• Applied Microscopy
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• v.30 no.4
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• pp.367-376
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• 2000

The observation using an electron microscope shows that the maturation of the oocyte of African giant snail, Achatina fulica, proceeds over three stages. The oocyte of stage 1 is a small elliptic cell $(220\times400{\mu}m)$ whose light nucleoplasm contains two nucleoli. In its cytoplasm, a number of mitochondria, rough endoplasmic reticula, and ribosomes are found, while yolk granules are not. The nucleus of the oocyte of stage 2 is relatively large in comparison with the volume of cytoplasm, and contains one nucleolus. In the nuclear envelope comprising inner and outer double membrane, there are found a lot of nuclear pores for materials to pass through. A number of mitochondria, Golgi complex and lipid yolk granules appears in the cytoplasm, and proteinous yolk granules begin to form and mature in the vacuoles of various sizes ($0.8\sim3.0{\mu}m$ in diameter). The oocyte of stage 3 has an enlarged nucleolus. Material transportation through nuclear pore is not found any longer. The cytoplasm in this stage is filled with proteinous and lipid yolk granules. The microvilli are developed around the egg plasma membrane.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.1-25
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• 1996

The pathogenesis of atherosclerosis can not be summarized as a single process. Lipid infiltration hypothesis and endothelial injury hypothesis have been proposed and investigated. Recent developments show that there are many points of potential interactions between them and that they can actually be regarded as two phases of a single, unifying hypothesis. Among the many risk factors of atherosclerosis, plasma homocysteine and lipoprotein(a) draw a considerable interest because they are independent indicators of atherogenicity. Triglyceride (TG)-rich lipoproteins (chylomicron and VLDL) are not considered to be atherogenic but they are related to the metabolism of HDL cholesterol and indirectly related to coronary heart disease (CHD). LDL can of itself be atherogenic but the oxidative products of this lipoprotein are more detrimental. HDL cholesterol has been considered to be a favorable cholesterol. The so-called 'causalist view' claims that HDL traps excess cholesterol from cellular membranes and transfers it to TG-rich lipoproteins that are subsequently removed by hepatic receptors. In the so-called 'noncausalist view', HDL does not interfere directly with cholesterol deposition in the arterial wall but instead reflects he metabolism of TG-rich lipoproteins and their conversion to atherogenic remnants. Approximately 70-80% of the human population shows an effective feedback control mechanism in cholesterol homeostasis. Type of dietary fat has a significant effect on the lipoprotein cholesterol metabolism and atherosclerosis. Generally, saturated fatty acids elevate and PUFA lower serum cholesterol, whereas MUFA have no specific effect. EPA and DHA inhibit the synthesis of TG, VLDL and LDL, and may have favourable effects on some of the risk factors. Phospholipids, particularly lecithin, have an antiatherosclerotic effect. Essential phospholipids (EPL) may enhance the formation of polyunsaturated cholesteryl ester (CE) which is less sclerotic and more easily dispersed via enhanced hydrolysis of CE in the arterial wall. Also, neutral fecal steroid elimination may be enhanced and cholesterol absorption reduced following EPL treatment. Antioxidants protect lipoproteins from oxidation, and cells from the injury of toxic, oxidized LDL. The rationale for lowering of serum cholesterol is the strong association between elevation of plasma or serum cholesterol and CHD. Cholesterol-lowing, especially LDL cholesterol, to the target level could be achieved using diet and combination of drug therapy. Information on the link between cholesterol and CHD has decreased egg consumption by 16-25%. Some clinical studies have indicated that dietary cholesterol and egg have a significant hypercholesterolemic effect, while others have indicated no effect. These studies differed in the use of purified cholesterol or cholesterol in eggs, in the range of baseline and challenge cholesterol levels, in the quality and quantity of concomitant dietary fat, in the study population demographics and initial serum cholesterol levels, and clinical settings. Cholesterol content of eggs varies to a certain extent depending on the age, breed and diet of hens. However, egg yolk cholesterol level is very resistant to change because of the particular mechanism involved in yolk formation. Egg yolk contains a factor of factors responsible for accelerated cholesterol metabolism and excretion compared with crystalline cholesterol. One of these factors could be egg lecithin. Egg lecithin may not be as effective as soybean lecithin in lowering serum cholesterol level due probably to the differences of fatty acid composition. However, egg lecithin may have positive effects in hypercholesterolemia by increasing serum HDL level and excretion of fecal cholesterol. The association of serum cholesterol with egg consumption has been widely studied. When the basal or control diet contained little or no cholesterol, consumption of 1 or 2 eggs daily increased the concentration of plasma cholesterol, whereas that of the normolipemic persons on a normal diet was not significantly influenced by consuming 2 to 3 eggs daily. At higher levels of egg consumption, the concentration of HDL tends to increase as well as LDL. There exist hyper-and hypo-responders to dietary (egg) cholesterol. Identifying individuals in both categories would be useful from the point of view of nutrition guidelines. Dietary modification of fatty acid composition has been pursued as a viable method of modifying fat composition of eggs and adding value to eggs. In many cases beneficial effects of PUFA enriched eggs have been demonstrated. Generally, consumption of n-3 fatty acids enriched eggs lowered the concentration of plasma TG and total cholesterol compared to the consumption of regular eggs. Due to the highly oxidative nature of PUFA, stability of this fat is essential. The implication of hepatic lipid accumulation which was observed in hens fed on fish oils should be explored. Nutritional manipulations, such as supplementation with iodine, inhibitors of cholesterol biosynthesis, garlic products, amino acids and high fibre ingredients, have met a limited success in lowering egg cholesterol.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.157-163
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• 2007

To examine the effects of dietary organic selenium and vitamin E supplementation on egg production, egg weight, daily egg mass, feed intake, feed conversion, egg quality, lipid-soluble antioxidative capacity (ACL) in egg yolk, and selenium retention of egg in laying hens, Hy-Line laying hens of 77 wk old were replaced in the individual cage for 12 week. A corn-soybean meal based diet was supplemented with 0 (control), vitamin E 100 IU/kg and the combination of 0.9 ppm Se from selenium yeast (SY) and vitamin E 50, 100 and 150 IU/kg. Egg production and daily egg mass were significantly increased (P<0.05) in supplemental vitamin E 100 IU, and 0.9 ppm SY + vitamin E 50 IU than control for the whole experimental period. However, feed intake and feed conversion were not affected by supplemental vitamin E and SY. Haugh unit was significantly (P<0.05) higher in supplemental vitamin E 100 IU and 0.9 ppm SY + vitamin E 50 IU than control, 0.9 ppm SY + vitamin E 100 and 0.9 ppm SY + 150 IU in week 5. Haugh unit of the eggs during storage decreased significantly(P<0.05) from day 1 to day 11. However, Haugh units of the eggs from 0.9 ppm SY + vitamin E 150 IU treated groups did not decreased significantly until day 5. Yolk color was significantly (P<0.05) higher in 0.9 ppm SY + vitamin E 50 and 0.9 ppm SY + 100 IU than other treatment groups in week 1. Selenium concentrations of egg were significantly increased (P<0.05) in 0.9 ppm SY + vitamin E than control and vitamin E 100 IU groups. Lipid-soluble antioxidative capacity (ACL) in egg yolk was significantly (P<0.05) higher in supplemental combination of 0.9 ppm SY + vitamin E 150 IU when compared to those of other treatment groups.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.209-216
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• 2007

The ovarian structure and ultrastructural changes in germ cells during oogenesis of the spiny top shell, Batillus cornutus, have been investigated by light and electron microscopic observations. Specimens of the spiny top shell were collected from the subtidal zone of Wando, south coast of Korea. Spiny top shell was dioecious. The ovary was located on the surface of the hepatopancreas in the spiral posterior region. The ovary had greenish color in the gonadal mature season. The ovary comprised many ovarian lobules, and the ovarian lobule consisted of connective mesenchymal tissue and epithelial cells. Oogonium had a large nucleus with nucleolus of high electron density. In previtellogenic oocyte, small yolk granules of low electron density were scattered in the cytoplasm. Oocytes in the initial vitellogenic stage were connected with the ovarian lobule by egg stalk. The result of TEM observations showed that initial vitellogenic oocyte contained well-developed Golgi complex, endoplasmic reticula, tubular mitochondria and numerous yolk granules of various electron densities and sizes. The electron density, size and quantity of yolk granules which were distributed in the active vitellogenic oocyte were increased compared to the previous stage. Thickness of egg envelope in the late active vitellogenic oocyte was approximately 4.4 $[\mu}m$. Cytoplasm of ripe oocyte was filled with proteid yolk globules of high electron density and lipid yolk globules of low electron density. In this stage, the thickness of egg envelope was approximately 6.5 ${\mu}m$.

• Food Science of Animal Resources
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• v.30 no.4
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• pp.603-608
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• 2010

This study investigated the effects of electron beam irradiation on pathogens, quality, and functional properties of shell eggs during storage. A 1st grade 1-d-old egg was subjected to electron beam irradiation at 0, 1, 2, and 3 kGy, after which the number of total aerobic bacteria, reduction of inoculated Escherichia coli and Salmonella Typhimurium, egg quality, and functional properties were measured. Electron beam irradiation at 2 kGy reduced the number of E. coli and S. Typhimurium cells to a level below the detection limit (<$10^2$ CFU/g) after 7 and 14 d of storage. Egg freshness as measured by albumen height and the number of Haugh units was significantly reduced by 1-kGy irradiation. The viscosity of irradiated egg white was also significantly decreased by increased irradiation, whereas its foaming ability was increased. Electron beam irradiation also increased lipid oxidation in egg yolks. These results suggest that electron beam irradiation reduces the freshness of shell eggs while increasing the oxidation of egg yolk and improving important functional properties such as foaming capacity. Electron beam irradiation can also be applied to the egg breaking process since the irradiation reduces the viscosity of egg white, which can allow egg whites and yolks to be separated with greater efficiency.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1562-1569
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• 2004

The objective of this experiment was to determine the effects of n-3 polyunsaturated fatty acids (n-3 PUFAs)-enriched diet supplemented with different levels of $\alpha$-tocopherol on the activities of hepatic lipogenic-related enzymes and the contents of liver and plasma lipid fractions in laying Tsaiya ducks. A total of 180 30-wk-old laying Tsaiya ducks, at the beginning of peak production, were allotted into 6 treatments with 3 replicates each. Ducks were fed one of the 6 experimental diets, containing 4% tallow (control), and 4% fish oil supplemented with graded levels of $\alpha$-tocopheryl acetate ($\alpha$-tocopherol) at 0, 100, 200, 300 and 400 mg/kg, respectively, for 6 wks. Feed and water were supplied ad libitum throughout the experimental period. The results indicated that the n-3 PUFAsenriched diet supplemented with different levels of $\alpha$-tocopherol did not affect (p>0.05) egg weight, feed intake, body weight change or liver and abdominal fat weights. Egg production, egg mass and feed efficiency significantly (p<0.05) improved as dietary $\alpha$-tocopherol levels increased. The activities of hepatic lipogenic-related enzymes including acetyl-CoA carboxylase (EC 6. 2. 1. 3; ACC), glucose-6-phosphate dehydrogenase (EC 1. 1. 1. 49; G-6-PDH), ATP-citrate cleavage enzyme (EC 4. 1. 3. 8; CCE), NADP-malate dehydrogenase (EC 1.1.1.40; NADP-MDH) and fatty acid synthetase (FAS) were higher (p<0.05) in birds fed with the tallow diet than in those fed with fish oil diets and increased with increasing dietary $\alpha$-tocopherol levels. None of the dietary treatments significantly affected the contents of triglyceride and total cholesterol in the liver, or total cholesterol, phospholipid and total lipid in the plasma. However, the contents of phospholipid and total lipid in the liver, and triglyceride in the plasma increased as dietary $\alpha$-tocopherol levels increased. Increasing dietary $\alpha$-tocopherol levels decreased the non-esterified fatty acid (NEFA) content in the plasma and trended to decrease the cholesterol contents in the egg yolk. The lipid metabolism of laying Tsaiya ducks was influenced not only by the dietary fat but also by the supplementation levels of $\alpha$-tocopherol.

• Journal of Food Hygiene and Safety
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• v.14 no.1
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• pp.60-66
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• 1999

Diethylnitrosamine (DEN) is known as a potential hepatic carcinogen by single administration. This study was designed to measure the effects of DEN-induced cell damage on the triglyceride and cholesterol concentration in the liver, excluding dietary effects. Fertilized chicken eggs, 10 days before hatching, were randomly divided into three groups (n=20) and each egg was injected 10 ${mu}ell$ of corn oil (vehicle control), 5 $\mu\textrm{g}$ of DEN/10 ${mu}ell$ of DEN/10 ${mu}ell$ into yolk via air sac. After 48 hr and 96 hr incubation, the damage of the chick-embryo liver cell was investigated by electron microscopy and by measuring the concentration of lipid components (total cholesterol, free cholesterol, phospholipid and triglyceride). For eggs administered 10 $\mu\textrm{g}$ of DEN and incuvated 96 hr, in hepatocyte, the nucleus membrane was roughed, the size of nucleolus was apparently increased and euchromatin was accumulated. Mitochondria were condensed and cristae, located mitochondiral inner membrane, were obscured. Additionally, the leaves of triglyceride and cholesterol classes were significantly increased depend on the amount treated with 10 $\mu\textrm{g}$ DEN at 96 hr, but phospholipids component of cell membrane, were decreased with significance. As a conclusion, carcinogen induced hepatic lesion was correlated with the changes in lipid component of liver.

• Animal Bioscience
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• v.35 no.2
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• pp.236-246
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• 2022

Objective: The objective of this study was to investigate the effect of dietary pumpkin (Cucurbita moschata) seed meal (PSM) on laying hens' performance, quality, fatty acids, cholesterol, antioxidant compounds and shelf life of eggs. Methods: Eighty Tetra SL laying hens, 50-week-old, were randomly divided into two equal groups, having 10 replicates with 4 birds in each. The control (CON) treatment was fed with basal diet, while experimental treatment was fed a diet with 9% PSM, for a 6 week period. Results: Dietary PSM significantly decreased average daily feed intake (p<0.05), with no significant effect on other performance parameters. The PSM, enriched the eggs with polyunsaturated fatty acids, especially α linolenic acid (0.33 vs 0.21 g/100 g) and linoleic acid (20.65 vs 18.37 g/100 g), whereas it reduced the amount of arachidonic acid with 3.91% and n-6/n-3 ratio in PSM eggs compared with CON. The inclusion of 9% PSM significantly (p<0.05) diminished the cholesterol concentration in yolk with 11.31% and in egg with 10.38%, in respect to the CON samples. The significantly (p<0.05) higher concentration of polyphenols and antioxidant compounds, determined in PSM eggs, proved to be effective on shelf life of eggs preserved at refrigerator (5℃) and room temperature (21℃) for 28 days, by delaying the lipid oxidation and protein denaturation. This effect was reflected in significantly (p<0.05) higher Haugh unit in eggs stored 28 days at 21℃ and lower albumen pH values for the overall storage time, both at 5℃ and 21℃, proving the antioxidant effect of pumpkin. Conclusion: Dietary PSM supplementation was significantly effective on average daily feed intake and egg quality by increasing some fatty acids while lowering the cholesterol concentration. Also, PSM proved to be effective improving shelf life of eggs for 28 days storage time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.2
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• pp.143-152
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• 1989

Some sugars and proteins were mixed with yellow corvenia lipids, soybean lipids or see yolk lipids to study the influence of the sugars or proteins on lipid oxidation and browning in dry and wet system during kept at $40^{\circ}C$. In the yellow corvenia lipids mixed with various food components, peroxide value(POV), carbonyl value(COV) and brown pigments were much higher than the case that soybean lipids or egg folk lipids were mixed. In terms of the food components, they appealed high in glucose, sucrose and starch but low in albumin and casein. When the soybean lipids were mixed, POV appeared low in all these maxture. COV and brown pigments appeared high in glucose, sucrose and starch but low in albumin and casein. In the case of egg york lipids, POV appeared lower than that of soybean lipids but COV and brown pigments were similar. In the starch mixture of three lipids in wet system, POV and COV in yellow corvenia lipids appealed lower, but appeared higher in soybean lipids and egg yolk lipids than those in dry system. Brown pigments appeared similarly with the case in dry system. And the all mixtures of casein in wet system, POV and COV appealed lower thanthose of the dry system, but brown pigments appeared high.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.16-18
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• 2002

During the process of freezing, spermatozoa suffer cold shock which increases their susceptibility to lipid peroxidation which plays an important role in ageing of spermatozoa, shortening their life span and affecting the preservation of semen. An experiment was therefore conducted to study the effect of addition of natural antioxidants into semen diluents on the preservability of buffalo semen. Split semen samples were extended in milk egg yolk diluents fortified with vitamin E (MYE), vitamin C (MYC) and control group (MYO); Tris-egg yolk diluents fortified with vitamin E (TYE), vitamin C (TYC) and control group (TYO) and evaluated for their preservabilities at 4-7$^{\circ}C$ and $37^{\circ}C$. Overall least squares mean of percent motility observed after 0, 24, 48, 72 and 96 h of preservation at 4-7$^{\circ}C$ were 66.70, 54.00, 36.80, 21.90 and 12.50, respectively while the estimates for semen extended in MYE, MYC, MYO, TYE, TYC and TYO were 44.80, 42.70, 38.70, 36.00, 35.20 and 33.00 percent, respectively. The results showed that motility was significantly (p<0.01) affected by extender (extender-antioxidant combination) and preservation interval. Overall least squares mean percent motility observed after 0, 4, 8, 12 and 24 h of preservation at $37^{\circ}C$ were 68.50, 58.90, 45.00, 38.10 and 18.10 percent, respectively, while the estimates for semen extended in MYE, MYC, MYO, TYE, TYC and TYO were 48.20, 49.30, 46.80, 45.30, 42.30 and 42.50 percent, respectively. Extender and storage interval were found to be significantly (p<0.01) affecting spermatozoa motility on room temperature preservation. The results indicated that the incorporation of antioxidants, especially vitamin E, had beneficial effect on preservability of buffalo semen.