Supplementation of chestnut tannins in diets can improve meat quality and antioxidative capability in Hu lambs

Chestnut tannins (CNT), as a source of hydrolyzable tannins, positively affect the antioxidant status of livestock. In the current study, 90 male Hu lambs were used to investigate the effect of dietary CNT intake on growth performance, nutrient digestibility, meat quality and oxidative stability, rumen microbial, and the transcriptomes of muscle and liver. A completely randomized design with three CNT intake levels (0, 0.3%, and 0.6%) was used. Rumen microbial and nutrient digestibility were not significantly altered by CNT intake. Diets with 0.3% CNT intake significantly reduced the shear force, yellowness at 24 h, and C20:2 polyunsaturated fatty acids of lamb meat and malondialdehyde in serum and longissimus thoracis (LT) muscle. Meanwhile, the 0.3% CNT diet significantly increased average daily gain during the 1- 21 days and 64- 90 days, dry matter intake during the 1- 21 days, the slaughter weight, and liver index of lambs. The 0.3% CNT diet significantly increased C26:0 saturated fatty acids, total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase in LT muscle. The meat shelf life of 0.3% CNT and 0.6% CNT groups was prolonged by 8.7 h and 5.4 h, respectively. Transcriptomic analysis revealed that CNT supplementation can induce the expression of antioxidant enzyme gene (CAT, SOD1), and the differentially expressed genes were mainly involved in antioxidant activity, transferase activity, and adenosine triphosphate binding. These results suggest that 0.3% CNT intake can relieve the oxidative stress of lambs, and improve the stability of meat color and meat tenderness, due to the enhanced antioxidative capacity.

Tomato Plant Microbiota under Conventional and Organic Fertilization Regimes in a Soilless Culture System

Tomato is the main vegetable cultivated under soilless culture systems (SCSs); production of organic tomato under SCSs has increased due to consumer demands for healthier and environmentally friendly vegetables. However, organic tomato production under SCSs has been associated with low crop performance and fruit quality defects. These agricultural deficiencies could be linked to alterations in tomato plant microbiota; nonetheless, this issue has not been sufficiently addressed. Thus, the main goal of the present study was to characterize the rhizosphere and phyllosphere of tomato plants cultivated under conventional and organic SCSs. To accomplish this goal, tomato plants grown in commercial greenhouses under conventional or organic SCSs were tested at 8, 26, and 44 weeks after seedling transplantation. Substrate (n = 24), root (n = 24), and fruit (n = 24) composite samples were subjected to DNA extraction and high-throughput 16S rRNA gene sequencing. The present study revealed that the tomato core microbiota was predominantly constituted by Proteobacteria, Actinobacteria, and Firmicutes. Remarkably, six bacterial families, Bacillaceae, Microbacteriaceae, Nocardioidaceae, Pseudomonadaceae, Rhodobacteraceae, and Sphingomonadaceae, were shared among all substrate, rhizosphere, and fruit samples. Importantly, it was shown that plants under organic SCSs undergo a dysbiosis characterized by significant changes in the relative abundance of Bradyrhizobiaceae, Caulobacteraceae, Chitinophagaceae, Enterobacteriaceae, Erythrobacteraceae, Flavobacteriaceae, Nocardioidaceae, Rhodobacteraceae, and Streptomycetaceae. These results suggest that microbial alterations in substrates, roots, and fruits could be potential factors in contributing to the crop performance and fruit quality deficiencies observed in organic SCSs.

Do methanotrophs drive phosphorus mineralization in soil ecosystem?

Experiments were carried out to elucidate linkage between methane consumption and mineralization of phosphorous (P) from different P sources. The treatments were (i) no CH₄ + no P amendment (absolute control), (ii) with CH₄ + no P amendment (control), (iii) with CH₄ + inorganic P as Ca₃(PO₄)₂, and (iv) with CH₄ + organic P as sodium phytate. P sources were added at 25 µg P·(g soil)^-1. Soils were incubated to undergo three repeated CH₄ feeding cycles, referred to as feeding cycle I, feeding cycle II, and feeding cycle III. CH₄ consumption rate k (µg CH₄ consumed·(g soil)^-1·day^-1) was 0.297 ± 0.028 in no P amendment control, 0.457 ± 0.016 in Ca₃(PO₄)₂, and 0.627 ± 0.013 in sodium phytate. Rate k was stimulated by 2 to 6 times over CH₄ feeding cycles and followed the trend of sodium phytate > Ca₃(PO₄)₂ > no P amendment control. CH₄ consumption stimulated P solubilization from Ca₃(PO₄)₂ by a factor of 2.86. Acid phosphatase (µg paranitrophenol released·(g soil)^-1·h^-1) was higher in sodium phytate than the no P amendment control. Abundance of 16S rRNA and pmoA genes increased with CH₄ consumption rates. The results of the study suggested that CH₄ consumption drives mineralization of unavailable inorganic and organic P sources in the soil ecosystem.

Characterization of Crude Oil Degrading Bacteria Isolated from Contaminated Soils Surrounding Gas Stations

A total of twenty bacterial cultures were isolated from hydrocarbon contaminated soil. Of the 20 isolates, RAM03, RAM06, RAM13, and RAM17 were specifically chosen based on their relatively higher growth on salt medium amended with 4 % crude oil, emulsion index, surface tension, and degradation percentage. These bacterial cultures had 16S rRNA gene sequences that were most similar to Ochrobactrum cytisi (RAM03), Ochrobactrum anthropi (RAM06 and RAM17), and Sinorhizobium meliloti (RAM13) with 96 %, 100 % and 99 %, and 99 % similarity. The tested strains revealed a promising potential for bioremediation of petroleum oil contamination as they could degrade >93 % and 54 % of total petroleum hydrocarbons (TPHs) in a liquid medium and soil amended with 4 % crude oil, respectively, after 30 day incubation. These bacteria could effectively remove both aliphatic and aromatic petroleum hydrocarbons. In conclusion, these strains could be considered as good prospects for their application in bioremediation of hydrocarbon contaminated environment.

Molecular diagnosis and genetic diversity of tick-borne Anaplasmataceae agents infecting the African buffalo Syncerus caffer from Marromeu Reserve in Mozambique

Background

Tick-borne diseases (TBDs) are very important in relation to domestic ruminants, but their occurrence among wild ruminants, mainly in the African buffalo Syncerus caffer, remains little known.

Methods

Molecular diagnostic methods were applied to detect Anaplasma marginale, Anaplasma centrale, Anaplasma phagocytophilum, Ehrlichia ruminantium and Ehrlichia chaffeensis in 97 blood samples of African buffalo captured at the Marromeu Reserve in Mozambique. Molecular detection of agents belonging to the family Anaplasmataceae were based on conventional and qPCR assays based on msp5, groEL, 16S rRNA, msp2, pCS20 and vlpt genes. Phylogenetic reconstruction of new Anaplasma isolates detected in African buffalo was evaluated based on msp5, groEL and 16S rRNA genes.

Results

All the animals evaluated were negative for specific PCR assays for A. phagocytophilum, E. ruminantium and E. chaffeensis, but 70 animals were positive for A. marginale, showing 2.69 × 10⁰ up to 2.00 × 10⁵msp1β copies/μl. This result overcomes the conventional PCR for A. marginale based on msp5 gene that detected only 65 positive samples. Sequencing and phylogenetic analyses were performed for selected positive samples based on the genes msp5, groEL and 16S rRNA. Trees inferred using different methods separated the 29 msp5 sequences from buffalo in two distinct groups, assigned to A. centrale and A. marginale. The groEL sequences determined for African buffalo samples revealed to be more heterogeneous and inferred trees could not assign them to any species of Anaplasma despite being more related to A. marginale and A. centrale. The highly conserved 16S rRNA gene sequences suggested a close relationship of the new 16 sequences with A. centrale/A. marginale, A. platys and A. phagocytophilum.

Conclusions

Our analysis suggests that different species of Anaplasma are simultaneously present in the African buffalo. To the best of our knowledge, this is the first study that diagnosed Anaplasma spp. in the African buffalo and inferred the taxonomic status of new isolates with different gene sequences. The small fragment of msp5 sequences revealed to be a good target for phylogenetic positioning of new Anaplasma spp. isolates.

Identification of clinically relevant Corynebacterium strains by Api Coryne, MALDI-TOF-mass spectrometry and molecular approaches

We evaluated the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) for the identification of 97 Corynebacterium clinical in comparison to identification strains by Api Coryne and MALDI-TOF-MS using 16S rRNA gene and hypervariable region of rpoB genes sequencing as a reference method. C. striatum was the predominant species isolated followed by C. amycolatum. There was an agreement between Api Coryne strips and MALDI-TOF-MS identification in 88.65% of cases. MALDI-TOF-MS was unable to differentiate C. aurimucosum from C. minutissimum and C. minutissimum from C. singulare but reliably identify 92 of 97 (94.84%) strains. Two strains remained incompletely identified to the species level by MALDI-TOF-MS and molecular approaches. They belonged to Cellulomonas and Pseudoclavibacter genus. In conclusion, MALDI-TOF-MS is a rapid and reliable method for the identification of Corynebacterium species. However, some limits have been noted and have to be resolved by the application of molecular methods.