Dietary Ascorbic Acid Levels Research Articles

Ascorbic acid biosynthesis in Pacific abalone Haliotis discus hannai Ino and L-gulonolactone oxidase gene loss as an independent event

Up to now, it has been believed that invertebrates are unable to synthesize ascorbic acid (AA) in vivo. However, in the present study, the full-length CDs (Coding sequence) of L-gulonolactone oxidase (GLO) from Pacific abalone (Haliotis discus hannai Ino) were obtained through molecular cloning. The Pacific abalone GLO contained a FAD-binding domain in the N-termination, and ALO domain and conserved HWAK motif in the C-termination. The GLO gene possesses 12 exons and 11 introns. The Pacific abalone GLO was expressed in various tissues, including the kidney, digestive gland, gill, intestine, muscle and mantle. The GLO activity assay revealed that GLO activity was only detected in the kidney of Pacific abalone. After a 100-day feeding trial, dietary AA levels did not significantly affect the survival, weight gain, daily increment in shell length, and feed conversion ratio of Pacific abalone. The expression of GLO in the kidney was downregulated by dietary AA. These results implied that the ability to synthesize AA in abalone had not been lost. From the evolutionary perspective, the loss of GLO occurred independently as an independent event by matching with the genomes of various species. The positive selection analysis revealed that the GLO gene underwent purifying selective pressure during its evolution. In conclusion, the present study provided direct evidence to prove that the GLO activity and the ability to synthesize AA exist in abalone. The AA synthesis ability in vertebrates might have originated from invertebrates dating back 930.31 million years.

EFFECT OF SUPPLEMENTAL ASCORBIC ACID AND DISTURBANCE STRESS ON THE PERFORMANCE OF BROILER CHICKENS

The study was conducted with four hundred day-old Anak broilers to determine the effects of dietary Ascorbic acid (AA) and disturbance (D) stress on the performance of broiler chickens in a tropical environment. There were four treatments consisting of two levels of disturbance (ID) and (4D) and two levels of dietary AA (0 and 250mgAA/kg feed). Each treatment was replicated four times with 25 chicks per replicate. The starter and finisher diets were formulated to be isonitrogenous and isocaloric. Results showed that there were no significant interactions between dietary ascorbic acid supplementation and disturbance stress levels on any of the performance data considered. The disturbance stress had no significant effects on most of the measured parameters. However, there was # 35% increase in mortality rate as disturbance stress level increased from D to 4D. The dietary ascorbic acid supplementation level had no significant effect on feed intake and weight gain. Feed conversion ratios were significantly improved with AA supplementation during the starter phase only. Dietary AA supplementation also had a 90% reduction in mortality of chicks compared with the supplemented group. Likewise AA inclusion in diets had a feed cost advantage. It may be concluded that disturbance induced stress increased mortality and lowered performance. However these effects were relieved by dietary AA supplementation.

Dietary ascorbic acid requirement for the optimum growth performances and normal skeletal development in juvenile hybrid grouper, Epinephelus fuscoguttatus × Epinephelus lanceolatus

A 10-week feeding trial was conducted to determine the dietary ascorbic acid required by the juvenile hybrid grouper, Epinephelus fuscoguttatus × Epinephelus lanceolatus for its optimum growth, survival, and normal skeletal development. Eight experimental diets containing graded levels of ascorbic acid (4.8, 11.2, 24.1, 47.2, 75.6, 95.4, 156.2, and 303.0 mg/kg) were prepared and labeled as C5, C11, C24, C47, C76, C95, C156 and C303, respectively. Each diet was fed to triplicate groups of fish [initial weight 7.71 ± 0.06 g (mean ± SD)]. The fish were cultured in 150 L of fiber glass tank supplied with aeration and flow-through seawater system (3 L min−1) with the stocking density of 15 individual per tank. During the feeding trial, fish were hand-fed with the experimental diets to apparent satiation twice a day (8:00 and 15:00). Bulk weight of each fish group was measured at 2 weeks interval. At the end of the experiment, fish were sacrificed and subjected to radiographic imaging to detect the presence of skeletal deformities. The body weight gain (BWG) of fish was in the range from 628.51 ± 39.61 to 880.18 ± 113.30%. Fish fed with the C156 diet gained the highest BWG and specific growth rate (SGR). In the present study, ascorbic acid level did not affect the survival of the hybrid grouper. The feed conversion ratio (FCR) value in all dietary treatments appeared to be less than 1, indicating hybrid grouper have high efficiency of converting feed into body mass. Multiple types of skeletal deformities (fusion, kyphosis, lordosis, and scoliosis) were observed in the fish fed with the diets containing less than 95 mg/kg of ascorbic acid. In conclusion, dietary ascorbic acid levels can affect the growth performance and normal skeletal development in the hybrid grouper. Although 95 mg/kg was sufficient for normal skeletal development, 156 mg/kg of dietary ascorbic acid is recommended for feed development to maintain the optimum growth and normal skeletal development in the fish.

Dietary ascorbic acid influences the intestinal morphology and hematology of hybrid sorubim catfish (Pseudoplatystoma reticulatum × P. corruscans)

This study evaluated the effect of graded levels of dietary ascorbic acid (AA) (12.47, 20.27, 115.44, 475.50, 737.72, and 850.70 mg kg−1) on growth, hematology, intestinal morphometry, and phagocyte activity of hybrid sorubim Pseudoplatystoma reticulatum × Pseudoplatystoma corruscans. Fish (n = 420, 14.57 ± 2.71 g, 15.11 ± 0.90 cm) were distributed in 30 polyethylene tanks (80 l) (5 replicates per treatment with 14 fish per tank) and fed for 45 days. Dietary treatment did not have a significant effect on growth metrics (P > 0.05). Fish fed 737.72 mg AA kg−1 had a higher villi height (289.80 ± 19.96 μm) (P 0.05) of dietary AA on leukocyte and thrombocyte and on phagocyte activity and phagocyte index. Inclusion of AA in feed seems to increase the integrity of the intestinal mucosa and stimulate erythropoiesis in hybrid sorubim catfish.

Dietary ascorbic acid requirement for growth of striped catfish,Pangasianodon hypophthalmus(Sauvage, 1878) juveniles

A sixty-day feeding trial was conducted to determine the ascorbic acid (AA) requirement for growth of striped catfish, Pangasianodon hypophthalmus juveniles. Seven iso-nitrogenous and iso-energetic (370 g protein per kg and 19.6 MJ/kg) purified diets were prepared with different levels of ascorbic acid such as control (0), T1 (17.5), T2 (35), T3 (70), T4 (175), T5 (350) and T6 (700) mg ascorbic acid (L-ascorbyl-2-polyphosphate) equivalent per kg diet. Fish with a mean body weight of 3.2–3.4 g were stocked (fifteen fish per tank) in triplicates following a completely randomized design. Each group was fed to satiation twice a day for 60 days. Significant differences were observed in growth, survival, body composition and metabolic enzymes activities with different dietary ascorbic acid levels. Maximum weight gain, specific growth rate (SGR) and protein efficiency ratio (PER) were found in fishes fed with 35 mg AA per kg diet, supported by best feed conversion. Fish fed a diet containing vitamin C had the highest activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) compared to those fed with vitamin C-depleted diets. In this study, based on using broken-line regression analysis, the dietary vitamin C requirement for growth of P. hypophthalmus juveniles was estimated to be in the range of 46–76 mg AA per kg, depending on the criterion used, growth and liver storage. Our results will be helpful for the formulation of cost-effective ascorbic acid incorporated diets for striped catfish, P. hypophthalmus.

Effect ofl-ascorbyl-2-polyphosphate supplementation on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp,Litopenaeus vannamei

An 8-week feeding trial was conducted to evaluate the effects of ascorbic acid (AsA), in the form of l-ascorbyl-2-polyphosphate (LAPP) on growth performance, body composition, antioxidative capacity and salinity stress tolerance of juvenile Pacific white shrimp, Litopenaeus vannamei. Five practical diets (46% crude protein and 7.6% lipid) supplemented with graded levels of AsA (14.64, 48.55, 84.98, 308.36 and 639.27 mg kg−1 diet) were fed to five replicate groups of L. vannamei (mean initial wet weight 0.57 g). No significant differences were found on growth performance among all treatments. However, whole body lipid content significantly decreased with dietary AsA levels increasing. Activities of total antioxidant capacity, glutathione reductase and glutathione peroxidase were significantly affected by dietary AsA levels. Shrimp fed LAPP-free diet had higher malondialdehyde content than those fed the diets supplemented with LAPP. Dietary AsA levels higher than 308.36 mg kg−1 diet increased the survival of shrimps after 1, 2 and 3 h of acute salinity change. Broken-line regression analysis on survival after 3 h of salinity stress and second-degree polynomial regression analysis on glutathione reductase data indicated that the optimal dietary AsA requirement of L. vannamei was estimated to be 306.39, 319.75 mg kg−1 diet respectively.

Effects of dietary ascorbic acid levels on the growth, energy budget, and immunological performance of green, white, and purple color morphs of the sea cucumber, Apostichopus japonicus

Ascorbic acid plays an important role in the growth and immunity of the sea cucumber, Apostichopus japonicus, a valuable commercial species in China, South Korea, and Japan. In this study, we investigated the dietary ascorbic acid requirements of two newly discovered color morphs of A. japonicus, white and purple, and compared them with that of the common green morph. Six test diets were formulated containing 0, 50, 100, 200, 400, and 800mg ascorbic acid equivalent per kg, as l-ascorbyl-2-polyphosphate. The color morphs were fed the test diets for 60days, and their growth, energy budget, and immunological performance recorded. Dietary ascorbic acid levels had a significant effect on the growth of A. japonicus (P<0.001). The green and purple morphs showed the greatest specific growth rate (SGR), ingestion rate (IR), and food conversion efficiency (FCE) at a dietary ascorbic acid level of 200mg/kg, while maximum values for the white morph were recorded at 100mg/kg, indicating a lower ascorbic acid requirement in the white morph than the green and purple morphs. This could be due to the lower growth and metabolic rates recorded in the white morph, whose SGR, IR, and FCE values and immune indicators were lower than the green and the purple morphs. Malonaldehyde (MDA) content of the coelomic fluid was significantly lower when dietary ascorbic acid was≥200mg/kg (P<0.05). Superoxide dismutase (SOD) and catalase (CAT) activities, and total anti-oxidative capacity (T-AOC) were generally higher at dietary ascorbic acid levels of 100, 200, and 400mg/kg compared with the other treatments. SOD and CAT activities and T-AOC were significantly and positively correlated with SGR, indicating that supplementary dietary ascorbic acid had a beneficial effect on growth and immunity. SGR, energy intake, and the proportion of energy allocated to growth decreased significantly in the white and purple morphs when ascorbic acid levels reached 800mg/kg (P<0.05); as did those of the green morph, but not to a significant level. Immune indicators decreased and MDA content increased slightly at 800mg/kg, indicating that high levels of dietary ascorbic acid do not benefit growth or immunity. The SOD and CAT activities were higher in the purple morph than the green and white morphs, indicating its superior immune system capacity. Optimum growth and immunity of A. japonicus were achieved at ∼100mg/kg of ascorbic acid in the white morph and 200mg/kg in the green and purple morphs.

Effectiveness ofl-ascorbyl-2-polyphosphate as an ascorbic acid source for sea cucumber,Apostichopus japonicus

A feeding trial was conducted to determine the adequate dietary ascorbic acid (AsA) levels and the effects on growth, meat quality and antioxidant status of sea cucumber (10.04 ± 0.06 g), Apostichopus japonicus. l-ascorbyl-2-polyphosphate (35% AsA equivalent) was supplemented separately to the basal diet to obtain five AsA levels, 0, 598, 1473, 4676 and 14340 mg kg−1 diet respectively. After 60-day feeding trial, the sea cucumbers fed diets containing 598 and 1473 mg AsA kg−1 showed significantly higher (P < 0.05) body weight gain and specific growth rate values than the sea cucumbers fed control diets. The sea cucumbers fed diets containing 1473 and 4676 mg AsA kg−1 showed significantly higher (P < 0.05) hydroxyproline contents than those of the sea cucumbers fed diets containing 0 and 598 mg AsA kg−1. Antioxidant enzymes such as total antioxidant capacity, superoxide dismutase and glutathione peroxidase showed increasing trends with the increasing dietary AsA levels, but no significant differences (P > 0.05) were observed when the sea cucumbers fed diets with high dietary AsA levels. The content of malondialdehyde had the opposite trend of antioxidant enzymes. In conclusion, the adequate dietary AsA level focusing on growth performance of sea cucumber is between 598 and 1473 mg kg−1 diet. Furthermore, high level of dietary AsA (between 598 and 4676 mg kg−1 diet) improved meat quality and antioxidant status.

Dietary ascorbic acid modulates the expression profile of stress protein genes in hepatopancreas of adult Pacific abalone Haliotis discus hannai Ino

This study was conducted to investigate the effects of dietary ascorbic acid (AA) on transcriptional expression patterns of antioxidant proteins, heat shock proteins (HSP) and nuclear factor kappa B (NF-κB) in the hepatopancreas of Pacific abalone Haliotis discus hannai Ino (initial average length: 84.36 ± 0.24 mm) using real-time quantitative PCR assays. L-ascorbyl-2-molyphosphate (LAMP) was added to the basal diet to formulate four experimental diets containing 0.0, 70.3, 829.8 and 4967.5 mg AA equivalent kg−1 diets, respectively. Each diet was fed to triplicate groups of adult abalone in acrylic tanks (200 L) in a flow-through seawater system. Each tank was stocked with 15 abalone. Animals were fed once daily (17:00) to apparent satiation for 24 weeks. The results showed that the dietary AA (70.3 mg kg−1) could significantly up-regulate the expression levels of Cu/Zn superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), feritin (FT) and heat shock protein 26 (HSP26) in the hepatopancreas of abalone in this treatment compared to the controls. However, the expression levels of Mn-SOD, glutathione peroxidase (GPX), thioredoxin peroxidase (TPx), selenium-binding protein (SEBP), HSP70 and HSP90 were significantly down-regulated. Compared with those in the group with 70.3 mg kg−1 dietary AA, the expression levels of CAT, GST and HSP26 were decreased in abalone fed with very high dietary AA (4967.5 mg kg−1). In addition, significant up-regulations of expression levels of Mn-SOD, GPX, TPx, SEBP, FT, HSP70, HSP90 and NF-κB were observed in abalone fed with apparently excessive dietary AA (829.8 and 4967.5 mg kg−1) as compared to those fed 70.3 mg kg−1 dietary AA. These findings showed that dietary AA influenced the expression levels of antioxidant proteins, heat shock proteins and NF-κB in the hepatopancreas of abalone at transcriptional level. Levels of dietary AA that appeared adequate (70.3 mg kg−1) reduced the oxidative stress by influencing gene expression of antioxidant proteins, but excessive dietary AA (829.8 and 4967.5 mg kg−1) induced oxidative stress in Pacific abalone H. discus hannai.

Effect of dietary vitamin C on the growth performance and innate immunity of juvenile cobia (Rachycentron canadum)

This study was conducted to evaluate the effects of dietary vitamin C on growth performance, hematologic parameters and innate immune responses in juvenile cobia, Rachycentron canadum. Seven practical diets were formulated to contain 0.0 (as the basal diet), 13.6, 27.2, 54.4, 96.6, 193.4 and 386.5 mg ascorbic acid equivalent kg−1 diet. Each diet was fed to triplicate groups of juvenile cobia with initial body weight of 5.5 g in 500-L cylindrical fiberglass tank. The results of 8 weeks feeding trial showed that typical vitamin C-deficient signs such as spinal deformation and body nigrescence were observed in the fish fed the basal diet. Fish fed the basal diet had significantly lower weight gain, specific growth rate (SGR), protein efficiency ratio (PER) and feed efficiency (FE) than those fed the diets supplemented with vitamin C, but no significant differences were observed among diets supplemented with vitamin C. However, survival rate was significantly affected by the dietary vitamin C levels, fish fed the basal diet had lower survival rate than those fed the diets supplemented with vitamin C. The ascorbic acid concentration in liver was correlated positively with the dietary vitamin C levels, however, the thiobarbituric acid reactive substances (TBARS) concentrations in liver was not significantly affected by the dietary vitamin C levels, although, fish fed the basal diet had the highest TBARS values among all treatments. The activities of serum lysozyme, superoxide dismutase (SOD), alkaline phophatase (AKP) and total immunoglobulin (Ig) were significantly influenced by the dietary vitamin C levels, fish fed the basal diet had lower lysozyme, SOD, AKP and total Ig than those fed diets supplemented with vitamin C. The serum glucose and triglyceride concentrations were significantly affected by the dietary vitamin C levels. Fish fed the basal diet had lower red blood cell and hemoglobin values than those fed the vitamin C supplemented diets. The challenge experiment with Vibrio harveyi showed that lower cumulative survival was in fish fed the unsupplemented diet, the cumulative survival were significantly increased with increase of the dietary ascorbic acid levels from 13.6 to 96.6 mg kg−1, while the cumulative survival reached plateau when dietary ascorbic acid levels increased from 96.6 to 386.5 mg kg−1. These results indicated that dietary vitamin C did significantly influence on growth performance and immune response of juvenile cobia.

Adverse and beneficial effects of long-term high-concentration ascorbic acid supplementation in rainbow trout Oncorhynchus mykiss

The present study examined the effects of high-concentration ascorbic acid (AsA) supplementation over a long period on growth, plasma components, nonspecific immune responses, and thermal tolerance in rainbow trout Oncorhynchus mykiss. Four commercial diets supplemented with 0, 100, 1000, and 5000 mg AsA per kg of diet (designated AsA0, AsA100, AsA1000, and AsA5000, respectively) were fed to rainbow trout (initial weight 1.85 g) for 100 days. AsA contents in liver increased with increasing dietary AsA levels. Feeding period, growth performance, and plasma components did not differ significantly between the AsA groups. On the other hand, the phagocytic assay [nitro-blue tetrazolium (NBT) assay] was significantly higher in fish fed AsA1000 and AsA5000 than those fed a diet without AsA (AsA0) at the end of feeding trial. Superoxide dismutase (SOD) activity in the intestines of fish fed AsA5000 was also significantly higher than that of fish fed AsA0. In the thermal tolerance test, fish fed AsA5000 only showed significantly lower cumulative mortality compared with the AsA0 group. In conclusion, high-concentration AsA supplementation such as AsA5000 over a long period does not induce any adverse effects and can enhance disease and stress resistance in rainbow trout.

Imbalanced dietary ascorbic acid alters molecular pathways involved in skeletogenesis of developing European sea bass ( Dicentrarchus labrax)

The influence of dietary ascorbic acid (AA) on growth and morphogenesis during the larval development of European sea bass ( Dicentrarchus labrax) was evaluated until 45 days post hatching. Diets incorporated 0, 5, 15, 30, 50 or 400 mg AA per kg diet to give AA-0, AA-5, AA-15, AA-30, AA-50 and AA-400 dietary treatments, respectively. Dietary AA levels lower than 15 mg/kg reduced larval growth and survival was affected in specimens fed diets devoid of AA. Globally, disruption of the expression of genes involved in AA and calcium absorption in the intestine (SVCT-1, TRPV-6), skeletogenesis (BMP-4, IGF-1, RARγ) and bone mineralization (VDRβ, osteocalcin) were observed in groups fed doses lower and higher than 50 mg AA/kg diet. Such disturbances detected at molecular level were associated with disruptions of the ossification process and the appearance of skeletal abnormalities.

Effects of graded levels of dietary vitamin C on the growth, digestive capacity and intestinal microflora of juvenile Jian carp (Cyprinus carpio var. Jian)

A 60-day experiment was carried out to study the effects of vitamin C [ascorbic acid (AA)] on the growth, digestive enzyme activities and intestinal microbial population. Diets with six levels (0.0, 21.4, 45.1, 69.5, 93.6 and 142.1 mg AA kg−1 diet) of supplemental ascorbyl polyphosphate were fed to juvenile Jian carp (Cyprinus carpio var. Jian) (12.63±0.02 g). The specific growth rate (SGR), feed efficiency and productive protein value were significantly improved with increasing AA levels up to 45.1 mg AA kg−1 diet (P<0.05). The hepatopancreas and muscle AA concentrations were increased with increasing dietary AA levels up to 69.5 and 45.1 mg kg−1 diet respectively (P<0.05). The activities of intestinal trypsin, chymotrypsin, lipase, α-amylase, Na+, K+-ATPase, alkaline phosphatase, gamma-glutamyl transpeptidase and creatinkinase were all positively affected by the AA supplementation (P<0.05). Intestinal Lactobacillus and Bacillus were increased with increasing AA levels up to 45.1 mg AA kg−1 diet (P<0.05), while intestinal Escherichia coli decreased with increasing AA levels up to 45.1 mg AA kg−1 diet (P<0.05). In conclusion, AA improve the digestive capacity and intestinal microbial population of Jian carp, and the dietary AA requirement for SGR of juvenile Jian carp was 40.9 mg AA kg−1 diet.

Interactive effects of dietary vitamin C and phospholipid in micro-bound diet for growth, survival, and stress resistance of larval red sea bream, Pagrus major

This study was conducted to examine the effects of dietary ascorbic acid (AsA) and phospholipid (PL) and their interaction on growth, survival, and stress resistance in red sea bream larvae. Twenty-six days old red sea bream were fed nine micro-bound diets supplemented three levels of AsA (0, 800 and 1600 mg kg−1 diet) and PL (0, 20 and 40 g kg−1 diet) for 15 days. Dietary AsA and PL were both significant factors on survival rates. There was also an interaction between dietary AsA and PL on survival rate (P < 0.05). The larvae fed 800 or 1600 mg kg−1 AsA with 40 g kg−1 PL diets showed the highest survival rate, with values similar to those of the live-food supplemented group. Stress resistance against low salinity exposure significantly increased with increased dietary level of AsA and PL. However, significant interaction of AsA and PL was not detected. The larvae fed 1600 mg kg−1 AsA with 40 g kg−1 PL diet showed the highest stress resistance among all diets, but it was not significantly different than that of larvae fed 800 mg kg−1 AsA with 40 g kg−1 PL diet. This study clearly demonstrated that combined use of AsA and PL can improve survival of 26–40 days posthatching red sea bream larvae. Moreover, the present study suggested that 800 mg kg−1 AsA with 40 g kg−1 PL in diet was needed for producing high quality seedling under the stressful conditions.

Ascorbic acid influences the development and immunocompetence of larval Heliothis virescens

AbstractAscorbic acid, known to be a free radical scavenger and vital to insect development, is important in larval resistance to baculovirus infection. We sequentially elevated the ascorbic acid content in an ascorbic acid‐depleted diet and evaluated the effect on larval Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) development and immunocompetence. Dietary ascorbic acid levels lower than 0.7 g l−1 slowed the growth rate of larvae, reduced pupal weights significantly, and severely inhibited adult emergence. Larvae developing on ascorbic acid‐free diet experienced far higher levels of mortality following per os infection with virus. Additionally, viral infection in larvae fed an ascorbic acid‐free diet, as monitored by epifluorescence microscopy, showed signs of infection much earlier than larvae fed control levels of ascorbic acid. These results demonstrate an indirect correlation between the level of ascorbic acid in the food stream of larval H. virescens and the susceptibility of the insect to baculoviral infection.

Effects of Dietary Ascorbic Acid on Blood Haematological Profile, Serum Biochemical Components and Tonic Immobility Reaction of Male Turkeys under Summer Condition

This experiment was performed to determine the effects of dietary ascorbic acid (ASA) supplementation on blood components, leukocyte and tonic immobility of male turkeys under summer conditions. A total of 120 one-day-old male turkeys were fed with three different diets. The experimental diets were: control without ASA (ASA-0), 150mg of ASA/kg (ASA-150) and 300mg of ASA/kg (ASA-300) of diet. The turkeys received the experimental diets for 18 weeks. Diets in mash form and water were provided ad libitum. In the ASA-150 and ASA-300 groups, the eosinophile and basophile ratios were higher than those of the ASA-0 group at 12 weeks of age (P 0.05). Both dietary ASA levels caused a quadratic decrease in serum cholesterol, low density lipoprotein (LDL) and glutamic-oxaloacetic transaminase (SGOT) (P 0.05). As a conclusion, blood haematological profile, serum biochemical components and tonic immobility of turkeys were not significantly affected by dietary ASA levels at chronic high summer temperatures in general, and, therefore, there is no need for ASA supplementation in turkeys' diets under summer temperatures that do not exceed 31.7°C.

Preliminary Study of the Optimum Dietary Ascorbic Acid Level in Sea Cucumber, Apostichopus japonicus (Selenka)

Abstract A 14‐wk feeding trial was carried out to evaluate the optimum dietary ascorbic acid (AA) level in juvenile sea cucumber, Apostichopus japonicus. Sea cucumbers averaging 1.49 ± 0.07 g (mean ± SD) were randomly distributed into 18 rectangular plastic tanks of 20 L capacity in a recirculating system (20 animals per tank). Six semipurified experimental diets were formulated to contain 0 (l‐ascorbyl‐2‐monophosphate [AMP]; AMP0), 30 (AMP24), 60 (AMP48), 120 (AMP100), 240 (AMP206), and 1200 (AMP1045) mg AA/kg diet in the form of AMP using casein as the main protein source. Sea cucumbers were fed each of the six experimental diets in triplicate groups. At the end of 14 wk of feeding trial, weight gain (WG), specific growth rate (SGR), and feed efficiency (FE) of sea cucumbers fed AMP100, AMP206, and AMP1045 were significantly (P &lt; 0.05) higher than those of animals fed AMP0, AMP24, and AMP48. However, there were no significant differences in WG, SGR, and FE among sea cucumbers fed AMP100, AMP206, and AMP1045 and among animals fed AMP0, AMP24, and AMP48. Whole‐body vitamin C concentration increased with AA content of the diets. Broken‐line analysis of WG showed an optimum dietary AA level of 105.3 mg AA/kg diet in sea cucumber. These results indicated that the optimum dietary vitamin C level in sea cucumber in the form of AMP could be greater than 100 mg AA/kg diet but less than 105.3 mg AA/kg diet.

Developmental response of Euplectrus comstockii to ascorbic acid in the diet of the larval host, Heliothis virescens

Recent developments in genetic engineering have paved the way for researchers to produce crops of high nutritional and yield value, in addition to being resistant to diseases and pests. Ascorbic acid content is one of the parameters researchers are trying to enhance in plants. This study investigated the effect of different levels of dietary ascorbic acid of a beneficial wasp, Euplectrus comstockii Howard (Hymenoptera: Eulophidae), by measuring life history parameters of the wasp when reared on lepidopteran larvae fed a basal diet containing low and high levels of ascorbic acid. Odds and odds ratio analyses showed that the probability of egg hatch and adult emergence for the wasp increased with the amount of ascorbic acid in the diet of the host, and that the rate of development and probability of female or male progeny was similar for most levels of ascorbic acid tested. This would indicate that as the ascorbic acid concentration increases in the pest insect the effectiveness of the wasp is likely to increase and when, by comparison with other published findings, the effectiveness of microbial pathogens is likely to decrease.

Dietary ascorbic acid requirement of juvenile ayu (Plecoglossus altivelis)

To investigate dietary ascorbic acid (AA) requirement of juvenile ayu (Plecoglossus altivelis) weighing 1.27 ± 0.02 g, eight diets were formulated with graded levels (0, 20, 40, 80, 160, 320, 640 and 1280 mg AA kg−1) of AA supplied as ascorbyl polyphosphate. Each experimental diet was fed to four-replicate groups to apparent satiation three times a day for 8 weeks. At the end of the feeding trial, fish fed AA-deficient diet showed visible AA deficiency signs and low survival. Based on the four-parameter saturation kinetics model, the calculated AA requirement levels for each dose-dependent response [weight gain, hepatic AA concentration, hydroxyproline (HyPro) concentration in skin and HyPro concentration in backbone] were 116, 226, 47 and 35 mg kg−1, respectively. Based on the maximal growth performance, a level of 116 mg AA kg−1 was recommended for commercial diet of juvenile ayu. To maintain tissue HyPro saturation and avoid AA deficiency symptoms, the minimum required dietary AA level was 47 mg kg−1. Hepatic AA saturation was considered as the most stringent criterion for determination of AA requirement.

Optimum Dietary Level of L-ascorbic Acid for Japanese Eel, Anguilla japonica

A feeding experiment was conducted to determine the optimum dietary level of ascorbic acid (AsA) for Japanese eel juveniles using L-ascorbic acid Ca based on growth, AsA content in tissues, hematology, and bactericidal activity of serum with Escherichia coli. Test diets with six levels of AsA (3, 10, 27,126, 645, and 3,135-mg/kg diet) as Ca ascorbate were fed to juvenile Japanese eels (11.0 ± 0.2 g) once a day for 8 wk. High survival rates (> 80%) were observed among all dietary treatment groups. The specific growth rates of the fish fed diets containing 3 and 10-mg AsA/kg were significantly (P < 0.05) lower than those of other groups. Liver and brain AsA contents of the fish fed diets containing 3, 10, and 27-mg AsA/kg were significantly (P < 0.05) lower than those of the fish fed diets containing 645 and 3,135-mg AsA/kg. Hemoglobin content tended to be higher in the fish fed diets containing 645 and 3,135-mg AsA/kg than those of the fish fed other diets. Hematocrit value and total serum protein content of the fish fed diets containing 645 and 3135 mg AsA/kg were significantly (P < 0.05) higher than those of the other groups. The fish fed diets containing more than 27-mg AsAlkg showed a higher bactericidal activity of serum than the fish fed the diets containing 3-mg and 10-mg AsA/kg. The optimum dietary level of AsA for the Japanese eel juveniles growth was estimated to be more than 27-mg AsA/kg. Furthermore, the inclusion of 645-mg AsA/kg or more also increased the hematocrit, hemoglobin, total serum protein value, and liver and brain vitamin C concentrations.