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J Dairy Sci

Title:		Comparison of the nutritional regulation of milk fat secretion and composition in cows and goats
Author(s):		Toral PG; Chilliard Y; Rouel J; Leskinen H; Shingfield KJ; Bernard L;
Address:		"INRA, UMR1213 Herbivores, F-63122 Saint-Genes-Champanelle, France; Clermont Universite, VetAgro Sup, UMR Herbivores, BP 10448, F-63000, Clermont-Ferrand, France. Natural Resources Institute Finland (Luke), Green Technology, Nutritional Physiology FI-31600, Jokioinen, Finland. Natural Resources Institute Finland (Luke), Green Technology, Nutritional Physiology FI-31600, Jokioinen, Finland; Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FL, United Kingdom. INRA, UMR1213 Herbivores, F-63122 Saint-Genes-Champanelle, France; Clermont Universite, VetAgro Sup, UMR Herbivores, BP 10448, F-63000, Clermont-Ferrand, France. Electronic address: laurence.bernard@clermont.inra.fr"
Journal Title:		J Dairy Sci
Year:		2015
Volume:		20150729
Issue:		10
Page Number:		7277 - 7297
DOI:		10.3168/jds.2015-9649
ISSN/ISBN:		1525-3198 (Electronic) 0022-0302 (Linking)
Abstract:		"A study with 2 ruminant species (goats and cows) with inherent differences in lipid metabolism was performed to test the hypothesis that milk fat depression (MFD) due to marine lipid supplements or diets containing high amounts of starch and plant oil is caused by different mechanisms and that each ruminant species responds differently. Cows and goats were allocated to 1 of 3 groups (4 cows and 5 goats per group) and fed diets containing no additional oil (control) or supplemented with fish oil (FO) or sunflower oil and wheat starch (SOS) according to a 3 x 3 Latin square design with 26-d experimental periods. In cows, milk fat content was lowered by FO and SOS (-31%), whereas only FO decreased milk fat content in goats (-21%) compared with the control. Furthermore, FO and SOS decreased milk fat yield in cows, but not in goats. In both species, FO and SOS decreased the secretion of C16 FA output. However, SOS increased milk secretion of >C16 FA in goats. Compared with the control, SOS resulted in similar increases in milk trans-10,cis-12 conjugated linoleic acid (CLA) in both species, but caused a 2-fold larger increase in trans-10 18:1 concentration in cows than for goats. Relative to the control, responses to FO in both species were characterized by a marked decrease in milk concentration of 18:0 (-74%) and cis-9 18:1 (-62%), together with a ~5-fold increase in total trans 18:1, but the proportionate changes in trans-10 18:1 were lower for goats. Direct comparison of animal performance and milk FA responses to FO and SOS treatments demonstrated interspecies differences in mammary lipogenesis, suggesting a lower sensitivity to the inhibitory effects of trans-10,cis-12 CLA in goats and that ruminal biohydrogenation pathways are more stable and less prone to diet-induced shifts toward the formation of trans-10-containing intermediates in goats compared with cows. Even though a direct cause and effect could not be established, results suggest that regulation of milk fat synthesis during FO-induced MFD may be related to a shortage of 18:0 for endogenous mammary cis-9 18:1 synthesis, increase in the incorporation of trans FA in milk triacylglycerols, and limitations in the synthesis of FA de novo to maintain milk fat melting point. However, the possible contribution of biohydrogenation intermediates with putative antilipogenic effects in the mammary gland, including trans-9,cis-11 CLA, trans-10 18:1, or cis-11 18:1 to FO-induced MFD cannot be excluded"
Keywords:		"Animals Cattle/*physiology Diet/veterinary *Dietary Supplements Fatty Acids/*analysis/metabolism Female Fish Oils/*administration & dosage Goats/*physiology Lactation Linoleic Acids, Conjugated/analysis/metabolism Lipid Metabolism Milk/*chemistry/metaboli;"
Notes:		"MedlineToral, P G Chilliard, Y Rouel, J Leskinen, H Shingfield, K J Bernard, L eng Comparative Study Research Support, Non-U.S. Gov't 2015/08/04 J Dairy Sci. 2015 Oct; 98(10):7277-97. doi: 10.3168/jds.2015-9649. Epub 2015 Jul 29"