Effects of menhaden oil and flaxseed in broiler diets on sensory quality and lipid composition of poultry meat

A review of recent studies on the enrichment of eggs and poultry meat with omega-3 polyunsaturated fatty acids: novel findings and unanswered questions

Studies from our laboratory over the past decade have yielded new information with regard to the dietary enrichment of eggs and poultry meat with omega-3 (n-3) polyunsaturated fatty acids (PUFA) but have also generated a number of unanswered questions. In this review, we summarize the novel findings from this work, identify knowledge gaps, and offer possible explanations for some perplexing observations. Specifically discussed are: 1) Why feeding laying hens and broilers an oil rich in stearidonic acid (SDA; 18:4 n-3), which theoretically bypasses the putative rate-limiting step in the hepatic n-3 PUFA biosynthetic pathway, does not enrich egg yolks and tissues with very long-chain (VLC; ≥20 C) n-3 PUFA to the same degree as obtained by feeding birds oils rich in preformed VLC n-3 PUFA; 2) Why in hens fed an SDA-rich oil, SDA fails to accumulate in egg yolk but is readily incorporated into adipose tissue; 3) How oils rich in oleic acid (OA; 18:1 n-9), when co-fed with various sources of n-3 PUFA, attenuates egg and tissue n-3 PUFA contents or rescues egg production when co-fed with a level of docosahexaenoic acid (DHA; 22:6 n-3) that causes severe hypotriglyceridemia; and 4) Why the efficiency of VLC n-3 PUFA deposition into eggs and poultry meat is inversely related to the dietary content of α-linolenic acid (ALA; 18:3 n-3), SDA, or DHA.

Dietary linseed oil affects the polyunsaturated fatty acid and transcriptome profiles in the livers and breast muscles of ducks

Linseed oil, an important source of dietary α-linolenic acid, is used to provide meat enriched in n-3 PUFA. We investigated the effects of dietary linseed oil (0, 0.5, 1, and 2%) on growth performance, meat quality, tissue fatty acid (FA), and transcriptome profiles in ducks. The result showed that dietary linseed oil had no effect on growth performance. Increasing dietary linseed oil enrichment raised n-3 PUFA and linoleic acid (LA) levels in both the liver and breast muscle, but decreased dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (ARA) levels in the liver. The liver n-3 PUFA content was negatively correlated with duck body weight. Transcriptome analysis showed that dietary linseed oil caused hepatic changes in genes (SCD, FADS1, FADS2, and ACOT6) related to the biosynthesis of unsaturated fatty acids. Besides, dietary linseed oil also affected the expression of genes related to PUFAs and downstream metabolites (such as linoleic acid, steroid hormone, progesterone, etc.) metabolic pathways in both liver and breast muscle. Key genes involved in PUFA synthesis and transport pathways were examined by RT-qPCR, and the results verified that hepatic expression levels of FADS1 and FADS2 decreased, and those of FABP4 and FABP5 increased when 2% linseed oil was added. CD36 expression level increased in breast muscle when 2% linseed oil was added. Thus, 2% dietary linseed oil supplementation produces n-3 PUFA-enriched duck products by regulating the PUFA metabolic pathways, which could be advantageous for health-conscious consumers.

Poultry Meat and Eggs as an Alternative Source of n-3 Long-Chain Polyunsaturated Fatty Acids for Human Nutrition

The beneficial effects of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) on human health are widely known. Humans are rather inefficient in synthesizing n-3 LC-PUFA; thus, these compounds should be supplemented in the diet. However, most Western human diets have unbalanced n-6/n-3 ratios resulting from eating habits and the fact that fish sources (rich in n-3 LC-PUFA) are not sufficient (worldwide deficit ~347,956 t/y) to meet the world requirements. In this context, it is necessary to find new and sustainable sources of n-3 LC-PUFA. Poultry products can provide humans n-3 LC-PUFA due to physiological characteristics and the wide consumption of meat and eggs. The present work aims to provide a general overview of the main strategies that should be adopted during rearing and postproduction to enrich and preserve n-3 LC-PUFA in poultry products. The strategies include dietary supplementation of α-Linolenic acid (ALA) or n-3 LC-PUFA, or enhancing n-3 LC-PUFA by improving the LA (Linoleic acid)/ALA ratio and antioxidant concentrations. Moreover, factors such as genotype, rearing system, transport, and cooking processes can impact the n-3 LC-PUFA in poultry products. The use of a multifactorial view in the entire production chain allows the relevant enrichment and preservation of n-3 LC-PUFA in poultry products.

Impact of both early-age acclimation and linseed dietary inclusion on fat deposition and fatty acids' meat traits in heat-stressed broiler chickens

OBJECTIVE

The purpose of this work was to investigate the combination of early-age acclimation and linseed dietary inclusion in enriching polyunsaturated fatty acids (PUFAs) in broilers' meat as a strategy to mitigate heat stress.

MATERIALS AND METHODS

A total of 400 broiler chicks were assigned to four experimental groups with four duplicates (25 animals each): C: control (basal diet), AC: early-age acclimated (basal diet), Cl: fed 5% ground linseed, and Acl: early-age acclimated and fed 5% ground linseed. The lipid and fatty acid contents of different parts (breast, thigh, liver, subcutaneous, and abdominal fat) of broilers were determined.

RESULTS

Low levels of lipids and unsaturated fatty acids have been found in the meat of acclimated broilers. Higher levels of linolenic acids were noted in Cl thigh meat compared to C (6% vs. 2.68%, respectively). The results showed that oleic and linoleic acids constitute a large part of the PUFAs of different meats. The most elevated levels of monounsaturated fatty acids were recorded in the breast meat of AcL animals. The highest content of omega-3 was recorded in the liver of AcL animals compared to that of C (14.98% vs. 7.8%, respectively).

CONCLUSION

We suggest that the combination of treatments during hot conditions has led to the reversion of the environment-affected variables to accepted values, and yields better thermoresistance, PUFA-enriched meat, and safeguard animal health which conferred to birds' better solutions to reduce fatigue and hypoxic activities, which induces a considerable consumption of oxygen.

Supplementing flaxseed oil for long periods improved carcass quality and breast fatty acid profile in Japanese quail

The efficient time for supplementing flaxseed oil to meat-type quail to produce n-3 fatty acid fortified meat has not been determined. This study was conducted to find out the effects of different periods of flaxseed oil supplementation in the Japanese quail diet on the subsequent growth performance, carcass characteristics, fatty acids profile of breast, and functional properties of the Japanese quail meat. Totally, 720 one-day-old Japanese quail were studied in a 35-day experiment using a completely randomized design. Substituting sunflower oil with flaxseed oil had no significant effect on weight gain and feed intake in Japanese quails. Supplementing flaxseed oil for the whole 35-day growth period significantly reduced abdominal fat proportion. Flaxseed oil addition to the quail diet just a week before slaughter resulted in a 4.97-fold increase in the n-3 fatty acid content of the breast muscle. Feeding flaxseed oil decreased the activity of delta-9-desaturase in quail's breast compared to sunflower oil. The greatest thrombogenic index observed in the breast meat from control while consumption of flaxseed oil significantly decreased the thrombogenic index. Supplementing flaxseed oil to quail's diet for 21 and 35 days before slaughter significantly increased breast malondialdehyde content. Feeding flaxseed oil for long periods had no significant impact on the breast meat pH while water holding capacity was decreased. The breast lightness was increased when the flaxseed oil was fed for longer periods. Generally, feeding flaxseed oil in the last week of the growth period improved the feed conversion ratio and the fatty acid profile of quail breast meat with the minimum deterioration effects on meat quality characteristics.

Omega-3 and Omega-6 Fatty Acids in Poultry Nutrition: Effect on Production Performance and Health

Omega-3 (ω-3) and omega-6 (ω-6) fatty acids are important components of cell membranes. They are essential for health and normal physiological functioning of humans. Not all fatty acids can be produced endogenously owing to the absence of certain desaturases; however, they are required in a ratio that is not naturally achieved by the standard diet of industrialized nations. Poultry products have become the primary source of long-chain polyunsaturated fatty acids (LC-PUFA), with one of the most effective solutions being to increase the accretion of PUFAs in chicken products via the adjustment of fatty acids in poultry diets. Several studies have reported the favorable effects of ω-3 PUFA on bone strength, bone mineral content and density, and semen quality. However, other studies concluded negative effects of LC-PUFA on meat quality and palatability, and acceptability by consumers. The present review discussed the practical application of ω-3 and ω-6 fatty acids in poultry diets, and studied the critical effects of these fatty acids on productive performance, blood biochemistry, immunity, carcass traits, bone traits, egg and meat quality, and semen quality in poultry. Future studies are required to determine how poultry products can be produced with higher contents of PUFAs and favorable fatty acid composition, at low cost and without negative effects on palatability and quality.

Effect of Soybean or Linseed Oil With RRR-D-α-Tocopherol or Dl-α-Tocopherol Acetate on Quality Characteristics and Fatty Acid Profile of Turkey Meat

In this study, the effect of the halved dosage of RRR-d-α-tocopherol (with respect to dl-α-to-copherol acetate) in diets containing oil rich in linoleic or α-linolenic acid (soybean or linseed oil, respectively) on the quality characteristics and fatty acid (FA) profile of turkey meat was studied. The experiment was conducted using 480 one-week-old turkey hens Big 6 line reared until the 16th week of life. The hens in Groups I and II received soybean oil added to their feed mixture, in Groups III and IV linseed oil was the source of supplementary fat. Turkeys in Groups I and III received dl-α-tocopherol acetate, whereas those in Groups II and IV RRR-d-α-tocopherol. No influence of dietary manipulation was observed on the chemical composition of turkey meat. The combined effect of the type of dietary fat and vitamin E source added to the feed was assessed using the color parameters. The addition of natural vitamin E to the feed mixture with linseed oil significantly increased the proportion of PUFA in breast muscle lipids compared with the group receiving soybean oil with this form of vitamin E. The inclusion of linseed oil increased the content of α-linolenic acid and total n-3 FA concentration in both muscles, compared with the diet that contained soybean oil. This modification of FA composition led to lower n-6/n-3 ratio in both the breast and thigh muscles regardless of the dietary vitamin E source. The use of natural form of tocopherol in diets containing linseed oil may help to improve the nutritional quality of turkey meat, especially by enhancing n-3 PUFA levels with no detrimental effect of lipid addition on the chemical composition and quality of meat.

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.

A reduced cost strategy for enriching chicken meat with omega-3 long chain polyunsaturated fatty acids using dietary flaxseed oil

1. This study aimed to determine the minimal duration required for feeding male broilers (Cobb 500) with a flaxseed oil diet while still retaining long chain omega-3 polyunsaturated fatty acid (n-3 LCPUFA) accumulation in the meat at a desirable level. 2. Three groups of broilers (60 each) were fed on a 3% flaxseed oil (high α-linolenic acid (ALA)) diet for either 6, 4 or 2 weeks prior to slaughter. During the remaining time they were maintained on a 3% macadamia oil (low ALA) diet. A fourth group (control, n = 60) was fed on a commercial diet for 6 weeks. 3. No significant difference was observed in growth performance of broilers between groups. The amounts of total n-3 and n-3 LCPUFA in breast and thigh meat were not different between broilers fed the flaxseed oil diet for 4 and 6 weeks, but they were lower (P < 0.001) in those fed the flaxseed diet for only 2 weeks. 4. These results suggest comparable levels of n-3 LCPUFA in the meat can be achieved by only feeding the flaxseed oil diet in the last 3-4 weeks of the growth period; this would result in a ≥ 9.4% reduction in the use of flaxseed oil compared to 6 weeks of feeding; thereby reducing the cost of the enrichment process.

In ovo exposure to omega-3 fatty acids does not enhance omega-3 long-chain polyunsaturated fatty acid metabolism in broiler chickens

The content of omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) in chicken meat can be boosted by feeding broilers a diet containing α-linolenic acid (ALA, from flaxseed oil), some of which is converted by hepatic enzymes to n-3 LCPUFA. However, most of the accumulated n-3 polyunsaturated fatty acid (PUFA) in meat tissues is still in the form of ALA. Despite this, the levels of chicken diets are being enhanced by the inclusion of vegetable and marine sources of omega-3 fats. This study investigated whether the capacity of chicken for n-3 LCPUFA accumulation could be enhanced or inhibited by exposure to an increased supply of ALA or n-3 LCPUFA in ovo. Breeder hens were fed either flaxseed oil (High-ALA), fish oil (high n-3 LCPUFA) or tallow- (low n-3 PUFA, Control) based diets. The newly hatched chicks in each group were fed either the High-ALA or the Control diets until harvest at 42 days' post-hatch. The n-3 PUFA content of egg yolk and day-old chick meat closely matched the n-3 PUFA composition of the maternal diet. In contrast, the n-3 PUFA composition of breast and leg meat tissues of the 42-day-old offspring closely matched the diet fed post-hatch, with no significant effect of maternal diet. Indeed, there was an inhibition of n-3 LCPUFA accumulation in meat of the broilers from the maternal Fish-Oil diet group when fed the post-hatch High-ALA diet. Therefore, this approach is not valid to elevate n-3 LCPUFA in chicken meat.

The Fatty Acid Profile and Oxidative Stability of Meat from Turkeys Fed Diets Enriched with n-3 Polyunsaturated Fatty Acids and Dried Fruit Pomaces as a Source of Polyphenols

The aim of this study was to determine the efficacy of different dietary fruit pomaces in reducing lipid oxidation in the meat of turkeys fed diets with a high content of n-3 polyunsaturated fatty acids (PUFAs). Over a period of 4 weeks before slaughter, turkeys were fed diets with the addition of 5% dried apple, blackcurrant, strawberry and seedless strawberry pomaces (groups AP, BP, SP and SSP, respectively) and 2.5% linseed oil. Pomaces differed in the content (from 5.5 in AP to 43.1 mg/g in SSP) and composition of polyphenols Proanthocyanidins were the main polyphenolic fraction in all pomaces, AP contained flavone glycosides and dihydrochalcones, BP contained anthocyanins, and SP and SSP-ellagitannins. The n-6/n-3 PUFA ratio in all diets was comparable and lower than 2:1. In comparison with groups C and AP, the percentage of n-3 PUFAs in the total fatty acid pool of white meat from the breast muscles of turkeys in groups BP, SP and SSP was significantly higher, proportionally to the higher content of α-linolenic acid in berry pomaces. The fatty acid profile of dark meat from thigh muscles, including the n-6/n-3 PUFA ratio, was similar and lower than 3:1 in all groups. Vitamin A levels in raw breast muscles were higher in group AP than in groups C and BP (P<0.05). The addition of fruit pomaces to turkey diets lowered vitamin E concentrations (P = 0.001) in raw breast muscles relative to group C. Diets supplemented with fruit pomaces significantly lowered the concentration of thiobarbituric acid reactive substances (TBARS) in raw, frozen and cooked meat. Our results indicate that the dietary application of dried fruit pomaces increases the oxidative stability of meat from turkeys fed linseed oil, and strawberry pomace exerted the most desirable effects due to its highest polyphenol content and antioxidant potential.

Effect of dietary ALA on growth rate, feed conversion ratio, mortality rate and breast meat omega-3 LCPUFA content in broiler chickens

We have previously demonstrated that feeding chickens a diet containing high levels of the n-3 PUFA α-linolenic acid (ALA) significantly increases the content of the principal omega-3 long-chain polyunsaturated fatty acids, eicosapentaenoic acid and docosahexaenoic acid, in their meat and eggs. However, the effect of the diet on production characteristics of the birds has not been assessed. This study aimed to determine the effect of feeding male and female Cobb 500 broilers (n = 3840) a high ALA diet (containing 2.5% flaxseed oil) compared with a standard commercial Control diet (containing 2.5% tallow) on growth, feed conversion ratio and mortality until 6 weeks of age. As expected the dietary flaxseed oil significantly increased breast meat levels of omega-3 polyunsaturated fatty acids (~4-fold), with most eicosapentaenoic acid and docosahexaenoic acid being deposited in the phospholipid fraction. Both male and female birds fed the high ALA diet were significantly heavier at 6 weeks of age (77 g heavier in females, 87 g heavier in males). They also had a significantly (10%) lower feed conversion ratio, and a mortality rate that was not different from the Control diet across the 6-week feeding period. These findings indicate that a high ALA diet has the potential to enrich chicken breast meat with eicosapentaenoic acid and docosahexaenoic acid without loss of growth rate or feed efficiency, or increase in fat content of breast meat.

Effects of fermentatively recovered fish waste lipids on the growth and composition of broiler meat

1. The aim of the present study was to evaluate the effects of feeding fermentatively recovered fish oil (FFO) from fish processing waste (FPW), on the performance and carcass composition of broilers. A total of 60 one-d-old VenCobb broiler chicks randomly assigned to 5 treatment groups were studied. 2. The birds were randomly assigned to treatment groups and fed with a normal commercial diet (control, T1), a diet with 2% groundnut oil (positive control, T2), a diet with 1% FFO (T3), a diet with 1.5% FFO (T4) and a diet with 2% FFO (T5). Performance and growth parameters (feed intake and body weight) and fatty acid composition of serum, liver and meat were determined. 3. The performance characteristics of broiler meat did not differ among treatments. Feeding FFO reduced total cholesterol concentration in serum, meat and liver of the FFO-fed groups (T3 to T5) as compared to both the controls (T1 and T2), but there was no significant difference in triglyceride concentration between treatments. Increased concentrations of EPA and DHA in serum, liver and meat of FFO-fed groups, as compared to both controls, were observed as the FFO concentration increased. 4. The study clearly demonstrates the value of oil recovered from FPW in addition to addressing the environmental issues related to disposal of such biological waste.

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.

Performance and Fatty Acid Composition of Adipose Tissue, Breast and Thigh in Broilers Fed Flaxseed: A Review

Interest on the enrichment of poultry meat with n-3 fatty acids has increased given its important role in human health. Flaxseed is the main sources of n-3 fatty acids, and contains between 45 to 71% of total fatty acids of the oil as α-linolenic acid. This paper reviews the plausibility of n-3 enrichment. Its focus is on the processing of flaxseed and begins by summarizing the benefits of supplementation on broiler performance. The literature on altering the FA deposition in different tissues is then reviewed, and the factors that affect the incorporation of n-3 PUFA into edible tissues of poultry are investigated. Flaxseed supplementation caused a reduction in the abdominal fat pad, and the main fatty acid deposited in the tissue is LNA. The use of fold-change analysis allowed interpreting and determining the variation of results within experiments that do not report data in similar units of measure. The fold change analysis identified three categories of desaturation response to feeding flaxseed to broilers, resulting in different values for EPA and DHA in both breast and thigh tissues: high, medium and low fold-changes. The use of flaxseed oil, whole or ground flaxseed 14 to 21 day before slaughter is recommended to poultry producers as feeding strategies to optimize n-3 enrichment, without compromising animal performance. Enriched DHA deposition could be accomplished feeding whole flaxseed.

Dietary alpha-linolenic acid enhances omega-3 long chain polyunsaturated fatty acid levels in chicken tissues

The effects of enriching broiler chicken diets with a vegetable source of n-3 fat in the form of alpha-linolenic acid (ALA, 18:3n-3) on the accumulation of n-3 long chain polyunsaturated fatty acids (LCPUFA) in chicken meat were investigated. Sixty unsexed one-day-old broiler chickens (Cobb 500) were randomly allocated to one of six diets (n=10 birds/diet) for 4 weeks. The ALA levels varied from 1 to 8% energy (%en) while the level of the n-6 fatty acid linoleic acid (LA, 18:2n-6) was held to less than 5%en in all diets. At harvest (day 28) the levels of n-3 LCPUFA including eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) in breast and thigh meat increased in a curvilinear manner as dietary ALA increased, reaching 4- to 9-fold above the levels seen in control birds. In contrast, arachidonic acid (AA) was reduced in response to increasing dietary ALA.

Dietary combination effects of conjugated linoleic acid and flaxseed or fish oil on the concentration of linoleic and arachidonic acid in poultry meat

This study was conducted to determine the effects of the combination of dietary conjugated linoleic acid (CLA) and n-3 fatty acids on the linoleic acid (C18:2n-6) and arachidonic acid (C20:4n-6) concentrations of broiler chicken breast and thigh muscles. One hundred and twenty broilers were raised to 6 wk of age. All chicks were fed a basal corn-soybean meal diet containing 5 different fat sources at an inclusion level of 2% total fat: 1) CLA, 2) flaxseed oil, 3) menhaden fish oil, 4) CLA and flaxseed oil, and 5) CLA and menhaden fish oil. Eight broilers from each treatment were processed at 4 and 6 wk of age. Breast and thigh muscle samples were collected and analyzed for total fat content and fatty acid composition. The results showed that broilers from the CLA and fish oil treatment had lower arachidonic acid concentrations in both breast and thigh muscles than those fed the flaxseed oil diet or the CLA and flaxseed oil diet (P < 0.05). The arachidonic acid concentration and n-6:n-3 ratio of breast and thigh samples from the menhaden fish oil diet were similar to those of the CLA and fish oil diet (P > 0.05), but the inclusion of linoleic acid into chicken thigh muscles of broilers fed the CLA and menhaden fish oil diet improved significantly when compared with that of the diet containing menhaden fish oil only. Thus, the combination of CLA and menhaden fish oil is recommended to reduce the concentrations of linoleic and arachidonic acids in broiler chicken breast and thigh muscles.

Dietary strategies to improve nutritional value, oxidative stability, and sensory properties of poultry products

Consumers demand both safer and more nutritious food products exempt of non-natural origin preservatives or other food additives. In this frame, products with lower fat content and/or a higher ratio in unsaturated fatty acids, especially n-3 fatty acids, are desired because these lipids can help prevent the development of cardiovascular and inflammatory pathologies. The intake of meat products is of interest because they are an excellent source of vitamins and minerals. In addition, the shelf-life of meat products can be extended by the presence of natural antioxidants coming from different sources such as plant extracts. Therefore, different strategies have been studied to improve the nutritional value, oxidative stability, and sensory characteristics of meat products and eggs through different mineral and natural dietary supplements. In comparison to other strategies, dietary supplements present the advantage that first the living animals may efficiently distribute the compounds throughout the tissues and second, the dietary supplementation is safer because the resulting enriched meat products and eggs ensure tolerable amounts in humans. Poultry meats and eggs are widely consumed and their fatty acid profile and tocopherol content can be easily modified through different dietary strategies thus being excellent models to improve their nutritional value and oxidative stability.

Effects of vitamin E and fish oil inclusion in broiler diets on meat fatty acid composition and on the flavour of a composite sample of breast meat

BACKGROUND

Enriching poultry meat with long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) can increase low population intakes of LC n-3 PUFA, but fishy taints can spoil reheated meat. This experiment determined the effect of different amounts of LC n-3 PUFA and vitamin E in the broiler diet on the fatty acid composition and sensory characteristics of the breast meat. Ross 308 broilers (120) were randomly allocated to one of five treatments from 21 to 42 days of age. Diets contained (g kg(-1)) 0, 9 or 18 LC n-3 PUFA (0LC, 9LC, 18LC), and 100, 150 or 200 mg LD-alpha-tocopherol acetate kg(-1) (E). The five diets were 0LC100E, 9LC100E, 18LC100E, 18LC150E, 18LC200E, with four pens per diet, except 18LC100E (eight pens). Breast meat was analysed for fatty acids (uncooked) and sensory analysis by R-index (reheated).

RESULTS

LC n-3 PUFA content (mg kg(-1) meat) was 514 (0LC100E) and 2236 (9LC and 18LC). Compared with 0LC100E, meat from 18LC100E and 18LC150E tasted significantly different, while 23% of panellists detected fishy taints in 9LC100E and 18LC200E.

CONCLUSION

Chicken meat can be enriched with nutritionally meaningful amounts of LC n-3 PUFA, but > 100 mg dl-alpha-tocopherol acetate kg(-1) broiler diet is needed to protect reheated meat from oxidative deterioration.

Removal of trimethylamine by adsorption over zeolite catalysts and deodorization of fish oil

Trimethylamine (TMA) is the main agent for the odor often associated with fouling fish, some infections, and bad breath. This study focused on the adsorption of TMA over various microporous zeolites for application in the low-temperature deodorization of fishy odor from raw fish oil. The faujasite (Si/Al=3) zeolite exhibited the high adsorption ability, which, in combination with its wide surface area and pore volume, may have induced the high adsorption ability. The H-mordenite (Si/Al=10) zeolite exhibited a large TMA adsorption. It was considered to have generated more attractive adsorption with TMA ions, because TMA interacted briskly with cations of acid sites on the zeolites. The fishy odor of raw fish oil was considerably reduced by low-temperature adsorption on the zeolites. The surface area of the zeolites retained most of the TMA adsorption ability, and their acid strength further enhanced the adsorption ability.

Postgraduate Symposium Long-chainn-3 PUFA: intakes in the UK and the potential of a chicken meat prototype to increase them

With the wide acceptance of the long-chain (LC)n-3 PUFA EPA and DHA as important nutrients playing a role in the amelioration of certain diseases, efforts to understand factors affecting intakes of these fatty acids along with potential strategies to increase them are vital. Widespread aversion to oil-rich fish, the richest natural source of EPA and DHA, highlights both the highly suboptimal current intakes in males and females across all age-groups and the critical need for an alternative supply of EPA and DHA. Poultry meat is a popular and versatile food eaten in large quantities relative to other meats and is open to increased LCn-3 PUFA content through manipulation of the chicken's diet to modify fatty acid deposition and therefore lipid composition of the edible tissues. It is therefore seen as a favourable prototype food for increasing human dietary supply of LCn-3 PUFA. Enrichment of chicken breast and leg tissue is well established using fish oil or fishmeal, but concerns about sustainability have led to recent consideration of algal biomass as an alternative source of LCn-3 PUFA. Further advances have also been made in the quality of the resulting meat, including achieving acceptable flavour and storage properties as well as understanding the impact of cooking on the retention of fatty acids. Based on these considerations it may be concluded that EPA- and DHA-enriched poultry meat has a very positive potential future in the food chain.

Effect of dietary omega6/omega3 on growth performance, carcass traits, meat quality and fatty acid profiles of Beijing-you chicken

The effects of varying the omega6 to omega3 fatty acid ratio (omega6/omega3) of diets on growth performance, carcass traits, meat quality and fatty acid composition of breast muscle were investigated in Beijing-you chickens grown to 92 days. A total of 360 one-day-old female BJY chickens were fed diets containing 0%, 0.12%, 0.42%, 1.00% or 1.97% linseed oil replacing equal weights of maize oil to make dietary omega6/omega3 to be approximately 30:1, 20:1, 10:1, 5:1 and 2.5:1. Subcutaneous fat thickness and intramuscular fat content increased significantly in birds fed up to 10:1 omega6/omega3. a* values (redness of meat, dimension of the CIELAB-system) progressively increased as the diets contained increasing omega3 content, up to the 10:1 omega6/omega3.The changes in b* (yellowness of meat, dimensions of the CIELAB-system) were also significant but the pattern was almost the reverse of changes in a*. Shear force increased significantly as dietary omega6/omega3 was reduced from 30:1 to 5:1. Decreasing the dietary omega6/omega3 clearly decreased the content in breast muscle of C20:1 and C22:1, but increased that of C24:1. C20:4, C20:5 and C22:5, increased significantly by decreasing the dietary omega6/omega3, and the birds fed the 10:1 diet had higher contents of C22:6 than other treatments. This study has clearly demonstrated that decreasing the dietary omega6/omega3, increases the deposition of desirable omega3 and omega6 long chain PUFA in the edible tissue, thereby achieving nutritionally enriched meat.

Study on the raw fish oil purification from PCDD/F and dl-PCB-industrial tests

The results of tests for the purification of fish oils with activated carbon for industrial use are presented. The optimum parameters for the process of purification (granulation of the activated carbon, its dosage, the oil temperature, and the duration of mixing the oil with activated carbon) were previously established for the laboratory scale. The optimization of the process consisted of selecting purification parameters that would allow for maximum reduction of the toxic polychlorinated dibenzo-para-dioxins and polychlorinated dibenzofurans (PCDD/Fs) content, while retaining the favorable high fatty acid content [C20:5 n-3, eicosapentaenoic acid (EPA) and C22:6 n-3, docosahexaenoic acid (DHA)]. The use of that optimum parameters in industrial conditions confirmed the satisfactory results obtained in laboratory tests. Five types of oil derived from various Baltic fish were purified. Reduction in the PCDD/Fs content was 77.0-93.6% on average, whereas in the dioxin-like polychlorinated biphenyls (dl-PCBs)-it was 42.7-50.5% on average, with insignificant changes in the total amount of EPA and DHA content. Furthermore, a significant reduction in the content of arsenic was noted (by about 62% on average), with insignificant changes in the content of organochlorine pesticides (OCPs), and marker polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), cadmium, lead, and mercury. Purification provided fish oil having standardized parameters that allow for its use as feed additives, whilst retaining its favorable fatty acid content.

Effect of dietary selenium and omega-3 fatty acids on muscle composition and quality in broilers

Background

Human health may be improved if dietary intakes of selenium and omega-3 fatty acids are increased. Consumption of broiler meat is increasing, and the meat content of selenium and omega-3 fatty acids are affected by the composition of broiler feed. A two-way analyses of variance was used to study the effect of feed containing omega-3 rich plant oils and selenium enriched yeast on broiler meat composition, antioxidation- and sensory parameters. Four different wheat-based dietary treatments supplemented with 5% rapeseed oil or 4% rapeseed oil plus 1% linseed oil, and either 0.50 mg selenium or 0.84 mg selenium (organic form) per kg diet was fed to newly hatched broilers for 22 days.

Results

The different dietary treatments gave distinct different concentrations of selenium and fatty acids in thigh muscle; one percent linseed oil in the diet increased the concentration of the omega-3 fatty acids 18:3, 20:5 and 22:5, and 0.84 mg selenium per kg diet gave muscle selenium concentration at the same level as is in fish muscle (0.39 mg/kg muscle). The high selenium intake also resulted in increased concentration of the long-chain omega-3 fatty acids EPA (20:5), DPA (22:5) and DHA (22:6), thus it may be speculated if high dietary selenium might have a role in increasing the concentration of EPA, DPA and DHA in tissues after intake of plant oils contning omega-3 fatty acids.

Conclusion

Moderate modifications of broiler feed may give a healthier broiler meat, having increased content of selenium and omega-3 fatty acids. High intakes of selenium (organic form) may increase the concentration of very long-chain omega-3 fatty acids in muscle.

Effect of Genotype on Slaughtering Performance and Meat Physical and Sensory Characteristics of Organic Laying Hens

Slaughtering yields and some meat physical and sensorial parameters of laying hens reared under organic system production were studied. The hens belonged to both Italian dual-purpose breeds [Ermellinata di Rovigo (ER; brown eggshell) and Robusta Maculata (RM; brown eggshell)] as well as hybrid genotypes [Hy Line White 36 (white eggshell) and Hy Line Brown (brown eggshell)]. The birds were reared under organic farming system production from 24 to 44 wk of age, when they were slaughtered. They were reared throughout summer and autumn, and the temperature ranged from about 28 to 3 degrees C. Local breeds presented higher (P < 0.01) live BW and dressing percentage compared with hybrids. The RM and ER carcasses had (P < 0.01) the highest breast and leg (thigh and drumstick) percentage, respectively. The muscle-bone ratio of the Hy Line White 36 drumstick was lower (P < 0.05) than the RM ratio, whereas the other groups were intermediate. The ER breast presented the highest (P < 0.01) lightness value and the lowest (P < 0.01) final pH value compared with the other 3 groups. The breast meat significantly differed according to genotype for almost all the studied sensorial parameters (adhesivity, fibrousness, chewiness, solubility, juiciness, tenderness, shear resistance), with the exception of aroma and odor intensity. In the thigh, genotype significantly affected aroma, adhesivity, fibrousness, solubility, tenderness, and shear resistance.

Effect of species and genotype on the efficiency of enrichment of poultry meat with n-3 polyunsaturated fatty acids

The effect of poultry species (broiler or turkey) and genotype (Wrolstad or BUT T8 turkeys and Ross 308 or Cobb 500 broilers) on the efficiency with which dietary long-chain n-3 PUFA were incorporated into poultry meat was determined. Broilers and turkeys of both genotypes were fed one of six diets varying in FA composition (two replicates per genotype x diet interaction). Diets contained 50 g/kg added oil, which was either blended vegetable oil (control), or partially replaced with linseed oil (20 or 40 g/kg diet), fish oil (20 or 40 g/kg diet), or a mixture of the two (20 g linseed oil and 20 g fish oil/kg diet). Feeds and samples of skinless breast and thigh meat were analyzed for FA. Wrolstad dark meat was slightly more responsive than BUT T8 (P = 0.046) to increased dietary 18:3 concentrations (slopes of 0.570 and 0.465, respectively). The Ross 308 was also slightly more responsive than the Cobb 500 (P = 0.002) in this parameter (slopes of 0.557 and 0.449). There were no other significant differences between the genotypes. There was some evidence (based on the estimates of the slopes and their associated standard errors) that white turkey meat was more responsive than white chicken meat to 20:5 (slopes of 0.504 and 0.289 for turkeys and broilers, respectively). There was no relationship between dietary 18:3 n-3 content and meat 20:5 and 22:6 contents. If birds do convert 18:3 to higher FA, these acids are not then deposited in the edible tissues.

n-3 fatty acid enrichment of edible tissue of poultry: a review

There is clear evidence of the nutritional benefits of consuming long-chain n-3 PUFA, which are found predominantly in oily fish. However, oily fish consumption, particularly in the United Kingdom, is declining, as is the consumption of all meats with the exception of poultry, which has increased in consumption by 73% in the last 30 yr. This pattern, if less marked, is reflected throughout Europe, and therefore one means of increasing long-chain n-3 PUFA consumption would be to increase the long-chain n-3 PUFA content in the edible tissues of poultry. This review considers the feasibility of doing this, concentrating particularly on chickens and turkeys. It begins by summarizing the benefits to human health of consuming greater quantities of n-3 FA and the sources of n-3 PUFA in the human diet. The literature on altering the FA composition of poultry meat is then reviewed, and the factors affecting the incorporation of n-3 PUFA into edible tissues of poultry are investigated. The concentration of alpha-linolenic acid (ALA) in the edible tissues of poultry is readily increased by increasing the concentration of ALA in the birds' diet (particularly meat with skin, and dark meat to a greater extent than white meat). The concentration of EPA in both white and dark meat is also increased when the birds' diet is supplemented with EPA, although supplementing the diet with the precursor (ALA) does not result in a noticeable increase in EPA content in the edible tissues. Although supplementing the birds' diets with relatively high concentrations of DHA does result in an increased concentration of DHA in the tissues, the relationship between dietary and tissue concentrations of DHA is much weaker than that observed with ALA and EPA. The impact that altering the FA composition of edible poultry tissue may have on the organoleptic and storage qualities of poultry products is also considered.

Effect of dietary fat sources and zinc and selenium supplements on the composition and consumer acceptability of chicken meat

A factorial design was used to study the effect of changes in broiler feed on the composition and consumer acceptability of chicken meat. One week before slaughter, 1.25% dietary fish oil was removed from the feed and replaced by other fat sources (animal fat or linseed oil) or we continued with fish oil, and diets were supplemented with Zn (0, 300, or 600 mg/kg), and Se (0 or 1.2 mg/kg as sodium selenite or 0.2 mg/kg as Se-enriched yeast). The changes in dietary fat led to distinct fatty acid compositions of mixed raw dark and white chicken meat with skin. The fish oil diet produced meat with the highest eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) content, whereas the linseed oil diet led to meat with the highest content in total n-3 polyunsaturated acids (PUFA), especially linolenic acid. However, meat from animals on the animal fat diet was still rich in very long-chain n-3 PUFA. Se content was affected by Se and Zn supplements. Se content increased with Zn supplementation. However, only Se from the organic source led to a significant increase in this mineral in meat compared with the control. Consumer acceptability scores and TBA values of cooked dark chicken meat after 74 d or after 18 mo of frozen storage were not affected by any of the dietary factors studied.

Effect of dietary fish oil, alpha-tocopheryl acetate, and zinc supplementation on the composition and consumer acceptability of chicken meat

A factorial design was used to study the effect of dietary fish oil (1.25% and 2.5%), all-rac-alpha-tocopheryl acetate (70 and 140 mg/kg), and Zn supplementation (0 and 200 mg/kg) on the composition and consumer acceptability of chicken meat stored at -20 degrees C for 5 mo. Supplementation of the diet with all-rac-alpha-tocopheryl acetate increased the alpha-tocopherol content in meat. The fatty acid composition of the meat was affected only by the amount of fish oil. Diets supplied with 2.5% fish oil produced meat with an eicosapentaenoic and docosahexaenoic acid content double that of diets supplied with 1.25% fish oil. Zn supplementation did not affect the content of this mineral in the meat. Moreover, the consumer acceptability of meat samples showed no significant differences between dietary treatments after 5 mo of storage at -20 degrees C or with respect to a freshly cooked commercial sample used as a blind control.

Fatty Acid Content in Chicken Thigh and Breast as Affected by Dietary Polyunsaturation Level

One hundred ninety-two female broiler chickens were randomly distributed into 16 experimental treatments as a result of the combination of 4 levels of dietary polyunsaturated fatty acids (PUFA) (15, 34, 45, and 61 g/kg) and 4 levels of supplementation with alphatocopheryl acetate (alpha-TA) (0, 100, 200, and 400 mg/kg), to determine the modification of the amount and type of fatty acids (FA) deposited in raw and cooked chicken tissues. At 44 d, quantified FA of thighs and breasts were not affected by dietary supplementation with alpha-TA. Total FA content of breast was less than 15% of the total FA content of thigh. However, increasing the PUFA content of the diet by 46 g, from 15 to 61 g/kg, decreased total FA of thigh 17%, but did not affect FA content in breast meat. Monounsaturated fatty acid (MUFA) and saturated fatty acid (SFA) content of thigh (y) decreased linearly as the inclusion of dietary PUFA (x) increased (MUFA: y = 89.34 - 0.92x, R2 = 0.70; SFA: y = 53.81 - 0.43x, R2 = 0.57), whereas the relationship between PUFA content of feed (x) and thighs (y) was exponential (y = 92.03 92.03e(-00155x), R2 = 0.75). A similar response was observed in breast, with less variation and more incorporation of PUFA than thigh. Cooking of thigh meat led to a reduction in total FA content that affected SFA, MUFA, and PUFA in a similar proportion.

Flaxseed increased alpha-linolenic and eicosapentaenoic acid and decreased arachidonic acid in serum and tissues of rat dams and offspring

The effects of dietary flaxseed (FS), and defatted flaxseed meal (FLM) on serum and tissue fatty acid profiles were investigated. Pregnant Sprague-Dawley rats were fed AIN-93 based diets balanced in calories, fat, nitrogen, and fiber. Diets contained 0, 20%, 40% FS or 13% or 26% FLM by weight. The control, FS and FLM diets differed in linoleic acid to alpha-linolenic acid (ALA) fatty acid ratio. These diets were fed continuously during gestation, suckling period and 8 weeks post-weaning (F(1)). FS fatty acids were bioavailable and metabolized by pregnant and F(1) rats. ALA and eicosapentaenoic acid increased; linoleic and arachidonic acid decreased; and docosahexaeonic acid was unchanged in serum, 'gastric milk' and liver of FS and FLM-fed pregnant and F(1) rats. FS more than FLM, changed fatty acids profiles, but FLM and 40% FS significantly reduced serum cholesterol. Dietary 40% FS may have increased oxidative stress as evidenced by a reduction in liver vitamin E.

Impact of high flaxseed diet on mitogen-induced proliferation, IL-2 production, cell subsets and fatty acid composition of spleen cells from pregnant and F1 generation Sprague-Dawley rats

Flaxseed (FS) being rich in alpha-linolenic acid may alter the immune parameters. Therefore, we assessed the impact of FS and defatted flaxseed meal (FLM) on fatty acid composition, cell subsets, proliferation and IL-2 production by splenic lymphocytes. Pregnant female Sprague-Dawley rats were fed diets containing 0% FS and FLM, 20 or 40% FS, 13 or 26% FLM during gestation or gestation, lactation and 8 week post-weaning period. FS and FLM resulted in up to 8.3 fold and 4.6 fold increase in splenic ALA among pregnant rats, 4.5 fold and 1.2 fold increase in splenic ALA among F(1) generation rats. Splenic linoleic acid (LA) and arachidonic acid (AA) were 18 and 40% lower in 40% FS fed pregnant rats, and AA was 15% lower in all the other groups. Among F(1) rats, splenic LA and AA were 16 and 48% lower in 40% FS group, and AA was 18% lower in 20% FS and 26% FLM groups. Concanavalin A and phytohemagglutinin mediated proliferation of spleen cells were 60 and 52% lower in 40% FS fed pregnant and F(1) generation rats, respectively. No significant changes were observed in the cell subsets or IL-2 production by splenic cells from different groups.