Effects of intramuscular injections of folic acid on serum folates, haematological status and growth performance of growing-finishing pigs

In a first trial, 48 piglets aged 5 weeks, grouped into 6 blocks of 8 pigs each, were used to determine the effect of intramuscular injections of folic acid on serum folates, haematological status, growth performance and carcass characteristics. Each block consisted of 2 pens of 4 pigs; in one pen, pigs received, by weekly intramuscular injections, an increasing volume of a solution containing 5 mg/ml folic acid, while in the other the animals were non-injected controls. The concentration of serum folates in treated pigs was 19% higher (P = 0.005) than in controls. There was no effect of treatment (P greater than or equal to 0.29) on haemoglobin and haematocrit. During the starting period, (5-11 weeks) average daily gain was not influenced by folic acid injections but feed intake and feed conversion were decreased (P = 0.07 and P = 0.05 respectively). No effect of folic acid (P greater than or equal to 0.23) was noted from 11-23 weeks of age, suggesting that the supplement was suboptimal during the growing-finishing period. In a second trial, 72 piglets aged 9 weeks were assigned to 6 blocks of 12 animals each. The following treatments were randomly distributed in each block according to a 2 x 3 factorial design: level of feeding (restricted vs ad libitum) and weekly intramuscular injections of increasing volume of solutions containing either 0, 15 or 30 mg/ml of folic acid. The variables studied were the same as in Trial 1. Concentrations of serum folates varied quadratically (P = 0.0001) with the dose injected, a plateau being attained with injections of 15 mg/ml. There was no effect of treatment (P = 0.043) on haemoglobin and haematocrit. During the growing period (9-15 weeks), no effect (P greater than or equal to 0.72) of folic acid was noted on growth performance. However, during the finishing period (15-21 weeks), folic acid given at a dose of 30 mg/ml decreased (P = 0.006) feed intake while no effect (P greater than or equal to 0.13) of the vitamin supplementation was noted on average daily gain and feed conversion. In both trials, there was no effect (P greater than or equal to 0.21) of any treatments on carcass characteristics. These results indicate that a supplement of folic acid administered by intramuscular injections was effective in increasing concentration of serum folates of starting or growing-finishing pigs. This supplement may be associated with a decrease in feed intake.     

Electrochemical determination of folic acid: A short review

Folic acid (FA) is an electroactive compound of biological origin. It helps our body to produce and maintain healthy cells. It can significantly reduce the occurrence of neural tube defects and also prevents change in DNA structure. FA deficiency can lead to various health risks. Therefore, a sensitive, specific, and reproducible way of FA detection is essential. A number of analytical methods are in practice for the quantification of FA. However, electroanalytical methods are attracting much attention because of their advantage over conventional methods, as they are fast, simple, sensitive, and cost effective. Moreover, modification of electrodes offers control over size and morphology which allows miniaturization for applicability in portable electrochemical devices.     

Biosynthesis of folic acid

Summary The influence of various vitamins on the biogenesis of folic acid has been studied in microorganisms requiring these as growth factors. In L. arabinosus, the folic acid synthesised was directly proportional to the availability of both riboflavin and pantothenic acid. The influence of cyanocobalamin on folic synthesis varied radically in different organisms. In case of the B₁₂/methionine auxotroph of E. coli there was an inverse relationship of vitamin B₁₂ to folic acid synthesis, while in Euglena the folic acid elaborated was in proportion to cyanocobalamin supplied. Synthesis of both folic acid and vitamin B₁₂ was depressed when thymine supply was adequate in the nutrition of E. coli 15 T ^-, a thymine auxotroph.     

Photogenotoxicity of folic acid

Folic acid (FA), also named vitamin B9, is an essential cofactor for the synthesis of DNA bases and other biomolecules after bioactivation by dihydrofolate reductase (DHFR). FA is photoreactive and has been shown to generate DNA modifications when irradiated with UVA (360 nm) in the presence of DNA under cell-free conditions. To investigate the relevance of this reaction for cells and tissues, we irradiated three different cell lines (KB nasopharyngeal carcinoma cells, HaCaT keratinocytes, and a melanoma cell line) in the presence of FA and quantified cytotoxicity and DNA damage generation. The results indicate that FA is phototoxic and photogenotoxic by two different mechanisms. First, extracellular photodecomposition of FA gives rise to the generation of H₂O₂, which causes mostly DNA strand breaks. If this is prevented, e.g., by the presence of catalase, DNA damage generated by intracellular FA becomes evident. The damage spectrum in this case consists predominantly of oxidatively generated purine modifications sensitive to the repair glycosylase Fpg, as characteristic for type I photoreactions, and is associated with the formation of micronuclei. In KB cells, the DNA damage is strongly enhanced after pretreatment with the DHFR inhibitor methotrexate, which prevents the loss of the chromophore associated with the intracellular reduction of FA by DHFR. The results indicate that FA is photoreactive in cells and gives rise to nuclear DNA damage under irradiation.     

Biosynthesis of folic acid

Summary It has been attempted to isolate and characterize the folate precursors in the culture filtrates of two folate-requiring organisms, Streptococcus faecalis R and Lactobacillus casei. On the basis of paper chromatography, bioautography, ultra violet absorption spectra, chemical reactions, and differential microbiological responses it has been concluded that L. casei cultures contain a compound similar to pteroic acid which can be utilized by S. faecalis R. The S. faecalis R cultures on the other hand appear to accumulate a pteridine derivative active for Crithidia fasciculata It has been confirmed that this pteridine is not derived from the folic acid usually added to the growth medium.Abbreviations PGA Pterolyglutamic acid - PABA p-aminobenzoic acid     

Biosynthesis of folic acid

Summary Biosynthesis of folic acid activity by Bacillus subtilis cell suspensions was studied with respect to substrates utilized as precursors. Among purine bases, adenine was utilized the best and not guanine although guanosine or guanylic acid were utilized efficiently. Among 3-C precursors, glyceraldehyde gave maximum synthesis of folate activity. The cells appeared to utilize p-aminobenzoate preferentially to p-aminobenzoyl-glutamate. Pteroic acid appears to be an intermediate in the synthesis of folate derivatives in this system. Ascorbic acid stimulates the synthesis to a great extent.     

A re-examination of the problem of photochemical nitrogen reduction by blue-green algae

Summary Although it was possible in the light in the absence of carbon dioxide to obtain a ratio of nitrogen fixed to oxygen evolved in nitrogen-starved cells of A. cylindrica near to 1:1.5, that quoted by other workers, ratios varying between 1:0.9 and 1:3.0 were also obtained. The amount of oxygen evolved under the same conditions by normal cells in the presence of pyruvate was increased considerably. Since the addition of pyruvate also resulted in increased carbon dioxide output in the dark with the same algal material, oxygen output in the light was attributed to the production of factors necessary for carbon assimilation.Addition of pyruvate to nitrogen-starved and normal cells in the light resulted in similar rates of oxygen evolution after an initially higher rate in the starved cells. The ratio of overall nitrogen fixed to oxygen evolved, was 1:6.6 for the starved cells and 1:6.4 for the normal cells, showing that the presence of an added substrate increased oxygen output relative to nitrogen uptake. ¹⁴CO₂ was recovered from sodium pyruvate-1-¹⁴C in flasks incubated in the dark, showing that, at least in the dark, pyruvate was decarboxylated.The interpretation of these results is that endogenous and exogenous substrates available to cells of A. cylindrica become decarboxylated and that, in the light, carbon dioxide produced may be assimilated photochemically with accompanying oxygen evolution. This interpretation has been discussed in relation to reports of photochemical nitrogen reduction in blue-green algae.