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

Edible Offal as a Valuable Source of Nutrients in the Diet-A Review

The global increase in demand for meat leads to substantial quantities of by-products, including edible offal from both wild and domesticated animals raised for diversified consumption products within an agricultural framework. Information on the nutritional value of offal is scattered and limited. This review aims to synthesize scientific publications on the potential of offal as a source of nutrients and bioactive substances in human diets. The literature review included publications available in ISI Web of Science and Google Scholar published between 2014 and 2024. Findings indicate that edible offal is characterized by a nutrient concentration often surpassing that found in skeletal muscle. This review discusses the yield of edible offal and explores factors influencing human consumption. Selected factors affecting the nutritional value of offal of various animals and the importance of individual nutrients in ensuring the proper functioning of the human body were analyzed. The optimal use of offal in processing and catering can significantly benefit aspects of human life, including diet quality, food security, and conservation of natural resources.

Direct Comparison of 18 Carbon n-3 and n-6 Fatty Acids at Equal Levels in an Oil Blend on Tissue Enrichment of Long-Chain Polyunsaturated Fatty Acid in Broiler Chickens

BACKGROUND

Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) are of interest because of their health effects. However, most experiments use natural oils and are confounded by PUFA concentrations and other fatty acids (FAs) that impact biosynthesis of the very long-chain derivatives (VLC).

OBJECTIVES

To directly compare the effect of 18 C n-3 or n-6 FA fed at similar rates on their elongation and desaturation to VLC PUFA and their incorporation into tissues.

METHODS

Oil blends that substituted ∼23% points of stearidonic acid (SDA) with alpha-linolenic acid (ALA), gamma-linolenic acid (GLA), or linoleic acid (LA) while minimizing differences in other FA were prepared. COBB500 broilers were fed the oil blends at 1.25% of the diet from day 14-35 age.

RESULTS

There was greater enrichment of VLC PUFA in breast, thigh, liver, and plasma when diets were supplemented with high-SDA and high-GLA oil blends than high-ALA and high-LA oil blends. The efficiency of VLCn-3 PUFA synthesis from SDA and ALA was lower than the efficiency of VLCn-6 PUFA synthesis from GLA and LA, suggesting that the elongation and desaturation enzymes more efficiently utilized n-6 substrates. The efficiency of biotransformation of SDA to VLCn-3 PUFA was greater than that of high-ALA, and synthesis of VLCn-6 PUFA from GLA was higher than that of high-LA in breast, thigh, liver, and plasma. There were minimal effects on tissue-saturated and monounsaturated FA.

CONCLUSIONS

The high-SDA and high-GLA oil blends efficiently enriched tissues with their VLC-PUFA more than high-ALA and high-LA treatments.

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.

Effects of linseed oil supplementation duration on fatty acid profile and fatty acid metabolism-related genes in the muscles of Chinese crested white ducks

Meat rich in polyunsaturated fatty acids is considered beneficial to health. Supplementing the diet with linseed oil promotes the deposition of polyunsaturated fatty acids (PUFAs) in poultry, a conclusion that has been confirmed multiple times in chicken meat. However, fewer studies have focused on the effects of dietary fatty acids on duck meat. Therefore, this study aims to evaluate the effects of the feeding time of a linseed oil diet on duck meat performance and gene expression, including meat quality performance, plasma biochemical indicators, fatty acid profile, and gene expression. For this study, we selected 168 Chinese crested ducks at 28 days old and divided them into three groups, with 56 birds in each group. The linseed oil content in the different treatment groups was as follows: the control group (0% flaxseed oil), the 14d group (2% linseed oil), and the 28d group (2% linseed oil). Ducks in the two experimental groups were fed a linseed oil diet for 28 and 14 days at 28 and 42 days of age, respectively. The results showed that linseed oil had no negative effect on duck performance (slaughter rate, breast muscle weight, and leg muscle weight) or meat quality performance (pH, meat color, drip loss, and shear force) (P > 0.05). The addition of linseed oil in the diet increased plasma total cholesterol and high-density lipoprotein cholesterol levels (P < 0.05), while decreasing triglyceride content (P < 0.05). Furthermore, the supplementation of linseed oil for four weeks affected the composition of muscle fatty acids. Specifically, levels of α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were increased (P < 0.05), while eicosatetraenoic acid content was negatively correlated with flaxseed oil intake (P < 0.05). qRT-PCR analysis further revealed that the expression of FATP1, FABP5, and ELOVL5 genes in the breast muscle, as well as FABP3 and FADS2 genes in the thigh muscle, increased after four weeks of linseed oil supplementation (P < 0.05). However, after two weeks of feeding, CPT1A gene expression inhibited fatty acid deposition, suggesting an increase in fatty acid oxidation (P < 0.05). Overall, the four-week feeding time may be a key factor in promoting the deposition of n-3 PUFAs in duck meat. However, the limitation of this study is that it remains unknown whether longer supplementation time will continue to affect the deposition of n-3 PUFAs. Further experiments are needed to explain how prolonged feeding of linseed oil will affect the meat quality traits and fatty acid profile of duck meat.

FTIR-PCA Approach on Raw and Thermally Processed Chicken Lipids Stabilized by Nano-Encapsulation in β-Cyclodextrin

This study evaluated similarities/dissimilarities of raw and processed chicken breast and thigh lipids that were complexed by β-cyclodextrin, using a combined FTIR-PCA technique. Lipid fractions were analyzed as non-complexed and β-cyclodextrin-complexed samples via thermogravimetry, differential scanning calorimetry and ATR-FTIR. The lipid complexation reduced the water content to 7.67-8.33%, in comparison with the β-cyclodextrin hydrate (~14%). The stabilities of the complexes and β-cyclodextrin were almost the same. ATR-FTIR analysis revealed the presence of important bands that corresponded to the C=O groups (1743-1744 cm^-1) in both the non-complexed and nano-encapsulated lipids. Furthermore, the bands that corresponded to the vibrations of double bonds corresponding to the natural/degraded (cis/trans) fatty acids in lipids appeared at 3008-3011 and 938-946 cm^-1, respectively. The main FTIR bands that were involved in the discrimination of raw and processed chicken lipids, and of non-complexed and complexed lipids, were evaluated with PCA. The shifting of specific FTIR band wavenumbers had the highest influence, especially vibrations of the α(1→4) glucosidic bond in β-cyclodextrin for PC₁, and CH_2/3 groups from lipids for PC₂. This first approach on β-cyclodextrin nano-encapsulation of chicken lipids revealed the possibility to stabilize poultry fatty components for further applications in various ingredients for the food industry.

Feeding laying hens docosa hexaenoic acid-rich microalgae oil at 40 g/kg diet causes hypotriglyceridemia, depresses egg production, and attenuates expression of key genes affecting hepatic triglyceride synthesis and secretion, but is rescued by dietary co-supplementation of high-oleic sunflower oil

The primary goal of this study was to investigate the effect of feeding White Leghorn hens graded levels of a docosahexaenoic acid (DHA)-rich microalgae oil (MAO) on productive performance and enrichment of eggs with very long-chain (VLC) omega-3 (n-3) polyunsaturated fatty acids (PUFA). Forty-nine-week-old hens (8 per diet) were fed the following diets for 28 d: 1) A corn-soybean meal-based diet with no supplemental oil (CON); 2) CON + 10 g/kg MAO; 3) CON + 20 g/kg MAO; 4) CON + 30 g/kg MAO; 5) CON + 40 g/kg MAO; 6) CON + 40 g/kg MAO + 20 g/kg high-oleic sunflower oil (HOSO); and 7) CON + 40 g/kg MAO + 40 g/kg HOSO. Diets 6 and 7 were included because we previously reported that co-feeding high-oleic acid oils with n-3 PUFA-containing oils attenuated egg yolk n-3 PUFA contents vs. feeding hens the n-3 oils alone. All data were collected on an individual hen basis. Egg VLC n-3 PUFA enrichment plateaued, in terms of statistical significance, at the 30 g/kg MAO level (266 mg/yolk). Hens fed 40 g/kg MAO had greatly attenuated measures of hen performance, marked liver enlargement, an altered ovarian follicle hierarchy, greatly lowered circulating triglyceride levels, and depressed hepatic expression of key genes involved in triglyceride synthesis and secretion. As compared to hens fed 40 g/kg MAO alone, feeding hens 40 g/kg MAO co-supplemented with HOSO (Diets 6 and 7) restored egg production, ovarian morphology, and all other measures of hen productive performance to CON levels, elevated plasma triglyceride levels, prevented liver enlargement, and increased the hepatic expression of key genes involved in triglyceride synthesis and secretion. In conclusion, MAO can greatly enrich hens' eggs with VLC n-3 PUFA, but its recommended dietary inclusion should not exceed 20 g/kg. This would allow for near-maximal yolk VLC n-3 PUFA enrichment without impairing hen productive performance, altering the ovarian follicle hierarchy or, based on the work of others, presumably imparting off-flavors in the egg.

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.

Impact of Dietary Lavender Essential Oil on the Growth and Fatty Acid Profile of Breast Muscles, Antioxidant Activity, and Inflammatory Responses in Broiler Chickens

This study aimed to investigate the impact of dietary addition of lavender essential oil (Lavandula angustifolia L.) (LEO) on the growth performance, tissue histoarchitecture, and fatty acid profile in breast muscles, as well as blood biochemistry and immune expression of pro-inflammatory cytokines of broiler chickens. A total of 200 three-day-old broiler chickens (average body weight 101.3 ± 0.24 g) were assigned to a completely randomized design consisting of four dietary treatments (n = 50 per treatment, each replicate consisting of 10 birds) that included lavender essential oil at concentrations of 0 (control group), 200, 400, and 600 mg Kg−1 diet. The experiment lasted for 35 days. The results revealed that supplementation of lavender essential oil at 200, 400, or 600 mg/kg in broiler diets had no effect (p > 0.05) on the growth performance throughout the experimental periods (3−10, 11−23, and 24−35 days of age). According to the broken line regression model, the optimal level for dietary LEO addition was the 460 mg kg−1 diet based on the total body weight gain and feed conversion ratio results. The diets supplemented with lavender essential oil had no effect (p > 0.05) on the percentages of carcass yield or internal organs. Dietary addition of LEO significantly increased the percentages of omega-3 polyunsaturated fatty acids PUFA (n-3), omega-6 polyunsaturated fatty acids (n-6), and the n-3/n-6 ratio (p < 0.05) in the breast muscles of chickens in a level-dependent manner. The blood concentration of alanine aminotransferase was significantly increased in lavender essential oil at 600 mg kg−1 compared with other treatments. The dietary addition of LEO at 200, 400, and 600 mg kg−1 significantly reduced the malondialdehyde level. Still, they significantly increased the serum enzyme activities of total antioxidant capacity, catalase, superoxide dismutase, and the pro-inflammatory cytokine (interleukine-1 beta and interferon γ) compared with the unsupplemented group. The LEO-supplemented groups showed normal liver histomorphology as in the control group. However, the immunoexpression of the pro-inflammatory cytokine transforming growth factor β was significantly increased by increasing the level of LEO. It can be concluded that lavender essential oil can be included in broiler chicken diets up to 460 mg kg −1 with no positive effect on the bird’s growth. It can improve the antioxidant capacity and enrich the breast muscles with PUFA. An increased level of supplementation (600 mg kg−1) increased the inflammatory responses in broiler chickens.

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.

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.

Comparison of Ahiflower oil containing stearidonic acid to a high-alpha-linolenic acid flaxseed oil at two levels on tissue omega-3 enrichment in broilers

Enrichment of broiler meat with very long-chain omega-3 fatty acids (VLCn-3 FA) is of interest because of their beneficial effects on human health. The ability of Ahiflower® (AHI) oil (Buglossoides arvensis), which naturally contains stearidonic acid (SDA), and a high-alpha-linolenic acid (ALA) flaxseed (FLAX) oil to enrich VLCn-3 FA contents in broilers tissues was investigated. Fifty-five Cobb 500 chicks were fed from days 12 to 35 of life either a control (CON) diet that contained 27.9 g/kg soybean oil or AHI or FLAX oils, each individually at 7.5 or 22.5 g/kg of the diet in substitution for soybean oil (all on an as fed basis). Total VLCn-3 FA contents were greater in breast, thigh, liver, adipose tissue, and plasma of all n-3 treatments compared to CON, with the greatest increase observed at the highest level of AHI and FLAX oils (p < 0.001). AHI oil at 7.5 g/kg promoted the most efficient synthesis and deposition of VLCn-3 in broiler tissues measured as deposition of VLCn-3 FA in tissues relative to intake of n3 FA. In conclusion, both ALA and SDA oils increased VLCn-3 FA deposition in tissues, but there were diminishing returns when increasing dietary levels of the oils.

Fighting Fat With Fat: n-3 Polyunsaturated Fatty Acids and Adipose Deposition in Broiler Chickens

Modern broiler chickens are incredibly efficient, but they accumulate more adipose tissue than is physiologically necessary due to inadvertent consequences of selection for rapid growth. Accumulation of excess adipose tissue wastes feed in birds raised for market, and it compromises well-being in broiler-breeders. Studies driven by the obesity epidemic in humans demonstrate that the fatty acid profile of the diet influences adipose tissue growth and metabolism in ways that can be manipulated to reduce fat accretion. Omega-3 polyunsaturated fatty acids (n-3 PUFA) can inhibit adipocyte differentiation, induce fatty acid oxidation, and enhance energy expenditure, all of which can counteract the accretion of excess adipose tissue. This mini-review summarizes efforts to counteract the tendency for fat accretion in broilers by enriching the diet in n-3 PUFA.

Supplemental dietary oils rich in oleic acid or linoleic acid attenuate egg yolk and tissue n-3 polyunsaturated fatty acid contents in laying hens co-fed oils enriched in either stearidonic acid or α-linolenic acid

We previously reported that when laying hens were fed diets supplemented with oils enriched in α-linolenic acid (ALA) and oleic acid (OA), the deposition of n-3 PUFA in egg yolk was attenuated as compared to feeding hens a diet supplemented with the ALA-rich oil alone. The present work extends those findings to another n-3 PUFA-rich oil (stearidonic acid [SDA]-enriched soybean oil) and two other high-OA oils, suggesting that the effect is not plant oil-specific. Feeding hens a supplemental linoleic acid (LA)-rich oil plus an oil rich in either SDA or ALA also attenuated egg yolk ALA and SDA contents (Experiment 1), or egg yolk and liver ALA contents (Experiment 2), respectively, as compared to feeding the SDA- or ALA-rich oils alone. Future work should focus on the lack of neutrality of OA and LA in relation to n-3 PUFA nutrition.

Integrating multiple chemical tracers to elucidate the diet and habitat of Cookiecutter Sharks

The Cookiecutter shark (Isistius brasiliensis) is an ectoparasitic, mesopelagic shark that is known for removing plugs of tissue from larger prey, including teleosts, chondrichthyans, cephalopods, and marine mammals. Although this species is widely distributed throughout the world’s tropical and subtropical oceanic waters, like many deep-water species, it remains very poorly understood due to its mesopelagic distribution. We used a suite of biochemical tracers, including stable isotope analysis (SIA), fatty acid analysis (FAA), and environmental DNA (eDNA), to investigate the trophic ecology of this species in the Central Pacific around Hawaii. We found that large epipelagic prey constituted a relatively minor part of the overall diet. Surprisingly, small micronektonic and forage species (meso- and epipelagic) are the most important prey group for Cookiecutter sharks across the studied size range (17–43 cm total length), with larger mesopelagic species or species that exhibit diel vertical migration also being important prey. These results were consistent across all the tracer techniques employed. Our results indicate that Cookiecutter sharks play a unique role in pelagic food webs, feeding on prey ranging from the largest apex predators to small, low trophic level species, in particular those that overlap with the depth distribution of the sharks throughout the diel cycle. We also found evidence of a potential shift in diet and/or habitat with size and season. Environmental DNA metabarcoding revealed new prey items for Cookiecutter sharks while also demonstrating that eDNA can be used to identify recent prey in stomachs frozen for extended periods. Integrating across chemical tracers is a powerful tool for investigating the ecology of elusive and difficult to study species, such as meso- and bathypelagic chondrichthyans, and can increase the amount of information gained from small sample sizes. Better resolving the foraging ecology of these mesopelagic predators is critical for effective conservation and management of these taxa and ecosystems, which are intrinsically vulnerable to overfishing and exploitation.

Effects of dietary incorporation of linseed oil with soybean isoflavone on fatty acid profiles and lipid metabolism-related gene expression in breast muscle of chickens

The meat quality of chicken is an important factor affecting the consumer's health. It was hypothesized that n-3 polyunsaturated fatty acid (n-3 PUFA) could be effectively deposited in chicken, by incorporating antioxidation of soybean isoflavone (SI), which led to improved quality of chicken meat for good health of human beings. Effects of partial or complete dietary substitution of lard (LA) with linseed oil (LO), with or without SI on growth performance, biochemical indicators, meat quality, fatty acid profiles, lipid-related health indicators and gene expression of breast muscle were examined in chickens. A total of 900 males were fed a corn-soybean meal diet supplemented with 4% LA, 2% LA + 2% LO and 4% LO and the latter two including 30 mg SI/kg (2% LA + 2% LO + SI and 4% LO + SI) from 29 to 66 days of age; each of the five dietary treatments included six replicates of 30 birds. Compared with the 4% LA diet, dietary 4% LO significantly increased the feed efficiency and had no negative effect on objective indices related to meat quality; LO significantly decreased plasma triglycerides and total cholesterol (TCH); abdominal fat percentage was significantly decreased in birds fed the 4% LO and 4% LO + SI diets. Chickens with LO diets resulted in higher contents of α-linolenic acid (C18:3n-3), EPA (C20:5n-3) and total n-3 PUFA, together with a lower content of palmitic acid (C16:0), lignoceric acid (C24:0), saturated fatty acids and n-6:n-3 ratio in breast muscle compared to 4% LA diet (P < 0.05); they also significantly decreased atherogenic index, thrombogenic index and increased the hypocholesterolemic to hypercholesterolemic ratio. Adding SI to the LO diets enhanced the contents of EPA and DHA (C22:6n-3), plasma total superoxide dismutase, reduced glutathione (GSH)/oxidized glutathione and muscle GSH content, while decreased plasma total triglyceride and TCH and malondialdehyde content in plasma and breast muscle compared to its absence (P < 0.05). Expression in breast muscle of fatty acid desaturase 1 (FADS1), FADS2, elongase 2 (ELOVL2) and ELOVL5 genes were significantly higher with the LO diets including SI than with the 4% LA diet. Significant interactions existed between LO level and inclusion of SI on EPA and TCH contents. These findings indicate that diet supplemented with LO combined with SI is an effective alternative when optimizing the nutritional value of chicken meat for human consumers.

Giblets and abdominal fat of pomegranate seed oil fed chickens as a source of bioactive fatty acids

The aim of present study was to determine whether chickens' (broilers Ross 308, n = 180, sex ratio 1:1) diet modification with different doses of grape or pomegranate seed oil will favourable change fatty acids and cholesterol content in selected giblets (liver and heart) or wastes (adipose tissue). It was also verify whether generated changes would make the giblets and wastes more valuable as dietary components or by-products for food industry. From 22 to 42 day of life, five diets were administered to chickens. Control grower diet (CON) contained 5% of soy oil, whereas in the experimental grower diets part of soy oil (1.5% or 2%) was replaced with specific amount of grape or pomegranate seed oil (GRAP 1.5; GRAP 2.0; POM 1.5; POM 2.0 respectively). Fatty acids and cholesterol content were determined with gas chromatography with flame-ionization detection. Pomegranate seed oil improved fatty acids profile more favourably than grape seed oil, which makes it a valuable additive in chickens' feeding. Abdominal fat of pomegranate seed oil supplemented chickens appeared to be the richest sources of rumenic acid and n3 polyunsaturated fatty acids, which allows to suggest its use in manufacturing of meat products to obtain foodstuffs rich in those essential nutrients. In principal component analysis (PCA), two principal components: PC1 and PC2, which were enough to explain 29.91% of variance of initial variables, allowed to a good separation of chickens fed with both doses of pomegranate seed oil from animals from control and grape seed oil fed groups. Because poultry addresses all nutritional, institutional and consumer requirements, enrichment of giblets in rumenic acid by pomegranate seed oil incorporation into chickens' diet may provide a valuable dietary source of bioactive fatty acids for consumers, especially of low-income countries.

Genes controlling polyunsaturated fatty acid synthesis are developmentally regulated in broiler chicks

1. The objective of this study was to characterise the regulation of the pathways that synthesise long-chain polyunsaturated fatty acids (PUFA) on developing adipose deposits in broiler embryos and chicks. Subcutaneous adipose depots were harvested from embryos and embryonic d E13, E15 and E17. Subcutaneous, abdominal and crop (neck) adipose, as well as liver, were collected at 7 and 14 d post-hatch. 2. Targeted RNA sequencing was used to quantify expression of 6 elongation of very long-chain fatty acid (ELOVL) genes, two isoforms of stearoyl-CoA desaturase (SCD and SCD5), and three fatty acid desaturases (FADS1, FADS2, and FADS6) in each depot and in the liver. Expression levels of marker genes for fatty acid oxidation and adipogenesis (peroxisome proliferator-activated receptor gamma (PPARG)) were quantified. Fatty acid composition of subcutaneous adipose was analysed using gas chromatograph-mass spectrometry (GC/MS). 3. Genes in the PUFA synthetic pathway were differentially expressed across developmental ages and between depots. These include elongase and desaturase genes, that have not previously been characterised in chicken. Correlation analyses identified subsets of co-regulated genes and fatty acids and highlighted relationships that may influence adipose metabolism and development. 4. It was concluded that PUFA synthesis is an active and dynamically regulated pathway in developing adipose deposits in the broiler chick. These data highlighted potential novel roles for specific elongase and desaturase genes in adipose deposition and metabolism.

COSMO-RS Based Prediction for Alpha-Linolenic Acid (ALA) Extraction from Microalgae Biomass Using Room Temperature Ionic Liquids (RTILs)

One of the essential fatty acids with therapeutic impacts on human health is known to be omega-3 polyunsaturated fatty acids (PUFA). More lately, ionic liquids (ILs) have received significant attention among scientists in overcoming the disadvantages of traditional solvents in biomass lipid extraction. However, the large pool of cations and anions possibly accessible will lead to a growing number of innovatively synthesized ILs. Nevertheless, the exhaustive measurement of all these systems is economically impractical. The conductive screening model for real solvents (COSMO-RS) is considered a precious approach with the availability of a few models to predict the characteristics of ILs. This work introduces the estimate of capacity values at infinite dilution for a range of ILs using COSMO-RS software as part of solid-liquid extraction. This favorable outcome presented that the capacity values of the IL molecules are extremely dependent on both anions and cations. Among the 352 combinations of cation/anion tested, short alkyl chain cations coupled with inorganic anions were found to be most efficient and therefore superior in the extraction method. Sulphate-, chloride-, and bromide-based ILs were found to have higher extraction capacities in contrast with the remainders, while propanoate revealed an extraordinary capacity when combined with ethyl-based cations. Eventually, the predicted results from COSMO-RS were validated through the experimentally calculated extraction yield of alpha-linolenic acid (ALA) compound from Nannochloropsis sp. microalgae. Three selected ILs namely [EMIM][Cl], [TMAm][Cl], and [EMPyrro][Br] were selected from COSMO-RS for empirical extraction purpose and the validation results pinpointed the good prediction capability of COSMO-RS.

Effects of dietary perilla seed oil supplementation on lipid metabolism, meat quality, and fatty acid profiles in Yellow-feathered chickens

This study evaluated the effect of the dietary replacement of 1% lard (CT) with 1% perilla oil (PO), 0.9% perilla oil + 0.1% anise oil (PA), or 0.9% perilla oil + 0.1% ginger oil (PG) on indices of lipid metabolism, antioxidant capacity, meat quality, and fatty acid profiles from Yellow-feathered chickens at day 63. Compared with the CT chickens, those given perilla oil had decreased (P < 0.05) plasma lipid levels including triglycerides (TG), total cholesterol (TCH), and low-density lipoprotein cholesterol (LDL-C). Hepatic TG, TCH levels, and fatty acid synthase activity were also decreased (P < 0.05) in chickens fed diets containing perilla oil. Abdominal fat percentage was significantly decreased in birds fed the PG compared to CT diets. Birds fed the PA or PG diets had increased (P < 0.05) hepatic total SOD, glutathione peroxidase, and glutathione-S-transferase than in chickens given PO alone. In addition, the content of reduced glutathione (GSH) in breast muscle was lower (P < 0.05) in birds fed PO compared with those given PG, and the reverse was true for content of malondialdehyde. Compared with the CT diet, the PO diet decreased breast muscle shear values and increased yellowness (b*) of breast muscle (P < 0.05). Birds fed the PA or PG diets had meat with better overall acceptability than those fed the CT diet. Chickens fed perilla oil diets exhibited higher contents of α-linolenic acid (C18:3n-3), DHA (22:6n-3), polyunsaturated fatty acids, and n-3 fatty acids, together with a lower content of myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), total saturated fatty acids, and n-6/n-3 ratio compared to controls (P < 0.05). These findings indicate that perilla oil has the potential to decrease lipid-related indices and improve fatty acid profiles of breast meat in chickens without adverse effect on antioxidant status or meat quality; this was even better when perilla oil was given together with anise oil or ginger oil.

The Effect of Dietary Camelina sativa Oil or Cake in the Diets of Broiler Chickens on Growth Performance, Fatty Acid Profile, and Sensory Quality of Meat

The aim of the present study was to determine the effect of supplementing the diets of broiler chickens with Camelina sativa oil or cake as a source of polyunsaturated fatty acids (PUFAs) on their growth performance, fatty acid profile, and sensory quality of meat. The 456 Ross 308 broilers aged 21-42 days were divided into 3 groups with 4 replicates of 38 birds in each. Chickens in the control group I (CTR) were fed a standard grower-finisher feed mixture containing 60 g/kg rapeseed oil. The experimental components, C. sativa oil-CSO (group II) or cake-CSC (group III), were included in a diet based on wheat and soybean at 40 and 100 g/kg, respectively. The use of Camelina oil and cake as feed components did not have a significant effect on the growth performance of the chickens. Analysis of the fatty acid profile in the lipids of the breast muscles showed that Camelina oil and cake reduced the content of monounsaturated fatty acids (p < 0.05) but increased the content of n-3 polyunsaturated fatty acids, especially α-linolenic acid (C18:3) (p < 0.01). Furthermore, both components reduced the ratio of n-6/n-3 PUFAs in the breast muscles (p < 0.01). Sensory analysis revealed that Camelina oil had a beneficial effect on meat juiciness, whereas Camelina cake slightly worsened the flavor and tastiness of the meat. In conclusion, supplementing the diet of broiler chickens with Camelina oil or cake can be an efficient method for modifying the fatty acid profile of the meat lipids in a beneficial way, without any negative impact on the growth performance of the chickens. According to the dietetic recommendations for humans, broiler chicken meat with a higher level of PUFA n-3 can be a good alternative source of these fatty acids in the human diet. Furthermore, Camelina oil improved the juiciness of breast meat.

Flaxseed and Carbohydrase Enzyme Supplementation Alters Hepatic n-3 Polyunsaturated Fatty Acid Molecular Species and Expression of Genes Associated with Lipid Metabolism in Broiler Chickens

Flaxseed is rich in α-linolenic acid and is used in broiler chicken diets to enrich tissues with n-3 fatty acids (FA). However, non-starch polysaccharides (NSP) in flaxseed decreases nutrient digestibility and limits the availability of n-3 FA. Addition of carbohydrase enzymes to flaxseed-based diets can decrease the anti-nutritive effects of NSP. We hypothesized that flaxseed and enzyme supplementation affect lipid content and alter expression of genes related to lipid metabolism in broiler liver. Five day-old broiler chicks were fed a corn-soybean basal diet with 0% flaxseed, a basal diet with 10% of flaxseed, or 10% flaxseed + 0.05% enzyme diet up to day 42 of growth. Total lipids, including long-chain (≥20C) n-3 FA and monounsaturated FA, were increased in flax-fed broiler livers. Enzyme addition reduced arachidonic acid and total long chain n-6 FA. These changes were similarly reflected in phosphatidylcholine lipid species. Dietary flax and enzyme treatments up-regulated PPARα target genes CPT1A and ACOX1 while reducing expression of de novo FA synthesis-related genes. This study concludes that flaxseed and enzyme supplementation in broiler diets enhances LC n-3 FA species, while reducing n-6 FA species in hepatic phospholipids (PL). Flaxseed-based diets changes the expression of genes involved in FA lipid metabolism without affecting growth or production performance in broilers.

Review on docosahexaenoic acid in poultry and swine nutrition: Consequence of enriched animal products on performance and health characteristics

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are linked to a variety of health benefits against human disorders and disease. However, the typical western diet is generally low in n-3 PUFA and high in n-6 PUFA, suggesting that the recommended intake of these essential fatty acids is seldom achieved. Therefore, dietary enrichment of animal meat and eggs with n-3 PUFA could help increase consumption of these fatty acids. Fish oils and microalgae (MA) are rich sources of long chain n-3 PUFA, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Feeding these marine products has been shown to increase DHA content of tissues and yolk, however, this may also lead to an increased requirement for anti-oxidants to prevent oxidative deterioration and associated negative sensory attributes. Nonetheless, increased DHA has been linked to promising results in animal growth, fertility, immunity and bone strength in both pigs and poultry. These findings suggest that feeding DHA-rich ingredients to mono-gastric can enrich human diets as well as providing additional benefits to the animal.

Comparative omega-3 fatty acid enrichment of egg yolks from first-cycle laying hens fed flaxseed oil or ground flaxseed

When laying hen diets are enriched with omega-3 polyunsaturated fatty acids to generate value-added eggs for human consumption markets, concentrations of alpha-linolenic (ALA), eicosapentaenoic (EPA), and docosahexaenoic acids (DHA) in the yolk can reach 250 mg/50 g whole egg. Flaxseed, a rich source of ALA, is commonly used for omega-3 enrichment; however, the impact of dietary flaxseed source (extracted oil vs. milled seed) on fatty acid transfer to egg yolk in laying hens is unknown. Therefore, transfer of ALA, EPA, and DHA into egg yolk from extracted flaxseed oil or milled flaxseed was evaluated in Hy-Line W-36 laying hens over an 8-week feeding period (25 to 33 wk old). Hens (n = 132) were randomly housed with 3 birds/cage (4 replicates/treatment) for each of the 11 treatment groups. Diets were isocaloric and consisted of a control diet, 5 flaxseed oil diets (0.5, 1.0, 2.0, 3.0, or 5.0% flaxseed oil), and 5 milled flaxseed diets (calculated flaxseed oil concentration from milled flaxseed 0.5, 1.0, 2.0, 3.0, 5.0%). Increasing dietary concentrations of flaxseed oil and milled flaxseed resulted in increased ALA, EPA, and DHA concentration in egg yolk, and fatty acid deposition from flaxseed oil was 2 times greater compared to milled flaxseed when fed at the same dietary inclusions (P < 0.01). Egg yolk EPA and DHA concentrations were not different due to oil or milled source (P = 0.21); however, increasing dietary inclusion rates of flaxseed oil from either source increased yolk EPA and DHA (P < 0.01). Hens fed either flaxseed oil or milled flaxseed resulted in reduced BW change as dietary concentrations increased (P = 0.02). Feed efficiency increased as flaxseed oil increased in concentration, while feeding milled flaxseed decreased feed efficiency (P = 0.01). Analysis of the nitrogen corrected apparent metabolizable energy of flaxseed oil resulted in 7,488 kcal/kg on an as-fed basis. Dietary flaxseed oil improved feed efficiency and increased ALA deposition into yolk compared to a milled source, demonstrating flaxseed oil to be a viable alternative for ALA egg enrichment.

RNA-Seq reveals differentially expressed genes affecting polyunsaturated fatty acids percentage in the Huangshan Black chicken population

Fatty acids metabolic products determine meat quality in chickens. Identifying genes associated with fatty acids composition could provide valuable information for the complex genetic networks of genes with underlying variations in fatty acids synthesis. RNA sequencing (RNA-Seq) was conducted to explore the chicken transcriptome from the thigh muscle tissue of 6 Huangshan Black Chickens with 3 extremely high and low phenotypic values for percentage of polyunsaturated fatty acids (PUFAs). In total, we obtained 41,139,108–44,901,729 uniquely mapped reads, which covered 74.15% of the current annotated transcripts including 18964 mRNA transcripts, across all the six thigh muscle tissue samples. Of these, we revealed 274 differentially expressed genes (DEGs) with a highly significant correlation with polyunsaturated fatty acids percentage between the comparison groups based on the ratio of PUFA/SFA. Gene ontology and pathway analysis indicated that the DEGs were enriched in particular biological processes affecting fatty acids metabolism, biosynthesis of unsaturated fatty acids (USFAs), and cell junction-related pathways. Integrated interpretation of differential gene expression and formerly reported quantitative trait loci (QTL) demonstrated that FADS2, DCN, FRZB, OGN, PRKAG3, LHFP, CHCHD10, CYTL1, FBLN5, and ADGRD1 are the most promising candidate genes affecting polyunsaturated fatty acids percentage.

Dietary High-Oleic Acid Soybean Oil Dose Dependently Attenuates Egg Yolk Content of n-3 Polyunsaturated Fatty Acids in Laying Hens Fed Supplemental Flaxseed Oil

Chickens can hepatically synthesize eicosapentaenoic acid (20:5 n-3) and docosahexaenoic acid (22:6 n-3) from α-linolenic acid (ALA; 18:3 n-3); however, the process is inefficient and competitively inhibited by dietary linoleic acid (LNA; 18:2 n-6). In the present study, the influence of dietary high-oleic acid (OLA; 18:1 n-9) soybean oil (HOSO) on egg and tissue deposition of ALA and n-3 polyunsaturated fatty acids (PUFA) synthesized from dietary ALA was investigated in laying hens fed a reduced-LNA base diet supplemented with high-ALA flaxseed oil (FLAX). We hypothesized that reducing the dietary level of LNA would promote greater hepatic conversion of ALA to very long-chain (VLC; >20C) n-3 PUFA, while supplemental dietary HOSO would simultaneously further enrich eggs with OLA without influencing egg n-3 PUFA contents. Nine 51-week-old hens each were fed 0, 10, 20, or 40 g HOSO/kg diet for 12 weeks. Within each group, supplemental dietary FLAX was increased every 3 weeks from 0 to 10 to 20 to 40 g/kg diet. Compared to controls, dietary FLAX maximally enriched the total n-3 and VLC n-3 PUFA contents in egg yolk by 9.4-fold and 2.2-fold, respectively, while feeding hens 40 g HOSO/kg diet maximally attenuated the yolk deposition of ALA, VLC n-3 PUFA, and total n-3 PUFA by 37, 15, and 32%, respectively. These results suggest that dietary OLA is not neutral with regard to the overall process by which dietary ALA is absorbed, metabolized, and deposited into egg yolk, either intact or in the form of longer-chain/more unsaturated n-3 PUFA derivatives.

Relationship between the fatty acid composition of uropygial gland secretion and blood of meat chickens receiving different dietary fats

Manipulation of the fatty acid composition of chicken feed has been shown to be effective for improving the nutritional value of chicken products. Currently, however, evaluation of the effectiveness of this approach requires invasive blood sampling or post mortem tissue sampling of the birds. Preen oil can be collected non-invasively from live birds. So this study aimed to test the hypothesis that the fatty acid composition of preen oil reflects that of the blood. Male and female meat chickens (Cobb 500) were fed a diet supplemented with 4% (w/w) flaxseed oil (high n-3 polyunsaturates) or beef tallow (mostly monounsaturates and saturates) for 6 weeks. Preen oil and whole blood samples (n = 9 birds per sex/diet treatment group) were collected freshly post mortem for fatty acid analysis. Preen oil analysis showed that ~97% of fatty acids were saturates, with a small percentage of n-6 polyunsaturates and traces of other types. There were negligible n-3 polyunsaturates in preen oil. Proportions of some saturated fatty acids were slightly, but significantly, affected by diet (C16:0 (P < 0.05) and C17:0 (P < 0.01)) or by gender (C10:0 and C18:0) (P < 0.05). Some fatty acids with odd numbers of carbon atoms (e.g. C17:0 and C19:0) were found in relatively high concentrations in preen oil, despite not being detectable in either the diet or blood. In conclusion, the fatty acid composition of preen oil does not accurately reflect the fatty acid profile of the blood; it is not, therefore, a suitable alternative for determining fatty acid status of meat chickens.

Effects of Dietary n-6:n-3 PUFA Ratios on Lipid Levels and Fatty Acid Profile of Cherry Valley Ducks at 15-42 Days of Age

The objective of this study was to investigate the effects of dietary n-6:n-3 PUFA ratio on growth performance, serum and tissue lipid levels, fatty acid profile, and hepatic expression of fatty acid synthesis genes in ducks. A total of 3168 15-day old ducks were fed different n-6:n-3 PUFA ratios: 13:1 (control), 10:1, 8:1, 6:1, 4:1, and 2:1. The feeding trial lasted 4 weeks. Our results revealed that dietary n-6:n-3 PUFA ratios had no effects on growth performance. The 2:1 group had the highest serum triglyceride levels. Serum total cholesterol and HDL levels were higher in the 13:1 and 8:1 groups than in the 6:1 and 2:1 groups. The concentration of C18:3n-3 in serum and tissues (liver and muscle) increased with decreasing dietary n-6:n-3 PUFA ratios. The hepatic expression of FADS2, ELOVL5, FADS1, and ELOVL2 increased on a quadratic function with decreasing dietary n-6:n-3 PUFA ratios. These results demonstrate that lower dietary n-6:n-3 PUFA ratios had strong effects on the fatty acid profile of edible parts and the deposition of n-3 PUFAs in adipose tissue of ducks.

Evaluation of fatty acid metabolism and innate immunity interactions between commercial broiler, F1 layer × broiler cross and commercial layer strains selected for different growth potentials

Background

The broiler industry has undergone intense genetic selection over the past 50 yr. resulting in improvements for growth and feed efficiency, however, significant variation remains for performance and growth traits. Production improvements have been coupled with unfavourable metabolic consequences, including immunological trade-offs for growth, and excess fat deposition. To determine whether interactions between fatty acid (FA) metabolism and innate immunity may be associated with performance variations commonly seen within commercial broiler flocks, total carcass lipid %, carcass and blood FA composition, as well as genes involved with FA metabolism, immunity and cellular stress were investigated in male birds of a broiler strain, layer strain and F1 layer × broiler cross at d 14 post hatch. Heterophil: lymphocyte ratios, relative organ weights and bodyweight data were also compared.

Results

Broiler bodyweight (n = 12) was four times that of layers (n = 12) by d 14 and had significantly higher carcass fat percentage compared to the cross (n = 6; P = 0.002) and layers (P = 0.017) which were not significantly different from each other (P = 0.523). The carcass and whole blood FA analysis revealed differences in the FA composition between the three groups indicating altered FA metabolism, despite all being raised on the same diet. Genes associated with FA synthesis and β-oxidation were upregulated in the broilers compared to the layers indicating a net overall increase in FA metabolism, which may be driven by the larger relative liver size as a percentage of bodyweight in the broilers. Genes involved in innate immunity such as TLR2 and TLR4, as well as organelle stress indicators ERN1 and XBP1 were found to be non-significant, with the exception of high expression levels of XBP1 in layers compared to the cross and broilers. Additionally there was no difference in heterophil: lymphocytes between any of the birds.

Conclusions

The results provide evidence that genetic selection may be associated with altered metabolic processes between broilers, layers and their F1 cross. Whilst there is no evidence of interactions between FA metabolism, innate immunity or cellular stress, further investigations at later time points as growth and fat deposition increase would provide useful information as to the effects of divergent selection on key metabolic and immunological processes.

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.

Determinants of plasma phospholipid arachidonic and docosahexaenoic acids among adolescent girls in central Mozambique - possible roles of iron and zinc

We explored if linoleic acid (LA) and alpha-linolenic acid (ALA) will be efficiently converted to arachidonic acid (AA) and docosahexaenoic acid (DHA) in the adolescent girls (aged 15-18 years, n=145) in Mozambique consuming habitually low fat diet and if low iron and/or zinc status predicts the conversion. Total fat, LA and ALA intakes were 15-19%, 1.2-3.5% and 0.2-0.3% of energy, respectively in three areas. Iron and zinc intake varied between 9.6-12.3mg/day and 3.6-5.0mg/day. Significant negative association of plasma AA was found with plasma LA and ALA and significant positive association with serum ferritin. Plasma DHA associated, negatively with plasma LA and ALA. We showed that in a population with low intakes of LA and ALA, the proportions of phospholipid LA and ALA determines the relative proportions of AA and DHA and low iron status probably attenuates the conversion of LA to AA.

Enhanced polyunsaturated fatty acids production in Mortierella alpina by SSF and the enrichment in chicken breasts

BACKGROUND

Distiller's dried grains with solubles (DDGS) and soybean meal were used as the substrates for the production of polyunsaturated fatty acids (PUFA) in solid-state fermentation (SSF) by Mortierella alpine. These fermented products were fed to laying hens. PUFA enrichment from chicken breasts was studied.

METHODS

The maximum productivity of PUFA was achieved under optimized process condition, including 1% w/w yeast extract as additive, an incubation period of 5 days at 12°C, 10% v/w inoculum level, 75% moisture content, and pH 6.0. The hens were then fed with ration containing soybean DDGS, rapeseed oil, soybean oil, and peanut oil. The control group was fed with basal ration.

RESULTS

Under the optimal condition, M. alpine produced total fatty acids (TFA) of 182.34 mg/g dry substrate. It has better mycelial growth when soybean meal was added to DDGS (SDDGS). PUFA in fermentation product increased with higher soybean meal content. The addition of 70% soybean meal to DDGS substrate yielded 175.16 mg of TFA, including 2.49 mg eicosapentaenoic acid (EPA) and 5.26 mg docosahexaenoic acid (DHA). The ratios of ω-6/ω-3 found in chicken breasts fat were all lower than that found in control by 36.98, 31.51, 18.15, and 12.63% for SDDGS, rapeseed oil, soybean oil, and peanut oil, respectively.

CONCLUSIONS

This study identified an optimized SSF process to maximize PUFA productivity by M. alpine as the strain. This PUFA-enriched feed increased the PUFA contents as well as the proportions of ω-6 and ω-3 in chicken breasts and liver.

Original Research: Effect of various dietary fats on fatty acid profile in duck liver: Efficient conversion of short-chain to long-chain omega-3 fatty acids

Omega-3 fatty acids, especially long-chain omega-3 fatty acids, have been associated with potential health benefits for chronic disease prevention. Our previous studies found that dietary omega-3 fatty acids could accumulate in the meat and eggs in a duck model. This study was to reveal the effects of various dietary fats on fatty acid profile and conversion of omega-3 fatty acids in duck liver. Female Shan Partridge Ducks were randomly assigned to five dietary treatments, each consisting of 6 replicates of 30 birds. The experimental diets substituted the basal diet by 2% of flaxseed oil, rapeseed oil, beef tallow, or fish oil, respectively. In addition, a dose response study was further conducted for flaxseed and fish oil diets at 0.5%, 1%, and 2%, respectively. At the end of the five-week treatment, fatty acids were extracted from the liver samples and analyzed by GC-FID. As expected, the total omega-3 fatty acids and the ratio of total omega-3/omega-6 significantly increased in both flaxseed and fish oil groups when compared with the control diet. No significant change of total saturated fatty acids or omega-3 fatty acids was found in both rapeseed and beef tallow groups. The dose response study further indicated that 59-81% of the short-chain omega-3 ALA in flaxseed oil-fed group was efficiently converted to long-chain DHA in the duck liver, whereas 1% of dietary flaxseed oil could produce an equivalent level of DHA as 0.5% of dietary fish oil. The more omega-3 fatty acids, the less omega-6 fatty acids in the duck liver. Taken together, this study showed the fatty acid profiling in the duck liver after various dietary fat consumption, provided insight into a dose response change of omega-3 fatty acids, indicated an efficient conversion of short- to long-chain omega-3 fatty acid, and suggested alternative long-chain omega-3 fatty acid-enriched duck products for human health benefits.

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.

Creating ω-3 Fatty-Acid-Enriched Chicken Using Defatted Green Microalgal Biomass

This study was to create an ω-3 (n-3) fatty-acid-enriched chicken product using defatted green microalgae (DGA, Nannochloropsis oceanica) biomass out of biofuel research. Hatching Ross broiler chicks were fed a corn-soybean meal diet containing 0 (control), 2, 4, 8, or 16% DGA for 6 weeks (n = 6 cages/diet). The DGA inclusion resulted in a linear (p < 0.001) increase in total n-3 fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) in plasma, liver, breast, and thigh at weeks 3 and 6. The increase in the breast EPA + DHA by the 16% DGA diet reached 60-fold (p < 0.0001) over the control. The 8 and 4% DGA diets elevated (p < 0.05) liver mRNA levels of Δ-9 (88%) and Δ-6 (96) desaturases. In conclusion, 8-16% of the DGA can be added in diets for broilers to produce a n-3 fatty-acid-enriched chicken meat.

A comparative assessment of the fatty acid profiles and antioxidant status of supermarket eggs

Nutrient deposition in eggs is largely dictated by the dietary composition of laying hen feed, particularly in terms of specific fatty acids and antioxidants. In the present study, the nutritional quality of a range of commercially available egg varieties, marketed as omega-3 enriched; corn-fed; free range and standard caged, were assessed by determining fatty acid profiles and antioxidant status. Across each egg variety, significant differences were observed in key fatty acids such as palmitic, oleic, linoleic, alpha-linolenic and docosahexaenoic acid (DHA) (P ≤ 0.05). Egg yolks enriched with a stated dietary source of omega-3 fatty acid DHA were shown to have significantly improved levels of DHA (P ≤ 0.05), approximately 4.5-fold higher than standard caged eggs. Compared with free range, corn fed and caged, eggs from diets enriched with a source of omega-3 were shown to have considerably altered omega-6: omega-3 ratios, amounting to 1.5–2.1 fold reductions. Yolk antioxidant activity was improved for omega-3 enriched eggs, particularly in hexane fractionated samples. The inclusion of omega-3 fatty acids to the diet resulted in eggs with improved DHA contents and antioxidant status, highlighting the importance of poultry diet composition for egg nutritional quality.

Effect of Different Dietary n-6 to n-3 Fatty Acid Ratios on the Performance and Fatty Acid Composition in Muscles of Broiler Chickens

The objective of this study was to investigate the different dietary ratios of n-6 to n-3 (n-6/n-3) fatty acid (FA) on performance and n-6/n-3 FA in muscles of broiler chickens. A total of 300 one-day-old Cobb chicks were randomly assigned to 3 treatments of 10 replicates in each (10 birds/replicate). Birds were fed on a corn-soybean meal-based diet containing 1% oil during starter (day 1 to 21) and 2% oil during finisher (day 22 to 39) phases, respectively. Treatments of high, medium and low dietary n-6/n-3 FA were formulated by replacing rice bran oil with linseed oil to achieve n-6/n-3 FA close to >20:1, 10:1 and 5:1, respectively. Average daily gain, average daily feed intake, and feed conversion ratio were similar (p>0.05) among the treatments. Serum glucose, cholesterol and triglycerides concentrations were not affected (p>0.05) by dietary treatments. In breast, concentration of C18:3n-3 was significantly greater (p = 0.001) for medium and low vs high n-6/n-3 FA, while concentrations of C20:5n-3, C22:6n-3, total n-3 FA, and n-6/n-3 FA were significantly higher for low vs medium, and medium vs high dietary n-6/n-3 FA. In contrast, concentrations of C18:2 and mono-unsaturated FA (MUFA) were lower for low vs high dietary n-6/n-3 FA. In thigh muscles, concentrations of C20:5n-3 were higher (p<0.05) for medium and low vs high dietary n-6/n-3 FA, and concentrations of C18:3n-3, C22:6, and n-3 FA were greater (p<0.05) for medium vs high, low vs medium dietary n-6/n-3 FA. However, concentrations of C18:1, MUFA, n-6/n-3 were lower (p<0.05) for low and medium vs high dietary n-6/n-3 FA. In conclusion, lowering the dietary n-6/n-3 FA did not affect the performance of chickens, but enhanced beneficial long-chain n-3 FA and decreased n-6/n-3 FA in chicken breast and thigh, which could be advantageous for obtaining healthy chicken products.

Functional characterization of the duck and turkey fatty acyl elongase enzymes ELOVL5 and ELOVL2

In most Western countries, the consumption of fish is low and insufficient to provide the recommended daily intake of the n-3 (ω-3) long-chain polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). Poultry has the potential to be a sustainable source of EPA and DHA if poultry species are capable of synthesizing these n-3 PUFAs from dietary plant-derived α-linolenic acid (ALA; 18:3n-3). In most animals, the elongation of very long-chain fatty acids (ELOVL) enzyme ELOVL2 is essential for conversion of dietary ALA to DHA because only ELOVL2 and not ELOVL5 can elongate docosapentaenoic acid (DPA; 22:5n-3) to 24:5n-3, the precursor of DHA. The chicken is the only poultry species in which elongase enzymes have been functionally characterized, and chicken ELOVL5 had unique DPA-to-24:5n-3 activity, which may enable chickens to synthesize more DHA than other animals. By using a yeast expression system, we examined the duck and turkey elongases, ELOVL2 and ELOVL5, to understand if all poultry species have similar potential to synthesize EPA and DHA. The duck and turkey ELOVL5 enzymes were active with C18-20 PUFAs only. The duck ELOVL2 had a broad substrate specificity with C18-22 PUFAs, whereas the turkey ELOVL2 was active only with EPA and C22 PUFAs. Both duck and turkey ELOVL2 enzymes catalyzed 2 rounds of EPA elongation, with the products being DPA and its elongation product, 24:5n-3. With exogenous DPA, both duck and turkey ELOVL2 synthesized 24:5n-3, with the duck ELOVL2 being more active than the turkey ELOVL2. The reason for the lack of DPA elongation activity by the duck and turkey ELOVL5 enzymes compared with the chicken ELOVL5 could not be elucidated by protein sequence comparisons. By using the elongase enzyme activities only as a predictor of DHA synthesis, ducks may have a similar ability to chickens to convert increasing dietary ALA to DHA.

Modulation of the insulin anabolic signalling cascade in growing chickens byn-3 PUFA

n-3 PUFA are crucial for health and development. Their effects as regulators of lipid and glucose metabolism are well documented. They also appear to affect protein metabolism, especially by acting on insulin sensitivity. The aim of the present study was to investigate the role ofn-3 PUFA, i.e. the precursor α-linolenic acid (ALA) 18 : 3n-3 or long-chain PUFA (LC-PUFA), in chickens, by focusing on their potential function as co-regulators of the insulin anabolic signalling cascade. Ross male broilers were divided into six dietary treatment groups. Diets were isoproteic (22 % crude protein) and isoenergetic (12·54 MJ metabolisable energy/kg) and contained similar lipid levels (6 %) provided by different proportions of various lipid sources: oleic sunflower oil rich in 18 : 1n-9 as control; fish oil rich in LC-PUFA; rapeseed and linseed oils providing ALA. The provision of diets enriched withn-3 PUFA, i.e. rich in LC-PUFA or in the precursor ALA, for 3 weeks improved the growth performance of chickens, whereas that of only the ALA diet enhanced the development of the pectoralis major muscle. At 23 d of age, we studied the insulin sensitivity of the pectoralis major muscle and liver of chickens after an intravenous injection of insulin or saline. The present results indicate that the activation patterns ofn-3 PUFA are different in the liver and muscles. An ALA-enriched diet may improve insulin sensitivity in muscles, with greater activation of the insulin-induced 70 kDa ribosomal protein S6 kinase/ribosomal protein S6 pathway involved in the translation of mRNA into proteins, thereby potentially increasing muscle protein synthesis and growth. Our findings provide a basis on which to optimise dietary fatty acid provision in growing animals.