Inventário de algas bentônicas de praias e matacões rochosos da costa nordeste do Pará, Amazônia brasileira / Checklist of benthic algae from beaches and rocky outcrops on the northeast coast of Pará state, Brazilian Amazonia

Apresentamos um inventário com 23 táxons da flora ficológica bentônica em praias da costa nordeste do estado do Pará, na Amazônia brasileira, uma região raramente amostrada para algas. As coletas foram realizadas em substratos como matacões no município de Salinópolis, e em troncos, galhos e pneumatóforos de Laguncularia racemosa e substratos artificiais no município de Marapanim. Apesar das limitações da amostragem, nós registramos dez novas citações de algas marinhas e estuarinas bentônicas para a costa do estado do Pará: seis Chlorophyta (Bryopsis pennata, Cladophora coelothrix, C. conferta,Gayralia brasiliensis, Pseudorhizoclonium africanum e Ulva chaetomorphoides), duas Rhodophyta (Caloglossa confusa e Centroceras gasparrinii), uma Ochrophyta (Bachelotia antillarum) e uma Cyanophyta (Coleofasciculus chthonoplastes).(AU)

Role of systemic infection, cross contaminations and super-shedders in Salmonella carrier state in chicken.

Carriage of Salmonella is often associated with a high level of bacterial excretion and generally occurs after a short systemic infection. However, we do not know whether this systemic infection is required or whether the carrier-state corresponds to continuous reinfection or real persistence in caecal tissue. The use of a Salmonella Enteritidis bamB mutant demonstrated that a carrier-state could be obtained in chicken in the absence of systemic infection. The development of a new infection model in isolator showed that a marked decrease in animal reinfection and host-to-host transmission between chicks led to a heterogeneity of S. Enteritidis excretion and colonization contrary to what was observed in cages. This heterogeneity of infection was characterized by the presence of super-shedders, which constantly disseminated Salmonella to the low-shedder chicks, mainly through airborne movements of contaminated dust particles. The presence of super-shedders, in the absence of host-to-host transmission, demonstrated that constant reinfection was not required to induce a carrier-state. Finally, our results suggest that low-shedder chicks do not have a higher capability to destroy Salmonella but instead can block initial Salmonella colonization. This new paradigm opens new avenues to improve understanding of the carrier-state mechanisms and to define new strategies to control Salmonella infections.© 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

Relationships between digestive efficiency and metabolomic profiles of serum and intestinal contents in chickens.

The increasing cost of conventional feedstuffs has bolstered interest in genetic selection for digestive efficiency (DE), a component of feed efficiency, assessed by apparent metabolisable energy corrected to zero nitrogen retention (AMEn). However, its measurement is time-consuming and constraining, and its relationship with metabolic efficiency poorly understood. To simplify selection for this trait, we searched for indirect metabolic biomarkers through an analysis of the serum metabolome using nuclear magnetic resonance (1H NMR). A partial least squares (PLS) model including six amino acids and two derivatives from butyrate predicted 59% of AMEn variability. Moreover, to increase our knowledge of the molecular mechanisms controlling DE, we investigated 1H NMR metabolomes of ileal, caecal, and serum contents by fitting canonical sparse PLS. This analysis revealed strong associations between metabolites and DE. Models based on the ileal, caecal, and serum metabolome respectively explained 77%, 78%, and 74% of the variability of AMEn and its constitutive components (utilisation of starch, lipids, and nitrogen). In our conditions, the metabolites presenting the strongest associations with AMEn were proline in the serum, fumarate in the ileum and glucose in caeca. This study shows that serum metabolomics offers new opportunities to predict chicken DE.

The influence of a probiotic supplementation on memory in quail suggests a role of gut microbiota on cognitive abilities in birds.

The gut microbiota is involved in host behaviour and memory in mammals. Consequently, it may also influence emotional behaviour and memory in birds. Quail from two genetic lines with different fearfulness (LTI: long tonic immobility, n=37; STI: short tonic immobility, n=32) were either or not supplemented with a probiotic (Pediococcus acidilactici) from hatching. Emotional reactivity was measured in a tonic immobility test (d6 and 7 of age) and two open-field tests (d13-15; d22-24). Memory was measured in a test rewarded with mealworms, where quail had to remember the cups previously visited (d34-36). Quail endured a 5-days stress period from days 17 to 21 to help revealing the potentially beneficial effect of the probiotic. As expected, STI quail were less fearful compared to the LTI quail (p<0.05). Probiotic supplementation had no effect on most measures of emotional reactivity (p>0.05), except in the tonic immobility test where supplemented STI quail had lower immobility duration (p=0.0001). Regarding the memory test, the two lines had similar performances. Quail fed with probiotics made fewer errors (p=0.040). There was no significant correlation between traits of emotional reactivity and of memory. In conclusion, the supplementation with Pediococcus acidilactici as a probiotic, affected a specific trait of emotional reactivity in STI quail, and improved memory in both lines, whichstrengthens the idea that the influence of gut microbiota on the host behaviour and memory seen in mammals is shared by birds.

Detection of QTL controlling feed efficiency and excretion in chickens fed a wheat-based diet.

BACKGROUND: Improving feed efficiency is a major goal in poultry production in order to reduce production costs, increase the possibility of using alternative feedstuffs and decrease the volume of manure. However, in spite of their economic and environmental impact, very few quantitative trait loci (QTL) have been reported on these traits. Thus, we undertook the detection of QTL on 820 meat-type chickens from a F2 cross between D- and D+ lines that were divergently selected on low or high digestive efficiency at 3 weeks of age. Birds were measured for growth between 0 and 23 days, feed intake and feed conversion ratio between 9 and 23 days, breast and abdominal fat yields at 23 days, and the anatomy of their digestive tract (density, relative weight and length of the duodenum, jejunum, ileum, and ratio of proventriculus to gizzard weight) was examined. To evaluate excretion traits, fresh and dry weight, water content, pH, nitrogen to phosphorus ratio from 0 to 23 days, and pH of gizzard and jejunum contents at 23 days were measured. A set of 3379 single nucleotide polymorphisms distributed on 28 Gallus gallus (GGA) autosomes, the Z chromosome and one unassigned linkage group was used for QTL detection. RESULTS: Using the QTLMap software developed for linkage analyses by interval mapping, we detected 16 QTL for feed intake, 13 for feed efficiency, 49 for anatomy-related traits, seven for growth, six for body composition and ten for excretion. Nine of these QTL were genome-wide significant (four for feed intake on GGA1, one for feed efficiency on GGA2, and four for anatomy on GGA1, 2, 3 and 4). GGA16, 19, and 26 carried many QTL for different types of traits that co-localize at the same position. CONCLUSIONS: This study identified several QTL regions that are involved in the control of digestive efficiency in chicken. Further studies are needed to identify the genes that underlie these effects, and to validate these in other commercial populations and for different breeding environments.

Impact of Selection for Digestive Efficiency on Microbiota Composition in the Chicken.

OBJECTIVES: Feed efficiency and its digestive component, digestive efficiency, are key factors in the environmental impact and economic output of poultry production. The interaction between the host and intestinal microbiota has a crucial role in the determination of the ability of the bird to digest its food and to the birds' feed efficiency. We therefore investigated the phenotypic and genetic relationships between birds' efficiency and the composition of the cecal microbiota in a F2 cross between broiler lines divergently selected for their high or low digestive efficiency. METHODS: Analyses were performed on 144 birds with extreme feed efficiency values at 3 weeks, with feed conversion values of 1.41±0.05 and 2.02±0.04 in the efficient and non-efficient groups, respectively. The total numbers of Lactobacillus, L. salivarius, L. crispatus, C. coccoides, C. leptum and E. coli per gram of cecal content were measured. RESULTS: The two groups mainly differed in larger counts of Lactobacillus, L. salivarius and E. coli in less efficient birds. The equilibrium between bacterial groups was also affected, efficient birds showing higher C. leptum, C. coccoides and L. salivarius to E. coli ratios. The heritability of the composition of microbiota was also estimated and L. crispatus, C. leptum, and C. coccoides to E. coli ratios were moderately but significantly heritable (0.16 to 0.24). The coefficient of fecal digestive use of dry matter was genetically and positively correlated with L. crispatus, C. leptum, C. coccoides (0.50 to 0.76) and negatively with E. coli (-0.66). Lipid digestibility was negatively correlated with E. coli (-0.64), and AMEn positively correlated with C. coccoides and with the C. coccoides to Lactobacillus ratio (0.48 to 0.64). We also detected 14 Quantitative Trait Loci (QTL) for microbiota on the host genome, mostly on C. leptum and Lactobacillus. The QTL for C. leptum on GGA6 was close to genome-wide significance. This region mainly includes genes involved in anti-inflammatory responses and in the motility of the gastrointestinal tract.

Detection of QTL controlling digestive efficiency and anatomy of the digestive tract in chicken fed a wheat-based diet.

BACKGROUND: Improving digestive efficiency is a major goal in poultry production, to reduce production costs, make possible the use of alternative feedstuffs and decrease the volume of manure produced. Since measuring digestive efficiency is difficult, identifying molecular markers associated with genes controlling this trait would be a valuable tool for selection. Detection of QTL (quantitative trait loci) was undertaken on 820 meat-type chickens in a F2 cross between D- and D+ lines divergently selected on low or high AMEn (apparent metabolizable energy value of diet corrected to 0 nitrogen balance) measured at three weeks in animals fed a low-quality diet. Birds were measured for 13 traits characterizing digestive efficiency (AMEn, coefficients of digestive utilization of starch, lipids, proteins and dry matter (CDUS, CDUL, CDUP, CDUDM)), anatomy of the digestive tract (relative weights of the proventriculus, gizzard and intestine and proventriculus plus gizzard (RPW, RGW, RIW, RPGW), relative length and density of the intestine (RIL, ID), ratio of proventriculus and gizzard to intestine weight (PG/I); and body weight at 23 days of age. Animals were genotyped for 6000 SNPs (single nucleotide polymorphisms) distributed on 28 autosomes, the Z chromosome and one unassigned linkage group. RESULTS: Nine QTL for digestive efficiency traits, 11 QTL for anatomy-related traits and two QTL for body weight at 23 days of age were detected. On chromosome 20, two significant QTL at the genome level co-localized for CDUS and CDUDM, i.e. two traits that are highly correlated genetically. Moreover, on chromosome 16, chromosome-wide QTL for AMEn, CDUS, CDUDM and CDUP, on chromosomes 23 and 26, chromosome-wide QTL for CDUS, on chromosomes 16 and 26, co-localized QTL for digestive efficiency and the ratio of intestine length to body weight and on chromosome 27 a chromosome-wide QTL for CDUDM were identified. CONCLUSIONS: This study identified several regions of the chicken genome involved in the control of digestive efficiency. Further studies are necessary to identify the underlying genes and to validate these in commercial populations and breeding environments.

Heterogeneity of persistence of Salmonella enterica serotype Senftenberg strains could explain the emergence of this serotype in poultry flocks.

Salmonella enterica serotype Senftenberg (S. Senftenberg) has recently become more frequent in poultry flocks. Moreover some strains have been implicated in severe clinical cases. To explain the causes of this emergence in farm animals, 134 S. Senftenberg isolates from hatcheries, poultry farms and human clinical cases were analyzed. Persistent and non-persistent strains were identified in chicks. The non-persistent strains disappeared from ceca a few weeks post inoculation. This lack of persistence could be related to the disappearance of this serotype from poultry farms in the past. In contrast, persistent S. Senftenberg strains induced an intestinal asymptomatic carrier state in chicks similar to S. Enteritidis, but a weaker systemic infection than S. Enteritidis in chicks and mice. An in vitro analysis showed that the low infectivity of S. Senftenberg is in part related to its low capacity to invade enterocytes and thus to translocate the intestinal barrier. The higher capacity of persistent than non-persistent strains to colonize and persist in the ceca of chickens could explain the increased persistence of S. Senftenberg in poultry flocks. This trait might thus present a human health risk as these bacteria could be present in animals before slaughter and during food processing.

Evaluation of PCR and DNA sequencing for direct detection of Clostridium perfringens in the intestinal tract of broilers.

The aim of this investigation was to determine the presence of the opportunistic pathogen Clostridium perfringens by PCR and DNA sequencing, without previous cultivation. This methodology was then used to investigate how C. perfringens was affected by different preventive measures, such as ionophores and feed additives, for necrotic enteritis in broilers chickens. DNA was extracted from the intestinal content or intestinal tissue by DNA extraction kits. Detection limits for 16S rRNA, alpha-toxin, and cpb2 PCR gene targets were approximately 1 x 10(3), 5 x 10(4), and 1 x 10(6) cells per g of intestinal content or tissue, respectively, as determined with samples spiked with C. perfringens. The method was evaluated with samples from single conventional broilers or from pools of six birds of experimentally reared broilers. Conventional chickens, raised with salinomycin in their feed, showed reduced numbers of C. perfringens-positive samples (P < 0.05) for all three PCR tests. With respect to cpb2, a tendency to detect more samples as positive for C. perfringens was observed with increasing age. The addition of sodium butyrate and lactic acid in the feed for experimental birds had a minor effect (P < 0.10) on positive samples, as detected with the 16S rRNA PCR. For experimental birds fed whole wheat, only three out of six pools of six birds allowed detection of C. perfringens by the 16S rRNA PCR, compared to five for the untreated controls or the Avilamycin- or prebiotic-treated birds. All 16S rRNA partial gene sequences obtained were identical and were 99.5% similar to the rrnB gene of the type strain of C. perfringens. Two types of the partial cpb2 gene sequence were detected with a similarity of 93%. One type was translated into protein, whereas a stop codon was found in the other type. Both types were located in the "atypical" phylogenetic group of the cpb2 gene sequences. The PCR test, based on extraction of DNA from intestinal content, provided rapid screening of poultry for C. perfringens without the need to have access to facilities in order to immediately cultivate and identify bacteria at the location of sampling. Further work is suggested to determine the relationship between the degree of necrotic enteritis, the actual level of C. perfringens in the animal, and the detection achieved by PCR.