Supplemental algal meal alters the ruminal trans-18:1 fatty acid and conjugated linoleic acid composition in cattle

Changes in Chemical Composition and Fatty Acid Profile of Milk and Cheese and Sensory Profile of Milk via Supplementation of Goats' Diet with Marine Algae

The aim of the present study was to assess the effects of the low level of Schizochytrium limacinum marine algae (daily 5 g per animal) on the milk, cheese, and whey composition; fatty acid profile of milk and cheese; and the sensory profile of goat milk using an e-nose device. Thirty Alpine goats were randomly divided into two groups: the control group (C, n = 15)-fed grass with daily 600 g concentrate and the experimental group (MA, n = 15) who received the same forage and concentrate supplemented with 5 g/head/day marine algae. Animals were kept indoors and the investigation period lasted 52 days, including the first six weeks as the period of adaptation and the last 10 days as the treatment period. During the adaptation period, bulk milk samples from each group were collected once a week (0, 7, 14, 21, 28, 35, and 42 d), while during the treatment period (10 days), bulk milk samples from each group were taken every day, and cheese samples were processed from bulk milk each day from both groups. Marine algae supplementation had no negative effect on milk composition. In contrast, the marine algae inclusion significantly elevated the fat and protein content of whey and the protein content of cheese, as well as the recovery of fat and protein in the curd, while increasing the cheeses' moisture content on a fat-free basis. The marine algae supplementation significantly increased the docosahexaenoic acid (DHA) and the rumenic acid (CLA c9t11) concentrations and decreased the n-6/n-3 ratio in the milk and cheese. There were no significant differences between the C and the MA group with regard to the sensory profiles of the milk. It can be concluded that the milk obtained from goats given daily supplementation of 5g of MA has a fatty acid profile more beneficial to human health, without any negative effects on the milk's aromatic components.

Algae as Feedstuff for Ruminants: A Focus on Single-Cell Species, Opportunistic Use of Algal By-Products and On-Site Production

There is a wide range of algae species originating from a variety of freshwater and saltwater habitats. These organisms form nutritional organic products via photosynthesis from simple inorganic substances such as carbon dioxide. Ruminants can utilize the non-protein nitrogen (N) and the cell walls in algae, along with other constituents such as minerals and vitamins. Over recent decades, awareness around climate change has generated new interest into the potential of algae to suppress enteric methane emissions when consumed by ruminants and their potential to sequester atmospheric carbon dioxide. Despite the clear potential benefits, large-scale algae-livestock feedstuff value chains have not been established due to the high cost of production, processing and transport logistics, shelf-life and stability of bioactive compounds and inconsistent responses by animals under controlled experiments. It is unlikely that algal species will become viable ingredients in extensive grazing systems unless the cost of production and practical systems for the processing, transport and feeding are developed. The algae for use in ruminant nutrition may not necessarily require the same rigorous control during the production and processing as would for human consumption and they could be grown in remote areas or in marine environments, minimizing competition with cropping, whilst still generating high value biomass and capturing important amounts of atmospheric carbon. This review will focus on single-cell algal species and the opportunistic use of algal by-products and on-site production.

Enrichment of Ewe’s Milk with Dietary n-3 Fatty Acids from Palm, Linseed and Algae Oils in Isoenergetic Rations

Increasing the levels of n-3 fatty acids (FA) in dairy products is an important goal in terms of enhancing the nutritional value of these foods for the consumer. The purpose of this research was to evaluate the effects of linseed and algae oil supplements in ovine isoenergetic diets on healthy milk fatty acid composition, mainly n-3. Seventy-two Churra dairy ewes were divided and randomly assigned to four experimental treatments for 6 weeks. The treatments consisted of a TMR (40:60 forage:concentrate ratio) that varied according to the inclusion of different types of fat (23 g/100 g TMR): hydrogenated palm oil (control), linseed oil (LO), calcium soap of linseed oil (CaS-LO) and marine algae oil (AO). The most effective lipid supplement to increase n-3 FA in milk was AO. 22:6 n-3 and total n-3 PUFA content increased from 0.02 and 0.60% (control) to 2.63 and 3.53% (AO), respectively. All diets supplemented with n-3 FA diminished the content of saturated FA in milk and its atherogenic index, while the levels of trans-11 18:1 and cis-9 trans-11 18:2 significantly increased. Overall, the enhancement of n-3 FA in ewe’s milk would be advantageous for the manufacture of nutritionally improved cheeses.

Freeze-dried Nannochloropsis oceanica biomass protects eicosapentaenoic acid (EPA) from metabolization in the rumen of lambs

Eicosapentaenoic acid (EPA) from freeze-dried biomass of Nannochloropsis oceanica microalgae resists ruminal biohydrogenation in vitro, but in vivo demonstration is needed. Therefore, the present study was designed to test the rumen protective effects of N. oceanica in lambs. Twenty-eight lambs were assigned to one of four diets: Control (C); and C diets supplemented with: 1.2% Nannochloropsis sp. oil (O); 12.3% spray-dried N. oceanica (SD); or 9.2% N. oceanica (FD), to achieve 3 g EPA /kg dry matter. Lambs were slaughtered after 3 weeks and digestive contents and ruminal wall samples were collected. EPA concentration in the rumen of lambs fed FD was about 50% higher than lambs fed SD or O diets. Nevertheless, the high levels of EPA in cecum and faeces of animals fed N. oceanica biomass, independently of the drying method, suggests that EPA was not completely released and absorbed in the small intestine. Furthermore, supplementation with EPA sources also affected the ruminal biohydrogenation of C18 fatty acids, mitigating the shift from the t10 biohydrogenation pathways to the t11 pathways compared to the Control diet. Overall, our results demonstrate that FD N. oceanica biomass is a natural rumen-protected source of EPA to ruminants.

Effect of Marine Algae Supplementation on Somatic Cell Count, Prevalence of Udder Pathogens, and Fatty Acid Profile of Dairy Goats' Milk

The aim of this study was to evaluate the effect of the Schizochytrium limacinum marine algae on the milk composition and fatty acid profile, somatic cell count, and prevalence of pathogen bacteria in the raw milk of multiparous Alpine goats. Twenty-eight dairy goats were randomly allocated to two groups: control group (C)-fed with 1500 g alfalfa hay and 600 g concentrate; experimental group (MA)-received the same forages and concentrate supplemented with 10 g/head/day marine algae. The goats were housed indoors, while the experiment lasted five weeks, and the milk samples were taken every week. Marine algae feeding had no negative effect on milk composition. The marine algae inclusion significantly decreased the milk somatic cell count and the presence of udder pathogens in the MA group. Mean somatic cell count and presence of udder pathogens were 5.73 log cells/mL and 31%, respectively, in the C group, while these values were 5.34 log cells/mL and 10%, respectively, in the MA group. The marine algae supplementation significantly increased DHA and rumenic acid concentration in the milk of the MA group (0.32 and 0.99 g/100 g of fatty acids, respectively) compared to the C group (0.04 and 0.65 g/100 g of fatty acids, respectively). It can be concluded that a diet supplemented with marine algae significantly improves the udder health of goats and the concentrations of health-promoting fatty acids in milk.

Effects of replacing starch with three sugars in a concentrate and forage diet on in vitro rumen fermentation, fatty acid composition and related bacteria

Context Replacing starch with sugar could maintain dietary energy density with reduced risks of rumen acidosis and milk fat depression, but the underlying mechanism is not well understood, and the effects of sugar feeding might vary among sugars. Aims Objectives of the present study were to evaluate the effects of replacing corn starch in a diet containing 40:60 forage-to-concentrate ratio (control) with 3%, 6% and 9% of sucrose, fructose and lactose on in vitro rumen fermentation, fatty acid (FA) composition and populations of bacteria involved in the production of trans-11 and trans-10 FA. Methods A 3 × 3 + 1 (control) factorial experimental design was used, and the pH, concentrations of volatile fatty acids (VFA) and ammonia-N, profiles of FA and the relative abundance of four trans-11-producing bacteria and two trans-10 FA-producing bacteria were measured after a 6-h incubation. Key results Replacing dietary corn starch with sucrose, fructose and lactose neither altered the concentration of total VFA after 6-h fermentation, nor decreased the pH, except for substitution with 9% sucrose. Increased butyrate proportions and decreased branched-chain VFA proportions were the common effects in sugar treatments, but the proportions of acetate and propionate varied among sugars. Lactose inclusion in the diet led to a higher pH, greater acetate and butyrate concentrations, and lower propionate concentrations than did sucrose inclusion. Sugar substitution decreased the concentrations of C18:1 trans-4 and most C18:2 isomers, but did not influence the major isomers related to trans-11 and trans-10 biohydrogenation pathways. Abundance of the four measured trans-11 FA-producing bacteria was increased by sugars, with sucrose showing a greater influence than did fructose and lactose. As to trans-10 FA-producing bacteria, only Megasphaera elsdenii populations were decreased by 3% and 6% fructose inclusion compared with the control. Dose-effect varied among sugars and the parameters measured, with sucrose having the most obvious dose effect among the three sugars; however, fructose affected mainly fermentation parameters, while lactose affected mainly C18 FA profiles. Conclusions Replacing corn starch in a high-concentrate diet with up to 9% of sucrose, fructose and lactose differentially affected rumen fermentation and rumen FA metabolism, by influencing the abundance of rumen bacteria involved in rumen FA biohydrogenation. Implications Lactose may be more efficient in increasing milk fat than are sucrose and fructose, and dose effect should be considered in the utilisation of sucrose.

Conditions Associated with Marine Lipid-Induced Milk Fat Depression in Sheep Cause Shifts in the In Vitro Ruminal Metabolism of 1-13C Oleic Acid

Shifts in ruminal oleic acid (OA) metabolism have received little research attention but recent studies have suggested their association with marine lipid-induced milk fat depression (MFD) in ewes and cows. Measurement of specific products of OA within the complex mixture of digesta lipids is however challenging. Therefore, this in vitro trial combined the isotopic labelling technique with the use of rumen inoculum from cannulated sheep fed a diet supplemented or not with 2% of fish oil (which has been demonstrated to cause MFD in dairy ruminants) to characterize the metabolism of OA in response to ruminal alterations associated with MFD. The products of 13C-OA after 24 h of incubation were analysed by gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS). Numerous 13C-labeled 18:1 intermediates and oxygenated FA were detected and no elongation or desaturation of 13OA occurred. Diet supplementation with fish oil (i.e., MFD conditions) resulted in no unique metabolites of 13OA but in relevant changes in the relative contribution of specific metabolic pathways. The inhibition of 18:0 saturation caused by this treatment appeared largely attributable to increased oxygenated FA proportion, in particular the candidate milk fat inhibitor 10-oxo-18:0, and warrants further research on the association between MFD and oxygenated FA. Changes in the concentration of 13C-labeled trans 18:1 intermediates but not in cis 18:1, were also observed.

The effect of dietary supplementation with Aurantiochytrium limacinum on lactating dairy cows in terms of animal health, productivity and milk composition

The aim of this study was to investigate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA), on a variety of health and productivity parameters in lactating cows. Twenty-four cows were blocked by parity and number of days in milk and then randomly assigned to a control (CON; n = 12) group with no algal supplementation, or a treatment group (AURA; n = 12) provided with 100 g AURA cow^-1  day^-1 or 16 g DHA cow^-1  day^-1 . A variety of health and productivity measurements were taken, and results indicated that supplementation had no negative effects on animal health in terms of somatic cell count, haematological and biochemical blood parameters, while body condition was marginally improved by algal supplementation. No differences were found for the various production parameters measured; however, a tendency towards increased milk production was observed for the AURA group during the final stage of the study (+4.5 kg cow^-1  day^-1 , day 78-84). The fatty acid profile of milk was improved by supplementation, with significantly lower saturated fatty acids, significantly higher omega-3 fatty acids and an improved omega-3/omega-6 ratio observed when compared to the control group. The amount of DHA in the milk of cows provided 105 g AURA head^-1  day^-1 was 4.7 mg/100 g milk with a peak transfer efficiency from feed to milk at day 49 of 8.3%. These results indicate that supplementation with 105 g AURA head^-1  day^-1 resulted in the successful enrichment of milk with DHA without negatively impacting the health or productivity of the animals.

Enhancing the DHA content in milk from dairy cows by feeding ALL-G-RICH™

The objective of this study was to evaluate the effect of the dietary inclusion of 6 g/kg dry matter intake of an unextracted Aurantiochytrium limacinum algae (AURA) in mid-lactation Italian Friesian cows under commercial conditions on milk yield, milk composition and docosahexaenoic acid (DHA) content. Cows were allocated to two groups (n = 18; 108.2 ± 66.1 and 104.4 ± 54.6 days in milk, control and treated groups, respectively). Feeding AURA for 84 d had no effect on dry matter intake, body condition score or weight gain, but did improve milk yield by 1.9 kg/cow/d (+5.4%; P < 0.1) over the course of the experiment. Milk fat concentration declined by 12% (P < 0.0001) without any significant change in 4% fat corrected milk, protein or lactose. Supplementing AURA for 12 weeks substantially altered the fatty acid profile of milk compared with milk from CON-fed cows such that the proportion of unsaturated fatty acids increased, omega-3 fatty acid content increased by 73.1% (P < 0.0001) and was accompanied by a favourable increase in the omega-3:6 fatty acid ratio by 75.0% (P < 0.0001). The AURA supplement, during day 7–84, increased the DHA concentration to 0.37 g /100 g milk total fatty acids (P < 0.0001) with a mean transfer efficiency of 18.1% from feed to milk. Together these results indicated that supplementing a dairy cow diet with DHA-rich microalgae is a feasible and efficient means for creating DHA-enriched milk for human consumption.

In vitro response to EPA, DPA, and DHA: Comparison of effects on ruminal fermentation and biohydrogenation of 18-carbon fatty acids in cows and ewes

The modulation of milk fat nutritional quality through fish oil supplementation seems to be largely explained by the action of n-3 very long chain polyunsaturated fatty acids (PUFA) on ruminal biohydrogenation (BH) of C18 fatty acids (FA). However, relationships among this action, disappearance of those PUFA in the rumen, and potential detrimental consequences on ruminal fermentation remain uncertain. This study compared the effect of 20:5n-3 (eicosapentaenoic acid; EPA), 22:5n-3 (docosapentaenoic acid; DPA), and 22:6n-3 (docosahexaenoic acid; DHA) on rumen fermentation and BH of C18 FA and was conducted simultaneously in cows and sheep to provide novel insights into interspecies differences. The trial was performed in vitro using batch cultures of rumen microorganisms with inocula collected from cannulated cows and ewes. The PUFA were added at a dose of 2% incubated dry matter, and treatment effects on ruminal C18 FA concentrations, PUFA disappearances, and fermentation parameters (gas production, ammonia and volatile FA concentrations, and dry matter and neutral detergent fiber disappearances) were examined after 24 h of incubation. A principal component analysis suggested that responses to PUFA treatments explained most of the variability; those of ruminant species were of lower relevance. Overall, EPA and DHA were equally effective for inhibiting the saturation of trans-11 18:1 to 18:0 and had a similar influence on ruminal fermentation in cows and sheep (e.g., reductions in gas production and acetate:propionate ratio). Nevertheless, DHA further promoted alternative BH pathways that lead to trans-10 18:1 accumulation, and EPA seemed to have specific effects on 18:3n-3 metabolism. Only minor variations attributable to DPA were observed in the studied parameters, suggesting a low contribution of this FA to the action of marine lipids. Although most changes due to the added PUFA were comparable in bovine and ovine, there were also relevant specificities, such as a stronger inhibition of 18:0 formation in cows and a greater increase in 18:3n-3 metabolites in sheep. No direct relationship between in vitro disappearance of the incubated PUFA and effect on BH (in particular, inhibition of the last step) was found in either cows or ewes, calling into question a putative link between extent of disappearance and toxicity for microbiota. Conversely, an association between the influence of these PUFA on ruminal lipid metabolism and fermentation may exist in both species. In vivo verification of these findings would be advisable.

Dose and time response of ruminally infused algae on rumen fermentation characteristics, biohydrogenation and Butyrivibrio group bacteria in goats

BACKGROUND

Micro-algae could inhibit the complete rumen BH of dietary 18-carbon unsaturated fatty acid (UFAs). This study aimed to examine dose and time responses of algae supplementation on rumen fermentation, biohydrogenation and Butyrivibrio group bacteria in goats.

METHODS

Six goats were used in a repeated 3 × 3 Latin square design, and offered a fixed diet. Algae were infused through rumen cannule with 0 (Control), 6.1 (L-Alg), or 18.3 g (H-Alg) per day. Rumen contents were sampled on d 0, 3, 7, 14 and 20.

RESULTS

H-Alg reduced total volatile fatty acid concentration and acetate molar proportion (P < 0.05), and increased propionate molar proportion (P < 0.05), whereas L-Alg had no effect on rumen fermentation. Changes in proportions of acetate and propionate in H-Alg were obvious from d 7 onwards and reached the largest differences with the control on d 14. Algae induced a dose-dependent decrease in 18:0 and increased trans-18:1 in the ruminal content (P < 0.05). H-Alg increased the concentrations of t9, t11-18:2 and t11, c15-18:2 (P < 0.05). L-Alg only seemed to induce a transient change in 18-carbon isomers, while H-Alg induced a rapid elevation, already obvious on d 3, concentrations of these fatty acid rose in some cases again on d 20. Algae had no effect on the abundances of Butyrivibrio spp. and Butyrivibrio proteoclasticus (P > 0.10), while H-Alg reduced the total bacteria abundance (P < 0.05). However, this was induced by a significant difference between control and H-Alg on d 14 (-4.43 %). Afterwards, both treatments did not differ as increased variation in the H-Alg repetitions, with in some cases a return of the bacterial abundance to the basal level (d 0).

CONCLUSIONS

Changes in rumen fermentation and 18-carbon UFAs metabolism in response to algae were related to the supplementation level, but there was no evidence of shift in ruminal biohydrogenation pathways towards t10-18:1. L-Alg mainly induced a transient effect on rumen biohydrogenation of 18-carbon UFAs, while H-Alg showed an acute inhibition and these effects were not associated with the known hydrogenating bacteria.

Partially replacing cornstarch in a high-concentrate diet with sucrose inhibited the ruminal trans-10 biohydrogenation pathway in vitro by changing populations of specific bacteria

Background

The positive influence of replacing dietary starch with sugar on milk fat production has been proposed to be partially attributed to the inhibition of the rumen trans-10 biohydrogenation pathway. However, whether and how sucrose inhibits the rumen trans-10 biohydrogenation pathway remains elusive.

Results

A batch in vitro incubation system was used to evaluate effects of replacing cornstarch in a high-concentrate diet (forage to concentrate ratio = 40:60) with 0 (control), 3, 6 and 9 % of sucrose on rumen fermentation pattern, fatty acid (FA) biohydrogenation pathways and bacterial populations relating to trans-11 to trans-10 biohydrogenation pathways. Replacing dietary cornstarch with sucrose did not alter rumen pH or concentrations of total volatile fatty acids (VFA) in comparison with the control but significantly influenced the profiles of individual VFA. The molar proportions of butyrate and valerate were linearly increased, while that of acetate was quadratically decreased and those of propionate, isobutyrate and isovalerate were linearly decreased with increasing concentrations of sucrose in the diet. Furthermore, replacing cornstarch with sucrose led to a linear decrease in C18:1 trans-10, linear increases in the proportions of C18:1 trans-11, C18:2n-6 and the ratio of trans-11 to trans-10, and linear decreases in biohydrogenation of C18:2n-6 and C18:3n-3. The abundance of Butyrivibrio fibrisolvens, a butyrate and CLA cis-9, trans-11 producer, was increased with the increasing inclusion of sucrose in the diet, while the population of Megasphaera elsdenii, a CLA trans-10, cis-12 producer, was significantly decreased by all levels of sucrose replacements.

Conclusions

These results indicate that replacing starch in a high-concentrate diet with sucrose increased butyrate production and inhibited the rumen trans-10 biohydrogenation pathway, which was at least partially due to increased abundance of Butyrivibrio fibrisolvens and decreased abundance of Megasphaera elsdenii.

Effects of various dietary lipid additives on lamb performance, carcass characteristics, adipose tissue fatty acid composition, and wool characteristics

Tasco (Ascophyllum nodosum; TA) was compared to canola (CO), flax (FO), and safflower oils (SO) for effects on performance, carcass characteristics, and fatty acid profiles of adipose tissue in skirt muscle (SM), subcutaneous and perirenal adipose tissues, and wool production and quality characteristics of Canadian Arcott lambs. Fifty-six lambs were randomly assigned to dietary treatments (n = 14 per treatment). Diets consisted of a pelleted, barley-based finishing diet containing either TA, CO, FO, or SO (2% of dietary DM). Feed deliveries and orts were recorded daily. Lambs were weighed weekly and slaughtered once they reached ≥ 45 kg BW. Carcass characteristics, rumen pH, and liver weights were determined at slaughter. Wool yield was determined on mid-side patches of 100 cm2 shorn at d 0 and on the day before slaughter (d 105 or 140). Dye-bands were used to determine wool growth, micrometer and staple length. Adipose tissues and SM samples were taken at slaughter and analyzed for FA profiles. No effects were observed on intake, growth, or carcass characteristics. A greater (P = 0.02) staple strength of lambs fed CO was the only effect observed in wool. Flax oil increased total n-3 and decreased the n-6/n-3 ratio in tissue FA profiles (P < 0.001) in comparison to other diets. Tasco increased (P ≤ 0.001) SFA/PUFA in all tissues, whereas concentrations of CLA c-9, t-11 were greatest with SO in all tissues (P ≤ 0.02), compared to other diets. These results suggest Tasco supplementation did not improve the n-3/n-6 or SFA/PUFA ratios of lamb adipose tissues compared to other dietary lipid additives.

Spirulina (Spirulina platensis) algae supplementation increases microbial protein production and feed intake and decreases retention time of digesta in the rumen of cattle

Cattle consuming pastures low in protein have low liveweight gain due to low rumen degradable protein (RDP) supply and thus low microbial crude protein (MCP) production and efficiency of MCP production [EMCP, g MCP/kg digestible organic matter (DOM)]. Nitrogen supplements can increase MCP production and EMCP of cattle grazing low protein pastures. The objective of this study was to compare the effects of supplementation with a non-protein-N source (NPN), in this case urea and ammonium sulfate (US), with a single-cell algal protein source (Spirulina platensis), on intake, microbial protein supply and digestibility in cattle. Nine cannulated Bos indicus steers [initial liveweight 250.1 ± 10.86 (s.d.) kg] were fed Mitchell grass hay (Astrebla spp; 6.1 g N, 746 g NDF/kg DM) ad libitum and were supplied with increasing amounts of US (0, 6, 13, 19 and 33 g US DM/kg hay DM) or Spirulina 0, 0.5, 1.4, 2.5 and 6.1 g Spirulina DM/kg W.day in an incomplete Latin square design. The response of MCP production and EMCP to increasing amounts of the two supplements was different, with a greater response to Spirulina evident. The MCP production was predicted to peak at 140 and 568 g MCP/day (0.64 and 2.02 g MCP/kg W.day) for the US and Spirulina supplements, respectively. The highest measured EMCP were 92 and 166 g MCP/kg DOM for the US and Spirulina treatments at 170 and 290 g RDP/kg DOM, respectively, or a Spirulina intake of 5.7 g DM/kg W.day. Increasing RDP intake from US and Spirulina resulted in an increase in Mitchell grass hay intake and rumen NH3-N concentration and reduced the retention time of liquid and particulate markers and digesta DM, NDF and lignin in the rumen with greater changes due to Spirulina. Total DM intake peaked at a Spirulina supplement level of 4.6 g Spirulina DM/kg W.day with a 2.3-fold higher DOM intake than Control steers. Rumen NH3-N concentrations reached 128 and 264 mg NH3-N/L for the US and Spirulina treatments with a significant increase in the concentration of branched-chain fatty acids for the Spirulina treatment. The minimum retention time of liquid (Cr-EDTA; 23 and 13 h) and particulate (Yb; 34 and 22 h) markers in the rumen were significantly lower for Spirulina compared with US and lower than unsupplemented animals at 24 and 34 h for Cr-EDTA and Yb, respectively. Spirulina could be provided safely at much higher N intakes than NPN supplements. The results suggest that, at an equivalent RDP supply, Spirulina provided greater increases than US in MCP production, EMCP and feed intake of Bos indicus cattle consuming low protein forage and could also be fed safely at higher levels of N intake.

Changes in milk and plasma fatty acid profile in response to fish and soybean oil supplementation in dairy sheep

An effective strategy for enhancing the bioactive fatty acids (FA) in sheep milk could be dietary supplementation with a moderate level of a combination of soybean oil with fish oil (SFO) without negative effects on milk yield and its chemical composition. Thus, the objective of this study was to determine the effects of a moderate forage diet supplementation with SFO on milk chemical composition and FA profile, as well as on plasma FA. Twelve dairy sheep were assigned to two homogenous sub-groups. Treatments involved a control diet without added oil, and a diet supplemented with 23·6 g soybean oil and 4·7 g fish oil per kg dry matter (DM) of the total ration. The results showed that SFO diet had no effect on milk yield and chemical composition. In blood plasma the concentrations oftrans-11C18:2(VA), C18:2n-6, C20:5n-3(EPA) and C22:6n-3(DHA) were significantly higher while those of C14:0, C16:0and C18:0were lower in sheep fed with SFO diet compared with control. The SFO supplementation of sheep diet increased the concentrations of VA,cis-9, trans-11C18:2CLA,trans-10, cis-12, C18:2CLA, EPA, DHA, monounsaturated FA (MUFA), polyusaturated fatty acids (PUFA) andn-3 FA and decreased those of short chain FA (SCFA), medium chain FA (MCFA), the saturated/unsaturated ratio and the atherogenicity index value in milk compared with the control. In conclussion, the SFO supplementation at the above levels in a sheep diet, with moderate forage to concentrate ratio, improved the milk FA profile from human health standpoint without negative effects on its chemical composition.

Milk fat depression induced by dietary marine algae in dairy ewes: persistency of milk fatty acid composition and animal performance responses

Addition of marine algae (MA) to the diet of dairy ruminants has proven to be an effective strategy to enhance the milk content of some bioactive lipids, but it has also been associated with the syndrome of milk fat depression. Little is known, however, about the persistency of the response to dietary MA in sheep. Based on previous experiments with dairy ewes fed sunflower oil plus MA, it was hypothesized that the response might be mediated by time-dependent adaptations of the rumen microbiota, which could be evaluated indirectly through milk fatty acid (FA) profiles. Animal performance and milk FA composition in response to MA in the diet were studied using 36 Assaf ewes distributed in 6 lots and allocated to 2 treatments (3 lots/treatment) consisting of a total mixed ration (40:60 forage:concentrate ratio) supplemented with 25 g of sunflower oil (SO)/kg of dry matter plus 0 (SO; control diet) or 8 g of MA/kg of dry matter (SOMA diet). Milk production and composition, including FA profile, were analyzed on d 0, 6, 12, 18, 24, 34, 44, and 54 of treatment. Diet supplementation with MA did not affect milk yield but did decrease milk fat content. Differences in the latter were detected from d 18 onward and reached -17% at the end of the experiment (i.e., on d 54). Compared with the control diet, the SOMA diet caused a reduction in milk 18:0 and its desaturation product (cis-9 18:1) that lasted for the whole experimental period. This decrease, together with the progressive increase in some putative fat synthesis inhibitors, especially trans-10 18:1, was related to the persistency of milk fat depression in lactating ewes fed MA. Additionally, inclusion of MA in the diet enhanced the milk content of trans-11 18:1, cis-9,trans-11 18:2, and C20-22 n-3 polyunsaturated FA, mainly 22:6 n-3. Overall, the persistency of the responses observed suggests that the ruminal microbiota did not adapt to the dietary supply of very long chain n-3 polyunsaturated fatty acids.

Fatty acid composition and bacterial community changes in the rumen fluid of lactating sheep fed sunflower oil plus incremental levels of marine algae

Supplementation of ruminant diets with plant oils and marine lipids is an effective strategy for lowering saturated fatty acid (FA) content and increasing the concentration of cis-9,trans-11 conjugated linoleic acid and long-chain n-3 FA in ruminant milk. However, changes in populations of ruminal microorganisms associated with altered biohydrogenation of dietary unsaturated FA are not well characterized. Twenty-five lactating Assaf ewes were allocated at random to 1 of 5 treatments composed of dehydrated alfalfa hay and concentrates containing no additional lipid (control), or supplemented with 25 g of sunflower oil and 0 (SO), 8 (SOMA(1)), 16 (SOMA(2)), or 24 (SOMA(3)) g of marine algae/kg of diet dry matter. On d 28 on diet, samples of rumen fluid were collected for lipid analysis and microbial DNA extraction. Appearance and identification of biohydrogenation intermediates was determined based on complementary gas chromatography and Ag+-HPLC analysis of FA methyl esters. Total bacteria and the Butyrivibrio group were studied in microbial DNA by terminal RFLP analysis, and real-time PCR was used to quantify the known Butyrivibrio bacteria that produce trans-11 18:1 or 18:0. Dietary supplements of sunflower oil alone or in combination with marine algae altered the FA profile of rumen fluid, which was associated with changes in populations of specific bacteria. Inclusion of marine algae in diets containing sunflower oil resulted in the accumulation of trans 18:1 and 10-O-18:0 and a marked decrease in 18:0 concentrations in rumen fluid. At the highest levels of supplementation (SOMA(2) and SOMA(3)), marine algae also promoted a shift in ruminal biohydrogenation pathways toward the formation of trans-10 18:1 at the expense of trans-11 18:1. Changes in the concentration of biohydrogenation intermediates were not accompanied by significant variations in the abundance of known cultivated ruminal bacteria capable of hydrogenating unsaturated FA. However, certain bacterial groups detected by terminal RFLP (such as potentially uncultured Lachnospiraceae strains or Quinella-related bacteria) exhibited variations in their relative frequency consistent with a potential role in one or more metabolic pathways of biohydrogenation in the rumen.

Feeding docosahexaenoic acid to pigs reduces blood triglycerides and induces gene expression for fat oxidation

Meadus, W. J., Duff, P., Rolland, D., Aalhus, J. L., Uttaro, B., and Dugan, M. E. R. 2011. Feeding docosahexaenoic acid to pigs reduces triglycerides in blood and induces gene expression for fat oxidation in liver and adipose but not in muscle. Can. J. Anim. Sci. 91: 601–612. The essential fatty acids required in diets of humans are linoleic acid (18:2n-6:LA) and α-linolenic acid (18:3n-3: ALA), and these can be elongated and desaturated to form long-chain omega-6 or omega-3, respectively. Even though not considered essential, consumption of long-chain omega-3 fatty acid is recommended for health benefits, including protection against cardiovascular disease. The omega-3 fatty acid, docosahexanoic acid (DHA), was supplemented in pig diets as a dried biomass of the microalgae Schizochytrium to see if there are unique physiological changes associated with DHA feeding. Pigs were fed a diet with 330 mg (low), 3600 mg (medium) or 9400 mg (high) DHA per day for the last 25 d before slaughter at market weight (∼110 kg). Blood triglycerides (TG) were assayed colormetrically and tissue samples were analyzed for gene expression patterns of RNA by quantitative real-time polymerase chain reaction. Fatty acids were analyzed by gas chromatography. Animal performance appeared to increase with DHA, as shown by a 14% improved feed:gain ratio of 2.74±0.27 (P<0.05). Blood triglycerides were reduced significantly from 0.40±0.23 mM to 0.20±0.09 mM. Pigs accumulated 14 times more DHA in their subcutaneous fat (SQ) (10.67 mg g−1) on the high diet compared with the control diet (0.75 mg g−1). Gene analysis showed that the expression of the fat oxidation biomarkers acyl CoA oxidase 1 (ACOX1), peroxisome proliferator-activated receptors alpha (PPARα) and gamma (PPARγ) were stimulated in the SQ and liver. The delta-6 desaturase (D6D) and elongase (Elov5), which are genes involved in the endogenous synthesis of DHA, were unchanged. Fatty acid synthase (FASN) was stimulated in the liver and muscle of pigs on the high DHA diet. Analysis of gene transcription activity suggested fat metabolism was stimulated in the liver and SQ fat, but the genes involved in the endogenous production of DHA remained unchanged.

Algal biorefinery-based industry: an approach to address fuel and food insecurity for a carbon-smart world

Food and fuel production are intricately interconnected. In a carbon-smart society, it is imperative to produce both food and fuel sustainably. Integration of the emerging biorefinery concept with other industries can bring many environmental deliverables while mitigating several sustainability-related issues with respect to greenhouse gas emissions, fossil fuel usage, land use change for fuel production and future food insufficiency. A new biorefinery-based integrated industrial ecology encompasses the different value chain of products, coproducts, and services from the biorefinery industries. This paper discusses a framework to integrate the algal biofuel-based biorefinery, a booming biofuel sector, with other industries such as livestock, lignocellulosic and aquaculture. Using the USA as an example, this paper also illustrates the benefits associated with sustainable production of fuel and food. Policy and regulatory initiatives for synergistic development of the algal biofuel sector with other industries can bring many sustainable solutions for the future existence of mankind.

Comparative studies on the metabolism of linoleic acid by rumen bacteria, protozoa, and their mixture in vitro

Linoleic acid was differentially catabolized by the various rumen microbial fractions, such as rumen bacteria (B), protozoa (P), and their mixture (BP). The predominant isomer of conjugated linoleic acids (CLA) synthesized by B, P, and BP from linoleic acid was 9c11t-CLA. The formation of 9c11t-CLA was higher (P < 0.05) in P suspension (53.6 μg/mg microbial nitrogen) compared with B (38.3 μg/mg microbial nitrogen) and BP (28.8 μg/mg microbial nitrogen) suspensions by 12 h of incubation. The second most abundant CLA isomer was 10t12c. The accumulation of 10t12c-CLA in BP suspension was 2.3 times lower (P < 0.05) than that in B suspension (84.8 μg/mg microbial nitrogen) by 12 h of incubation. The accumulation of 10t-18:1 in BP suspension during 6- and 12-h incubation periods were not different (P > 0.05) than that in B suspension (6.8 and 14.0 μg/mg microbial nitrogen, respectively). However, the accumulation of 11t-18:1 in BP suspension at 6- and 12-h incubations were 2.7 and 3.3 times higher (P < 0.05), respectively, than that in B suspension. There were no significant accumulations of 11t-18:1, 10t-18:1, and 18:0 in P suspension throughout the incubation period. It was concluded that B, P, and BP metabolized linoleic acid to different isomers of CLA, whereas B, including BP, was only capable of biohydrogenating the CLA isomers to 18:0 by the reduction of 18:1 isomers. P was incapable of biohydrogenating LA, but its association with B in the BP suspension altered the biohydrogenation of LA significantly compared with B alone.

Effect of inoculated corn silage enriched with sunflower oil on rumen fermentation and lipid metabolism in an artificial rumen (RUSITEC)

BACKGROUND

Some rumen isolates are able to produce conjugated linoleic acid (CLA) from linoleic acid (LA) in vitro. Effects of providing diets containing corn silage (CS) and lucerne hay to an artificial rumen (RUSITEC) in which the corn was not inoculated (CS), or inoculated with Lactobacillus plantarum CCM 4000 (CS + LP), Lactobacillus fermentum LF2 (CS + LF) or Enterococcus faecium CCM 4231 (CS + EF) and supplied with sunflower oil (SO; 30 g kg(-1); w/w) on rumen metabolism were examined.

RESULTS

The SO affected the outputs of all fatty acids. TVA output of uninoculated CS with SO was lower as compared to inoculated CS. The interaction of the CS x SO in the daily output of TVA was detected (P < 0.001). The biohydrogenation of oleic, linoleic, alpha-linolenic and total fatty acids was influenced by SO (P < 0.05 and P < 0.001).

CONCLUSION

Inoculated silage induces changes in the rumen metabolism which might be related to differences observed in the extent of rumen BH of PUFA in RUSITEC. SO supplementation might positively enhances the production of some rumen intermediates; however, relationships between inoculated silages and oil supplementation can be presumed in the daily production of trans-vaccenic acid.

Studies on the production of conjugated linoleic acid from linoleic and vaccenic acids by mixed rumen protozoa

The present study was designed to investigate the capability of mixed rumen protozoa to synthesize conjugated linoleic acid (CLA) from linoleic (LA) and vaccenic acids (VA). Rumen contents were collected from fistulated cows. The protozoal fraction was separated and washed several times with MB9 buffer and then resuspended in autoclaved rumen fluid. The suspensions were anaerobically incubated up to 18 h at 38.5 degrees C with substrates in the presence (P-AB) or the absence of antibacterial-agents (P-No-AB). Neither P-AB nor P-No-AB suspensions were capable of producing CLA from VA (11t-18:1). Linoleic acid was catabolized by P-No-AB to a greater extent than P-AB. Different isomers of CLA were synthesized by P-AB from LA. The 9c11t-CLA was predominant. Thirty seven percent of the maximum accumulated 9c11t-CLA was found in the P-AB suspension as early as 0.1 h into the incubation period. Accumulation of 10t12c-CLA in P-AB suspension was approximately 10.0 times lower than that of 9c11t-CLA. There were no significant productions of VA, 10t-18:1, and 18:0 in P-AB compared with the control, indicating that rumen protozoa have no ability to biohydrogenate CLA isomers. On the other hand, the concentrations of 10t-18:1, VA, and 18:0 in P-No-AB were greater (P < 0.05) compared with those in P-AB, indicating the role of symbiotic bacteria associated with P-No-AB in biohydrogenating CLA isomers. We concluded that mixed rumen protozoa are capable of synthesizing CLA from LA through isomerization reactions. However, they are incapable of metabolizing CLA further. They are also incapable of vaccenic acid biohydrogenation and/or desaturation.