Postgraduate Symposium Long-chain n -3 PUFA: intakes in the UK and the potential of a chicken meat prototype to increase them: Conference on ‘Over- and undernutrition: challenges and approaches’

In Vitro Antioxidant Activities of Plant Polyphenol Extracts and Their Combined Effect with Flaxseed on Raw and Cooked Breast Muscle Fatty Acid Content, Lipid Health Indices and Oxidative Stability in Slow-Growing Sasso Chickens

Adding flaxseed was found to decrease oxidative stability in feed and increase the antioxidant needs of chicken. This has also been associated with a decrease in the nutritional value and oxidative stability of meat if sufficient dietary antioxidants are not included. Furthermore, dietary flaxseed has been explored in fast-growing chickens as such studies are limited with slow-growing chickens. Thus, this study aimed to evaluate the effects of feeding plant polyphenol extracts as an antioxidant alongside flaxseed on fatty acid content, oxidative stability, and lipid health indices in breast muscle of slow-growing Sasso T451A dual-purpose chicken. A total of 126 chickens assigned to six groups (seven replicates of three) were fed on NC (control and no antioxidants), FS (75 g flaxseed and no antioxidants), VE8 (75 g flaxseed and 800 mg vitamin E), TS8 (75 g flaxseed and 800 mg Thymus schimperi), DA8 (75 g flaxseed and 800 mg Dodonaea angustifolia) and CD8 (75 g flaxseed and 800 mg Curcuma domestica) extract per kg diet. Feeding on CD8 and VE8 in raw and TS8, CD8 and VE8 diets in cooked breast muscle increased (p < 0.05) the C22:6n − 3 (DHA) and C20:5n − 3 (EPA) contents compared to the FS diet. Feeding FS increased (p < 0.05) the malondialdehyde (MDA) content in breast muscle, whereas TS8 in cooked and raw and CD8 and DA8 diets in raw breast muscle decreased it (p < 0.05). No added benefit was observed in feeding VE8 over plant extracts in terms of improving fatty acid composition and lipid health indices and reducing lipid oxidation in breast meat.

Effect of feeding strawberry, raspberry and rapeseed oil in rats’ diet on the fatty acid profile of muscle tissue

Currently, alternative plant oils with pro-health properties are sought. The aim of the present study was to investigate the effect of feeding strawberry, raspberry and rapeseed oils in rats’ diet on the fatty acid profile of muscle tissue. Adult rats were randomly divided into 4 groups (n=7) and fed with the addition of rapeseed, raspberry or strawberry seed oil, respectively, or control group. After a 6-week treatment period, the fatty acid profile in m. latisssimus dorsi, was analyzed using gas chromatography. The dietary strawberry or raspberry seed oil led to a significant increase in C-18:2 n-6 ad C-18:3 n-3 level in muscle fat when compared to control group. At the same time, in the group receiving raspberry oil, an unfavorable phenomenon of lowering the EPA content was observed, while a tendency towards a decrease in DHA level was observed in groups supplemented with both raspberry and strawberry oil. Both oils as a source of PUFA n-3 and n-6, increased ALA n-3 and LA n-6 fatty acids in latissimus dorsi muscle, but due to different activity of enzymes taking apart in conversion of polyunsaturated fatty acids to their long chain derivatives in rats, the research on pig model would be advisable.

Effect of freeze-thaw cycles on the physicochemical properties, water-holding status, and nutritional values of broiler chicken drumstick

This study aimed to determine the effects of multiple freeze-thaw (FT) cycles (0, 1, 2, and 4) on the physicochemical properties, water-holding status, and nutritional values of broiler drumsticks. The results showed that L* (lightness) and b* (yellowness) values, thiobarbituric acid-reactive substances, total volatile basic nitrogen, and total viable counts significantly increased but pH values, protein solubility, and sensorial acceptance decreased after four FT cycles (P ˂ 0.05). The decreases in moisture content thawing loss, centrifugation loss, drip loss, and cooking loss indicated that the water-holding capacities of samples subjected to multiple FT cycles were diminished. Results of cell microstructure analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed the occurrence of ruptured muscle cells with decreased fiber diameters and changes in myosin heavy chain band intensity after multiple FT cycles (P ˂ 0.05). As the number of FT cycles increased, the content of total free amino acids and polyunsaturated fatty acids including linoleic (C18:2), linolenic (C18:3), eicosatetraenoic (EPA, C20:5), and docosahexaenoic (DHA, C22:6) acids decreased (P ˂ 0.05). In conclusion, four repeated FT cycles accelerated the deterioration of physiochemical properties, reduced the water-holding status, and considerably impaired sensory characteristics and nutritional values of chicken meat.

Influence of storage and packaging method on chicken breast meat chemical composition and fat oxidation

The aim of this study was to determine the influence of storage conditions and packaging methods on chicken breast meat chemical composition and fat oxidation. In this study, chicken breasts available in retail sale were used for evaluation. The meat packed by three different methods (air packaging-AP, modified atmosphere packaging-MAP, and vacuum packaging-VP) was stored in a cooling room or a commercial display case for 9 D and tested for basic chemical composition, lipid oxidation (TBARS), and fatty acid composition. Meat in MAP during storage in the cooling room was characterized by higher (P ≤ 0.05) TBARS values as compared to meat packaged in AP and VP, respectively. The highest share in the fatty acid profile in chicken breasts was demonstrated by monounsaturated fatty acid, including cis C18:1 (n9 + n11) acid in the range from 31.86 to 34.66%. A high share of polyunsaturated acids was observed, including linoleic (C18:2 cis, cis) acid from 24.50 to 31.22% of all fatty acids. The simple relationship between the changes in the profile of fatty acids in meat packaged using different methods and in storage time was not determined, likely due to the variability of the composition of fatty acids in chicken breasts depending on the sample and the general low level of fat found in the meat.

Long-chain n-3 fatty acids as an essential link between musculoskeletal and cardio-metabolic health in older adults

This narrative review aims to critically evaluate scientific evidence exploring the therapeutic role(s) of long-chain n-3 PUFA in the context of ageing, and specifically, sarcopenia. We highlight that beyond impairments in physical function and a lack of independence, the age-related decline in muscle mass has ramifications for cardio-metabolic health. Specifically, skeletal muscle is crucial in regulating blood glucose homeostasis (and by extension reducing type 2 diabetes mellitus risk) and providing gluconeogenic precursors that are critical for survival during muscle wasting conditions (i.e. AIDS). Recent interest in the potential anabolic action of n-3 PUFA is based on findings from experimental studies that measured acute changes in the stimulation of muscle protein synthesis (MPS) and/or chronic changes in muscle mass and strength in response to fish oil-derived n-3 PUFA supplementation. Key findings include a potentiated response of MPS to amino acid provision or resistance-based exercise with n-3 PUFA in healthy older adults that extrapolated to longer-term changes in muscle mass and strength. The key mechanism(s) underpinning this enhanced response of MPS remains to be fully elucidated, but is likely driven by the incorporation of exogenous n-3 PUFA into the muscle phospholipid membrane and subsequent up-regulation of cell signalling proteins known to control MPS. In conclusion, multiple lines of evidence suggest that dietary n-3 PUFA provide an essential link between musculoskeletal and cardio-metabolic health in older adults. Given that western diets are typically meagre in n-3 PUFA content, nutritional recommendations for maintaining muscle health with advancing age should place greater emphasis on dietary n-3 PUFA intake.

Incidence of White Striping and Its Effect on the Quality Traits of Raw and Processed Turkey Breast Meat

The aim of this study is to evaluate the incidence of white striping abnormality and its consequences on the quality traits of raw and processed turkey breast (chemical composition, color traits, and water holding capacity). In total, about 2300 breasts from 22 flocks were used to assess the incidence and 60 breasts to evaluate the quality traits. Our study showed that the total incidence of moderate and severe white striping was 61.3% out of them, moderate cases were 49.4%. Severe white striped turkey breast exhibited significantly lower protein content (21.1 vs. 23.2 and 23.16%, p<0.05) and higher fat content (2.3 vs. 0.77 and 1.76%, p<0.05) if compared to normal and moderate white striped breast respectively. Moreover, moderate and severe white striped meat showed significantly higher redness (a*) (2.98 and 3.14 vs. 1.48, p<0.05) and yellowness (b*) indexes (7.27 and 7.95 vs. 4.05, p<0.05) than normal meat, respectively.

Fatty acid profile, oxidative stability and sensory quality of breast meat from turkeys fed diets with graded levels of flaxseed oil for different periods of time

The effect of partial or complete substitution (2.5% and 5%, respectively) of flaxseed oil for soybean oil on the fatty acid profile, oxidative stability and sensory quality of turkey breast meat was studied. Turkeys were fed experimental diets for 3, 4, 5 or 6 weeks before being slaughtered at 16 weeks of age. The percentages of α-linolenic acid and eicosapentaenoic acid in the total fatty acid pool of meat were determined by dietary intake and feeding duration. Even a prolonged dietary treatment with 5% flaxseed oil did not significantly increase the thiobarbituric acid reactive substances content of the turkey meat and did not have a detrimental effect on the sensory properties. The recommended n-6 : n-3 polyunsaturated fatty acids ratio (<4 : 1) in turkey meat can be easily achieved by feeding turkeys a diet containing 2.5% flaxseed oil for 3 weeks. To maintain the above ratio and increase eicosapentaenoic acid concentrations in the meat, the diet should contain 5% flaxseed oil.

Bioavailability of Dietary Omega-3 Fatty Acids Added to a Variety of Sausages in Healthy Individuals

A low Omega-3 Index (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes) is associated with cardiac, cerebral, and other health issues. Intake of EPA and DHA, but not of alpha-linolenic acid (ALA), increases the Omega-3 Index. We investigated bioavailability, safety, palatability and tolerability of EPA and DHA in a novel source: a variety of sausages. We screened 96 healthy volunteers, and recruited 44 with an Omega-3 Index <5%. Participants were randomly assigned to receive a variety of sausages enriched with approximately 250 mg EPA and DHA per 80 g (n = 22) daily for 8 weeks, or matching placebo sausages (n = 22). All sausages contained approximately 250 mg ALA/80 g. In the verum group, the mean Omega-3 Index increased from 4.18 ± 0.54 to 5.72 ± 0.66% (p < 0.001), while it remained unchanged in the placebo group. While ALA levels increased only in the placebo group, DPA levels increased in both groups. Inter-individual variability in the response was large. The mean increase of the Omega-3 Index per intake of EPA and DHA we observed was higher than for other sources previously studied, indicating superior bioavailability. As increasing production of EPA and DHA is difficult, improvements of bioavailability can facilitate reaching the target range for the Omega-3 Index (8-11%).

Comparison of meat quality characteristics and oxidative stability between conventional and free-range chickens

The aim of this research was to evaluate quality traits and oxidative stability of meat products from free-range (FR) and conventionally (C) raised chickens as they actually reach consumers in the Italian retail market. Free-range female and male chickens (n = 1,500 + 1,500), medium growing ISA strain, were raised under commercial conditions for 56 (1.8 kg of live weight) and 70 d (3.1 kg of live weight), respectively; C female and male birds (n = 5,000 + 5,000) were a fast growing hybrid (Ross 708) and were separately raised for 39 (1.9 kg of live weight) and 50 d (3.1 kg of live weight), respectively. A total of 96 chickens (equally divided by production system and sex) were slaughtered in 2 separate sessions to obtain the main 2 commercial categories (rotisserie and cut-up, respectively). After slaughtering, 12 carcasses of each treatment group were randomly selected and used to assess quality properties, chemical composition, and oxidation stability of breast and leg meat. The C birds had dramatic higher carcass and breast meat yield, whereas FR had higher wing and leg yields. The FR birds exhibited higher water holding capacity in both breast and leg meat. Although shear force did not differ in breast meat, legs from FR birds were tougher. Fatty acid composition of FR breast and thigh meat of both categories were characterized by a higher polyunsaturated fatty acid n-6-/n-3 ratio. In general, a low lipid oxidation level (peroxide value < 1.3 mEq O2/kg of lipid and TBA reactive substances < 0.2 mg malondialdehyde/kg of sample) was found in breast and legs, regardless of the commercial category. However, the C system significantly increased peroxide value in rotisserie thigh meat, whereas FR led to a significantly higher TBA reactive substances in breast meat. Our results demonstrated that free range can modify the properties of chicken meat and also highlighted the importance of the bird genetic background to select nutritional strategies to improve meat quality traits and oxidative stability in poultry.

Functional characterization of the chicken fatty acid elongases

The health benefits of the (n-3) PUFA, EPA, and DHA have created a demand for fish and fish oil, the main sources of these PUFA. Production animals, such as poultry, are potential alternate and sustainable sources of EPA and DHA, provided these fatty acids can be synthesized from plant-derived α-linolenic acid [ALA, 18:3(n-3)]. Because elongases are potential control points in the conversion of ALA to DHA in rats, we examined the chicken elongases, ELOVL2 and ELOVL5, which had not been characterized. ELOVL2 activity was limited to C20-22 PUFA substrates and the major product of ELOVL2 metabolism of EPA was 24:5(n-3). This indicates that ELOVL2 can sequentially elongate EPA to docosapentaenoic acid [DPA, 22:5(n-3)] and then onto 24:5(n-3). ELOVL5 selectivity was broader with elongation of C18-22 PUFA substrates. The ability of chicken ELOVL5 to efficiently synthesize 24:5(n-3) is unique compared with ELOVL5 enzymes from other species. The expression of ELOVL5 was higher than ELOVL2 in livers of broiler chickens and their expression did not change when dietary ALA was increased from 0.6 to 1.3% of dietary energy for 42 d. The expression of both genes was higher than previously seen in rats. The chicken elongase enzymes are unlike those of any species studied to date, because both ELOVL2 and ELOVL5 have the ability to efficiently elongate DPA. In addition, the relative abundance of ELOVL2 and ELOVL5 in the liver suggests that chickens may be able to metabolize more DPA through to 24:5(n-3), the precursor of DHA, compared with other species such as rats.

Increased EPA levels in serum phospholipids of humans after four weeks daily ingestion of one portion chicken fed linseed and rapeseed oil

Since the amounts of arachidonic acid (AA) and EPA in food may have implications for human health, we investigated whether a small change in chicken feed influenced the blood lipid concentration in humans ingesting the chicken. Forty-six young healthy volunteers (age 20-29) were randomly allocated into two groups in a double-blind dietary intervention trial, involving ingestion of about 160 g chicken meat per day for 4 weeks. The ingested meat was either from chickens given a feed concentrate resembling the commercial chicken feed, containing 4% soybean oil (SO), or the meat was from chickens given a feed where the soybean oil had been replaced by 2% rapeseed oil plus 2% linseed oil (RLO).Serum total cholesterol, LDL and HDL cholesterol, triacylglycerols, serum phospholipid fatty acid concentration, blood pressure, body weight and C-reactive protein were determined at baseline and post-intervention. In subjects consuming chicken meat from the RLO group there was a significantly (p < 0.001) increased concentration of EPA in serum phospholipids, and a reduced ratio between AA and EPA. The participants that had a low% of EPA + DHA in serum phospholipids (less than 4.6%), all increased their% of EPA + DHA after the four week intervention period when consuming the RLO chicken. No significant response differences in cholesterol, triacylglycerol, C-reactive protein, body weight or blood pressure were observed between the groups. This trial demonstrates that a simple change in chicken feed can have beneficial effects on amount of EPA and the AA/EPA ratio in human serum phospholipids.

The effect of feeding modified soyabean oil enriched with C18 : 4 n-3 to broilers on the deposition of n-3 fatty acids in chicken meat

Supplementing broiler diets with conventional vegetable oils has little effect on the long-chain n-3 PUFA (LC n-3 PUFA) content of the meat. The present study investigated the effect on fatty acid composition and sensory characteristics of chicken meat when broilers were fed oil extracted from soyabeans (SDASOY) that had been genetically engineered to produce C18 : 4n-3 (stearidonic acid (SDA), 240 mg/g oil). Three diets were fed to 120 birds (eight replicate pens of five birds) from 15 d to slaughter (41-50 d). Diets were identical apart from the oil added to them (45 and 50 g/kg as fed in the grower and finisher phases, respectively), which was either SDASOY, near-isogenic soya (CON) or fish oil (FISH). The LC n-3 PUFA content of the meat increased in the order CON, SDASOY and FISH. In breast meat with skin, the SDA concentration was 522, 13 and 37 (sem 14·4) mg/100 g meat for SDASOY, CON and FISH, respectively. Equivalent values for C20 : 5n-3 (EPA) were 53, 13 and 140 (sem 8·4); for C22 : 5n-3 (docosapentaenoic acid (DPA)) 65, 15 and 101 (sem 3·5); for C22 : 6n-3 (DHA) 19, 9 and 181 (sem 4·4). Leg meat (with skin) values for SDA were 861, 23 and 68 (sem 30·1); for EPA 87, 9 and 258 (sem 7·5); for DPA 95, 20 and 165 (sem 5·0); for DHA 29, 10 and 278 (sem 8·4). Aroma, taste and aftertaste of freshly cooked breast meat were not affected. Fishy aromas, tastes and aftertastes were associated with LC n-3 PUFA content of the meat, being most noticeable in the FISH leg meat (both freshly cooked and reheated) and in the reheated SDASOY leg meat.