Use Of Organic Acids Research Articles

Partial and Total Substitution of Dietary Fishmeal by Conventional or Genetically Modified Soybean Meal with or without Formic Acid Supplementation for Oreochromis niloticus Fingerlings

A feeding trial was conducted to reduce the cost of diet by using two sources of soybean meal (conventional or genetically modified) instead of the expensive commercial fishmeal (FM). In the present study, commercial FM was substituted by partial (50%) or total (100%) soybean. Diets were supplemented with formic acid (FA) at level of 0 or 10 ml/kg to investigate the growth performance and feed utilization of Oreochromis niloticus. The experiment was conducted with 360 Nile tilapia fingerlings (with initial weight, 22.15 ± 2.70 g). Nine isonitrogenous 25% crude protein and isocaloric 19.28 MJ/kg gross energy experimental diets were formulated. Over the 10-weeks feeding period, formic acid supplementation elevated the growth performance and feed utilization for fish fed either 50% conventional (C-SBM50) or 50% genetically modified soybean meal (GM-SBM50). Serum ALT, AST, glucose and triglyceride values were lower in fish fed the control diet and conventional soybean in comparison with those fed genetically modified soybean meal. No obvious changes were found in micronucleus or in nuclear abnormalities for all diets compared with the control diet. FA supplementation improves the growth performance, feed utilization and biological abdominal parameters in fish fed either C-SBM50 or GM-SBM50. In spite of that, genetically modified soybean elevated the levels of ALT, AST, glucose and triglyceride. These results draw our attention to the important use of organic acids in fish diets to improve the growth performance and feed utilization. As regarding the genetically modified soybean, it needs more investigation to evaluate their effect on feeding trial on fish.

Effects of fumaric or malic acid and 9, 10 anthraquinone on digestibility, microbial protein synthesis, methane emission and performance of growing calves

This study was aimed to test whether combination of methanogens inhibitor and a hydrogen sink may result in any complementary effects in vivo. Growing calves (15; average 7- month-old, and weighing 130 kg) were arranged into 3 groups in a randomized complete block design. Treatments were: Control (no additives), FA and AQ (control + 6.5 mM of FA and AQ at the level of 4 ppm) and MA and AQ (control + 6.5 mM of MA and 4 ppm of AQ). AQ in combination with FA or MA had no effect on final BW, ADG and daily feed intake. There was no effect of supplementation of additives on intestinal flow of microbial-N, apparent digestibility of DM, OM, CF, EE, NDF, and ADF but CP digestibility increased as a result of feeding AQ and organic acids. Nitrogen intake was similar in three groups but supplementation of diet with AQ and FA or MA decreased nitrogen losses through feces and urinary losses of nitrogen also slightly declined resulting in a nonsignificant improvement of nitrogen retention in treated groups than control. Feeding AQ and OAs resulted in a significant reduction of 9.5% methane per unit DMI in animals fed AQ and MA. It can be concluded that reduction of methane production caused by feed additives in the present study was not notable and could not improve animal performance and nutrients utilization which challenges previous in vitro findings observed in the use of organic acids and methane inhibitors in combination.

Citric acid assisted phytoremediation of copper by Brassica napus L.

Use of organic acids for promoting heavy metals phytoextraction is gaining worldwide attention. The present study investigated the influence of citric acid (CA) in enhancing copper (Cu) uptake by Brassica napus L. seedlings. 6 Weeks old B. napus seedlings were exposed to different levels of copper (Cu, 0, 50 and 100µM) alone or with CA (2.5mM) in a nutrient medium for 40 days. Exposure to elevated Cu levels (50 and 100µM) significantly reduced the growth, biomass production, chlorophyll content, gas exchange attributes and soluble proteins of B. napus seedlings. In addition, Cu toxicity increased the production of hydrogen peroxide (H2O2), malondialdehyde (MDA) and electrolyte leakage (EL) in leaf and root tissues of B. napus. Activities of antioxidant enzymes such as guaiacol peroxidase (POD), superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX) in root and shoot tissues of B. napus were increased in response to lower Cu concentration (50µM) but increased under higher Cu concentration (100µM). Addition of CA into nutrient medium significantly alleviated Cu toxicity effects on B. napus seedlings by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in CA-treated plants seems to play a role in capturing of stress-induced reactive oxygen species as was evident from lower level of H2O2, MDA and EL in CA-treated plants. Increasing Cu concentration in the nutrient medium significantly increased Cu concentration in in B. napus tissues. Cu uptake was further increased by CA application. These results suggested that CA might be a useful strategy for increasing phytoextraction of Cu from contaminated soils.

Use of organic acids in acne and skin discolorations therapy

Acne is one of the most frequent skin disorders that occurs in puberty, but often adults also have acne. The most important factors responsible for acne are elevated production of sebum by hyperactive sebaceous glands and blockage of the follicle because of hyperkeratosis [14]. The third etiopathogenic factor of acne is excessive microflora reproduction [8]. The most significant bacterium that is responsible for formation of skin lesions is Propionibacterium acnes, a rod-shaped Gram-positive and aerotolerant anaerobic bacterium. It is estimated that P. acnes is responsible for acne in approximately 80% of people aged 11 to 30 [27,40]. Even healed skin lesions can often cause skin discolorations and scar formation [51]. Exfoliating chemical substances that are commonly used in dermatology and cosmetology are organic acids. Exfoliating treatment using organic acids is called "chemical peeling" and consists of controlled application of those substances on the skin [38]. The depth of exfoliation depends on organic acid concentration, type of substance and contact time with the skin [41]. Using exfoliating agents seems to be helpful in excessive keratinization - one of several factors responsible for acne. Moreover, epidermis exfoliation is a popular method of removing skin discoloration [22]. Considering chemical structure, exfoliating substances that are most often used in cosmetology contain alpha-hydroxyacids (glycolic acid, lactic acid, mandelic acid and citric acid), beta-hydroxyacids (salicylic acid) and other organic acids, such as trichloroacetic acid and pyruvic acid [47]. In this article, a literature review of use of organic acids in acne and skin discoloration therapy is presented.

Enhancement Of Electro-Osmotic Flow During The Electrokinetic Treatment Of A Contaminated Soil

The electrokinetic remediation of contaminated soils relies in two main transport mechanisms: electromigration and electro-osmosis. The electro-osmotic flow depends on fluid characteristics (dielectric constant and viscosity) and soil surface characteristics represented by Z-potential, as well as voltage gradient. In this work, the influence of voltage gradient in the development and maintenance of electro-osmotic flow is studied. The voltage gradient directly affected the electro-osmotic flow but it also affected the geochemistry of soil that had a critical effect on electro-osmosis. It was demonstrated that 1V/cm resulted in the development and maintenance of a large electro-osmotic flow. The use of organic acids, such as citric acid, induced large electro-osmotic flow due to the interaction of the organic acids with the soil particles. The use of citric acid was considered to be very promising for large-scale operation.

Agronomic Application of Olive Mill Wastewater with Rock Phosphate Influence Soil Phosphorus Availability, Arbuscular Mycorrhizal Fungal Colonisation and Olive Tree Performance under Long-Term Field Conditions

The use of organic acids and phenolic compounds that are present in olive mill wastewater (OMW) represents a new perspective in rock phosphate (RP) research and a possible solution for the recycling of the OMW. To test the hypothesis that OMW applied in combination with Gafsa RP to olive tree plants can affect P mobilisation from RP to olive trees, a field experiment was conducted to evaluate the potential use of OMW with RP as soil amendment on olive tree alkaline soils. Treatment included three levels of OMW and RP application: M0 (non-amended control), M1PN (30 m3 ha-1 of OMW+150 kg ha-1 of RP) and M2PN (60 m3 ha-1 of OMW+150 kg ha-1 of RP). Five years after the start of the experiment, the available phosphorus decreased significantly. Amended olive trees had lower rate of photosynthates compared to the control, mostly due to decreased sink demand for carbon by the root. The biomass of arbuscular mycorrhizal (AM) fungi and the development of colonisation in the olive tree roots decreased dramatically by the application of OMW and RP. Phenols accumulation in leaves was significantly higher in the OMW and RP amended soils, whereas total chlorophyll, chlorophyll a, and chlorophyll b in olive trees leaves decreased significantly after agronomic application of OMW and RP. Taken with data from experiments in field conditions, our results suggest that the use of OMW in combination with RP, in order to mobilise P from RP to olive trees, are expected to have a major negative impact on plant performance.

SLURRY TREATMENT WITH FOOD INDUSTRY WASTES FOR REDUCING METHANE, NITROUS OXIDE AND AMMONIA EMISSIONS

Livestock manure is the main source of ammonia (NH3) emissions and an important source of greenhouse gases (GHG) especially methane (CH4) and nitrous oxide (N2O). Ammonia emissions contribute to eutrophication and acidification of water, soils and ecosystems. The greenhouse gases contribute to the global warming. These gaseous emissions can be reduced by controlling the pH-value of manure. Acidifying the manure can reduce CH4, N2O and NH3 emissions. Inorganic acids are feasible, but have several disadvantages, e.g. soil contaminants. The use of organic acids is an efficient but expensive method; therefore using the food industry wastes which already contain organic acids is highly feasible. The objective of this research is to investigate the effects food industry wastes as manure additives on the emissions of CH4, N2O and NH3. Dairy cattle manure was treated with food industry wastes (whey and waste of citrus and orange juices industry) and the gas flux of CH4, N2O and NH3 were quantified using a specially designed gas detection system which consists of several flasks and a multi-gas monitor. The results showed that the gas fluxes emitted from manure treated with waste of citrus juice industry were 13, 0.219 and 2.523 g m-2 day-1 for CH4, N2O and NH3 respectively. The gas fluxes emitted from manure treated with waste of orange juice industry were 13.58, 0.223 and 2.581 g m-2 day-1 for CH4, N2O and NH3 respectively. The gas fluxes emitted from manure treated with whey were 17.45, 0.279 and 3.063 g m-2 day-1 for CH4, N2O and NH3 respectively. The gas fluxes emitted from the control sample (mixture of manure and water) were 58.21, 0.347 and 18.9 g m-2 day-1 for CH4, N2O and NH3 respectively. Consequently, manure treatment with food industry wastes enabled high reduction rates of gaseous emissions from manure.

Use of organic acids and competitive exclusion product as an alternative to antibiotic as a growth promoter in the raising of commercial turkeys

A study was conducted to investigate the effects of organic acids (OA) and competitive exclusion product (CE) on growth performance, intestinal morphology, and concentration of volatile fatty acids in the cecal content. The experiment lasted for 10 wk. Four hundred twenty 1-d-old female commercial cross turkey poults (British United Turkeys, BUT Big 9) were distributed into 4 treatments with 5 replicates/pen of 21 birds each. The birds were fed a basal diet without growth promoter (control), diet with lincomycin (44 mg/kg), diet with organic acids (2 g/kg), and diet with product of CE (109 cfu/kg). Dietary levels of other nutrients, housing, and general management practices were similar for all treatments. On the first week (d 0–7), the BW and BW gain of the birds that fed diets with OA were lower than in the control group. In the fattening phase (d 28–70), the feed intake of the OA-treated group was lower than compared with the control. The birds that received diet with OA and CE product presented higher concentrations of propionic acid, at 14 d, and butyric acid in cecal content at 28, 56, and 70 d, compared with the control. Dietary inclusion of additives had no significant effects on intestinal villus height, crypt depth, and villus:crypt ratio. Organic acids had negative effects either on early gain or feed intake throughout the study. Because the test was conducted under controlled experimental conditions, the additives that showed results similar to those found by using antibiotics should be studied further in commercial farms to obtain results that can be incorporated into practice.

Impact of thermal and organic acid treatment of feed on apparent ileal mineral absorption, tibial and liver mineral concentration, and tibia quality in broilers

Minerals play an important role for growth and bone stability in broilers. Thermal treatment and inclusion of organic acids in feed may affect the mineral absorption and tibial quality in broilers. The study was conducted to investigate the effect of thermal processing of feed including pelleting (P), long-term conditioning at 85°C (L), and expanding at 130°C (E) without and with 1.5% of an acid mixture containing 64% formic and 25% propionic acid on the apparent ileal absorption (AIA) of calcium, phosphorus, magnesium, potassium, sodium, iron, copper, manganese, and zinc, their concentrations in liver and tibia, as well as various tibial quality parameters in broilers. In total, 480 one-day-old Cobb broiler chicks were assigned using a completely randomized design with a 3 × 2 factorial arrangement. The ileal digesta, liver, and tibia were collected at d 35. The AIA of calcium and sodium was improved in group E compared with L (P ≤ 0.02 and P ≤ 0.01). Group P and E showed higher AIA for potassium than L (P ≤ 0.01). Bone ash content was increased in group E compared with L (P ≤ 0.04). The BW to bone weight ratio was lower and tibial zinc content was higher in group P compared with E (P ≤ 0.05). Tibial iron content was higher in group L than E (P ≤ 0.03). Acid addition did not affect AIA, mineral content in tibia, or tibial quality parameters. Thermal and acid treatment did not affect mineral concentrations in the liver, except an inconsistent interaction effect for DM content and sodium (P ≤ 0.03 and P ≤ 0.04, respectively). In conclusion, long-term thermal treatment reduced AIA of some minerals compared with short-term thermal treatments, but had no impact on tibia composition. Acid inclusion had no effect on AIA of minerals and tibia quality. Thermal treatment and the use of organic acids can therefore be considered as safe with regard to their impact on bone development in broilers.

Control of Salmonella Enteritidis in turkeys using organic acids and competitive exclusion product.

To evaluate the use of organic acids (OAs) and competitive exclusion (CE) product administered continuously in the feed and transiently in drinking water on the control of Salmonella enterica subspecie enterica serotype Enteritidis (SE) prior to slaughter. The influence of treatments were evaluated on pH, population of the lactic acid bacteria (LAB) and bacteria of the family Enterobacteriaceae, concentration of volatile fatty acids and SE colonization in the crop and caecum. The birds were challenged with SE 24h before being slaughtered, and then, the caeca and crop were removed and subjected to SE counts. Continuous administration of OAs reduced the population of bacteria from the Enterobacteriaceae family in both crop and caecum, positively influenced the butyric acid concentration and reduced SE colonization in the caecum. The diet supplemented with CE product positively influenced the quantity of LAB in the crop and caecum, elevated the butyric acid concentration and reduced both Enterobacteriaceae quantity and SE colonization in the caecum. There was no effect from administering the treatments via drinking water on the variables measured. Continuous supplementation in feed with OAs and CE product reduced SE colonization of the caeca. Supplementation of OAs and CE product in diet to turkeys can reduce the SE load, potentially leading to a lower contamination risk of meat during slaughter.

Stabilization mechanism for sands treated with organic acids

Contractors tout the use of organic acids for soil improvement even though the underlying stabilization mechanism is not well understood. Strength, stiffness, and chemical tests were conducted on two sandy materials treated with a commercial organic acid mixture to evaluate the effectiveness and stabilization mechanism involved. After curing for 28 days, tests show a moderate increase in unconfined compressive strength, approximately two-fold, and a large increase in constrained modulus, approximately one order of magnitude. X-ray diffraction and chemical analyses do not suggest traditional pozzolanic reactions as the source of improvements in the treated specimens. Test results suggest the organic acid solution promotes microbe growth and thus an increase in organic matter within the sand skeleton. This reduction in void space increases relative density to levels above the maximum unit weight of the host sand, resulting in higher soil strength and stiffness.

Sulfuric acid-modified poly(ethylene glycol): an efficient, biodegradable, and reusable polymeric catalyst for synthesis of spiro oxindole derivatives in aqueous medium

A versatile, novel, and environmentally benign strategy has been successfully developed for synthesis of oxindoles, an important class of potentially bioactive compounds. Sulfonated poly(ethylene glycol) was used as inexpensive and recyclable acidic catalyst. The products were obtained in water, an excellent solvent in terms of environmental impact, in high yield, by one-pot reaction of malononitrile, 1,3-dicarbonylcoumarin or 4-hydroxycoumarin derivatives, and isatins. This new method totally avoids the use of organic acids and toxic or expensive solvents.

Effect of Organic Acids and Probiotic on broiler Performance, Some Blood Parameters and Control of E. coli

One hundred, one-day old broiler chicks were divided into four equal groups (25 each). The 1st group kept as control, non infected,, chicks in 2nd, 3rd and 4th groups were experimentally infected with E coli (0.3 ml via nasal route of cultural suspension of E. coli O78 contain 3X107viable organism/ml) at 20 day of age. Chicks in 2nd, group infected with E coli only. Chicks in 3rd and 4th groups supplemented with 1ml formic acid, 1ml probiotic/ liter drinking water respectively from 1st to 35th day of age and infected with E coli . At 1st day post supplementation 5 chicks in all groups were weighted individually for calculation weight gain and feed conversion rate. Swabes from cloaca and trachea were collected from all chicks for reisolation of E coli . Study the effect of organic acids and probiotic in mortality rate. Blood samples were collected at 1st &7th day post supplementation for hemato-biochemical analysis Broiler chicks infected with E coli showed typical clinical signs of colibacelosis and mortality rate 24%, A significant reduction in body weight, lymphocytes, monocyts, eosinophils, basophils, serum total protein, albumin, total, a & g globulin and a significant rise in feed conversion rate, leukocytic count, heterophils b globulin, AST, ALT, ALP, uric acid and creatinine levels. Also, beside insignificant reduction in phagocytosis, killing%, IgG, IGA and IgM were recorded. E. coli was reisolated from all infected chicks Chicks infected with E coli and supplemented with organic acid or probiotic show less clinical signs, mortality rate was 4% coupled with reduction in reisolation of E. coli associated with significant elevation in weight gain, phagocytosis, killing %, IgG, IGA, IgM, total protein, albumin, a, b and g globulin beside significant reduction in feed conversion rate and insignificant increase in leukocytic count, heterophils, lymphocyte, monocyte, eosinophils, basophils, A/G ratio, AST, ALT, ALP, uric acid and creatinine. It could be concluded that the use of organic acid and probiotic reduced E. coli in digestive tract of broilers and improve body performance, immune response and some biochemical parameters.

Improving Phosphorus Use Efficiency Through Potato Rhizosphere Modification and Extension

Phosphorus (P) fertilization is essential for societal sustainability. However, plant P uptake is inefficient due to poor soil P solubility, especially for the potato (Solanum tuberosum L.) plant due to its relatively poor rooting efficiency. Phosphorus use efficiency (PUE) can be increased with rhizosphere modifications such as: (1) raising the bulk pH of acid soils, (2) placement of fertilizer in the rhizosphere by broadcast incorporation and/or, especially, as a concentrated band, (3) use of slow and controlled release P fertilizers, (4) use of organic acids to increase P solubility in alkaline soils, (5) use of an acid polymer, and (6) extending the effective rhizosphere zone via any practice that fosters root growth, such as through promotion of mycorrhizal development. Alone or in combination, these techniques offer an opportunity to increase PUE.

An organic acid-tolerant HAA1-overexpression mutant of an industrial bioethanol strain of Saccharomyces cerevisiae and its application to the production of bioethanol from sugarcane molasses

Bacterial contamination is known as a major cause of the reduction in ethanol yield during bioethanol production by Saccharomyces cerevisiae. Acetate is an effective agent for the prevention of bacterial contamination, but it negatively affects the fermentation ability of S. cerevisiae. We have proposed that the combined use of organic acids including acetate and lactate and yeast strains tolerant to organic acids may be effective for the elimination of principally lactic acid bacterial (LAB) contamination. In a previous study employing laboratory S. cerevisiae strains, we showed that overexpression of the HAA1 gene, which encodes a transcriptional activator, could be a useful molecular breeding method for acetate-tolerant yeast strains. In the present study, we constructed a HAA1-overexpressing diploid strain (MATa/α, named ER HAA1-OP) derived from the industrial bioethanol strain Ethanol Red (ER). ER HAA1-OP showed tolerance not only to acetate but also to lactate, and this tolerance was dependent on the increased expression of HAA1 gene. The ethanol production ability of ER HAA1-OP was almost equivalent to that of the parent strain during the bioethanol production process from sugarcane molasses in the absence of acetate. The addition of acetate at 0.5% (w/v, pH 4.5) inhibited the fermentation ability of the parent strain, but such an inhibition was not observed in the ethanol production process using ER HAA1-OP.

The Effects of a Pickling Process on the Reduction of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus Inoculated onto Hard‐Cooked Eggs

AbstractTraditional methods of food preservation, such as pickling, have reemerged as popular approaches for home and commercial food processing. The process of pickling hard‐cooked eggs (HCE) can be an effective method of preventing the growth and survival of pathogenic microorganisms. Because of the variety of pickling processes, HCE manufacturers must validate their pickling process for Food and Drug Administration (FDA) approval and demonstrate 5‐log reductions of pathogens associated with the product. In this study, a rapid one‐step pickling process was evaluated for its ability to reduce Salmonella spp., Listeria monocytogenes, Staphylococcus aureus and Escherichia coli O157:H7 inoculated onto HCE for 14 days at room temperature. All pathogens inoculated onto HCE were reduced by (>5.0 logs) within 24 h and were undetectable following enrichment. The data obtained in this study may be of interest to regulatory officials and processors of HCE seeking pathogen reduction validation for their products.Practical ApplicationsPickling of HCE is an effective preservation method capable of preventing pathogen growth and survival. Although the use of organic acids for food preservation is not a new concept, few published studies have scientifically validated the ability of pickling methods to inhibit pathogen growth and survival on specific foods. Because of the regulatory requirements set forth by the FDA, acidified foods sold commercially must be validated through scientific studies, which demonstrate 5‐log reductions of pathogens associated with the product. Previous studies have utilized a two‐step pickled egg pickling process and demonstrated complete kill of various pathogens within 96 h. In this study, we evaluate a rapid one‐step pickling process utilizing a reformulated pickling solution and produce a complete kill of selected pathogens within 24 h, drastically reducing the cost and increasing the efficiency of a commercial pickled egg pickling process.

The different catalytic behaviour in the propane total oxidation of cobalt and manganese oxides prepared by a wet combustion procedure

Cobalt oxide and manganese oxide catalysts have been prepared through aqueous synthesis using a wet combustion procedure. These materials have been tested as catalysts for the total oxidation of propane. It has been observed a different catalytic behaviour between cobalt and manganese oxides although for both oxides a very high catalytic activity has been obtained. Cobalt oxides prepared by the wet combustion procedure are less reactive than a simple cobalt oxide prepared without the addition of organic acids. However, in the case of manganese oxide the use of organic acids highly increases the catalytic activity. The different catalytic behaviour has been related to the variation of the surface characteristics and also to the crystalline phases formed. The activity of Co catalysts has been observed to be mainly determined by the surface area as the specific activity of all cobalt oxide catalysts is comparable. This fact has been related to the similar bulk and surface redox catalyst characteristics. In the case of manganese oxide the specific reaction rate is remarkably higher in those catalysts prepared by wet combustion and this has been linked to the presence of a reduced phase and surface. The most active manganese oxide catalysts are those that present the best redox properties and the highest oxygen mobility.

Effect of Corn Particle Size and Inclusion of Organic Acid in The Diet on Growth Performance and Gastrointestinal Structure in Young Chicks

The effect of 3 corn particle sizes (dgw: 375, 1117, and 2402 µm) combined with or without organic acids (0.3 g/kg of Galliacid S®) was investigated on broilers from day 1 to day 21; 540 1-day old Ross 708 males were raised in 36 pens (3x2 factorial design, 6 blocks each). We measured: body weight, feed intake, feed conversion ratio, liver weight, pH weight and height of empty gizzard, pH and length of intestine and caeca, height and width of ileal villi, crypt depth/gland diameter, total bacteria count. Different corn particle sizes and organic acid supplements only affected feed intake (days 14 and 21), feed conversion ratio (day 14), villus height, and crypt depth. On day 21, fine milling had negative effects on body weights compared with larger feed particle size (816 vs 848 and 844 g); acidic additive had a positive effect on broiler growth (859 vs 813 g). Length of small intestinal villi and crypt depth were affected by both particle size and organic acids (fine to coarse small intestinal villi: 1869a, 1401c, and 1039d µm in non-acidified; 1708b, 1535c, and 942e µm in acidified. Fine to coarse crypt depth: 102ab, 98b; 65c µm in non-acidified; 106a, 70c, and 66c µm in acidified). No difference was observed in total bacteria counts of the gut in relation to the different treatments. Use of organic acids during starter phase is useful, especially when the milling process is inappropriate.

Phytogenic additives and organic acids in broiler chicken diets

The experiment evaluated the influence of isolated or associated phytogenic additives (PA) and organic acids (OA) on nutrient digestibility, performance and carcass characteristics of broiler chickens. Two experiments were conducted in a completely randomized design with a 2 × 2 + 1 factorial arrangement of treatments (with or without PA × with or without OA + antibiotic performance enhancer and anticoccidial). In the first experiment, two metabolic tests were conducted to determine the metabolizability coefficients of the nutrients of starter and growth diets. In the second experiment, 2520 one-day-old chicks were housed in 40 experimental units to evaluate the performance and carcass characteristics. The phytogenic additives and organic acids, isolated or associated, improve the nutrient digestibility of the diet and replace the growth- promoting antibiotics. The use of organic acids isolated or associated with phytogenic additives in broiler diets improves broiler performance in comparison with free antibiotic performance enhancer at 42 days of age. Isolated or associated phytogenic additives and organic acids provided better carcass characteristics.

Use of organic acids in the composting of municipal solid waste: a pilot-scale study

Compost made from municipal solid waste (MSW) contains heavy metals that can interfere with the use of organic amendment in soil. In order to find effective ways to reduce the potential risk of heavy metals, we have investigated a novel approach by use of organic acid during MSW composting. Citric and oxalic acid dissolutions (0.25 mol·l−1) were used at determined ratios (kg dried MSW: cm3 acid). Cr and Ni concentrations were similar in compost, independent of acid contribution. By contrast, Cu concentrations decreased by 63% (at citric acid ratio 1:15), 65% (at citric acid ratios 1:20 and 1:40) and 83% (at oxalic acid ratio 1:40); furthermore, Pb concentrations reduced by 71% (at citric acid ratios 1:20 and 1:40 and at oxalic acid ratio 1:40) and Zn concentrations reduced by 67% (at citric acid ratios 1:10 and 1:20) and 70% (at oxalic acid ratio 1:40). The total metal mass decreased by an average of 12% in the compost fraction, whereas the total percentage of the residual fraction increased by an average of 20%. The acid addition in the studied ratios improved compost quality without negatively influencing biostabilization.