Levels Of Dietary Vitamin Research Articles

Effect of Dietary Vitamin E on Growth, Fecundity, and Leukocyte Count in Goldfish (Carassius auratus)

The effects of different levels of dietary vitamin E (0, 100, 200, 300, and 600 mg/kg diet) on growth, gonad weight, fecundity, and leukocyte count were studied in goldfish (Carassius aura- tus) for 120 days. Fish fed the 300 mg vitamin E/kg diet had the best feeding rate, weight gain, and specific growth rate. Fish fed the control diet lacking vitamin E began to develop gonads on day 60 and spawned only once, while those fed diets containing vitamin E began to develop gonads on day 40 and spawned twice. Females fed the 300 mg vitamin E/kg diet had signifi- cantly (p<0.01) heavier gonads and a higher number of eggs with better hatchability than those fed other diets. The second spawn was significantly (p<0.01) more prolific than the first in all groups. Egg weight and diameter and larvae weight and length were significantly (p<0.05) high- er in fish fed 300 mg vitamin E than in fish fed the control diet but did not differ from other vita- min E treatments. Lymphocyte and monocyte populations were highest in fish fed 300 mg vita- min E. Thus, 300 mg vitamin E/ kg diet is the optimum level for improving reproduction and immune response in C. auratus. The probable mechanism for the action of vitamin E on growth and reproduction is discussed.

Dietary vitamin mix levels influence the ossification process in European sea bass (Dicentrarchus labrax) larvae

The influence of dietary vitamins on growth, survival, and morphogenesis was evaluated until day 38 of posthatching life in European sea bass larvae (Dicentrarchus labrax). A standard vitamin mix (VM), at double the concentration of the U.S. National Research Council's recommendations, was incorporated into larval feeds at 0.5%, 1.5%, 2.5%, 4.0%, and 8.0% to give treatments VM 0.5, VM 1.5, VM 2.5, VM 4.0, and VM 8.0, respectively. The group fed the VM 0.5 diet all died before day 30. At day 38, the larvae group fed VM 1.5 had 33% survival, while the other groups, with higher vitamin levels, showed at least 50% survival. The higher the percentage VM in the diet, the lower the percentage of column deformities. High dietary vitamin levels positively influenced the formation of mineralized bone in larvae: the higher the dietary vitamin level, the higher the ossification status. In the larvae group fed at the highest vitamin levels, we observed a temporal sequence of coordinated growth factor expression, in which the expression of bone morphometric protein (BMP-4) preceded the expression of IGF-1, which stimulated the maturation of osteoblasts (revealed by high osteocalcin expression levels). In groups fed lower proportions of vitamins, elevated proliferator peroxisome-activated receptors (PPAR-gamma) expression coincided with low BMP-4 expression. Our results suggest that high levels of PPAR-gamma transcripts in larvae-fed diets with a low VM content converted some osteoblasts into adipocytes during the first two weeks of life. This loss of osteoblasts is likely to have caused skeletal deformities.

Use of vitamin C as an immunostimulant. Effect on growth, nutritional quality, and immune response of Labeo rohita (Ham.)

Teleost fish lack the enzyme for endogenous synthesis of ascorbic acid (AA), an essential micronutrient for fish. The aim of this study was to examine the effect of higher levels of dietary vitamin C on growth, nutritional quality, and immunomodulation in the Indian major carp, rohu (Labeo rohita). Four groups of L. rohita were fed experimental diets containing either no vitamin C (control) or supplemented with vitamin C at 500 mg kg(-1) (Exp-1), 1000 mg kg(-1) (Exp-2), or 1500 mg kg(-1) (Exp-3) for 60 days. Growth parameters (NWG, ADG, and SGR), serological parameters (TSP, TSA, TSG, and A:G), haematological parameters (TLC, TEC, Hct, MCV, and MCH), and different non-specific immunological parameters (PR, PI, respiratory burst activity, and bactericidal activity) were evaluated during the experimental trial. Fish fed a vitamin C-supplemented diet showed higher specific growth rate (SGR) up to 1000 mg kg(-1) compared with control fish. Different haematological and serological parameters along with non-specific immune parameters were influenced by vitamin C supplementation. Among the non-specific immune parameters phagocytic activity (PR and PI) and respiratory burst activity (NBT cells) were significantly (P < or = 0.05) enhanced by increasing doses of vitamin C supplementation. Higher levels of dietary vitamin C significantly (P < or = 0.05) enhanced protection against Aeromonas hydrophila (AH1) infection compared with controls. Results from this study help to establish the beneficial effect of vitamin C on growth and immunmodulation in rohu (L. rohita).

Bronchodilators

Vitamin D is an essential hormone that regulates many different functions in vertebrates and can have a protective effect against various disease conditions. Providing exotic pets appropriate access to vitamin D, through the diet, ultraviolet B (UVB) exposure, or a combination of both, is important for veterinarians and exotic pet owners to consider. Although it is commonly thought that most animals derive the vitamin D they need through their diet, there are a number of species that appear to benefit more from UVB exposure. In addition, there has been minimal study to investigate appropriate dietary levels of vitamin D for many of our exotic pets. Although the recommendation of providing UVB lighting has been primarily limited to captive reptiles, research with other species (e.g., birds and small mammals) suggests that these animals may also benefit from this type of lighting. However, the provision of UVB is not without its potential side effects. The purpose of this article is to review the important roles of vitamin D in animals, the different methods animals use to acquire this hormone, the potential clinical signs associated with hypovitaminosis or hypervitaminosis D, the role of artificial UVB lighting in the synthesis of vitamin D, and the potential side effects associated with UVB radiation.

Dietary levels of vitamin A and D may influence the development of cancer

Dietary levels of vitamin A and D may influence the development of cancer

EFFECTS OF VITAMIN E ON ANTIOXIDANT ENZYME ACTIVITIES AND FATTY ACID COMPOSITIONS IN JUVENILE ABALONE HALIOTIS DISCUS HANNAI INO

A 240-day feeding trial was conducted in a recirculated water system to investigate the effects of dietary vitamin E on the activities of antioxidant enzymes (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidase, GPX) and the composition of fatty acids in abalone, Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 0.71 ± 0.00 g; initial shell length: 15.49 ± 0.04 mm) were fed to satiation one of three semipurified diets containing 0, 50, and 5,000-mg/kg vitamin E, respectively. Abalone were sampled on the 120th day and the 240th day, respectively. There were no significant differences in activities of CAT and SOD in soft body of abalone fed with different levels of dietary vitamin E for 120 days (P > 0.05), but significantly higher activity of GPX was found with 5,000-mg/kg dietary vitamin E (P < 0.05). Activities of CAT and GPX were significantly elevated by dietary vitamin E on the 240th day. The lowest value of 18:1n-9, 18:2n-6 and the highest value of 22:6n-3 in soft body were found with 50 mg/kg dietary vitamin E supplement on the 120th day. On the 240th day, the content of monounsaturated fatty acids (MUFA) in abalone with 50-mg/kg dietary vitamin E supplement was significantly higher than those in the other two treatments (P < 0.05). There were no significant effects of dietary vitamin E on the content of polyunsaturated fatty acids (PUFA) in abalone during the two sampling periods (P > 0.05). In conclusion, 50-mg/kg dietary vitamin E supplement elevated the activities of antioxidant enzymes and could protect MUFA from peroxidation damage. Excessive dietary vitamin E (5,000 mg/kg) did not serve as an antioxidant any more, but tended to be a pro-oxidant in the soft body of abalone.

The Effect of Dietary Vitamin E (-Tocopherol) Level on the Lipid, Essensial Fatty Acid Level and the Hatching Rate of Catfish, Clarias batrachus Linn.

&lt;p class="MsoNormal" style="text-align: justify;"&gt;&lt;span lang="in" xml:lang="in"&gt;This experiment was conducted to evaluate the dietary level of vitamin E (&lt;/span&gt;&lt;em&gt;&lt;span lang="in" xml:lang="in"&gt;a&lt;/span&gt;&lt;/em&gt;&lt;em&gt;&lt;span lang="in" xml:lang="in"&gt;-tocopherol&lt;/span&gt;&lt;/em&gt;&lt;span lang="in" xml:lang="in"&gt;) on the lipid, essential fatty acid level and the hatching rate of catfish, &lt;em&gt;Clarias batrachus&lt;/em&gt; Linn. Five experimental diets with isoenergy and isonitrogen, but different vitamin E (&lt;/span&gt;&lt;em&gt;&lt;span lang="in" xml:lang="in"&gt;a&lt;/span&gt;&lt;/em&gt;&lt;em&gt;&lt;span lang="in" xml:lang="in"&gt;-tocopherol&lt;/span&gt;&lt;/em&gt;&lt;span lang="in" xml:lang="in"&gt;) level were used in this experiment. Dietary vitamin E levels are 18, 114, 210, 308 and 416 mg/kg diet respectively.&lt;span&gt; &lt;/span&gt;Fish with body weight of 18,55 &lt;/span&gt;&lt;span lang="in" xml:lang="in"&gt;a&lt;/span&gt;&lt;span lang="in" xml:lang="in"&gt; 5,11 g per fish, fed on the experimental diets at satiation, for six months.&lt;span&gt; &lt;/span&gt;The vitamin E, the lipid and the n-6 and n-3 fatty acid level of egg increase as the dietary vitamin E level of broodstock diet increase. However, the ratio of n-6/n-3 fatty acid of egg produced&lt;span&gt; &lt;/span&gt;by treatment 210 mg vitamin E/kg diet was higher than that of other treatments, which finally produced the highest hatching rate of egg (p&amp;lt;0,05).&lt;/span&gt;&lt;/p&gt;&lt;p class="MsoNormal" style="text-align: justify; line-height: 150%;"&gt;&lt;span lang="in" xml:lang="in"&gt;Key words : Vitamin E (&lt;/span&gt;&lt;em&gt;&lt;span lang="in" xml:lang="in"&gt;a&lt;/span&gt;&lt;/em&gt;&lt;em&gt;&lt;span lang="in" xml:lang="in"&gt;-tocopherol&lt;/span&gt;&lt;/em&gt;&lt;span lang="in" xml:lang="in"&gt;), reproduction, catfish (&lt;em&gt;Clarias batrachus&lt;/em&gt; Linn.)&lt;/span&gt;&lt;/p&gt;

Effects of dietary fish oil and vitamin E supplementation on canine lymphocyte proliferation evaluated using a flow cytometric technique

Lymphocyte proliferation and peripheral blood mononuclear cell (PBMC) production of PGE 2 were assayed in 15 healthy dogs fed a basal diet supplemented with either sunflower oil (Group Sunflower oil), sunflower oil and menhaden fish oil (Group Fish oil), or sunflower oil and menhaden fish oil plus α-tocopherol acetate for 12 weeks (Group Fish oil + E). Lymphocyte proliferation was determined by a flow cytometric technique utilizing the fluorochrome carboxyfluorescein diacetate succinimidyl ester (CFSE). The PBMC supernatant PGE 2 concentration was assayed using a competitive enzyme-linked immunoassay. Group Fish oil had a significant decrease in lymphocyte proliferation at week 12. PBMC production of PGE 2 was decreased in all three groups but only significantly reduced in groups receiving fish oil supplementation. Based on these results, this level of fish oil supplementation appears to suppress the lymphoproliferative response in healthy, young dogs but this response can be attenuated by high levels of dietary vitamin E supplementation. Furthermore, fish oil-induced reduction in lymphocyte proliferation appears to manifest through a PGE 2-independent mechanism and is not associated with increased lipid peroxidation.

Vitamin requirements: is there basis for re-evaluating dietary specifications?

There has been little work conducted over the last 40 years on estimating vitamin requirements of poultry, and so consequently NRC (1994) values are still often quoted as standards. A review of this information indicates many values are estimates, or extrapolated from comparable species, or as with broiler breeders, simply not given. The current concern related to formulating vitamin levels in poultry diets is the assumption that change in genetic potential of layers and meat birds necessitates re-evaluation, and that parameters for assessing needs are now more complex than simple production metrics as used previously. Unfortunately information on maintenance needs for vitamins is lacking, and while there is now information available on vitamin content of eggs, comprehensive details of the vitamin level in poultry meat products is surprising lacking. With unprecedented egg output of modern layer strains, and ever improving feed efficiency in meat birds, vitamin intake per unit of output is continually declining. For layers the estimate is around a 1% yearly decline in vitamin intake per egg produced, while for meat birds there has been a 0.6-0.8% yearly decline per kg body gain. This reduced intake of vitamins is the basis for improved performance in layers and meat birds fed a higher than normal level of vitamins. However, an even more important basis for reevaluating vitamin needs is change in measurement criteria. Many vitamins and especially the fat soluble vitamins accumulate in eggs and meat in proportion to diet inclusion. Development of vitamin enriched designer poultry products therefore dictates elevated feeding levels of vitamins. Co-incidentally, increased levels of vitamin E in poultry products has led to the realization that increased antioxidant capacity of these tissues enhances shelf life and appearance. Of greatest impact in reevaluating diet vitamin specifications has been the effect of these nutrients on bird health and in particular immune response. For example dietary levels of vitamin E far in excess of NRC (1994) requirements have been shown to positively impact immune response in all ages of bird and also the performance of heat-stressed birds. Expectations of ever increasing performance dictate the need for continual reevaluation in determining vitamin levels within diet formulations as detailed in recent publications on optimum vitamin nutrition of poultry to improve health, welfare, performance and the quality of poultry products.

Effect of Dietary Supplementation of Vitamins A, D3, E, and C on Yearling Rice Field Eel, Monopterus albus: Serum Indices, Gonad Development, and Metabolism of Calcium and Phosphorus

Abstract.— The objective of this study was to determine the effect of dietary vitamins A, D3, E, and C on the gonad development, lipid peroxidation, and immune response of yearling rice field eel, Monopterus albus. A 6‐wk feeding trial was designed according to an L16(45) orthogonal design, in which four vitamins, each at four supplementation levels, were arranged. Sixteen diets were mixed with the different vitamin levels and randomly assigned to 16 groups of fish. Increasing dietary vitamin E supplementation level significantly (P ≤ 0.05) increased the gonadosomatic index and lowered the serum content of malondialdehyde of rice field eel. Increasing dietary vitamin A and C levels also showed similar effect, but the differences were not statistically significant. Serum immunoglobulin M content increased significantly (P ≤ 0.01) as dietary vitamin C supplementation levels increased. The concentrations of calcium in bones showed significant (P ≤ 0.05) trend with vitamin D3 and A supplementation levels, but the bone phosphorus content was not affected by the dietary vitamin levels.

The Interactive Effect of Dietary Protein and Vitamin Levels on the Depression of Gonadal Development in Growing Male Rats Kept under Disturbed Daily Rhythm

The purpose of this study was to clarify the effects of nutrients on the gonadal development of male rats kept under constant darkness as a model of disturbed daily rhythm. The present study examined protein and vitamins, and their interactions. This study was based on three-way ANOVA; the three factors were lighting conditions, dietary protein and dietary vitamins, respectively. The levels of dietary protein were low or normal: 9% casein or 20% casein. The levels of dietary vitamins were low, normal or high: 1/3.3 of normal (AIN-93G diet) content, normal content, or three times the normal content, respectively. Other compositions were the same as those of the AIN-93G diet, and six kinds of experimental diet were prepared. Four-week-old rats (Fischer 344 strain) were kept under constant darkness or normal lighting (12-h light/dark cycle) for 4 wk. After 4 wk, the gonadal weights and serum testosterone content were evaluated. In the constant darkness groups (D-groups), the low-protein diet induced reduction of gonadal organ weights and serum testosterone concentrations. This reduction of gonadal organ weights was exacerbated by progressively higher levels of dietary vitamins. In the case of a normal-protein diet, the depression of gonadal development was not accelerated by high-vitamin intake. In the normal lighting groups (N-groups), the low-protein and high-vitamin diet slightly depressed gonadal development. These results suggest that the metabolism of protein and vitamins is different in rats being kept under constant darkness, and that excess dietary vitamins have an adverse effect on gonadal development in rats fed a low-protein diet.

Generation of superoxide and singlet oxygen from α-tocopherolquinone and analogues

Three potential routes to generation of reactive oxygen species (ROS) from α-tocopherolquinone (α-TQ) have been identified. The quinone of the water-soluble vitamin E analogue Trolox C (Trol-Q) is reduced by hydrated electron and isopropanol α-hydroxyalkyl radical, and the resulting semiquinone reacts with molecular oxygen to form superoxide with a second order rate constant of 1.3 × 108 dm3/mol/s, illustrating the potential for redox cycling. Illumination (UV-A, 355 nm) of the quinone of 2,2,5,7,8-pentamethyl-6-hydroxychromanol (PMHC-Q) leads to a reactive short-lived (ca. 10− 6 s) triplet state, able to oxidise tryptophan with a second order rate constant greater than 109 dm3/mol/s. The triplet states of these quinones sensitize singlet oxygen formation with quantum yields of about 0.8. Such potentially damaging reactions of α-TQ may in part account for the recent findings that high levels of dietary vitamin E supplementation lack any beneficial effect and may lead to slightly enhanced levels of overall mortality.

Effects of high‐level dietary B‐vitamins on performance, body composition and tissue vitamin contents of growing/finishing pigs

Forty-eight growing pigs were randomly assigned to five dietary groups and penned individually. They received a diet based on barley, wheat, corn and soya bean meal according to requirement. The experimental groups were supplemented with 400% or 800% of vitamins B(2), B(6) and pantothenic acid, or 400% or 800% of biotin, while all other vitamins were administered according to requirement. Growth performance, carcass characteristics, aspartate aminotransferase (AST), and content of vitamins in blood, liver and muscles were recorded. Growth performance showed no influence of supplementation, while backfat thickness in the group with 800% B(2)/B(6)/pantothenic acid was significantly higher. Content of B(2) in blood, liver and muscle was similar in all groups. Content of B(6) in blood and liver showed significant differences according to supplementation. The content of vitamin B(6) in muscle in the experimental groups was significantly higher than that in the control group. The content of pantothenic acid in blood and muscle in the experimental groups was significantly higher, while in liver all groups were significantly influenced by the supplementation level. Biotin content in liver showed no influence, but the content in plasma was significantly higher in the experimental groups and the content in muscle was significantly higher according to supplementation. The activity of AST showed no significant influence of the dietary vitamin level, but it was obviously decreased in the groups supplemented with biotin. The findings indicate that the dietary supplementation of vitamin B(2), B(6), pantothenic acid and biotin could not improve performance, but the contents in blood, liver and muscle.

Effect of dietary vitamin E supplementation and feeding period on pork quality1

Feeding increased levels of dietary vitamin E can inhibit lipid oxidation. The aim of this study was to investigate the effect of levels of dietary alpha-tocopherol acetate (VE) and feeding duration on meat quality and lipid oxidation. Eighty-one pigs were allocated to 1 of 3 diets containing 40, 200, or 400 IU of VE/kg of feed, and each diet group was divided into 3 feeding periods (3, 6, or 9 wk). Carcass characteristics and meat quality were evaluated. Oxidative stability of fresh and cooked pork patties and pork chops was determined after chilled or frozen storage. Increasing dietary concentrations of VE did not affect any growth performance parameter. Drip loss, however, decreased (P < 0.05) with increased dietary VE levels. Moreover, an increased duration of VE feeding improved (P < 0.05) pH and drip loss. Less lipid oxidation (P < 0.05) was detected in fresh ground pork from pigs fed greater concentrations of VE after 4 d of storage. A greater (P < 0.05) resistance to oxidation in cooked ground pork was observed in pigs fed 200 or 400 IU of VE/kg at 2 and 6 d of storage. Fresh and cooked pork patty oxidation decreased (P < 0.05) linearly as feeding duration increased from 3 to 9 wk. After 6 mo of freezer storage, lipid oxidation of pork chops from pigs fed 200 or 400 IU of VE/kg was lower (P < 0.05) than for pigs fed 40 IU of VE/kg. Likewise, lipid oxidation of pork chops of pigs fed VE for an extended period of time (6 wk) was lower (P < 0.05) after 9 mo of storage. Fatty acid profiles of neutral lipid fraction of the LM became more unsaturated (P < 0.05) with added VE to the feed. These results indicate an increased intake of dietary VE concentration, and prolonged feeding of VE can improve drip loss and reduce lipid oxidation in ground pork and pork chops. This study suggests that supplementation with 200 IU of VE/kg of feed for 6 wk before market is beneficial in improving lipid stability and pork quality.

Supra dietary levels of vitamins C and E enhance antibody production and immune memory in juvenile milkfish, Chanos chanos (Forsskal) to formalin-killed Vibrio vulnificus

Juveniles of milkfish, Chanos chanos (Forsskal), were fed two independent supra dietary levels of vitamins C (500 and 1500 mg kg −1 feed, T1 and T2) and E (50 and 150 mg kg −1, T3 and T4). Milkfish fed diets with supra (in addition to the vitamins present in the control diet) and normal levels (T5 containing 90 and 1.2 mg of vitamins C and E, respectively, kg −1 of feed) of vitamins were immunized (ip) with formalin-killed Vibrio vulnificus (FKVV). Priming and booster antibody responses to the injected bacterin were significantly ( P < 0.05) better in the milkfish juveniles fed supra dietary levels. Survival response of the experimental fish fed supra dietary levels of vitamins (T1, T2 and T3) was significantly ( P < 0.01) better than that of the control set. Protective response against virulent bacterial challenge of the vaccinated fish fed vitamin-supplemented diets (T2 and T3) was better than the control (T5) and T1 and T4. Memory factor reflecting immunological memory was superior in the fish fed vitamin-supplemented diets. Diets supplemented with either 1500 mg of Vitamin C or 50 mg of Vitamin E kg −1 produced the best antibody responses, final survival and protective response upon challenge. No conclusive inferences could be drawn on the growth responses from the experiment.

Effect of dietary Vitamin E on the cloacal gland, foam and semen characteristics of male Japanese quail

This experiment was to investigate the effects of increasing the level of dietary Vitamin E (Vit. E) on cloacal gland size, foam production and semen characteristics of male Japanese quail ( Coturnix coturnix Japonica). One hundred and eighty male Japanese quail chicks (day old) were randomly distributed to three dietary treatments for a period of 25 weeks. Each treatment comprised of three replicates each containing 20 chicks. The basal diet contained 15 IU Vit. E/kg and the two experimental diets were supplemented with 150 and 300 IU Vit. E/kg (diets T 2 and T 3, respectively). DL α-tocopherol acetate was used as the source of Vit. E. All chicks were provided feed and water ad libitum. Foam characteristics, in terms of frequency of foam discharge (24 h), cloacal gland index and foam weight were significantly higher ( P < 0.05) in T 2 group. Body weight, testes weight (left and right) and plasma testosterone concentrations did not differ significantly. Semen characteristics (semen volume, sperm motility, % live sperm, % hatchability and sperm concentrations) did not differ significantly ( P > 0.05). Percentages of abnormal and dead spermatozoa were significantly ( P < 0.05) lower and fertility was higher ( P < 0.05) in the T 2 group. From this study, it can be concluded that moderate supplementation of dietary Vit. E may be beneficial for foam production, cloacal gland and improve the semen characteristics in male Japanese quail.

Poult Performance as Influenced by Age of Dam, Genetic Line, and Dietary Vitamin E

An experiment was conducted to measure the effects of age of dam, genetic line, and dietary levels of vitamin E on growth and immunocompetence of poults. Age of dam was defined as younger (in early egg production) and older (past peak production); line consisted of a commercial sire and dam line; and dietary vitamin E was supplemented into the diet at 10 and 300 IU/kg of feed. Traits measured included body, liver, gizzard, and yolk sac weights at hatch; BW and feed conversion to 9, 28, and 42 d; response to SRBC, Phaseolus vulgaris agglutinin-P, and Escherichia coli administered at 28 d of age; and response to a cold stress on d 5 posthatch. Differences among genetic lines were evident with growth greater for poults from the sire than from the dam line. Performance of poults from older dams was generally superior to that of poults from younger dams. The higher level of vitamin E resulted in a greater than 7-fold increase in blood plasma vitamin E and reduced mortality. There were interactions among the main effects in which the fitness of poults from younger dams was enhanced by the higher level of vitamin E and the effect of breeder age differed among genetic lines.

Memory Antibody Responses of Broiler and Leghorn Chickens as Influenced by Dietary Vitamin E and route of Sheep Red Blood Cell Administration

Influences of dietary levels of vitamin E fed to hens and their progeny, and routes of SRBC inoculation on antibody responses of diverse populations of chickens were studied. Populations were a commercial broiler sire line (C), 2 commercial broiler dam lines (A and B), and Leghorn lines selected for high (H) or low (L) antibody response to SRBC. Dams from lines A and B were fed diets supplemented with either 10 or 300 IU/kg of vitamin E, whereas dams from lines H and L received only the diet with 10 IU of vitamin E/kg. Progeny from matings of C males with A and B females as well as H and L females mated to males from their respective lines were hatched on the same day and fed diets supplemented with either 10 or 300 IU/kg of vitamin E. Breeders were the same age and eggs were incubated in the same machine. Chicks were inoculated on d 14 intravenously with 0.1 mL of a 0.5% suspension of SRBC or intramuscularly with 0.1 mL of a 25% suspension of SRBC. Antibody response was measured 6 and 14 d later. Chicks received a booster i.m. inoculation of 0.1 mL of 25% SRBC on d 28. Titers were again measured 6 and 14 d later. Level of vitamin E fed to dams did not affect progeny BW or plasma vitamin E levels. Although titers were higher following i.v. than i.m. inoculation, the degree of difference varied among stocks. Dietary vitamin E level interacted with inoculation route with a greater response to the higher than lower level of vitamin E for i.v., but there was no difference for i.m. There were stock × level of vitamin E and stock × route of inoculation interactions for secondary responses to SRBC inoculation. Stock rankings after the first inoculation were not predictive of the rankings after the second inoculation. The 30-fold increase in dietary level of vitamin E resulted in >12-fold differences in plasma levels of vitamin E. Overall, there was a stock-dependent influence of dietary vitamin E on growth and humoral antibody response.

Strategies to alleviate the incidence of ascites in broilers: a review

Ascites is a complex problem caused by many interacting factors such as genetics, environment and management. Many nutritional, medicinal and management strategies have been proposed to alleviate the problem. Higher levels of dietary vitamin C and E along with selenium yeast might be beneficial, presumably because of their role in improving cellular integrity. Oils rich in n-3 fatty acids have been shown to reduce pulmonary hypertension and, consequently, ascites incidence. The potential use of flax oil has already been demonstrated, whereas the effects of other oils rich in n-3 fatty acids (fish, linseed and canola oils) remain to be investigated. The assessment of the effects of dietary electrolyte balance on ascites incidence seems to be a promising field of research in broiler nutrition. In general, reducing the dietary level of salt (NaCl) and adding bicarbonates to the diet and drinking water have been proposed as potential "cost-effective" methods to reduce ascites incidence. The use of nutrients/drug agents that increase the vascular capacity of the lungs or decrease the pulmonary vascular resistance may help to alleviate the problem, but economic and local feed regulations might restrict such use. Diuretics have also shown positive effects, presumably because there is a reduction of sodium and fluid retention in the body; litter humidity however must be closely monitored if diuretics are continuously administered. As the high metabolic rate (fast growth) is a major factor contributing to the susceptibility of broilers to ascites, early-age feed or nutrient restriction (qualitative or quantitative) or light restriction in order to slow down the growth rate seem practically viable methods, since final body weight is not compromised. Optimization of the house temperature and ventilation in cold weather seem helpful practices to decrease ascites incidence. Under practical conditions, it might be interesting to test the additive effects of different approaches when used in combination.

JAMAICAN LIZARDS' BALANCING ACT

In vertebrates, vitamin D plays an important role in maintaining the body's calcium levels through the calcium-phosphorous hormonal regulation system. Animals with low vitamin D levels suffer from calcium deficiency, which leads to numerous maladies. Thus, animals need to maintain their vitamin D stores to stay healthy, and do so either by absorbing vitamin D from their food or by producing it themselves. However, producing your own supply of vitamin D requires ultraviolet-B (UV-B) radiation, and since animals clearly differ in the time they spend sunbathing, the relative importance of these two vitamin D sources varies considerably among animals. Generally, creatures that eat food with low vitamin D levels appear to rely mostly on UV-B-generated vitamin D,while nocturnal and other animals that rarely see sunlight appear to be unable to generate their own and presumably depend on rich dietary vitamin D sources instead.Ferguson and colleagues at Texas Christian University wondered if this general pattern of attaining vitamin D applies to closely related species that live in the same place, but experience different UV-B and dietary vitamin D availabilities. To find out, they compared the natural UV-B exposure, the skin's ability to photobiosynthesize (generate its own) vitamin D, and dietary vitamin D levels of two Jamaican lizards: Anolis lineotopus merope, a shade-dweller, and Anolis sagrei, which prefers to bask in the sun.To quantify natural UV-B exposure, Ferguson and colleagues watched adult lizards of the two species for nine continuous hours, recording each lizard's location and sun-exposure (whether they were sitting in full-sun, filtered-sun or shade) every five minutes. To assess the amount of UV-B irradiation the lizards experienced in these locations, on a subsequent day they re-enacted each lizard's movements on the observation day using artificial `lizard models'. The models were ampules that contained provitamin D, which is converted to vitamin D in proportion to UV-B exposure. To measure how effective the lizards were at generating their own vitamin D, the team assessed skin sensitivity for vitamin D biosynthesis by exposing skin samples from each species to 0, 20, 40 or 60 minutes of UV-B irradiation and measuring vitamin D production. Finally, they assessed the lizards' natural levels of dietary vitamin D by determining vitamin D levels in the stomach contents of wild-caught lizards.The team found that the shade-dweller A. lineotopus meropeexperienced less UV-B irradiation than the sun-loving A. sagrei but,unexpectedly, they didn't compensate for this by eating vitamin D-rich food;in fact, the sun-lovers had more vitamin D in their food. So how do the shade-dwellers cope? Ferguson et al. provide an explanation: the shade-dweller's skin is much more sensitive to UV-B-induced vitamin D biosynthesis than that of A. sagrei; they are simply better at producing vitamin D, despite the lack of sun. Ferguson et al. argue that the reduced skin sensitivity of A. sagrei to vitamin D biosynthesis may reflect a lesser need for self-generated vitamin D, since there is enough of it in their diet, and a greater need for UV-B sunscreen to protect their skin from the damaging influence of UV-B. Thus, it appears that these lizards can adjust their skin's UV-B sensitivity, so they can strike a balance between avoiding UV-B damage and generating their own vitamin D.