Effect of ractopamine and conjugated linoleic acid on performance of late finishing pigs.

The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.

Dietary L-arginine supplementation increased mammary gland vascularity of lactating sows.

The present study aimed to evaluate the mechanisms modulated by dietary arginine supplementation to sows during lactation regarding antioxidant capacity and vascularization of mammary glands. At 109 days of gestation, animals were transferred to individual farrowing crates equipped with manual feeders and automatic drinker bowls. Environmental temperature and humidity inside the farrowing rooms were registered every 15 min. At farrowing, sows were assigned in a completely randomized design to a control diet (CON) or the CON diet supplemented with 1.0% L-arginine (ARG). A total of three gilts and two sows were fed the CON diet, whereas three gilts and three sows were fed ARG diets. Sows were fed a fixed amount of 6.0 kg/day, subdivided equally in four delivery times (0700, 1000, 1300 and 1600 h) for 21 days. At weaning, sows were slaughtered and mammary tissue samples and blood from the pudendal vein were collected. Data were analyzed considering each sow as an experimental unit. Differences were considered at P<0.05. L-arginine fed sows presented lower messenger RNA (mRNA) expression for prolactin receptor (P=0.002), angiopoietin1 (P=0.03) and receptor tyrosine kinase (P=0.01); higher mRNA expression for prostaglandin synthase 1 (P=0.01); a trend of decrease for glucocorticoid receptor (P=0.06) and IGF receptor 1 (P=0.07); and a trend (P=0.05) for an increased glutathione peroxidase mRNA expression. The angiopoietin2:angiopoietin1 mRNA ratio tended to increase (P=0.07) in ARG fed sows. L-arginine fed sows had greater (P=0.04) volumetric proportion of blood vessels and a trend of enhance (P=0.07) in the number of blood vessels per mm2. These findings show that 1.0% ARG supplementation to sows activates proliferative mechanisms, may improve mammary tissues' angiogenesis and tended to increase mRNA expression of genes that encode antioxidant enzymes in mammary gland of sows.

Chromium, CLA, and ractopamine for finishing pigs.

This study aimed to evaluate the effects of dietary chromium, CLA, and ractopamine on performance, carcass traits, and pork quality of finishing pigs slaughtered at 115 kg BW. Ninety-six crossbred barrows (initial BW = 70.21 ± 1.98 kg) were randomly assigned to 1 of 6 dietary treatments. There were 8 replicates per treatment (48 pens; 2 pigs/pen). A diet formulated according to the nutritional requirements was used as the control (CON). The other 5 diets were based on the CON and supplemented as follows: 0.4 mg/kg Cr yeast (CrY); 0.5% CLA; 0.4 mg/kg CrY and 0.5% CLA (CrY + CLA); 20 mg/kg ractopamine (RAC); 0.4 mg/kg CrY and 20 mg/kg RAC (CrY + RAC). Lysine levels on diets containing ractopamine were raised by 20% compared to CON to meet the greater requirements of pigs fed ractopamine. Pigs fed RAC and CrY + RAC were fed CON for the first 17 d, and then the respective diets for the last 28 d on trial. Data were analyzed in a model including the fixed effect of treatment (6 levels) and initial BW as a covariate for all characteristics, with the exception of carcass traits, in which final BW was used as a covariate. Least-squares means were separated using Tukey-Kramer's method. Differences were considered when probability values were lower than 0.05. Pigs fed RAC and CrY + RAC had the greatest ( < 0.001) final BW and ADG. Pigs fed CrY + RAC had greater ( < 0.001) G:F than pigs within the other groups, except for those fed RAC. Pigs fed CrY + RAC and RAC had similar G:F, both greater ( < 0.001) than pigs fed CON. Average daily feed intake was similar ( = 0.83) for all diets. Pigs fed CrY + RAC had greater LM area ( = 0.01) and carcass yield ( < 0.02) than pigs fed CON, CrY, CLA, and CrY + CLA. Loin muscle area and carcass yield of pigs fed RAC were not different from pigs fed the others diets. Pigs fed CON diets had greater BF ( = 0.02) than pigs fed CLA diet. Additives did not affect ( > 0.05) pork quality, except for color. No differences ( > 0.05) were observed for carcasses pH and temperature. The values for pigs fed RAC were greater ( = 0.01) than pigs fed other diets. Pigs fed RAC had lower ( < 0.01) values compared to pigs fed other experimental diets. Serum urea nitrogen concentration (SUN) was lower ( = 0.02) in pigs fed CrY + RAC than in pigs fed CON and RAC and similar to pigs fed the other feeding additives. In summary, it was demonstrated that, when combined, CrY and RAC increase LM area and carcass yield, and reduce SUN, suggesting that chromium could improve nutrient utilization by muscle cells in RAC-fed pigs. Additionally, the additives have no major effects on pork quality.

Technical evaluation of a tank-connected food waste disposer system for biogas production and nutrient recovery.

In this study, a tank-connected food waste disposer system with the objective to optimise biogas production and nutrient recovery from food waste in Malmö was evaluated. The project investigated the source-separation ratio of food waste through waste composition analyses, determined the potential biogas production in ground food waste, analysed the organic matter content and the limiting components in ground food waste and analysed outlet samples to calculate food waste losses from the separation tank. It can be concluded that the tank-connected food waste disposer system in Malmö can be used for energy recovery and optimisation of biogas production. The organic content of the collected waste is very high and contains a lot of energy rich fat and protein, and the methane potential is high. The results showed that approximately 38% of the food waste dry matter is collected in the tank. The remaining food waste is either found in residual waste (34% of the dry matter) or passes the tank and goes through the outlet to the sewer (28%). The relatively high dry matter content in the collected fraction (3-5% DM) indicates that the separation tank can thicken the waste substantially. The potential for nutrient recovery is rather limited considering the tank content. Only small fractions of the phosphorus (15%) and nitrogen (21%) are recyclable by the collected waste in the tank. The quality of the outlet indicates a satisfactory separation of particulate organic matter and fat. The organic content and nutrients, which are in dissolved form, cannot be retained in the tank and are rather led to the sewage via the outlet.

Carbon footprint of urban source separation for nutrient recovery.

Source separation systems for the management of domestic wastewater and food waste has been suggested as more sustainable sanitation systems for urban areas. The present study used an attributional life cycle assessment to investigate the carbon footprint and potential for nutrient recovery of two sanitation systems for a hypothetical urban area in Southern Sweden. The systems represented a typical Swedish conventional system and a possible source separation system with increased nutrient recovery. The assessment included the management chain from household collection, transport, treatment and final return of nutrients to agriculture or disposal of the residuals. The results for carbon footprint and nutrient recovery (phosphorus and nitrogen) concluded that the source separation system could increase nutrient recovery (0.30-0.38 kg P capita-1 year-1 and 3.10-3.28 kg N capita-1 year-1), while decreasing the carbon footprint (-24 to -58 kg CO2-eq. capita-1 year-1), compared to the conventional system. The nutrient recovery was increased by the use of struvite precipitation and ammonium stripping at the wastewater treatment plant. The carbon footprint decreased, mainly due to the increased biogas production, increased replacement of mineral fertilizer in agriculture and less emissions of nitrous oxide from wastewater treatment. In conclusion, the study showed that source separation systems could potentially be used to increase nutrient recovery from urban areas, while decreasing the climate impact.

Dispersively Detected Pauli Spin-Blockade in a Silicon Nanowire Field-Effect Transistor.

We report the dispersive readout of the spin state of a double quantum dot formed at the corner states of a silicon nanowire field-effect transistor. Two face-to-face top-gate electrodes allow us to independently tune the charge occupation of the quantum dot system down to the few-electron limit. We measure the charge stability of the double quantum dot in DC transport as well as dispersively via in situ gate-based radio frequency reflectometry, where one top-gate electrode is connected to a resonator. The latter removes the need for external charge sensors in quantum computing architectures and provides a compact way to readout the dispersive shift caused by changes in the quantum capacitance during inter-dot charge transitions. Here, we observe Pauli spin-blockade in the high-frequency response of the circuit at finite magnetic fields between singlet and triplet states. The blockade is lifted at higher magnetic fields when intra-dot triplet states become the ground state configuration. A line shape analysis of the dispersive phase shift reveals furthermore an intra-dot valley-orbit splitting Δvo of 145 µeV. Our results open up the possibility to operate compact complementary metal-oxide semiconductor (CMOS) technology as a singlet-triplet qubit and make split-gate silicon nanowire architectures an ideal candidate for the study of spin dynamics.

Atividade antimicrobiana dos extratos metanólicos da raiz, caule e folhas de Croton pulegioides Baill. (Zabelê) / Antimicrobial activity of methanol extracts of root, stem and leaves of Croton pulegioides Baill

O uso popular de plantas medicinais continua sendo de grande interesse para a população, principalmente em países em desenvolvimento, nos quais o acesso à medicina alopática ainda é muito restrito. Assim, além de sua importância na medicina tradicional, o conhecimento das plantas pode fornecer para a indústria farmacêutica, direta ou indiretamente, princípios ativos de interesse terapêutico. No presente trabalho foi avaliada a atividade antimicrobiana dos extratos metanólicos secos de Croton pulegioides Baill. obtidos a partir da raiz, do caule e das folhas nas concentrações de 25, 50 e 100mg/mL utilizando o método de difusão em Agar (técnica de poços) frente a cinco cepas Gram-positivas, três cepas de fungos e três cepas de bactérias Gram-negativas. Na execução do estudo foi utilizado o antibiótico Gentamicina (100µg/mL) no teste com bactérias, e Cetoconazol (300µg/mL) para as Candidas verificando-se, ao mesmo tempo, a ausência de atividade para o diluente DMSO 20% em água. Na observação dos resultados evidenciaram-se halos de inibição indicando atividade dos extratos metanólicos da raiz, caule e folhas, nas concentrações de 50 e 100mg/ml, frente Bacillus subtilis AM 04; dos extratos metanólicos da raiz e do caule, nas concentrações de 50 e 100mg/ml, frente Staphylococcus aureus AM 103 (ATCC 6538); e do extrato metanólico do caule, nas concentrações de 50 e 100mg/ml, frente S. epidermidis AM 235. Por outro lado, todos os extratos foram inativos nas concentrações avaliadas frente às bactérias Gram-negativas utilizadas no estudo (Pseudomonas aeruginosa AM 206, Escherichia coli AM 1050 e Klebsiella pneumoniae AM 410). Referente à atividade sobre fungos, os extratos metanólicos da raiz e do caule inibiram, nas três concentrações avaliadas, o crescimento de Candida tropicalis AM 1181 e C. albicans AM 1140, enquanto o extrato das folhas, inibiu o crescimento de C. tropicalis AM 1181 nas concentrações de 50 e 100mg/ml e de C. albicans AM 1140 apenas na concentração de 100mg/mL. Finalmente o extrato metanólico das folhas, na concentração de 100mg/mL, foi o único a inibir o crescimento de Candida krusei. Os resultados preliminares apresentados pelo presente trabalho sugeriram que a espécie Croton pulegioides Baill. apresentou resultados promissores quanto ao potencial antimicrobiano.

The employment of medicinal plants as a folk custom remains important to the present time, mainly in developing countries, where access to allopathic medicine is restricted. Besides their importance in traditional medicine, the knowledge on these plants can, directly or indirectly, provide information about the active ingredients involved, which may be of interest to the pharmaceutical industry. The present study evaluated the antimicrobial activity of dried methanolic extracts of Croton pulegioides Baill, extracted from its roots, stalk, and leaves, at the concentrations of 25, 50 and 100mg/ml. These were diffused in wells with an Agar medium, to which five strains of Gram-positive, three strains of fungi and three strains of Gram-negative bacteria had been added. For this study, the antibiotic Gentamicin (10µg/100µL) was used in tests with bacteria, and Ketoconazole (30µg/100µL), with Candidas. When DMSO diluted in 20% water was used, no activity was observed. The results produced evidence of inhibition halos, which indicates the activity of the methanolic extracts from the roots, stalk and leaves at the concentrations of 50 and 100 mg/ml for Bacillus subtilis AM 04; activity of the methanolic extracts from the roots and stalk at the concentrations of 50 and 100mg/ml for Staphylococcus aureus AM 103 (ATCC 6538); and activity of the methanolic extract from the stalk at the concentrations of 50 and 100mg/ml for Staphylococcus epidermidis AM 235. There was no activity in the concentrations studied for the Gram-negative bacteria (Pseudomonas aeruginosa AM 206, Escherichia coli AM 1050 and Klebsiella pneumoniae AM 410). With respect to fungal activity, the methanolic extracts from the roots and stalk inhibited Candida tropicalis AM 1181 and C. albicans AM 1140 at the three concentrations studied. The extract from the leaves inhibited the growth of C. tropicalis AM 1181 at the concentrations of 50 e 100mg/ml and C. albicans AM 1140 only at the concentration of 100mg/ml. Finally, the methanolic extract from the leaves, at the concentration of 100mg/ml, was the only one to inhibit the growth of Candida krusei. Preliminary results from this study suggest that the Croton pulegioides Baill showed promising results as a potential antimicrobial agent.

Effect of social ranks and gestation housing systems on oxidative stress status, reproductive performance, and immune status of sows.

Ninety-six multiparous sows were randomly assigned into 2 different gestation housing systems on d 35 of gestation: individual gestational crates (n = 24) or small groups with 3 sows in gestational pens (n = 24). Sows were classified into 4 treatments based on gestation housing systems and social ranks within each gestational pen: sows housed in individual gestational crates were in control treatment (CON), and sows destined to high, middle, or low social ranks within each pen were classified into high social rank treatment (HR), middle social rank treatment (MR), and low social rank treatment (LR). The social rank of sows within a pen was determined by their winning percentage during aggressive interactions observed for a 4-d period after mixing on d 35 of gestation. Plasma samples collected from each sow on d 35, 60, 90, and 109 of gestation and d 1 and 18 of lactation were used to determine concentrations of malondialdehyde (MDA), protein carbonyls, 8-hydroxy-deoxyguanosine (8-OHdG), IgG, and IgM. Sows in HR had higher (P < 0.05) body weight during gestation and lactation, smallest (P < 0.05) litter weight at birth, increased (P < 0.05) number of stillborn than sows in MR and LR, and tended to have decreased (P = 0.073, P = 0.064) number of born alive compared with sows in CON and LR. Sows in LR had lower farrowing rate compared with sows in MR. Plasma concentration of protein carbonyl in HR was higher (P < 0.05) than that in MR on d 3 of lactation. Plasma concentrations of 8-OHdG in LR was greater (P < 0.05) than that in HR on d 90 of gestation, d 3 and 18 of lactation, and greater (P < 0.05) than CON on d 18 of lactation. The reproductive performance of sows from all of the social ranks was related to their oxidative stress status during gestation and lactation. Collectively, the reproductive performance, oxidative stress status, and immune status did not differ between sows housed in gestational crates (CON) and pens (HR + MR + LR). Sows in CON and MR did not show inferior reproductive performance during gestation and lactation. Sows in HR and LR had increased oxidative damage during late gestation and lactation which could contribute to the reduced litter size and litter weight in HR and lower farrowing rate in LR.

Effect of heat stress and feeding phosphorus levels on pig electron transport chain gene expression.

The purpose of this study was to evaluate the effect of temperature and different levels of available phosphorus (aP) on the expression of nine genes encoding electron transport chain proteins in the Longissimus dorsi (LD) muscle of pigs. Two trials were carried out using 48 high-lean growth pigs from two different growth phases: from 15 to 30 kg (phase 1) and from 30 to 60 kg (phase 2). Pigs from growth phase 1 were fed with three different levels of dietary aP (0.107%, 0.321% or 0.535%) and submitted either to a thermoneutral (24°C and RH at 76%) or to a heat stress (34°C and RH at 70%) environment. Pigs from growth phase 2 were fed with three different levels of dietary aP (0.116%, 0.306% or 0.496%) and submitted either to a thermoneutral (22ºC and RH at 77%) or to a heat stress (32ºC and RH at 73%) environment. Heat stress decreased (P<0.001) average daily feed intake at both growth phases. At 24°C, pigs in phase 1 fed the 0.321% aP diet had greater average daily gain and feed conversion (P<0.05) than those fed the 0.107% or 0.535% while, at 34°C pigs fed the 0.535% aP had the best performance (P<0.05). Pigs from phase 2 fed the 0.306% aP had best performance in both thermal environments. Gene expression profile was analyzed by quantitative real-time polymerase chain reaction. Irrespective of growing phase, the expression of six genes was lower (P<0.05) at high temperature than at thermoneutrality. The lower expression of these genes under high temperatures evidences the effects of heat stress by decreasing oxidative metabolism, through adaptive physiological mechanisms in order to reduce heat production. In pigs from phase 1, six genes were differentially expressed across aP levels (P<0.05) in the thermoneutral and one gene in the heat stress. In pigs from phase 2, two genes were differentially expressed across aP levels (P<0.05) in both thermal environments. These data revealed strong evidence that phosphorus and thermal environments are key factors to regulate oxidative phosphorylation with direct implications on animal performance.

Níveis de fósforo disponível em dietas para suínos dos 15 aos 30kg / Available phosphorus levels in diets for pigs from 15 to 30kg

Avaliou-se a suplementação de dietas com fósforo disponível (Pd) para suínos selecionados para deposição de carne, utilizando-se 100 leitões com média de peso inicial de 15,03±0,33kg, distribuídos em delineamento de blocos ao acaso, com cinco tratamentos, cinco repetições e quatro animais por unidade experimental. Os tratamentos foram dieta basal sem suplementação de fosfato bicálcico e outras quatro dietas obtidas pela suplementação da dieta basal com fosfato bicálcico, resultando em cinco concentrações de Pd, 0,106; 0,221; 0,310; 0,406; e 0,493%. As porcentagens de Pd influenciaram o consumo diário de ração, que aumentou de forma linear. O ganho de peso diário aumentou e a conversão alimentar melhorou de forma quadrática até a suplementação máxima de 0,450 e 0,390% de Pd, respectivamente. Não houve efeito da suplementação das dietas sobre a resistência óssea. As porcentagens de Pd influenciaram de forma quadrática os teores de cálcio e de fósforo nos ossos, que aumentaram até a adição máxima de 0,388 e 0,369% de Pd, respectivamente. Não houve efeito da porcentagem de Pd sobre o teor de cinza óssea. Suínos dos 15 aos 30kg exigem maior concentração de Pd para máximo ganho de peso (0,450% ou 5,33g/dia) e melhor conversão alimentar (0,390% ou 4,52g/dia) em relação às recomendações atuais.

The supplementation of diets with available phosphorus (aP) for pigs selected for meat deposition was evaluated, using 100 commercial hybrid piglets, 50 castrated males and 50 females, with average initial weight of 15.03±0.33kg allotted in a randomized block design with five treatments, five replicates, and four pigs, 2 males and 2 females per experimental unit. The treatments were a basal diet and other four diets obtained through basal diet supplementation with dicalcium phosphate to obtain five aP concentrations, 0.106, 0.221, 0.310, 0,406, and 0.493%. The percentages of aP influenced daily feed intake, which increased linearly. Daily weight gain increased and feed conversion improved quadratically up to 0.450 and 0.390% maximum responses. There was no effect of diet supplementation on bone strength. The percentages of aP influenced the calcium and phosphorus contents in the bones, which increased quadratically up to 0.388 and 0.369% maximum responses, respectively. There was no effect of aP percentage in the bone ashe content. Pigs from 15 to 30kg require greater amount of aP in the diet for maximal weight gain (0.450% or 5.33g/d) and greatest feed conversion (0.390% or 4.52g/d) compared to current requirements.

Atividade antimicrobiana e sinérgica das frações das folhas de Schinopsis brasiliensis Engl. frente a clones multirresistentes de Staphylococcus aureus / Antimicrobial and synergic activity of fractions from the leaves of Schinopsis brasiliensis Engl. against Staphylococcus aureus multiresistant clones

No presente estudo objetivou-se avaliar a atividade antimicrobiana e sinérgica de 4 frações das folhas de Schinopsis brasiliensis Engl (F1', F2', F1" e F2") frente às cepas Staphylococcus aureus MRSA multirresistentes. Os métodos utilizados foram poços de difusão em ágar, concentração mínima inibitória (CMI) - diluição em ágar, e bioautografia. Nos resultados bioautográficos observou-se três halos de inibição relacionados, no mínimo, à quatro constituintes ativos; sendo dois deles isolados das folhas (galato de metila e ácido gálico). A F2" (200∝g/mL) apresentou halos de inibição de 16 e 19mm frente as cepas de S. aureus multirresistente e Klebsiella pneumoniae, e CMI 100∝g/mL, respectivamente. Quanto as análises das associações das frações F1" ou F2" (25 e 50∝g/mL) com a tetraciclina e oxacilina, mostraram ações aditiva e sinérgica para a F2" (50∝g/mL), embora não suficiente para que a CMI atingisse valores inferiores a 2 e 4∝g/mL, necessário para serem classificadas como cepas sensíveis a oxacilina e tetraciclina, respectivamente. "Assim, conclui-se que a F2" das folhas de S. brasiliensis apresentou potencial antimicrobiano frente às cepas de S. aureus MRSA multirresistentes e que as associações das frações com os antibióticos testados não apresentaram benefícios não justificando o uso concomitante.

The aim of this study was to evaluate the antimicrobial and synergic activity of 4 leaf fractions of Schinopsis brasiliensis Engl (F1', F2', F1" and F2") against multidrug-resistant Staphylococcus aureus strains. The used methods were agar well diffusion, minimum inhibitory concentration (MIC) - agar dilution, and bioautography. The bioautographic results showed three inhibition zones that corresponded to at least four active compounds, two of which (methyl gallate and gallic acid) have already been isolated from leaves. The F2" (200∝g/mL) fraction showed inhibition zones of 16 mm and 19 mm against S. aureus multidrug-resistant and Klebsiella pneumoniae strains and a MIC value of 100∝g/mL, respectively. The analyses of associations of fraction F1" or F2" (25 and 50∝g/mL) with tetracycline and oxacillin showed additive and synergistic action for F2" (50∝g/mL), although it was not enough to decrease the MIC values to less than 2 and 4∝g/mL, necessary to classify the strains as susceptible to oxacillin and tetracycline, respectively. Thus, it was concluded that F2" from the leaves of S. brasiliensis showed antimicrobial potential against multidrug-resistant MRSA strains, and the associations of the fractions with the tested antibiotics showed no benefits, not justifying their concomitant use.

Phenolic compounds and interaction between aminoglycosides and natural products of Lygodium venustum SW against multiresistant bacteria.

BACKGROUND: The aim of this work was to evaluate the interactions between aminoglycosides and the ethyl-acetate fraction of the fern Lygodium venustum SW (EAFLV) METHODS: The ethyl-acetate fraction was obtained from the ethanol extract of L. venustum and was assayed via the checkerboard method associated with aminoglycosides against two bacterial strains multiresistant to antibiotics. RESULTS: The antibiotic activity of all drugs, when associated with the ethyl-acetate fraction, was enhanced in an additive manner, except for the association between EAFLV and amikacin, which showed a synergistic interaction against the Escherichia coli strain. CONCLUSIONS: The results indicated that L. venustum can be a source of secondary metabolites to be used in association with antibiotics like aminoglycosides in antibiotic chemotherapy against resistant bacteria.

Phosphorus requirements for 60- to 100-kg pigs selected for high lean deposition under different thermal environments.

Two experiments were conducted to determine the requirement of available P (aP) of pigs selected for high lean deposition during summer (maximum and minimum temperatures of 29.8 ± 3.6 and 21.3 ± 1.1°C, respectively; Exp. 1) and winter (maximum and minimum temperatures of 24.7 ± 2.1 and 9.1 ± 1.6°C, respectively; Exp. 2). Pigs (66.5 ± 2.8 kg, Exp. 1; and 61.1 ± 0.6 kg, Exp. 2) were randomly allotted to 5 dietary treatments. Exp. 1 had 5 pens/treatment and Exp. 2 had 6 pens/treatment, and all pens had 2 pigs. Treatments were composed of a corn-soybean meal basal diet and 4 diets with additional dicalcium phosphate to obtain 5 aP concentrations (0.122, 0.187, 0.252, 0.317, and 0.382% in Exp. 1, and 0.135, 0.200, 0.265, 0.330, and 0.395% in Exp. 2). Pigs were allowed ad libitum access to their respective diets for 30 d. In Exp. 1, increasing aP improved ADFI and ADG (quadratic, P < 0.05), with maximum responses obtained at 0.226 and 0.256% of aP, respectively. Increasing aP improved (P < 0.05) G:F. A broken-line analysis indicated that G:F was maximized (P < 0.05) at 0.295% of aP or 9.04 g of aP/d. Increasing aP also increased (quadratic, P < 0.05) P and Ca (g/kg) in the metacarpals with maximum responses obtained at 0.314 and 0.272% of aP, respectively. The percentage of ash in the metacarpals continued to increase (linear, P < 0.05) with increasing aP. In Exp. 2, ADG and G:F improved (linear and quadratic, P < 0.05) as aP increased in the diet. A broken-line analysis indicated that G:F was maximized (P < 0.05) at 0.316% of aP or 10.58 g of aP per day. However, increasing aP had no effect on ADFI. Percentages of ash, P, and Ca in the metacarpals increased (linear, P < 0.05) with increasing aP. In conclusion, results of this experiment indicated that finishing pigs (60 to 100 kg) kept in a thermoneutral environment require 0.316% aP in the diet (10.58 g/d) to maximize G:F, but the requirement is only 0.295% aP (9.04 g/d) when pigs are under heat stress.