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Quantitative information on the concurrent changes in major rumen microbial functions induced by dietary lipids in relation with the degree of unsaturation of fatty acids is scarce. During a three-period essay (9 days per period), rapeseed (Brassica napus L., RO), sunflower (Helianthus annuus L., SO) and linseed (Linum usitatissimum L., LO) oils at the high level of 80 g/kg dry matter input (DMI) and a control without oil were compared in four 1-L dual outflow fermenters inoculated with bovine rumen microbiota and maintained on a maize silage-based diet. Neither the fermentation medium pH and redox potential nor starch and protein degradabilities were significantly altered. Oil supply significantly decreased butyrate and methane specific productions of to the benefit of propionate and hydrogen specific productions and decreased the microbial protein outflow and synthesis efficiency while increasing the outflows of ammonia and isovalerate, these effects being amplified by the fatty acids’ unsaturation degree. Besides, with no impact of the degree of unsaturation, oil supply increased the amount of fermented hexose, the productions of all SCFAs except butyrate and the specific production of acetate. The rumen variables apparently sensitive to oil unsaturation degree were thus related either to metabolic hydrogen removal pathways or to protein metabolism.

The objective of this work was to evaluate the effect of the supplementation of conjugated linoleic acid (CLA; 4.5 g of cis-9,trans-11 C18:2 and 4.5 g of trans-10,cis-12 C18:2) on milk performance, milk fatty acid (FA) composition, and adipose tissue reactivity in dairy goats fed a high-concentrate diet based on corn silage. Twenty-four multiparous dairy goats in early to mid lactation were used in a 10-wk trial, with a 3-wk adaptation to the experimental total mixed ration that contained corn silage (35%, dry matter basis), beet pulp (20%), barley (15%), and a commercial concentrate (30%). Goats were randomly allocated to 2 experimental groups and they were fed 45 g/d of a lipid supplement (either CLA or Ca salts of palm oil added on top of the total mixed ration). Individual milk production and composition were recorded weekly, and milk FA composition was analyzed in wk 2, 5, and 6. In the last week of the trial, an isoproterenol challenge was performed for 12 goats before morning feeding. The CLA supplementation had no effect on dry matter intake (DMI), body weight (BW), milk yield, milk protein content, and lactose yield and content, but it significantly decreased milk fat yield and content by 18 and 15%, respectively. The decrease in milk fat yield was related to a lower secretion of FA synthesized de novo, of the medium-chain FA, and to a lesser extent of the long-chain FA that are taken up from the peripheral circulation. The CLA supplementation decreased the proportion of the sum of C16:0 and C16:1 and the sum of total cis C18:1, and it increased the proportions of the sum of long-chain (C >16) and the sum of iso FA without modification of the total trans C18:1 and the sum of FA synthesized de novo (C

WOS:000393538500020; International audience; Embryo transfer between breeds of different sizes impacts fetal growth in horses. We have shown that it elicits various postnatal adaptations in terms of growth and glucose metabolism until weaning. Postweaning effects remain to be described. Pony (P), saddlebred (S), and draft (D) horses were used. Control Pony-in-Pony (P-P; n = 21) and Saddlebred-in-Saddlebred (S-S; n = 28) pregnancies were obtained by artificial insemination. Enhanced and restricted pregnancies were obtained by transferring P or S embryos into D mares (Pony-in-Draft [P-D], n = 6 and Saddlebred-in-Draft [S-D], n = 8) and S embryos into P mares (Saddlebred-in-Pony n = 6), respectively. Control and experimental foals were raised by their dams and recipient mothers, respectively and weaned on day 180. Weight gain, growth hormones, and glucose metabolism were investigated in foals between days 180 and 540. Pony-in-Draft (P-D) remained heavier than P-P on days 180, 360, and 540, with lower glucose and higher non-esterified fatty-acids on days 180, 360, and 540 and higher T-3 on day 180. Insulin sensitivity was similar between pony groups on days 200 and 540. S-P were lighter than S-D on day 180 but caught up by day 540. S-P had higher glucose than S-D on days 180, 360, and 540, as well as lower non-esterified fatty acids and higher T3 on day 180. Insulin sensitivity was higher in S-P than in S-D on day 200. No difference was observed between saddlebred groups thereafter. In conclusion, in horses, fetal growth is determinant for postnatal metabolism, especially for energy availability. (C) 2016 Elsevier Inc. All rights reserved.

Previous evaluation of milk and meat from clone cattle compared with AI control cows indicated that these products were in the normal range of data, but slight differences were observed in their fatty acid (FA) composition and muscle Δ9-desaturase indexes (Heyman et al. 2007 Animal 1, 936-972). It was therefore hypothesized that epigenic modifications induced by the nuclear transfer technology may affect the expression of the 2 genes [stearoyl-coenzyme A desaturase (SCD)-1, SCD5] responsible for Δ9-desaturation in bovines. The aim of the present experiment was to analyze the differences between clones and controls on FA composition and on SCD1 and SCD5 gene expression of the semitendinosus (ST) muscle. Biopsies of ST were taken from 5 clones from 2 different Holstein genotypes and 5 Holstein AI controls at 26 months of age. Each sample was immediately split into 3 aliquots, frozen in liquid nitrogen, and stored at -80°C until analysis. Fatty acid composition was analyzed by gas chromatography after lipid extraction and methylation according to Bas et al. (2005 Meat Sci. 71, 317-326). Total RNA was isolated from 300 mg of muscle tissue and abundance of SCD1 and SCD5 genes transcripts was determined by RT-PCRas described by Bernard et al. (2005 J. Dairy Sci. 88, 1478-1489) and Lengi and Corl (2007 Lipids 42, 499-508). Results are expressed as percentage of total FA for the FA composition and mRNA abundance of SCD1 and SCD5 determined as relative to the abundance of cyclophilin A mRNA. Statistical analyses were performed using the GLM procedure of SAS (SAS Institute, Cary, NC). Single degree of freedom orthogonal contrasts were used to compare effects of cloning (AI controls v. clones) as well as effects of clone genotypes (genotype 1 v. genotype 2). The C14:0, C14:1 cis-9, C16:0, C16:1 cis-9, and C18:0 proportions in ST were not different between clones and controls. However, clones tended to have a lower proportion of C18:1 n - 9 (-3.1% of total FA; P < 0.07) and higher proportions of C18:2 n - 6 (+1.2% of total FA; P < 0.01), C18:3 n - 3 (+0.7% of total FA; P < 0.05) and n - 3 polyunsaturated FA (+1.17% of total FA; P < 0.05) than controls. Ratios of C14 and C16 Δ9-desaturation in ST were not different between clones and controls but a lower C18 Δ9-desaturation ratio for the clones compared with controls was observed (0.76 v. 0.79; P < 0.05). The mRNA abundance of SCD1 was lower in clone compared with control cows (3.8 v. 8.5; P < 0.05), which could be explained by the higher proportion of n - 3 polyunsaturated FA observed in clones because of the negative effects of these polyunsaturated FA on SCD gene expression. The only difference observed between genotypes was for the C18:0 proportion in muscle (P < 0.05). In conclusion, in our set of animals, cloning decreased the ST muscle gene expression of SCD1 but not of SCD5, which is related to a slight decrease in C18 Δ9-desaturation ratio.