from sheep on the high vs. low feed level was rated less yellow (2.8 vs. 4.2; SEM 0.11), less salty (1.9 vs. 2.3; SEM 0.15), and more sour (1.5 vs. 1.1; SEM 0.13). We concluded that the effect of feeding level on animal performance and cheese characteristics was small, whereas supplementing the diets of ewes with a ruminally protected CLA source reduced milk fat yield, did not affect cheese yield, and beneficially altered the flavor characteristics of the cheese. SN - 1525-3198 UR - https://www.unboundmedicine.com/medline/citation/17582118/Effects_of_trans_10_cis_12_conjugated_linoleic_acid_on_ovine_milk_fat_synthesis_and_cheese_properties_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-0302(07)71784-8 DB - PRIME DP - Unbound Medicine ER -