Dietary administration of a commercial mixed-species probiotic improves growth performance and modulates the intestinal immunity of tilapia, Oreochromis niloticus.

The growth performance, immunological status, intestinal morphology and microbiology of tilapia, Oreochromis niloticus, were investigated after dietary administration of the commercial probiotic AquaStar(®) Growout. Tilapia (29.02 ± 0.33 g) were split into five treatments; control (CON), 1.5 g kg(-1) probiotic (PRO-1.5), 3 g kg(-1) probiotic (PRO-3), pulsed probiotic feeding (PRO-PULSE) or an initial probiotic feed followed by control feeding (PRO-INI). After six weeks of experimental feeding, fish fed PRO-3 displayed significantly higher final weight, weight gain and SGR compared to the CON or PRO-INI treatments. Supplementation of the probiotic at this dose induced an up-regulation of intestinal caspase-3, PCNA and HSP70 mRNA levels compared to the CON fed fish. Immuno-modulatory pathways were also affected; significantly higher expression of TLR2, pro-inflammatory genes TNFα and IL-1β, and anti-inflammatory genes IL-10 and TGFβ suggest that the probiotic may potentiate a higher state of mucosal tolerance and immuno-readiness. Histological appraisal revealed significantly higher numbers of intraepithelial leucocytes in the intestine of PRO-3 fed fish compared with treatments CON, PRO-PULSE and PRO-INI but not PRO-1.5. Additionally, fish receiving PRO-3 had a significantly higher abundance of goblet cells in their mid-intestine when compared with fish from all other treatments. Together, these data suggest that continuous provision of AquaStar(®) Growout at 3 g kg(-1) can improve tilapia growth and elevate the intestinal immunological status of the host

Probiotic Pediococcus acidilactici modulates both localised intestinal- and peripheral-immunity in tilapia (Oreochromis niloticus).

The application of probiotics in aquaculture has received concerted research efforts but the localised intestinal immunological response of fish to probiotic bacteria is poorly understood. Therefore, a study was conducted to evaluate the probiotic effect of Pediococcus acidilactici on Nile tilapia (Oreochromis niloticus) with specific emphasis on intestinal health and probiotic levels as well as system level responses such as growth performance, feed utilization and haemato-immunological parameters under non-challenged conditions. Fish (9.19 ± 0.04 g) were fed either a control diet or a P. acidilactici supplemented diet (at 2.81 × 10(6) CFU g(-)(1)) for six weeks. At the end of the study the probiotic was observed to populate the intestine, accounting for ca. 3% (1.59 × 10(5) CFU g(-)(1)) of the cultivable intestinal bacterial load. Real-time PCR indicated that the probiotic treatment may potentiate the immune-responsiveness of the intestine as up-regulation of the gene expression of the pro-inflammatory cytokine TNFα was observed in the probiotic fed fish (P 0.05)

Bulk and amino acid isotope analyses of hair detail adult diets and infant feeding practices among pre- and post-maize populations of the northern Chilean coast of the Atacama Desert

This study investigates diet heterogeneity among Chinchorro and Inca adults and subadults living on the northern Chilean coast of the Atacama Desert before and after the introduction of maize cultivation. This is achieved by amino acid carbon isotope analysis and bulk carbon, nitrogen, and sulphur isotope analysis of 1-cm sequential segments of scalp hair from human remains deposited at the funerary sites of Morro 1 and 1–6 (Archaic Period) and Camarones 9 (Late Period). Results show that Chinchorro adults relied predominantly on marine resources and partially on wild plants. Inter-individual variability in diet was limited, indicating food redistribution between sexes. Childhood and adolescent diets were comparable to those of the adults. Partial breastfeeding was continued up to the age of 2–3 yrs. Subsequently, Inca adults relied on a combination of marine resources and maize. Intra- and inter-individual variability in diet was limited suggesting existence of a centralised system of food procurement and redistribution. Childhood and juvenile diets were comparable to those of the adults, except for two malnourished children being raised on maize. Amino acid δ13C analysis of hair keratin is proposed as a potential tool for reconstructing the nutritional status of an infant without population-specific maternal isotope baseline

Modulation of the intestinal microbiota and morphology of tilapia, Oreochromis niloticus, following the application of a multi-species probiotic.

The intestinal microbiota and morphology of tilapia (Oreochromis niloticus) were investigated after the application of a multi-species probiotic containing Lactobacillus reuteri, Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici (AquaStar(®) Growout). Tilapia (55.03 ± 0.44 g) were fed either a control diet or a probiotic diet (control diet supplemented with AquaStar(®) Growout at 5 g kg(-1)). After four and eight weeks, culture-dependent analysis showed higher levels of lactic acid bacteria (LAB), enterococci and Bacillus spp. in the mucosa and digesta of fish fed AquaStar(®) Growout. At week four, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) revealed a higher similarity within the probiotic fed replicates than replicates of the control group; after eight weeks, the compositional dissimilarity of the microbiome profiles between the groups was greater than the dissimilarities within each group (P 99 % of reads). Bacillus, Cetobacterium and Mycobacterium were the dominant genera in the digesta of control fish whereas Bacillus, Enterococcus and Pediococcus were the largest constituents in probiotic-fed fish. The addition of AquaStar(®) Growout to tilapia diets led to increased populations of intraepithelial leucocytes, a higher absorptive surface area index and higher microvilli density in the intestine. These data suggest that AquaStar(®) Growout can modulate both the intestinal microbiota and morphology of tilapia

POPULATION GENETICS. Genomic evidence for the Pleistocene and recent population history of Native Americans.

How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we found that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (ka) and after no more than an 8000-year isolation period in Beringia. After their arrival to the Americas, ancestral Native Americans diversified into two basal genetic branches around 13 ka, one that is now dispersed across North and South America and the other restricted to North America. Subsequent gene flow resulted in some Native Americans sharing ancestry with present-day East Asians (including Siberians) and, more distantly, Australo-Melanesians. Putative "Paleoamerican" relict populations, including the historical Mexican Pericúes and South American Fuego-Patagonians, are not directly related to modern Australo-Melanesians as suggested by the Paleoamerican Model