Fatty Acid Content Of Eggs Research Articles

Feeding Laying Hens a Diet Containing High-Oleic Peanuts or Oleic Acid Enriches Yolk Color and Beta-Carotene While Reducing the Saturated Fatty Acid Content in Eggs

We investigated the dietary effects of high-oleic peanuts (HOPN) or oleic fatty acids (OA) on older production hen performance, egg mass and quality, and lipid composition. A total of 99 laying hens were divided between three treatments and fed ad libitum for 8 weeks: (1) Conventional diet; (2) HOPN diet; (3) OA diet. Body weight (BW) was measured at weeks 1 and 8, and feed, egg weights (EW), and egg quality parameters were collected. Data was analyzed by analysis of variance at p < 0.05 significance level. There were no treatment differences in 8 week BW, feed conversion ratio, or average weekly egg quality parameters. The 8 week average EW of eggs from the HOPN group had reduced EW relative to the other treatment groups (p = 0.0004). The 8-week average yolk color score (p < 0.0001) was greater in eggs from the HOPN group relative to the other treatments. Overall, the β-carotene (p < 0.006) and OA content (p < 0.0001) was greater in eggs from the HOPN group, with reduced saturated fats in eggs from the HOPN group relative to the other treatments. These results suggest that HOPN and/or OA may be a useful layer feed ingredient to enrich eggs, while significantly reducing egg size in older production hens.

Risk of predation alters resource allocation in Daphnia under food limitation

AbstractLife-history theory predicts that animals adjust their resource allocation to somatic growth or to reproduction to maximize fitness. Resource allocation in Daphnia is known to respond to quantitative food limitation as well as to kairomones released from predators. Here we investigated in a full-factorial design how kairomone from larvae of Chaoborus flavicans, a gape-limited predator, and food quantity (0.5 mg C/L versus 1.5 mg C/L) affect the fatty acid allocation of D. pulex. Low food diminished somatic growth, clutch size and clutch biomass and increased neckteeth formation in response to the kairomone. Low food further led to increased fatty acid amounts per individual egg as well as to increased fatty acid content in eggs and to increased relative fatty acid allocation to reproduction. The latter effect was suppressed by kairomone of Chaoborus, whereas on high food the provision of eggs was further enhanced. We also found that more eicosapentaenoic acid was retained in the body of mothers in the presence of the predator at low food concentrations. These findings indicate that under food limitation and in the presence of kairomone from Chaoborus larvae, Daphnia switches from allocation into current reproduction to investment into future reproductive events.

تغذية الدواجن لغرض خاص: بيض المائدة أحماض أوميغا 3 الدهنية المتعددة غير المشبعة كغذاء وظيفي: مقالة مراجعة

في بداية القرن الحادي و العشرين تم إعتبار علم تغذية الإنسان وسيلة لتحسين نوعية الحياة و الصحة العامة. دور الغذاء في صحة الإنسان و وعي المستهلكين للأغذية الصحية وجه البحوث نحو انتاج أغذية لها آثار صحية محددة على الوقاية من الأمراض و علاجها. هذه الأغذية أثبتت بشكل مرض أثرها المفيد على واحد أو أكثر من وظائف الجسم، بجانب توفير التغذية الكافية. تسمى هذه الأغذية بالأغذية الوظيفية. إنتاج بيض المائدة الغني بالأحماض الدهنية غير المشبعة أوميغا-3 كغذاء وظيفي هو نموذج جديد في تغذية الدواجن. قدرة الحيوانات وحيدة المعدة على ترسيب الأحماض الدهنية في أنسجتها دون التأثير على القيمة الحسية لهذه المنتجات يعتبر حجر الأساس و نقطة البداية لإنتاج بيض أوميغا-3. الأدبيات المختصة بهذا الموضوع وضعت أساسا قويا لإنتاج هذا النوع من الأغذية الوظيفية. المصادر الغذائية للأحماض الدهنية غير المشبعة المستخدمة في تغذية الدجاج البياض عدلت محتوى هذه الأحماض في صفار البيض مما جعل البيض المنتج مناسبا لتقديمه كغذاء وظيفي. ويمكن زيادة محتوى صفار البيض من هذه الأحماض عن طريق إضافة مصادر علفية غنية بألفا لينولينك مثل بذر الكتان أو غنية ب DHA و EPA مثل زيت السمك و مسحوق السمك.

Performance and egg quality of laying hens fed flaxseed: highlights on n-3 fatty acids, cholesterol, lignans and isoflavones

Flaxseed is a rich source of α-linolenic acid and phytoestrogens, mainly lignans, whose metabolites (enterodiol and enterolactone) can affect estrogen functions. The present study evaluated the influence of dietary flaxseed supplementation on reproductive performance and egg characteristics (fatty acids, cholesterol, lignans and isoflavones) of 40 Hy-Line hens (20/group) fed for 23 weeks a control diet or the same diet supplemented with 10% of extruded flaxseed. The flaxseed diet had approximately three times the content of lignans (2608.54 ng/g) as the control diet, mainly secoisolariciresinol diglucoside (1534.24 v. 494.72 ng/g). When compared with the control group, hens fed flaxseed showed a similar deposition rate (72.0% v. 73.9%) and egg yield. Furthermore, there was no effect of flaxseed on the main chemical composition of the egg and on its cholesterol content. Estradiol was higher in the plasma of the control group (1419.00 v. 1077.01 pg/ml) probably due to the effect of flaxseed on phytoestrogen metabolites. The plasma lignans were higher in hens fed flaxseed, whereas isoflavones were lower, mainly due to the lower equol value (50.52 v. 71.01 ng/ml). A similar trend was shown in eggs: the flaxseed group had higher level of enterodiol and enterolactone, whereas the equol was lower (198.31 v. 142.02 ng/g yolk). Secoisolariciresinol was the main lignan in eggs of the flaxseed group and its concentration was three times higher then control eggs. Flaxseed also improved the n-3 long-chain polyunsaturated fatty acids of eggs (3.25 v. 0.92 mg/g egg), mainly DHA, however, its oxidative status (thiobarbituric reactive substances) was negatively affected. In conclusion, 10% dietary flaxseed did not affect the productive performance of hens or the yolk cholesterol concentration, whereas the lignans and n-3 polyunsaturated fatty acid content of eggs improved. Further details on the competition between the different dietary phytoestrogens and their metabolites (estrogen, equol, enterodiol and enterolactone) should be investigated.

Is it possible to increase the n-3 fatty acid content of eggs without affecting their technological and/or sensorial quality and the laying performance of hens?

The aim of this study was to increase the n-3 fatty acid (n-3 FA) content of eggs without affecting their sensorial and/or technological properties or the laying performance of hens. Laying hens from line 477 were divided into 5 groups corresponding to 5 different diets over the laying period: control diet (C) and diets containing extruded linseed with a high level of fibre (ELHF), extruded linseed with a low level of fibre (ELLF), microalgae, or a combination of 75% ELLF and 25% MA (ELLF+MA).Dietary enrichment with n-3 FA had no effect on the laying performance, hen body weight or egg white viscosity. The egg yolks produced by hens fed the diet containing microalgae were redder than egg yolks from the other groups, suggesting the presence of red pigments in the microalgae preparation. However, the colour difference was low and not perceptible to the human eye. Moreover, colour measurement of egg yolks by sensorial analysis panellists using the Roche colour fan did not reveal a diet effect on this parameter.Egg yolk lipid content was not affected by diet. The egg yolk of hens fed on diets containing linseed and/or microalgae had greater n-3 FA content (×2.5 to 2.9 compared to group C). Linseed mainly increased the linolenic acid content (×3.0 to 3.4 compared to group C) and the microalgae increased the LC n-3 FA content (×4.1 compared to group C). Dietary enrichment with n-3 FA had no effect on the sensorial quality of shell cooked eggs except for the “unusual flavour” criterion for which the score was higher for the MA group compared to the other groups and corresponded to a fishy flavour.

Effect of hempseed (Cannabis sativa L.) on performance, egg traits and blood biochemical parameters and antioxidant activity in laying Japanese Quail (Coturnix coturnix japonica)

1. This study was conducted to determine the effects of hempseed (HS) on performance, egg traits, serum lipid profile and antioxidant activity in Japanese quail (Coturnix coturnix japonica).2. A total of 120 eight-week-old laying quail were divided into 4 experimental groups with 10 replicates. The treatments were as follows: (1) control diet (C, no HS in the diet); (2) 5% HS in the diet (HS5); (3) 10% HS in the diet (HS10); and (4) 20% HS in the diet (HS20). The quail were fed the experimental diets from 8 to 14 weeks of age.3. There was no significant difference in body weight, feed intake and feed conversion ratio of the birds overall in the experiment. The egg production was not influenced by the HS contents in the diet; however the HS10 diet increased egg weight and egg-specific gravity. The carcass traits were not affected by the HS contents.4. The serum triglyceride, cholesterol and the high density lipoprotein were not significantly altered; however, low density lipoprotein (LDL) concentration in HS-supplemented groups were lower than that of the C group.5. The malondialdehyde, superoxide dismutase, catalase and nitrogen oxide concentrations were not significantly affected, but in the HS10 and HS20, glutathione peroxidase (GSH-Px) concentration was higher than in the C and HS5 groups.6. The omega-3 fatty acid content of eggs increased linearly with increasing dietary HS content in the diet.7. In conclusion, HS could be a potential feed and health benefit as a natural antioxidant in relation to decreasing serum LDL and increasing GSH-Px concentration in the liver of laying quail.

Effect of Time and Fatty Acid Composition in Eggs of White Leghorn Hens Supplemented with Tuna Oil

The study evaluated the effect of time and fatty acid (FA) composition in eggs of laying hens supplemented with tuna oil (TO). Two hundred White Leghorn hens 30-week were divided into 5 treatments with 4 replicates of 10 birds each. Treatments were assigned randomly and consisted of 0%, 0.75%, 1.50%, 2.25% and 3% TO in commercial sorghum-soybean meal diets, in which the soybean oil was partially replaced. The experiment was conducted for 90 days. At days 28, 56 and 84 of the experiment, 10 eggs per replicate were collected for chemical analysis. Feed intake, egg production rate, egg weight, and feed conversion were not influenced by dietary treatment. FA content was significantly altered (P < 0.05) by TO, showing a progressive increase in egg n-3 FA (especially docosahexaenoic [DHA] and eicosapentaenoic [EPA] acids) when TO was added. Levels of EPA and DHA were higher (P < 0.05) in the egg lipids of TO fed hens than those in the control group. This was correlated (P < 0.05) with the concentration of TO in the diet. However, no significant differences were observed either in egg weight or percent of egg lay between groups. There was a high correlation (P < 0.05) between TO inclusion level in the diet and the incorporation of EPA (r = 0.96) or DHA (r = 0.92) into the egg yolk and an overall decrease in n-6 FA. There was a high correlation (P < 0.05) between TO inclusion level and the incorporation of linoleic acid (LA, r = －0.95) or arachidonic acid (AA, r = －0.96) into the egg yolk. The highest incorporation (P < 0.05) of total n-3 FA content in eggs was obtained with 3% TO/kg. This increase was proportional to TO inclusion levels in the diets (r = 0.95). The results indicate that the n-3 FA content in eggs can be increased by dietary supplementation with TO, and that TO can serve as a reasonable alternative feed ingredient in layer diets to produce a healthier choice of egg.

Effects of graded replacement of soybean meal by sunflower seed meal in laying hen diets on hen performance, egg quality, egg fatty acid composition, and cholesterol content

SUMMARY Protein feed sources are becoming more and more limited worldwide. Soybean meal, as the primary and most reliable protein source, is becoming increasingly expensive; therefore, there is a need to look for economic alternative protein sources. This trial was conducted to evaluate the effects of graded replacement of soybean meal by sunflower seed meal (SSM) on the performance, egg quality, egg fatty acid composition, and cholesterol content in Rugao laying hens (a local breed). One hundred sixty 28-wk-old laying hens were randomly assigned to 4 groups of 40 birds. Each group was made up of 4 replicate subgroups, with 10 laying hens each. All birds were acclimated to the basal diet for 1 wk. Experimental diets contained 0 (control), 8.26, 16.52, and 24.84% SSM (ME, 8.50 MJ/kg; CP, 33.00%; Ca, 0.26%; P, 1.03%) replacing soybean meal. Feed and water were offered ad libitum for 6 wk. No significant difference (P > 0.05) was observed among treatments in the performance and egg quality of laying hens. The concentrations of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in yolks were consistent among the diets, except that the percentage of C17:0 decreased in the yolks of birds fed the experimental diets (P < 0.05). However, after 6 wk of feeding, the egg yolk cholesterol concentrations of birds in the experimental groups were lower than those of birds in the control group (P < 0.05). Thus, it could be feasible to use SSM in laying hen diets as an available ingredient replacing soybean meal, without affecting performance or egg fatty acid content while reducing the cholesterol level in the yolk and the production cost.

Effect of feeding hemp seed and hemp seed oil on laying hen performance and egg yolk fatty acid content: Evidence of their safety and efficacy for laying hen diets

Forty-eight 19-wk-old Bovan White laying hens were fed 1 of 5 diets containing either hemp seed (HS) or hemp seed oil (HO). The level of HO was 4, 8, or 12%, whereas the level was 10 or 20% for the HS. A set of 8 birds fed wheat-, barley-, and corn oil-based diets served as the control. Performance was monitored over 12 wk. Average hen-day egg production was not affected upon feeding of either HS or HO diets. Egg weight was higher than that of the controls for hens consuming the 20% HS diet (P < 0.05). Feed intake was lower than that of the controls for birds consuming the 4% HO diet but similar across other treatments. Final BW were not affected by diet, with the exception of being lower than that of the controls (P < 0.05) in hens consuming the 12% HO diet. The total egg yolk n-3 fatty acid content increased linearly (P < 0.05) with increasing dietary α-linolenic acid provision with the HS- or HO-based diets. A quadratic response (P < 0.05) was observed for docosahexaenoic acid levels in egg yolk in response to increasing dietary α-linolenic acid supply. The expression of hepatic fatty acid desaturase 1 and 2, key genes for the desaturation of long-chain polyunsaturated fatty acids, was significantly decreased (50–60% of controls; P < 0.05) as a result of feeding HS or HO diets. Based on the results from the current study, the inclusion of the hemp products HS or HO in the diets of laying hens up to a maximum level of 20 and 12%, respectively, does not adversely effect the performance of laying hens and leads to the enrichment of the n-3 fatty acid content of eggs.

N-3 Fatty acid content in eggs laid by hens fed with marine algae and sardine oil and stored at different times and temperatures

Inclusion of sardine oil (SO) in diets for laying hens significantly increases the n-3 polyunsaturated fatty acids (PUFAs) in the egg, but these are more sensitive to oxidation, so the storage time and temperature can cause a decrease in their concentration. Therefore, the objective of this study was to determine the effect of algae Macrocystis pyrifera, Enteromorpha spp., and Sargassum sinicola on n-3 PUFA contents in eggs from laying hens fed diets supplemented with sardine oil and stored for different times (0, 15, and 30 days) and temperatures (20°C and 4°C), for 8 weeks. One hundred and twenty hens were divided into four treatments: T1 (commercial diet), T2 (2% SO + 10% M. pyrifera), T3 (2% SO + 10% Enteromorpha), and T4 (2% SO + 10% S. sinicola). At the end, 50 eggs per treatment were collected to quantify total lipids and egg n-3 PUFAs at different times (0, 15, and 30 days) and temperatures (20°C and 4°C) of storage. The results were analyzed using a 3 × 3 × 2 factorial design, and Tukey test to compare means (P < 0.05). The results show that M. pyrifera and S. sinicola had a better effect on eicosapentaenoic acid, while Enteromorpha was better for docosahexaenoic acid. In relation to time and temperature, the content of the fractions analyzed in the three treatments at 15 days/4°C had a lower loss compared with eggs analyzed at day 0/20°C.

Fatty acid content of eggs determines antipredator performance of fish larvae

Recent work has suggested that provisioning of eggs with certain critical nutrients could be a more meaningful measure of maternal investment and correlate of offspring fitness than traditional measures of egg size. The aim of our study was to assess variability in egg quality and larva quality and to identify connections between them and the implications for larval survival. Egg size, proximate composition, and fatty acid composition were measured for 40 batches of eggs from 8 captive pairs of red drum (Osteichthyes: Sciaenops ocellatus). We reared larvae from these batches of eggs to a common size (10mm total length, 2–3weeks posthatching) and assessed routine activity and escape response performance of 671 individuals. Egg fatty acid composition varied more than egg size or proximate composition. Concentrations of certain long chain, highly unsaturated essential fatty acids (e.g., arachidonic acid and docosahexaenoic acid) were the only egg traits that were significantly related to larva quality (measured as escape performance). Reduced escape performance of larvae from eggs with low fatty acid concentrations was not compensated by 3weeks of feeding on a diet enriched with fatty acids, suggesting irreversible developmental effects. Since fatty acids in eggs originate from the maternal diet, offspring survival may be determined in part by availability of nutrient-rich prey to pre-spawning adults. Migrations, regime shifts, and exploitation of marine communities could operate through this mechanism to influence recruitment in fish populations. Our findings underscore the importance of non-genetic maternal contributions to egg quality and the linkage between environmental conditions experienced by adult females and offspring fitness.

Essential fatty acid content of eggs and performance of Layer Hens fed with different levels of full-fat flaxseed

An examination of the earlier studies in the USA and Canada demonstrate that flax seeds are good source of omega 3 fatty acids. This experiment studies the effect of providing laying hens, with various levels of roasted and unroasted locally produced flax seeds. A key components of this experiment involved attentively observing the laying hens performance, and determining the fatty acids content of the eggs produced. Five levels of flax seeds 0, 5, 10, 15 and 20 dry weight %, roasted or unroasted, were fed to 200 pullets in 5 replicates (4 birds/cage). The results indicated that feeding 5 or 10% roasted flax seed supported good egg production. Birds fed higher levels of unroasted flax seed had the lowest feed consumption. Livability, egg weight, yolk color and specific gravity values were not significantly affected by feeding flax seeds. Feeding 15% unroasted flax seeds maintained higher omega-3 levels: that is docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and alpha-linolenic acid (C18:3n3) levels in egg, whereas feeding 5 or 15 weight % unroasted flax seeds resulted in the highest level of linoleic acid (C18:2n6) in the egg. Roasting the seeds did not improve the omega-3 content of the egg. Feeding flax, regardless of heat treatment, marginally increased the amount of cholesterol. The saturate palmitic acid (C16:0) was lower at 15% flax inclusion. We conclude that 10% flax seed added to feed supports good egg production. However, 15% inclusion of unroasted flax may relatively lower the egg production rate but would support an excellent profile of omega 3 fatty acids in the egg. Key words: Docosahexaenoic acid, eicosapentaenoic acid, docosapentaenoic acid, α-linolenic acid, production, flax seeds.

Fatty acid profile and sensory characteristics of table eggs from laying hens fed diets containing microencapsulated fish oil

The present work investigated the effect of a fish oil derived source of n-3 fatty acids in microencapsulated form on the following: (1) DHA and EPA transfer to table eggs, and (2) the sensory attributes of the eggs prepared using two methods. Ninety-six individually caged Single-Comb White Leghorn laying hens were randomly divided into 4 groups and each group fed 1 of 4 treatment diets containing 0, 20, 40, or 60 g/kg diet of microencapsulated fish oil (MFO) product. Diets were offered for 21 days, and eggs sampled for lipid and sensory analysis for the final 3 days. Total n-3 fatty acid content differed ( P<0.05) between treatments, increasing from 141 mg/total yolk (0 g MFO/kg diet) to 299 mg/total yolk (60 g MFO/kg diet). Sensory attribute differences between treatments appeared to be dependent on preparation method. Significant differences ( P<0.05) between treatments were found for hard-boiled samples for “sulphur-odour,” “aftertaste-flavour,” “off-flavour” and “sulphur-flavour.” No significant ( P>0.05) sensory differences between treatments were found for scrambled egg samples. Boiled egg samples from the 60 g MFO/kg diet treatment had significantly ( P<0.001) higher “off-flavour” and “sulphur-flavour.” The results provide evidence that the use of microencapsulated fish oil can serve as an effective vehicle for increasing total long chain n-3 fatty acid content of eggs, but the potential for some adverse sensory attributes is present at the higher levels of incorporation.

Evidence for conjugated linoleic acid-induced embryonic mortality that is independent of egg storage conditions and changes in egg relative fatty acids

Three experiments were performed to determine the effect of conjugated linoleic acid (CLA) on embryonic development in the absence of vitelline membrane disruption. In experiment 1, when eggs from control and CLA (0.5%)-fed hens were stored at 21 or 15°C for 48 h, mineral movement between the yolk and albumen was not observed (with the exception of Mg and Na). Also, it was found that CLA-induced changes in yolk fatty acid content (e.g., increased saturated fatty acids and CLA) had begun to change after 5 d of feeding hens CLA, and no differences were detected in fatty acid composition after 14 d. In experiment 2, the hatchability of eggs incubated directly after oviposition or stored 24 h at 21 or 15°C was determined from hens fed control or 0.5% CLA diets. Regardless of storage conditions, CLA reduced hatchability. These data showed that CLA elicits negative effects on hatchability independent of vitelline membrane disruption or egg storage condition. In experiment 3, eggs were collected from hens fed 0 or 1% CLA daily for 3 wk, stored at 21°C for 24 h, and incubated. Not only did CLA decrease hatchability, the data showed as the days of CLA feeding increased, the days of survival during incubation decreased. Average days of embryonic survival during incubation for the CLA group diminished to 18.0, 13.4, and 6.3 d for wk 1, 2, and 3 of CLA feeding, respectively, and control remained at 20.6, 20.8, and 19.8 for the 3 wk. These studies suggested that without the disruption of the vitelline membrane, hatchability and embryonic days of survival were significantly reduced by maternal CLA feeding in comparison to control-fed hens. Evidence that embryos die earlier the longer the hens are fed CLA, even though no additional changes in the fatty acid content of eggs were found, suggested that factors other than storage and egg yolk fatty acid composition played a role in CLA-induced embryonic mortality.

Modifying egg fatty acid content by supplementation of laying hen diets with palm olein oil (POO)

Palm oil is the most abundant of all oils produced globally. It is very high in saturated fatty acids specifically palmitic acid, but other fatty acids (monounsaturated (MUFA) and polyunsaturated) are presented at low concentrations. In the processing plant some high amount of oleic acid with some other unsaturated fatty acids are extracted and marketed as Palm olein oil, and used to reduce blood or egg cholesterol (Rievelles et al., 1994). The objective of this study was to determine the optimum level of dietary palm olein oil required to enrich the mono-unsaturated fatty acid content of yolk, egg cholesterol and antibody titre.

Cholesterol and n-3 and n-6 fatty acid content in eggs from laying hens fed with red crab meal (Pleuroncodes planipes)

Red crab (Pleuroncodes planipes) is a marine crustacean that represents an abundant resource that has not been properly used. The aim of this study was to evaluate the effects on cholesterol and n-3 and n-6 FA content in eggs when red crab meal (RCM) was included in laying hen rations. Ninety White Leghorn laying hens were randomly distributed into 3 treatments: control (0%RCM), 3% red crab meal (3%RCM), and 6% red crab meal (6%RCM) for 3 wk. Cholesterol and linoleic (LA), alpha-linolenic (ALA), arachidonic (AA), eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids were analyzed by gas chromatography. Performance parameters and cholesterol content were not different among treatments (P > 0.05). Total lipids were different in the control group and 6%RCM (9.0 and 9.4% respectively) compared with 3%RCM (10.9%). With 3%RCM and 6%RCM, the levels of all fatty acids analyzed were higher than in the control. Diets with 3 and 6% RCM doubled the content of ALA (16.4 and 15.4 mg/100 g of egg, respectively). Eicosapentaenoic acid was lowest in 0%RCM (6 mg/100 g of egg) compared with 3%RCM (13 mg/100 g) and 6%RCM (17 mg/100 g). Similar results were obtained for DHA (56, 133, and 246 mg/100 g of egg). Linoleic acid and AA were highest (1,211 and 228 mg/100 g, respectively) with 3%RCM and with 6%RCM (1,151 and 200 mg/100 g, respectively) vs. control (890 and 163 mg/100 g). The ratio of n-6 to n-3 FA was 3 times lower with 6%RCM than in the control. It was concluded that inclusion of red crab meal in laying hen rations at levels of 3 and 6% (P < 0.05) increased the n-3 and n-6 fatty acids content in eggs.

Fatty Acid Composition and Egg Components of Specialty Eggs

Egg components, total fat, and fatty acid content of specialty eggs were compared. One dozen eggs were collected and analyzed from each of five different brands from hens fed a diet free of animal fat (SP1), certified organic free-range brown eggs (SP2), uncaged unmedicated brown eggs (SP3), cage-free vegetarian diet brown eggs (SP4), or naturally nested uncaged (SP5). Regular white-shelled eggs were the control. A significant (P < 0.05) difference was observed in the egg components and fatty acid content in different brands. The percentage of yolk was lower (P < 0.05) in SP2 and SP4 with a concomitant increase (P < 0.05) in the percentage of white. The percentage of shell was lower (P < 0.05) in SP4 and SP5. The total edible portion was greater in SP4 and SP5. The yolk:white ratio was greater (P < 0.05) in SP3. The total lipid content was lower in SP4 eggs. The content of palmitic (C16:0), stearic (C18:0), and total saturated fatty acids were lower (P < 0.05) in SP1. No difference was observed in the content of palmitoleic (C16:1), oleic (C18:1), or total monounsaturated fatty acids. The content of n-3 fatty acids in SP2, SP4, and SP5 were similar to control eggs. The ratio of total n-6:n-3 polyunsaturated fatty acids ranged from 39.2 for SP5 to 11.5 for SP1 (P < 0.05). No difference was observed in the total polyunsaturated fatty acid content of eggs (P > 0.05).

Fatty acid composition of eggs enriched with omega –3 fatty acids on the market

The aim of our work was to determine fatty acid content in eggs enriched with omega-3 polyunsaturated fatty acids from various producers on the market. Due to simplicity, speed and reduced organic solvent usage, we used the in situ trans-esterification ISTE method for the determination of the fatty acid composition in eggs. The method was checked by the analysis of certified reference material CRM 164 (Anhydrous Milk Fat). The analytical results are in good accordance with certified values. The obtained results show that enriched eggs have a better fatty acid composition than average table eggs, regardless the producer. The ratio of FAs w -6 to w -3 in enriched eggs is less than 5, being 10 in ordinary eggs. An approximately equal content of alpha linolenic acid (18:3, n-3) was found in the enriched eggs from Jata Reja and Maia, 1.29 wt % and 1.25 wt % respect., while it was 11.28 wt % in the Fisher-Weppler’s eggs. The comparison of obtained results, the fatty acid content per 100 g egg content, with literature data is quite difficult, because authors calculate the content of FA in various ways. According to recent data from the literature (Weihrauch et al., 1977, Guardiola et al., 1994, Fatty acids, 1998, Kunachowicz et al., 1998), we have chosen a conversion factor of 0.83 in order to calculate the total fatty acids content in a 100 g egg content. The producers should declare the fatty acid composition, i.e. the content of w -3 PUFA-s, EPA and DHA on the package so that consumers are informed about the nutritional value of the food.

Maximizing lobster, Homarus gammarus (L.), egg and larval viability

The viability of batches of larvae reared to produce lobsters, Homarus gammarus (L.), for stock-supplementation experiments varied widely and rendered the timing and numbers of juveniles available for release unpredictable. Egg lipid reserves, time of hatching, exposure to low salinity during incubation and the influence of feeding regimes on water quality during larval culture were among the factors judged most likely to have affected viability. There was considerable variation in the lipid content of eggs from different females captured in 1989 and 1990. The proportion of lipid in eggs from females caught in 1990 was higher (10-20%) than that in eggs from females caught in 1989 (6-11%). The fatty acid content of eggs declined 72-80% during development although the overall proportions of fatty acids remained similar. Analysis of eggs and larvae from a single brood showed that rapidly developing eggs and the larvae that hatched from them contained greater triacylglyceride lipid reserves (by 49% and 15% respectively) than those which developed more slowly and hatched later. Exposure to reduced salinity (below 29 psu) prolonged development (by 30%), increased losses (to > 50%) and reduced the ratio of n-3:n-6 fatty acids (from 35-48 to 18-29) of eggs being incubated by captive, wild-caught, female lobsters. Larvae hatching from eggs held in reduced salinity (23 psu) survived less well (3% compared with 15%) than those incubated in sea water of 29 psu. The rate and degree to which fouling organisms became attached to larvae was related to feeding regime but not to development rate. A diet of mysids supplemented with mussel produced most fouling, generally poorer growth and a higher incidence of moulting abnormalities than a diet of mysids supplemented with Artemia nauplii. Among larvae fed Artemia, those developing early were significantly larger at instar 4 than late developers (56.4 mg cf. 49.8 mg, P < 0.05), but such differences in weight were not maintained by juveniles during the following 31 days of culture. The ecological and aquacultural implications of the results are discussed.

Effect of Feeding Full Fat Flax and Canola Seeds to Laying Hens on the Fatty Acid Composition of Eggs, Embryos, and Newly Hatched Chicks

Single Comb White Leghorn laying hens were fed diets containing 8 and 16% ground flax seed or 16% ground canola seed and were compared with birds fed a wheat and soybean control diet. Levels of omega-3 fatty acids in the egg yolk were monitored, and fertilized eggs were incubated after a plateau of omega-3 fatty acid level was reached. Fatty acid analyses were conducted on brain tissues of embryos at 15, 17, and 19 days of incubation and on newly hatched chicks. Fatty acid composition of plasma of the chicks was also determined. As compared with the controls, the omega-3 fatty acid content of eggs from hens fed flax and canola seed increased significantly (P<.05), and the brain tissue of embryos and chicks contained significantly (P<.05) more omega-3 fatty acids, predominantly docosahexaenoic acid (C22:6ω3). The plasma of the chicks from hens fed flax seed contained significantly (P<.05) more omega-3 fatty acids than those fed the control diet. The arachidonic acid (C20:4ω6) content in the egg yolk and chick plasma lipids from the flax fed laying hens were significantly reduced. The present study demonstrates that the omega-3 fatty acid content of eggs, embryos, and chicks can be enriched by feeding oil seeds to laying hens.