Effects of sunflower oil infusions of Asparagopsis taxiformis on in vitro ruminal methane production and biohydrogenation of polyunsaturated fatty acids

Asparagopsis taxiformis inhibits ruminal methane (CH4) production due to its bromoform (CHBr3) content. The immersion of A. taxiformis in edible vegetable oils allows the extraction and stabilization of the highly volatile CHBr3 in the oil phase. The objectives of this study were to explore the effects of adding sunflower oils with increasing concentrations of CHBr3 on in vitro ruminal methanogenesis and biohydrogenation. Five batches of 48-h in vitro incubations were performed in 14 fermentation bottles, using rumen inocula collected shortly after the slaughter of young crossbred bulls and 1 g of dry matter (DM) from a total diet of mixed feed without added oil (control) or with 60 μL of sunflower oil per gram of DM as the substrate. The treatments were the CHBr3 content in the oil added: 0 μg (B0), 25 μg (B25), 50 μg (B50), 75 μg (B75), 100 μg (B100), and 150 μg (B150) of CHBr3 per gram of substrate DM. Organic matter (OM) degradability, total gas, CH4, volatile fatty acids (VFA), long-chain fatty acids, and dimethyl acetals (DMA) were analyzed at the end of each incubation. Data were analyzed with a model considering the treatments as the fixed effect and the run as a random block and using orthogonal contrasts. Degradability of OM was higher in the control group and was unaffected by CHBr3 concentration. Total gas production per gram of degraded OM was unaffected by treatments and averaged 205 ± 29.8 mL/g. Methane (mL) production decreased linearly with increasing CHBr3 concentrations, with 33%, 47%, and 87% reductions for B75, B100, and B150, respectively. Total VFA concentration was unaffected by oil inclusion but was reduced by 20% in CHBr3-containing treatments, although without any dose-response pattern. The molar percentage of acetate decreased linearly, whereas propionate and butyrate increased linearly with the increasing CHBr3 dosage. Including oil in the diet decreased the branched-chain fatty acids and DMA content. Increasing CHBr3 concentrations did not affect branched-chain fatty acids, but linearly increased most of the identified DMA. Adding oil to the control diet increased the 18:2n-6, whereas increasing the concentration of CHBr3 had no effect on 18:2n-6 but decreased linearly the 18:0 and increased the trans-18:1 isomers. The results obtained provide evidence that oil immersions of A. taxiformis can successfully inhibit ruminal production of CH4 in vitro at doses of 100 and 150 μg/g DM, and simultaneously modulate biohydrogenation.

Nutritional value of meat lipid fraction obtained from mallard duck (Anas platyrhynchos) reared in semiextensive conditions for hunting purposes

The mallard duck or wild duck (Anas platyrhynchos) is the world's most widespread and numerous dabbling duck, being traditionally hunted across many countries in Europe and North America. This study aims to provide a detailed characterization of mallard duck's meat lipid fraction obtained from farmed specimens, reared for hunting purposes, under semiextensive conditions. The mallard's duck meat total lipid content averaged 2.0 and 4.26 g/100 g of fresh meat in breast and leg meat portions, and its meat comprised 23 individual fatty acids (FA) and 3 dimethylacetals (DMA), independently of the sex or meat portion. The oleic (C18:1 cis-9), palmitic (C16:0), stearic (C18:0), linoleic (C18:2n-6), arachidonic (C20:4n-6), palmitoleic (C16:1 cis-9), and cis-vaccenic (C18:1 cis-11) acids were the predominant FA (representing >1% of total fatty acids in both breast and leg meat portions and independently of the sex), and together, these 7 fatty acids were accountable for 92.4 to 96.5% of total FA plus DMA in mallard duck meat. The monounsaturated, saturated and polyunsaturated fatty acids were accountable for 40.4, 35.0, and 21.0% of total FA plus DMA in breast and 54.6, 38.7, and 5.7% of total fatty acids in leg, while total DMA were liable for 3.6 and 0.9% of total FA plus DMA in breast and leg, respectively. The mallard duck meat total cholesterol content averaged 49.8 and 57.1 mg/100 g of fresh meat for breast and leg meat portions. Five tocochromanols were quantified in mallard duck meat, affording it with a total vitamin E content of 5.48 and 3.63 µg/g of fresh meat in breast and leg portions. The sex had no influence (P > 0.05) on mallard's duck meat lipid composition, but meat portion had a strong influence on mallard's duck meat lipid composition, influencing total lipid, total cholesterol, total vitamin E contents, FA partial sums, FA ratios (exception made for the n-6/n-3 ratio), and all nutritional lipid indices. The breast meat presented lower total lipid and total cholesterol contents, better FA ratios and nutritional quality indices and higher vitamin E content, being regarded as a healthier meat than leg. The study presented herein shows that mallard duck production in semiextensive conditions, similar to those used herein, could be used for the production of mallard duck beyond hunting. A production of duck's meat under natural or organic production practices, oriented to a market niche within the gourmet/organic markets.

Nannochloropsis oceanica microalga feeding increases long-chain omega-3 polyunsaturated fatty acids in lamb meat

To test the hypothesis that lambs fed freeze-dried Nannochloropsis oceanica (NO) biomass will have a higher deposition of EPA in tissues than those fed other Nannochloropsis EPA-sources, we fed 28 lambs with one of four diets: i) C, control, without EPA; ii) O, with 1.2% Nannochloropsis oil; iii) SD, with 12.3% spray-dried NO biomass; iv) FD, with 9.2% freeze-dried NO biomass. Dry matter intake, growth, tissues fatty acid composition, oxidative stability and sensory traits of the resultant meat were evaluated. The EPA was highest in tissues of lambs fed SD and FD compared with O but was similar between SD and FD. Total trans-18:1 did not differ among treatments, but the t10/t11-18:1 ratio decreased with all EPA containing diets. EPA diets were also supplemented with Vitamin E preventing the lipid oxidation in EPA-enriched meat and the meat sensory traits were not affected although occasionally some off-flavours were detected in FD meat.

The effects of improving low dietary protein utilization on the proteome of lamb tissues

Cistus ladanifer L. is a common shrub endemic to the Mediterranean region with high levels of condensed tannins (CT). CT form complexes with dietary protein resisting microbial degradation in the rumen, which enhances dietary protein utilization in ruminant diets. The objective of this study was to evaluate the utilization of CT in the diet of lambs on the proteomes of muscle, hepatic and adipose tissues. Twenty-four Merino Branco ram lambs were randomly allocated to three treatments (n = 8): C - control (160 g crude protein (CP)) per kg DM, RP - reduced protein (120 g CP/kg DM); and RPCT - reduced protein (120 g CP/kg DM) treated with CT extract. At the end of the trial, lambs were slaughtered and the longissimus lumborum muscle, hepatic and peri-renal adipose tissues sampled. A two-way approach was used for proteomic analysis: 2D-DIGE and nanoLC-MS. In the muscle, C lambs had lower abundance proteins that partake in the glycolysis pathway than the lambs of other treatments. Control lambs had lower abundance of Fe-carrying proteins in the hepatic tissue than RP and RPCT lambs. The latter lambs had highest abundance of hepatic flavin reductase. In the adipose tissue, C lambs had lowest abundance of fatty-acid synthase. SIGNIFICANCE: soybean meal is an expensive feedstuff in which intensive animal production systems heavily rely on. It is a source of protein extensively degraded in the rumen, leading to efficiency losses on dietary protein utilization during digestion. Protection of dietary protein from extensive ruminal degradation throughout the use of plants or extracts rich in CT allow an increase in the digestive utilization of feed proteins. In addition to enhance the protein digestive utilization, dietary CT may induce other beneficial effects in ruminants such as the improvement of the antioxidant status.

Effect of immunocastration and caponization on fatty acid composition of male chicken meat

Recently, immunocastration with Improvac (ImmC). has been tested in broilers and a considerable reduction in serum testosterone concentration (reduced by 79% compared to roosters) was observed. The aim of this study was to evaluate the effect of immunocastration on meat fatty acid (FA) composition and its comparison with caponized and intact males (roosters). The study was conducted with 3 experimental groups: control group (roosters), the group of birds submitted to surgical caponization (SurgC), and the group of birds submitted to immunocastration with Improvac. The comparison of breast meat partial FA sums of castrated (SurgC and ImmC) with control birds (roosters) revealed that castrated birds showed significantly higher content of n-3 polyunsaturated fatty acids (n-3 PUFA) than control birds (1.76 vs. 1.46 g/100 g of total FA; superiority of 20.2%), which has contributed to the occurrence of significant differences on both the n-6/n-3 ratio and the atherogenicity index (AI). In contrast, on leg meat portion, castrated birds displayed higher contents of both total saturated and monounsaturated fatty acids (SFA and MUFA, with 2.2 and 4.1% more, respectively) and lower total n-6 PUFA content (8.3% less) than was observed in control birds, which contributed to significant differences in the AI index. On the other hand, the comparison of breast meat portion from SurgC with ImmC showed that immunocastration contributed to lower total SFA and higher total n-6 PUFA, which have contributed to significant differences on both Polyunsaturated/Saturated (P/S) and n-6/n-3 ratios. Whereas, on leg meat portion no significant differences were observed on partial sums and a single difference was observed on the thrombogenicity index. Immunocastration of broilers has contributed to minor changes in the FA profile, but has improved the overall lipid quality indexes in both breast and leg meat portions. Therefore, immunocastration could be applied as an alternative method to caponization without negative consequences in meat FA profile.

The reduction of starch in finishing diets supplemented with oil does not prevent the accumulation of trans-10 18:1 in lamb meat

The experiment was conducted to test the hypothesis that the replacement of cereal with low-starch feed ingredients in lambs' finishing diets supplemented with oils could prevent the accumulation of -10-18:1 in meat. Forty lambs were fed 1 of 4 diets supplemented with soybean oil (5.9%) and fish oil (1%) for 6 wk before slaughter. The control (CON) diet contained 43% barley, and in the other diets, barley was completely replaced by dehydrated citrus pulp (DCP), dehydrated sugar beet pulp (DBP), or soybean hulls (SH). Growth performance, feed intake, and carcass and meat quality traits were analyzed. At slaughter, LM samples were collected for gene expression evaluation, and 3 d after slaughter, LM and subcutaneous (s.c.) fat samples were collected for fatty acid analysis. None of the diets affected meat quality, but the DCP diet reduced ADG ( < 0.05) and the DCP and SH diets decreased the feed-to-gain ratio ( < 0.01). The DCP diet increased ( < 0.05) the risk of parakeratosis and the severity of the lesions. Moreover, the DBP treatment led to increased a* (redness) and b* (yellowness) in s.c. fat compared with the CON treatment ( < 0.05). The lipid content of LM did not differ ( > 0.05) with treatment and averaged 34.4 g/kg of meat. Diets had no effect ( > 0.05) on SFA, PUFA, and -MUFA sums and on the -6:-3 ratio in both LM and s.c. fat. A lower expression of fatty acid synthase (FASN) was found with the DCP treatment than with the other treatments ( < 0.001). All treatments showed a high accumulation of -10-18:1, averaging 91 mg/g fatty acid in LM and 147 mg/g fatty acid in s.c. fat. The concentration of -11-18:1 in the tissues was considerably lower than that of -10-18:1, and thus the -10-18:1:-11-18:1 ratio was above 3 with all treatments. Despite this, the SH diet clearly promoted a larger deposition of -11-18:1 and -9,-11-18:2 in tissues compared with the other treatments. () gene expression and SCD activity index in LM were reduced with the SH diet compared with the CON and DCP diets. Overall, these results clearly showed, for the first time, that low-starch/high-NDF diets are not able to prevent the establishment of -10 shifted rumen biohydrogenation pathways, evaluated by the deposition of biohydrogenation intermediates in lamb meat and fat.

Growth performance, carcass and meat quality of lambs supplemented with increasing levels of a tanniferous bush (Cistus ladanifer L.) and vegetable oils

The effects of dietary inclusion of Cistus ladanifer L. (CL) and a vegetable oil blend were evaluated on growth performance,carcass and meat quality of fifty four lambs that were assigned to 9 diets, corresponding to 3 levels of CL(50, 100 and 200 g/kg DM) and 3 levels of oil inclusion (0, 40 and 80 g/kg DM). Treatments had no effects on growth rate. Oil depressed dry matter intake (P = 0.017), carcass muscle (P = 0.041) and increased (P = 0.016) kidney knob channel fat. Chemical and physical meat quality traits were not affected by treatments. Off-flavour perception was higher for 8% of oil (P b 0.001). The level of 100 g/kg DM of CL inclusion improved meat stability after 7 days of storage. Supplementation with linseed and soybean oils (2:1) was a good approach to improve meat nutritional value from feedlot lambs, increasing total n-3 PUFA.

Effect of reduced dietary protein and supplementation with a docosahexaenoic acid product on broiler performance and meat quality

1. Chicken breast meat is a lean meat due to its low content of intramuscular fat (IMF) resulting in an overall lower acceptability by consumers due to a decrease in juiciness, flavour and increased chewiness. Recently, studies performed in pigs suggested the possibility of increasing IMF by decreasing dietary crude protein (CP) content, an effect possibly mediated through an increased lipogenesis. 2. Dietary supplementation with lipids rich in omega 3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) may modulate an increase in the content of these fatty acids in meat from monogastric animals and, thus, promote the daily intake of n-3 LC-PUFA by humans. 3. LC-PUFA are very susceptible to oxidation, resulting in off-flavours that affect meat quality and consumers' acceptability. 4. This trial was conducted to assess the effect of reducing dietary CP, from 21% to 17%, on chicken's meat IMF content and, simultaneously, to evaluate if a complementary supplementation with a proprietary n-3 LC-PUFA source (DHA Gold™) could improve meat quality. These effects were assessed by measuring productive performance and meat quality, oxidative stability, sensory traits and fatty acid profile. 5. A reduction in CP content of broiler diets, from 21% to 17%, balanced for lysine, improved performance while it was not sufficient to increase IMF content in chicken meat. In contrast, DHA Gold™ supplementation had a positive impact both in broiler productive parameters and in meat fatty acid profile. 6. In addition, incorporation of 7.4% of DHA Gold™ in the diet promoted carcass yield but negatively affected chicken meat acceptability by consumers, due to a decrease of meat oxidative stability. 7. Overall the data suggest that neither a dietary supplementation with DHA Gold™ nor a reduction in CP have a direct positive effect in the levels of IMF present in broiler meat.

Direct supplementation of diet is the most efficient way of enriching broiler meat with n-3 long-chain polyunsaturated fatty acids

1. Concentrations of beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) in poultry meat can be improved by increasing the concentration of n-3 PUFA in poultry diets. 2. A decrease in flavour quality is, however, usually associated with the dietary supplementation with n-3 PUFA, which is due to the susceptibility of PUFA to oxidation. 3. This experiment was conducted to study the effects of introducing two different n-3 fatty acid sources (extruded linseed and DHA Gold™, a proprietary algal product rich in docosahexaenoic acid), either separately or together, on broiler productive performance, and meat quality, oxidative stability, sensory traits and LC-PUFA profile. 4. Birds given the algal product displayed better productive performances than animals from other groups. 5. The data revealed an improvement in the fatty acid nutritional value of meat from birds receiving the algal product and an inefficient conversion of α-linolenic acid (LNA) into LC-PUFA. 6. Metabolisation of LNA in vivo is not sufficient to improve meat quality in n-3 LC-PUFA and direct supplementation of the diet with n-3 LC-PUFA is a better alternative to modulate an increase in beneficial fatty acids of broiler meat. 7. The overall acceptability of meat was negatively affected by the dietary supplementation with 7.4% of DHA, in contrast to the supplementation with 3.7% of DHA, which showed to be efficient in improving LC-PUFA meat content without affecting its sensory properties.

Effect of corn supplementation of grass finishing of Holstein bulls on fatty acid composition of meat lipids

Finishing Holstein young bulls exclusively on pasture generally results in very lean carcass and meat, but corn supplementation is expected to simultaneously improve carcass traits and intramuscular lipids (IML). The expected increase in IML would allow for a larger 18:2c9,t11 (CLA) deposition in meat without affecting the n-3 PUFA present in LM phospholipids (PL). Holstein bulls (n = 33) with initial BW of 423 ± 52.4 kg reared exclusively on pasture were assigned to 1 of 3 finishing period (85 d) diets: finished exclusively on pasture (P0) or finished on pasture and individually supplemented with 4 (P4) or 8 kg/d (P8) of ground corn. Final BW (546 ± 56.3 kg) was not affected (P > 0.05) by corn supplementation, but ADG increased (P < 0.01) with the increasing corn supplementation level from 1.23 kg/d for P0 to 1.44 kg/d for P4 and to 1.67 kg/d for P8. Subcutaneous fat depth in P0 bulls was 0.8 mm and increased (P < 0.001) in both P4 (2.9 mm) and P8 (2.7 mm) bulls, but no difference (P = 0.73) was observed between P4 and P8 bulls. Similarly, the IML increased with corn supplementation, from 1.84 g/100 g muscle in P0 to 2.96 in P4 and to 3.24 in P8, but no difference (P = 0.55) was found between P4 and P8 bulls. Corn supplementation decreased (P < 0.01) 18:1t11 in neutral lipids (NL) but not 18:2c9,t11 (P > 0.34). The 18:1t10 (mg/g total NL fatty acid [FA] ± SEM) were 2.5 ± 0.13 in P0, 5.5 ± 1.68 in P4, and 14.8 ± 3.18 in P8 bulls, being greater in P8 compared with P4 (P = 0.02). Total FA in muscle PL and SFA were unaffected, but increasing corn supplementation resulted (P < 0.001) in an increase of 18:2n-6 in PL by replacement of mostly the 18:1c9 and 18:3n-3. Notably, the total number of cis double bonds present in FA of PL remained constant (P = 0.74) with corn supplementation. Compared with P0, corn supplementation maintained (P > 0.05) the high n-3 PUFA content in meat (mg/100 g meat) and increased the 18:2c9,t11 (P = 0.028) and 18:1c9 (P < 0.001). However, increasing corn supplementation from 4 to 8 kg/d increased the 18:1t10 (P = 0.031) and had no effect on 18:2c9,t11. Therefore, supplementing grass-finished Holstein bulls with moderate amounts of ground corn (4 kg/d) increased carcass fat cover and IML, maintained n-3 PUFA, and increased 18:2c9,t11 content in meat, whereas greater corn supplementation (8 kg/d; P8) resulted in no further improvements.

Effects of body condition and leptin on the reproductive performance of Lusitano mares on extensive systems

The aim of this study was to investigate the effects of body condition (BC), BC changes, and plasma leptin concentrations on the reproductive performance of Lusitano broodmares on extensive systems. Data from 119 mares (ranging from 4 to 22 years of age) were collected over a period of four consecutive breeding seasons. Each case was considered as one foaled mare bred in 1 year. Body condition changes at conception (ΔBCScon) showed a strong effect on fertility at the first two postpartum estrous cycles and a significant interaction with body condition score at conception (BCScon) was observed (P < 0.01). The best fertility results were obtained with positive and greater ΔBCScon. The best predictive value of fertility (91%) was achieved when the BCScon was 3.0 and ΔBCScon was 0.375. Global foaling rate for the 4-year period was 74.5%. Mean foaling interval and gestation length were, respectively, 368.0 ± 2.8 and 340.3 ± 1.0 days. Gestation length was influenced by the month of foaling (P < 0.05) and decreased as mares got older (P < 0.01). The number of estimated estrous cycles per live foal was 1.78 ± 0.12, including foal heat ovulation. Leptin was correlated with BCS (0.41; P < 0.001), but in the present study, plasma leptin concentrations on late gestation and early lactation did not influence fertility results. At 90 days of age, lower growth performances were obtained in foals which dams presented negative BCS changes on the first 3 months of lactation (P < 0.05). In conclusion, BC changes at early postpartum period influence the reproductive efficiency of broodmares and the growth of their suckling foals. These findings are important to help breeders on management options concerning feeding strategies in the Lusitano production systems and others under similar conditions.

Effect of pig breed and dietary protein level on selected fatty acids and stearoyl-coenzyme A desaturase protein expression in longissimus muscle and subcutaneous fat

The aims of the study were 1) to investigate effects of a low protein diet on fatty acids content and composition of the LM and subcutaneous adipose tissue in 3 genetically diverse breeds, Large White × Landrace, Alentejano, and Bizaro, and 2) to determine whether the effect of the low protein diet of fatty acid composition is associated with dietary modulation of stearoyl-CoA desaturase (SCD) protein expression. The experiments were conducted on 12 Large White × Landrace, 12 Alentejano, and 10 Bízaro female and male pigs. The average animal BW at the beginning of experiments was 40.8, 40.7, and 38.3 kg for Large White × Landrace, Alentejano, and Bízaro, respectively, and the BW of animals at slaughter was 90 kg. The diets contained 202 or 169 g/kg DM of CP (high and low protein diets, respectively) and were balanced in essential AA. The diets were fed until the animals reached 90 kg BW (approximately 73 d). It was established that Large White × Landrace pigs had a less (P = 0.001) total fatty acid content in subcutaneous adipose tissue when compared with Alentejano and Bízaro and less (P < 0.001) intramuscular fat (IMF) content when compared with Alentejano. There was a positive relationship between SCD protein expression in the LM and MUFA content (r = 0.627, P = 0.029) and SCD protein expression and total muscle fatty acids content (r = 0.725, P = 0.008) in Large White × Landrace but not in Alentejano and Bizaro breeds. It has been suggested that SCD protein expression is associated with regulation of fat deposition only in breeds with genetic predisposition to a low IMF content.

The increased intramuscular fat promoted by dietary lysine restriction in lean but not in fatty pig genotypes improves pork sensory attributes

Sixty entire male pigs from 2 distinct genotypes (30 Alentejano purebred, an autochthonous fatty genotype, and 30 commercial crossbred pigs, a lean genotype) were used to investigate the effects of dietary CP reduction and low-Lys levels on growth performance, carcass traits, and meat quality. Pigs with 59.9 ± 2.0 kg BW were randomly assigned within each genotype to 1 of 3 diets [normal CP diet (control), reduced CP diet adjusted for Lys (RPDL), and reduced CP diet not adjusted for Lys (RPD)] as a 2 × 3 factorial arrangement of treatments with 10 individually fed pigs per treatment. Pigs were slaughtered at 93.4 ± 2.4 kg BW. The results showed that intramuscular fat (IMF) content of longissimus lumborum muscle was greater in Alentejano than crossbred pigs (5.0 vs. 2.4%). The RPDL had no effect on IMF content, ADG, backfat thickness, and loin weight in both genotypes. The RPD promoted the increase (P < 0.05) in IMF content in crossbred (∼50%) but not Alentejano pigs, which indicates that Lys restriction can mediate the effect of RPD. Within crossbred pigs, meat obtained from pigs fed RPD had an increased IMF content (+1.3%) and a tendency for greater sensory scores (tenderness, juiciness, flavor, and acceptability) than those fed the control. The IMF content was positively correlated to flavor in Alentejano genotype (P < 0.05) but not in crossbred pigs. Alentejano and crossbred pigs had a greater tendency to deposit 18:1c9 and SFA, respectively. Despite the contribution of fatty acid composition to flavor, its influence on pork acceptability was more noticeable in crossbred than Alentejano pigs. In conclusion, the increased IMF promoted by dietary CP reduction in lean but not in fatty pig genotypes during the growing-finishing period is likely due to Lys limitation, which seems to enhance eating quality of pork.

Identification of C18 intermediates formed during stearidonic acid biohydrogenation by rumen microorganisms in vitro

In vitro batch incubations were used to study the rumen biohydrogenation of unsaturated fatty acids. An earlier study using increasing supplementation levels of stearidonic acid (18:4n-3), revealed that the rumen microbial population extensively biohydrogenates 18:4n-3 after 72 h of in vitro incubation, though several intermediates formed were not completely characterized. Therefore, in the present study, samples were reanalyzed in order to identify the 18:2, 18:3 and 18:4 biohydrogenation intermediates of 18:4n-3. Gas-liquid chromatography coupled to mass spectrometry was used to characterize these intermediates. The acetonitrile chemical ionization mass spectrometry of the fatty acid methyl esters derivatives enabled the discrimination of fatty acids as non-conjugated or conjugated biohydrogenation intermediates. In addition, the acetonitrile covalent adduct chemical ionization tandem mass spectrometry yielded prominent ions indicative of the double bond position of the major 18:3 isomers, i.e. Δ5,11,15 18:3. Furthermore, the 4,4-dimethyloxazoline derivatives prepared from the fatty acid methyl esters enabled the structure of novel 18:2, 18:3 and 18:4 biohydrogenation intermediates to be elucidated. The intermediates accumulated in the fermentation media after 72 h of incubation of 18:4n-3 suggest that similar to the biohydrogenation pathways of linoleic (18:2n-6) and α-linolenic (18:3n-3) acids, the pathway of the 18:4n-3 also proceeds with the formation of conjugated fatty acids followed by hydrogenation, although no conjugated dienes were found. The formation of the novel biohydrogenation intermediates of 18:4n-3 seems to follow an uncommon isomerization pattern with distinct double bond migrations.

Genotype x environment interactions for fatty acid profiles in Bos indicus and Bos taurus finished on pasture or grain

A study was conducted to characterize lipid profiles in the M. longissimus thoracis of commercial Brazilian beef and to assess how those profiles are influenced by finishing system, genetic group, and their interaction. Intramuscular fat (IMF) and fatty acid (FA) profiles were determined in 160 bulls of the Bos taurus (n = 75) and Bos indicus (n = 85) genetic groups, finished on pasture (n = 46) or with grain supplementation (n = 114) and slaughtered in a commercial abattoir. Finishing system had a major impact on the deposition of IMF, as well as on the concentration of SFA, PUFA, and their ratio, but genetic groups showed important differences in the ability to convert SFA into cis-9 MUFA and to convert 16:0 into 18:0. When compared with pasture-finished animals, those finished with grain had greater content of IMF and SFA (P < 0.01), similar amounts of MUFA (P > 0.05), and about one-half the amount of PUFA (P < 0.01). Except for MUFA, differences in FA profiles among finishing systems were mostly mediated through their effect on IMF, even though the relationship of IMF with groups of FA differed among finishing systems. Under grain finishing, B. taurus had less SFA and greater MUFA than B. indicus (P < 0.01), but no differences were observed in PUFA (P > 0.05). With pasture-finishing, no differences were observed among the 2 genetic groups in SFA and MUFA (P > 0.05), but PUFA were decreased in B. taurus (P < 0.01). When genetic groups were compared in grain-finishing, B. taurus had a decreased ability for elongation and B. indicus had a decreased aptitude for desaturation of FA. On the other hand, with pasture-finishing a greater deposition of intermediate FA from ruminal biohydrogenation was observed in B. indicus than in B. taurus. Overall, FA profiles were affected more by finishing system in B. indicus than in B. taurus.

Effect of trans-10 cis-12 conjugated linoleic acid on bovine oocyte competence and fatty acid composition

The reproductive performance of dairy cows may be improved by feeding conjugated linoleic acid (CLA) supplements during early lactation. The mechanism of action of t10,c12 CLA is not clearly known. Our objective was to investigate the effect of t10,c12 CLA on oocyte maturation and lipid composition of cumulus oocyte complexes (COC). The developmental potential of oocytes incubated in in vitro maturation (IVM) medium supplemented with t10,c12 CLA to the blastocyst stage and embryo quality were also assessed. In experiment 1, abattoir-derived oocytes were matured in TCM199 + 10% serum supplemented with 100 μM t10,c12 CLA (t10,c12 CLA n = 672) or without it (control n = 672). Mature oocytes were either stained for chromatin configuration or inseminated and cultured for embryo development assessment. In experiment 2, COC and IVM culture media were subjected to fatty acid (FA) analysis prior and after maturation with t10,c12 CLA or without it (control). Total lipids and FA profiles in oocytes, cumulus cells and culture media were determined by gas chromatography. t10,c12 CLA supplementation to IVM medium improved (p = 0.05) embryo quality evaluated morphologically. This effect was associated with t10,c12 CLA presence (3.1 ± 0.7%, p = 0.04) and lower levels of arachidonic acid in FA profile of t10,c12 CLA mature oocytes (immature oocytes = 4.4 ± 1.9%, t10,c12 CLA mature oocytes = 1.0 ± 0.7%, p = 0.05). Differences in myristic and eicotrienoic acids, saturated and unsaturated FA concentrations between oocytes and cumulus cells were detected (p ≤ 0.05). In conclusion, the presence of t10,c12 CLA during maturation interfered on lipid metabolism improving bovine oocyte competence to develop into higher quality embryos.

Restricting the intake of a cereal-based feed in free-range-pastured poultry: effects on performance and meat quality

Pastures are assumed to be good sources of alpha-linolenic acid (ALA) and other bioactive compounds. In this study, we evaluated the effects of restricting the intake of a cereal-based feed on the consumption of a legume-based pasture, and consequently on poultry performance and meat quality. Broilers of the RedBro Cou Nu x RedBro M genotype were fed a cereal-based feed at different intake restriction levels (100, 75, or 50% of ad libitum intake) in portable floorless pens located on a subterranean clover (Trifolium subterraneum) pasture. Control birds were maintained at the same site in identical pens but had no access to pasture. The results revealed that, although the growth rate achieved was below the levels expected for the genotype, restriction of cereal-based feed intake had a significant impact on broiler weight gain and feed conversion while leading to an increase in relative leguminous pasture intake (from 1.6 to 4.9% of the total intake, on a DM basis). In addition, bird performance was positively influenced by pasture consumption. The capacity of ingested pasture to modulate carcass characteristics, broiler meat fatty acid profiles, and the meat content of total cholesterol, tocopherols, and to-cotrienols was investigated in broiler chickens slaughtered on d 64. Pasture intake decreased carcass yield (P < 0.05) and meat pH (P < 0.001) and improved breast skin pigmentation (P < 0.001). Consumption of the leguminous pasture had a marginal effect in the vitamin E profiles and cholesterol contents of broiler meat (P < 0.05), although it significantly affected the meat fatty acid profile. Although pasture intake did not influence the linoleic acid content of poultry meat, the levels of n-3 polyunsaturated fatty acids in breast meat [ALA (P < 0.001), eicosapentaenoic acid (P < 0.001), docosapentaenoic acid (P < 0.001), and docosahexaenoic acid (P < 0.001)] were significantly greater in birds consuming the leguminous biomass. Overall, the data suggest an important deposition of ALA and some conversion of ALA to its derivatives in pastured broilers subjected to a restriction of cereal-based feed.

Effects of grass silage and soybean meal supplementation on milk production and milk fatty acid profiles of grazing dairy cows

The effects of supplementation with grass silage and replacement of some corn in the concentrate with soybean meal (SBM) on milk production, and milk fatty acid (FA) profiles were evaluated in a replicated 4 x 4 Latin square study using 16 dairy cows grazing pasture composed of ryegrass, Kentucky bluegrass, and white clover. Each experimental period lasted for 3 wk. The 4 dietary treatments were PC, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn-based concentrate mixture (96% corn; C); PCSB, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn- and SBM-based concentrate mixture (78% corn and 18% SBM; CSB); SC, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of C concentrate; and SCSB, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of CSB concentrate. The concentrate mixtures were offered twice each day in the milking parlor and were consumed completely. Grass silage supplementation reduced dietary crude protein and concentration of total sugars, and dietary SBM inclusion increased dietary crude protein concentration and decreased dietary starch concentration. Milk yield and energy-corrected milk were increased by SBM supplementation of cows with access to grass silage. Milk protein concentration was lower in cows offered grass silage, regardless of whether SBM was fed. Dietary SBM inclusion tended to increase milk fat concentration. Plasma urea N was reduced by silage feeding and increased by SBM supplementation. Supplementation with grass silage overnight could represent a useful strategy for periods of lower pasture availability. Dietary inclusion of SBM in solely grazing cows had no effects on milk production and composition, exacerbated the inefficient capture of dietary N, and increased diet cost. Grass silage supplementation affected milk FA profiles, increasing both the FA derived from de novo synthesis and those derived from rumen microbial biomass, and decreasing the sum of C18 FA (mostly derived from diet or from mobilization of adipose tissue reserves). Milk fat concentrations of conjugated linoleic acid cis-9, trans-11, vaccenic acid (18:1 trans-11), and linolenic acid (18:3n-3) were unaffected by grass silage supplementation, suggesting that partial replacement of pasture by unwilted grass silage does not compromise the dietary quality of milk fat for humans.

Influence of pasture intake on the fatty acid composition, and cholesterol, tocopherols, and tocotrienols content in meat from free-range broilers

Over the last centuries, Western diets acquired a dramatic imbalance in the ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA) with a concomitant reduction in the dietary proportion of n-3 PUFA. Pastures are a good source of n-3 fatty acids, although the effect of forage intake in the fatty acid profile of meat from free-range chicken remains to be evaluated. In addition, it is unknown if consumer interest in specialty poultry products derived from free-range or organic production systems is accompanied by a greater nutritional quality of these products. In this study, broilers of the RedBro Cou Nu x RedBro M genotype were fed on a cereal-based diet in portable floorless pens located either on subterranean clover (Trifolium subterraneum) or white clover (Trifolium repens) pastures. Control birds were maintained at the same site in identical pens but had no access to pasture. The capacity of ingested forage to modulate broiler meat fatty acid profiles and the meat content of total cholesterol, tocopherols, and tocotrienols was investigated in broiler chicks slaughtered at d 56. The results suggested that pasture intake (<5% DM) had a low impact on the fatty acid and vitamin E homologue profiles of meat from free-range broilers. However, breast meat from birds with free access to pasture presented lower levels of the n-6 and n-3 fatty acid precursors linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), respectively. In spring the levels of eicosapentaenoic acid (20:5n-3) in breast meat were significantly greater in birds consuming pastures, which suggests greater conversion of alpha-linolenic acid into eicosapentaenoic acid in these birds. Finally, when compared with meat from slower-growing genotypes obtained under the conventional European free-range production systems with slaughtering at d 81, meat from birds of the Ross genotype raised intensively and slaughtered at d 35 seemed to have greater nutritional quality.

Muscle fiber and fatty acid profiles of Mertolenga-PDO meat

The influence of phenotype and muscle type on intramuscular total lipids (ITL) neutral lipid (NL) and phospholipid (PL) compositions, cholesterol, α-tocopherol and haem iron contents were evaluated in Semitendinosus (St), Longissimus dorsi (Ld) and Supraspinatus (Ss) muscles from 39 Mertolenga young bulls. The results showed that lipid, α-tocopherol, cholesterol and haemic iron contents were not influenced by phenotype. Furthermore, the individual effect of phenotype was not a significant source of variation on ITL, NL and PL fatty acid composition. Muscle histological traits from Unicolor phenotype (n=13) showed that Ss and Ld muscles exhibited higher proportion of type I (P<0.001) and oxidative fibers (P<0.001) and lower percentages of IIB fibers (P<0.001) than St. The Ss muscle, with higher relative area occupied by oxidative fibers (P<0.05-0.001) than Ld and St, had higher ITL (P<0.001), NL (P<0.001), PL (P<0.05-0.01), α-tocopherol (P<0.001), cholesterol (P<0.01) and haem iron (P<0.001) contents than its counterparts. Muscle type notably affected ITL, as a result of its influence on NL rather than in PL composition.

Cryosurvival of bovine blastocysts is enhanced by culture with trans-10 cis-12 conjugated linoleic acid (10t,12c CLA)

An excessive lipid content in embryo cells is a consequence of embryo culture in the presence of serum which is suggested to be responsible for their high susceptibility to cryopreservation. The objective of the present study was to examine the effects of supplementing serum-containing culture media with trans-10 cis-12 conjugated linoleic acid (10t,12c CLA) on embryo lipid accumulation and its subsequent cryopreservation. Abattoir-derived oocytes were matured and fertilized in vitro (IVF=day 0). On day 1, presumptive zygotes (n=3390) were randomly placed in: (I) (MS), granulosa cell monolayer cultured with M199 and 10% serum; (II) (SCLA), granulosa cell monolayer cultured with M199, 10% serum and 100 microM 10t,12c CLA and (III) (SOF), modified synthetic oviduct fluid, where embryo culture proceeded for 8 days. Cleavage rates or D7/D8 embryo quality did not vary among treatments. D7/D8 embryo production rate was significantly (P<0.001) lower in SOF (17.9+/-1.6%) than in groups MS (29.8+/-2.5%) and SCLA (27.8+/-2.0%). After cytoplasmic lipid droplets observation under Nomarski microscopy, classified embryos were the leanest when cultured in SOF, intermediate in SCLA and the fattest in MS (P<0.02). Post-thawing intact blastocyst rates where significantly higher in the SCLA group (84.7+/-4.1%) than in SOCS (50.3+/-4.8%, P=0.0007) or SOF (65.3+/-6.9%, P=0.03) groups. Post-thawing re-expanding rates were significantly lower when embryos were cultured in MS (34.7+/-3.7%) than in SCLA (63.7+/-5.3%, P=0.0006) or SOF (49.0+/-4.6%, P=0.04). Moreover, re-expanding rates were lower (P=0.05) in SOF than in SCLA cultured embryos. These results clearly show that addition of CLA to serum-containing media reduced lipid accumulation during in vitro culture and significantly improved cryopreservation survival.

Effects of Dietary Protein and Starch on Intake, Milk Production, and Milk Fatty Acid Profiles of Dairy Cows Fed Corn Silage-Based Diets

Feed intake, milk production, and milk fatty acid profiles of dairy cows fed corn silage-based diets with different protein and starch concentrations were measured in a 3-period experiment in a changeover design using 12 Holstein cows. Each experimental period lasted for 3 wk. The diet fed as a total mixed ration consisted of 45% corn silage, 5% coarsely chopped wheat straw, and 50% concentrate, on a dry matter (DM) basis. The 4 treatments, formulated to be isoenergetic and to differ in concentrations of dietary crude protein (CP) and starch (DM basis), were as follows: low CP and low starch (LPLS; 14% CP and 15% starch), low CP and high starch (LPHS; 14% CP and 25% starch), high CP and low starch (HPLS; 16% CP and 15% starch), and high CP and high starch (HPHS; 16% CP and 25% starch). The LPLS treatment led to lower DM intake, milk yield, milk protein concentration, and milk lactose yield, probably due to a shortage of both rumen-degradable protein supply to rumen microbes and glucogenic nutrients to the animal. There were no differences between protein-rich diets and LPHS, suggesting that this diet satisfied the rumen-degradable protein requirements of rumen microbes and did not limit feed intake, and the increased supply of glucogenic nutrients spared AA so that the nutrient requirements of mid lactation dairy cows were met. Further increases in CP concentration increased plasma urea concentration and resulted in decreased efficiency of conversion of dietary N into milk N. Milk fatty acid profiles were affected by starch and protein supply, with starch having the largest effect. Additionally, increasing dietary starch concentration decreased the apparent transfer of dietary polyunsaturated fatty acids to milk, suggesting an increased channeling of fatty acids to adipose tissue. The results further suggest that C(15:0) and C(17:0) are synthesized de novo in animal tissues.

Short communication: The nature of heptadecenoic acid in ruminant fats

Heptadecenoic acid (17:1) is a minor constituent of ruminant fats and its isomeric definition remains undefined in most reports on ruminant milk and intramuscular fat. Samples of milk and intramuscular fat of bovine, ovine, and caprine origin were analyzed by gas chromatography (GC) using 3 capillary columns with and without addition of 17:1 cis-10. Additionally, cis isomers of ovine milk fat samples were isolated as methyl esters by preparative thin-layer chromatography and analyzed by GC. The structural analysis of 17:1 present in samples was achieved by chemical ionization tandem mass spectrometry techniques. The isomer 17:1 cis-9 is the overwhelming heptadecenoic isomer in ruminant milk and intramuscular fat; 17:1 cis-10 is virtually absent. Moreover, current GC methods were able to resolve cis-9 from cis-10 and cis-8 isomers, so reports on 17:1 contents in ruminant fat should define its isomeric composition.