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Biogas production from animal waste is an economically viable way to reduce environmental pollution and produce valuable products, i.e., methane and a nutrient-rich organic waste product. An anaerobic digestion reactor for biogas production from pig waste was sampled at the entrance, middle (digestion chamber), and exit of a digester, while the bacterial and archaeal community structure was studied by 16S rRNA gene metagenomics. The number of bacterial operational taxonomic units (OTU)-97% was 3-7 times larger than that of archaeal ones. Bacteria and Archaea found in feces of animals (e.g., Clostridiaceae, Lachnospiraceae, Ruminococcaceae, Methanosarcina, Methanolobus, Methanosaeta, and Methanospirillum) dominated the entrance of the digester. The digestion chamber was dominated by anaerobic sugar-fermenting OP9 bacteria and the syntrophic bacteria Candidatus Cloacamonas (Waste Water of Evry 1; WWE1). The methanogens dominant in the digestion chamber were the acetoclastic Methanosaeta and the hydrogenothrophic Methanoculleus and Methanospirillum. Similar bacterial and archaeal groups that dominated in the middle of the digestion chamber were found in the waste that left the digester. Predicted functions associated with degradation of xenobiotic compounds were significantly different between the sampling locations. The microbial community found in an anaerobic digestion reactor loaded with pig manure contained microorganisms with biochemical capacities related to the 4 phases of methane production.

The factors influencing half‐pearl (mabe) production in the red abalone Haliotis rufescens were investigated, as a strategy to optimize the technology for the development of a pearling industry in Chile. The effects of abalone size (small, large), implant position (dorsal, central, ventral and their combinations), and number of nuclei (one, two, three) were analysed on the quantity, thickness of the nacre layer and quality (shape, colour, lustre, defects) of the mabe produced. The size of abalone did not exert a clear influence on the quantity and quality of mabe, but the position on the shell (firstly) and number of nuclei (secondly) did. More mabe, with thicker nacre, brighter lustre and fewer defects occurred in small or large abalone implanted with only one nucleus on dorsal position. In contrast, small and large abalone implanted in the ventral position formed less mabe, with thinner nacre, poor lustre and more defects. This likely occurs because mantle tissue folds at the ventral position and does not always cover the nucleus, leaving it partially or totally exposed. Most of the pearls were categories AA in small abalone and A in large abalone; only three AAA gems were produced in large abalone with one nucleus on dorsal position or with three nuclei (DCV). Based on these results, we recommend implanting abalone at 60–100 mm shell length, with only one nucleus on the dorsal position.

Objective. To study the effect of homeopathic medicines on growth, survival and gastrointestinal (GIT) microbiota of Catarina scallop Argopecten ventricosus. Materials and methods. Five homeopathic treatments (T1) ViP-ViA 1D, (T2) ViP-ViA 7C, (T3) AcF-MsS 1D, (T4) PhA-SiT 7C, (T5) ViT 31C and three controls: (C1) diluted ethanol 1:99, (C2) diluted/succussed ethanol 1C and (C3) distilled water were evaluated (21 days) in triplicate. Microbiota was analysed by sequencing the V3-V5 region of the 16S rRNA genes. Results. The best growth in shell-length corresponded to T1 (117 µm d-1) and T2 (108 µm d-1) and the highest survival (P ≤ 0.05) to T3 and T5, stating T3 as the best HOM-treatment. A clear separation was found in rarefaction curves of HOM-treated against un-treated control scallops. Significant differences (P ≤ 0.05) were found for Phyla (Proteobacteria> Actinobacteria> Firmicutes> Bacterloidetes>Chloroflexi and for Genera: Symbiobacterium> Microbacterium> Methylobacillus> Bacillus> Paenibacillus> Burkholderia> Nostoc> Methylobacterium> Leucobacter). The genus Symbiobacterium was dominant in the HOM-treatment T5 (Vidatox®), finding significant differences (P ≤ 0.05) with respect to all treatments. At species level, Microbacterium maritypicum (Actinobacteria) showed a greater relative abundance (P ≤ 0.05) in T1 and T3 and Symbiobacterium toebii (Firmicutes) was also significantly higher (P ≤ 0.05) in abundance in T5 and T2, both against initial T0. Conclusions. This study showed for the first time, the composition of the GIT microbiota in Catarina scallop A. ventricosus and focused on the potential applicability of homeopathic medicines to improve overall performance and modulate the GIT microbiota of the species.