'I don't want my son to be part of a giant experiment': public attitudes towards COVID-19 vaccines in children.

OBJECTIVES: This qualitative study explored public attitudes to COVID-19 vaccines in children, including reasons for support or opposition to them. STUDY DESIGN: This was a qualitative study using online focus groups and interviews. METHODS: Group and individual online interviews were conducted with a diverse sample of 24 adults in the United Kingdom to explore their views on the issue of COVID-19 vaccination in children. Data were analysed using a framework approach. RESULTS: COVID-19 vaccination in children was framed as a complex problem (a 'minefield'). Six themes emerged to explain participants views: (1) uncertainty over whether children can catch, transmit or be severely harmed by COVID-19; (2) lower risk tolerance for unknown longer term effects of the vaccine in children; (3) association of the vaccine programme with government's handling of the pandemic; (4) local social norms as a driver of hesitancy; (5) vaccinating children as a way to protect vulnerable adults; and (6) children's vaccination as parental choice. CONCLUSIONS: COVID-19 vaccination in children is perceived by members of the public as a complex issue, and many are torn or hesitant about the idea. Public health communications will need to combat this hesitancy if vaccine uptake for children is to be pursued as a public health policy.

Short communication: serum and tissue concentrations of vitamin D metabolites in beef heifers after buccal dosing of 25-hydroxyvitamin D3.

Sixteen crossbred (British x Continental; average un-shrunk body weight = 507.9 kg; SD = 45.6 kg) beef heifers fed a steam-flaked corn-based finishing diet with melengestrol acetate (0.4 mg/heifer daily) included to suppress estrus were used in a completely random design to evaluate the efficacy of buccal administration of 0, 10, 100, or 1000 mg of 25-hydroxyvitamin D3, (25-OH D3). Serum Ca, P, Mg, 25-OH D3, 1,25-dihydroxyvitamin D [1,25-(OH)2 D3], albumin, and protein were measured 24 h before dosing (-24 h), at dosing (0 h), and 6 and 24 h after dosing, after which the cattle were slaughtered at a commercial facility. Samples of kidneys, liver, longissimus lumborum, and triceps brachii were collected and evaluated for concentrations of 1,25-(OH)2 D3. With -24 and 0 h as baseline covariates, a significant time x treatment interaction was observed for serum 25-OH D3 and Ca concentrations, but not for serum 1,25-(OH)2 D3. Supplemental 25-OH D3 doses of 100 and 1000 mg significantly increased serum 25-OH D3 at 24 h after dosing, 1,25-(OH)2 D3 at 6 and 24 h after dosing, and serum Ca at 24 h after dosing. Similarly, buccal dosing of 1000 mg of supplemental 25-OH D3 significantly increased (approximately 2- to 3-fold) concentrations of 1,25-(OH)2 D3 in the kidney, liver, and longissimus lumborum relative to the other 3 treatments but not in triceps brachii. Serum albumin, protein, P, and Mg were not affected by treatment. Based on these results, buccal administration of 100 and 1000 mg 25-OH D3 increased vitamin D3 metabolites in serum and tissues, and it should be an effective method of delivering the vitamin.

Effects of gossypol from cottonseed meal and dietary vitamin E on the reproductive characteristics of superovulated beef heifers.

Superovulated Hereford-Angus crossbred heifers (average 397 kg BW) were used to test the effect of feeding cottonseed meal (gossypol) and vitamin E on embryo quality and ovarian characteristics. Twenty-four heifers were assigned randomly to four treatments with six heifers per treatment. Treatments were the following dietary supplements: 1) SBM (soybean meal + 30 IU vitamin E/kg of diet DM); 2) SBM+E (soybean meal + 4,000 IU vitamin E x animal(-1) x d(-1)); 3) CSM (cottonseed meal + 30 IU vitamin E/kg of diet DM); and 4) CSM+E (cottonseed meal + 4,000 IU vitamin E x animal(-1) x d(-1)). Supplements based on cottonseed meal provided 43.5 g of total gossypol/d (37% negative isomer (-) and 63% positive isomer (+)). Blood samples were collected at the start of the experiment and every 3 wk thereafter up to 12 wk. Plasma a-tocopherol (alpha-T) concentration was affected by treatments (P < 0.05). Heifers supplemented with cottonseed meal had greater (P < 0.05) alpha-T concentration in plasma than heifers supplemented with soybean meal at each concentration of vitamin E. Supplementation at 4,000 IU vitamin E x animal(-1) d(-1) increased (P < 0.05) the concentration of a-T in plasma. Weight gain, hemoglobin and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P < 0.05) in cottonseed meal-fed animals; however, EOF was lowered (P < 0.05) with vitamin E supplementation. Heifers fed CSM and CSM+E supplements had greater (P < 0.01) concentrations of (-)-, (+)-, and total-gossypol in plasma, corpora lutea (CL), liver, and endometrium than heifers fed SBM and SBM+E supplements. Tissue alpha-T concentration increased with increased dietary supplemental vitamin E, particularly in great amounts in the CL. Because there was no adverse effect of gossypol on superovulation response or embryo development despite concentrations of gossypol in endometrium that are toxic to embryos, it is likely that systems exist in the reproductive tract to limit gossypol toxicity.

The use of a high-volume screening procedure to assess the effects of dietary flavonoids on human cyp1a1 expression.

We examined the effects of several agents, including dietary flavonoids, on CYP1A1 expression utilizing a recently developed high-throughput screening system for assessing human cytochrome P450 (CYP) induction. HepG2 cells, stably integrated with regulatory regions of human CYP1A1, were treated with resveratrol, apigenin, curcumin, kaempferol, green tea extract (GTE), (-)-epigallocatechin gallate (EGCG), quercetin, and naringenin. Of these flavonoids, resveratrol produced the greatest increase in CYP1A1-mediated luciferase activity (10-fold), whereas GTE, apigenin, curcumin, and kaempferol produced 2- to 3-fold increases in activity. Compared with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), omeprazole, or benzanthracene, where increases in luciferase activity ranged from 12- to 35-fold, these flavonoids exhibited weak agonist activity. The remaining compounds, EGCG, quercetin, and naringenin, produced negligible effects. Cotreatment of cells with TCDD and GTE, naringenin, and apigenin resulted in 58, 77, and 74% reductions, respectively, in TCDD-mediated CYP1A1 induction, indicating that these flavonoids exhibit potential antagonist activity toward the aryl hydrocarbon (Ah) receptor. Furthermore, results also suggest that GTE and apigenin possess Ah receptor antagonist and weak agonist activities. Thus, we have shown that a 96-well plate assay allowing high-throughput screening for P450 induction in less than 24 h was efficient in determining the effects of flavonoids on human CYP1A expression. Signal-to-noise ratios were low, and well-to-well and replicate variability was below 10%, allowing induction to be easily detected in this system. These features illustrate the reliability and feasibility of this high-volume screening system for identifying CYP inducers. Furthermore, results produced with the stable cell line were corroborated in HepG2 cells and primary cultures of human hepatocytes, suggesting that stably integrated cell lines harboring enhancer elements of P450 genes may be highly conducive to high-throughput screening.

Comparative studies on the effects of green tea extracts and individual tea catechins on human CYP1A gene expression.

Green tea possesses significant anticancer activity in numerous experimental animal models, including demonstrated protection against aryl hydrocarbon induced cancers. The aryl hydrocarbon receptor (AhR) mediates the transcriptional activation of CYP1A1 and CYP1A2. In the present study, we investigated the effects of commercially available green tea extracts (GTEs) and individual tea catechins on the function of the AhR and on CYP1A gene expression in human hepatoma HepG2 cells and primary cultures of human hepatocytes. GTEs inhibited the transcription of a human CYP1A1 promoter-driven reporter gene induced by the AhR ligand 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) in a concentration-dependent manner and inhibited the induced accumulation of both CYP1A1 and CYP1A2 mRNAs. GTEs blocked TCDD-induced binding of the AhR to DNA in HepG2 cells and in vitro in isolated hepatic cytosol. To determine if the observed effects were due to a single green tea component, we examined the four major catechins present in GTEs. Only (-)-epigallocatechin gallate (EGCG), the most abundant catechin in green tea, was able to inhibit TCDD-induced binding of the AhR to DNA and subsequent CYP1A transcription, however EGCG alone was less effective than GTEs. We next examined GTEs and catechins for AhR agonist activity. GTEs caused a concentration-dependent increase in CYP1A1-promoter driven reporter gene activity and caused accumulation of CYP1A1 mRNA and protein, but we found that individual catechins were unable to induce the expression of CYP1A1. Our results demonstrate that GTEs as a whole exert mixed agonist/antagonist activity on the AhR, while EGCG functions as a strict AhR antagonist. Therefore, modulation of human CYP1A expression by green tea extracts can not be attributed to the action of a single tea catechin, but rather is due to the effects of a complex mixture. These findings may be useful in future studies concerning green tea as a cancer preventive agent.

DNA fingerprinting of Australian isolates of Mycobacterium avium subsp paratuberculosis using IS900 RFLP.

OBJECTIVES: To evaluate additional restriction enzymes for IS900 RFLP of Mycobacterium avium subsp paratuberculosis and examine the genetic diversity among Australian isolates for epidemiological studies of Johne's disease. DESIGN AND PROCEDURE: Seventy-one isolates of M paratuberculosis from cattle, sheep, goat, alpaca and rhinoceros in six Australian States and the Northern Territory, reference strains and reference DNA from previously characterised strains were tested for genetic variation. Bst EII, Pvu II and Pst I restriction enzymes were used, and four others (Bam HI, Alu I, Xho I and Dra I) were assessed for their ability to detect polymorphisms. Multiple isolates from some animals were tested. RESULTS: Bam HI, was the most effective enzyme for identifying polymorphisms (12 types), followed by Bst EII (11 types). Both Pvu II and Pst I were relatively ineffectual. Fifteen different types were identified, 12 in clinical isolates. Most isolates were cattle (C) strains and fell into the C1 (n = 28) and C3 (n = 32) groupings. All isolates from alpaca were type C1, and bovine isolates were commonly C1 (n = 15) or C3 (n = 28). All of the sheep were infected with sheep (S) strains; no S strains were identified in cattle. Two of six isolates from one animal had single band differences. CONCLUSION: The epidemiological features of M paratuberculosis in Australia are similar to those reported in New Zealand, where cattle and sheep are commonly infected with different strains. However, because of the lack of polymorphism identified within the major groups, it is unlikely that DNA fingerprinting will have a significant role in epidemiological studies of Johne's disease, unless an unusual strain in being studied.

Tuberculosis due to Mycobacterium bovis in the Australian population: DNA typing of isolates, 1970-1994.

SETTING: Bacteriologically confirmed cases of Mycobacterium bovis in the Australian population. OBJECTIVE: To evaluate the DNA fingerprinting techniques commonly used for M. bovis on isolates from humans and determine whether they were useful for determining the origin of human infection. DESIGN: M. bovis strains isolated between 1970 and 1994 were obtained from five Australian Reference Laboratories. Four DNA fingerprinting techniques, comprising Southern hybridisation with three different probes (the insertion sequence [IS]6110, the polymorphic guanine-cytosine-rich sequence [PGRS] and the direct repeat [DR]) and a PCR-based method (spoligotyping) were used. RESULTS: The PGRS, DR and IS6110 RFLP methods identified 32, 22 and 14 different types respectively from the 45 isolates available. Spoligotyping identified 18 different types. When all methods were combined 41 different strains were identified. Clear differences were found between many isolates from Australian-born patients and those from patients born overseas. CONCLUSIONS: The PGRS RFLP method was the most effective method for typing the human strains, but a combination of methods is recommended for maximum sensitivity. Most Australian-born patients that had worked in the meat and livestock industries were infected with strains similar to those that are commonly found in Australian cattle, confirming the occupational risk in these industries. Patients born overseas were typically infected with strains genetically different from those of patients born in Australia. This suggests that patients born overseas identified with M. bovis were presenting with reactivation of infection acquired outside Australia.

Long-term effects of feeding gossypol and vitamin E to dairy calves.

Male Holstein calves were used to test the effect of feeding 400 mg of free gossypol/kg of diet and to determine whether vitamin E could counteract gossypol toxicity. Fifty-two calves were allotted to treatments as follows: 1) soybean meal-based starter; 2) cottonseed meal-based starter; 3) cottonseed meal-based starter + 2000 IU of vitamin E/d per calf, and 4) cottonseed meal-based starter + 4000 IU of vitamin E/d per calf. Vitamin E supplementation (treatments 3 and 4) improved weight gain and feed intake over calves on treatment 1. Gossypol concentrations in plasma were higher in calves on treatments 2, 3, and 4 than in calves on treatment 1; however, no differences were observed among animals receiving the three cottonseed meal diets. Hemoglobin and hematocrit were decreased in calves receiving treatment 2, and vitamin E supplementation counteracted this effect (treatments 3 and 4). Plasma alpha-tocopherol concentrations were not affected by gossypol intake and followed the vitamin E supplementation pattern During the experimental period, 10 calves died, six from treatment 2 and two each from treatments 3 and 4. Necropsy findings from 4 of 10 calves were suggestive of gossypol toxicity. Histopathological examination revealed centrilobular necrosis in the liver and atrophy and vacuolation of cardiocytes. Feeding cottonseed meal caused death of some calves with gossypol related toxicity signs, but did not decrease plasma alpha-tocopherol; however, vitamin E supplementation increased performance and may have conferred some protection against gossypol toxicity.

Effects on performance, tissue integrity, and metabolism of vitamin E supplementation for beef heifers fed a diet that contains gossypol.

We conducted an experiment for 112 d with yearling beef heifers to evaluate the effects of cottonseed meal (CSM) fed with various concentrations of vitamin E on hematological and tissue components. Heifers were assigned randomly to four treatments, with eight heifers per treatment. The treatments consisted of the following dietary supplements: 1) CON, based on soybean meal with 30 IU vitamin E/kg; 2) GOS, based on CSM with 30 IU vitamin E/kg; 3) G+2E, based on CSM with 2,000 IU vitamin E x animal(-1) x d(-1); and 4) G+4E, based on CSM with 4,000 IU vitamin E x animal(-1) x d(-1). Supplements based on CSM provided 4.5 g of free and 50.5 g of total gossypol x animal(-1) x d(-1). The total gossypol present in the supplements was 29.1% of the negative isomer (-) and 70.9% of the positive isomer (+). Blood samples were collected at the start of the experiment and every 2 wk thereafter up to 16 wk. There was a time x treatment interaction (P<.01) for plasma alpha-tocopherol ( alpha-T) concentration; however, feeding gossypol did not decrease plasma alpha-T. Weight gain, retinol palmitate, retinol, beta-carotene (beta-C), hemoglobin, and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P<.05) in gossypol-fed animals; however, vitamin E supplementation lowered EOF (P<.05). Heifers fed the supplements GOS, G+2E, and G+4E had greater (P<.01) plasma (-)-, (+)-, and total gossypol than heifers fed CON from Collection 2 to the end of the experiment. There was a treatment effect (P<.05) on vitamin E and gossypol concentrations in different tissues, with no effect (P>.05) for trace minerals (Cu, Zn, Fe, and Se). Vitamin E concentration in tissue increased with increased dietary supplementation of vitamin E. In heart and neck muscle, (-)-gossypol was greater (P<.05) than (+)-gossypol, but the reverse was true for liver. Gossypol decreased in vitro lipid peroxidation of liver homogenate in tissues. Gossypol deposition in tissue was liver > heart > muscle. In summary, gossypol from CSM did not decrease concentrations of antioxidant vitamins, including alpha-T, vitamin A, and beta-C, or have any detrimental effect on performance of beef heifers.

Reproductive effects of feeding gossypol and vitamin E to bulls.

An experiment was conducted to determine the effects of long-term feeding of cottonseed meal on the reproductive traits of Holstein bulls. Holstein bulls approximately 6 mo of age were placed on the following treatments: 1) soybean meal + corn (CON); 2) cottonseed meal + corn (GOS); and 3) cottonseed meal + 4,000 IU vitamin E x bull(-1) x d(-1) (G+4E). The GOS and G+4E diets were formulated to supply 14 mg of free gossypol x kg(-1) BW x d(-1). These bulls had been in a previous experiment that evaluated the effects of feeding the same type of diets, but from 2 wk to 6 mo. of age. Percentage of motility, percentage of normal and live sperm, and daily sperm production were less (P<.05) in the GOS than in the other two treatments. Percentages of primary abnormalities and abnormal midpieces were greater (P<.05) in the GOS group than in the other two groups. At 12 and 16 mo. of age, bulls were given two assessments for sex drive traits. Bulls that received gossypol exhibited less sexual activity (P<.05) at the first test than bulls in other treatments. Vitamin E supplementation in bulls that received gossypol improved the number of mounts in the first test and the time to first service in the second test. There was a trend of gossypol to decrease and vitamin E to improve libido score. The results of the GOS first libido test may indicate lack of sexual maturity, which agrees with sperm production data. At the time of first test (12 mo. of age), none of GOS, two of CON, and six of G+4E bulls had reached puberty on the basis of experimental protocol. Long-term feeding of gossypol to Holstein bulls negatively affected some reproductive traits; however, vitamin E supplementation countered these adverse effects and even improved these traits.

Long-term effects of gossypol and vitamin E in the diets of dairy bulls.

Long-term effects of the inclusion of cottonseed meal in the diet on hematological and tissue parameters of Holstein bulls were investigated. Twenty-four Holstein bulls that were approximately 6 mo of age received the following treatments for 10 mo: 1) soybean meal plus 30 IU of vitamin E/kg, 2) cottonseed meal plus 30 IU of vitamin E/kg, and 3) cottonseed meal plus 4000 IU of vitamin E/d per bull. Treatments 2 and 3 were formulated to supply 14 mg of free gossypol/kg of body weight per d. Average daily gain, total gain, and final body weights were not affected by treatment. The osmotic fragility of erythrocytes was greater during all collection periods for bulls on treatments 2 and 3 than for bulls on treatment 1. The inclusion of 4000 IU of vitamin E/d per bull did not reduce the increase in the osmotic fragility of erythrocytes that was caused by gossypol. Bulls on treatment 3 had higher plasma alpha-tocopherol concentrations than did bulls on treatments 1 and 2. Vitamin E supplementation did not affect gossypol concentrations in plasma or tissue. The highest gossypol concentrations were found in the liver followed by the heart and testis. In vitro lipid peroxidation of tissue indicated that gossypol acts as an antioxidant in lipid peroxidation systems, and its role as an antioxidant may be dependent on dose or tissue. Cottonseed meal in the diets of bulls did not affect growth or vitamin E status.

Induction of apoptosis in two mammalian cell lines results in increased levels of fructose-1,6-bisphosphate and CDP-choline as determined by 31P MRS.

Programmed cell death or apoptosis was induced in human promyelocytic leukemia (HL-60) and Chinese hamster ovary (CHO-K1) cells using several cytotoxic drugs that have different modes of action, including camptothecin, ceramide, chelerythrine, etoposide, farnesol, geranyl geraniol, and hexadecylphosphocholine. The consequent changes in cellular metabolism were monitored using 31P MRS measurements on intact cells and cell extracts. Cells undergoing programmed cell death exhibited characteristic changes in the levels of glycolytic and phospholipid metabolites. The most significant changes were increases in the concentration of the glycolytic intermediate, fructose-1,6-bisphosphate and in the concentration of CDP-choline, which is an intermediate in phosphatidylcholine biosynthesis. In HL-60 cells, the increase in fructose-1,6-bisphosphate levels could be explained by depletion of cellular NAD(H) levels. All of the agents used to induce apoptosis caused the accumulation of CDP-choline. Since the resonances of this compound occur in a relatively well resolved region of tissue spectra, it could provide a marker for apoptosis that would allow the noninvasive detection of the process in vivo using 31P MRS measurements.

Effects of supplemental vitamin E and canola oil on tissue tocopherol and liver fatty acid profile of finishing swine.

We conducted a 4 x 3 factorial experiment with finishing pigs for 6 wk to evaluate effects of dietary canola oil and vitamin E on vitamin E status and liver fatty acid profile. Treatments consisted of four supplemental levels of vitamin E (0, 50, 125, and 200 mg/kg) and three of canola oil (0, 5, and 10% of the diet). Serum was collected each week and tissue samples at d 42. Dietary canola oil (P = .02) and vitamin E (P < .001) increased serum alpha-tocopherol. Serum alpha-tocopherol reached a plateau at d 35 of vitamin E and canola oil supplementation. An interaction was observed between canola oil and vitamin E (P = .02) for liver alpha-tocopherol. Liver alpha-tocopherol was greater in pigs fed diets with 10% canola oil and supplemented with 125 or 200 mg/kg of vitamin E than in pigs fed diets with 0 and 5% canola oil. An interaction also occurred between canola oil and vitamin E (P = .01) for alpha-tocopherol in the gluteus medius and obliquus capitis caudalis muscles. A greater magnitude of increase in muscle alpha-tocopherol was observed in pigs fed diets with no canola oil than in pigs fed diets with 5 and 10% canola oil. Highest alpha-tocopherol was in liver, followed by obliquus capitis caudalis and then gluteus medius. Inclusion of 5 or 10% dietary canola oil decreased the amount of saturated fatty acids by 4.1 and 13.5%, increased monounsaturated fatty acids by 10.9 and 39.3%, respectively, and had no effect (P > .10) on total polyunsaturated fatty acids. Canola oil increased linoleic acid [18:2(n-6)] (quadratic, P = .05) and linolenic acid [18:3(n-3)] (linear, P < .001) while decreasing arachidonic acid [20:4(n-6)] and docosadienoic acid (20:2) linearly (P < .001 and P = .02, respectively). Dietary canola oil and vitamin E increased serum and tissue alpha-tocopherol; canola oil increased monounsaturated and decreased saturated fatty acids in liver.

Vitamin E supplementation of cattle and shelf-life of beef for the Japanese market.

Feeder steers (n = 84) were stratified into four weight groups to provide slaughter groups so that product that had been in vacuum packages at 0 to 2 degrees C for 40, 60, 80, or 100 d postmortem could be simultaneously evaluated. Each of the four groups was randomly divided into three subgroups so that vitamin E could be supplemented in the diet at rates of 0, 1,000, or 2,000 (E0, E1000, and E2000, respectively) IU.steer-1.d-1 for 100 d. After slaughtering, chilling, and fabricating, one ribeye-roll and one strip loin from each carcass was transported to the university laboratory for analyses, whereas the paired subprimals were transported to Japan. Based on metmyoglobin formation and lipid oxidation, strip loin steaks deteriorated at a faster rate during retail-display than did ribeye steaks. Steaks from subprimals that were stored for 100 d had inferior (P < .05) retail-display characteristics and a shorter (P < .05) caselife than steaks from the other storage periods. alpha-Tocopherol levels in longissimus muscle were lower (P < .05) for E0 than for E1000 and E2000 (3.51, 5.54, and 6.10 micrograms/g of tissue, respectively). Supplementing cattle with vitamin E resulted in steaks that exhibited superior lean color, less surface discoloration, more desirable overall appearance, and less lipid oxidation during retail display than control steaks; minimal differences were observed between E1000 and E2000 steaks. Steaks from cattle supplemented with vitamin E were preferred over control steaks by 91% of Japanese survey participants (n = 10,941), and 58% of all participants identified muscle color as the most important factor in selecting beef products.

Mapping of oxygen tension and cell distribution in a hollow-fiber bioreactor using magnetic resonance imaging.

We mapped the distribution of dissolved oxygen and mammalian cells in a hollow-fiber bioreactor (HFBR) using (19)F NMR T(1) relaxation time imaging measurements on an infused perfluorocarbon probe molecule and diffusion-weighted (1)H NMR imaging of water. This study shows how cell density influences dissolved oxygen concentration in the reactor and demonstrates that NMR can play an important role in defining the biochemical engineering parameters required for optimization of HFBR design and operation.

Effects of vitamin E on mammary and blood leukocyte function, with emphasis on chemotaxis, in periparturient dairy cows.

OBJECTIVE: To determine the effect of vitamin E supplementation on the immune system of dairy cows. DESIGN: The following immune parameters were followed: production of chemotactic factors and superoxide by mammary macrophages and chemotactic responsiveness of blood neutrophils. ANIMALS: 16 healthy Holstein dairy cows. PROCEDURE: Dairy cows were assigned to 1 of 2 experimental groups: control (no vitamin E supplementation) and vitamin E supplemented. Supplementation of vitamin E started 4 weeks before and continued up to 8 weeks after parturition, and included oral supplementation of vitamin E at the rate of 3,000 IU/cow/d. In addition, the same group of cows received 1 injection of vitamin E (5,000 IU) 1 week prior to the expected date of parturition. Blood samples were collected weekly throughout the experimental period. RESULTS: Vitamin E supplementation enhanced by 30 to 83% (P < 0.05) chemotactic responsiveness of blood neutrophils beginning 2 weeks before to 4 weeks after parturition, compared with controls. There were no differences in production of superoxide or chemotactic factors by mammary macrophages between control and vitamin E-supplemented cows. CONCLUSIONS: Vitamin E supplementation prevents the periparturient inhibition of neutrophil chemotaxis. It is unlikely that vitamin E affects directly the function of mammary macrophages.

alpha-Tocopherol concentrations in milk and plasma during clinical Escherichia coli mastitis.

Eighteen cows were challenged by intramammary infusion with Escherichia coli 727 to determine the effects of acute clinical mastitis on alpha-tocopherol concentrations in plasma and milk. Cows were fed diets supplemented with 1000 IU of vitamin E/d from calving through the experimental period. At challenge, geometric mean DIM was 33 d. Each mammary quarter was diagnosed with an IMI and clinical mastitis at 24 and 48 h after challenge. The alpha-tocopherol concentrations in milk from challenged quarters were approximately 60% greater by 24 and 48 h after challenge than concentrations at prechallenge and 168 h postchallenge. Plasma alpha-tocopherol concentrations did not change after intramammary challenge. The alpha-tocopherol in plasma and milk was correlated at 48 and 168 h postchallenge but not at prechallenge or 24 h postchallenge. Milk alpha-tocopherol and SCC were correlated positively across all sample periods. Milk fat and milk alpha-tocopherol concentrations were correlated at each sample period except 24 h postchallenge. Increases in milk alpha-tocopherol during clinical mastitis were not correlated to milk production, DMI, or BSA concentration in milk. Changes in milk alpha-tocopherol concentration during clinical mastitis were similar to the dynamics of milk SCC.

Growth and fresh meat quality characteristics of pigs supplemented with vitamin E.

Crossbred pigs (n = 30) were fed to determine the influence of supplementation with vitamin E on growth and slaughter characteristics of swine and on the quality characteristics of fresh pork. Pigs received either a control diet containing no vitamin E (CON) or a diet formulated to contain 100 mg of vitamin E/kg feed (VITE). During 84 d of feeding, feed intake and weight gain were measured every 2 wk. After the feeding period, pigs were slaughtered and the loin from the left side of each carcass was removed 4 d after death. Alpha-Tocopherol concentration and proximate composition of the longissimus muscle were determined. Loins were sliced into 10-cm sections and stored under vacuum (2 degrees C) for 0, 14, 28, and 56 d. After storage, loins were sliced into 2.54-cm chops, wrapped in polyvinyl chloride film and stored in a retail case (2 to 4 degrees C) for 5 d. Thiobarbituric acid (TBA) values, Hunter L, a, and b values, total plate counts, pH, purge loss, drip loss, cook loss, taste panel characteristics, and visual panel characteristics were evaluated. Growth traits, slaughter characteristics, and proximate composition did not differ (P > .05) between dietary treatment groups. Alpha-Tocopherol concentrations were greater (P < .05) and TBA values during extended retail display were less (P < .05) for VITE chops than for CON chops. Overall palatability ratings were more desirable (P < .05, at 14 d of vacuum storage) for VITE chops than for CON chops. Color measurements, sensory characteristics, total plate counts, pH, purge loss, drip loss, and cook loss were not influenced (P > .05) by vitamin E supplementation. These results indicated that at the tissue alpha-tocopherol concentrations of the present study, vitamin E supplementation of the growing-finishing diet of hogs reduced lipid oxidation in fresh pork but did not influence pork color or tissue drip loss.

Titration of fresh meat color stability and malondialdehyde development with Holstein steers fed vitamin E-supplemented diets.

Pigment and lipid oxidations were investigated in longissimus lumborum (LL), semimembranosus (SM), and gluteus medius (GM) from Holstein steers fed four doses of vitamin E (64 [control], 295, 550, or 2,173 IU/d) for two durations (42 or 126d). Vitamin E dose did not affect (P = .30) carcass quality or yield characteristics. The LL was stored in vacuum packages at 4 degrees C for 14, 28, and 56 d, and GM and SM were stored for 14 d. Increments of dose and duration of vitamin E supplementation increased (P < .001) alpha-tocopherol concentration in blood plasma and in these muscles. During simulated retail display, accumulations of metmyoglobin (METMB) and thiobarbituric acid reactive substances (TBARS) were greater (P < .01) in beef from control than in beef from supplemented steers. In cubic models, muscle alpha-tocopherol accounted for 79% of the variation in TBARS and 66% of the variation in METMB. Color display life, calculated by the METMB threshold method, revealed fewer dose and duration effects of vitamin E than were evident following analysis of variance of the METMB responses. Across durations and muscles, color display-life of fresh beef calculated by the METMB threshold method was extended (P < .05) .9 to 1.8 d by vitamin E supplementation (P < .05). Storage for 28 or 56 d caused only a slight decline (P < .001) in LL alpha-tocopherol concentration but diminished (P < .05) vitamin E effects on color display-life. Although the ranking of alpha-tocopherol accumulation was GM > SM > LL, the color display-life ranking of these muscles across vitamin E treatments was LL > SM > GM.