Fatty Acids, lipolysis and goat flavour (1) Specificities of lipid metabolim in goats :

Transcription

1 Specificities of lipid metabolim in goats : Yves Chilliard INRA Clermont-Ferrand / Theix France - milk FA profile (high C8 & C1, and B-CFA) - lipolytic system (LPL regulations; flavour) (e.g. Chilliard et al, 23; Eknaes, 29) (Milk quality and lactation physiology of dairy goats Seminar 31 May 21 UMB, NULS, Norway) Fatty Acids, lipolysis and goat flavour (1) Fat globule triglycerides Specificities of lipid metabolim in goats : - high % C6-C1 FA, mostly on carbon 3 - methyl / ethyl C8 (.3 g/kg fat) (1) Chilliard et al (23) Lipoprotein lipase - high % bound to cream - correlated to lipolysis - release of FA from carbon 1-3 Free methyl / ethyl C8 Goat flavour - milk FA profile (high C8 & C1, and B-CFA) - lipolytic system (LPL regulations; flavour) -geneticpolymorphism(as1-casein/lipids) - responses to lipid feeding (no MFD, high CLA, low lipolysis, ) (e.g. Chilliard et al, 23-27; Eknaes et al, 26-29) 1

2 Characteristics of diets that cause milk fat depression Trans fatty acids and mammary lipogenesis in ruminants KJ Shingfield, L Bernard, C Leroux and Y Chilliard 1) High concentrate/low fibre diets 2) Rations containing marine lipids 3) Diets containing ionophores Addition of polyunsaturated fatty acids (published in ANIMAL, 21, vol 4, pages ) Changes in rumen biohydrogenation Characteristic changes in ruminal biohydrogenation Relationship between post-ruminal infusions of trans-1, cis-12 CLA and milk fat yield cis-9, cis-12 C 18:2 (linoleic acid) cis-9, trans-11 C 18:2 (CLA) trans-11 C 18:1 (vaccenic acid) C 18: (stearic acid) Diet induced trans-1, cis-12 C 18:2 (CLA) trans-1 C 18:1 C 18: (stearic acid) trans-1 shift Inhibition (Shingfield ISRP29, from Griinari and Bauman, 1999) Change in milk fat yield (%) Y = exp x r 2 = Amount of trans-1, cis-12 CLA infused (g/d) (Shingfield ISRP29, from De Veth et al., 24) 2

3 Does trans-1, cis-12 CLA explain the decreases in milk fat? Nutritional regulation of mammary lipogenesis in the ovine and caprine Reference Piperova et al., 2 Peterson et al., 23 Bell et al., 26 Roy et al., 26 Milk t1,c12 CLA (g/1 g) Change in milk fat yield (%) Measured Predicted Explained Diets that cause MFD in cows increase milk fat synthesis in goats (Chilliard et al., 27) Limited data suggest that responses in sheep are more comparable to goats than cows (e.g. Mele et al., 26; Hervás et al., 28) Species differences may be due to effects on ruminal biohydrogenation or regulation Mean 34.5 of mammary lipogenesis (Shingfield et al, ISRP 29) (Shingfield et al, ISRP 29) Relationship between mammary lipogenesis and milk trans-1 18:1 in the bovine Relationship between mammary lipogenesis and milk trans-1 18:1 in the caprine 5. Percentage change in milk fat yield Increase in milk trans-1 18:1 content [g/1 g fatty acids] y = exp x r 2 =.676, No. = 82, P <.1 Percentage change in milk fat yield No obvious relationship Increase in milk trans-1 18:1 content [g/1 g fatty acids] Shingfield et al., unpublished Chilliard et al., unpublished 3

4 Comparison of mammary lipogenesis and milk trans-1 18:1 between ruminant species Increases in milk trans-1 18:1 concentrations are 3-fold higher in cows than goats or sheep Increases in milk trans-1 18:1 are associated with MFD in cows but not in goats or sheep Data suggest that ruminal biohydrogenation is much less susceptible to the trans-1 shift in small ruminants (Shingfield et al, ISRP 29) trans11-18:1 (VA) trans1-18:1 % tot FAs % tot FAs Oil Fiber/18: Oil Starch/18: DAYS (Roy et al, Anim Sci 26) Stability of CLA response in goat milk rumenic acid (% tot FAs) Fiber + 18:3 3 2 Starch + 18: Days after starting oil feeding = control = linseed oil = sunflower oil = 7% forage = 7% concentrate Percentage change in milk fat yield Mammary lipogenic responses in ruminants fed rumen-protected CLA Cows Goats Sheep Milk trans-1, cis-12 CLA content [g/1 g fatty acids] (Chilliard et al, EJLST, 27) Shingfield et al., 29 & unpubl. 4

5 Key genes involved in mammary lipogenesis Fat globule Nutritional regulation of mammary lipogenesis in ruminants: molecular dimension de novo Synthesis ACC : Acetyl-CoA carboxylase FAS : Fatty acid Synthase LPL : Lipoprotein-lipase SCD : Stearoyl-CoA desaturase GPAT : Glycerol-3-phosphate acyltransferase AGPAT : Acylglycerol-3 phosphate acyltransferase DGAT : Diacylglycerol acyltransferase Endoplasmic TG reticulum Short/medium chain FA GPAT (C4-C16) AGPAT FAS DGAT + Glycerol-3-P Malonyl-CoA Long chain FA ACC (C16-C22) SCD Acetyl-CoA FA Uptake FA Glycerol LPL Acetate FA Triglycerides Glucose Beta-hydroxybutyrate Albumin (Chylomicrons/VLDL) Mammary epithelial cell blood Regulation may be mediated via transcription, translation, protein turnover and enzyme activity De novo fatty acid synthesis (ACC and FASN) Fatty acid uptake (LPL) Desaturation of fatty acid substrates (SCD) Nutritional regulation of de novo fatty acid synthesis in ruminants Nutritional regulation of mammary long chain fatty acid uptake in ruminants Piperova et al., 2 Ahnadi et al., 22 Baumgard et al., 22 Peterson et al., 23 Harvatine and Bauman, 26 Chilliard et al., 27 Bernard et al., 29 Diets causing MFD or infusion of trans-1, cis-12 CLA 3-59% decrease in C1-C16 secretion in milk Lowered ACC and FASN mrna abundance and activity Starch rich diets supplemented with plant oils 5-32% decrease in C1-C16 secretion in milk No change in ACC and FASN mrna abundance and activity Ahnadi et al., 22 Harvatine and Bauman, 26 Bernard et al., 25a,b Bernard et al., 29a,b Diets causing MFD or infusion of trans-1, cis-12 CLA Decrease in C18 fatty acid secretion in milk Lowered LPL mrna abundance Starch rich diets supplemented with plant oils Increase in C18 fatty acid secretion in milk No change or increase in LPL mrna abundance/activity LPL activity does not appear to limit mammary long-chain fatty acid uptake in the goat but may be a limiting factor during MFD in cows 5

6 Ahnadi et al., 22 Baumgard et al., 22 Bernard et al., 25a,b Bernard et al., 29a,b Nutritional regulation of mammary Δ-9 desaturase (SCD1) in ruminants Varies little in response to diet Diets containing fish oil or infusion of trans-1, cis-12 CLA Lowered SCD1 mrna abundance Varies according to basal diet and composition of lipid supplement Formaldehyde-treated linseeds lower SCD1 mrna abundance Plant oils often decrease SCD1 activity Concluding remarks #1 1. Ruminal production of trans-1, cis-12 CLA, trans- 9, cis-11 CLA and cis-1, trans-12 CLA cannot explain entirely MFD in cows 2. Even in the absence of effects on milk fat synthesis certain trans fatty acids may alter lipogenic gene expression and enzyme activity 3. Effects of trans fatty acids may be mediated at least in part via effects on transcription factors and cellular signalling pathways (Shingfield et al, ISRP29) Concluding remarks #2 Nutritional regulation of the caprine mammary transcriptome 4. Mammary lipogenic responses to changes in diet composition differ between ruminant species 5. Some evidence to suggest that differences between ruminant species are related to the effects of diet on ruminal biohydrogenation 6. Indirect comparisons indicate inherent differences in the sensitivity of mammary lipogenic genes to trans fatty acids between ruminant species (Shingfield et al, ISRP29) HF-RS vs HC-SO vs HF HC (n=16 lactating goats) - lipids Fat content Oleic acid Fat content + yield Total trans FA + lipids HC LF HF HF LF-SO HCSO HF-RS HFRS mean mean mean mean (Ollier et al., JDS, 29) I II III IV V VI VII Transcriptome analyses (8 5 bovine genes microarray -> statistical analyses) Clustering Gene expression profiles highly dependent on diet 6

7 Impact of food-deprivation on mammary function FOOD-DEPRIVATION PROTEIN major milk FAT proteins synthesis de novo short- and medium-chain FA LACTOSE synthesis synthesis Drop in milk production and milk component secretion MAMMARY GENE EXPRESSION MILK protein, lactose, fat yields MAMMARY CELL MACHINERY mrna stabilization MAMMARY CELL LIFE proliferation differentiation programmed cell death First step involution process? (Ollier et al, 27; Leroux et al., 28) LIPGENE Impact of CSN1S1 polymorphism on milk «Reference» CSN1S1 Genotype «Defective» CSN1S1 Genotype AA (Ollier et al., 28) Milk yield (kg/d) AA EF EF AB EF DIET A G R I C U L T U R E C. Leroux et al., 24 th PPS 28 E N V I R O N M E N T Fat yield (g/kg) * * 2 1 * P <,5 Ref Def Ref Def Ref Def Protein yield (g/kg) «Defective» Mammary Epithelial Cell (Ollier et al., 28) Altered biological processes Caseins Micelle Dilated endoplasmic Reticulum Nucleus Fat Globule Alteration of mammary cells function related to CSN1S1 defective alleles 一一 1,3 FASN FA C8-C12 TG GPAM 一 1,4 一 1,3 SCD 一 1,7 一 1,3 UNC119 cell-cell interaction 一 1,5 FA desaturation β-catenin FYN 一 一 1,7 / FER 一 1,3 CSK 一 1,5 一 1,3 TFDP2 POLD3 一 1,3 TLK1 Replication chromatin Reorganisation BAZ2B 一 1,4 Transcription Milk FAs Low High CSN1S1 genotype N. goats (Chilliard et al, 26a) C6: * C8: ** decreases melting point in H Goats C9:.7.8* C1: ** C11:.9.11** C12: ** C16: ** C16:1c ** C17:1.3.27* C18: ** (less desaturated in H goats) C18:1c ** C18:2c9t ** C18:2n ** CLAc9t ** Delta 9-desaturation ratios: (are not related to SCD mrna levels?) C1:1/C ** C14:1/C * C17:1/C * C18:1c9/C ** increases melting point in H Goats CLA/VA.69.55** DIET A G R I C U L T U R E c9t13/t13 C. Leroux et al., 24 th PPS 28 E N V I R O N M E N T.71.59* 7

8 Genotype-Diet (Extr. Linseed) interactions (Chilliard and Rouel, unpubl.) Response of goat milk fatty acids to oil or oilseeds feeding (Chilliard et al, 23) CSN1S1 Genotype High High Low Low Diet Control ELS Control ELS Supplement Linseed (N. goats) Milk fat content (g/kg) (23) (23) (24) (24) Gen*Diet P<,9 Fat content (g/kg) Oil +3.1 Seeds +6. Lipolysis (g OA/1 g fat) C1: (% tot. FAs),4,3 18:2 +18:3 (%) C16: C18: C18:1cis9 C14:1 / (C14:+C14:1) C18:1cis9 / (C18:+C18:1 cis9),2,2,1,2 NS VA + RA (%) Stearic + oleic (%) Goat milk RA & ALA (% total FA) (Chilliard & Ferlay, 24) RA ALA 2 control (hay) diets :.3%.5-.8% 3 hay diets + linseed oil : % % 1 hay diet + extr. linseeds : 2.1% 2.7% Years (Chilliard et al, 26 b and 27) 181 Alpine goats in 19 dietary groups 5 forages : Maize Silage Alfafa Hay Rye-grass Hay Fress Rye-grass Natural grassland Hay 3 lipid supplements (13g/d) during 3-1 weeks : Oleic sunflower oil (C18:1 n-9) Sunflower oil (C18:2 n-6) Linseed oil (C18:3 n-3) Milk from 13 dietary groups used to make cheese by 5 different technologies 8

9 Goat milk saturated FA atherogenic index [% C12: +4 (% C14:) + % C16:] Goat milk fat oleic acid (C18:1, cis 9) In 7 control diets : % In 12 lipid diets : % X.65 In 7 control diets : % In 4 oleic sunflower oil diets : % X 1.69 Goat milk fat linolenic/linoleic ratio (18:3 n-3/18:2 n-6) Goat milk fat rumenic acid equivalent [rumenic acid +.2 vaccenic acid] In 4 maize silage diets, without lipids, or with sunflower or oleic sunflower oil : In 2 maize silage diets with linseed oil : In 4 Hay/Grass diets with linseed oil : X 3.6 X control diets, and 4 oleic sunflower diets : % 6 Linseed oil diets : Sunflower oil diets : % X 4.8 X 6.3 9

10 Goat milk fat non-trans 11 C18:1 and C18:2 trans isomers (i.e. except rumenic and vaccenic acids) 7 control diets : % 8 Hay/Grass diets + oils : Maize Silage diets + oils : X 4.7 X 8.8 Flavour defect occurrence (among 7 criteria) 5 control diets : /7 4 oleic sunflower diets :.5/7 4 linseed oil diets : 1*/7 * small oxidized or fishy flavours Goat flavour in fresh lactic cheese (score -1) 5 control diets : oil supplemented diets : X.89 This decrease was probably due to strong decreases in native milk LPL activity and post-milking lipolysis (x.54) 1