Independent effects of dietary linoleic and linolenic fatty acids on the conjugated linoleic acid content of cows’ milk

Feeding Corn Silage or Grass Hay as Sole Dietary Forage Sources: Overall Mechanism of Forages Regulating Health-Promoting Fatty Acid Status in Milk of Dairy Cows

Different dietary forage sources regulate health-promoting fatty acids (HPFAs), such as conjugated linoleic acids (CLAs) and omega-3 polyunsaturated fatty acids (n-3 PUFAs), in the milk of lactating cows. However, the overall mechanism of forages regulating lipid metabolism from the gastrointestinal tract to the mammary glands (MGs) is not clear. Three isocaloric diets that contained (1) 46% corn silage (CS), (2) a mixture of 23% corn silage and 14% grass hays (MIX), and (3) 28% grass hays (GH) as the forage sources and six cannulated (rumen, proximal duodenum, and terminal ileum) lactating cows were assigned to a double 3 × 3 Latin square design. Our results show that a higher proportion of grass hay in the diets increased the relative contents of short-chain fatty acids (SCFAs), CLAs, and n-3 PUFAs. The lower relative content of SCFA in the milk of CS was predominantly due to the reduction in acetate production in the rumen and arteriovenous differences in the MG, indicating that the de novo synthesis pathways were inhibited. The elevated relative contents of total CLA and n-3 PUFA in the milk of GH were attributed to the increases in apparent intestinal digestion and arteriovenous differences in total CLA and n-3 PUFA, together with the higher Δ⁹-desaturase activity in the MG. In conclusion, this study provides an overall mechanism of dietary forages regulating HPFA status in the milk of dairy cows.

Short-Term Variations of C18:1 Trans Fatty Acids in Plasma Lipoproteins and Ruminal Fermentation Parameters of Non-Lactating Cows Subjected to Ruminal Pulses of Oils

The objective of this study was to evaluate short-term variations of trans fatty acids (TFA) in plasma lipoproteins and ruminal fermentation parameters of non-lactating cows subjected to ruminal pulses of vegetable oils. Three non-lactating, non-pregnant Holstein cows, each with a ruminal cannula, were arranged in a 3 × 3 Latin square design with three-day pulsing periods and four-day washout intervals between treatments. Cows were treated with single ruminal pulses of: (1) control (skimmed milk (SM); 500 mL); (2) soybean oil (SO; 250 g/d in 500 mL of SM) and (3) partially-hydrogenated vegetable oil (PHVO; 250 g/d in 500 mL of SM). Time changes after infusion in TFA contents were only observed for plasma C18:1 trans-4, trans-5 and trans-12, and high-density lipoprotein fraction C18:1 trans-9. After ruminal pulses, concentration of acetate decreased linearly; molar concentrations of propionate and valerate increased linearly; molar concentrations of butyrate and isovalerate changed quadratically and were greater at 1 h than at other times. There was an accumulation of several C18:1 TFA in plasma and lipoproteins, especially on the third day of pulsing. Overall, naturally occurring C18:1 TFA isomers (produced during ruminal biohydrogenation of SO) and preformed TFA (supplied by PHVO) elicited differential TFA partitioning and transport in plasma and lipoproteins.

Association of leptin genotype with growth performance, adipocyte cellularity, meat quality, and fatty acid profile in beef steers fed flaxseed or high-oleate sunflower seed diets with or without triticale dried distiller's grains

Leptin genotypes can be identified as homozygous normal (CC), homozygous mutant (TT), and heterozygous (CT) based on a single-nucleotide polymorphism in exon 2 of the leptin gene, which has been associated with feed intake and fat deposition in cattle. The experiment was designed as 2 × 2 × 2 factorial with three main factors: (1) genotype (CT or TT) and diets fed 2) with or without triticale dried distiller's grains with solubles (DDG), and 3) with either flaxseed (FS) or high-oleate sunflower seed (SS). Evaluations included growth performance, subcutaneous fat deposition, adipocyte cellularity, meat quality, and fatty acid (FA) profile of various depots. Beef steers (n = 40, 459 ± 31 kg) of either CT or TT genotypes were housed in individual pens with ad libitum access to one of the four diets: 75% steam-rolled barley + 10% barley silage with 10% FS or SS (non-DDG diets, NDG) and 46.5% barley + 10% barley silage + 30% DDG, with 8.5% FS or SS, all on a dry matter basis. Growth performance, ultrasound subcutaneous fat thickness, rib eye area (REA), and plasma FA were measured prior to and during the finishing period. At slaughter, samples of subcutaneous fat, perirenal fat, and Longissimus thoracis (LT) muscle were collected for FA analysis and carcass and meat quality were measured. Compared with CT cattle, TT tended to have less (P = 0.06) C18:2-c9,t11 (rumenic acid) in plasma and subcutaneous fat and a greater proportion (P < 0.05) of C18:0 in subcutaneous, perirenal, and LT fat. Cattle with TT genotype also tended (P < 0.1) to have more total saturated and less unsaturated (USFA) and monounsaturated fats (MUFA) and had less (P = 0.04) linoleic acid in LT. Ultrasound fat thickness, REA, and average diameter of adipocytes in subcutaneous fat at 12 wk were not affected (P > 0.39) by genotype. Generally, carcass and meat quality were similar (P > 0.1) among diets, although adding FS tended to increase (P = 0.06) total USFA of subcutaneous fat including omega-3 FA (P < 0.001). For the high-fat diets evaluated, CT cattle would have more potential to produce beef with enhanced health benefits than would TT cattle.

Effect of forage brassicas in dairy cow diets on the fatty acid profile and sensory characteristics of Chanco and Ricotta cheeses

In humid temperate regions, forage turnip (Brassica rapa ssp. rapa) and forage rape (Brassica napus ssp. biennis) are common fodder crops used for dairy cattle during the summer season. However, there is little scientific information regarding the use of brassicas and their effect on the fatty acid (FA) profile in blood, milk, and milk products. The aim of this study was to evaluate the effect of forage brassica supplementation in dairy cows on the FA profile of blood plasma, milk, and cheese, and on the sensory characteristics of Chanco and Ricotta cheeses. Twelve multiparous dairy cows (Holstein Friesian) were housed and submitted to a 3 × 3 replicated (n = 3) Latin square design with 3 treatments (control, turnip, or rape) in 3 periods of 21 d each (14 d of diet adaptation and 7 d of measurements). The control diet consisted of 16.20 kg of grass silage (Lolium perenne), 2.25 kg of soybean bran, and 2.25 kg of commercial concentrate, all on a dry matter (DM) basis. In the treatments with forage brassicas, 24.15% of the total DM was replaced by turnip or rape; thus, they consisted of 12.25 kg of silage, 2.25 kg of soybean bran, 1.2 kg of concentrate, and 5 kg of turnip or rape (DM basis). A principal components analysis was performed on the results of the cheese sensory evaluation. Supplementation with turnip or rape modified the profile of FA in blood plasma and milk, increasing the saturated fraction, mainly short- and medium-chain FA, and decreasing the mono- and polyunsaturated FA. In the sensory evaluation, diet did not affect any of the 18 attributes evaluated. However, in the principal components analysis, cheeses made with milk from animals fed turnip and rape were differentiated by increased odor, flavor, spiciness, bitterness, and acidity. Overall, brassicas can be used as an alternative forage source with no negative effects on sensory characteristics of cheeses.

The relationship between plasma β-hydroxybutyric acid and conjugated linoleic acid in milk as a biomarker for early diagnosis of ketosis in postpartum Polish Holstein-Friesian cows

Background

The aim of this study was to investigate the association between plasma β-hydroxybutyric acid (BHBA) and conjugated linoleic acid in postpartum Polish Holstein-Friesian (PHF) cows. The experiment was carried out at an experimental dairy farm, where a herd of approximately 350 cows was kept. Samples were taken at six time points: between days 5–7, 8–14, 15–21, 22–28, 29–35, and 36–42, resulting in 510 samples of both milk and blood. The cows involved in the experiment were divided into two groups – ketotic and healthy – by taking into account general health symptoms, blood serum BHBA, and non-esterified fatty acids (NEFA) concentration at 5–7 days postpartum.

Results

In the first week of lactation, at 5–7 day in milk (DIM), the study showed a 53% lower level of C18:2 cis-9 trans-11 (CLA9) and an 80% lower level of C18:2 trans-10 cis-12 (CLA10) in cows with diagnosed ketosis compared to healthy cows. In the second week of lactation (8–14 DIM), a 34% lower level of CLA9 and a 54% lower level of CLA10 was found in the group of cows with BHBA levels > 1.2 mmol/L. Additionally, Pearson correlation analysis showed significant negative correlation between BHBA x CLA9 and BHBA x CLA10 in the first week of lactation: − 0.732and − 0.821, respectively.

Conclusion

The study shows that that both CLA9 and CLA10 can be used as markers for the early diagnosis of elevated blood levels of BHBA in postpartum Polish Holstein-Friesian cows.

Effect of Feeding Cows with Unsaturated Fatty Acid Sources on Milk Production, Milk Composition, Milk Fatty Acid Profile, and Physicochemical and Sensory Characteristics of Ice Cream

Simple Summary

The objective of this study was to evaluate the effects of supplementation of dairy cows’ diets with different fatty acid (FA) sources on milk production, milk composition, milk fatty acid profile, and physicochemical and sensory characteristics of ice cream. Supplementation (3% dry matter (DM)) of diets with soybean oil (SO) and fish oil (FO) did not have detrimental effects on milk production, milk composition, or ice cream physicochemical and sensory characteristics. From a human standpoint, SO and FO improved the FA profile of milk.

Abstract

The objective of this study was to evaluate the effects of supplementation of dairy cows with different fatty acid sources (soybean oil (SO) and fish oil (FO)) on milk production, milk composition, milk fatty acid profile, and physicochemical and sensory characteristics of ice cream. During 63 days, fifteen Holstein cows averaging 198 ± 35 days in milk were assigned to three groups: control diet with no added lipid (n = 5 cows); and supplemented diets with SO (n = 5 cows; unrefined SO; 30 g/kg DM) or FO (n = 5 cows; FO from unrefined salmon oil; 30 g/kg DM). Milk production, milk fat, and milk protein were not affected by treatments. Saturated fatty acids in milk fat were decreased with SO and FO compared with control. C18:2 cis-9, cis-12 was increased with SO whereas C18:2 cis-9, trans-11, C20:3n-3, C20:3n-6, C20:5n-3, and C22:6n-3 were the highest with FO. Draw temperature and firmness were higher in SO compared to control and FO ice creams. Melting resistance was higher in FO compared with control and SO ice creams. Supplementation of cow diets with SO and FO did not have detrimental effects on milk production, or ice cream physicochemical and sensory characteristics.

Optimising Milk Composition

During recent decades, the UK dairy industry has had to adjust to the introduction of milk quotas in 1984, the deregulation of milk markets in 1994, and accommodate changes in the demand for dairy products. The combination of these factors, in addition to Bovine Spongiform Encephalopathy and Foot and Mouth disease, and a fall in milk price has inevitably resulted in a restructuring of the industry, but also reinforced the need for all sectors of the industry to respond to the prevailing economic climate and changes in consumer preferences.

Estimation of genetic variation in A9-desaturase enzyme activity in dairy cows

The ▵9-desaturase enzyme adds a cis-9 double bond to fatty acids in adipose and mammary tissue. In the mammary gland, this reaction converts C14:0 to C14:1, C16:0 to C16:1, C18:0 to cis-9 C18:1 (oleic acid), and trans- 11 C18:1(vaccenic acid) to cis-9, trans- 11 conjugated linoleic acid (CLA). Oleic acid is of interest in human nutrition as a component of the “Mediterranean diet” and CLA has been shown to have numerous health benefits. Conversion of vaccenic acid to CLA in the mammary gland accounts for 75-80% of CLA found in milk (Lock and Garnsworthy, 2002), but activity of the Δ9-desaturase enzyme varies among individual cows irrespective of dietary manipulations (Lock and Garnsworthy, 2003), suggesting that it may have a genetic component. The objective of this study was to estimate the genetic variation in Δ9-desaturase activity in dairy cows using milk fatty acid profiles.

Fatty acid profile in vertical strata of elephant grass subjected to intermittent stocking

The milk and meat from animals with a pasture-based diet have higher proportions of CLA and C18:3 and lower omega-6:omega-3 ratios than products from animals with diets based on corn silage and concentrate. However, most of the published studies have evaluated fatty acid profiles in temperate climate grasses and the literature with tropical grasses is scarce. Thus, the aim of this study was to evaluate the morphological and fatty acid compositions in the vertical strata of elephant grass (Pennisetum purpureum Schum.) swards subjected to grazing heights (90 or 120 cm pre-grazing heights) and levels of defoliation (50% or 70% removal of the initial pre-grazing height). There were no interactions among pre-grazing height, the level of defoliation and grazing stratum. However, higher proportion of C18:3 (58% and 63%) was found in the 90-cm swards and in the half upper stratum. A higher proportion of C18:3 was associated with a higher leaf proportion and crude protein content. Thus, the upper stratum of sward or a grazing management scheme (e.g. first-last stocking) resulting in a higher proportion of leaves and crude protein both provide higher proportions of C18:3 to animals grazing in elephant grass swards.

Effect of finishing system (feedlot or pasture), high-oil maize, and copper on conjugated linoleic acid and other fatty acids in muscle of finishing steers

Sixty Angus steers (413 ± 8.0 kg) were used to determine the effects of copper (Cu), maize type, and finishing system (confinement v. pasture) on performance, carcass characteristics, and fatty acid composition of longissimus muscle in steers. Steers in confinement were given individually high concentrate diets containing either typical or high-oil maize, using Calan gate feeders. Steers grazing pasture (tall fescue) were maintained in four pastures with each pasture containing five steers. Salt was used to limit concentrate intake in pasture steers to approximately 0.6 of that observed in confinement steers. One half of the steers in each treatment received a CuO needle bolus at the initiation of the study while the remaining steers received no supplemental Cu. Equal numbers of steers per treatment were harvested after 91, 112 or 133 days on food. Rate of gain was lower (P < 0.01; 1.2 v. 1.6 kg/day) for pasture-fed steers compared with steers receiving typical maize. Cu supplementation increased (P < 0.05) ADG in steers given typical maize (1.8 v. 1.5 kg/day) and those on pasture (1.3 v. 1.1 kg/day) but not in steers given high-oil maize diets (1.5 v. 1.5 kg/day). Gain, dry-matter intake and gain/food did not differ between steers given typical or high-oil maize. Plasma cholesterol concentrations were lower (P < 0.01) in steers given typical maize relative to steers given high-oil maize. Steers receiving a Cu bolus had higher plasma (P < 0.05) and liver (P < 0.01) Cu concentrations than steers not receiving a Cu bolus. Steers receiving typical maize had lower (P < 0.05) liver Cu concentrations than steers receiving high-oil maize. Steers finished on pasture with limited concentrate had conjugated linoleic acid (CLA) concentrations in longissimus muscle that were approximately three times higher (P < 0.01) than steers given typical maize. Cu supplementation tended (P < 0.10) to increase muscle CLA. Longissimus muscle from pasture-fed steers was lower (P < 0.01) in C16: 0 and higher (P < 0.05) in C10: 0, C17: 0, C18: 3, C20: 3 and total polyunsaturated fatty acids than steers given typical maize. Muscle C18: 1 trans and C17: 0 tended to be reduced (P < 0.10) by Cu supplementation. These results indicate that finishing cattle on pasture with limited grain increases CLA in longissimus muscle and that Cu supplementation also alters the fatty acid composition of muscle.

Effect of Supplementing Diets of Anglo-Nubian Goats with Soybean and Flaxseed Oils on Lactational Performance

We studied the effect of soybean or flaxseed oil feeding in the diets of lactating Anglo-Nubian goats. A total of 20 goats (33.6 ± 0.6 kg) were divided into four treatments and fed a basal diet of berseem clover and concentrates (40:60 DM basis; control) or the control diet supplemented with either 20 mL/day of flaxseed oil or soybean oil or 10 mL of soybean oil plus 10 mL of flaxseed oil per day for 12 weeks (i.e., 22 to 23 g per kg of DM intake). Oil inclusion decreased ruminal pH (P < 0.05), and acetate but increased (P < 0.05) total volatile fatty acids and molar proportion of propionate and blood glucose (P < 0.01). In addition, increased milk yield and decreased milk-fat contents were evident (P < 0.05) with oil supplementation. Diets containing oil increased (P < 0.05) unsaturated fatty acids (FA), conjugated linoleic acid, and the athrogenicity index of milk fat but decreased saturated FA concentrations. It is concluded that soybean-oil or flaxseed-oil supplementation of goats at 20 mL/day increased feed utilization and milk production.

Effectiveness of rubber seed oil and flaxseed oil to enhance the α-linolenic acid content in milk from dairy cows

This experiment was conducted to investigate effect of rubber seed oil compared with flaxseed oil when fed alone or in combination on milk yield, milk composition, and α-linolenic acid (ALA) concentration in milk of dairy cows. Forty-eight mid-lactation Holstein dairy cows were randomly assigned to 1 of 4 treatments according to a completely randomized design. Cows were fed a basal diet (control; CON) or a basal diet supplemented with 4% rubber seed oil (RO), 4% flaxseed oil (FO), or 2% rubber seed oil plus 2% flaxseed oil (RFO) on a dry matter basis for 9 wk. Feed intake, milk protein percentage, and milk fat levels did not differ between the treatments. Cows fed the RO, FO, or RFO treatments had a higher milk yield than the CON group (up to 10.5% more), whereas milk fat percentages decreased. Compared with the CON, milk concentration of ALA was substantially higher in cows receiving RO or RFO, and was doubled in cows receiving FO. The ALA yield (g/d) increased by 31.0, 70.3, and 33.4% in milk from cows fed RO, FO, or RFO, respectively, compared with the CON. Both C18:1 trans-11 (vaccenic acid) and C18:2 cis-9,trans-11 (conjugated linoleic acid; CLA) levels were higher in cows fed added flaxseed or rubber seed oil. The CLA yield (g/d) increased by 336, 492, and 484% in cows fed RO, FO, or RFO, respectively, compared with the CON. The increase in vaccenic acid, ALA, and CLA was greater in cows fed RFO than in cows fed RO alone. Compared with the CON, the milk fat from cows fed any of the dietary supplements had a higher concentration of unsaturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids; conversely, the saturated fatty acids levels in milk fat were 30.5% lower. Insulin and growth hormones were not affected by dietary treatments; however, we noted an increase in both cholesterol and nonesterified fatty acids levels in the RO, FO, or RFO treatments. These results indicate that rubber seed oil and flaxseed oil will increase milk production and the concentration of functional fatty acids (ALA, vaccenic acid, and CLA) in milk fat while decreasing the content of saturated fatty acids.

Comparison on the fatty acid profiles of liver, subcutaneous fat and muscle from feedlot steers finished on diets supplemented with or without cinnamaldehyde or monensin

BACKGROUND

Cinnamaldehyde (CIN) is the main active component of cinnamon (Cinnamomum cassia) oil and has been tested as alternative feed additive in cattle production. Little information was available on the effect of dietary CIN in comparison to monensin (MO) on beef fatty acid (FA) profile. This study analyzed FA profiles of liver, subcutaneous fat and pars costalis diaphragmatis (PCD) muscle obtained from steers (n = 70) finished on diets: control, a barley grain-silage feedlot diet; 330 mg/head.day MO; and 400, 800 or 1600 mg/head.day CIN treatments.

RESULTS

Inclusion of MO or CIN did not affect total saturated, unsaturated, polyunsaturated FA and individual FA in the various tissues with exceptions that proportion of palmitic acid in PCD muscle was increased by 800 mg/steer.day CIN (P < 0.05). There were positive correlations (P < 0.05) on oleic, linoleic, conjugated linoleic acid (CLA)-c9,t11 and 18:1-t10 between the subcutaneous fat and PCD muscle, and on α-linolenic acid, CLA-c9,t11 and 18:1-t10 between PCD muscle and liver, whereas correlations on the FA between the subcutaneous fat and liver were not significant except for 18:1-t10 (P < 0.01).

CONCLUSION

The results indicate that the supplementation of CIN and MO to feedlot diet has limited effect on beef FA profiles.

Short communication: Chemical composition, fatty acid composition, and sensory characteristics of Chanco cheese from dairy cows supplemented with soybean and hydrogenated vegetable oils

Lipid supplements can be used to alter fatty acid (FA) profiles of dairy products. For Chanco cheese, however, little information is available concerning effects of lipid supplements on sensorial properties. The objective of this study was to examine effects of supplementation of dairy cow diets with soybean (SO) and hydrogenated vegetable (HVO) oils on chemical and FA composition of milk and cheese and sensory characteristics of cheese. Nine multiparous Holstein cows averaging 169±24d in milk at the beginning of the study were used in a replicated (n=3) 3×3 Latin square design that included 3 periods of 21d. All cows received a basal diet formulated with a 56:44 forage:concentrate ratio. Dietary treatments consisted of the basal diet (control; no fat supplement), and the basal diet supplemented with SO (unrefined oil; 500g/d per cow) and HVO (manufactured from palm oil; 500g/d per cow). Milk fat yield was lower with HVO compared with control and SO. Cheese chemical composition and sensory profile were not affected by dietary treatment. Vaccenic (C18:1 trans-11) and oleic (C18:1 cis-9) acids were higher for SO than for control and HVO. Compared with control and HVO, SO decreased saturated FA and increased monounsaturated FA. The thrombogenic index of milk and cheese produced when cows were fed SO was lower than when cows were fed on control and HVO. The outcome of this study showed that, compared with control and HVO, supplementing dairy cow diets with SO improves milk and cheese FA profile without detrimental effects on the chemical composition of milk and cheese and the sensory characteristics of cheese.

Impact of calving seasons and feeding systems in western Canada. II. Meat composition and organoleptic quality of steaks

Durunna, O. N., Block, H. C., Iwaasa, A. D., Scott, S. L., Robins, C., Khakbazan, M., Dugan, M. E. R., Aalhus, J. L., Aliani, M. and Lardner, H. A. 2014. Impact of calving seasons and feeding systems in western Canada. II. Meat composition and organoleptic quality of steaks. Can. J. Anim. Sci. 94: 583–593. Fatty acid profiling, meat and organoleptic quality assessments were conducted on 160 carcasses of crossbred steers born into one of two calving systems and later assigned to one of two postweaning feeding systems. The steers were weaned from either an early calving or late calving system and later assigned to either a rapid-gain feeding (RF) or a slow-gain feeding (SF) system. The RF steers received a silage–hay diet during the backgrounding period prior to finishing, while the SF steers received a hay diet at backgrounding and then grazed alfalfa–meadow bromegrass pasture and annual cereal swaths prior to finishing. All treatment groups received a conventional diet during finishing until the steers attained a target backfat thickness or body weight. Fatty acid analyses were conducted on longissimus dorsi muscle (LDM) and subcutaneous fat samples. Other analyses included LDM composition, tenderness and taste panel evaluations. Total saturated fatty acid was greater (P<0.02) in samples from RF steers, while total monounsaturated fatty acid was greater (P<0.01) in SF steers. The SF steers had greater (P<0.01) conjugated linoleic acid concentration. There was no main or interaction effect (P>0.05) on beef aroma, flavour and tenderness but the SF steaks had lower (P=0.02) cooking losses than RF steaks. The SF strategy has the potential to create a value chain that would lead to finished steers with higher backfat omega-3, conjugated linoleic acid and trans vaccenic acid and less cooking moisture losses.

Subcutaneous adipose fatty acid profiles and related rumen bacterial populations of steers fed red clover or grass hay diets containing flax or sunflower-seed

Steers were fed 70∶30 forage∶concentrate diets for 205 days, with either grass hay (GH) or red clover silage (RC), and either sunflower-seed (SS) or flaxseed (FS), providing 5.4% oil in the diets. Compared to diets containing SS, FS diets had elevated (P<0.05) subcutaneous trans (t)-18:1 isomers, conjugated linoleic acids and n-6 polyunsaturated fatty acid (PUFA). Forage and oilseed type influenced total n-3 PUFA, especially α-linolenic acid (ALA) and total non-conjugated diene biohydrogenation (BH) in subcutaneous fat with proportions being greater (P<0.05) for FS or GH as compared to SS or RC. Of the 25 bacterial genera impacted by diet, 19 correlated with fatty acids (FA) profile. Clostridium were most abundant when levels of conjugated linolenic acids, and n-3 PUFA's were found to be the lowest in subcutaneous fat, suggestive of their role in BH. Anerophaga, Fibrobacter, Guggenheimella, Paludibacter and Pseudozobellia were more abundant in the rumen when the levels of VA in subcutaneous fat were low. This study clearly shows the impact of oilseeds and forage source on the deposition of subcutaneous FA in beef cattle. Significant correlations between rumen bacterial genera and the levels of specific FA in subcutaneous fat maybe indicative of their role in determining the FA profile of adipose tissue. However, despite numerous correlations, the dynamics of rumen bacteria in the BH of unsaturated fatty acid and synthesis of PUFA and FA tissue profiles require further experimentation to determine if these correlations are consistent over a range of diets of differing composition. Present results demonstrate that in order to achieve targeted FA profiles in beef, a multifactorial approach will be required that takes into consideration not only the PUFA profile of the diet, but also the non-oil fraction of the diet, type and level of feed processing, and the role of rumen microbes in the BH of unsaturated fatty acid.

Association of protein expression in isolated milk epithelial cells and cis-9, trans-11 conjugated linoleic acid proportions in milk from dairy cows

BACKGROUND

The effects of the individual variation among dairy cows on the synthesis of cis-9, trans-11 conjugated linoleic acid (CLA) are still not well characterised. Therefore, the protein expression profiles of isolated milk epithelial cells (MECs) were detected by two-dimensional electrophoresis and their correlation with the various proportion of cis-9, trans-11 CLA were evaluated.

RESULTS

Although animals were offered the same diet, the proportion of cis-9, trans-11 CLA in group High (1.02 ± 0.10%) was twice as high as that in group Low (0.59 ± 0.14%) (P < 0.05). MECs with the characteristics of native epithelial cells were successfully isolated from the milk and these cells had no obvious RNA degradation or were hardly contaminated with leucocytes or blood red cells. Moreover, the protein expression pattern of cathelicidin 5 in isolated MECs was positive, whereas annexin I (confirmed by real-time polymerase chain reaction), ZW10 interactor and κ-casein were negatively related to the proportion of cis-9, trans-11 CLA in the milk fat.

CONCLUSION

The varied individual content of cis-9, trans-11 CLA in cows may be associated with annexin I. These findings may provide some theoretical basis for studies concerning the effects of the individual variation among dairy cows of the synthesis of cis-9, trans-11 CLA. © 2013 Society of Chemical Industry.

Effect of dietary inclusion of triticale dried distillers' grain and oilseeds on quality and fatty acid profile of meat from feedlot steers

This study compared carcass, meat quality and fatty acid profiles of longissimus thoracis (LT) from feedlot cattle fed barley grain with or without oilseed (OS). Six diets containing no oilseed (No-OS), 10% ground flaxseed (FS), 10% high oleate sunflower seeds (SS) with or without 30% triticale dried distiller's grain (DDGS) were prepared. Feeding DDGS increased chroma at 24 and 144 h post mortem. Feeding FS increased weight% of LT PUFA (P<0.05) compared to No-OS or SS. An OS by DDGS interaction occurred for 18:3n-3 (P<0.05) where FS increased weight% of 18:3n-3 (P<0.05), a response accentuated (P<0.05) by DDGS. Feeding DDGS increased weight% of LT 18:2n-6 (P<0.05), but neither OS nor DDGS affected conjugated linoleic acid (CLA, t7,c9 &c9,t11-18:2). Feeding FS increased weight% of n-3 FA, and both FS and SS increased t10-18:1 with no effect on CLA or t11-18:1. Combination feeding of DDGS and FS further increased weight% of n-3 FA and tempered increases in t10-18:1 with no effect on CLA or t11-18:1. The findings suggest a new strategy to increase beef omega-3 fatty acids efficiently through inclusion of a combination of DDGS and FS in feedlot diet.

Effect of high dietary levels of canola meal on growth performance, carcass quality and meat fatty acid profiles of feedlot cattle

He, M. L., Gibb, D., McKinnon, J. J. and McAllister, T. A. 2013. Effect of high dietary levels of canola meal on growth performance, carcass quality and meat fatty acid profiles of feedlot cattle. Can. J. Anim. Sci. 93: 269–280. This study investigated the effect of substituting canola meal (CM) for barley grain on growth performance, carcass quality and meat fatty acid (FA) profiles of feedlot cattle. Cross bred calves (n=140; 285±27 kg) were individually fed diets comprised of a barley grain based concentrate (including 5% supplement) and barley silage at ratios of 45:55 and 92:8 (DM basis) during growing and finishing periods, respectively. Pressed CM from Brassica napus, containing 11.4% residual oil and solvent-extracted CM derived from B. napus or Brassica juncea canola seed were compared. Canola meal was substituted for 0 (control), 15, or 30% barley grain (DM basis) in both growing and finishing diets. Regardless of diet, cattle did not differ (P>0.05) in average daily gain in either the growing or finishing period. For the overall feeding period, inclusion of 30% CM increased (P<0.01) DMI of cattle compared with 15% CM groups, but reduced (P<0.05) gain: feed (G:F) as compared with control and 15% B. juncea and 15% pressed CM. Gain: feed of cattle fed CM was also reduced (P<0.05) during the finishing period as compared with the control diet with this reduction being more notable at the 30% level. Carcass quality and incidence of liver abscesses were not affected (P>0.05) by inclusion of CM. Inclusion of 30% pressed CM resulted in higher (P<0.05)%FAME of total polyunsaturated fatty acid, n-3, alpha-linolenic acid and conjugated linoleic acid (CLA), and a decrease (P<0.05) in n-6/n-3 ratio in the pars costalis diaphragmatis muscle as compared with the control diet. In conclusion, inclusion of CM did not alter the growth performance or G:F of beef cattle during the growing period, but did lower G:F during the finishing period. The inclusion of 15 or 30% solvent-extracted CM did not alter carcass quality, whereas 30% pressed CM increased the levels of desirable fatty acids (i.e., n-3 and CLA) in beef.

Changes in fatty acid composition of various full fat crushed oilseeds and their free oils when incubated with rumen liquor in vitro

The fatty acid pattern of dietary lipids can be modified during rumen biohydrogenation (BH). The objective of the present study was to assess changes in the FA pattern of different oilseed products supplied either as crushed full fat oilseed or as free oil after in vitro incubation with buffered rumen liquor. The FA patterns were determined at the beginning and compared with those measured after 24 h of incubation. The contents of fatty acids (FA) < C18 increased (p < 0.05) in nearly all treatments, eventually due to microbial de novo synthesis and fermentation of carbohydrates and proteins during incubation. In contrast, the contents of the dominating C18 FA, (oleic acid - C18:1c9, linoleic acid - C18:2c9,12, linolenic acid - C18:3c9,12,15) were reduced due to BH, resulting in the accumulation of characteristic BH intermediates, such as conjugated linoleic acid (CLA) isomer C18:2c9t11 (rumenic acid). However, both for crushed full fat oilseeds and their free oils the process of BH was not completed at the end of incubation. The disappearance was highest for C18:3c9,12,15, followed by C18:2c9,12 and C18:1c9. The rate of BH of unsaturated FA was higher in the crushed form compared to the oil form. Higher amounts of BH intermediates accumulated in the crushed form. Obviously, the physical form affects the degree of BH in vitro. The current results suggest that feeding crushed full fat seeds instead of their free oils to dairy cows might stimulate the formation of beneficial BH intermediates such as CLA in the rumen.

Milk fatty acid composition and production performance of Danish Holstein and Danish Jersey cows fed different amounts of linseed and rapeseed

Fat supplements are used in diets for dairy cows to increase energy intake and milk production and the fatty acid composition of the feed affects milk fatty acid composition. A total of 74 Danish Holstein and 41 Danish Jersey cows were divided into 4 groups and the cows within each group were fed a mixed ration supplemented with 0, 3.5, 6.8, or 10.2% of dry matter of a linseed:rapeseed (1:3) mixture during lactation wk 6 to 30. Milk yield, fat, and lactose contents were not affected by treatments for Danish Holsteins, whereas these parameters increased when increased amounts of oilseeds were fed to Danish Jerseys. For both breeds, milk protein content decreased when increased amounts of oilseeds were fed. The milk fatty acid composition showed higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty acids in milk fat from Danish Jerseys compared with Danish Holsteins. Increased amounts of oilseeds in feed increased milk fat concentration of all C18 fatty acids except C18:2 n-6, whereas the content of C6 to C14, C11 to C17, and in particular, C16, decreased. This effect was more pronounced for Danish Holsteins than for Danish Jerseys. The apparent recovery of C18:2 n-6 and C18:3 n-3 decreased when increased amounts of oilseeds were fed; however, this was most likely due to increased amounts of fatty acid from feed used for other energy demands than milk production. It was concluded that up to 6.8% of oilseed supplementation can be fed without production problems and, in many cases, with positive production responses, including an improved milk fatty acid profile.

Effects of feeding different linseed sources on omasal fatty acid flows and fatty acid profiles of plasma and milk fat in lactating dairy cows

The aim of this experiment was to study the effects of feeding different linseed sources on omasal fatty acid (FA) flows, and plasma and milk FA profiles in dairy cows. Four ruminally cannulated lactating Holstein-Friesian cows were assigned to 4 dietary treatments in a 4×4 Latin square design. Dietary treatments consisted of supplementing crushed linseed (CL), extruded whole linseed (EL), formaldehyde-treated linseed oil (FL) and linseed oil in combination with marine algae rich in docosahexaenoic acid (DL). Each period in the Latin square design lasted 21 d, with the first 16 d for adaptation. Omasal flow was estimated by the omasal sampling technique using Cr-EDTA, Yb-acetate, and acid detergent lignin as digesta flow markers. The average DM intake was 20.6 ± 2.5 kg/d, C18:3n-3 intake was 341 ± 51 g/d, and milk yield was 32.0 ± 4.6 kg/d. Milk fat yield was lower for the DL treatment (0.96 kg/d) compared with the other linseed treatments (CL, 1.36 kg/d; EL, 1.49 kg/d; FL, 1.54 kg/d). Omasal flow of C18:3n-3 was higher and C18:3n-3 biohydrogenation was lower for the EL treatment (33.8 g/d; 90.9%) compared with the CL (21.8 g/d; 94.0%), FL (15.5 g/d; 95.4%), and DL (4.6 g/d; 98.5%) treatments, whereas whole-tract digestibility of crude fat was lower for the EL treatment (64.8%) compared with the CL (71.3%), FL (78.5%), and DL (80.4%) treatments. The proportion of C18:3n-3 (g/100 g of FA) was higher for the FL treatment compared with the other treatments in plasma triacylglycerols (FL, 3.60; CL, 1.22; EL, 1.35; DL, 1.12) and milk fat (FL, 3.19; CL, 0.87; EL, 0.83; DL, 0.46). Omasal flow and proportion of C18:0 in plasma and milk fat were lower, whereas omasal flow and proportions of biohydrogenation intermediates in plasma and milk fat were higher for the DL treatment compared with the other linseed treatments. The results demonstrate that feeding EL did not result in a higher C18:3n-3 proportion in plasma and milk fat despite the higher omasal C18:3n-3 flow. This was related to the decreased total-tract digestibility of crude fat. Feeding FL resulted in a higher C18:3n-3 proportion in plasma and milk fat, although the omasal C18:3n-3 flow was similar or lower than for the CL and EL treatment, respectively. Feeding DL inhibited biohydrogenation of trans-11,cis-15-C18:2 to C18:0, as indicated by the increased omasal flows and proportions of biohydrogenation intermediates in plasma and milk fat.

Triticale dried distillers' grain increases alpha-linolenic acid in subcutaneous fat of beef cattle fed oilseeds

This study investigated the effect of triticale dried distillers' grain with solubles (DDGS), flax (FS) and sunflower (SS) seed on growth and the fatty acid profile of subcutaneous (SQ) fat in individually housed steers (n = 15 per diet) fed ad libitum (DM basis); (1) control (CON) 90% barley grain + 10% barley silage; or substitution of barley grain for: (2) 30% DDGS; (3) 10% FS; (4) 30% DDGS + 8.5% FS; (5) 10% SS and (6) 30% DDGS + 8.5% SS. Oilseeds in the combination diets were reduced to maintain diet lipid levels below 9% DM and to determine if favorable changes in the fatty acid profile could be maintained or enhanced at reduced levels of oilseed. Plasma and SQ fat biopsies were collected at 0, 6, and 12 weeks. Inclusion of DDGS decreased (P < 0.05) average daily gain, feed conversion and backfat thickness. Feeding FS increased (P < 0.05) plasma ALA compared to CON and SS and consistently increased (P < 0.01) ALA and non-conjugated and non-methylene interrupted dienes (NCD), whereas SS tended to decrease ALA in fat. Inclusion of DDGS with FS further increased (P < 0.02) ALA and decreased (P < 0.05) NCD and 18:1-t10 in fat. The fact that the levels of n-3 fatty acids in SQ fat from steers fed DDGS + FS were higher than those obtained with FS alone, has obvious benefits to the practical cost of favorably manipulating fatty acid profiles in beef.

Fatty Acid Composition of Phospholipids and in the Central and External Positions of Triacylglycerol in Muscle and Subcutaneous Fat of Beef Steers Fed Diets Supplemented with Oil Containing n6 and n3 Fatty Acids While Undergoing One of Three 48 h Feed Withdrawal Treatments

This study was designed to determine the effects of dietary oil and feed withdrawal treatments on fatty acid composition of phospholipids of triacylglycerol in pars costalis diaphragmatis muscle and subcutaneous fat from the brisket. A 2 × 3 factorial experiment was conducted with crossbred steers with an initial body weight of 280.5 ± 5.8 kg. Steers were fed either a control or an oil containing diet where 5% of the control diet was replaced with an equal mixture sunflower and flax oil while undergoing one of three feed withdrawal treatments: no withdrawal, a single 48 h withdrawal before initiation of fattening at one year of age, or 48 h withdrawal at 8 wk intervals from weaning to initiation of fattening. At time of processing samples of muscle and fat were obtained and analyzed to determine fatty acid composition. Disproportionate distribution of the fatty acids was observed by diet, feed withdrawal regimen and whether the sample was from muscle or fat. Differences are discussed in detail, and our data suggests a special function for the fatty acids that accumulate in specific positions of the triacylglycerol due to treatment.

Inclusion of flaxseed in hay- and barley silage diets increases alpha-linolenic acid in cow plasma independent of forage type

Feeding flaxseed to cattle may be a means of increasing omega-3 fatty acid levels in ruminant products, but possible interactions with conserved forages have not been investigated. Twelve Holstein cows were used in a replicated 4 × 4 Latin Square experiment. Cows were fed one of four 50:50 forage:concentrate diets (DM basis): hay (hay control, HC), hay plus 15% ground flaxseed (hay-flaxseed, HF), barley silage (silage control, SC), and barley silage plus 15% ground flaxseed (silage-flaxseed, SF). Plasma concentrations of alpha-linolenic acid (ALA) did not differ between SC and HC diets. Flaxseed increased ALA (P < 0.05), but levels were not influenced by forage type. Flaxseed slightly increased 18:2n-6 (P < 0.05) and some n-6 and n-3 elongation and desaturation products, particularly arachidonic acid (ARA) and eicosapentaenoic acid (EPA). Flaxseed also increased C18:0 (P < 0.05) with this increase being greater (P < 0.01) for cows fed SF than HF. Feeding flaxseed also increased plasma C18:1-trans isomers (P < 0.01), predominantly vaccenic acid (VAA, 18:1-t11), with this increase being greater (P < 0.05) in cows fed HF than SF. Although conjugated linoleic acid (CLA) was increased (P < 0.001) with flaxseed it was not influenced by forage type (P = 0.06). Overall, feeding flaxseed increased plasma ALA, EPA, ARA and CLA independently of forage type. Feeding flaxseed with silage, however, resulted in more 18:0, while feeding flaxseed with hay resulted in greater accumulations of plasma 18:1-trans isomers mainly in the form of VAA.

Supplementation with whole cottonseed changes milk composition and milk fatty acid profile in dairy cows

Eight multiparous Holstein cows in mid lactation (average days in milking of 160 ± 40) were used in a replicated 4 by 4 Latin square design, each experimental period lasting 3 weeks, to determine the effects of whole cottonseed (WCS) treatment and dietary crude protein (CP) concentration on the profile of milk fatty acids. Each 3-week experimental period consisted of 2 weeks for ration adaptation followed by 1 week for data collection. The experimental diets consisted of: (1) Control (without WCS), 16% CP; (2) 20% WCS, 16% CP; (3) 20% WCS, 13% CP; and (4) 20% crushed WCS, 13% CP. Minerals and vitamin supplements were the same in all experimental diets. The WCS treatment led to increased DM intake, fat-corrected milk yield, fat concentration, proportion of long-chain fatty acids, unsaturated fatty acids and ratio of unsaturated to saturated fatty acids (P < 0.05). Decreased concentration of dietary CP from 16 to 13% (diet 2 compared with diet 3) led to a decrease in both milk yield and milk composition (P < 0.05). WCS crushed in diets with 13% CP (diet 4 compared with diet 3) increased (P < 0.05) the concentration of conjugated linoleic acid in milk fat. The results demonstrated that adding WCS to the diet of lactating cows improves both milk yield and milk fatty acid profile, particularly the proportion of conjugated linoleic acid.