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Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiv,148 pages; also includes graphics Includes bibliographical references (p. 121-136). Available online via OhioLINK's ETD Center

Various aspects of the ascorbic acid (vitamin C) nutrition of Oreochromis niloticus and O. mossambicus are considered in this treatise. The activity of L-gulono-Y-lactone oxidase was assessed in liver and kidney of 14 teleosts of 3 genera, histochemically (qualitatively) and biochemically (quantitatively). Activity of this enzyme was only detected in liver and kidney of common carp, Cyprinus carpio, and kidney of O. spilurus and O. aureus. No activity was detected in the species considered herein. The quantitative dietary ascorbic acid requirements of juvenile O. niloticus and O. mossambicus were determined by feeding diets containing graded levels of the vitamin (O~400mg/lOOg) and were based on growth response, food utilization, gross body composition data, tissue and biochemical changes and ability to prevent signs of ascorbic acid deficiency. The recommended level of supplementation of dietary ascorbic acid is l2Smg/lOOg and the net requirement 42mg/lOOg diet. Long-term ascorbic acid deprivation in £. niloticus and O. mossambicus resulted in poor performance in terms of growth, food utilization and survival. Other parameters evaluated included hepatosomatic index, liver and muscle glycogen content, blood parameters, tissue ascorbate concentrations, collagen contents, hydroxyproline and proline contents, and serum transaminase and cholesterol levels. Signs of ascorbic acid deficiency were severe and included haemorrhage~ opercular deformity, tail erosion, exophthalmia, cataract and spinal deformity (lordosis and scoliosis). Histologically scorbutic fish showed evidence of generalized bone changes associated with excessive production of chondrocytes and failur~ of ossification of growing bone areas. Eye lesions were associated with scleral collapse and also observed was hyperplasia of gill secondary lamellae epithelial cells and pronounced steatitis. Tissue ascorbate concentrations were correlated with dietary ascorbic acid levels and both species exhibited highest concentrations in the ovary, brain and testis, followed by heart, liver, gut, gills, eyes and the lowest levels in muscle and gall-bladder. The physiological role for ascorbic acid in each tissue is discussed. Eight week growth studies were conducted to evaluate the utilization of L-ascorbic acid (AA), the sodium salt of L-ascorbic acid (NaAA), glyceride coated L-ascorbic acid (GCAA), the barium salt of L-ascorbic acid 2-sulphate (AA2S) and ascorbyl palmitate CAP) in diets for O. niloticus and O. mossambicus, All five forms were added to the basal diet, containing no ascorbic acid CAAF), on an equimolar basis to supply 12Smg ascorbic acid/IOOg diet. All forms performed well in terms of growth, food utilization, and prevented signs of deficiency, Retention of ascorbic acid in diets after processing was increased by increasing dietary ascorbic acid level. AA2S and GCAA were more stable than AA and NaAA during processing and storage. The stability of AA, NaAA, GCAA and AA2S under different storage conditions was in descending order as follows: Freezer (_20°C), Fridge (S-BoC), room temperature in black bags (22-24°C) and room temperature in clear bags (22-24°C). Leaching of dietary ascorbic acid increased with increasing immersion time and water temperature. Stability and price of each form evaluated suggested that GCAA is to be preferred for use in fish feeds. The antioxidant effects of ascorbic acid were investigated. The results showed that ascorbic acid was not as effective as butylated hydroxy toluene (BHT) in preventing in vitro oxidation. An experiment was conducted to compare the performance of a commercial trout diet with the same diet supplemented to a level of l2Smg ascorbic acid/lOOg diet (Diet 2) when fed to O. niloticus. Fish fed the supplemented diet performed significantly better in terms of growth and food utilization concomittant with significantly increased tissue ascorbate concentrations. Sex differences in relation to dietary ascorbic acid nutrition were investigated. Females of both species exhibited significantly higher gonado~ and hepatosomatic indices than males. Females in both species eXhibited higher total ascorbate concentrations in gonad, gills, spleen, brain and blood than males whereas the reverse was true for the eyes. Dehydroascorbic acid (DHAA) levels were very low in tissues of both species. Ascorbic acid depleted O. niloticus fingerlings were fed on each of three diets providing nil, adequate Cl2Smg ascorbic acid/lOOg diet), and luxus (400mg/lOOg diet) of the vitamin after small surgical incisions had been made in dorsolateral musclature. Fish from each group were sampled regularly over 16 days and histological evaluation of the lesion area carried out as well as measurement of the tissue ascorbate levels. Epithelial elements of the healing process developed irrespective of the vitamin level but although fibroblast activity was marked in all three groups, collagenisation was very much slower in the deficient group, and in these the lesion was not mature, even at the termination of the experiment. The role of ascorbic acid in reproduction of tilapias was investigated in three experiments. The first showed that ascorbic acid supplementation of broodstock feed improved both hatchability and fry condition. In the second experiment fry produced from fish fed an unsupplemented diet and subsequently fed the same diet performed poorly in respect of growth and food utilization. Fry produced from broodstock fed the supplemented diet and subsequently fed the unsupplemented diet performed better than the previous group. This indicates transfer of ascorbic acid from the ovary to the eggs thence to the fry providing some protection against ascorbic acid deficiency during the early stages of life.

The purpose of this investigation was to study the influence of the ration of the cow upon the vitamin C content of milk. The determinations were made by the biological assay method and by the chemical titration method. The cows were given four kinds of rations. Similar determinations have been made by other workers. A brief resume of their technique and conclusions follows: From the results of this investigation, it is concluded: 1. That the ascorbic acid content of milk decreases as the stage of lactation increases. 2. That the ascorbic acid of the milk of individual cows varies within the breed. 3. That the age of the cow does not influence the vitamin C content of the milk. 4. That the rate of gain of the assay animals over a period of 74 days was independent of the ascorbic acid content. 5. That the vitamin C content seems to be independent of the ration of the cow. 6. That the “spring milk” carried some factor which influenced a greater gain of weight than other “winter” milk rations. / Master of Science

Two identical experiments were conducted to evaluate the combined effects of arginine (AR), vitamin E (VE) and vitamin C (VC) on cardiopulmonary performance and ascites parameters of broilers reared under cold environmental temperature. One d old male broilers were fed a basal corn-soybean meal diet (CTL, 1.2 % AR and 40 IU VE), the basal diet supplemented with 1% AR and either 200 IU VE (AE group), or 500 mg of VC (AC group), or a combination of VE and VC (AEC group) at the same level per kg of feed. Pulmonary arterial pressure (PAP) and mean arterial pressure (MAP) were recorded in clinically healthy anesthetized birds (28-42 d old) before and after an epinephrine challenge (EPI, 0.5 mg/kg BW i.v.), Amino-guanidine Hemisulphate (AG, 100 mg/kg BW i.v.) and N-Nitro L-Arginine Methyl Ester (L-NAME 50 mg/kg BW, i.v.) at 20 min intervals. The PAP increased 30 s after EPI in all birds, but the peak PAP was lower in the AEC group than in all the other birds. After 120 s of challenge the PAP was lower in AEC birds compared to the other birds. The PAP returned to pre-EPI levels within 300 s in all groups. The PAP was increased ( P< 0.05) within 60 s after the AG and L-NAME challenge in all groups, but no differences were found among groups. Plasma nitric oxide (NO) was higher in the AEC birds than in all the other groups before and after challenge. Our results showed that birds fed AEC maintained a lower PAP than the CTL birds after EPI elicited an increase in cardiac output and this can be explained by a higher production of NO. A combination of AR, VE, and VC may have complementary effects against oxidative stress, protecting the endothelium and preserving NO function.

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