Reduced Ammonia Concentration Research Articles

Effects of narasin supplementation on dry matter intake and rumen fermentation characteristics of Bos indicus steers fed a high-forage diet.

This study evaluated the effects of narasin on intake and rumen fermentation characteristics of Bos indicus steers offered a high-forage diet for 140 d. On day 0 of the study, 30 rumen-fistulated Nellore steers [initial body weight (BW) = 281 ± 21 kg] were assigned to 30 individual pens in a randomized complete block design according to their initial BW. Animals were randomly assigned to 1 of the 3 treatments: 1) forage-based diet without narasin (CONT; n = 10), 2) CONT diet plus 13 ppm of narasin (13NAR; n = 10), and 3) CONT diet plus 20 ppm of narasin (20NAR; n = 10). The forage used was Tifton-85 (Cynodon dactylon spp.), whereas the carrier for narasin was a 50:50 mixture of soybean hull:corn. The experimental period was divided into 5 periods of 28 d each. Throughout the experimental period, total dry matter intake (DMI) was recorded daily, whereas mineral salt intake was recorded weekly. Blood and ruminal fluid samples were collected on day 0 (prior to treatment feeding), 28, 56, 84, 112, and 140 of the study. Moreover, total tract apparent nutrient digestibility was performed for a 5-d period every 28 d. No treatment effects were observed on forage, mineral, concentrate, or total DMI (P ≥ 0.22). Nonetheless, 13NAR tended to have a greater mineral intake vs. 20NAR cohorts (P = 0.08) Narasin-supplemented animals had reduced rumen acetate, Ac:Pr ratio, as well as greater (P ≤ 0.02) rumen propionate concentrations vs. CONT cohorts. Moreover, 13NAR increased rumen propionate and decreased butyrate, Ac:Pr vs. 20NAR cohorts (P ≤ 0.01). Throughout the experimental period, narasin-supplemented animals had reduced ammonia concentrations vs. CONT cohorts (P < 0.01), whereas no differences were observed between 13NAR and 20NAR (P = 0.80). No treatment or dose effects were observed (P ≥ 0.23) on DM, organic matter (OM), protein, neutral detergent fiber (NDF), acid detergent fiber (ADF), and mineral digestibility. Animals fed 13NAR had a reduced mean plasma urea concentration vs. CONT cohorts (P = 0.03), whereas no further differences were observed (P ≥ 0.12). In summary, narasin supplementation to beef steers offered a high-forage diet did not impact forage, mineral, and total DMI, as well as nutrient digestibility, whereas rumen fermentation characteristics, rumen ammonia, and plasma urea concentrations were positively impacted and lasted throughout the experimental period. Additionally, 13 ppm of narasin resulted in a reduced Ac:Pr ratio and rumen ammonia when compared to animals supplemented with 20 ppm.

Rapid enrichment and ammonia oxidation performance of ammonia-oxidizing archaea from an urban polluted river of China

Ammonia oxidation is the rate-limiting step in nitrification process and dominated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). In the present study, a highly enriched culture of AOA was obtained from urban polluted water in Shahe River, Shenzhen, China. The optimum growth conditions were identified by orthogonal analysis as 37 °C, with pH 7.0 and initial ammonia concentration of 1.0 mM. Under these conditions, the highest abundance of AOA was obtained as 4.6 × 107 copies/ng DNA. Growth of AOA in polluted river water showed significant reduction in ammonia concentration in AOA-enriched cultures without antibiotics after 10 days of incubation, while synchronous increase in nitrate concentration was up to 12.7 mg/L. However, AOA-enriched by antibiotic showed insignificant changes in ammonia or nitrite concentration. This study showed that AOB play an important role in ammonia oxidation of polluted river water, and AOA alone showed insignificant changes in ammonia or nitrite concentrations. Therefore, the ammonia oxidation performance of natural water could not be improved by adding high concentration AOA bacterial liquid.

A Simple Solution of Dissolved Ammonia Recovery Process in a Hollow-Fiber Membrane Contactor: Comparison with Experimental and Numerical Results

Ammonia in gaseous form is one of the major pollutants in waters and wastewaters. Of all the processes studied so far for the removal of dissolved ammonia from aqueous solution, hollow fiber membrane contactor-based processes have shown great potential. This method has shown to be effective to substantially reducing ammonia concentration to an acceptable value economically and efficiently. Mathematical analysis is presented in this report for the removal of ammonia dissolved in an aqueous phase to a recovery/stripping solution in a hollow fiber membrane contactor (HFMC). The membrane contactor is considered to consist of the lumen side (allowing aqueous flow) and shell side (allowing the flow of the stripping/recovery solution). An approximate analytical solution is derived for the simplified model that does not include radial diffusion of solutes (only axial mass flux is included). The predicted results of this solution are compared with the experimental data and with the numerical results in the literature over a range of operating conditions. The flow rates of the feed solution covered: 2.01 x 10 -9 to 4.7 x 10 -6 m3/s, initial concentration: 50 – 800 ppm and pH values of the solution containing ammonia: 8 - 11. The agreement is very good between the profiles of the simplified analytical solution and the earlier published experimental data. In addition, the results obtained by the analytical solution are close to the numerical solution of the complete model over a good range of operating conditions.

Odor Problems in Toilets with Reduced Ventilation Frequencies

Japan’s toilets are generally ventilated 15 times per hour. Despite the development in toilets, the ventilation frequency in toilets has not been changed in recent times. Therefore, there is a possibility that toilets are being excessively ventilated. Reducing the ventilation frequency increases the return air to the heat exchanger and improves the efficiency of the heat exchanger. For an optimal ventilation frequency, we introduce a system that could control the exhaust air using sensors. The primary issue is the odor caused by reducing the ventilation frequency. In this study, we aim to eliminate the odor as quickly as possible by providing an exhaust port at the bottom of the wall (hereinafter referred as “baseboard deodorization”). First, we examined the relationship among the odor sensor, human’s olfactory odor identification and ventilation volumes with the toilet in operation to verify the usefulness of the sensors. Next, the air environment was analyzed using computational fluid dynamics (CFD). The results of the measurements and questionnaire survey indicate a correlation between the degree of contamination in the air and the odor intensity. The CFD analyses demonstrated, even after the frequency of ventilation reduced to 5 times per hour, that the ammonia concentration obtained was equivalent to 15 times per hour. To solve the odor problem due to the ventilation reduction, it is important to evacuate air immediately after the odor is generated. Among others, it was observed that a baseboard deodorization system contributes significantly to the reduction in ammonia concentration.

Profiling of rumen fermentation, microbial population and digestibility in goats fed with dietary oils containing different fatty acids

BackgroundThe effects of the dietary oils with differing fatty acid profiles on rumen fermentation, microbial population, and digestibility in goats were investigated. In Experiment I, rumen microbial population and fermentation profiles were evaluated on 16 fistulated male goats that were randomly assigned to four treatment groups: i) control (CNT), ii) olive oil (OL), iii) palm olein oil (PO), and iv) sunflower oil (SF). In Experiment II, another group of 16 male goats was randomly assigned to the same dietary treatments for digestibility determination.ResultsRumen ammonia concentration was higher in CNT group compared to treatment groups receiving dietary oils. The total VFA and acetate concentration were higher in SF and OL groups, which showed that they were significantly affected by the dietary treatments. There were no differences in total microbial population. However, fibre degrading bacteria populations were affected by the interaction between treatment and day of sampling. Significant differences were observed in apparent digestibility of crude protein and ether extract of treatment groups containing dietary oils compared to the control group.ConclusionsThis study demonstrated that supplementation of different dietary oils containing different fatty acid profiles improved rumen fermentation by reducing ammonia concentration and increasing total VFA concentration, altering fibre degrading bacteria population, and improving apparent digestibility of crude protein and ether extract.

Essential oils from Lippia turbinata and Tagetes minuta persistently reduce in vitro ruminal methane production in a continuous-culture system

The aim of the present study was to evaluate the impact of essential oils (EO) from Lippia turbinata (LT) and Tagetes minuta (TM) as well as the rotation of both EO on fermentation parameters in vitro. Daily addition of LT, TM, or a 3-day rotation between them (TM/LT), as well as a control (without EO), was evaluated using the rumen simulation technique (Rusitec). The experiment lasted 19 days, with a 7-day adaptation period, followed by 12 days of treatment (Days 0–12). The EO were dissolved in ethanol (70% vol/vol) to be added daily to fermenters (300 μL/L) from Day 0. Daily measurements included methane concentration, total gas production, apparent DM disappearance and pH, which started 2 days before the addition of treatments. On Days 0, 4, 8 and 12 apparent crude protein disappearance and neutral detergent fibre disappearance, ammonia and volatile fatty acid concentration and composition were determined. Methane production was significantly inhibited shortly after addition of both EO added individually, and persisted over time with no apparent adaptation to EO addition. The TM/LT treatment showed a similar effect on methane production, suggesting that rotating the EO did not bring further improvements in reduction or persistency compared with the inclusion of the EO individually. Gas production, total volatile fatty acid concentration and composition and apparent crude protein disappearance were not affected by EO addition. Compared with the control, a 5% reduction of apparent DM disappearance and a 15% reduction of neutral detergent fibre disappearance were observed with the addition of EO. Only TM and TM/LT reduced ammonia concentration. Given the significant and persistent antimethanogenic activity of both EO, and the potential of T. minuta to modify nitrogen metabolism, EO from these plant species are of interest for developing new feed additives with potential application in ruminant nutrition that are also likely to be acceptable to consumers.

Effect of biochar produced from different biomass sources and at different process temperatures on methane production and ammonia concentrations in vitro

The effects of different biochars on in vitro rumen gas production and fermentation characteristics were investigated using a two (biochar inclusion level, 10 and 100 g biochar/kg substrate) x two (process temperature, 550 or 700 °C) × five (biomass source, Miscanthus straw, oil seed rape straw, rice husk, soft wood pellets or wheat straw) factorial design. The amount of biochar included in incubations had no effect on in vitro fermentation. Overall, inclusion of biochar reduced total gas production to 0.96 (P < 0.001) and methane (CH4) production to 0.95 (P < 0.001) of that in control (no added biochar) incubations. There were no differences in gas or CH4 production between the biomass sources used to produce biochar but total gas (P = 0.058) and CH4 (P = 0.010) production were slightly greater when biochar was produced at 700 rather 550 °C. Addition of biochar to incubations did not change total amounts of volatile fatty acids (VFA) or acetic acid produced during in vitro fermentation; however, the amounts of propionate (0.94; P < 0.001) and butyrate (0.96; P = 0.021) were reduced when biochar was added to incubations. Process temperature had no effect on VFA produced; however, total VFA and the amounts of acetic and butyric acids produced were influenced by biochar biomass source. Ammonia concentrations at the end of incubations were overall 0.84 of control concentrations (P < 0.001)when biochar was added. Both process temperature and biochar biomass source influenced ammonia concentrations which were greater for biochar produced at 700 than 550 °C; concentrations were lowest for biochar produced from Miscanthus straw and greatest for rice husk with oil seed rape straw, soft wood pellets and wheat straw intermediate. Adding biochars with a range of compositions to in vitro assays produced only small reductions in CH4 production. However, the absence of any negative effects of biochar coupled with the observed reduction in ammonia concentrations makes it possible that including biochar in livestock feed could be a practical means of applying biochar to pasture and soil.

Liquidation of ammonia clouds using a mobile turbine rescue and firefighting system

Given its extensive industrial use and chemical properties ammonia is a source of serious hazards in the event of its uncontrolled releases. The mobile turbine rescue and fire-fighting system (MTSRG), equipped with a special SO3-W aircraft turbine with 10 kN power and water efficiency of 6 m3/min, can be used to liquidate spatial gas clouds by diluting them with combustion gases and sorption on the surface of the produced water microdroplets. The publication presents calculations related to the effectiveness of the system during the uncontrolled release of ammonia from a pressure vessel. To estimate the performance of this system, use was made of water stream droplet size research, kinetics studies of ammonia sorption, SO3-W turbine parameters at a safe working distance, as well as results of ammonia concentration simulation using the ALOHA program. A combined simulation carried out for a rupture of DN100 pipe supplying liquid ammonia to spherical tank with a diameter of 16.6 m and filled in 70% showed that it is theoretically possible to reduce the ammonia concentration by as much as 95.75% while the vehicle is operating at a working distance of 60 meters from the rupture. The exhaust gases together with the entrained air contribute mainly to the reduction of the concentration of ammonia through the mechanism of dilution (91.6%). Water mist generated by the vehicle is theoretically responsible for the reduction of ammonia concentration by only 4.15%.

Application of mixed design models in impact of high Ammonia concentration on Plasma Immunoglobulins and Newcastle virus vaccine titer in broilers

High Ammonia concentration in broiler's houses contributed a reduction in performance, lowering in resistance and increased mortality. Four out of five Hubbard broiler groups (5 × 60) were subjected to 60 ppm ammonia for 2; 4; 6; 8 hours per day; respectively for 5 successive weeks. The impact of high ammonia concentration on biochemical; immunological and bacteriological status was assessed in 900 (150 sera, 150 plasma, 150 swab and 450 organ) samples collected post exposure. Data were analyzed using traditional and mixed model ANOVA considering repeated measures. Effect size estimates were quantified using Eta and partial Eta-squared. Broilers showed 10, 18, 32 and 41.2% mortalities at 2, 4, 6 and 8 hrs of exposure; respectively. A highly significant decline (P ˂ 0.01) was recorded in immune organs’ weight. Plasma immunoglobulins revealed a highly significant decrease (P ˂ 0.01) at 8 hrs of exposure. Newcastle virus vaccine titer revealed a highly significant decrease (P ˂ 0.01) in 4, 6 and 8 hrs of exposure. Effect size statistics revealed that mixed model ANOVA was advantageous in exhibiting the biological value of studied effects. The longer the period of exposure to ammonia beyond permissible limits, the larger negative influences can be detected. Management practice in broiler farms should include preventive measures to reduce ammonia concentrations as well as researchers should keep in mind a quantitative estimate for each effect size when conducting experimental studies.

Substrates for biofilter in recirculating system in Nile tilapia larviculture production

SUMMARY Recirculating water system (RAS), provide to reduce water usage and to improve the quality by nutrient recycling, so biofilters are used to reduce ammonia concentrations by oxidation to nitrate, by nitrifying-bacteria. Biological filters have been utilized to maintain acceptable water parameters to larvae and juveniles, by decreasing ammonia concentrations. The objective of this experiment was to evaluate different substrates for aquarium biofilter on performance of Nile tilapia (Oreochromis niloticus) larvae, and water quality. One-thousand-two-hundred Nile tilapia larvae (initial length = 11.6 ± 0.82 mm; body weight (BW) =189.0 ± 0.44mg) were randomly allotted into one of twenty 6-L aquariums (60 larvae aquarium-1) with five different biofilter (4 aquariums each biofilter): (1) control, no substrate; (2) seashell-and granitic crushed stone-substrate; (3) granitic crushed stone substrate; (4) quartz gravel substrate; and (5) porcelain-substrate. The conductivity, turbidity, pH, nitrate, nitrite and ammonia values indicate that seashell and granitic crushed-stone, and porcelain-substrates had greater process of biofiltration effectiveness. Water oxygen did not differ among treatments, with all levels within the benchmark for the tilapia larvae. Fishes reared in aquarium with quartz gravel-and porcelain substrate fishes had greater BW, total and standard length compared with its from other substrates. Porcelain-substrate biofilter is indicated for tilapia larviculture due to improved weight and length and water quality.

Addition of arabinoxylan and mixed linkage glucans in porcine diets affects the large intestinal bacterial populations.

To investigate the effects of two cereal soluble dietary fibres (SDF), wheat arabinoxylan (AX) and oat-mixed linkage glucans (MLG), on fermentative end-products and bacterial community profiles of the porcine caecum (Cae) and distal colon (DC). We hypothesised that feeding pigs these SDF would stimulate Cae and DC carbohydrate fermentation, resulting in a modification of the resident bacterial communities. Five groups of six pigs were each fed one diet based on wheat starch (WS) only, or treatment diets in which some WS was replaced by 10% AX, or 10% MLG, a combination of 5% AX:5% MLG (AXMLG), or completely replaced with ground whole wheat. Post-euthanasia, Cae and DC digesta were collected for analysis of fermentative end-products, and bacterial community profiles were determined by 16S rRNA gene amplicon 454 pyrosequencing. Across all the SDF-containing diets, predominantly in the proximal region of the large intestine, Prevotella, Lactobacillus, Mitsuokella and Streptococcus were most significantly influenced (P<0.05), while notable changes were observed for the Ruminococcaceae and Lachnospiraceae families in the Cae and DC. The addition of MLG or AXMLG had the greatest effect of influencing bacterial profiles, reducing sequence proportions assigned to the genus Clostridium, considered detrimental to gut health, with associated increases in short-chain fatty acid and reduced ammonia concentrations. This study demonstrated how the cereal SDF AX and MLG altered the large intestinal bacterial community composition, particularly proximally, further giving insights into how diets rich in specific complex carbohydrates shift the bacterial population, by increasing abundance and promoting greater diversity of those bacteria considered beneficial to gut health.

Glycine and hyperammonemia: potential target for the treatment of hepatic encephalopathy.

Hepatic encephalopathy (HE) is a neuropsychiatric disorder caused by hepatic dysfunction. Numerous studies dictate that ammonia plays an important role in the pathogenesis of HE, and hyperammonemia can lead to alterations in amino acid homeostasis. Glutamine and glycine are both ammoniagenic amino acids that are increased in liver failure. Modulating the levels of glutamine and glycine has shown to reduce ammonia concentration in hyperammonemia. Ornithine Phenylacetate (OP) has consistently been shown to reduce arterial ammonia levels in liver failure by modulating glutamine levels. In addition to this, OP has also been found to modulate glycine concentration providing an additional ammonia removing effect. Data support that glycine also serves an important role in N-methyl D-aspartate (NMDA) receptor mediated neurotransmission in HE. This potential important role for glycine in the pathogenesis of HE merits further investigations.

In vitro influence of dietary protein and fructooligosaccharides on metabolism of canine fecal microbiota.

BackgroundThe present in vitro study investigated whether the utilization of fructooligosaccharides (FOS) may influence canine fecal microbial population in presence of diets differing in their protein content and digestibility. Fresh fecal samples were collected from five adult dogs, pooled, and incubated for 24 h with the undigested residue of three diets: 1, Low protein high digestibility diet (LP HD, crude protein (CP) 229 g/kg); 2, High protein high digestibility diet (HP HD, CP 304 g/kg); 3, High protein low digestibility diet (HP LD, CP 303 g/kg) that had been previously subjected to enzymatic digestion. In the in vitro fermentation study, there were six treatments: 1) LP HD; 2) HP HD 3) HP LD; 4) LP HD + FOS; 5) HP HD + FOS; 6) HP LD + FOS. Fructooligosaccharides were added at the final concentration of 1.5 g/L. Samples of fermentation fluid were collected at 6 and 24 h of incubation.ResultsValues of pH were reduced by FOS at 6 and 24 h (P < 0.001); conversely, low protein digestibility and high dietary protein level resulted in higher pH at both sampling times (P < 0.001). At 24 h, FOS lowered ammonia (−10 %; P < 0.001) and resulted (P < 0.05) in higher concentrations of total volatile fatty acids (VFA) (+43 %), acetic acid (+14 %), propionic acid (+75 %) and n-butyric acid (+372 %). Conversely, at 24 h, low protein digestibility resulted (P < 0.01) in lower concentrations of acetic acid (−26 %), propionic acid (−37 %) and total VFA (−21 %). Putrescine concentrations were increased at 6 and 24 h of fermentation by low protein digestibility (+21 and 22 %, respectively; P < 0.05) and FOS (+18 and 24 %, respectively; P < 0.01). After 24 h of fermentation, high dietary protein level resulted in lower counts of lactobacilli and enterococci (−0.5 and −0.7 log cells/mL, respectively; P < 0.05) whereas low protein digestibility tended to increase counts of C. perfringens (+0.2 log cells/mL; P = 0.07).ConclusionsResults from the present study showed that diets rich in protein may exert negative influences on the canine intestinal ecosystem, slightly increasing the presence of ammonia and reducing counts of lactobacilli and enterococci. Moreover, the presence of poorly digestible protein resulted in lower concentrations of VFA. Conversely, administration of FOS may improve metabolism of canine intestinal microbiota, reducing ammonia concentrations and enhancing VFA production.

Interactive Effects of Indigestible Carbohydrates, Protein Type, and Protein Level on Biomarkers of Large Intestine Health in Rats.

The effects of indigestible carbohydrates, protein type, and protein level on large intestine health were examined in rats. For 21 days, 12 groups of six 12-week-old male Wistar rats were fed diets with casein (CAS), or potato protein concentrate (PPC), providing 14% (lower protein level; LP), or 20% (higher protein level; HP) protein, and containing cellulose, resistant potato starch, or pectin. Fermentation end-products, pH, and β-glucuronidase levels in cecal digesta, and ammonia levels in colonic digesta were determined. Cecal digesta, tissue weights, cecal and colon morphology, and colonocyte DNA damage were also analyzed. Digesta pH was lower, whereas relative mass of cecal tissue and digesta were higher in rats fed pectin diets than in those fed cellulose. Cecal parameters were greater in rats fed PPC and HP diets than in those fed CAS and LP diets, respectively. Short-chain fatty acid (SCFA) concentrations were unaffected by protein or carbohydrate type. Total SCFA, acetic acid, and propionic acid concentrations were greater in rats fed LP diets than in those fed HP. Cecal pool of isobutyric and isovaleric acids was greater in rats fed PPC than in those fed CAS diets. PPC diets decreased phenol concentration and increased ammonia concentration in cecal and colonic digesta, respectively. Cecal crypt depth was greater in rats fed PPC and HP diets, and was unaffected by carbohydrates; whereas colonic crypt depth was greater in rats fed cellulose. Myenteron thickness in the cecum was unaffected by nutrition, but was greater in the colon of rats fed cellulose. Colonocyte DNA damage was greater in rats fed LP diets than in those fed HP diets, and was unaffected by carbohydrate or protein type. It was found that nutritional factors decreasing cecal digesta weight contribute to greater phenol production, increased DNA damage, and reduced ammonia concentration in the colon.

Feasibility of coupling anaerobic digestion and struvite precipitation in the same reactor: Evaluation of different magnesium sources

The feasibility of coupling anaerobic digestion and struvite precipitation in the same reactor was evaluated to enhance manure anaerobic digestion methane yields through ammonia inhibition mitigation. Five different magnesium sources were tested as a struvite (ammonia sequestration agent) precursor, i.e. MgCl2, Mg(OH)2, two industrial by-products rich in MgO but with different reactivity, and a stabilizing agent. The latter was formulated in advance with the low reactivity industrial by-product and phosphoric acid. The effect of each magnesium source on anaerobic digestion as well as its struvite precipitation capacity was evaluated through biomethane potential tests. Results indicated that all magnesium sources were able to reduce ammonia concentration to different extents. However, the stabilizing agent was the unique magnesium source that did not inhibit the anaerobic digestion process. The avoidance of adding a phosphate source directly into the digester medium and the high newberyite content were the advantages of the stabilizing agent over the other magnesium sources. Finally, a series of experiments indicated that if anaerobic digestion and struvite precipitation are combined in a single reactor, stabilizing agent addition should be carried out through several small additions rather than few large additions.

Effects of hainanmycin or monensin supplementation on ruminal protein metabolism and populations of proteolytic bacteria in Holstein heifers

Three ruminally cannulated cows were used in a 3×3 Latin square design (21-d periods) to evaluate effects of hainanmycin (HAI) or monensin (MON) supplementation on ruminal protein metabolism and populations of proteolytic bacteria in Holstein heifers. The three dietary treatments were: (1) basal diet (control); (2) basal plus 20mg/heifer per day HAI and (3) basal plus 350mg/heifer per day MON. The supplementation with HAI and MON had minor effects on ruminal pH and total VFA. In general, HAI and MON decreased acetate, butyrate concentrations, and acetate to propionate ratio, and increased propionate concentration. Supplementation of HAI and Mon resulted in higher relative population sizes of the genus Prevotella and Prevotella ruminicola, and fewer Butyrivibrio fibrisolvens and hyper-ammonia-producing bacteria (P<0.05). HAI supplementation increased concentrations of peptide nitrogen and amino acid nitrogen, and reduced ammonia concentration (P<0.05), and decreased peptidase and deaminase activities (P<0.05). Overall, HAI was as effective as monensin as ionophore in regulation of ruminal protein metabolism and populations of proteolytic bacteria for dairy cows.

The effect of Yucca schidigera liquid extract on water quality and survival of Pacific Red Snapper Lutjanus peru during acclimatization

The goal of this study was to determine the effect of the liquid extract of Yucca schidigera on water quality and survival of Pacific red snapper Lutjanus peru during its transfer from wild to laboratory conditions. Three experimental groups (0.00; 0.25 and 0.75 mg of Y. schidigera liquid extract per liter of culture) were tested with four replicates using water recirculating systems. The liquid extract was dispensed every 72 h during 28 days. It was proved that Y. schidigera extract could be effective to reduce ammonia nitrogen caused by biogenic source (excretion of fish juveniles) diminishing mortality of Pacific red snapper during acclimatization process. It is recommended the use of yucca extract concentration at a dose of 0.75 mg L-1 to reduce ammonia concentration in marine water for holding red snapper juveniles.

Effects of Inorganic and Organic Fertilization on Physicochemical Parameters, Bacterial Concentrations, and Shrimp Growth in Litopenaeus vannamei Cultures with Zero Water Exchange

AbstractTo identify ways to improve water quality and shrimp production in closed systems, two parallel experiments (one in tanks and one in ponds) were conducted using Pacific white shrimp, Litopenaeus vannamei, cultures. In both experiments, the effects of inorganic (Nutrilake®) and organic (molasses) fertilization on physicochemical parameters, bacterial concentrations, and shrimp performance under zero water exchange were evaluated. Fertilization with both molasses and Nutrilake enhanced the feed conversion rate, as well as shrimp survival and production. In tanks, the shrimp survival and production rates were highest in the molasses treatment, but this effect was not observed in ponds. In ponds, fertilization with Nutrilake increased nitrogen and phosphorus concentrations more than did the controls and molasses treatments toward the end of the experiment. In tanks, fertilization with molasses reduced ammonia concentrations toward the end of the experiment, but the same effect was not observed in ponds. In ponds, fertilization reduced the proportion of Vibrio spp. bacteria, which most likely reduced the incidence of disease from these potentially pathogenic organisms. In both culture systems, fertilization increased the proportion of Bacillus spp., which most likely enhanced food availability.

Evaluations of Bacillus spp. as dietary additives on growth performance, innate immunity and disease resistance of olive flounder (Paralichthys olivaceus) against Streptococcus iniae and as water additives

Two studies were conducted to investigate the effects of dietary supplementation of three Bacillus spp. on growth performance, innate immunity and disease resistance of olive flounder against Streptococcus iniae and to examine the efficacy of Bacillus spp. on water quality reducing ammonia concentration and increasing fish survival. In the first experiment, a basal diet was prepared and regarded as a control and three other diets were prepared by supplementing one of three Bacillus spp. (B. subtilis, B. pumilus or B. licheniformis) at the dietary level of 0.5%. Triplicate groups of fish (initial body weight, 25g) were fed one of the four diets for eight weeks. Fish fed with B. subtilis containing diet showed significantly higher growth performance and feed efficiency than fish fed with the control diet. Also, significantly higher survival rates were observed in fish fed B. subtilis or B. pumilus containing diets during the feeding trial. Phagocytic activity was significantly increased in fish fed the probiotic containing diets and higher superoxide dismutase activity was observed in fish fed B. pumilus or B. licheniformis when compared to the control. However, serum lysozyme and myeloperoxidase activities did not significantly differ compared to the control. After a challenge with S. iniae, fish fed B. subtilis or B. licheniformis showed significantly higher survival rates compared to fish fed the control diet. In the second experiment, fish (30.1g) were fed a commercial diet for three weeks and then they were distributed to nine tanks at a density of 30 fish per tank (3 replicates per treatment). Fish were fasted for 5days in static water system, while one of two probiotics, B. subtilis or B. licheniformis was treated every 24h into the rearing water at the concentration of 104CFUml−1. During the trial, significantly decreased ammonia concentration and fish mortality were observed by the supplementation of B. subtilis into the rearing water. The results in these studies indicate that B. subtilis has beneficial effects on growth performance, innate immunity and disease resistance of olive flounder and quality of the rearing water.

Partial replacement of starch with acid detergent fibre and/or neutral detergent soluble fibre at two protein levels: Effects on ileal apparent digestibility and caecal environment of growing rabbits

The effects of the composition of peri-weaning diets on apparent ileal digestibility of nutrients and caecal environment were studied in growing rabbits. Eight diets were formulated according to a 2×2×2 factorial design to increase acid detergent fibre (ADF) from 230 to 290gkg−1 dry matter (DM) at the expense of mainly starch, to increase neutral detergent soluble fibre (NDSF) from 145 to 185gkg−1 DM at the expense of mainly starch, and to reduce crude protein (CP) content from 175 to 145gkg−1 DM. A total of 32 litters of eight kits were randomly assigned to the diets at 17 days of age, weaned at 28 days of age and slaughtered at 35 days of age to collect samples of ileal and caecal contents. The substitution of ADF for starch reduced the coefficient of apparent ileal digestibility (CAID) of DM (0.292 vs. 0.229; P<0.01). The substitution of NDSF for starch increased the CAID of NDSF (−0.040 vs. 0.099; P<0.01). An interaction between dietary ADF and NDSF levels was found for the CAID of CP, higher in the low ADF-low NDSF diets than in the rest (+0.074; P<0.05). The reduction of dietary CP content decreased the CAID of CP (0.578 vs. 0.525; P<0.05) and NDSF (0.086 vs. −0.038; P<0.01). Interactions between dietary ADF and NDSF levels were found affecting full caecum weight as well as DM content and pH of caecal digesta. The increase of ADF in the high NDSF diets reduced full caecum weight (−9.1gkg−1 live weight; P<0.01), increased DM content of caecal digesta (+31gkg−1; P<0.001) and reduced caecal pH (−0.10; P<0.05). In the low NDSF diets, higher ADF increased DM content of caecal digesta to a lesser extent (+16gkg−1; P<0.001) and increased caecal pH (+0.08; P<0.05). The increase of NDSF in the high ADF diets increased full caecum weight (+8.5gkg−1 live weight; P<0.01) and reduced caecal pH (−0.14; P<0.001). In the low ADF diets, higher NDSF increased full caecum weight more extensively (+15.5gkg−1 live weight; P<0.001) and reduced DM content of caecal digesta (−16gkg−1; P<0.001). Both ADF and NDSF replacing starch increased total volatile fatty acid (VFA) concentration of caecal digesta (+11.5% and +13.9%, respectively; P<0.01). The replacement with NDSF increased molar proportion of butyrate (0.095 vs. 0.112; P<0.001) at the expense of mainly acetate (0.841 vs. 0.820; P<0.001) and reduced ammonia concentration of caecal digesta (−8.1%; P<0.05). The reduction of dietary CP content decreased total VFA (−14.4%; P<0.001) and ammonia (−23.5%; P<0.001) concentrations of caecal digesta and increased caecal pH (5.87 vs. 5.93; P<0.05). Overall, the three dietary changes under study led to changes in the caecal environment which might be effective in reducing mortality rate in a context of rabbit epizootic enteropathy.