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A negative energy balance (NEB) is detrimental to reproduction in animals. A suggested link between NEB and reproductive failure is the gastrointestinal hormone ghrelin, because of the association between ghrelin and the hypothalamo-pituitary-gonadal axis. The [D-Lys3]-Growth Hormone Releasing Peptide-6 ([D-Lys3]-GHRP-6) is a ghrelin antagonist that acts on ghrelin receptors (GHS-R1). The objective of this study was to evaluate the effect of [D-Lys3]-GHRP-6 on reproduction variables in feed restricted ewes. Two experiments were conducted. Experiment I was conducted for 30 days; and Experiment II for 13 days. In both experiments the ewes (n = 18) were randomly assigned to: Control (CO): fed to meet maintenance requirements; Feed restriction (FR): 80% of maintenance restriction; or Ghrelin antagonist (GA): feed restricted and daily subcutaneous of 7.5μg/kg of [D-Lys3]-GHRP-6. Plasma was collected to measure hormones and metabolite concentration. In Experiment II, the hypothalamus and ovaries were collected on day 13. In both Experiments, sheep allocated to the FR and GA treatments decreased their body weight compared with sheep in the CO group (P < 0.06); progesterone however, did not differ between treatments (P > 0.10). Experiment I: Plasma ghrelin concentration was greater (P < 0.01) in FR and GA compared with CO ewes. Plasma non-esterified fatty acids concentration was greater (P < 0.01) in GA and FR than CO. Experiment II: Kisspeptin1-Receptor (Kiss1-R) mRNA expression was greater in FR (P < 0.01) and tended to be greater in GA (P = 0.10) compared with CO ewes. The neuro peptide-Y (NPY) mRNA expression was greater (P = 0.03) in FR than CO; and tended to be greater (P = 0.06) compared with GA ewes. Growth hormone releasing hormone (GhRH) mRNA expression was greater in GA (P = 0.04) and tended to be greater in FR (P = 0.07) compared with CO ewes. Feed restriction increased GhRH, NPY, and Kiss-R mRNA expression in hypothalamus without affecting reproductive variables.Ghrelin antagonist may prevent an increase inNPY expression in ewes.

The effect of a pine invasion on the fuel characteristics was studied to predict fire behaviour and hypothesize potential changes on fire regime. Subalpine Andean forests, fire-prone environments, in the Malalcahuello Reserve in south-central Chile were invaded by the non-native Pinus contorta affecting the native endangered trees Araucaria araucana and Nothofagus antarctica communities. Several fuel components were evaluated by studying different variables, such as fuel load, vertical and horizontal continuity, and flammability of native and invasive tree species. The survey was conducted in five stand conditions: A. araucana and N. antarctica stands, each with and without invasion of P. contorta, and stands with only P. contorta (invasion source). The invasion of P. contorta increased the vertical fuel continuity in the Araucaria forest. The flammability analysis showed that P. contorta is a species highly flammable in comparison to the native trees. The invasion of P. contorta in the Malalcahuello Reserve is under progression and if the process of invasion continues the effects on fuel characteristics will increase. These results suggest that wildfires will be more intense and severe, and that the type of fires of the Malalcahuello Reserve will change from a mixed fire regime to a crown fire regime. These changes will affect plant regeneration, and a positive feedback that favours the P. contorta invasion could emerge. Long-term studies to understand the effect of invasive woody plants on the fire regime are essential for the control of these invasions, especially for the conservation of biodiversity and ecosystem processes in the Araucaria–Nothofagus ecosystems is the Chilean and Argentinean Patagonia.

Amide-linked conjugates of indole-3-acetic acid (IAA) have been identified in most plant species. They function in storage, inactivation or inhibition of the growth regulator auxin. We investigated how the major known endogenous amide-linked IAA conjugates with auxin-like activity act in auxin signaling and what role ILR1-like proteins play in this process in Arabidopsis. We used a genetically encoded auxin sensor to show that IAA-Leu, IAA-Ala and IAA-Phe act through the TIR1-dependent signaling pathway. Furthermore, by using the sensor as a free IAA reporter, we followed conjugate hydrolysis mediated by ILR1, ILL2 and IAR3 in plant cells and correlated the activity of the hydrolases with a modulation of auxin response. The conjugate preferences that we observed are in agreement with available in vitro data for ILR1. Moreover, we identified IAA-Leu as an additional substrate for IAR3 and showed that ILL2 has a more moderate kinetic performance than observed in vitro . Finally, we proved that IAR3, ILL2 and ILR1 reside in the endoplasmic reticulum, indicating that in this compartment the hydrolases regulate the rates of amido-IAA hydrolysis which results in activation of auxin signaling.

Pinus contorta is considered one of the most invasive tree species worldwide, generating significant impacts on biodiversity and ecosystems. In several Patagonian ecosystems in southern Chile, it has escaped from plantations established mainly in the 1970s, and is now invading both forests and treeless environments. In this study, we evaluated the impact of the invasion of P. contorta on microenvironmental conditions in Araucaria araucana forest and Patagonian steppe ecosystems, and assessed how these changes related to the richness and abundance of native and non-native plant species. In each ecosystem, 24 plots of 100 m2 were established along a gradient of P. contorta biomass, where 18 environmental variables and the composition of native and non-native vegetation were measured at a local scale. Our results indicated that increased pine biomass was associated with differences in microclimatic conditions (soil and air temperature, photosynthetically active radiation (PAR), and soil moisture) and soil properties (potassium, nitrate, pH, and litter accumulation). These changes were ecosystem dependent, however, as well as associated with the level of invasion. Finally, the reduction in the richness and abundance of native plants was associated with the changes in soil properties (accumulation of leaf litter, pH, and organic matter) as well as in the microclimate (minimum air temperature, PAR) generated by the invasion of P. contorta. Overall, our results confirm that the invasion of P. contorta impacts microenvironmental conditions (i.e., canopy cover, litter accumulation, minimum air temperature, and maximum soil temperature) and reduces native plant diversity. For future restoration plans, more emphasis should be given to how environmental changes can influence the recovery of invaded ecosystems even after the removal of the living pine biomass (i.e., legacy of the invasion).

Fil: Carranza Martin, Ana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria \"Ing. Fernando Noel Dulout\". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina

The effect of bacterial additives on immune response, intestinal microbiota, and survival of the white shrimp Litopenaeus vannamei was evaluated. Bacillus licheniformis BCR 4–3 and Vibrio parahaemolyticus IPNGS16 cultures were spray-dried. Inulin, probiotics, and postbiotics of Bacillus (SPB) and postbiotics of Vibrio (PVp) were added to the commercial feed. An experiment with three treatments in triplicate was performed during 19 days. The growth was not affected by the additives but survival of animals was significantly higher as compared to control group. The expression of SOD, crustin, and penaeidin4 in PVp-treated animals was significantly higher compared to the control but lysozyme expression did not change. The phyla, families, and genera that predominated in the white shrimp intestine were Proteobacteria, Bacteroidetes, Rhodobacteraceae, Vibrionaceae, Pseudoalteromonadaceae, Vibrio , Ruegeria , and Phaeobacter . The Vibrio genus decreased significantly in SPB and PVp treatments, compared to the control. The control, SPB, and PVp shared 294 OTUs. No changes were observed in the alpha and beta diversity. The metabolic activity of Vibrio and Roseobacter was higher in the control compared to SPB and PVp, whereas for Phaeobacter and Ruegeria , it decreased. Feed additives increase survival and modulated the immune response and gut microbiota of the white shrimp, so they can be used in commercial farms to increase production.

Shrimp is one of the most important aquaculture industries. Therefore, we determined the effect of nitrifying-probiotic bacteria on water quality, growth, survival, immune response, and intestinal microbiota of Litopenaeus vannamei cultured without water exchange. In vitro, only Bacillus licheniformis used total ammonia nitrogen (TAN), nitrites, and nitrates since nitrogen bubbles were produced. TAN decreased significantly in the treatments with B. licheniformis and Pediococcus pentosaceus and Leuconostoc mesenteroides, but no differences were observed in nitrites. Nitrates were significantly higher in the treatments with bacteria. The final weight was higher only with bacilli and bacilli and LAB treatments. The survival of shrimp in the bacterial treatments increased significantly, and superoxide anion increased significantly only in lactic acid bacteria (LAB) treatment. The activity of phenoloxidase decreased significantly in the treatments with bacteria compared to the control. Shrimp treated with bacilli in the water showed lower species richness. The gut bacterial community after treatments was significantly different from that of the control. Linoleic acid metabolism was positively correlated with final weight and superoxide anion, whereas quorum sensing was correlated with survival. Thus, bacilli and LAB in the water of hyperintensive culture systems act as heterotrophic nitrifers, modulate the intestinal microbiota and immune response, and improve the growth and survival of shrimp. This is the first report on P. pentosaceus and L. mesenteroides identified as nitrifying bacteria.

Abstract The objective of this study was to evaluate the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation to ewes during late gestation on finishing lamb liver and adipose tissue fatty acid (FA) profile and gene expression. Lambs born from ewes supplemented with Ca salts of EPA + DHA, or palm FA distillate (PFAD) high in palmitic and oleic acid at 0.39% DM during the last 50 d of gestation were used. Lambs were weaned at 61 d of age and adapted to a high concentrate diet for 1.5 mo. After adaptation, 74 lambs (28 pens) were blocked by sex and BW and used in a 2 × 2 factorial arrangement of treatments using the factors of dam supplementation (DS) and lamb supplementation (LS) of Ca salts of EPA + DHA or PFAD at 1.48% DM. Lambs were slaughtered after 42 d and liver and adipose tissue collected for FA and gene expression analysis. Liver concentrations of EPA and DHA were greater (P < 0.01) with LS of EPA + DHA vs. PFAD during the finishing period. In adipose tissue, a lamb × dam interaction was observed for EPA (P = 0.02) and DHA (P = 0.04); LS of EPA + DHA increased EPA and DHA, but the increase was greatest in lambs born from ewes supplemented with PFAD. No lamb × dam treatment interactions were observed for gene expression in liver tissue (P > 0.10). Hepatic mRNA abundance of hormone-sensitive lipase (HSL; P = 0.01) was greater in lambs born from EPA + DHA ewes vs. lambs from PFAD ewes. mRNA expression of stearoyl-CoA desaturase (P < 0.01), fatty acid synthase (P = 0.01), Δ5-desaturase (P < 0.01), and Δ6-desaturase (P < 0.01) were decreased in liver of EPA + DHA lambs. A significant lamb × dam diet interaction was observed for elongation of very long chain fatty acid 2 in adipose tissue (P = 0.01); lambs supplemented with the same FA as their dams had lower expression. Expression of HSL tended (P = 0.08) to be decreased in adipose of EPA + DHA lambs born from EPA + DHA ewes. The changes in mRNA expression suggest that lipogenesis decreased, and lipolysis increased in lamb liver with EPA + DHA vs. PFAD supplementation during the finishing period. In adipose tissue, changes suggest that lipogenesis decreased in lambs born from EPA + DHA supplemented dams and supplemented with EPA + DHA during the finishing period. In addition, these results suggest an interaction between supplementation of FA to dams during late gestation on lamb response of adipose tissue, but not liver, to FA supplementation during the finishing period.

This study investigated the effect of probiotics on growth performance, survival, and gut microbiota of Penaeus vannamei challenged with Vibrio parahaemolyticus IPNGS16. Shrimp were exposed to Bacillus thuringiensis IPNGSM1 and Candida parapsilosis Lt6 (BY, bacilli, 3×106 CFU L-1; yeast, 3×106 CFU L-1; yeast, 3 g kg-1 feed) every fourth day for 30 days. On day 26, weight was determined, and samples for gut microbiota analysis were taken. Vibrio infection was performed on day 27. The software Shaman and MicrobiomeAnalyst were used to analyze the microbial sequences obtained from the Illumina platform. Additives did not affect growth, but survival significantly increased in shrimp treated with BY and challenged with V. parahaemolyticus. Predominant bacteria in shrimp gut belonged to Proteobacteria, Bacteroidetes, Vibrio, and Ruegeria. The bacterial community's diversity and composition did not change between treatment and control. In the treatment with BY, Vibrio showed decreased abundance, metabolism, and functional importance and showed negative interactions against Ruegeria, Pseudoalteromonas, Bacillus, and Roseobacter. Microbial additives increased survival in white shrimp but positively affected bacteria with probiotic potential and Vibrio negatively.

The prawn Macrobrachium tenellum is a species with high expectations for farming. However, like all cultivated species, it is exposed to bacterial infections caused by captivity and cultivation conditions. In this sense, probiotics in aquaculture have been used as an alternative against the excessive use of antibiotics in farming, thus preventing diseases. In the present work, 106 strains with probiotic potential were isolated, of which 77 are bacilli, and 29 are lactic acid bacteria (LAB) [(intestine (43), stomach (42) and hepatopancreas (21)] from the shrimp M. tenellum collected from a freshwater environment in Guasave, Sinaloa. Biochemical characterization of the isolated bacterial strains and molecular identification of the 16S ribosomal gene were performed. According to the hemolytic activity, the isolates MT4H2 (bacilli) and MT1E2 (LAB) showed gamma hemolysis (Ɣ), and the LAB strain presented catalase-negative. Both were Gram (+). They presented high hydrophobicity values (99.93 and 73.21%) in autoaggregation (90%) and coaggregation (99%). Regarding biofilm formation, both presented moderate capacity. On salinity tolerance, they grew in concentrations of 0 to 9% NaCl and a pH tolerance within a range of 5 to 9. Regarding enzyme activity, they exhibited activity in both proteases and lipases. Both presented resistance to some of the antibiotics tested. Only the strain of bacillus exhibited antagonistic activity against Vibrio parahaemolyticus. They were identified as Pontibacillus sp. and Pediococcus pentosaceus at a molecular level.