Dietary palmitic acid supplementation (PA) in dairy cows affects milk technological properties. In a controlled trial with 8 Holstein cows, we investigated the impact of PA on milk nitrogen fractions, milk fat integrity, and butter properties. We also investigated whether modifying cream ripening conditions could attenuate the impacts of PA on butter hardness. Milk caseins and whey proteins decreased, and non-protein nitrogen concentrations increased with PA. Supplementation with PA also increased milk susceptibility to lipolysis but decreased its sensitivity to oxidation. Butter manufacture from PA-supplemented cows required longer churning, and the resulting butter was harder at room temperature. The cold-warm-cold ripening protocol reduced churning time but had limited capacity to compensate for PA-induced texture modifications, only reducing butter hardness at 4°C.

Palmitic acid (PA) supplementation and greater milking frequency can increase milk production and fat yield in dairy cows. However, the technological effects of those practices on cheesemaking still need to be determined. This work aimed to evaluate, with Holstein dairy cows, the effects of dietary PA, thrice-daily milking frequency, and their interaction on cheese yield and composition. Before cheesemaking, milks were standardized to a casein-to-fat ratio of 0.78% (SE: 0.02) and targets of 3.27% (SE: 0.03) and 4.20% (SE: 0.05). Rennet coagulation properties of standardized milk, cheese composition, curd draining properties, free fatty acid (FFA) content, and proteolysis during ripening were analyzed. Dietary PA supplementation modified the milk fatty acid profile but did not affect coagulation and draining properties, cheese composition, or proteolysis. The moisture-adjusted yield and fat and protein recoveries were also similar between treatments. The greater milking frequency did not affect process performance. However, increasing milking frequency led to a significantly higher FFA content in cheese at the end of ripening of 1.4 (SE: 0.2) mEq/kg versus 0.8 (SE: 0.2) mEq/kg of cheese fat for thrice- and twice-daily milkings, respectively. Consequently, dietary supplementation of PA to dairy cows had only a limited effect on the cheesemaking process under the standardized conditions tested. However, the effects of FFA on cheese sensory properties should be considered if the milking frequency is increased.

Forty meat or dairy kids were blocked within breed according to body weight. Kids within each block were then randomly allotted to a concentrate-based diet or an intensive rotational grazing system. Kids fed the concentrate-based diet were offered hay ad libitum and fixed amounts of whole corn and soybean meal to meet the requirements for maintenance and daily gain. Grazing kids from each breed were stocked in groups and offered a new paddock every day. Dry matter intake was not different between breeds. Meat kids had a greater average daily gain than dairy kids, but feeding treatments did not affect the growth rate. Dairy kids had greater anterior cuts (neck and shoulder), whereas meat kids tended to have greater posterior cuts (loin and leg). Meat kids accumulated more fat when they were fed concentrate in comparison with pasture, whereas this variable tended to be less influenced by dietary treatments in dairy kids. Meat of pasture-fed kids had greater Warner–Bratzler shear force and glycolytic potential, and lower ultimate pH than meat of concentrate-fed kids. The n-6/n-3 fatty acid ratio of intramuscular fat was almost 4-fold greater in concentrate- than pasture-fed kids; this ratio was 1.4-fold greater in dairy than meat kids.

The objective of the current trial was to evaluate the effect of feeding four different forage species on milk yield and composition, including protein and fatty acid profiles, in dairy goats. Two grasses (Timothy; mown at early heading, and Italian ryegrass; mown at 25 cm height) and two legumes (Alfalfa and White clover; both mown at 10% bloom) were harvested and conserved as silage. Twelve dairy goats of three different breeds (4 Alpine, 4 Toggenburg, and 4 Saanen) in late lactation were used in a replicated 4 × 4 Latin square design. Goats were offered ad libitum access to the tested forages supplemented with 180 g/d of concentrates based on rolled barley and heat-treated soybean meal. DM intake was lower with timothy, intermediate with ryegrass and white clover, and greater with alfalfa. Milk yield was lower with timothy as compared with the other three silages. Milk fat yield was similar among treatments. Milk CP yield was lower with timothy as compared with the other three silages. Milk N efficiency (N secreted/N intake) was greater with timothy, intermediate with ryegrass, and lower with the two legume silages. The proportion of true protein as a percentage of CP was lower in milk from goats fed legume as compared with grass silages. Proportions of casein and whey protein expressed as percentages of true protein were greater with timothy, intermediate with ryegrass and white clover, and lower with alfalfa. Among grass silages, intake and milk secretion of cis-9, cis-12 cis-15 18:3 was greater with ryegrass than with timothy. As a result, the transfer efficiency from dietary intake to secretion in milk was not different between these two treatments. Fewer differences were observed regarding legume forages, as cis-9, cis-12, cis-15 18:3 intake and milk secretion were similar with alfalfa and white clover. However, the transfer of cis-9, cis-12, cis-15 18:3 from diet to milk was highest when feeding alfalfa. In conclusion, forage species fed to dairy goats influence milk composition in terms of fatty acids and protein fractions, which can potentially impact the nutritive value and technological properties of milk.

Fatty acids (FA) in follicular fluid (FF) are present in an esterified form [triglycerides, cholesterol esters and phospholipids] or as non-esterified FA, which partly originate from blood. However, a comprehensive comparison of blood vs. FF FA in various lipid classes is missing. The aim of this study was to determine the distribution of the FA composition in each lipid class of serum and FF, and to investigate their mutual correlations. A total of 74 patients undergoing assisted reproductive technology treatment were involved in the study. Both in serum as well as FF, saturated FA and mono-unsaturated FA were predominant in non-esterified FA and triglycerides fractions while poly-unsaturated FA were mainly present in phospholipids and cholesterol esters fractions, although phospholipids also contained high proportions of saturated FA. Irrespective of the lipid class, the FA proportions differed between serum and FF (P < 0.05). Despite these differences, most of the FA in triglycerides, phospholipids and cholesterol esters of FF were well correlated with their proportions in serum. Nevertheless, only weak to moderate associations (r < 0.60) were observed for the majority of the FA in the non-esterified FA fraction. Differences in FA product/precursor-ratios were found between serum and FF, such as higher C20:4n-6 to C18:2n-6 and C20:5n-3 to C18:3n-3 in FF. FA metabolism (e.g. desaturation and elongation) takes place in cells of the intrafollicular micro-environment. Moreover, good correlations between esterified FA in serum and FF suggest esterified FA in blood could be representative of esterified FA in FF.

AbstractTriacylglycerols (TAG) are the primary sources of preformed fatty acids (FA) for lipid synthesis in the mammary gland. However, polyunsaturated FA escaping ruminal biohydrogenation are selectively incorporated into cholesterol esters (CE) and phospholipids (PL). The aim of the current experiment was to study the effects of abomasal infusion of increasing amount of linseed oil (L-oil) on plasma distribution of α-linolenic acid (α-LA) and its transfer efficiency into milk fat. Five rumen-fistulated Holstein cows were randomly distributed in a 5 × 5 Latin square design. Abomasal infusion of L-oil (55.9% α-LA) was performed at the rate of 0, 75, 150, 300, and 600 ml/d. Concentrations of α-LA increased quadratically in TAG, PL, and CE; a less steep slope was observed with an inflexion at an infusion rate of 300 ml L-oil per day. The increase in plasma concentration of α-LA was of a lower magnitude in CE as compared with the other two fractions, resulting in a quadratic decrease in relative proportion of this FA circulating as CE. The transfer efficiency into milk fat increased from 0 to 150 ml L-oil infused, and a plateau was maintained thereafter with greater levels of infusion (quadratic response). This pattern resembles the quadratic response of the relative proportion of α-LA circulating as TAG, and the relative concentration of this FA in TAG. Increasing the postruminal supply of α-LA partly overcame the segregation mechanism of absorbed polyunsaturated FA in different plasma lipid classes. Proportionately more α-LA was then esterified as TAG, at the expense of CE, increasing its efficiency of transfer into milk fat. This mechanism appears to be surpassed in its turn when L-oil infusion was increased over 150 ml/d. Nevertheless, the yield of α-LA in milk fat continued to increase, but at a slower rate at the highest levels of infusion.

The aim of the current trial was to study the impact of a high somatic cell count (SCC) on milk volatilome of fresh raw milk, and its evolution during storage of processed fluid milk. Six Holstein cows were selected from our research dairy herd based on test-day SCC records. Three cows were used to produce low-SCC milk (20 × 103 cells/mL). The three other cows had one-quarter infected by Staphylococcus aureus. Infected and healthy udder halves were milked separately, and high-SCC milk was standardized to 400 × 103 cells/mL by mixing these two milks. The profile of milk volatile organic compounds (VOCs) was determined on raw milk and during the storage of processed milk. The processing included a standardization to 3.25% fat, followed by homogenization, and thermization (65 °C/30 min). This procedure was repeated four times over a period of 7 days. A total of 40 VOC were identified using the solid-phase microextraction technique followed by gas chromatography separation, mass spectrometry analysis, and database search. These VOC were grouped into seven different families, including alcohols (n = 4), free fatty acids (n = 5), sulfur compounds (n = 3), esters (n = 7), ketones (n = 7), aldehydes (n = 12), and aromatic hydrocarbons (n = 2). In raw milk, high SCC was associated with a tendency for lower concentrations of ethyl-hexanoate (P = 0.07), acetone (P = 0.06), and benzaldehyde (P = 0.07) and lower concentrations of trans-2 hexenal (P = 0.04). On the contrary, high SCC was associated with a tendency for greater concentrations of acetic acid (P = 0.09) and hexanoic acid (P = 0.07) and greater concentrations of 2-nonanone (P = 0.02) and pentanal (P = 0.01). Concentrations of most VOC increased during the storage of processed milk. Lower concentrations of butanoic acid (P = 0.09; tendency) and ethyl hexanoate (P = 0.04), and greater concentration of 1-ocen-3-ol (P < 0.01) were observed in high-SCC milk at all times of storage evaluated. Increases in concentrations over time were less pronounced for ethanol (P < 0.01), ethyl butanoate (P = 0.05), and propanal (P = 0.10) in high SCC as compared with low SCC milk. In conclusion, an increase in SCC has a limited effect on milk volatilome, when a SCC standard of 400 × 103 cells/mL for bulk milk is respected.

Twelve multiparous Holstein cows (42.2 ± 5.6 kg of milk/d; 83 ± 27 d in milk) were used in a split-plot design testing the effects of mineral and vitamin supplementation on the time course of animal performance, metabolism, and inflammation markers during heat stress. The main plot was the average concentrations of dietary vitamin E and Se (adequate: 11.1 IU/kg of vitamin E and 0.55 mg/kg of Se, and high: 223 IU/kg of vitamin E and 1.8 mg/kg of Se, respectively). Within each plot, cows were randomly assigned to (1) heat stress (HS) with adequate concentrations of vitamin D3 and Ca (1,012 IU/kg and 0.73%, respectively), (2) HS with high concentrations of vitamin D3 and Ca (HS+D3/Ca; 3,764 IU/kg and 0.97%, respectively), or (3) pair-feeding (PF) in thermoneutrality with adequate concentrations of vitamin D3 and Ca (1,012 IU/kg and 0.73% Ca) in a Latin square design with 14-d periods and 7-d washouts. The highest rectal temperature was recorded at 1700 h for HS (39.4°C; mean of d 1 to 14), being 1.2 and 0.8°C greater than for PF and HS+D3/Ca, respectively. Respiratory rate and water intake were higher in HS (73 breaths/min and 115 L/d, respectively) relative to PF (28 breaths/min and 76 L/d). Heat stress decreased dry matter intake progressively, reaching a nadir on d 5 to 7 (33% reduction) and was not different between treatments. Milk yield decreased progressively in all treatments, but remained greater in PF relative to HS from d 3 to 14 (10%), whereas HS and HS+D3/Ca were not different. Milk fat, protein, and lactose concentrations and yields were lower in HS relative to PF from d 3 to 14, but not different between HS and HS+D3/Ca. Relative to PF, preprandial insulin concentrations were increased in HS, whereas plasma nonesterified fatty acids were decreased on d 7 and 14. Plasma lipopolysaccharide-binding protein concentrations increased in HS cows on d 7 and 14, respectively, relative to PF, whereas they were reduced in HS + D3/Ca on d 14. Plasma C-reactive protein, tumor necrosis factor-α, and fecal calprotectin were increased in HS relative to both PF and HS+D3/Ca on d 7 and 14. Rectal temperature was positively associated with plasma lipopolysaccharide-binding protein (r = 0.72), tumor necrosis factor-α (r = 0.74), C-reactive protein (r = 0.87), and with milk somatic cells (r = 0.75). Plasma 8-hydroxy-2-deoxyguanosine concentrations presented a 3-way interaction, where 8-hydroxy-2-deoxyguanosine was lower in HS than in PF on d 7 and 14, and lower in HS+D3/Ca relative to HS on d 14 in the adequate vitamin E and Se treatment, but no effects were observed in the high vitamin E and Se group. Plasma superoxide dismutase concentrations increased over time, and were higher in HS relative to PF on d 14, whereas HS+D3/Ca was similar to HS. Heat stress markedly reduced milk production and milk components while increasing markers of leaky gut and inflammation. In contrast, vitamin D3 and Ca supplementation reduced hyperthermia (d 7-14), markers of leaky gut, and inflammation independent of dietary concentrations of vitamin E and Se.

One hundred twenty crossbred steers were allotted to six weight blocks. Within each block, steers were allotted to one of four pens in a randomized complete block design (5 head per pen, 24 total pens). Treatments were low forage control diets (LFC) or high forage diets supplemented with soybean oil (HFO), without or with anabolic implant in 2 x 2 factorial arrangement. As compared with LFC, HFO reduced dry matter intake and average daily gain, without affecting the gain:feed ratio. Feeding HFO also decreased dressing yield and backfat thickness, with no impact on the longissimus dorsi area and Warner-Bratzler shear force. Meat from steers fed HFO contained greater relative proportion of cis-9, cis-12 18:2, cis-9, trans-11 18:2, and cis-9, cis-12, cis-15 18:3 as compared with LFC. Implanted steers had greater dry matter intake, average daily gain, and gain:feed ratio. Implants improved dressing yield, tended to increase the longissimus dorsi area, decreased backfat thickness, and increased meat Warner-Bratzler shear force. Meat from implanted steers contained greater relative concentration of cis-9, cis-12 18:2 and cis-9, cis-12, cis-15 18:3, without affecting cis-9, trans-11 18:2, as compared with non-implanted animals. No interaction of diet by implant was observed for these variables.

Our objective was to study the effect of increasing postruminal supply of linseed oil (L-oil), as a source of cis-9, cis-12, cis-15 18:3, on milk fatty acid profile and to assess the resulting impact on the development of volatile degradation products during the storage of homogenized milk. Five Holstein dairy cows fitted with a rumen cannula were randomly distributed in a 5 × 5 Latin square design. Abomasal infusion of L-oil was performed at the rate of 0, 75, 150, 300, and 600 ml/d during periods of 14 d. The concentration of cis-9, cis-12, cis-15 18:3 in milk fat increased linearly with L-oil dose. Concentrations of primary (conjugated diene and triene hydroperoxides) and secondary oxidation products (1-octen-3-one, propanal, hexanal, trans-2 + cis-3-hexenals, cis-4-heptenal, trans-2, cis-6-nonadienal trans-2, trans-4-nonadienal) increased during 11 d of storage at 4°C of homogenized milk under fluorescent light. The magnitude of the increase (difference between final and initial measurements) was linearly greater for all nine lipid oxidation products evaluated in response to increasing level of infusion. Results of the current experiment have shown that milk enriched in cis-9, cis-12, cis-15 18:3 via postruminal supply of L-oil is highly prone to oxidative degradation. This low oxidative stability, exposed under controlled experimental conditions, would represent a major obstacle to those who aim to market milk enriched in polyunsaturated fatty acids.

In 2021, the National Academies of Sciences, Engineering, and Medicine (NASEM) issued an equation to predict milk fat yield using dairy cow characteristics and diet composition as input variables. This model was evaluated externally using a data set composed of 541 feed and production records obtained from 23 eastern Canadian dairy herds. The use of the developed equation requires the prediction of dry matter intake. Cow intake used in the model assessment has been obtained by NASEM equations based on (1) animal factors, or (2) a combination of feed composition and animal factors. The prediction of milk fat yield was shown to be accurate. The best prediction was obtained using intake estimated based solely on animal factors (concordance correlation coefficient = 0.68).

IntroductionThe microbiota of bulk tank raw milk is known to be closely related to that of microbial niches of the on-farm environment. Preserved forage types are partof this ecosystem and previous studies have shown variations in their microbial ecology. However, little is known of the microbiota of forage ration combinations and the transfer rates of associated species to milk.MethodsWe identified raw milk bacteria that may originate from forage rations encompassing either hay (H) or grass/legume silage uninoculated (GL) as the only forage type, or a combination of GL and corn silage uninoculated (GLC), or grass/legume and corn silage both inoculated (GLICI). Forage and milk samples collected in the fall and spring from 24 dairy farms were analyzed using 16S rRNA gene high-throughput sequencing following a treatment with propidium monoazide to account for viable cells.Results and discussionThree community types separating H, GL, and GLICI forage were identified. While the H community was co-dominated by Enterobacteriaceae, Microbacteriaceae, Beijerinckiaceae, and Sphingomonadaceae, the GL and GLICI communities showed high proportions of Leuconostocaceae and Acetobacteraceae, respectively. Most of the GLC and GLICI rations were similar, suggesting that in the mixed forage rations involving grass/legume and corn silage, the addition of inoculant in one or both types of feed does not considerably change the microbiota. Raw milk samples were not grouped in the same way, as the GLC milk was phylogenetically different from that of GLICI across sampling periods. Raw milk communities, including the GLICI group for which cows were fed inoculated forage, were differentiated by Enterobacteriaceae and other Proteobacteria, instead of by lactic acid bacteria. Of the 113 amplicon sequence variants (ASVs) shared between forage rations and corresponding raw milk, bacterial transfer rates were estimated at 18 to 31%. Silage-based forage rations, particularly those including corn, share more ASVs with raw milk produced on corresponding farms compared to that observed in the milk from cows fed hay. These results show the relevance of cow forage rations as sources of bacteria that contaminate milk and serve to advance our knowledge of on-farm raw milk contamination.

The aim of the study was to determine the effect of a Bacillus-based direct-fed microbial on performance of mid-lactating Holstein dairy cows and on their milk fatty acid composition. Six multiparous cows fitted with a rumen cannula were used in a randomized replicated crossover design. Cows received 200 g/d of either whey powder as a control or BioPlus 2B (Chr. Hansen), a commercial direct-fed microbial providing Bacillus subtilis and Bacillus licheniformis, representing a daily dose of 6.4 × 1011 cfu, and using whey powder as a carrier. The 2 experimental periods lasted 14 d and were separated by a 7-d washout interval. Samples were collected on d 0, 13, and 14 of each period. Data from d 0 were used as covariate. Significance was declared at P ≤ 0.05 and tendency at 0.05 <P ≤ 0.10. There was a 10-fold increase in the relative concentration of bacteria from the Bacillus subtilis group in the rumen when feeding direct-fed Bacillus compared with control. Treatment did not affect ruminal pH, NH3-N, or concentrations of acetate, propionate, and butyrate. However, direct-fed Bacillus increased ruminal concentrations of isovalerate and isobutyrate (tendency). Treatments did not affect lactation performance. Supplying direct-fed Bacillus enhanced milk relative concentration of anteiso 13:0 by 27.3% and of anteiso 15:0 by 6.5% and tended to increase concentrations of iso 14:0 (+41.8%) relative to control. When expressed on a yield basis, direct-fed Bacillus increased the secretion of anteiso 13:0 and decreased that of 11:0, 15:0, 17:0 (tendency), and cis-9 17:1. These variations, although limited in magnitude, indicate that milk branched-chain fatty acid composition is sensitive to ruminal microbiota modifications without changes in chemical composition of the diet.

Polyphenol oxidase in red clover (RC) silage reduces lipolysis and consequently protects its constituent fatty acids (FA) against biohydrogenation by ruminal microorganisms. Fatty acid biohydrogenation could be further inhibited by reducing the nitrogen (N) supply to ruminal bacteria. To compare the effects of RC and alfalfa (AL) silage fed in diets differing in rumen-degradable protein supply on the transfer efficiency of polyunsaturated FA from diet to milk, and on the resulting FA profile of milk fat, 8 multiparous Holstein dairy cows (72 17 days in milk) were used in a replicated 4 x 4 Latin square design (21-day periods including 14 days of adaptation). Four treatments were compared in a 2 x 2 factorial arrangement with AL or RC fed in diets formulated to provide 100% (RDP-100) or 85% (RDP-85) of calculated rumen-degradable protein requirements. Rumen-degradable protein concentrations were adjusted by varying the supplies of ground vs. steam-flaked corn grains, and untreated vs. heat-treated soybean meals. Feeding RC, as compared with AL diets, decreased ruminal ammonia-N concentration as well as urea-N in plasma and milk. Intakes of c9c12 18:2 and c9c12c15 18:3 were lower for cows fed RC, but their secretion in milk and their apparent transfer efficiency from diet were greater as compared to cows fed AL. As a result, feeding RC increased the concentrations of c9c12 18:2 and c9c12c15 18:3, but decreased the proportions of tl 1 18:1, c9t11 18:2, and t1 1c15 18:2 in milk fat. These results are consistent with the lower effective ruminal disappearance of c9c12 18:2 and c9c12c15 18:3 in RC as determined by a 96 h in sacco incubation, and the lower abundance of ruminal bacteria capable of hydrolyzing dietary lipids and hydrogenating polyunsaturated FA (Ruminococcus albus and Ruminococcus flavefaciens) in the rumen content. The apparent transfer efficiency of c9c12 18:2 from diet to milk was further increased by feeding RDP-85 as compared with RDP-100 diet. Feeding RC decreased concentrations of linear odd-chain FA (11:0, 13:0, 15:0, 17:0, and c9 17:1) and increased proportions of branched chain FA (iso13:0, iso14:0, iso15:0, iso16:0, iso17:0, anteiso15:0, and anteiso17:0) in milk fat as compared with AL. In conclusion, as compared with AL, cows fed RC produced milk with greater concentrations of major forage FA (c9c12 18:2 and c9c12c15 18:3) and lower proportions of intermediates in ruminal biohydrogenation of these FA. Variations in milk concentrations of odd-and branched-chain FA, which are synthesized in the rumen by various microbial populations, may be reflecting the effects of forage source on ruminal fermentation. (C) 2016 Published by Elsevier B.V. All rights reserved.

The objective of the current on-farm trial was to assess the impact of feeding extruded flaxseed on milk yield and composition. Thirty commercial dairy herds located in the province of Québec, Canada were recruited. The experiment began with a baseline period of 2 months during which each cow received their regular diets. Data collected during this period were used as covariate. Farms were then randomly allocated into a control group (n = 15; 767 cows) which continued to receive their regular diets, or a treatment group (n = 15; 863 cows) which received diets supplemented with extruded flaxseed (0.7 kg/d per cow) during an experimental period of 7 months. Significance was declared at P ≤ 0.05 and tendencies at 0.05 < P ≤ 0.10. Feeding extruded flaxseed did not affect feed intake but increased milk yield by 1.1 kg/d per cow, and feed efficiency by 6.5%. Dietary addition of extruded flaxseed increased milk fat (tendency) and lactose yield, whereas milk protein yield was similar between treatments. Estimated CH4 intensity were reduced by 1.3 g/L of milk (−9.2%) in herds receiving extruded flaxseed. Feeding extruded flaxseed increased milk fat concentration of cis-9, cis-12, cis-15 18:3 and total n-3 fatty acids. Results of the current on-farm trial confirm observations made under experimental conditions that feeding moderate levels of extruded flaxseed improves production performance in dairy cows.

Abstract Background Advanced maternal age and obesity are associated with impaired female fertility. Moreover, fatty acids (FA) in follicular fluid (FF) play important roles in oocyte maturation and embryo development. However, the effects of body mass index (BMI), age, and FF FA composition on embryo development between days 3 and 5 and blastocyst stage on day 5 are still unclear. Methods This study included 138 patients undergoing assisted reproductive technology (ART), which were divided into three BMI groups (18.5–24.9 kg/m2 vs. 25.0–29.9 kg/m2 vs. ≥ 30.0 kg/m2) and three age-related groups (20–30 years vs. 31–34 years vs. ≥ 35 years) which were compared for ART outcomes. Further, observations were divided into quartiles based on either of three parameters related to embryo outcome, i.e. (i) embryos developing between days 3 and 5 (ED3-5) and (ii) expanded blastocysts on day 5 (EB5), both expressed proportionally to the number of oocytes with two pronuclei (2PN), as well as (iii) the embryo utilization rate (EUR). Proportions of FF FA were then compared between Q1 and Q4, representing the quartile with the worst vs. the best embryo outcome, respectively. Finally, regression models were created to assess the relationships between BMI, age, FF total FA (TFA) concentration, relative proportions of specific FA and embryo outcome. Results Patients of Q1 had higher proportions of FF C20:5n-3, C22:6n-3 and total n-3 PUFA than Q4 patients. Furthermore, Q4 patients tended to be younger than Q1 patients. Within the whole cohort, the proportion of C20:5n-3 negatively correlated with ED3-5/2PN and EUR, while EB5/2PN tended to be negatively correlated with age. Regression models within the overweight and obese group confirmed the negative relation between C20:5n-3 and ED3-5/2PN, but also indicated additional associations: C18:1n-9 and C20:4n-6 were positively associated with ED3-5/2PN and EUR, respectively while the proportion of C18:0 was negatively associated with EUR. Conclusion The proportions of n-3 PUFA, particularly C20:5n-3 and C22:6n-3 were reduced in the patients’ quartile with the best embryo outcome. This group of patients was also younger. However, the embryo quality parameters of overweight/obese patients were not associated with age but were positively associated with FF C18:1n-9 and negatively with the proportions of C18:0 or C20:5n-3. Trial registration This study’ registration number was B670201627735.

Mammals have evolved several physiological mechanisms to cope with changes in ambient temperature. Particularly critical among them is the process of keeping the membrane of cells in a fluid phase to prevent metabolic dysfunction. In this paper, we examine variation in the fatty acid composition of bone marrow and muscle tissues in the cold-adapted caribou (Rangifer tarandus caribou) to determine whether there are systematic differences in fatty acid profiles between anatomical regions that could potentially be explained by thermal adaptation as influenced by cell function, including hematopoiesis. Our results indicate that the bone marrow and muscle tissues from the appendicular skeleton are more unsaturated than the same tissues in the axial skeleton, a finding that is consistent with physiological adaptation of the appendicular regions to thermal challenges. Because mechanisms of thermal adaptation appear to be widely shared among terrestrial mammals, we suggest that the same patterns may prevail in other species, possibly including humans.