Evaluating the antioxidant status of weanling pigs fed dietary vitamins A and E

Two experiments evaluated the relationship of vitamin E (source and level) and vitamin A (level) on the apparent absorption and retention of both vitamins in weaned pigs. Both experiments used a combined total of 460 crossbred pigs ([Yorkshire x Landrace] x Duroc), housed in elevated 1.2- x 1.2-m crates containing five pigs per pen. Experiment 1 was a 2 x 2 x 2 factorial arrangement of treatments in a randomized complete block design conducted in seven replicates. Levels of vitamin A (2,200 or 13,200 IU/kg), vitamin E (15 or 90 IU/kg), and two vitamin E sources (D-alpha-tocopheryl acetate [D-TAc] or DL-alpha-tocopheryl acetate [DL-TAc]) were evaluated over a 35-d period. Vitamin A or E levels and the two vitamin E sources did not affect pig performances to 20 kg BW. Serum retinol and alpha-tocopherol concentrations increased (P < 0.01) as the dietary level of each vitamin increased. Serum alpha-tocopherol declined as dietary vitamin E level increased when vitamin A level increased resulting in an interaction (P < 0.05). Serum alpha-tocopherol concentrations were higher (P < 0.05) at 35-d postweaning when D-TAc was the vitamin E source. Experiment 2 was a 3 x 2 factorial arrangement of treatments conducted in six replicates. Three levels of vitamin A (2,200, 13,200, or 26,400 IU/ kg) and two sources of vitamin E (D-TAc or DL-TAc) each provided at 40 IU/kg diet were evaluated over a 35-d period. Pig performances to 35-d postweaning were not affected by the dietary variables. Serum alpha-tocopherol (P < 0.01) and retinol (P < 0.05) concentrations increased as their respective vitamin level increased. Serum (P < 0.05) and liver (P < 0.01) alpha-tocopherol concentrations both declined as dietary vitamin A levels increased resulting in interaction responses. Serum alpha-tocopherol concentration was higher (P < 0.05) at 35-d postweaning when d-TAc was the vitamin E source. Dietary vitamin E sources had no effect on serum or liver retinol concentrations. These results demonstrated that both supplemental vitamin A and vitamin E increased in the blood as their dietary levels increased. However, as dietary vitamin A level increased, serum and liver alpha-tocopherol concentrations declined, suggesting a reduced absorption and retention of alpha-tocopherol when weaned pigs were fed high dietary vitamin A levels.     

The effect of dietary vitamin E level on selenium status in rats

The effect of varying levels of dietary vitamin E on selenium status was determined using 40 Wistar rats with similar initial body weight. The rats were equally divided into four groups and fed the following dietary treatments (mg vitamin E/kg DM): 18 (control; C‐diet), 0 (0E‐diet), 9 (0.5E‐diet) and 36 (2E‐diet) for either 4‐week (Phase 1) or 8‐week (Phase 2) period. At the end of experiment, animals were slaughtered to measure vitamin E and selenium levels in the brain, liver, spleen, kidney, muscles and blood tissues. Dietary vitamin E levels did not affect feed and water intake and body weight. But whole‐blood selenium concentration in rats fed 0E‐diet was higher than in rats fed 2E‐diet after 4 weeks. Selenium level in muscle, spleen and brain was also higher (p < 0.05) in rats fed the 0E‐diet than in rats fed C‐diet after 4 weeks of feeding. On the other hand, selenium level in the muscle was lower (p < 0.05) in rats fed 0.5E‐diet than in those fed 0E‐diet after 4 weeks of feeding, but not after 8 weeks of feeding. Increasing dietary vitamin E level directly influenced selenium content of the spleen and brain after 8 weeks of feeding 2E‐diet. Moreover, the twofold increase in vitamin E intake resulted in a tendency to reduce whole‐blood selenium level and total selenium in the liver and kidney after 4 and 8 weeks. The results showed that the increasing dietary vitamin E level resulted in a tendency to reduce Se contents in some vital organs of the body such as the liver and kidney, suggesting their close compensatory interrelationship. Therefore, dietary vitamin E level directly influenced selenium metabolism in the animal body.     

The effect of an oxidized dietary oil on plasma cholesterol and thyroid hormone concentrations in miniature pigs fed on a hyperlipidaemic diet

Introduction Polyunsaturated fatty acids (PUFA) are labile compounds which under the promoting effect of oxygen, high temperature or metallic catalysts undergo peroxidative damage. In the course of lipid peroxidation, several primary and secondary products such as peroxides, aldehydes, dimers or polymers are formed. Human western diets are not only generally rich in fats, but also rich in fats that have been subjected to various degrees of processing and heat treatment, particular deep fat frying. The absolute intake of lipid peroxidation products in western countries varies over a wide range, depending on the individual eating habits; however, it can be assumed that on average of the population at least 50% of the fat consumed has been heated during industrial processing of foods or preparing of meals. Therefore, the potential toxic effects of products formed from polyunsaturated fatty acids during heating or frying of fats are of particular interest for human health, particularly in the development of coronary heart disease. In literature, there is one study which reports that the development of atherosclerosis is accelerated by dietary oxidized lipids in cholesterol-fed rabbits (S trapans et al. 1996). The reason for this observation, however, is not clear. The pathogenesis of atherosclerosis is very complex. Undoubtedly, the concentration of cholesterol in plasma and in lipoproteins as well as the susceptibility of low-density lipoproteins to lipid peroxidation are major factors influencing the risk of coronary heart disease (S teinberg et al. 1989; M archioli et al. 1996). In order to clarify a potential relationship between the intake of dietary oxidized lipids and an increased risk of coronary heart disease, this study investigated the effects of feeding oxidized oils on the concentrations of lipids in plasma and lipoproteins and the susceptibility of plasma lipids to peroxidation (S taels et al. 1990; T anis et al. 1996). The concentrations of thyroid hormones in plasma were measured because they are in close relationship with the plasma cholesterol concentration. Miniature pigs that were fed a cholesterol-enriched diet were used in this study because they have been described to be an adequate model for the investigation of the lipid metabolism in humans (B arth et al. 1990). A general problem in the investigation of the effects of dietary oxidized lipids is that the administration of a diet containing highly oxidized fats reduces food intake, food efficiency and the digestibility of fatty acids (C orcos benedetti et al. 1987; Y oshida and K ajimoto 1989; B lanc et al. 1992; H ayam et al. 1993; B orsting et al. 1994; L iu and H uang 1996; H ochgraf et al. 1997). Moreover, because of strong oxidation, highly oxidized oils usually contain significantly less PUFA and tocopherols than the equivalent fresh oils (D& rsquo ; aquino et al. 1985; C orcos benedetti et al. 1987; B lanc et al. 1992; B orsting et al. 1994; H ayam et al. 1995; L iu and H uang 1995; H ochgraf et al. 1997). In order to avoid these problems a controlled feeding system was used in this study and dietary fats were equalized for their fatty acid composition and tocopherol concentrations. Studies from literature reported that dietary oxidized oils reduce tocopherol concentrations and thereby alter the fatty acid composition of tissues and increase the fragility of erythrocyte membranes in animals (C orcos B enedetti et al. 1987; Y oshida and K ajimoto 1989; B lanc et al. 1992; H ayam et al. 1993). However, as mentioned above, in most of the studies reported in literature, the concentration of vitamin E was significantly lower in diets containing oxidized oils than in control diets. In order to find out whether those effects are also observed if diets are adjusted for identical vitamin E activities, this study also measured the tocopherol concentration in plasma, the fatty acid composition of erythrocyte lipids and the osmotic fragility of erythrocytes.     

不同饱和度脂肪添加抗氧化剂对瘤胃发酵、抗氧化状态和微生物区系的影响

利用体外产气法研究不同饱和度脂肪和抗氧化剂添加对湖羊瘤胃体外发酵参数的影响。试验采用2×2因子设计,试验因素为脂肪类型(全饱和与50%饱和度)和抗氧化剂(0或500mg/kg)。结果显示,脂肪类型不影响瘤胃发酵参数和抗氧化状态(P>0.05),与饱和脂肪相比,补充不饱和脂肪可显著降低瘤胃液中产琥珀酸丝状杆菌相对于总菌的比例(P<0.05)、提高原虫的比例(P<0.05)。添加抗氧化剂可提高瘤胃体外24h产气量和有机物消化率(P<0.05),并有减少乙酸摩尔比、增加丙酸摩尔比的趋势(P<0.10)。添加抗氧化剂有降低瘤胃丙二醛、提高超氧化物歧化酶活性的趋势(P<0.10)。抗氧化剂对黄色瘤胃球菌和白色瘤胃球菌的影响与脂肪类型有关,不饱和脂肪添加抗氧化剂可显著提高黄色瘤胃球菌和白色瘤胃球菌相对于总菌的比例,而饱和脂肪添加无显著影响。上述结果表明,日粮添加不饱和脂肪不利于纤维分解菌的生长,添加抗氧化剂可改善不饱和脂肪对瘤胃微生物的影响,而对饱和脂肪影响较小;添加抗氧化剂还可改善瘤胃抗氧化状态、提高有机物的消化率。     

The effect of administration of copper nanoparticles to chickens in their drinking water on the immune and antioxidant status of the blood

The aim of this experiment was to determine what dosage of copper (Cu) nanoparticles, added to a standard dietary supplementation with copper sulfate, would improve antioxidant and immune defense in chickens. The experiment was conducted with 126 broiler chickens assigned to seven treatments with three pens per treatment and six broiler chickens per pen. The basal‐diet treatment did not receive Cu nanoparticles (nano‐Cu) and as shown by analyses it was Cu‐deficient (?29% vs. National Research Council (NRC) recommendations; 5.7 vs. 8 mg/kg). Broiler chickens received nano‐Cu (0.5, 1.0 or 1.5 mg/kg body weight per day) via a tube into the crop over three 3‐day periods (days 8–10, 22–24 and 36–38) or three 7‐day periods (days 8–14, 22–28 and 36–42). As a result, in the nano‐Cu‐treated broilers the total experimental Cu intake was from ?11% to +96% versus NRC recommendations. At the age of 42 days of broilers, their blood indices were determined. The obtained results showed that correction of the deficient basal diet of chickens with nano‐Cu to a level of copper exceeding the NRC recommendation by 54% increased the antioxidant potential of the organism and inhibited lipid peroxidation. At the dosage of +96% versus NRC, some symptoms of a deterioration in antioxidant status appeared (a decrease in the level of glutathione plus glutathione disulfide and an increase in superoxide dismutase, catalase and ceruloplasmin activity and in lipid hydroperoxide content). Additionally, +7% versus the recommended Cu dietary level was followed by unfavorable results, indicating a deterioration in red blood cell parameters and stimulation of the immune system (an increase in interleukin‐6, immunoglobulin A (IgA), IgM and IgY). To conclude, it was shown that it is possible to simultaneously increase antioxidant and immune defense of chickens by supplementing their diets with nano‐Cu – up to 12 mg per bird during 6 weeks of feeding, that is to a level no more than 7% over the NRC recommendation for growing broiler chickens.     

Reproductive performance and gestational effort in relation to dietary fatty acids in guinea pigs

Background: Dietary saturated(SFAs) and polyunsaturated(PUFAs) fatty acids can highly affect reproductive functions by providing additional energy, modulating the biochemical properties of tissues, and hormone secretions. In precocial mammals such as domestic guinea pigs the offspring is born highly developed. Gestation might be the most critical reproductive period in this species and dietary fatty acids may profoundly influence the gestational effort. We therefore determined the hormonal status at conception, the reproductive success, and body mass changes during gestation in guinea pigs maintained on diets high in PUFAs or SFAs, or a control diet.Results: The diets significantly affected the females' plasma fatty acid status at conception, while cortisol and estrogen levels did not differ among groups. SFA females exhibited a significantly lower body mass and litter size, while the individual birth mass of pups did not differ among groups and a general higher pup mortality rate in larger litters was diminished by PUFAs and SFAs. The gestational effort, determined by a mother's body mass gain during gestation, increased with total litter mass, whereas this increase was lowest in SFA and highest in PUFA individuals. The mother's body mass after parturition did not differ among groups and was positively affected by the total litter mass in PUFA females.Conclusions: While SFAs reduce the litter size, but also the gestational effort as a consequence, PUFA supplementation may contribute to an adjustment of energy accumulations to the total litter mass, which may both favor a mother's body condition at parturition and perhaps increase the offspring survival at birth.     

The effect of dietary nitrite and nitrate on the metabolism of sulphadimidine administered orally to pigs

The in vivo interaction of sulphadimidine (SDM) with nitrite and nitrate has been investigated in pigs. It was shown that the combined oral treatment with SDM and nitrite but not nitrate leads to the formation of a deaminated compound, which becomes the major metabolite in plasma soon after cessation of the treatment. The major in vitro reaction product, 1,3-di(4-[N(4,6-dimethyl-2-pyrimidinyl)]-sulphamoylphenyl)-triazen e, DDPSPT as has been reported previously, could not be detected in blood, urine or faeces of the exposed animals. No effect of nitrite or nitrate could be observed on the acetylation of SDM.     

The effect of the selenium status of goats on the resistance of erythrocytes to oxidative damage

The effect of selenium status on the development of Heinz body anaemia was studied in 16 three months old Saanen goats which received a diet with a low selenium content. The control group (Se-, n = 8) received no supplementary selenium while the treated group (Se+, n = 8) received selenium by injection. Erythrocyte glutathione peroxidase concentration was significantly higher in the Se+ group than in the control group (105 vs 36 U/g Hgb). The animals were drenched once per day with 30 mg of dimethyl disulphide (DMDS) per kg of body weight for 14 days and with 50 mg per kg during the following 11 days. Erythrocytes with Heinz bodies appeared within one week after increasing the DMDS dose to 50 mg/kg/day and reached a peak one week later (30% and 37% of erythrocytes with Heinz bodies in group Se+ and Se- respectively). Within the next three weeks haemoglobin levels dropped from 135 g/l to 123 g/l and 114 g/l in the Se+ and the Se- group respectively. Differences between the two groups were statistically significant for the percentage of erythrocytes with Heinz bodies and for haemoglobin values (p less than 0.05). The data support the hypothesis that selenium status influences the resistance of ruminants to brassica-induced Heinz body anaemia.     

茶多酚对生长猪机体维生素E状态、抗氧化性能及肉质的影响

日粮添加维生素E对降低动物脂质过氧化具有重要作用,可以改善动物肉品质及动物健康状况。本试验在日粮中添加不同水平的茶多酚,研究其对生长猪维生素E状态、血浆抗氧化性能及肉质的影响。选择240头平均体重为(31.24±0.48)kg的三元猪,随机分为3组,每组4个重复,每个重复20头猪。试验共设计3种日粮,对照组饲喂基础日粮,处理组在基础日粮中分别添加10和100 mg/kg茶多酚,试验共进行5周。结果显示:各处理组对生长猪试验初期和末期血浆总抗氧化力和铁还原力均无显著影响(P> 0.05),但对照组、10和100 mg/kg茶多酚添加组血浆试验末期铁还原力均显著高于试验初期(P <0.05)。日粮添加茶多酚对生长猪肝脏、肌肉、血浆α-生育酚和γ-生育酚含量均无显著影响(P> 0.05),其中肝脏生育酚含量最高,之后依次是肌肉、肺和血浆。日粮添加10或100 mg/kg茶多酚,肺中α-生育酚和γ-生育酚含量较对照组有提高趋势(P=0.09)。各组对生长猪肉质均无显著影响(P> 0.05)。日粮添加100 mg/kg茶多酚较对照组提高了生长猪屠宰后48 h肌肉的滴水损失。综上所述:生长猪日粮添加茶多酚对组织维生素E水平、血浆抗氧化力及肌肉品质无显著改善作用。     

The effect of some drugs injection to pregnant heifers on blood antioxidant status

The purpose of the trial was to establish the effect of the injection of the lysozyme dimer or vitamins connected with Se on the activity of chosen antioxidant enzymes and the total antioxidant status in pregnant heifers. Examinations were carried out during winter season in one farm on 21 heifers aged 22-24 months. Between the 21st and 14st day before expected parturition, seven heifers were once i.m. injected with antioxidants (Vitamin A-600 000 i.u.; Vitamin D3-200 000 i.u.; Vitamin E-1.5 mg/kg b.w., Selenium-0.022 mg/kg b.w.), and the next seven animals with lysozyme dimer (Lydium-KLP) at a dose of 0.02 mg/kg b.w. versus 7 non-treated control animals. Blood samples were taken before injection and then in hour 24 and 72 after injection, and between, the 7th and 14th day after calving. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSHpx), glutathione reductase (GSHred) and total antioxidant status (TAS) were measured by colorimetric method with the use of Randox kits. The mean value of SOD activity 21-14 days before expected calving was 704.8 +/- 294.6 U/ml of whole blood, GSHpx 59222 +/- 23699 U/l of whole blood, GSHred 110.8 +/- 22.5 U/l and TAS 0.33 +/- 0.15 mmol/l of serum. These indicators did not change in the control group with the exception of a statistically insignificant decrease in SOD activity after parturition. Statistically significant increase in blood SOD activity was noted only in the first day after injection of vitamins combined with selenium. These antioxidants also caused an insignificant increase in blood GSHpx activity in 72 hour following the injection, and in the second week after calving (statistically significant). The injection of antioxidants or lysozyme dimer did not change the activity of blood GSHred. However, an increase in the TAS was found in hour 24 (non significant) and 72 (statistically significant) following the single injection of lysozyme dimer.     

Effect of dietary antioxidant supplementation on the oxidative status of plasma in broilers

In this study, the effect of dietary antioxidants on the plasma oxidative status of growing birds fed a diet rich in polyunsaturated fatty acids was investigated. One‐day‐old broilers were fed for 42 days a diet containing 4% linseed oil and supplemented with single plant extracts rich in antioxidants (natural tocopherols, rosemary, grape seed, green tea, tomato) or a combination of some of these plant extracts, in two different total doses (100 and 200 mg product/kg feed). A diet with synthetic antioxidants with and without α‐tocopheryl acetate (200 mg/kg feed) were also included. The plasma oxidative status was evaluated measuring the ferric reducing ability of plasma (FRAP), the superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) activity. Lipid peroxidation was measured by thiobarbituric acid‐reactive substances (TBARS). No significant effect of the dietary treatments was observed for FRAP as well as for TBARS. However, diet affected GSH‐Px activity (p = 0.002) and a trend for an effect on SOD activity was observed (p = 0.084). A higher GSH‐Px activity was found for 200 mg/kg tomato extract and natural α‐tocopherol in relation to the corresponding 100 mg/kg treatment, and the lowest GSH‐Px activity was measured for the synthetic antioxidants treatment. The lowest and highest SOD activity were found for the 200. and 100 mg/kg treatment with tomato extract respectively. In conclusion, the oxidative status and lipid oxidation of plasma in broilers was not affected by feeding natural antioxidant extracts at the doses in the present study, but some changes in antioxidant enzyme activities were observed, of which the implication remains to be elucidated.     

The effect of Cirsium arvense extract on antioxidant status in quail

1. The herb Creeping Thistle, Cirsium arvense (C. arvense), has been used in folk medicine due to its antioxidant and anti-inflammatory effects.

2. The aim of this study was to investigate the effects of dietary C. arvense extract supplementation on performance, egg quality, nutrient digestibility and antioxidant status in quail.

3. Quails (n = 150) were allocated randomly to one of the three dietary treatments: basal diet and basal diet enriched with 100 and 200 mg C. arvense extract per kg diet.

4. Dietary enrichment with C. arvense extract altered neither performance and egg quality parameters nor nutrient digestibility. Although there were no changes in concentrations of vitamin A and E in serum, liver and egg yolk, supplemental C. arvense extract decreased MDA concentrations in serum, liver and egg yolk by 39.3, 40.5 and 51.5%, respectively, in a dose-response manner. As supplemental C. arvense extract increased to 200 mg/kg, the activity of hepatic SOD, CAT and GSH-Px increased by 14.5, 17.4 and 35.5%, respectively.

5. Addition of C. arvense extract up to 200 mg to per kg diet enhanced antioxidant status in laying quail and their eggs, without affecting performance and other egg quality parameters.

6. Future studies are needed to elucidate the mechanism behind the antioxidant effects of C. arvense extract.     

Development of an arterial thrombosis model in pigs for investigating the thrombogenicity of different dietary fats

A surgically induced model of arterial thrombosis in pigs (60–80 kg live weight) has been developed using a balloon angioplasty technique. The purpose of this model is to assess the thrombogenicity of milkfat in comparison with other dietary lipids, thereby assessing its importance in the pathogenesis of human coronary heart disease. Balloon angioplasty catheters (Meditech, 3 cm X 8 mm balloon) are inserted into the left and right femoral arteries via a cut-down on to the saphenous artery. The balloons are inflated five times for 30 seconds with 30 second intervals between inflations. This results in endothelial denudation, exposure of sub-endothelial connective tissue and formation of platelet rich thrombi. Thrombus size is quantitated using autologous blood platelets labelled with ⁹⁹Tc-HMPA0 (technetium - “Deretec”).     

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background

This study was designed to evaluate the efficacy of DL-selenomethionine (DL-SeMet) supplementation on growth performance, antioxidant status, plasma selenium (Se) concentration, and immune function of weaning pigs. 216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design. Each replicate had six pigs. Diet of group one was corn-soybean basal diet without any additional Se supplement. Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite. Groups 3-6 were supplemented with 0.1, 0.3, 0.5, and 0.7 mg/kg of Se from DL-SeMet, respectively. The trial lasted for 42 days.

Results

Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio (P < 0.05). The best antioxidant ability (serum, liver, and muscle) was shown in 0.1-0.3 mg/kg DL-SeMet groups (P < 0.05). The plasma Se concentration increased as the dietary DL-SeMet level elevated. The immunity among groups was not affected.

Conclusions

DL-SeMet supplementation in the diet significantly improved the growth performance, antioxidant ability and plasma Se content of weaning pigs. DL-SeMet can replace sodium selenite in the diet of weaning pigs.     

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background:This study was designed to evaluate the efficacy of DL-selenomethionine(DL-SeMet) supplementation on growth performance,antioxidant status,plasma selenium(Se) concentration,and immune function of weaning pigs.216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design.Each replicate had six pigs.Diet of group one was corn-soybean basal diet without any additional Se supplement.Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite.Groups 3-6 were supplemented with 0.1,0.3,0.5,and 0.7 mg/kg of Se from DL-SeMet,respectively.The trial lasted for 42 days.Results:Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio(P 0.05).The best antioxidant ability(serum,liver,and muscle) was shown in 0.1-0.3 mg/kg DL-SeMet groups(P 0.05).The plasma Se concentration increased as the dietary DL-SeMet level elevated.The immunity among groups was not affected.Conclusions:DL-SeMet supplementation in the diet significantly improved the growth performance,antioxidant ability and plasma Se content of weaning pigs.DL-SeMet can replace sodium selenite in the diet of weaning pigs.     

Potentiating effect of adjuvants on humoral immunity to porcine parvovirus vaccines in guinea pigs

Fourteen different adjuvants, given either in single or combined form with another compound were compared in guinea pigs for their ability to potentiate humoral immunity to porcine parvovirus (PPV) antigen after 2 vaccinations. Two injections were given, the second 3 weeks following the initial vaccination. Antibody concentrations to PPV in sera from injected animals were measured over a 5-week period by the hemagglutination inhibition test. At the conclusion of the experiment, guinea pigs injected with the following adjuvants and PPV antigen: CP-20 961 (Avridin), 50% aluminum hydroxide gel, ethylene maleic anhydride (EMA), oil and water emulsion (O/W) and dimethyl-dioctadecyl-ammonium bromide (DDA) immunologically responded with high geometric mean HI titers (380, 224 and 427, 602, 512, 1202 respectively), whereas guinea pigs receiving Emulsan, sodium dodecyl sulfate (SDS), L-121, combinations of Emulsan/aluminum hydroxide, SDS/aluminum hydroxide and B. pertussis/aluminum hydroxide responded with low mean titers (54, 64, 18, 27, 11, 64, 14, 20 respectively). Guinea pigs injected with antigen without adjuvant responded weakly with geometric mean titers of 3.3 and 16 for the 2 groups tested. Prior to booster injection, guinea pigs immunized with 13 of the preparations had low (less than 4) or undetectable antibody titers. Antibody titers from guinea pigs receiving DDA adjuvant continued to rise throughout the duration of the experiment and at the conclusion had the highest mean titers of the groups tested (1202). The 2 groups immunized with 50% aluminum hydroxide gel had high mean titers (224, 427), but in both instances there was a wide range of titers within a group evidenced by high standard deviations. In contrast, guinea pigs receiving either DDA, CP-20 961, O/W or EMA had antibody titers within a narrow range and small standard deviation. The significance of aluminum hydroxide gel concentration on immunogenicity is discussed.     

Effect of dietary conjugated linoleic acid on vitamin A status of lactating rats and their offspring

The absorption and metabolism of vitamin A is linked with that of lipids. It is known that conjugated linoleic acid (CLA) affects the lipid metabolism in growing and lactating animals. In the present study, the hypothesis was investigated that dietary CLA influences vitamin A status of lactating rats and their pups during the suckling period. For this purpose, Wistar Han rats were fed either a control diet (control group, n = 14) or a diet containing 0.87% of cis‐9, trans‐11 and trans‐10, cis‐12 (1:1) CLA (CLA group, n = 14) during pregnancy and lactation. Vitamin A concentrations in various body tissues were determined 14 days after delivery in dams and 1, 7 and 14 days after birth in pups, and expression of selected genes involved in metabolism of retinoids was determined in dams. Vitamin A concentrations in liver, plasma and muscle were similar in control and CLA‐fed dams. Expression of genes involved in retinoid transport, storage and degradation in liver and adipose tissue in dams was also not different between control and CLA‐fed dams. Vitamin A concentrations in milk curd, sampled at d 1, 7 and 14 of lactation were not different between control and CLA‐fed dams. Vitamin A concentrations in liver, lung and adipose tissue were also not different in pups from control dams and pups from CLA‐fed dams. In conclusion, we show for the first time that dietary CLA has little effect on vitamin A concentrations and vitamin A metabolism in lactating rat dams and, moreover, does not influence tissue vitamin A concentrations in their newborn and suckling pups.