Short communication: responses to increasing amounts of free alpha-linolenic acid infused into the duodenum of lactating dairy cows

Effect of Salvia sclarea L. extract on growth performance, antioxidant capacity, and immune function in lambs

The aim of this experiment is to explore the effects of salvia sclarea extract on the growth performance, apparent nutrient digestibility, antioxidant capacity, and immune function of lambs. Sixty female lambs (Chinese Merino sheep) aged 2 months and weighing 20 ± 2 kg were selected and randomly divided into five groups of twelve lambs in each. While the control group (CK) received only basal feed, the experimental group was supplemented with different concentrations of salvia sclarea extract in the basal feed at 0.04 mL/kg (group CL1), 0.08 mL/kg (group CL2), 0.12 mL/kg (group CL3), and 0.16 mL/kg (group CL4). The feeding period was 85 days, including 15 days of pre-feeding and 70 days of regular feeding. Body weight and feed intake were recorded during the test period, and blood was collected at the end of the test for the determination of immune and antioxidant indices. The results showed that the average daily gain and average daily feed intake of lambs were significantly increased in CL3 group compared to CK group (p < 0.05). Also, the apparent nutrient digestibility of crude protein and neutral detergent fiber was significantly increased (p < 0.05). The Dry matter, acid detergent fiber and Ether extract were not significantly different (p > 0.05). The serum levels of superoxide dismutase, catalase, glutathione peroxidase, and antioxidant capacity were significantly higher in the CL2, CL3, and CL4 groups compared to CK group, while malondialdehyde levels were significantly lower (p < 0.05). The serum levels of immune globulin A, immune globulin G, immune globulin M, interferon-γ, and interleukin-10 were significantly higher and the levels of tumor necrosis factor-α and interleukin-1β were significantly lower in the CL2, CL3, and CL4 groups (p < 0.05). In conclusion, the addition of salvia sclarea extract to the ration promotes growth performance and nutrient digestion in lambs. Improvement of immune response by increasing immunoglobulin and cytokine concentrations. And it enhances the antioxidant status by increasing the antioxidant enzyme activity in lambs.

Introduction

This study aimed to explore the effects of Salvia sclarea extract on the growth performance, apparent nutrient digestibility, antioxidant capacity, and immune function of the lambs.

Methods

Sixty female lambs (Chinese Merino sheep) aged 2 months and weighing 20 ± 2 kg were selected and randomly divided into five groups of 12 lambs each. The control group (CK) received only basal feed, whereas the experimental group was supplemented with different concentrations of salvia sclarea extract in the basal feed at 0.04, 0.08, 0.12, and 0.16 mL/kg (CL1, CL2, CL3, and CL4, respectively). The feeding period was 85 days, including 15 days of pre-feeding and 70 days of regular feeding. Body weight and feed intake were recorded during the test period, and blood was collected at the end of the test to determine immune and antioxidant indices.

Results

The results showed that the average daily weight gain and feed intake of the lambs were significantly higher in the CL3 group than in the CK group (p < 0.05). In addition, the apparent nutrient digestibility of crude protein and neutral detergent fiber increased significantly (p < 0.05). The dry matter, acid detergent fiber, and ether extract were not significantly different (p > 0.05). Serum levels of superoxide dismutase, catalase, and glutathione peroxidase and antioxidant capacity were significantly higher in the CL2, CL3, and CL4 groups than in the CK group, whereas malondialdehyde levels were significantly lower (p < 0.05). The serum levels of immune globulin immune globulin A, immune globulin G, immune globulin M, interferon-γ, and interleukin-10 were significantly higher and the levels of tumor necrosis factor-α and interleukin-1β were significantly lower in the CL2, CL3, and CL4 groups (p < 0.05).

Discussion

In conclusion, the addition of the S. sclarea extract to the diet promoted growth performance and nutrient digestion in lambs. Immune response was improved by increasing Ig and cytokine concentrations. It enhances antioxidant status by increasing antioxidant enzyme activity in lambs.

DHA-Rich Aurantiochytrium Biomass, a Novel Dietary Supplement, Resists Degradation by Rumen Microbiota without Disrupting Microbial Activity

We first sought to evaluate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA), on rumen fermentation and the resistance of DHA to degradation and biohydrogenation by rumen microbes through ex vivo fermentation experiments. Subsequently, we sought to quantify the diet-derived DHA content of milk and the impact of AURA on microbial composition and metabolism in a pilot feeding trial with rumen-cannulated dairy cows. To achieve our aims, rumen fluid from cannulated cows was used as inoculum, and the effect of AURA inclusion on fermentation ex vivo was examined. At doses corresponding to the amount of AURA recommended for commercial production animals, only ~10% of DHA was degraded or biohydrogenated by rumen microorganisms. The results show that feeding with AURA had no effect on either total bacterial density or short-chain fatty acid production. Real-time quantitative PCR analysis of the rumen fluid samples collected during a seven-week in vivo trial revealed that microbes related to lactic acid metabolism and methanogenesis were significantly suppressed by the AURA-supplemented diet. The DHA concentration in milk increased over 25-fold with the AURA-supplemented diet and dropped by 30–40% within one week of washout. The addition of A. limacinum biomass to dairy cow diets resulted in positive effects on rumen microbial composition with no adverse effect on fermentation activity. AURA-derived DHA was stable, with only modest degradation in the rumen, and was successfully deposited in milk. This is the first study to investigate the effect of supplementing the diet of dairy cows with a protist-based biomass, namely, on important rumen fermentation parameters and on DHA deposition in milk, using a combination of ex vivo and in vivo approaches.

Milk fat: opportunities, challenges and innovation

Milk fat is a high-value milk component that is processed mainly as butter, cheese, cream and whole milk powder. It is projected that approximately 35 million tonnes of milk fat will be produced globally by 2025. This surplus, enhances the need for diversification of milk fat products and the milk pool in general. Infant milk formula producers, for instance, have incorporated enzyme modified ("humanised") milk fat and fat globule phospholipids to better mimic human milk fat structures. Minor components like mono- and di-glycerides from milk fat are increasingly utilized as emulsifiers, replacing palm esters in premium-priced food products. This review examines the chemistry of milk fat and the technologies employed for its modification, fractionation and enrichment. Emerging processing technologies such as ultrasound, high pressure processing, supercritical fluid extraction and fractionation, can be employed to improve the nutritional and functional attributes of milk fat. The potential of recent developments in biological intervention, through dietary manipulation of milk fatty acid profiles in cattle also offers significant promise. Finally, this review provides evidence to help redress the imbalance in reported associations between milk fat consumption and human health, and elucidates the health benefits associated with consumption of milk fat and dairy products.

Effects of abomasal infusion of essential fatty acids together with conjugated linoleic acid in late and early lactation on performance, milk and body composition, and plasma metabolites in dairy cows

Rations including high amounts of corn silage are currently very common in dairy production. Diets with corn silage as forage source result in a low supply of essential fatty acids, such as α-linolenic acid, and may lead to low conjugated linoleic acid (CLA) production. The present study investigated the effects of abomasal infusion of essential fatty acids, especially α-linolenic acid, and CLA in dairy cows fed a corn silage-based diet on performance, milk composition, including fatty acid (FA) pattern, and lipid metabolism from late to early lactation. Rumen-cannulated Holstein cows (n = 40) were studied from wk 9 antepartum to wk 9 postpartum and dried off 6 wk before calving. The cows were assigned to 1 of 4 treatment groups. Cows were abomasally supplemented with coconut oil (CTRL, 76 g/d), linseed and safflower oil (EFA, 78 and 4 g/d; linseed/safflower oil ratio = 19.5:1; n-6/n-3 FA ratio = 1:3), Lutalin (CLA, 38 g/d; BASF SE, Ludwigshafen, Germany; isomers cis-9,trans-11 and trans-10,cis-12 each 10 g/d) or EFA+CLA. Milk composition was analyzed weekly, and blood samples were taken several times before and after parturition to determine plasma concentrations of metabolites related to lipid metabolism. Liver samples were obtained by biopsy on d 63 and 21 antepartum and on d 1, 28, and 63 postpartum to measure triglyceride concentration. Body composition was determined after slaughter. Supplementation of CLA reduced milk fat concentration, increased body fat mass, and improved energy balance (EB) in late and early lactation, but EB was lowest during late lactation in the EFA group. Cows with CLA treatment alone showed an elevated milk citrate concentration in early lactation, whereas EFA+CLA did not reveal higher milk citrate but did have increased acetone. Milk protein was increased in late lactation but was decreased in wk 1 postpartum in CLA and EFA+CLA. Milk urea was reduced by CLA treatment during the whole period. After calving, the increase of nonesterified fatty acids in plasma was less in CLA groups; liver triglycerides were raised lowest at d 28 in CLA groups. Our data confirm an improved metabolic status with CLA but not with exclusive EFA supplementation during early lactation. Increased milk citrate concentration in CLA cows points to reduced de novo FA synthesis in the mammary gland, but milk citrate was less affected in EFA+CLA cows, indicating that EFA supplementation may influence changes in mammary gland FA metabolism achieved by CLA.

Impact of post fermentation cooling patterns on fatty acid profile, lipid oxidation and antioxidant features of cow and buffalo milk set yoghurt

Background

In the manufacturing of set yoghurt, after reaching 4.6 pH, post fermentation cooling is applied to stop the bacterial activity. Depending upon the required textural and flavor attributes, one phase and two phase cooling patterns are accordingly selected. In one phase cooling, temperature of the yoghurt is rapidly decreased below 10 °C using blast freezing and then it is gradually dropped to 4-5 °C. In two phase cooling, temperature of yogurt is rapidly decreased to less than 20 °C and then it is gradually decreased to 4-5 °C. These cooling phases have a significant impact on textural and flavor perspectives of yoghurt. It is necessary to study the impact of industrially adopted cooling patterns on fatty acid profile, antioxidant characteristics, lipid oxidation and sensory characteristics of cow and buffalo milk set yoghurt.

Methods

This experiment was organized in a completely randomized design and every treatment was replicated five times to minimize the variation. Whole cow and buffalo milk without any standardization were converted to set yoghurt (400 g cups) using Strepotococcus thermophillus and Lactobacillus bulgaricus as starter bacteria. After reaching 4.6 pH, cow and buffalo yoghurt samples were exposed to three different cooling patterns. In first trial, samples of cow and buffalo yoghurt were cooled from 43 °C to 25 °C in 1 h and finally cooled to 4-5 °C in another hr. (T₁). In second trial, samples were cooled from 43 °C to 18 °C in 1 hr. and finally cooled down to 4-5 °C in another 1 h. (T₂). In third trial, samples were cooled from 43 °C to 4-5 °C in 2 h (T₁). Alteration in fatty acid profile, total antioxidant capacity, reducing power, free fatty acids, peroxide value, conjugated dienes, vitamin A, E, color and flavor of cow and buffalo yoghurt samples were assessed for 20 days at the frequency of 10 days.

Results

All the three cooling patterns had a non-significant effect on compositional attributes of yoghurt. Buffalo milk yogurt had higher percentage of fat, protein and total solids than yoghurt prepared from cow milk (p < 0.05). At zero day, DPPH free radical scavenging activity of T₂ and T₃ was significantly higher than T₁. This may be due to the longer exposure of T₁ at relatively higher temperature than T₂ and T₃. Effect of storage period up to 10 days was non-significant in T₂ and T_3. Reducing power of cow and buffalo milk yoghurt was also significantly affected by the cooling patterns applied. Reducing power of T₂ and T₃ was considerably higher than T₁ (p < 0.05). At zero-day, total antioxidant capacity of cow and buffalo milk yoghurt in T₃ was 42.6 and 61.4%, respectively. At zero day, total antioxidant capacity of T₂ and T₃ was significantly higher than T₁. Effect of storage on total antioxidant capacity of T₂ and T₃ remained non-significant till 10 days of storage. At zero day, the impact of cooling patterns on fatty acid profile of T₁, T₂ and T₃ was non-significant, whereas, storage period had a marked impact on fatty acid profile. After 10 days, T₁ was considerably different in fatty acids from T₂ and T₃. After 10 days of storage of cow milk yoghurt in T₁, concentration of C_4:0, C_6:0, C_8:0, C_10:0, C_12:0, C_14:0, C_16:0, C_18:0, C_18:1 and C_18:2 decreased by 0.1, 0.11, 0.09, 0.07, 0.21, 0.38, 0.28, 0.27, 0.44 and 0.06%, respectively. Cow milk yoghurt in T₁ after 10 days of storage, concentration of C_4:0, C_6:0, C_8:0, C_10:0, C_12:0, C_14:0, C_16:0, C_18:0, C_18:1 and C_18:2 decreased by 0.07, 0.15, 0.04, 0.17, 0.20, 0.34, 0.27, 0.36 and 0.04%, respectively. After 10 days of storage in T₂ and T₃, loss of fatty acids was 1.2 and 3.61% from C_4:0 to C_10:0, respectively. Milk type had no effect on peroxide value of yoghurt. Cooling of cow and buffalo yoghurt from 43 °C to 25 °C had a pronounced effect on peroxide value. At zero day, peroxide values of cow and buffalo yoghurt in T₁ were 0.32 and 0.33 (MeqO₂/kg). At zero day, peroxide value of cow and buffalo yoghurt in T₂ were 0.24 and 0.26 (MeqO₂/kg). At zero day, peroxide value cow and buffalo yoghurt in T₃ were 0.23 and 0.25 (MeqO₂/kg). Cooling patterns i.e. from 43 °C to 25, 18 and 5 °C (T₁, T₂ and T₃) had a significant effect on the amount of vitamin A and E. Concentration of vitamin A and E in T₁ were significantly less than T₂ and T₃. Cooling patterns had a significant effect on texture, T₁ had a thick texture with higher viscosity as compared to T₂ and T₃. Thickness of yoghurt was in the order of T₁ > T₂ > T₃ with no difference in color and flavor score till 10 days of storage.

Conclusion

Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T₁ were optimum till 10 days of storage.

Effects of abomasal infusion of essential fatty acids and conjugated linoleic acid on performance and fatty acid, antioxidative, and inflammatory status in dairy cows

The objective of this study was to test the effects of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) supplementation on fatty acid (FA) composition, performance, and systemic and hepatic antioxidative and inflammatory responses in dairy cows. Four cows (126 ± 4 d in milk) were investigated in a 4 × 4 Latin square and were abomasally infused with 1 of the following for 6 wk: (1) coconut oil (control treatment, CTRL; 38.3 g/d; providing saturated FA), (2) linseed and safflower oil (EFA treatment; 39.1 and 1.6 g/d, respectively; providing mainly α-linolenic acid), (3) Lutalin (BASF, Ludwigshafen, Germany; CLA treatment; cis-9,trans-11 and trans-10,cis-12 CLA, 4.6 g/d each), (4) or EFA+CLA. The initial dosage was doubled every 2 wk, resulting in 3 dosages (dosage 1, 2, and 3). Cows were fed a corn silage-based total mixed ration with a high n-6/n-3 FA ratio. Dry matter intake and milk yield were recorded daily, and milk composition was measured weekly. The FA compositions of milk fat and blood plasma were analyzed at wk 0, 2, 4, and 6. The plasma concentration and hepatic mRNA abundance of parameters linked to the antioxidative and inflammatory response were analyzed at wk 0 and 6 of each treatment period. Infused FA increased in blood plasma and milk of the respective treatment groups in a dose-dependent manner. The n-6/n-3 FA ratio in milk fat was higher in CTRL and CLA than in EFA and EFA+CLA. The sum of FA <C16 in milk fat decreased in CLA and EFA+CLA in a dosage-dependent manner. Energy-corrected milk and milk fat decreased in CLA and EFA+CLA in a dosage-dependent manner and were higher in EFA and CTRL than in CLA at dosages 2 and 3. Energy balance tended to be highest in CLA cows. Milk protein content was lower in CLA and EFA+CLA than in CTRL. Milk urea concentration decreased in CLA and EFA+CLA in a dosage-dependent manner and was lower in CLA and EFA+CLA than in EFA and CTRL at dosages 2 and 3. Milk citrate concentration increased in CLA in a dosage-dependent manner and was higher in CLA and EFA+CLA than in EFA and CTRL. Glutathione peroxidase activity in blood plasma was lower in CTRL than in EFA, and plasma concentration of β-carotene increased in EFA and EFA+CLA with dosage. Increased milk citrate pointed at reduced de novo FA synthesis and a better antioxidative status in milk due to CLA treatment. Supplementation with CLA may also affect milk protein synthesis, but EFA and CLA treatment did not influence the inflammatory status in a consistent manner in mid-lactating cows.

Enhancing Omega-3 Long-Chain Polyunsaturated Fatty Acid Content of Dairy-Derived Foods for Human Consumption

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are termed essential fatty acids because they cannot be synthesized de novo by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. n-3 PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C20) n-3 PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of n-3 PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of n-3 PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of n-3 PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance n-3 PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of n-3 LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual n-3 LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of n-3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.

Effect of Dietary Fish Oil on Mammary Gland Development and Milk Production of Holstein Cow

The aim of this study was to evaluate the effect of feeding oil supplement on mammary gland development and milk production responses in Holstein cows. Ten multiparous Holstein cows (42.2±9.2 d before calving, 3.25±0.25 body condition score, and 620±35 kg body weight) were randomly assigned to treatments. Treatments were a diet with oil added as palm oil (PO; n=5), or fish oil (FO; n=5) given to cows until 63 d in milk. Milk yield was recorded daily, milk composition (fat, protein, lactose, total solid and somatic cell count) was measured weekly and fatty acid profiles of milk fat were determined at first and last week of the experiment. Samples of mammary tissue were obtained at 7 and 63 d in milk by biopsy gun. Tissue slides were analyzed by Image J software. Results showed that fish oil supplemented diet compared to the palm oil supplemented diet increased milk production after 6 weeks of lactation (P<0.05), content of polyunsaturated fatty acids milk fat (P<0.05) and docosahexaenoic acid (P<0.01). Moreover, n-6:n-3 ratio was decreased by fish oil supplement (P<0.05). Histological studies showed that FO increased the relative percentage of tissue area occupied by epithelial cells as well as a number of total alveoli in each microscopic field (P<0.05). Data suggested that feeding fish oil during the dry period and early lactation could improve development and function of the mammary gland in the dairy cow.

Enhancement of dairy sheep cheese eating quality with increased n-3 long-chain polyunsaturated fatty acids

This study investigated the effect of different plant oil-infused and rumen-protected wheat-based pellets containing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on n-3 long-chain (≥C₂₀) polyunsaturated fatty acid (LC-PUFA) content, fatty acid recovery, and sensory attributes of ripened cheese from dairy sheep. During a 10-wk supplementary feeding trial, 60 dairy ewes balanced by live weight, milk yield, parity, and sire breed were randomly divided into 6 groups that were (1) supplemented with on-farm existing commercial wheat-based pellets without oil inclusion (control) or supplemented with wheat-based pellets infused with 50 mL/kg dry matter of oils from (2) canola, (3) rice bran, (4) flaxseed, (5) safflower, and (6) rumen-protected EPA + DHA. Milk samples from each treatment were collected separately by sire breed during the experimental period for cheese processing at the end of the experiment. Twelve batches of cheese (2 batches per treatment) were processed and ripened for 120 d. Three cheese samples were collected and analyzed for each cheese making session (total of 36 cheese samples) at d 120 of ripening. Processed cheese of rumen-protected EPA + DHA had the most efficiency at elevating total n-3 LC-PUFA [total EPA + DHA + docosapentaenoic acid (DPA, 22:5n-3] content compared with the control (0.49 vs. 0.28%). Flaxseed elicited the greatest enhancement of α-linolenic acid (ALA, 18:3n-3), whereas safflower was the most effective diet in enhancing the level of linoleic acid (18:2n-6) in cheese (1.29 vs. 0.71% and 4.8 vs. 3.3%, respectively). Parallel recoveries of n-3 and n-6 LC-PUFA were observed across all treatments except for α-linolenic acid and EPA. Cheese eating sensory traits were also highly affected by oil supplementation, with the highest score of 7.5 in cheese from the rice bran and flaxseed treatments. These results provide new insights into the biological mechanisms and processes that determine dairy ewe milk productivity by underpinning the vital biological role of n-3 LC-PUFA in not only enhancing the healthy composition of cheese from ewes but also translating it into consumer acceptability.

Effects of low dietary cation-anion difference induced by ruminal ammonium chloride infusion on performance, serum, and urine metabolites of lactating dairy cows

Objective

The objective of the present study was to determine ammonium chloride tolerance of lactating dairy cows, by examining effects of negative dietary cation anion difference (DCAD) induced by ruminal ammonium chloride infusion on performance, serum and urine minerals, serum metabolites and enzymes of lactating dairy cows.

Methods

Four primiparous lactating Chinese Holstein cows fitted with ruminal cannulas were infused with increasing amounts (0, 150, 300, or 450 g/d) of ammonium chloride in a crossover design. The DCAD of the base diet was 279 mEq/kg dry matter (DM) using the DCAD formula (Na + K – Cl – S)/kg of DM. Ammonium chloride infusion added the equivalent of 0, 128, 330, and 536 mEq/kg DM of Cl in treatments. According to the different dry matter intakes (DMI), the resulting actual DCAD of the four treatments was 279, 151, −51, and −257 mEq/kg DM, respectively.

Results

DMI decreased linearly as DCAD decreased. Yields of milk, 4% fat-corrected milk, energy-corrected milk, milk fat, and milk protein decreased linearly as DCAD decreased. Concentrations of milk protein and milk urea nitrogen increased linearly with decreasing DCAD. Concentration of Cl− in serum increased linearly and concentration of PO43- in serum increased quadratically as DCAD decreased. Urine pH decreased linearly and calculated urine volume increased linearly with decreasing DCAD. Linear increases in daily urinary excretion of Cl⁻, Ca²⁺, PO₄³⁻, urea N, and ammonium were observed as DCAD decreased. Activities of alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transferase in serum and urea N concentration in serum increased linearly as DCAD decreased.

Conclusion

In conclusion, negative DCAD induced by ruminal ammonium chloride infusion resulted in a metabolic acidosis, had a negative influence on performance, and increased serum enzymes indicating potential liver and kidney damage in lactating dairy cows. Daily ammonium chloride intake by lactating dairy cows should not exceed 300 g, and 150 g/d per cow may be better.

Combined effects of oleic, linoleic and linolenic acids on lactation performance and the milk fatty acid profile in lactating dairy cows

The potential combined effects of oleic, linoleic and linolenic acids supplementation on lactation performance and the milk fatty acid (FA) profile in dairy cows have not been well investigated. Our objective was to examine the effects of supplementation with a combination of these FA as well as the effects of removing each from the combination on lactation performance and the milk FA profile in dairy cows. Eight Holstein cows (101±11 days in milk) received four intravenously infused treatments in a 4×4 Latin square design, and each period lasted for 12 days which consisted of 5 days of infusion and 7 days of recovery. The control treatment (CTL) contained 58.30, 58.17 and 39.96 g/day of C18 : 1 cis-9; C18 : 2 cis-9, cis-12; and C18 : 3 cis-9, cis-12, cis-15, respectively. The other three treatments were designated --C18 : 1 (20.68, 61.17 and 41.72 g/day of C18 : 1 cis-9; C18 : 2 cis-9, cis-12; and C18 : 3 cis-9, cis-12, cis-15, respectively), -C18 : 2 (61.49, 19.55 and 42.13 g/day of C18 : 1 cis-9; C18 : 2 cis-9, cis-12; and C18 : 3 cis-9, cis-12, cis-15, respectively) and -C18 : 3 (60.89, 60.16 and 1.53 g/day of C18 : 1 cis-9; C18 : 2 cis-9, cis-12; and C18 : 3 cis-9, cis-12, cis-15, respectively). Dry matter intake and lactose content were not affected by the treatments, but the milk protein content was lower in cows treated with -C18 : 2 than that in CTL-treated cows. Milk yield as well as milk fat, protein and lactose yields were higher in cows treated with -C18 : 3 than the yields in CTL-treated cows, and these yields increased linearly as the unsaturation degree of the supplemental FA decreased. Compared with the CTL treatment, the -C18 : 2 treatment decreased milk C18 : 2 cis-9 content (by 2.80%) and yield (by 22.12 g/day), and the -C18 : 3 treatment decreased milk C18 : 3 cis-9, cis-12, cis-15 content (by 2.72%) and yield (by 22.33 g/day). In contrast, removing C18 : 1 cis-9 did not affect the milk content or yield of C18 : 1 cis-9. The -C18 : 2-treated cows had a higher C18 : 1 cis-9 content and tended to have a higher C18 : 1 cis-9 yield than CTL-treated cows. The yields of C8 : 0, C14 : 0 and C16 : 0 as well as <C16 : 0 tended to increase linearly as the unsaturation degree of the supplemental FA decreased (P=0.06, 0.07, 0.07 and 0.09, respectively). These results indicated that supplementation with C18 unsaturated FA might not independently affect the lactation performance and the milk FA profile of dairy cows.

Milk fatty acids profiles and milk production from dairy cows fed different forage quality diets

Thirty lactating Holstein cows were used to investigate the effects of different forages quality on milk fatty acids (FA) profiles and production. The cows were assigned to 3 dietary treatments (n = 10 per treatment) in a randomized block design with 3 repeated measures. They were fed the experimental diets for 90 d with 3 days of collection of samples for analysis at about 27 d intervals (samples were collected on days 28, 29, 30, 58, 59, 60, 88, 89 and 90). The treatments were (DM basis): 1) mixed forages diet (MF) consisting of 3.7% Chinese wild rye, 26.7% corn silage and 23.4% alfalfa hay; 2) corn stalk diet 1 (CS1) where corn stalk was used to formulate a similar chemical nutrient level to MF; 3) corn stalk diet 2 (CS2) which used corn stalk to formulate a similar forage level to MF for the diet. Dry matter intake and BW were similar between treatments, but daily milk yield, milk fat and protein yield decreased (P < 0.05) in CS1 and CS2 compared with MF, with CS2 being the lowest (P < 0.05). In total FA of milk, the compositions of C18:1c9, C18:3 and unsaturated FA increased (P < 0.05) in CS1 and CS2 compared with MF, and C18:0 and trans-C18:1 were trended to increase (P < 0.10), but C4:0-C16:0 were decreased (P < 0.05). Compared with cows fed CS2, cows receiving CS1 increased the compositions of C4:0 to C12:0 and C18:2 (P < 0.05). The results suggests feeding corn stalk could produce a greater proportion of unsaturated fatty acid (UFA) in milk fat without resulting in milk fat depression (MFD) in mid lactation cows, but simply increasing the ratio of concentrate in low forages diets is not an effective way to increase milk fat synthesis and milk production.

Effects of oils rich in linoleic and α-linolenic acids on fatty acid profile and gene expression in goat meat

Alteration of the lipid content and fatty acid (FA) composition of foods can result in a healthier product. The aim of this study was to determine the effect of flaxseed oil or sunflower oil in the goat diet on fatty acid composition of muscle and expression of lipogenic genes in the semitendinosus (ST) muscle. Twenty-one entire male Boer kid goats were fed diets containing different levels of linoleic acid (LA) and α-linolenic acid (LNA) for 100 days. Inclusion of flaxseed oil increased (p < 0.05) the α-linolenic acid (C18:3n-3) concentration in the ST muscle. The diet high in α-linolenic acid (p < 0.05) decreased the arachidonic acid (C20:4n-6) and conjugated linolenic acid (CLA) c-9 t-11 content in the ST muscle. There was a significant (p < 0.05) upregulation of PPARα and PPARγ gene expression and downregulation of stearoyl-CoA desaturase (SCD) gene in the ST muscle for the high α-linolenic acid group compared with the low α-linolenic acid group. The results of the present study show that flaxseed oil as a source of α-linolenic acid can be incorporated into the diets of goats to enrich goat meat with n-3 fatty acids, upregulate the PPARα and PPARγ, and downregulate the SCD gene expression.

Recent developments in lipid metabolism in ruminants – the role of fat in maintaining animal health and performance

Optimising farm animal performance has long been the key focus of worldwide livestock production research. Advances in the understanding of metabolism/phenotype associations have outlined the central role of the lipid metabolism of farm animals for economically relevant phenotypic traits, such as animal health (immune status, fertility/reproductive capacity, adaptability/metabolic flexibility, robustness, well being) and performance aspects (meat/milk quality and quantity) and have led to an extensive exploitation of lipid metabolism manipulation strategies (e.g. tailored nutritional regimes, alimentary/intravenous fat supplementation, rumen-protected fat feeding, hormone application). This contribution gives an overview of established concepts to tailor animals’ lipid metabolism and highlights novel strategies to expand these application-oriented approaches via improved analysis tools, omics-approaches, cell model systems and systems biology methods.

mRNA Expression of lipogenic enzymes in mammary tissue and fatty acid profile in milk of dairy cows fed flax hulls and infused with flax oil in the abomasum

In the present study, the effect of flax hulls with or without flax oil bypassing the rumen on the expression of lipogenic genes in the mammary tissue of dairy cows was investigated. A total of eight dairy cows were used in a replicated 4 × 4 Latin square design. There were four periods of 21 d each and four treatments: control diet with no flax hulls (CONT); diet with 9·88 % flax hulls in the DM (HULL); control diet with 500 g flax oil/d infused in the abomasum (COFO); diet with 9·88 % flax hulls in the DM and 500 g flax oil/d infused in the abomasum (HUFO). A higher mRNA abundance of sterol regulatory element binding transcription factor, fatty acid (FA) synthase, lipoprotein lipase (LPL), PPARγ1, stearoyl-CoA desaturase (SCD) and acetyl-coenzyme A carboxylase-α was observed in cows fed HULL than in those fed CONT, and HUFO had the opposite effect. Compared with CONT, COFO and HUFO lowered the mRNA abundance of SCD, which may explain the lower proportions of MUFA in milk fat with flax oil infusion. The mRNA abundance of LPL in mammary tissue and proportions of long-chain FA in milk fat were higher in cows fed COFO than in those fed CONT. The highest proportions of trans FA were observed when cows were fed HULL. The present study demonstrates that flax hulls with or without flax oil infusion in the abomasum can affect the expression of lipogenic genes in the mammary tissue of dairy cows, which may contribute to the improvement of milk FA profile.

Short communication: Feeding linseed oil to dairy goats with competent reticular groove reflex greatly increases n-3 fatty acids in milk fat

A crossover experiment was designed to compare the effects of 2 ways of feeding linseed oil on milk fat fatty acid (FA) composition. Ten lactating goats, trained to keep competent their inborn reticular groove reflex, received a daily dose of linseed oil (38 g/d) either with their solid (concentrate) feed (CON) or emulsified in skim milk and bottle-fed (BOT). Two groups of 5 goats received alternative and successively each of the treatments in two 15-d periods. α-Linolenic acid in milk fat rose up to 13.7% in the BOT versus 1.34% in the CON treatment. The n-6 to n-3 FA ratio was significantly reduced in goats receiving bottle-fed linseed oil (1.49 vs. 0.49). Contents of rumen biohydrogenation intermediates of dietary unsaturated FA were high in milk fat of goats under the CON treatment but low in those in the BOT treatment. These results point to a clear rumen bypass of the bottle-fed linseed oil. This strategy allows obtaining milk fat naturally very rich in n-3 FA and very low in trans FA. Translating this approach into practical farm conditions could enable farmers to produce milk enriched in specific FA.

Impact of region on the composition of milk fatty acids in China

BACKGROUND

Milk composition and its fatty acid profile have received much attention with respect to improving human health. However, limited work has been conducted to assess the composition of milk fat in China, which is the third largest producer of milk in the world. In this study the effects of geographical region and seasonal changes (spring and summer) on the fatty acid composition of milk samples collected from six Chinese farms were investigated.

RESULTS

Milk fat and protein contents, as well as some individual fatty acids and five fatty acid groups, were found to be unaffected by season, but they did show significant differences by geographical region. Levels of milk cis-9, trans-11 conjugated linoleic acid decreased in summer and increased in spring, increased in north (Hohhot), northeast (Harbin), north centre (Beijing) and northwest (Xi'an) China and decreased in far northwest (Urumqi) and east (Chuzhou) China. Monounsaturated fatty acids increased in east and northwest China and decreased in northeast China, while polyunsaturated fatty acids increased in far northwest and north centre China and decreased in northeast China.

CONCLUSION

This study provides relevent information that contributes to the understanding of parameters affecting variability of milk fatty acid profiles.

Supplementation of increasing amounts of linseed oil to dairy cows fed total mixed rations: effects on digestion, ruminal fermentation characteristics, protozoal populations, and milk fatty acid composition

The effect of linseed oil (LO) supplementation on nutrient digestibility, forage (i.e., timothy hay) in sacco ruminal degradation, ruminal fermentation characteristics, protozoal populations, milk production, and milk fatty acid (FA) profile in dairy cows was investigated. Four ruminally cannulated, primiparous lactating cows were used in a 4 × 4 Latin square design (28-d periods). They were fed a total mixed ration (50:50 forage:concentrate (F:C) ratio [dry matter (DM) basis] without supplementation (control, CTL), or supplemented (wt/wt; DM basis) with LO at 2, 3, or 4%. Supplementation with LO had no effect on DM intake (19 kg/d) and apparent total-tract digestibility of nutrients (organic matter, neutral detergent fiber, acid detergent fiber, starch, and gross energy). Ruminal pH, ammonia, and total volatile FA concentrations were not changed by LO supplementation to diets. Extent of changes in volatile FA pattern and effective ruminal degradability of DM of timothy hay were minor. Neither the total numbers nor the genera distribution of protozoa was changed by the addition of increasing amounts of LO to the diet. Milk yield increased linearly (26.1, 27.3, 27.4, and 28.4 kg/d for CTL to LO4, respectively) as the amount of LO added to the diet increased. Milk fat content was not affected by LO supplementation, whereas milk protein content decreased linearly with increasing amounts of LO in the diet. Milk fat proportions of several intermediates of ruminal biohydrogenation of polyunsaturated FA (i.e., trans-10 18:1, trans-11 18:1, cis-9,trans-11 18:2, trans-11,cis-15 18:2, and cis-9,trans-11,cis-15 18:3) increased linearly with LO addition to the diet. The proportion of cis-9,cis-12 18:2 decreased linearly (2.06, 1.99, 1.91, and 1.83% for CTL to LO4, respectively) as the amount of LO in the diet increased. Milk fat content of cis-9,cis-12,cis-15 18:3 increased as the level of LO in the diet increased up to 3% but no further increase was observed when 4% of LO was fed (0.33, 0.79, 0.86, and 0.86% for CTL to LO4, respectively). A similar quadratic response to LO supplementation was also observed for cis-5,cis-8,cis-11,cis-14,cis-17 20:5 and cis-5,cis-7,cis-10,cis-13,cis-16 22:5. The results of the present study show that LO can be safely supplemented up to 4% in forage-based diets of dairy cows to enrich milk with potential health beneficial FA (i.e., n-3 FA) without causing any detrimental effects on rumen function, digestion, and milk production.

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.

Effects of duodenal infusion of free α-linolenic acid on the plasma and milk proteome of lactating dairy cows

This study is an exploratory analysis for understanding the effect of a duodenal infusion of an α-linolenic acid (LNA) on the plasma and milk proteome of lactating dairy cows. Four primiparous Holstein cows were fitted with duodenal cannulas and received 0, 100, 200, 300 and 400 g/day of LNA in a two-treatment crossover design. Blood and milk were collected for determination of protein composition by two-dimensional gel electrophoresis. Alteration of protein spots was detected and identified using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS). Plasma haptoglobin levels, and milk β-casein A2, αs1-casein variant and albumin, did not differ in cows after infusion of 0, 100, 200 and 300 g/day of LNA, but were increased after the cows received duodenal infusion of 400 g/day of LNA. Western blot analysis of haptoglobin expression in plasma confirmed the alterations in protein expression seen using MS. This study demonstrated that infusion of high doses of LNA by duodenal cannula can result in metabolic stress within the bovine intestine and in changes in milk composition.

Short Communication: Effects of duodenal infusion of increasing amounts of α-linolenic acid on composition and susceptibility to peroxidation of blood lipids in lactating dairy cows

Sun, P., Wang, J.-Q., Liu, Q.-S., Khas-Erdene and Yang, G. 2012. Short Communication: Effects of duodenal infusion of increasing amounts of α-linolenic acid on composition and susceptibility to peroxidation of blood lipids in lactating dairy cows. Can. J. Anim. Sci. 92: 219–223. Duodenal infusion of increasing amounts of α-linolenic acid (LNA) in dairy cows linearly decreased the percentages of 18:0, 18:2n-6 and saturated fatty acids (P<0.01), linearly and quadratically reduced 23:0 and 18:1 cis-9 (P<0.01), but linearly increased the content of 18:3 n-3 and PUFA (P<0.01) in blood plasma. As amount infused increased, concentrations of high-density lipoprotein cholesterol and total cholesterol increased quadratically and peaked at 139.9 mg dL−1 and 182.0 mg dL−1, respectively (P<0.01). No differences were observed in the activity of blood serum total superoxide dismutase and total antioxidant capacity, but the thiobarbituric acid reactive substances tended (P=0.07) to increase linearly. Duodenally infused increasing amounts of LNA altered the composition of fatty acids and distribution of lipids in blood, but did not affect the oxidative stability of the blood in dairy cows.

Digestion, milk production and milk fatty acid profile of dairy cows fed flax hulls and infused with flax oil in the abomasum

Flax hull, a co-product obtained from flax processing, is a rich source of n-3 fatty acids (FA) but there is little information on digestion of flax hull based diets and nutritive value of flax hull for dairy production. Flax oil is rich in α-linolenic acid (LNA) and rumen bypass of flax oil contributes to increase n-3 FA proportions in milk. Therefore, the main objective of the experiment was to determine the effects of abomasal infusion of increasing amounts of flax oil on apparent digestibility, dry matter (DM) intake, milk production, milk composition, and milk FA profile with emphasis on the proportion of LNA when cows were supplemented or not with another source of LNA such as flax hull. Six multiparous Holstein cows averaging 650±36 kg body weight and 95±20 d in milk were assigned to a 6×6 Latin square design (21-d experimental periods) with a 2×3 factorial arrangement of treatments. Treatments were: 1) control, neither flax hull nor flax oil (CON), 2) diet containing (DM basis) 15·9% flaxseed hull (FHU); 3) CON with abomasal infusion of 250 g/d flax oil; 4) CON with abomasal infusion of 500 g/d flax oil; 5) FHU with abomasal infusion of 250 g/d flax oil; 6) FHU with abomasal infusion of 500 g/d flax oil. Infusion of flax oil in the abomasum resulted in a more pronounce decrease in DM intake for cows fed the CON diets than for those fed the FHU diets. Abomasal infusion of flax oil had little effect on digestibility and FHU supplementation increased digestibility of DM and crude protein. Milk yield was not changed by abomasal infusion of flax oil where it was decreased with FHU supplementation. Cows fed FHU had higher proportions of 18:0, cis9-18:1, trans dienes, trans monoenes and total trans in milk fat than those fed CON. Proportion of LNA was similar in milk fat of cows infused with 250 and 500 g/d flax oil in the abomasum. Independently of the basal diet, abomasal infusion of flax oil resulted in the lowest n-6:n-3 FA ratio in milk fat, suggesting that the most important factor for modification of milk FA profile was the amount of n-3 FA bypassing the rumen and not the amount of flax hull fed to dairy cows. Moreover, these data suggest that there is no advantage to supply more than 250 g/d of flax oil in the abomasum to increase the proportion of LNA in milk fat.

Effects of different doses of free alpha-linolenic acid infused to the duodenum on the immune function of lactating dairy cows

This study investigated the effect of a duodenal infusion of a C18:3 free fatty acid on the immune function of lactating dairy cows. Four primiparous Chinese Holstein cows fitted with duodenal cannulas received 0, 100, 200, 300, and 400 g/d of alpha-linolenic acid (LNA) in a two-treatment crossover design. Blood was collected and serum IgA, IgG, IgM, prostaglandin E2 (PGE2) and Th1/Th2 cytokines were determined. Results showed that increasing the supply of LNA to the small intestine of dairy cows linearly increased serum IgG and quadratically enhanced interferon-gamma (p < 0.05), whereas the concentrations of PGE2 declined linearly (p < 0.05) and those of interleukin (IL)-4 tended to decrease (p = 0.08). No difference was observed in serum IgA, IgM or other cytokines, such as IL-2, IL-6 and IL-10. This study demonstrated that in dairy cows, a post-ruminal infusion of high doses of LNA has immunomodulatory effects, possibly associated with a predisposition to a Th1-type response.