Plasma and milk metabolomics in lactating sheep divergent for feed efficiency.

Enhancing the ability of animals to convert feed into meat or milk by optimizing feed efficiency (FE) has become a priority in livestock research. Although untargeted metabolomics is increasingly used in this field and may improve our understanding of FE, no information in this regard is available in dairy ewes. This study was conducted to (1) discriminate sheep divergent for FE and (2) provide insights into the physiological mechanisms contributing to FE through high-throughput metabolomics.

Elucidating genes and gene networks linked to individual susceptibility to milk fat depression in dairy goats.

Dietary supplementation with marine lipids modulates ruminant milk composition toward a healthier fatty acid profile for consumers, but it also causes milk fat depression (MFD). Because the dairy goat industry is mainly oriented toward cheese manufacturing, MFD can elicit economic losses. There is large individual variation in animal susceptibility with goats more (RESPO+) or less (RESPO-) responsive to diet-induced MFD.

Susceptibility to milk fat depression in dairy sheep and goats: Individual variation in ruminal fermentation and biohydrogenation.

Small ruminants are susceptible to milk fat depression (MFD) induced by marine lipid supplementation. However, as observed in dairy cows, there is wide individual variation in the response to MFD-inducing diets, which may be due to individual differences in ruminal processes. Therefore, we compared the ruminal responses of goats and sheep with varying degrees of MFD extent to improve our understanding of this complex syndrome.

Insects as alternative feed for ruminants: comparison of protein evaluation methods.

Background: The high dependence of intensive ruminant production on soybean meal and the environmental impact of this crop encourage the search for alternative protein-rich feeds. The use of insects seems promising, but the extent of their ruminal protein degradation is largely unknown. This parameter has major influence not only on N utilization efficiency but also on the environmental burden of ruminant farming.

Effect of Dietary Supplementation with Lipids of Different Unsaturation Degree on Feed Efficiency and Milk Fatty Acid Profile in Dairy Sheep.

Lipids of different unsaturation degree were added to dairy ewe diet to test the hypothesis that unsaturated oils would modulate milk fatty acid (FA) profile without impairing or even improving feed efficiency. To this aim, we examined milk FA profile and efficiency metrics (feed conversion ratio (FCR), energy conversion ratio (ECR), residual feed intake (RFI), and residual energy intake (REI)) in 40 lactating ewes fed a diet with no lipid supplementation (Control) or supplemented with 3 fats rich in saturated, monounsaturated and polyunsaturated FA (i.e.

Individual differences in responsiveness to diet-induced milk fat depression in dairy sheep and goats.

Both sheep and goats can display very different individual degrees of milk fat depression (MFD), which might explain some apparent contradictions in the literature. Because the antilipogenic effect of certain fatty acids (FA) is the most likely origin of MFD, characterizing the milk FA profile of animals showing different degrees of MFD seems a helpful step to understand the physiological basis of the tolerance or susceptibility to the syndrome. Analyzing whether specific traits may predetermine a particular responsiveness would also be of relevance to meet this aim.

Determination of Cyclopropenoid Fatty Acids in Ewe Milk Fat by GC-MS after Intravenous Administration of Sterculic Acid.

Cyclopropenoid fatty acids (CPEFA), found in oilseeds from Malvaceae and Sterculiaceae, have been shown to interfere with the endogenous synthesis of several bioactive lipids of dairy fat, such as -9, -11 18:2 and -9 18:1, by inhibiting Δ9-desaturase. No previous study has reported the presence of sterculic acid in animal fat and its incorporation in tissues after its administration, due to the lack of a proper methodology. In the present research, a GC-MS method based on cold base derivatization to fatty acids methylesters was developed to determine CPEFA in ewe milk triglycerides, after infusing sterculic acid (0.

Conjugated linoleic acid (CLA)-induced milk fat depression: application of RNA-Seq technology to elucidate mammary gene regulation in dairy ewes.

Milk fat depression (MFD) is characterized by a reduction in the content of milk fat, presumably caused by the anti-lipogenic effects of rumen biohydrogenation intermediates, such as trans-10 cis-12 conjugated linoleic acid (CLA). In this study, RNA-Seq technology was used to help elucidate the mammary responses involved in CLA-induced MFD in lactating ewes. To this end, we compared the milk somatic cell transcriptome of ewes suffering from CLA-induced MFD with control ewes (i.

Conditions Associated with Marine Lipid-Induced Milk Fat Depression in Sheep Cause Shifts in the In Vitro Ruminal Metabolism of 1-C Oleic Acid.

Shifts in ruminal oleic acid (OA) metabolism have received little research attention but recent studies have suggested their association with marine lipid-induced milk fat depression (MFD) in ewes and cows. Measurement of specific products of OA within the complex mixture of digesta lipids is however challenging. Therefore, this in vitro trial combined the isotopic labelling technique with the use of rumen inoculum from cannulated sheep fed a diet supplemented or not with 2% of fish oil (which has been demonstrated to cause MFD in dairy ruminants) to characterize the metabolism of OA in response to ruminal alterations associated with MFD.

Elucidating fish oil-induced milk fat depression in dairy sheep: Milk somatic cell transcriptome analysis.

In this study, RNA sequencing was used to obtain a comprehensive profile of the transcriptomic changes occurring in the mammary gland of lactating sheep suffering from fish oil-induced milk fat depression (FO-MFD). The milk somatic cell transcriptome analysis of four control and four FO-MFD ewes generated an average of 42 million paired-end reads per sample. In both conditions, less than 220 genes constitute approximately 89% of the total counts.

Synthesis of the suspected trans-11,cis-13 conjugated linoleic acid isomer in ruminant mammary tissue by FADS3-catalyzed Δ13-desaturation of vaccenic acid.

The octadecadienoic conjugated linoleic acid (CLA) isomer with trans-11 and cis-13 double bonds (trans-11,cis-13 CLA) has been described in ruminant milk. For now, this specific CLA is suspected to derive exclusively from ruminal biohydrogenation of dietary α-linolenic acid. However, in rodents, the fatty acid desaturase 3 (FADS3) gene was recently shown to code for an enzyme able to catalyze the unexpected Δ13-desaturation of vaccenic acid, producing a Δ11,13-CLA with all the structural characteristics of the trans-11,cis-13 isomer, although no commercial standard exists for complete conclusive identification.