Dietary Folic Acid Requirement Research Articles

Dietary folic acid requirement of fingerling Channa punctatus (Bloch) based on growth, protein productive value and liver folic acid concentrations

The aim of the study was to carry out a feeding trial to evaluate the dietary folic acid requirement of fingerling Channa punctatus (4.88 ± 0.74 g) by measuring the changes in growth indices and liver folic acid concentrations fed purified diets (450 g/kg CP, 18.39 kJ/g GE) containing seven doses of folic acid (0, 0.25, 0.5, 0.75, 1.0, 1.25 and 1.5 mg/kg diet) to triplicate groups until satiation for 12 weeks. A significant cubic response of percent weight gain per cent (PWG), feed conversion ratio (FCR), protein efficiency ratio (PER), protein production value (PPV) and RNA/DNA ratio was recorded and improved with the increasing doses of dietary folic acid up to 0.75 mg/kg, whereupon the response attained a plateau. Hemoglobin (Hb), hematocrit (Hct), red blood corpuscles (RBCs) counts, mean cell hemoglobin (MCH) and mean cell volume (MCV) improved as the dietary folic acid concentration increased from 0 to 0.75 mg/kg diet and then response reached an almost constant. Superoxidase dismutase and catalase activities also supported the pattern of growth and hematological indices whereas hepatic thiobarbituric acid reactive substances (TBARS) concentration showed reverse pattern. A direct significant cubic association of liver folic acid concentrations to the increasing doses of dietary folic acid up to 1.0 mg/kg was evident. The precise estimate of dietary folic acid requirement of fingerling C. punctatus was made by subjecting the PWG, PPV and liver folic acid concentrations against different doses of dietary folic acid to broken-line analysis which revealed the requirement in the range of 0.74–1.15 mg/kg.

Effects of dietary folic acid on growth, antioxidant capacity, non-specific immune response and disease resistance of juvenile Chinese mitten crabEriocheir sinensis(Milne-Edwards, 1853)

An 8-week study was conducted to determine folic acid requirement and its effect on antioxidant capacity and immunity in juvenile Chinese mitten crab Eriocheir sinensis (Milne-Edwards, 1853), followed by a challenge assay with the pathogen Aeromonas hydrophila for 2 weeks. Folic acid was added to a basal diet at seven levels (0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 mg folic acid kg−1 diet), and a diet free of folic acid and vitamin B12 was also included as a control. Crabs were fed twice daily in 32 tanks with 7.76–8.17 mg oxygen L−1, 25.0–31.0 °C and 7.5–8.3 pH. Growth and feed efficiency were significantly greater in crabs fed ≥2.0 mg folic acid kg−1, but not significantly different between crabs fed diets >2.0 mg folic acid. The superoxide dismutase activity and glutathione S-transferase activity were highest in crabs fed ≥2.0 mg folic acid kg−1, followed by those fed 0.5 and 1.0 mg folic acid kg−1, and the control diet. The malondialdehyde content was highest in crabs fed the control diet, followed by those fed 0 mg folic acid kg−1, and the lowest value occurred in those fed ≥0.5 mg folic acid kg−1. Phenoloxidase activity and total haemocytes were significantly higher in crabs fed ≥2.0 mg folic acid kg−1 than other diets. Crabs fed 2.0 mg folic acid kg−1 had the highest lysozyme, acid phosphatase and alkaline phosphatase activities but the lowest cumulative mortality. The optimum dietary folic acid requirement by E. sinensis was estimated at 2.29–2.90 mg kg−1 diet.

Dietary folic acid requirement of juvenile abalone Haliotis discus hannai Ino

A 16-week growth study was conducted to determine the dietary folic acid requirement of juvenile abalone (initial mean weight 482.2±2.2mg). Six semi-purified diets were formulated to contain graded levels of folic acid (0.06, 1.44, 2.86, 5.88, 14.27 and 35.71mg/kg). Each diet was fed to three replicate tanks of abalone in a re-circulated water system. The results showed that the weight gain rate (WGR) was significantly increased when dietary folic acid contents increasing from 0.06 to 2.86mg/kg (P<0.05). Higher dietary folic acid (2.86–35.71mg/kg) did not result in further increase of WGR. When dietary folic acid increased from 0.06 to 5.88mg/kg, the viscera folic acid concentration (VFAC) significantly increased (P<0.05). And then, there were no significant differences in VFAC among treatments as dietary folic acid contents increased from 5.88 to 35.71mg/kg. Dietary folic acid did not significantly influence survival and the soft body compositions of abalone. Based on WGR and VFAC, broken-line analysis showed that dietary folic acid requirements of abalone were 2.62 and 5.29mg/kg, respectively.

Dietary folic acid requirement of grouper, Epinephelus malabaricus, and its effects on non-specific immune responses

To quantify the dietary folic acid (FA) requirement of grouper, Epinephelus malabaricus, and its effects on non-specific immune responses, FA was added to a basal diet at 0, 0.4, 0.8, 1.2, 2, 4, 6 and 10 mg FA/kg, providing actual dietary values of 0, 0.39, 0.72, 1.03, 1.89, 3.36, 5.85, and 9.52 mg FA/kg, respectively for a total of 8 experimental diets. Each diet was fed to triplicate groups of fish (initial body weight: 7.28 ± 0.03 g) in a recirculating seawater rearing system for 8 weeks. Weight gain (WG) was highest ( P < 0.05) in fish fed diets with 0.72, 1.03 and ≥ 3.36 mg FA/kg, followed by 0.39 mg FA/kg, and lowest in fish fed the FA-free control diet. Fish fed diets with ≥ 0.72 mg FA/kg had higher feed efficiency (FE) but lower hepatosomatic index (HSI) than fish fed the control diet. Fish fed diets with ≥ 0.72 mg FA/kg had highest hepatic FA concentration, followed by 0.39 mg FA/kg, and lowest in fish fed the control diet. Hepatic thiobarbituric acid-reactive substance (TBARS) value was highest in fish fed the control diet, followed by 0.39 mg FA/kg diet, and lowest in fish fed diets with ≥ 0.72 mg FA/kg. Leukocyte superoxide anion (O 2 −) production ratio was higher in fish fed diets with ≥ 0.72 mg FA/kg than that in fish fed diets with ≤ 0.39 mg FA/kg. Fish fed diets with ≥ 0.72 mg FA/kg had higher plasma lysozyme activity than fish fed the control diet. Analyses of WG, HSI, hepatic FA concentration and hepatic TBARS value indicate that the optimal dietary FA level for juvenile grouper is about 0.8 mg FA/kg diet, this dietary level is also adequate for non-specific immune responses of the species.

Dietary folic acid requirement determined for grass shrimp, Penaeus monodon

A feeding trial was conducted to determine the dietary folic acid requirement of juvenile grass shrimp, Penaeus monodon. Purified basal diets were formulated using vitamin-free casein as the protein source. Graded levels (0, 1, 2, 5, 10, 15, 30, and 60 mg folic acid/kg diet) of folic acid were added to the basal diet, resulting in eight dietary treatments in the experiment. Each diet was fed to three replicate groups of shrimp initially averaging 0.79±0.01 g for 8 weeks. Shrimp fed diets supplemented with ≧2 mg folic acid/kg diet had greater ( P<0.05) weight gain and hepatopancreatic folic acid concentrations than shrimp fed the unsupplemented control diet. Feed efficiency (FE) was highest in shrimp fed the diets supplemented with ≧2 mg folic acid/kg diet, followed by the groups fed 1 mg/kg, then the control group. Hepatosomatic index (HSI) was highest in shrimp fed the control diet, followed by 1 mg folic acid/kg and lowest in shrimp fed diets supplemented with ≧2 mg folic acid/kg. Weight gain percentage, hepatopancreatic folic acid concentration and hepatosomatic index of the shrimp analyzed by broken-line regression indicated that the adequate dietary folic acid concentration in growing P. monodon is 1.9–2.1 mg/kg diet.

Dietary folic acid requirement for maximum growth of juvenile tilapia Oreochromis niloticus x O. aureus

: A feeding trial was conducted to estimate the dietary folic acid requirement of juvenile tilapia, Oreochromis niloticus×O. aureus. Purified basal diets with eight levels (0.0, 0.3, 0.6, 1.0, 3.0, 6.0, 10.0, 20.0 mg/kg diet) of supplemental folic acid were fed to tilapia (mean initial weight 0.41 ± 0.01 g) for 8 weeks. Each diet was fed to three replicate groups of fish reared in a closed recirculating system. Results indicated that weight gain and feed efficiency (FE) were significantly (P < 0.05) greater in fish fed ≥1.0 mg folic acid/kg diet than fish fed 0.3 mg folic acid/kg diet or the unsupplemented control diet. Mortality of fish was not affected by dietary treatment. Hepatic folic acid concentration increased with an increase in dietary folic acid and values were significantly higher in fish fed ≥6.0 mg folic acid/kg diet than fish fed the control diet. An analysis of the weight gain percentage by broken-line regression indicates that the adequate dietary folic acid requirement in juvenile tilapia is 0.82 mg/kg diet.

Folic acid requirements of broilers

1. Dietary folic acid requirements of broilers were studied in three experiments using wheat- and maize-based practical diets. Requirements were assessed on the basis of performance and metabolic criteria. 2. Growth and food conversion efficiencies were optimised with supplements of 1.5 mg folic acid/kg added to basal mash starter diets. The dietary folic acid requirement of broilers was estimated to be in the range of 1.7 to 2.0 mg/kg. 3. Red blood cell phosphoribosylpyrophosphate concentrations and dihydrofolate reductase activities did not show consistent changes over the range of dietary folate concentrations studied but plasma folate concentrations responded markedly to dietary folate supplementation. 4. Adding choline to diets in amounts greater than the normal requirement did not spare the requirement for folic acid. 5. It is suggested that minimum folic acid supplements for pelleted practical diets should be in the order of 2.5 to 3 mg/kg.

The Dietary Requirement of Young Rainbow Trout (Oncorhynchus mykiss) for Folic Acid

We sought to determine the dietary folic acid requirement of young rainbow trout using growth indices supported by measurements of tissue folate concentrations. The investigation was conducted with purified diets that had, by assay, basal folic acid levels of 0.08 and 0.16 mg/kg in the first and second, respectively, of two experiments. Each experiment was started with fry (initial mean weight, 1.4 and 2.8 g/fish in Experiments 1 and 2, respectively) and was conducted at a water temperature of 15 degrees C. Experiment 1 lasted 18 wk and Experiment 2 lasted 16 wk. Recovery tests (of 8 wk duration, performed on fish fed the unsupplemented diet) and pair-feeding showed that the unsupplemented diet led to a folate-specific deficiency condition in which the main hematological abnormality was the appearance of misshapen nuclei in a small proportion (2.3%) of erythrocytes. Dietary requirements were shown not to exceed 0.3 and 0.6 mg folic acid/kg (17 and 33 micrograms/MJ digestible energy) for optimizing survival and growth indices, respectively. We conclude that the dietary folate requirement of the trout is comparable to that of other vertebrates for the purpose of achieving maximal weight gain.