The role of Delta(9)-desaturase in the production of cis-9, trans-11 CLA

Lithium Chloride Promotes Endogenous Synthesis of CLA in Bovine Mammary Epithelial Cells

Although conjugated linoleic acid (CLA) can promote human health, its content in milk is insufficient to have a significant impact. The majority of the CLA in milk is produced endogenously by the mammary gland. However, research on improving its content through nutrient-induced endogenous synthesis is relatively scarce. Previous research found that the key enzyme, stearoyl-CoA desaturase (SCD) for the synthesis of CLA, can be expressed more actively in bovine mammary epithelial cells (MAC-T) when lithium chloride (LiCl) is present. This study investigated whether LiCl can encourage CLA synthesis in MAC-T cells. The results showed that LiCl effectively increased SCD and proteasome α5 subunit (PSMA5) protein expression in MAC-T cells as well as the content of CLA and its endogenous synthesis index. LiCl enhanced the expression of proliferator-activated receptor-γ (PPARγ), sterol regulatory element-binding protein 1 (SREBP1), and its downstream enzymes acetyl CoA carboxylase (ACC), fatty acid synthase (FASN), lipoprotein lipase (LPL), and Perilipin 2 (PLIN2). The addition of LiCl significantly enhanced p-GSK-3β, β-catenin, p-β-catenin protein expression, hypoxia-inducible factor-1α (HIF-1α), and downregulation factor genes for mRNA expression (P < 0.05). These findings highlight that LiCl can increase the expression of SCD and PSMA5 by activating the transcription of HIF-1α, Wnt/β-catenin, and the SREBP1 signaling pathways to promote the conversion of trans-vaccenic acid (TVA) to the endogenous synthesis of CLA. This data suggests that the exogenous addition of nutrients can increase CLA content in milk through pertinent signaling pathways.

Phenotypic variation in milk fatty acid composition and its association with stearoyl-CoA desaturase 1 (SCD1) gene polymorphisms in Gir cows

Individual variation in milk fatty acid (FA) composition has been partially attributed to stearoyl-CoA desaturase 1 (SCD1) gene polymorphisms in taurine breeds, but much less is known for Zebu breeds. This study investigated the phenotypic variation in milk FA composition, and the influence of SCD1 variants on this trait and on milk fat desaturase indices (DI) in Gir cows. The functional impact of SCD1 variants was predicted using bioinformatics tools. Milk and blood samples were collected from 312 cows distributed in 10 herds from five states of Brazil. SCD1 variants were identified through target sequencing, and milk FA composition was determined by gas chromatography. Phenotypic variation in milk FA composition fell within the range reported for taurine breeds, with SCD18 index showing the lowest variation among the DI. Fourteen SCD1 variants were identified, six of which not previously described. Regarding the A293V polymorphism, all cows were homozygous for the C allele (coding for alanine), whereas all genotypes were detected for the second SNP affecting the 293 codon (G > A), with compelling evidence for functional effects. Significant associations (based on raw p-values) were found between this SNP and C12:0, cis-9, trans-11 CLA and short-chain FA, and between another SNP (rs523411937) and C15:0 and odd-chain linear FA. A new SNP on Chr26:21277069 was associated with trans-11 C18:1, cis-9, trans-11 CLA, C18:3 n-3 and n-3 FA. These findings indicate that SCD1 polymorphisms also contributes to the phenotypic variation in milk FA composition of Gir cows, with potential use in their breeding programmes.

Valorization of Olive Mill Byproducts: Recovery of Biophenol Compounds and Application in Animal Feed

This study aimed to recover the phenols from olive oil mill wastewater, a major pollutant of the oil industry, by using spray-drying technology to produce a new feed with a nutraceutical value for animal feed supplementation and to evaluate its effect on the productivity and nutritional quality of ewe milk. Forty-five Sarda ewes in late lactation (150 ± 2 d) and with homogeneous live weight (52 ± 1.5 kg) were randomly allotted into three groups and fed with three dietary treatments containing increasing levels of polyphenols: 0% (C), 0.1% (T0.1), and 0.2% (T0.2) of dry matter. No effect of the dietary treatments was found on the milk yield and composition. Interestingly, milk urea content (p < 0.0001) and somatic cell counts (p < 0.001) decreased as the level of polyphenols inclusion in the diet increased. The inclusion of phenols (0.2% of dry matter) in the diet of sheep was effective in increasing the vaccenic (C18:1 trans-11) and rumenic acid (C18: cis-9 trans-11) levels, which are beneficial for human health. Finally, the recovery of polyphenols via spray-drying technology and their incorporation into a new fortified feed can be a valid strategy for naturally improving the nutritional value of milk while valorizing an oil industry byproduct, reducing environmental impact, and promoting waste reuse that is in line with circular economy principles.

Sex effect on the fatty acid profile and chemical composition of meat from beef cattle fed a whole shelled corn diet

Abstract. This study aimed to evaluate the effect of sex on the chemical composition, fatty acid profile, and nutritional indexes of the Longissimus lumborum muscle of feedlot cattle fed a whole shelled corn diet. A total of 40 Nellore cattle were used, of which 20 animals were uncastrated bulls and 20 were heifers, with an average body weight of 411 ± 20.82 and 274 ± 17.80 kg, respectively. The diet was composed of 85 % whole shelled corn and 15 % protein–vitamin–mineral supplement. The chemical composition, fatty acid profile, and the nutritional value of the meat of the animals were evaluated. The chemical composition of the Longissimus lumborum muscle was similar among sexes (p>0.05). Differences were observed in the saturated (17 : 0, 18 : 0, and 21 : 0) and monounsaturated (16 : 1 cis-9, 17 : 1 cis-10, 18 : 1 cis-9, and 18 : 1 trans-7) fatty acid composition between sexes (p<0.05), and the polyunsaturated fatty acid (18 : 2 cis-9 and cis-12, 18:2 cis-9 and trans-11, 20 : 3 n-6, and 22 : 6 n-3) content also showed sex differences (p<0.05). The total number of saturated and polyunsaturated fatty acids was higher in bulls, and the total number of monounsaturated fatty acids was higher in heifers (p<0.05). Indicators of nutritional quality, such as the n-6 : n-3 ratio, thrombogenicity index, and Δ-9-desaturase C14, Δ-9-desaturase C16, and Δ-9-desaturase C18 indexes, were different between the sexes (p<0.05). In conclusion, sex was not found to influence chemical composition but did affect the fatty acid profile and nutritional indexes in the meat of feedlot cattle fed a whole shelled corn diet.

Producing natural functional and low-carbon milk by regulating the diet of the cattle-The fatty acid associated rumen fermentation, biohydrogenation, and microorganism response

Conjugated linoleic acid (CLA) has drawn significant attention in the last two decades for its various potent beneficial effects on human health, such as anticarcinogenic and antidiabetic properties. CLA could be generally found in ruminant products, such as milk. The amount of CLA in ruminant products mainly depends on the diet of the animals. In general, the fat content in the ruminant diet is low, and dietary fat supplementation can be provided to improve rumen activity and the fatty acid (FA) profile of meat and milk. Especially, dietary 18-carbon polyunsaturated FA (C18 PUFA), the dominant fat source for ruminants, can modify the milk FA profile and other components by regulating the ruminal microbial ecosystem. In particular, it can improve the CLA in milk, intensify the competition for metabolic hydrogen for propionate producing pathways and decrease methane formation in the rumen. Therefore, lipid supplementation appears to be a promising strategy to naturally increase the additional nutritional value of milk and contribute to lower methane emissions. Meanwhile, it is equally important to reveal the effects of dietary fat supplementation on rumen fermentation, biohydrogenation (BH) process, feed digestion, and microorganisms. Moreover, several bacterial species and strains have been considered to be affected by C18 PUFA or being involved in the process of lipolysis, BH, CLA, or methane emissions. However, no review so far has thoroughly summarized the effects of C18 PUFA supplementation on milk CLA concentration and methane emission from dairy cows and meanwhile taken into consideration the processes such as the microorganisms, digestibility, rumen fermentation, and BH of dairy cattle. Therefore, this review aims to provide an overview of existing knowledge of how dietary fat affects rumen microbiota and several metabolic processes, such as fermentation and BH, and therefore contributes to functional and low-carbon milk production.

Utilization of Waste Date Palm Leaves Biomass Ensiled with Malic or Lactic Acids in Diets of Farafra Ewes under Tropical Conditions

The aim of the current study was to evaluate the ensiling of date palm leaves (DPL) with organic acids (lactic or malic acid) for 45 day as a feed for lactating ewes under desert conditions. Two weeks before expected parturition, 50 multiparous lactating Farafra ewes (mean ± SD: 2 ± 0.3 parity, 34 ± 1.9 kg bodyweight, 25 ± 2.4 months of age, and 555 ± 13.0 g/day of previous milk production) were equally divided into five treatments in a completely randomized design for 90 day. The ewes in the control treatment were offered a diet composed of a concentrate feed mixture and DPL at 60:40 on a dry matter (DM) basis ensiled without additive. In the other treatments, DPL (ensiled without organic acids) in the control treatment was replaced with DPL ensiled with lactic or malic acid (at 5 g/kg DM) at 50 or 100% levels. Organic acids linearly and quadratically increased (p < 0.01) DPL and total intakes and digestibilities of DM, organic matter, crude protein, and nonstructural carbohydrates without affecting fiber digestibility. Malic and lactic acid treatment also increased the concentrations of ruminal total volatile fatty acids, acetate, propionate, and ammonia-N. Additionally, malic and lactic acid-treated DPL increased serum glucose concentration and total antioxidant capacity. Without affecting daily actual milk production, treatments increased (p < 0.001) the daily production of energy-corrected milk (ECM), fat-corrected milk (FCM), milk energy output, milk contents of fats, and feed efficiency. Organic acid-treated DPL increased (p < 0.05) the proportions of total polyunsaturated fatty acids and total conjugated linoleic acids and the unsaturated to saturated fatty acid ratio in milk. It is concluded that feeding DPL ensiled with malic or lactic acid at 20 or 40% of total diet DM increased daily ECM and FCM production, nutrient utilization efficiency, and milk quality. No differences were observed between lactic and malic acid treatment of DPL during ensiling; therefore, both of them are recommended to treat DPL for silage preparation.

Feeding Date-Palm Leaves Ensiled with Fibrolytic Enzymes or Multi-Species Probiotics to Farafra Ewes: Intake, Digestibility, Ruminal Fermentation, Blood Chemistry, Milk Production and Milk Fatty Acid Profile

The present experiment evaluated the feeding of date palm leaves (DPL) ensiled with fibrolytic enzymes (ENZ) or multi-species probiotics (MSP) on nutrient utilization and lactational performance of ewes. Fifty multiparous lactating Farafra ewes were used in a completely randomized design for 90 d. The treatments consisted of the control diet with a concentrate feed mixture and date palm leaves (at 60:40, DM basis) ensiled without additive (control) or DPL ensiled with ENZ or MSP replacing control DPL at 50 or 100%. Both ENZ and MSP increased (p < 0.01) DPL and total intakes, digestibility of all nutrients, concentrations of ammonia, total volatile fatty acids, acetate and propionate in the rumen. Increased milk production, concentrations of fat, lactose and energy in milk, and feed efficiency were observed with MSP and ENZ compared to the control treatment. Moreover, ENZ and MSP increased (p < 0.05) the concentrations of total n3, n6 fatty acids, polyunsaturated fatty acids and conjugated linoleic acids and decreased (p < 0.001) the atherogenicity. The differences between ENZ and MSP and between the low and high replacement levels were minor for all measured parameters. Ensiling of DPL with MSP or fibrolytic enzymes is recommended to improve feed efficiency and improve lactational performance of ewes.

Feeding hydrogenated palm fatty acids and rumen-protected protein to lactating Holstein-Friesian dairy cows modifies milk fat triacylglycerol composition and structure, and solid fat content

The aim of this study was to analyze the effect of fat and protein supplementation to dairy cattle rations on milk fat triacylglycerol (TAG) composition, fatty acid (FA) positional distribution in the TAG structure, and milk solid fat content (SFC). Fifty-six lactating Holstein-Friesian cows were blocked into 14 groups of 4 cows and randomly assigned 1 of 4 dietary treatments fed for 28 d: (1) low protein, low fat, (2) high protein, low fat, (3) low protein, high fat, and (4) high protein, high fat. The high protein and high fat diets were obtained by isoenergetically supplementing the basal ration (low protein, low fat) with rumen-protected soybean meal and rumen-protected rapeseed meal, and hydrogenated palm FA (mainly C16:0 and C18:0), respectively. Fat supplementation modified milk TAG composition more extensively compared with protein supplementation. Fat supplementation resulted in decreased concentrations of the low molecular weight TAG carbon number (CN) 26 to CN34 and medium molecular weight TAG CN40, CN44, and CN46, and increased concentrations of CN38 and the high molecular weight TAG CN50 and CN52. Increased contents of C16:0, C18:0, and C18:1cis-9 in TAG in response to fat supplementation were related to increases in the relative concentrations of C16:0 and C18:0 at the sn-2 position and C18:0 and C18:1cis-9 at the sn-1(3) positions of the TAG structure. Increased concentrations of high molecular weight TAG species CN50 and CN52 in response to fat supplementation was associated with increased milk SFC at 20, 25, and 30°C. Our study shows that important alterations in milk TAG composition and structure occur when feeding hydrogenated palm FA to lactating dairy cattle, and that these alterations result in an increased SFC of milk fat. These changes in milk SFC and TAG composition and structure may improve absorption of both fat and minerals in milk-based products for infants and may affect processing of milk fat.

Fennel and Ginger Improved Nutrient Digestibility and Milk Yield and Quality in Early Lactating Egyptian Buffaloes

The supplementation with herbal and medicinal plants to animals showed positive effects on feed digestion, performance and animal’s health. Fifteen multiparous Egyptian buffaloes (537 ± 18.1 kg body weight), 7 days after parturition, were randomly assigned to 3 treatments in a quintupled 3 × 3 Latin square design in a 63-day experiment. Each experimental period lasted 21 days (15 days of adaptation + 7 days for measurements and samples collection). Buffaloes were assigned according to their previous milk production, weight and parity to study the effect of fennel (Foeniculum vulgare) or ginger (Zingiber officinale) supplementation on feed utilization and lactational performance. Buffaloes were fed a basal diet of concentrates, berseem clover and rice straw in a ratio of 60:30:10 dry matter (DM) basis. The first group was fed the basal diet with no additive as the control treatment, while other buffaloes were fed on the basal diet supplemented with 75 g fennel or ginger/buffalo daily. Additives supplementation did not affect feed intake; however, fennel followed by ginger improved (P<0.05) dry matter, organic matter, crude protein and neutral detergent fiber digestibilities compared to the control. Without affecting blood chemistry, fennel and ginger supplementation improved (P<0.05) production of milk and energy corrected milk, fat concentration and milk energy content and output. Fennel followed by ginger decreased the somatic cell count (P=0.035) compared with the control. Fennel and ginger improved feed efficiency (P<0.05) compared with the control. Fennel increased the proportion of milk trans-10, cis-12 C18:2 (P=0.028), total conjugated linoleic acid without affecting other fatty acids. It is concluded that fennel or ginger at 75 g/buffalo/d improved nutrient digestibility and milk production of lactating buffaloes. Fennel improved milk nutritive value more than ginger.

Chlorella vulgaris Microalgae and Copper Mixture Supplementation Enhanced the Nutrient Digestibility and Milk Attributes in Lactating Boer Goats

Thirty-two lactating Boer goats (35.2 ± 1.4 kg body weight) were grouped into control and three treatment groups in completely randomised design. In treatment groups, supplementation was done as a mixture of 5 g Chlorella vulgaris + 4.5 mg of supplemental Cu/kg diet from CuSO4 (Alg5 treatment), 10 g C. vulgaris + 9 mg of supplemental Cu/kg diet (Alg10 treatment), or a mixture of 15 g C. vulgaris + 13.5 mg of supplemental Cu/kg diet (Alg15 treatment). Treatments did not affect feed intake; however, Alg10 treatment increased (P<0.001) nutrient digestibility. Treatments did not affect ruminal pH, ammonia-N, butyrate; however, the Alg10 treatment increased (P<0.01) ruminal total volatile fatty acids, propionate and acetate concentrations. Without affecting other blood measurements, the Alg10 treatment quadratically increased (P<0.001) serum glucose and Cu. The Alg10 treatments increased (P<0.001) daily milk production and the concentration of fat, and enhanced milk (feed) efficiency. The Alg10 treatment decreased (P<0.05) milk saturated fatty acids and the atherogenic index, and increased the proportions of total conjugated linoleic acids, C18:1n9t, odd fatty acids and total unsaturated fatty acids compared with the control treatment. Present study concluded that inclusion of a mixture of 10 g C. vulgaris + 9 mg Cu/kg diet in the diet of lactating Boer goats enhanced nutrient digestibility, ruminal fermentation, milk production, feed efficiency as well as milk nutritive value. Increasing the dose of the mixture to 15 g C. vulgaris + 13.5 mg Cu/kg diet is not recommended in the diet of lactating Boer goats.

A new pectinase produced from Aspergillus terreus compared with a commercial pectinase enhanced feed digestion, milk production and milk fatty acid profile of Damascus goats fed pectin-rich diet

Pectinase hydrolyses pectin and increases the utilization of agriculture byproducts as feeds for ruminants. A newly developed pectinase from Aspergillus terreus was compared with a commercially available pectinase at 600 IU/kg feed on feed utilization and lactational performance of Damascus goat fed orange pulp and sugar beet pulp based diet (i.e., pectin-rich diet) for 12 weeks. Thirty (one week postpartum) Damascus goats stratified by previous milk production, body weight and parity were divided into three experimental groups. Does were fed a basal diet containing concentrates, orange silage, sugar beet pulp and wheat straw at 50:20:20:10, respectively without a supplement (control treatment) or supplemented with a newly developed pectinase (New treatment) or commercial pectinase (Commercial treatment). With similar (P>0.05) feed intake, the new pectinase increased (P<0.01) nutrient digestibility and milk production efficiency more than the other treatments. Out of all the blood parameters, only serum glucose was affected by the treatments with highest (P=0.025) value noted for the new pectinase. Similarly, the new pectinase increased daily milk production (P<0.005) and the concentrations of milk components compared to the other two treatments. Additionally, pectinase (both the commercial and new) inclusion increased (P<0.05) the concentrations of total conjugated linoleic acid and unsaturated/saturated fatty acids ratio, and decreased atherogenic index (P=0.01) compared with control treatment. It is concluded that the supplementation of the diet of lactating goats with pectinase at 600 IU/kg feed will enhance feed digestion and milk production. The newly developed pectinase performed better than the commercial pectinase.

Fatty acid composition, shelf-life and eating quality of beef from steers fed corn or wheat dried distillers' grains with solubles in a concentrate supplement to grass silage

Thirty-six steers were randomly assigned to one of three dietary treatments fed ad libitum grass silage and concentrate supplements containing either barley/soybean meal (CON), 80% DM corn (CDGS)- or 80% DM wheat (WDGS)-dried distillers' grains with solubles for 124 days pre-slaughter. Chemical and fatty acid composition, shelf-life, and eating quality of longissimus thoracis muscle were determined. Dietary CDGS and WDGS increased the proportion of conjugated linoleic acids (P < 0.05) and tended to increase C18:3n-3 (P = 0.075) and total polyunsaturated fatty acids (P = 0.060) relative to the CON. Feeding diets containing distillers' grains reduced the lipid and colour stability of fresh beef patties stored in modified atmosphere packs (MAP), with CDGS exhibiting an intermediate effect between CON and WDGS. Diet did not negatively influence the texture profile parameters and eating quality attributes of beef stored in MAP. The inclusion of CDGS or WDGS in supplementary concentrates may improve the fatty acid profile but decreased the shelf-life of beef.

Partially replacing sorghum silage with cactus (Opuntia stricta) cladodes in a soybean oil-supplemented diet markedly increases trans-11 18:1, cis-9, trans-11 CLA and 18:2 n-6 contents in cow milk

Based on low 18:0 contents observed in milk fat of cows fed cactus cladodes (CC), we hypothesized that including Opuntia stricta cladodes in a soybean oil (SO)-supplemented diet would promote incomplete rumen biohydrogenation of supplemental PUFA, leading to increased trans-11 18:1 and cis-9, trans-11 CLA contents in milk. Twelve Holstein cows were used in a two-period study: (a) Baseline: all cows received a total mixed ration (TMR) composed of sorghum silage (SS) and a concentrate containing no SO for 14 days; (b) Treatment: cows received one of the following SO-supplemented diets for 21 days: (1) SS-TMR: a TMR composed of SS and a SO-enriched concentrate, (2) CC-TMR: a TMR containing CC as a partial substitute for SS plus the SO-enriched concentrate, and (3) CC-PMR: same diet as in treatment 2, but CC were mixed with the SO-enriched concentrate and fed as a partial mixed ration (PMR). Both CC diets increased relative abundances of trans-11 18:1, cis-9, trans-11 CLA, and 18:2 n-6 in milk fat, whereas opposite effects were observed on 18:0 and cis-9 18:1. Proportion of 18:2 n-6 increased, and cis-9, trans-11 CLA tended to increase with CC-PMR as compared to CC-TMR, whereas 18:3 n-3 was higher with CC-PMR than with SS-TMR. Proportions of several odd- and branched-chain fatty acids, certain 18:1 isomers, and trans-9, cis-11 CLA changed with CC diets, notably with CC-PMR. Milk yield and intake of most nutrients (except fibre) increased or tended to increase with the CC diets, whereas gross milk composition was unaltered. Stearoyl-CoA desaturase-1 index for C18 (SCD₁₈ ) was higher with CC-PMR than with SS-TMR, and milk n-6:n-3 FA ratio and apparent transfer of 18:2 n-6 to milk increased with CC diets. These results indicate that Opuntia stricta cladodes can be a valuable feed ingredient for improving the nutraceutical value of milk fat.

The Effect of CLA-Rich Isomerized Poppy Seed Oil on the Fat Level and Fatty Acid Profile of Cow and Sheep Milk

The aim of the study was to examine the effect of dietary supplementation of isomerized poppy seed oil (IPO) enriched with conjugated dienes of linoleic acid (CLA) on cow and sheep milk parameters (fat content, fatty acid profile, Δ9-desaturase index, and atherogenic index). The process of poppy seed oil alkaline isomerization caused the formation of CLA isomers with cis-9,trans-11, trans-10,cis-12, and cis-11,trans-13 configurations in the amounts of 31.2%, 27.6%, and 4.1% of total fatty acids (FAs), respectively. Animal experiments were conducted on 16 Polish Holstein Friesian cows (control (CTRL) and experimental (EXP), n = 8/group) and 20 East Friesian Sheep (CTRL and EXP, n = 10/group). For four weeks, animals from EXP groups received the addition of IPO in the amount of 1% of dry matter. Milk was collected three times: on days 7, 14, and 30. Diet supplementation with IPO decrease milk fat content (p < 0.01). Milk fat from EXP groups had higher levels of polyunsaturated fatty acids, including FAs with beneficial biological properties, that is, CLA and TVA (p < 0.01), and lower levels of saturated fatty acids, particularly short- (p < 0.01) and medium-chain FAs (p < 0.05). The addition of IPO led to a decrease in the atherogenic index.

Volatile Profile in Yogurt Obtained from Saanen Goats Fed with Olive Leaves

The aim of this study was to evaluate the development of volatile compounds in yogurt samples obtained from goats fed a dietary supplementation with olive leaves (OL). For this purpose, thirty Saanen goats were divided into two homogeneous groups of 15 goats each: a control group that received a standard diet (CG) and an experimental group whose diet was supplemented with olive leaves (OLG). The trial lasted 28 days, at the end of which the milk of each group was collected and used for yogurt production. Immediately after production, and after 7 days of storage at 4 °C in the absence of light, the yogurt samples were characterized in terms of fatty acid profile, oxidative stability and volatile compounds by the solid-phase microextraction (SPME)-GC/MS technique. Dietary OL supplementation positively affected the fatty acid composition, inducing a significant increase in the relative proportion of unsaturated fatty acids, mainly oleic acid (C18:1 cis9) and linolenic acid (C18:3). With regard to the volatile profile, both in fresh and yogurt samples stored for 7 days, the OL supplementation induced an increase in free fatty acids, probably due to an increase in lipolysis carried out by microbial and endogenous milk enzymes. Specifically, the largest variations were found for C6, C7, C8 and C10 free fatty acids. In the same samples, a significant decrease in aldehydes, mainly heptanal and nonanal, was also detected, supporting-at least in part-an improvement in the oxidative stability. Moreover, alcohols, esters and ketones appeared lower in OLG samples, while no significant variations were observed for lactones. These findings suggest the positive role of dietary OL supplementation in the production of goats' milk yogurt, with characteristics potentially indicative of an improvement in nutritional properties and flavor.

Effect of Soy Lecithin Supplementation in Beef Cows before Calving on Colostrum Composition and Serum Total Protein and Immunoglobulin G Concentrations in Calves

Simple Summary

Until recently, fat supplements were considered merely as a source of energy for cows during transition. However, individual fatty acids included in fat supplements may clearly induce different production and metabolic responses, which in consequence change the nutritional value of bovine colostrum. Therefore, it is necessary to consider the type of fat additive to use in feed ration. This study aimed to determine an effect of soy lecithin supplementation on beef cow’s colostrum composition and selected blood parameters in their calves. Obtained results suggest that soy lecithin addition in cows before calving has a beneficial impact on colostrum composition. This concerns mainly an increase of linoleic acid in colostrum, which may influence IgG activity in calf serum. In turn, higher content of these components in colostrum may contribute to improve calves’ survival rate during the first weeks of their life.

Abstract

The aim of this study was to investigate the impact of soy lecithin supplementation in beef cow’s nutrition on colostrum composition and serum concentrations of immunoglobulin G (IgG) and serum total protein (STP) in calves. Twenty pregnant Charolaise cows were assigned to two groups. In the supplementation group (n = 10) during the last four weeks of pregnancy, soy lecithin was administrated in an amount of 20 g/cow/day. In both groups, basic composition (protein, fat, lactose, dry matter), somatic cell count (SCC), total bacteria count (TBC), IgG concentration, and fatty acids profile were determined in colostrum samples. Moreover, STP and IgG concentration were measured in calves’ blood samples on the 3rd, 7th, 14th, and 21st days of life, mothered by supplementation and control cows. Animals fed with soy lecithin before calving produced colostrum with a higher (p = 0.049) level of linoleic acid (C18:2 n-6). In addition, these results showed that soy lecithin supplementation has contributed to an increase (p = 0.029) of serum IgG in calves on the 14th day of life. The impact of such change in colostrum on IgG levels on calves serum and their half-life need further analysis.

The links between supplementary tannin levels and conjugated linoleic acid (CLA) formation in ruminants: A systematic review and meta-analysis

A systematic review and meta-analysis were conducted to predict and identify ways to increase conjugated linoleic acid (CLA) formation in ruminant-derived products to treat human health issues with dietary tannins. The objective was to compare and confirm the effects of dietary tannins on CLA formation by analyzing in vitro and/or in vivo studies. We reported the results of the meta-analysis based on numerical data from 38 selected publications consisting of 3712 treatments. Generally, via multiple pathways, the CLA formation increased when dietary tannins increased. Concurrently, dietary tannins increased Δ⁹ desaturation and the CLA indices in milk and meat (P < 0.05 and P < 0.001, with average R² values of 0.23 and 0.44, respectively), but they did not change the rumen fermentation characteristics, including total volatile fatty acids (mmol/L) and their acid components. In vitro observations may accurately predict in vivo results. Unfortunately, there was no relationship between in vitro observations and in vivo results (R² < 0.10), indicating that it is difficult to predict CLA formation in vivo considering in vitro observations. According to the statistical meta-analysis results regarding animal aspects, the ranges of tannin levels required for CLA formation in vitro and in vivo were approximately 0.1–20 g/kg dry matter (DM) (P < 0.001) and 2.1–80 g/kg DM (P < 0.001), respectively. In conclusion, the in vivo method was more suitable for the direct observation of fatty acid transformation than the in vitro method.

Fatty acids as biomarkers of total dairy and dairy fat intakes: a systematic review and meta-analysis

Context

Dairy intake in humans is commonly assessed using questionnaires, but the data collected are often biased. As a result, there is increasing interest in biomarkers of dairy fat. To date, there has been no overview of the fatty acids suitable for use as biomarkers of dairy fat intake.

Objective

This systematic review and meta-analysis of observational studies was performed to identify circulating fatty acids as biomarkers of total dairy and dairy fat intakes in the general population.

Data Sources

MEDLINE, Embase, and Web of Knowledge databases were searched for eligible studies published until June 2017.

Study Selection

Articles were included when a correlation between circulating dairy fatty acids and intakes of total dairy and dairy fat was found, as measured by dietary assessment tools.

Data Extraction

Two authors extracted data independently and assessed the risk of bias. An adapted form of the Newcastle-Ottawa Scale was used for quality assessment.

Results

Data were pooled using the random-effects model. Meta-analysis revealed that the fatty acids in plasma/serum were significantly correlated with intakes of total dairy (C14:0 [r = 0.15; 95%CI, 0.11 - 0.18], C15:0 [r = 0.20; 95%CI, 0.13 - 0.27], and C17:0 [r = 0.10; 95%CI, 0.03 - 0.16] and dairy fat (C14:0 [r = 0.16; 95%CI, 0.10 - 0.22], C15:0 [r = 0.33; 95%CI, 0.27 - 0.39], C17:0 [r = 0.19; 95%CI, 0.14 - 0.25], and trans-C16:1n-7 [r = 0.21; 95%CI, 0.14 - 0.29).

Conclusions

C14:0, C15:0, C17:0, and trans-C16:1n-7 were identified as biomarkers of total dairy and dairy fat intakes in the general population. In light of the suboptimal measurement techniques used in some studies, correlations with trans-C18:1n-7 and conjugated linoleic acid require further investigation.

Fatty acid biosynthesis and transcriptional regulation of Stearoyl-CoA Desaturase 1 (SCD1) in buffalo milk

Background

Buffalo milk is considered as a highly nutritious food owing to its higher contents of fatty acids (FA) and rich nutrient profile. Higher fat contents of buffalo milk make it suitable for processing to develop various healthy and nutritious products. Moreover, buffalo milk contains more unsaturated FAs (UFA) such as oleic and linolenic acid, which are important from the human health point of view owing to their desirable physiological effects. However, inadequate information is available about the chemical composition and mechanism of FA synthesis in buffalo milk. In this study, we hypothesized that expression of SCD1 gene could alter the biosynthesis of FA in epithelial cells of mammary gland and subsequently affect the FA contents in buffalo milk. We investigated the transcriptional and biological role of Stearoyl-CoA Desaturase 1 (SCD1) in the buffalo mammary epithelial cells (BMECs) during FA and triacylglycerol (TAG) synthesis.

Results

Results revealed that unsaturated fatty acid contents were much higher in concentration in buffalo milk as compared to Holstein cow. Significant increase in the expression level of FAS, ACACA, SREBP1, PPARG, GPAT, and AGPAT genes was observed in response to altered expression of SCD1 in buffalo milk. Moreover, change in SCD1 gene in BMECs also mediated the expression of genes related to FA biosynthesis subsequently leading to alter the FA composition. Overexpression of SCD1 significantly increased the expression of genes associated with FA and TAG synthesis leading to enhance FA and unsaturated FA contents in BMECs. However, down-regulation of SCD1 exhibited opposite consequences.

Conclusion

Our study provides mechanistic insights on transcriptional regulation of SCD1 to alter FA and TAG synthesis through directly or indirectly mediating biosynthesis and metabolic pathways in BMECs. We provide preliminary findings regarding engineering of FA contents in buffalo milk through SCD1 signaling.

Sterculic Acid: The Mechanisms of Action beyond Stearoyl-CoA Desaturase Inhibition and Therapeutic Opportunities in Human Diseases

In many tissues, stearoyl-CoA desaturase 1 (SCD1) catalyzes the biosynthesis of monounsaturated fatty acids (MUFAS), (i.e., palmitoleate and oleate) from their saturated fatty acid (SFA) precursors (i.e., palmitate and stearate), influencing cellular membrane physiology and signaling, leading to broad effects on human physiology. In addition to its predominant role in lipid metabolism and body weight control, SCD1 has emerged recently as a potential new target for the treatment for various diseases, such as nonalcoholic steatohepatitis, Alzheimer’s disease, cancer, and skin disorders. Sterculic acid (SA) is a cyclopropene fatty acid originally found in the seeds of the plant Sterculia foetida with numerous biological activities. On the one hand, its ability to inhibit stearoyl-CoA desaturase (SCD) allows its use as a coadjuvant of several pathologies where this enzyme has been associated. On the other hand, additional effects independently of its SCD inhibitory properties, involve anti-inflammatory and protective roles in retinal diseases such as age-related macular degeneration (AMD). This review aims to summarize the mechanisms by which SA exerts its actions and to highlight the emerging areas where this natural compound may be of help for the development of new therapies for human diseases.

Conjugated linoleic acid as a potential bioactive molecule to modulates gamete and embryo cryotolerance

Abstract Conjugated linoleic acid (CLA) is a mixture of positional isomers of linoleic acid found in meat and dairy products from ruminants. It is a trans fat widely used by athletes as a food supplement, due to a supposed effect of maximizing the use of body fat reserves. The interest in diet and culture media supplementation with CLA is an emerging area, demanding studies in order to elucidate its benefits in the reproductive parameters, as well as in cryopreservation. Therefore, the aim of this review was to discuss the effects of CLA on the oocytes, sperm and embryos cryotolerance. Some studies have already demonstrated its use in cryopreservation of germline. Among those, it was observed that CLA supplementation during oocyte in vitro maturation can increase their viability post-freezing and developmental capacity. Regarding the use of CLA on sperm, there are few studies and their results are still inconclusive. Finally, studies about CLA supplementation on embryo culture media have shown promising results, indicating that this bioactive molecule is able to modulate lipid uptake on blastomeres. Altogether, these findings demonstrate the potential use of CLA as a bioactive molecule to improve germline and embryo cryotolerance and open new perspectives on human and animal reproduction field.

Grazing on Upland Pastures Part-Time Instead of Full-Time Affects the Feeding Behavior of Dairy Cows and Has Consequences on Milk Fatty Acid Profiles

Simple Summary

Transhumance of dairy cows to upland pastures during summer is a tradition in mountain farming systems. Different management systems are practiced in the upland depending on topography and available infrastructures. This study aimed to assess the effects of two traditionally practiced upland pasture management systems (full-time grazing and part-time grazing) on feeding behavior and milk yield and quality. Cows with access to pasture for only 6 h per day had different feeding behaviors than cows on pasture 24 h per day; their milk yields, however, were similar. Although protein and casein contents were higher in the milk of cows with full-time access to pasture, milk coagulation properties did not differ between the two systems. The differences found in milk fatty acid profiles suggest that cows with part-time access to pasture mobilized more body fat reserves to counterbalance the energy expenditures required during fasting periods and for walking back and forth between the barn and the pastures.

Abstract

Different grazing management systems are practiced on upland dairy farms during summer, depending on topography, local traditions, and infrastructure. The present experiment compared two distinct management systems with respect to feeding behavior and milk-related properties. Two similar groups of eight Valdostana Red Pied cows originating from two farms were followed during three grazing events in summer on three upland grazing sites. Cows in the full-time grazing group were kept exclusively on pasture and milked twice daily in a mobile milking parlor. Cows in the part-time grazing group had access to pasture for 4 h and 2 h after their morning and evening milkings, respectively. The part-time grazing cows differed markedly in their feeding behavior; they exhibited shorter daily ingestion times and longer durations of ingestion and idling bouts than full-time grazing cows. Part-time grazing cows had lower milk protein and casein contents, but milk yield and milk coagulation properties did not differ from the full-time grazing cows. As a result of the fasting periods in the barn, part-time grazing cows synthesized less fatty acids de novo and mobilized body fat reserves, as evidenced by the higher proportion of oleic acid in their milk fat.

Genetic Variability in the Loci of FABP4, PPARγ and SCD Genes of Sheep Breeds Raised for Different Purposes

The present study was undertaken to analyse the genetic variation in coding sequences, splicing sites and regulatory sequences of FABP4, PPARγ and SCD genes in five breeds of sheep raised in Poland with different purposes: meat (Suffolk, Ile de France), dairy/prolific (Olkuska sheep, Kołuda) and primitive breeds (Polish Mountain Sheep). To identify genetic variability HRM-PCR, sequencing and PCR-RFLP method were used. Determining the genetic structure of the mentioned genes revealed six SNPs: FABP4 – c.73 + 13A>T and c.348 + 85G>A, PPARγ – c.391 – 66C>T (c.481 – 66C>T) and c.529 + 27G>C (c.619 + 27G>C), SCD – c.*945G>A and c.*1116A>G. For the c.*1116A>G SNP, a potential association with specific sheep body type and breeding purpose was found. In turn, the substitution c.*945G>A located in the regulatory region of the 3'-UTR of the Ovis aries SCD gene was identified for the first time. Based on the relationship demonstrated between sheep body constitution and productive type (dairy, meat) and the polymorphism of the SCD gene, further research is needed. The correlation between c.*1116A>G polymorphism and growth rate, slaughter and carcass value as well as meat quality of lambs needs to be studied in more detail. Such studies may lead to more effective selection processes in sheep breeding in the future.

Conjugated linoleic acid producing potential of lactobacilli isolated from goat (AXB) rumen fluid samples

OBJECTIVE

The present investigation was aimed to explore the potential of lactobacilli for conjugated linoleic acid (CLA) production, isolated from rumen fluid samples of lactating goats.

METHODS

A total of 64 isolates of lactobacilli were obtained using deMan-Rogosa-Sharpe (MRS) agar from rumen fluid of goats and further subjected to morphological and biochemical characterizations. Isolates found as gram-positive, catalase negative rods were presumptively identified as Lactobacillus species and further confirmed by genus specific polymerase chain reaction (PCR). The phylogenetic tree was constructed from the nucleotide sequences using MEGA6.

RESULTS

Out of the 64 isolates, 23 isolates were observed positive for CLA production by linoleate isomerase gene-based amplification and quantitatively by UV-spectrophotometric assay for the conversion of linoleic acid to CLA as well as gas chromatography-based assay. In all Lactobacillus species cis9, trans11 isomer was observed as the most predominant CLA isomer. These positive isolates were identified by 16S rRNA gene-based PCR sequencing and identified to be different species of L. ingluviei (2), L.salivarius (2), L. curvatus (15), and L. sakei (4).

CONCLUSION

The findings of the present study concluded that lactic acid bacteria isolated from ruminal fluid samples of goat have the potential to produce bioactive CLA and may be applied as a direct fed microbial to enhance the nutraceutical value of animal food products.

Vegetable Oils Rich in Polyunsaturated Fatty Acids Supplementation of Dairy Cows' Diets: Effects on Productive and Reproductive Performance

Simple Summary

Ruminants milk contains some bioactive lipids that have a beneficial effect on human health. The present study aimed to evaluate the benefit of incorporating polyunsaturated fatty acids rich vegetable oils on productive and reproductive performance of dairy cows. The results show that including polyunsaturated fatty acids and rich vegetable oils in rations of dairy cows improve the nutritional profile of milk and some reproductive parameters. Ruminant milk often has a negative image for health because of its fat content and its composition. A way to improve the nutritional profile of the milk is to supplement dairy cows’ diets with polyunsaturated vegetable oils, which makes it healthier for the consumer and improves the commercial value of the milk in view of the continued decline in fertility among dairy cows. The possibility of supplementing the diet with vegetable oils rich in polyunsaturated fatty acids as a means of improving reproductive performance has considerable interest for dairy producers.

Abstract

The aim of this study was to determine how polyunsaturated fatty acids (PUFA) supplementation can affect the productive and reproductive performance in dairy cows subjected to a fixed-time artificial insemination (TAI) protocol under farm conditions. One hundred and ninety-eight Holstein non-pregnant cows were used. Treatments consisted of a control diet (CON), without added oil, and two diets supplemented with either 2.3% soybean oil (SOY) or 2.3% linseed oil (LIN) as dry matter. The diets were formulated to be isoenergetic and isoproteic. Dry matter intake and milk yield were similar among treatments (p > 0.05). Both the percentage of fat (p = 0.011) and protein (p = 0.022) were higher in milk from animals not fed with oil (CON). The greatest saturated fatty acid (SFA) concentration (p < 0.0001) was observed in milk from cows fed the control diet, without added oil. The monounsaturated fatty acids (MUFA), PUFA, and the n-3 PUFA content was higher (p < 0.0001) in the milk from animals fed with oil with respect to the control treatment. The C18:2 cis-9, trans-11 in the milk of animals fed with oil supplements was significantly higher (p < 0.0001) than in that of the control group. Animals supplemented with linseed oil tended to show higher plasma progesterone level (p = 0.09) and a higher number of pregnant cows on the first artificial insemination (p = 0.07). These animals tended to reduce the number of TAI (p = 0.08). In brief, results showed that vegetable oils rich in PUFA supplementation considerably improve the nutritional profile of milk. PUFA n-3 supplementation slightly improves some reproductive parameters in dairy cows subjected to the fixed-time artificial insemination (TAI) protocol.

Influence of dietary cardoon meal on growth performance and selected meat quality parameters of lambs, and the antioxidant potential of cardoon extract in ovine muscle homogenates

Fatty acids and oxidative stability were determined in meat from lambs fed a diet containing 15% dehydrated alfalfa (CON, n = 8) or cardoon meal (CMD, n = 7). Furthermore, the antioxidant activity of a phenolic-rich cardoon meal extract (1.32 GAE mg/ml) was examined in muscle homogenates (0, 0.5, 1, 5% v/w) subjected to iron/ascorbate-induced oxidation. Feeding CMD did not affect lamb performances and carcass traits but reduced (P < 0.05) the vaccenic and rumenic acids and increased stearic acid in muscle. Lipid oxidation was higher in raw meat from the CMD-fed lambs after 7 days of storage (P < 0.05). Feeding CMD did not affect the colour stability of raw meat and the oxidative stability of cooked meat and of muscle homogenates incubated with pro-oxidant catalysts. Adding 5% cardoon extract in muscle homogenates increased (+114.3%; P = 0.03) the total phenolic content and reduced (-77.6%; P < 0.01) lipid oxidation, demonstrating the antioxidant potential of compounds present in cardoon meal.

Genetic and genomic analyses of latent variables related to the milk fatty acid profile, milk composition, and udder health in dairy cattle

The aim of this study was to perform genetic, genome-wide association (GWAS), and gene-set enrichment analyses with latent variables related to milk fatty acid profile (i.e., fatty acids factor scores; FAF), milk composition, and udder health in a cohort of 1,158 Italian Brown Swiss cows. The phenotypes under study were 12 FAF previously identified through factor analysis and classified as follows: de novo FA (F1), branched-chain FA-milk yield (F2), biohydrogenation (F3), long-chain fatty acids (F4), desaturation (F5), short-chain fatty acids (F6), milk protein and fat contents (F7), odd fatty acids (F8), conjugated linoleic acids (F9), linoleic acid (F10), udder health (F11) and vaccelenic acid (F12). (Co)variance components were estimated for factor scores using a Bayesian linear animal model via Gibbs sampling. The animals were genotyped with the Illumina BovineSNP50 BeadChip v.2 (Illumina Inc., San Diego, CA). A single marker regression model was fitted for GWAS analysis. The gene-set enrichment analysis was run on the GWAS results using the Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway databases to identify the ontologies and pathways associated with the FAF. Marginal posterior means of the heritabilities of the aforementioned FAF ranged from 0.048 for F12 to 0.310 for F5. Factors F1 and F6 had the highest number of relevant genetic correlations with the other traits. The genomic analysis detected a total of 39 significant SNP located on 17 Bos taurus autosomes. All latent variables produced signals except for F2 and F10. The traits with the highest number of significant associations were F11 (17) and F12 (7). Gene-set enrichment analyses identified significant pathways (false discovery rate 5%) for F3 and F7. In particular, systemic lupus erythematosus was enriched for F3, whereas the MAPK (mitogen-activated protein kinase) signaling pathway was overrepresented for F7. The results support the existence of important and exploitable genetic and genomic variation in these latent explanatory phenotypes. Information acquired might be exploited in selection programs and when designing further studies on the role of the putative candidate genes identified in the regulation of milk composition and udder health.

The fatty acid composition of ewe milk or suckling lamb meat can be used to discriminate between ewes fed different diets

Thirty-nine ewe-lamb pairs were used to evaluate the effects of the diet of lactating ewes, the type of forage (pasture vs hay) and the inclusion of 10% quebracho in the concentrate on the fatty acid (FA) profile of their milk and the meat of their suckling lambs. The estimated forage–concentrate ratio was 80:20. Milk from pasture ewes had a higher percentage of saturated FAs (SFAs; 62.3 vs 56.5), lower percentages of monounsaturated FAs (MUFAs; 30.4 vs 36.6) and n-6 polyunsaturated FAs, and a lower n-6:n-3 ratio (1.9 vs 2.3) than did that of hay ewes (P &lt; 0.001). Meat of pasture lambs had higher percentages of total polyunsaturated FAs (PUFAs; 23.0 vs 20.4; P &lt; 0.05) and n-3 (7.0 vs 5.0; P &lt; 0.001) and lower percentages of MUFAs (37.9 vs 41.8; P &lt; 0.001) and n-6:n-3 (2.0 vs 2.8; P &lt; 0.001) than did that of hay lambs. The inclusion of quebracho increased MUFAs in milk (P &lt; 0.05) and decreased SFAs in meat (P &lt; 0.05). Ewes were correctly classified to the different treatments by using the FA profile of milk (100% score outcome), and to a lesser extend by using the FA profile of lamb (82–100% score outcome); de novo synthesis of FAs in lamb muscle might have reduced the classification accuracy. In conclusion, forage type had a greater effect on the FA profiles of ewe milk and the meat of suckling lambs than did the inclusion of quebracho in the concentrate. To improve the classification of meat of suckling lamb, other biomarkers should be examined. These results are relevant for ewes farmed for the production of milk as well as lambs.

Fatty Acid Desaturase 3 (FADS3) Is a Specific ∆13-Desaturase of Ruminant trans-Vaccenic Acid

In mammalian species, the Fatty Acid Desaturase (FADS) gene cluster includes FADS1 (∆5-desaturase), FADS2 (∆6-desaturase), and a third gene member, named FADS3. According to its high degree of nucleotide sequence homology with both FADS1and FADS2, FADS3 was promptly suspected by researchers in the field to code for a new mammalian membrane-bound fatty acid desaturase. However, no catalytic activity was attributed to the FADS3 protein for a decade, until the rat FADS3 protein was shown in vitro to be able to catalyze the unexpected ∆13-desaturation of trans-vaccenic acid, producing the trans11,cis13-conjugated linoleic acid isomer. This review summarizes the recent investigations establishing the FADS3 enzyme as a reliable mammalian trans-vaccenate ∆13-desaturase in vivo and tries to identify further unresolved issues that need to be addressed.

Growth performance, carcass and meat quality of lambs supplemented different vegetable oils

Objective

The purpose of this study was to evaluate the effect of rapeseed and linseed oil supplementations on performance and meat quality of lambs.

Methods

The experiment was conducted on 18 growing (100-day-old) lambs of 19.7±1.9 kg live weight, assigned to 3 groups of 6 animals each. Control lambs were fed meadow hay and concentrate alone. Experimental animals additionally received rapeseed or linseed oils at a dose of 50 g/d. The lambs were slaughtered at an average body weight of 35.7±0.5 kg.

Results

The dressing percentage was higher in lambs fed rapeseed oil. Total saturated fatty acids (SFA) and C15:0, C16:0, C17:0, C21:0, C24:0 were lower in longissimus dorsi muscle (MLD) in lambs fed linseed oil. Supplementation of diet with linseed oil decreased concentrations of total monounsaturated fatty acids and C16:1, C17:1, C18:1 cis-9 in MLD. The concentrations of n-3 polyunsaturated fatty acids (PUFA) and C18:3 n-3, C20:5 n-3 in MLD were higher in lambs fed linseed oil than in other groups. Oils supplementation to diets resulted in increased concentration of C22:6 n-3 in MLD. The inclusion of linseed oil into the diet increased the contents of total PUFA, n-3 PUFA and C18:3 n-3, C20:5 n-3, C22:6 n-3 in semitendinosus muscle in comparison to control. A tendency towards a lower n:6/n:3 ratio in MLD was observed when lambs were supplemented linseed oil.

Conclusion

The supplementation of linseed oil to diets seems to reduce the concentration of SFA and increase the concentration of n-3 PUFA. The n-6/n-3 ratio is an important nutritional factor, and its value has been favorably decreased below 2, thereby achieving an important target related to human health. Due to these changes carcass fatty acid profile was improved, and so enhanced lamb meat healthy properties.

Conversion of dietary trans-vaccenic acid to trans11,cis13-conjugated linoleic acid in the rat lactating mammary gland by Fatty Acid Desaturase 3-catalyzed methyl-end Δ13-desaturation

In vitro, the rat Fatty Acid Desaturase 3 (FADS3) gene was shown to code for an enzyme able to catalyze the unexpected Δ13-desaturation of trans-vaccenic acid, producing the trans11,cis13-conjugated linoleic acid (CLA) isomer. FADS3 may therefore be the first methyl-end trans-vaccenate Δ13-desaturase functionally characterized in mammals, but the proof of this concept is so far lacking in vivo. The present study therefore aimed at investigating further the putative in vivo synthesis of trans11,cis13-CLA from dietary trans-vaccenic acid in rodents. During one week of pregnancy and two weeks post-partum, Sprague-Dawley female rats were fed two diets either high (10.0% of fatty acids and 3.8% of energy intake) or low (0.4% of fatty acids and 0.2% of energy intake) in trans-vaccenic acid. The trans11,cis13-CLA was specifically detected, formally identified and reproducibly quantified (0.06% of total fatty acids) in the mammary gland phospholipids of lactating female rats fed the high trans-vaccenic acid-enriched diet. This result was consistent with FADS3 mRNA expression being significantly higher in the lactating mammary gland than in the liver. Although the apparent metabolic conversion is low, this physiological evidence demonstrates the existence of this new pathway described in the lactating mammary gland and establishes the FADS3 enzyme as a reliable mammalian trans-vaccenate Δ13-desaturase in vivo.

Protein engineering: Regulatory perspectives of stearoyl CoA desaturase

Stearoyl Co A desaturase (SCD) is a rate-limiting lipogenic enzyme that plays an integral role in catalyzing the synthesis of monounsaturated fatty acids, chiefly oleate and palmitoleate. Both contribute a major part of the biological membrane. Numerous SCD isoforms exist in mouse and humans, i.e., SCD-1 to SCD-4 and SCD-1 and SCD-5, respectively. From the biological viewpoint, hyperexpression of SCD1 cause many metabolic disorders including obesity, insulin resistance, hypertension, and hypertriglyceridemia, etc. Herein, an effort has been made to highlight the value of protein engineering in controlling the SCD-1 expression with the involvement of different inhibitors as therapeutic agents. The first part of the review describes Stearoyl CoA desaturase index and different SCD isoforms. Various regulatory aspects of SCD are reviewed in four subsections, i.e., (1) hormonal regulation, (2) regulation by dietary carbohydrates, (3) regulation by green tea, and (4) regulation via polyunsaturated fatty acids (PUFAs). Moreover, the regulation of Stearoyl CoA desaturase expression in the metabolism of fats and carbohydrates is discussed. The third part mainly focuses on natural and synthetic inhibitors. Towards the end, information is also given on potential future considerations of SCD-1 inhibitors as metabolic syndrome therapeutics, yet additional work is required.

Nitro-fatty acid formation and metabolism

Nitro-fatty acids (NO₂-FA) are pleiotropic modulators of redox signaling pathways. Their effects on inflammatory signaling have been studied in great detail in cell, animal and clinical models primarily using exogenously administered nitro-oleic acid. While we know a considerable amount regarding NO₂-FA signaling, endogenous formation and metabolism is relatively unexplored. This review will cover what is currently known regarding the proposed mechanisms of NO₂-FA formation, dietary modulation of endogenous NO₂-FA levels, pathways of NO₂-FA metabolism and the detection of NO₂-FA and corresponding metabolites.

Effect of replacing calcium salts of palm oil with camelina seed at 2 dietary ether extract levels on digestion, ruminal fermentation, and nutrient flow in a dual-flow continuous culture system

Camelina is a drought- and salt-tolerant oil seed, which in total ether extract (EE) contains up to 74% polyunsaturated fatty acids. The objective of this study was to assess the effects of replacing calcium salts of palm oil (Megalac, Church & Dwight Co. Inc., Princeton, NJ) with camelina seed (CS) on ruminal fermentation, digestion, and flows of fatty acids (FA) and AA in a dual-flow continuous culture system when supplemented at 5 or 8% dietary EE. Diets were randomly assigned to 8 fermentors in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square design, with four 10-d experimental periods consisting of 7 d for diet adaptation and 3 d for sample collection. Treatments were (1) calcium salts of palm oil supplementation at 5% EE (MEG5); (2) calcium salts of palm oil supplementation at 8% EE (MEG8); (3) 7.7% CS supplementation at 5% EE (CS5); and (4) 17.7% CS supplementation at 8% EE (CS8). Diets contained 55% orchardgrass hay, and fermentors were fed 72 g of dry matter/d. On d 8, 9, and 10 of each period, digesta effluent samples were taken for ruminal NH₃, volatile fatty acids, nitrogen metabolism analysis, and long-chain FA and AA flows. Statistical analysis was performed using the MIXED procedure (SAS Institute Inc., Cary, NC). We detected an interaction between FA source and dietary EE level for acetate, where MEG8 had the greatest molar proportion of acetate. Molar proportions of propionate were greater and total volatile fatty acids were lower on CS diets. Supplementation of CS decreased overall ruminal nutrient true digestibility, but dietary EE level did not affect it. Diets containing CS had greater biohydrogenation of 18:2 and 18:3; however, biohydrogenation of 18:1 was greater in MEG diets. Additionally, CS diets had greater ruminal concentrations of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid. Dietary EE level at 8% negatively affected flows of NH₃-N (g/d), nonammonia N, and bacterial N as well as the overall AA outflow. However, treatments had minor effects on individual ruminal AA digestibility. The shift from acetate to propionate observed on diets containing CS may be advantageous from an energetic standpoint. Moreover, CS diets had greater ruminal outflow of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid than MEG diets, suggesting a better FA profile available for postruminal absorption. However, dietary EE at 8% was deleterious to overall N metabolism and AA outflow, indicating that CS can be fed at 5% EE without compromising N metabolism.

Effects of heat stress and insulin sensitizers on pig adipose tissue

Heat stress (HS) negatively impacts several swine production variables, including carcass fat quality and quantity. Pigs reared in HS have more adipose tissue than energetically predicted, explainable, in part, by HS-induced hyperinsulinemia. Study objectives were to evaluate insulin's role in altering fat characteristics during HS via feeding insulin-sensitizing compounds. Forty crossbred barrows (113 ± 9 kg BW) were randomly assigned to one of five environment by diet treatments: 1) thermoneutral (TN) fed ad libitum (TNAL), 2) TN and pair-fed (TNPF), 3) HS fed ad libitum (HSAL), 4) HS fed ad libitum with sterculic oil (SO) supplementation (HSSO; 13 g/d), and 5) HS fed ad libitum with dietary chromium (Cr) supplementation (HSCr; 0.5 mg/d; Kemin Industries, Des Moines, IA). The study consisted of three experimental periods (P). During P0 (2 d), all pigs were exposed to TN conditions (23 ± 3 °C, 68 ± 10% RH) and fed ad libitum. During P1 (7 d), all pigs received their respective dietary supplements, were maintained in TN conditions, and fed ad libitum. During P2 (21 d), HSAL, HSSO, and HSCr pigs were fed ad libitum and exposed to cyclical HS conditions (28 to 33 °C, 58 ± 10% RH). The TNAL and TNPF pigs remained in TN conditions and were fed ad libitum or pair-fed to their HSAL counterparts. Rectal temperature (TR), respiration rate (RR), and skin temperature (TS) were obtained daily at 0600 and 1800 h. At 1800 h, HS exposed pigs had increased TR, RR, and TS relative to TNAL controls (1.13 °C, 48 bpm, and 3.51 °C, respectively; P < 0.01). During wk 2 and 3 of P2, HSSO pigs had increased 1800 h TR relative to HSAL and HSCr (~0.40 and ~0.42 °C, respectively; P ≤ 0.05). Heat stress decreased ADFI and ADG compared to TNAL pigs (2.24 vs. 3.28 and 0.63 vs. 1.09 kg/d, respectively; P < 0.01) and neither variable was affected by SO or Cr supplementation. Heat stress increased or tended to increase moisture content of abdominal (7.7 vs. 5.9%; P = 0.07) and inner s.c. (11.4 vs. 9.8%; P < 0.05) adipose depots compared to TNAL controls. Interestingly, TNPF pigs also had increased adipose tissue moisture content and this was most pronounced in the outer s.c. depot (15.0 vs. 12.2%; P < 0.01) compared to TNAL pigs. Heat stress had little or no effect on fatty acid composition of abdominal, inner, and outer s.c. adipose tissue depots. In summary, the negative effects of HS on fat quality do not appear to be fatty acid composition related, but may be explained by increased adipose tissue moisture content.