n-3 enrichment of chicken meat using fish oil: alternative substitution with rapeseed and linseed oils

Composition of meat and offal from weaned and fattened rabbits and results of stereospecific analysis of triacylglycerols and phosphatidylcholines

BACKGROUND

Rabbit meat has excellent nutritive properties. The purpose of this study was to characterize rabbit meat and offal; in particular, the lipid fraction was studied in order to evaluate total and positional fatty acid (FA) compositions of triacylglycerol (TAG) and phosphatidylcholine (PC) fractions. Eight samples of weaned and eight of fattened rabbits were considered.

RESULTS

Fattened rabbit meat contained slightly higher protein percentage content (P < 0.05) in comparison to weaned (20.1% versus 18.0%). Calcium content was higher in meat than in offal, unlike sodium, iron, zinc, manganese and copper. The cholesterol content in offal was much higher than in meat. FA profiles of total lipid showed a high percentage of unsaturated fatty acids and an n-6/n-3 ratio of 10.3 for fattened rabbit meat. Stereospecific analysis of TAG and PC was carried out on an eight-sample pool of each meat and offal from weaned and fattened rabbits. In all samples the sn-2-position was prevalently esterified with oleic and linoleic acids in TAG, with polyunsaturated fatty acids in PC.

CONCLUSION

Lipids from rabbit meat presented higher content of monounsaturated FA and lower n-6/n-3 ratio in comparison to offal, which was characterized by higher cholesterol and mineral levels.

Effect of n-3 fatty acids on immune function in broiler chickens

There is interest in the enrichment of poultry meat with long-chain n-3 polyunsaturated fatty acids in order to increase the consumption of these fatty acids by humans. However, there is concern that high levels of n-3 polyunsaturated fatty acids may have detrimental effects on immune function in chickens. The effect of feeding increasing levels of fish oil (FO) on immune function was investigated in broiler chickens. Three-week-old broilers were fed 1 of 4 wheat-soybean basal diets that contained 0, 30, 50, or 60 g/kg of FO until slaughter. At slaughter, samples of blood, bursa of Fabricius, spleen, and thymus were collected from each bird. A range of immune parameters, including immune tissue weight, immuno-phenotyping, phagocytosis, and cell proliferation, were assessed. The pattern of fatty acid incorporation reflected the fatty acid composition of the diet. The FO did not affect the weight of the spleen, but it did increase thymus weight when fed at 50 g/kg (P < 0.001). Fish oil also lowered bursal weights when fed at 50 or 60 g/kg (P < 0.001). There was no significant effect of FO on immune cell phenotypes in the spleen, thymus, bursa, or blood. Feeding 60 g/kg of FO significantly decreased the percentage of monocytes engaged in phagocytosis, but it increased their mean fluorescence intensity relative to that of broilers fed 50 g/kg of FO. Lymphocyte proliferation was significantly decreased after feeding broiler chickens diets rich in FO when expressed as division index or proliferation index, although there was no significant effect of FO on the percentage of divided cells. In conclusion, dietary n-3 polyunsaturated fatty acids decrease phagocytosis and lymphocyte proliferation in broiler chickens, highlighting the need for the poultry industry to consider the health status of poultry when poultry meat is being enriched with FO.

Effect of dietary fish oil on n-3 fatty acid content of meat from broiler chickens fed low protein diets

An experiment was carried out to evaluate the effects of dietary fish oil and crude protein (CP) levels on fatty acid composition of the thigh and breast tissues of broiler chickens. Four hundred and fifty, 1-day-old mixed-sex broiler chicks were used in a completely randomised design with factorial arrangement consisting of two dietary CP levels (21 v. 18.0% and 19 v. 17.1% for grower and finisher diets, respectively), and three levels of fish oil inclusion (0, 2 or 4%). Specific increases in eicosapentaenoic acid (EPA, 20 : 5) and docosahexaenoic acid (DHA, 22 : 6) were observed in breast and thigh tissues as a response to increased fish oil supplementation. The n-6 : n-3 fatty acid ratio in breast and thigh meat samples decreased (P < 0.05) in birds fed low protein diets, but dietary protein level led to no alteration in the total n-3 fatty acids of the tissues (P > 0.05). Thigh tissue of chickens fed low protein diets had a higher concentration of DHA (P < 0.05), while the DHA and EPA concentrations in breast tissue were not affected by dietary protein level (P > 0.05). Results of the present study showed that fish oil can be used to fortify EPA and DHA levels in chicken meat and there is an interaction between dietary fatty acids and protein level on meat oxidative stability, and a reduction in dietary protein level may lead to a better oxidative stability of chicken meat.

Influence of dietary fish oil supplementation on humoral immune response and some selected biochemical parameters of broiler chickens

The objective of this experiment was to evaluate the influence of fish oil (FO) supplementation in the diet of broiler chickens on the humoral immune response as well as some blood parameters. Two hundred and sixteen one day old broiler chickens were divided into four dietary groups 0, 1, 2, or 4% FO with 3 replicates of 18 birds. Four chicks randomly selected and marked from each replicate were immunized intramuscularly with 0.2 ml of 5% sheep red blood cells (SRBC) as a non-infectious antigen, at the ages of 15 and 35 days and blood samples were taken 7 days after each immunization. The highest BW was observed in the 2% FO dietary group (T3), followed by T2 (P<0.01). The serum cholesterol and triglyceride levels significantly decreased in the FO groups at the age of 42 days (P<0.01). In addition, the inclusion of FO in broiler diets significantly increased the blood glucose (G) level and decreased the total protein (TP), albumin (A) and globulin (GL) concentrations. Fish oil-treated birds had significantly more serum antibody (predominantly immunoglobulin M, IgM) to SRBC than the control group. The highest response to primary and secondary injections of SRBC after 7 days, were detected for group 4 (4% FO), followed by 2% FO group (P<0.05). The results indicate that the addition of 2 % FO to broiler chick's diet may stimulate the development of the immune response and improve blood indices, while 4% level was not recommended because of probable off-flavours in the product.

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.

Influence of oils on the Taihe Silky Fowl production performances and fatty acids composition of the meat

Focus on the enrichment of eggs and poultry meat with polyunsaturated fatty acids has increased given their important roles in the human health. The inclusion of polyunsaturated fatty acids (especially n-3 fatty acids, n-3 FA) is achieved by different biological methods. The objective of this study was to investigate the effects of inclusion of different oils into the feed on the production performances and fatty acids composition of the meat in Taihe Silky Fowl. A total of 80 fowls were selected at 8 weeks and randomly divided into four groups and fed with basal diet, basal diet + 4% fish oil, basal diet + 4% soybean oil and basal diet + 4% palm oil within 3 weeks respectively. The results showed that: the fowls fed with the diet inclusion of 4% fish oil had higher total gain, average daily gain, the second and the third week average daily gain than those in control group (p< 0.05). Also, inclusion of fish oil could improve the content of C22:5 n-3 and C22:6 n-3 polyunsaturated fatty acids in the meat significantly compared with the other three groups (p < 0.01). Meanwhile, C18:3 n-3 and C18:4 n-3 polyunsaturated fatty acids were also higher than in the other three groups (p< 0.05 and 0.01). Oils Supplementation could enhance C14:0 and C16:0 (p< 0.05) level, but they did not affect the total saturated fatty acids in the meat. Compared with the control group, fish oil inclusion could lower the C18:2 n-6 level, higher the C18:3 n-6, C22:4 n-6 and C22:5 n-6 polyunsaturated fatty acids in the meat (p < 0.05). Moreover, diets supplied with 4% fish oil reduced the total n-6 polyunsaturated fatty acids level and enhanced the total n-3 polyunsaturated fatty acids level in the meat, which resulted in that the ratio of n-3/n-6 was improved, and could meet the need of human body.

PCDD/F and DL-PCB levels in meat from broilers and rabbits fed with fish-oil enriched feeds

The aim of this study was to assess the effect on the final levels of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in meat when fats, in particular fish oils, are included as ingredients in feeds. Two types of animals (broilers and rabbits) were fed with three different experimental feeds containing varying amounts of two selected fish oils. PCDD/Fs and DL-PCBs were determined in the fish oils, the feeds and in the animals' meat. For broilers, PCDD/F and DL-PCB profiles in meat samples were similar to those found in the corresponding feeds, even though bioaccumulation of the highest chlorinated PCDD/F congeners seemed to decrease. Depending on the treatment, PCDD/F and the sum of PCDD/F and DL-PCB levels were 1.11-4.60 and 6.03-16.71 pg WHO-TEQ/g fat, respectively. For most of the cases, these values exceeded the maximum established by the Commission Regulation (EC) No. 1881/2006. In contrast, the levels of these contaminants in the corresponding feeds ranged from 0.11 to 0.54 pg WHO-TEQ/g, in the case of PCDD/Fs, and from 0.59 to 1.75 pg WHO-TEQ/g, when DL-PCBs were also included. These levels were, in general, below the maximum allowed by the Commission Directive 2006/13/EC. The results of the experiments with rabbits were not as conclusive as those for broilers although bioaccumulation appeared to be slower.

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.

Efeito do consumo de óleo de linhaça e de vitamina E no desempenho e nas características de carcaças de frangos de corte

Foi avaliado o efeito da utilização de óleo de linhaça na ração, em substituição ao óleo de soja em diferentes proporções, e de vitamina E, até o nível de 400mg/kg de ração, sobre o desempenho e a composição de carcaça de frangos de corte. O desempenho produtivo foi avaliado com base em pesagens das aves e da ração aos 21 e 49 dias de idade. No 49º dia, as aves foram abatidas, e os rendimentos de carcaça e dos principais cortes comerciais e a porcentagem de vísceras e de gordura abdominal foram avaliados. A composição da fração oleosa da ração, de forma geral, não interferiu nos parâmetros de desempenho avaliados (P>0,05). Os machos consumiram mais ração e ganharam mais peso que as fêmeas (P<0,01). As fêmeas apresentaram, em geral, pior conversão alimentar, associada à maior deposição de gordura abdominal. Os machos apresentaram maior porcentagem de coxa com sobrecoxa em relação ao peso da carcaça eviscerada, e as fêmeas apresentaram maior porcentagem de peito. A porcentagem de asas e vísceras não diferiu entre os sexos.

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

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

Influence of different dietary doses of n-3- or n-6-rich vegetable fats and alpha-tocopheryl acetate supplementation on raw and cooked rabbit meat composition and oxidative stability

This study evaluates the effects of replacing beef tallow added to rabbit feeds (3% w/w) by different doses (0%, 1.5% and 3% w/w) of n-6- or n-3-rich vegetable fat sources (sunflower and linseed oil, respectively) and alpha-tocopheryl acetate supplementation (0 and 100 mg/kg) on the fatty acid composition, alpha-tocopherol content, and oxidation levels [assessed by analyzing thiobarbituric acid (TBA) and lipid hydroperoxide values] in rabbit meat. We also measured these parameters after cooking and refrigerated storage of cooked rabbit meat. Both dietary alpha-tocopheryl acetate supplementation and the dose and source of fat added to feeds influenced meat fatty acid composition, modifying the n-6/n-3 ratio, which was more nutritionally favorable when linseed oil was used. Furthermore, the addition of linseed oil and the supplementation with alpha-tocopheryl acetate enhanced long-chain PUFA biosynthesis. However, the addition of 3% linseed oil increased meat oxidation, and although it was reduced by dietary supplementation with alpha-tocopheryl acetate in raw meat, this reduction was not as effective after cooking. Therefore, dietary supplementation with 1.5% linseed oil plus 1.5% beef tallow and with alpha-tocopheryl acetate would be recommended to improve the nutritional quality of rabbit meat.

Effect of dietary fatty acid pattern on growth, body fat composition and antioxidant parameters in broilers

The effects of dietary fat supplementation on performance, fatty acid (FA) composition of tissues and antioxidant defence system of broilers were studied. Male broilers were placed in 20 floor pens (60 broilers per pen). The broilers were fed by diets with added different energy sources: lard (L); sunflower oil (SFO); soybean oil (SBO); and linseed oil (LSO). The treatments did not modify significantly growth performance and feed intake of the broilers. There was no effect of dietary FA pattern on reduced glutathione level and glutathione peroxidase activity of plasma, erythrocyte and liver samples. However, higher PUFA content of the diet resulted in a significant increase in malondialdehyde level of erythrocytes and liver. The broilers fed LSO diet more effectively maintained their antioxidant status with enhanced plasma radical scavenger capacity. FA composition in tissues reflected the FA pattern of the diets, although proportion of FAs with four or more double bonds was metabolic specific. LSO diet increased the level of C18:3, C20:5 and C22:6 in tissue lipids in relation to L, SFO and SBO diets. Significantly increased plasma radical scavenging capacity in concert with the enhanced C20:5 and C22:6 proportion in liver and muscle during LSO feeding indicate metabolic changes to counteract the oxidative injury. This may be related to the compounds produced after different biochemical pathways of n-6 and n-3 FAs.

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

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

Regulation of taste-active components of meat by dietary leucine

1. Regulation of meat taste is one effective method for improvement of meat quality. In this study, effects of dietary leucine (Leu) content on taste-active components, especially free glutamate (Glu), in meat were investigated. 2. Broiler chickens (28 d old) were fed on diets with graded dietary Leu content (100, 130 or 150% of Leu requirement in NRC, 1994) for 10 d before marketing. Taste-active components of meat (free amino acids and ATP metabolites) and sensory score of meat soup were estimated. 3. Free Glu content, the main taste-active component of meat, was significantly increased by dietary Leu. Compared with the Leu 130% group, free Glu was increased by 17% in the Leu 100% group. Free Glu of meat tended to decrease in the Leu 150% group. In contrast, inosine monophosphate content in meat did not change among all groups. 4. Sensory evaluation of meat soup from the Leu 100 and 150% groups showed that they had different meat tastes. Sensory scores of overall preference, umami taste and chicken-like taste were significantly higher in the Leu 100% group. 5. These results suggest that dietary Leu content is a regulating factor of free Glu in meat. Decreasing dietary Leu induces an increase in the free Glu content of meat and improves meat taste.

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.

Arachidonic acid and long-chain n-3 polyunsaturated fatty acid contents in meat of selected poultry and fish species in relation to dietary fat sources

Arachidonic acid (AA) content, long-chain n-3 polyunsaturated fatty acid (PUFA) equivalent [LCE; calculated as 0.15 x linolenic acid (LA) + eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)], and PUFA n-6/PUFA n-3 ratio were determined in meat [breast meat (BM), thigh meat (TM), and fillets (F), respectively] within four sets of chickens, five sets of turkeys, one set of common carp, and four sets of rainbow trout, fed either commercial diet or diets with manipulated PUFA n-3 and PUFA n-6 contents. AA content was within the range of 20 mg/100 g (F of rainbow trout fed the diet with linseed oil, LO) to 138 mg/100 g (TM of chickens fed restrictively the diet based on maize to the age of 90 days). AA content in BM of turkeys fed the diet with LO or fish oil (FO) did not differ (P > 0.05) from that of rainbow trout F. LCE was in the range of 16 mg/100 g (BM of turkeys fed a commercial feed mixture) to 681 mg/100 g (F of rainbow trout fed a commercial feed mixture). With regard to BM, only turkeys fed the diet with LO deposited more (P < 0.01) LCE (71 mg/100 g) as compared to all other poultry sets except turkeys fed the diet with FO (123 mg/100 g). Apart from all fish samples, also both BM and TM of turkeys fed the diet with either LO or FO met the recommended value of the PUFA n-6/PUFA n-3 ratio (<4). AA content in the tissue increased significantly (P < 0.001) with increasing dietary LA in both all chicken tissues and all turkey tissues, which is contrary to the suggested strong metabolic regulation of the AA formation. When all tissues within all animal species were taken as a one set, both AA percentage and EPA + DHA percentage in the tissue (Y, %) decreased (P < 0.001) with increasing fat content in the tissue (X, %), according to the equation Y = 4.7 - 0.54X (R (2) = 0.41) and Y = 6.0 - 0.33X (R (2) = 0.35), respectively. AA content in chicken BM, chicken TM, and turkey BM, respectively, decreased linearly (P < 0.01) with increasing live weight reached at the slaughter age.

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.

Influence of the dietary polyunsaturation level on chicken meat quality: lipid oxidation

The present study was carried out to evaluate the influence of increasing amounts of dietary polyunsaturated fatty acids (PUFA) and alpha-tocopheryl acetate (alpha-TA) supplementation on lipid oxidation of raw and cooked thigh meat stored under refrigeration. One hundred ninety-two female, 1-d-old, broiler chickens were randomly distributed into 16 experimental treatments resuIting from the combination of 4 levels of dietary PUFA (15, 34, 45, and 61 g/kg) and 4 levels of supplementation with alpha-TA (0, 100, 200, and 400 mg/kg). Thiobarbituric acid reactive substance (TBARS) values in cooked meat and cooked refrigerated meat were 12- and 24-fold higher, respectively, than in raw meat. Dietary polyunsaturation and alpha-TA supplementation affected lipid oxidation more markedly in cooked meat and cooked refrigerated meat than in raw meat and raw refrigerated meat. Lipid oxidation in cooked meat showed a significant linear increase as the concentration of PUFA in raw meat increased. The oxidative stability of meat was not affected by an increase in the dietary alpha-TA level from 200 to 400 mg/kg. Nonlinear relationship between TBARS values in cooked meat and alpha-tocopherol content of raw meat showed saturation in the antioxidant effect of alpha-Toc. The equation y = x (11.88 + 63.38e(-0.007z) was calculated to predict the minimum inclusion of alpha-tocopherol to diets (z) of chickens with certain dietary PUFA content (x) to assure a certain TBARS value (y).

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.

Cholesterol levels and sensory characteristics of meat from broilers consuming moderate to high levels of alfalfa

There is an urgent need in industrialized societies to develop novel products that can lower human dietary cholesterol intake. Dehydrated alfalfa is a good source of hypocholesterolemic compounds such as saponins. Whether consumption of alfalfa by chickens would decrease the cholesterol content of broiler meat remains, however, to be established. We determined meat quality characteristics, lipid and cholesterol contents, and consumer preference of broiler meat derived from production systems based on restricted feeding of a commercial diet combined with provision of free-choice dehydrated alfalfa. Results demonstrated that it was possible to produce chicken breast meat with reduced cholesterol content. In addition, total lipids in chicken meat were significantly decreased when a higher level of restriction was applied. Members of a 50-person consumer panel preferred meat from animals not consuming or consuming moderate levels of alfalfa. Those members that preferred meat from animals consuming the higher percentage of alfalfa identified taste as the primary attribute influencing that decision. Together the results suggest that it is possible to develop novel broiler production systems that will produce leaner meat that is acceptable to consumers and has a reduced cholesterol content.

Severity of Atherosclerosis in Parrots in Relation to the Intake of α-Linolenic Acid

Atherosclerosis is a common disease among parrots, but little is known about possible risk factors. Important risk factors in humans are an elevated plasma cholesterol concentration and increased platelet aggregation; high intakes of polyunsaturated fatty acids have beneficial effects. In this study, we tried to establish a relationship, if any, between dietary fatty acids and the severity of atherosclerosis in parrots. We collected dead parrots and scored the degree of atherosclerosis in the beginning of the aorta and the brachiocephalic arteries. It was not possible to assess the intake of fatty acids with food questionnaires so fatty acid composition of adipose tissue and breast muscle had to be used as an index of the dietary fatty acid composition. In all, 202 birds were collected. Gender was not related with atherosclerosis, but the degree of atherosclerosis increased with age and among the various species; African grey parrots appeared to be the most susceptible. The contents of linoleic acid in breast muscle or adipose tissue were not associated with the severity of atherosclerosis. For the relative percentage of alpha-linolenic acid in either breast muscle (P = 0.09; n = 175) or adipose tissue (P = 0.056; n = 21), a borderline significant relation with the degree of atherosclerosis was found. Parrots without atherosclerosis had significantly higher levels of alpha-linolenic acid than did the other animals. On the basis of these data, we suggest tentatively that a high dietary intake of alpha-linolenic acid protects against the development of atherosclerosis in parrots.

Chia seed (Salvia hispanica L.) as an omega-3 fatty acid source for broilers: influence on fatty acid composition, cholesterol and fat content of white and dark meats, growth performance, and sensory characteristics

Five thousand four hundred, 1-d-old, male, Ross 308, broiler chicks were fed for 49 d to compare diets containing 10 and 20% chia (Salvia hispanica L.) seed to a control diet. Cholesterol content, total fat content, and fatty acid composition of white and dark meats were determined at the end of the trial. A taste panel assessed meat flavor and preference. Cholesterol content was not significantly different among treatments; however, the 10% chia diet produced a lower fat content in the dark meat than did the control diet. Palmitic fatty acid content was less in both meat types when chia was fed, with differences being significant (P < 0.05), except for the white meat and the 20% chia diet. alpha-Linolenic fatty acid was significantly higher (P < 0.05) in the white and dark meats with the chia diets. Chia significantly lowered the saturated fatty acid content as well as the saturated:polyunsaturated fatty acid and omega-6:omega-3 ratios of the white and dark meats compared to the control diet. No significant differences in flavor or preference ratings were detected among diets. Body weight and feed conversion were significantly lower with the chia diets than with the control, with weight reductions up to 6.2% recorded with the 20% chia diet.

Alpha-tocopherol transfer efficiency and lipid oxidation in fresh and spray-dried eggs enriched with omega3-polyunsaturated fatty acids

We evaluated the effect of supplementing a basal diet containing 5% linseed oil with 0, 50, 100, and 200 mg/kg of alpha-tocopheryl acetate (alpha-TA) on alpha-tocopherol content, fatty acid composition, and lipid oxidation in fresh and spray-dried eggs during storage. Alpha-tocopherol transfer efficiency from feed to egg was also studied. The alpha-tocopherol content of fresh egg increased in a dose-dependent manner (16.6, 49.8, 78.9, and 132.3 microg/g of egg for 0, 50, 100, and 200 mg/kg alpha-TA supplementation, respectively), but transfer efficiency decreased, from 41.8% to 26.7%, with increasing alpha-tocopherol content in the diet. Spray-drying significantly decreased the alpha-tocopherol content of eggs and increased lipid oxidation. Dietary supplementation with different levels of alpha-TA significantly reduced lipid oxidation in spray-dried eggs. Alpha-TA supplementation had no significant effect on the fatty acid composition of fresh eggs.

n-3 enrichment of chicken meat. 1. Use of very long-chain fatty acids in chicken diets and their influence on meat quality: fish oil

We assessed the effect of a diet supplemented with fish oil (FO) on the performance, fatty acid (FA) composition, quality, and sensory traits of broiler meat. Diets enriched with 0, 2, or 4% FO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to the birds throughout a 38-d growth period. T3 was replaced by a mixture of FO, linseed oil (LO), and T (1, 3, and 4% respectively) for 1 wk (T4) or 2 wk (T5) before slaughter. Meat quality, taste, and FA profile were determined. Higher final weights were recorded for birds fed T3, although feed efficiency was not affected. Other performance or objective meat quality parameters did not show significant differences among treatments. High FO concentrations decreased the saturated and monoenoic FA contents in the thigh samples. The amount of polyunsaturated fatty acids (PUFA) increased when added to the diet (FO diets), mainly as long-chain n-3 FA [eicosapentaenoic fatty acid (EPA), docosapentaenoic fatty acid (DPA), and docosahexaenoic fatty acid (DHA)]. On the other hand, levels of total n-6 FA resulted in slight changes, mostly in linoleic acid (LA). By replacing the FO diet with the experimental mixture (T4, T5), the n-3 and n-6 FA contents increased, mainly in the form of linolenic acid and LA, respectively, only 1 wk later. After 1 wk of T4, the DHA levels in chicken decreased. Sensory panelists could not identify the meats from T4 and T5 as being different from the control diet (T1).

n-3 enrichment of chicken meat. 2. Use of precursors of long-chain polyunsaturated fatty acids: linseed oil

To assess the effect of supplying linseed oil (LO) in the diet on performance, fatty acid (FA) composition, and quality objective parameters of broiler meat, diets enriched with 0, 2, or 4% LO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to broiler chickens throughout a 38-d growth period. T3 birds were slaughtered at 24 or at 52 d of age to study the effect of feeding time on FA accumulation in tissue. Objective and subjective evaluations of meat quality were performed on samples from 38-d-old birds, and the FA profiles of thigh and liver samples were determined. Performance parameters showed little difference between treatments. The differences in carcass yield values or in the objective quality parameters of the meat between treatments were not significant. Increased levels of LO clearly decreased the saturated (SAT) and monounsaturated FA (MUFA) contents. LO increased the amount of polyunsaturated FA (PUFA), mainly because of the linolenic (LNA) and linoleic (LA) acid content in the T3 samples, but they hardly reflected the wide range given in the experimental diets. The n-3 long-chain (LC) PUFA content of T3 thighs was slightly higher than in T1 thighs. Unexpectedly, longer feeding time of LO diets did not result in peripheral tissue accumulation of n-3 LC-PUFA, although chickens could convert LNA to longer-chain metabolites in liver at 24 d of age.

Effect of dietary supplementation with rosemary extract and alpha-tocopheryl acetate on lipid oxidation in eggs enriched with omega3-fatty acids

The antioxidant effect of dietary supplementation with 500 or 1,000 mg/kg of a commercial rosemary extract vs. 200 mg/kg of alpha-tocopheryl acetate (alpha-TA) on the lipid oxidative stability of omega3-fatty acid (FA)-enriched eggs was compared. Lipid oxidation was measured in fresh eggs by the lipid hydroperoxide level and malonaldehyde content. Stability to iron-induced lipid oxidation was also measured. Results showed the clear antioxidant effect of dietary alpha-TA supplementation on omega3-FA enriched eggs. In contrast, dietary supplementation with rosemary extract showed no effect on any of the lipid oxidation parameters evaluated.

Dietary fatty acid profile modifies abdominal fat deposition in broiler chickens

An experiment was conducted to study the effect of different dietary fatty acid profiles on abdominal fat deposition in broilers. Diets with four types of fats (tallow, olive oil, sunflower oil, and linseed oil), at two levels of fat inclusion (either 6 or 10%), were administered to males from 21 to 42 d and to females from 21 to 49 d of age. The sexes were studied separately. Performance parameters, abdominal fat, muscle fat and cholesterol, and fatty acid profile of thigh, breast, and abdominal fat were determined. Broilers fed sunflower and linseed oils presented better values of feed efficiency. Abdominal fat and cholesterol content of thigh muscle were significantly lower in animals fed sunflower and linseed oils than in those fed tallow or olive oil (P < 0.001). In females, abdominal fat increased with level of fat inclusion only in birds fed tallow or olive oil, whereas it remained constant in birds fed sunflower or linseed oil. Muscle fat content was lower for birds fed tallow or olive oil but not significantly. The fatty acid profile of the different tissues reflected dietary fatty acid profile. Monounsaturated fatty acids were higher in abdominal fat, whereas polyunsaturated fatty acids were higher in muscle fat. These results suggest that polyunsaturated fatty acids produce lower abdominal fat deposition than saturated or monounsaturated fatty acids.

Incorporation of different polyunsaturated fatty acids into eggs

An experiment was carried out to examine thoroughly the relationships among different n-3 and n-6 polyunsaturated fatty acids (PUFA) in the diet, their deposition into the eggs' fat, and their effect on hens' laying performance. A diet enriched with 4% fish oil (FO) was fed to the birds throughout the 14-wk laying period (Treatment 1; T1); this was the same oil source that was replaced in proportions of 25, 50, 75, or 100% with four different fat sources, resulting in 17 isocaloric dietary treatments: linseed oil (LO; T2 to T5), rapeseed oil (RO; T6 to T9), sunflower oil (SO; T10 to T13), and tallow (T; T14 to T17). Performance parameters were recorded weekly and analyzed on the basis of the replacing fat source. At the end of the 14-wk experimental period, eggs were collected, and their fatty acid (FA) profile was determined. Performance parameters were not significantly different among grouped treatments. Smaller proportions of FO in diets resulted in lower values of saturated and higher values of n-6 FA contents, regardless of the fat source used when replacing FO. The n-6 content increased mostly because of the rise in linoleic acid (LA), although the level of arachidonic acid (AA) was always higher when FO was completely suppressed. The amount of the different n-3 long-chain PUFA was lower (P < 0.001) when FO was present in lesser proportions in the diet. However, the slope of the decline of these FA changed according to the included fat. Replacing FO with LO resulted in the lowest decline of its derivatives by elongation and desaturation and an increase in the total n-3 FA in the form of linolenic acid (LNA).