Performances of a novel BAF with ferromanganese oxide modified biochar (FMBC) as the carriers for treating antibiotics, nitrogen and phosphorus in aquaculture wastewater.

In this paper, a biological aerated filter (BAF) based on ferromanganese oxide-biochar (FMBC) was constructed to investigated the removal performance and mechanism for conventional pollutants and four kinds of antibiotic, in contrast of conventional zeolite loaded BAF (BAF-A) and bamboo biochar filled BAF (BAF-B). Results showed that the average removal efficiency of total nitrogen (TN), total phosphorus (TP) and antibiotics in a FMBC-BAF (named by BAF-C) were 52.97 ± 2.27%, 51.58 ± 1.92% and 70.36 ± 1.00% ~ 81.65 ± 0.99% respectively in running period (39-100 d), which were significantly higher than those of BAF-A and BAF-B. In the BAF-C, the expression of denitrification enzyme activities and the secretion of extracellular polymeric substance (EPS) especially polyprotein (PN) were effectively stimulated, as well as accelerated electron transfer activity (ETSA) and lower electrochemical impedance spectroscopy (EIS) were acquired. After 100 days of operation, the abundance of nitrogen, phosphorus and antibiotic removal functional bacteria like Sphingorhabdus (4.52%), Bradyrhizobium (1.98%), Hyphomicrobium (2.49%), Ferruginibacter (7.80%), unclassified_f_Blastoca tellaceae (1.84%), norank_f_JG30-KF-CM45 (6.82%), norank_f_norank_o_SBR1031 (2.43%), Nitrospira (2.58%) norank_f_Caldilineaceae (1.53%) and Micropruina (1.11%) were enriched. Mechanism hypothesis of enhanced performances of nutrients and antibiotics removal pointed that: The phosphorus was removed by adsorption and precipitation, antibiotics removal was mainly achieved through the combined action of adsorption and biodegradation, while nitrogen removal was realized by biologic nitrification and denitrification in a FMBC-BAF for aquaculture wastewater treatment.

Effects of dry yeast supplementation on growth performance, rumen fermentation characteristics, slaughter performance and microbial communities in beef cattle.

This study aimed to investigate the effects of active dry yeast (ADY) on growth performance, rumen microbial composition and carcass performance of beef cattle. Thirty-two finishing beef cattle (yak ♂ × cattle-yaks ♀), with an average body weight of 110 ± 12.85 kg, were randomly assigned to one of four treatments: the low plane of nutrition group (control), low plane of nutrition group + ADY 2 g/head daily (ADY2), low plane of nutrition group + ADY 4 g/head daily (ADY4) and the high plane of nutrition group (HPN). Supplementation of ADY increased average daily gain compared to the control group. The neutral detergent fiber and acid detergent fiber apparent digestibility in HPN group was greater than that in control group. The propionic acid concentration in the rumen in ADY2, ADY4, and HPN groups was greater than that in control group. The Simpson and Shannon indexes in control and HPN groups were higher than that in ADY4 group. At the phylum level, the relative abundance of Firmicutes in the HPN group was higher than that in ADY4 group. The relative abundance of Ruminococcaceae UCG-002 in ADY4 group was higher than that in control and HPN groups. In conclusion, supplementation ADY 4 g/head daily shift the rumen microbial composition of beef cattle fed low plane of nutrition to a more similar composition with cattle fed with HPN diet and produce the similar carcass weight with HPN diet.HighlightsThe ADY can improve the utilization of nitrogen and decrease the negative impact on the environment in beef cattle.Cattle fed low plane of nutrition diet supplemented with ADY 4 g/head daily increased growth performance.Supplementation ADY 4 g/head daily in low plane of nutrition diet might be produced comparable carcass weight to HPN diet.

Performances of simultaneous enhanced removal of nitrogen and phosphorus via biological aerated filter with biochar as fillers under low dissolved oxygen for digested swine wastewater treatment.

This study aims to explore the feasibility of biochar as a carrier to improve the simultaneous removal of nitrogen and phosphorus in biological aerated filters (BAFs) for treating low C/N digested swine wastewater (DSW). Two similar BAFs (BAF-A with hydrophobic polypropylene resin as fillers and BAF-B with bamboo biochar as carrier) were developed for DSW treatment. Results showed that the NH4+-N, TN, and TP removal performances in BAF-B were higher than those in BAF-A. Carrier type had an obvious influence on the structures and diversity of the microbial population. The biochar carrier in BAF-B was conducive to the enrichment of the functional microorganisms and the increase of microbial diversity under high NH4+-N conditions. Microbial analysis showed that the genera Rhodanobacter (10.64%), JGI_0001001-h003 (14.24%), RBG-13-54-9 (8.87%), Chujaibacter (11.27%), and Ottowia were the predominant populations involved in nitrogen and phosphorus removal in the later stage of phase III in BAF-B. BAF with biochar as carrier was highly promising for TN and TP removal in low C/N and high NH4+-N DSW treatment.

A hydrolyzed casein diet promotes Ngn3 controlling enteroendocrine cell differentiation to increase gastrointestinal motility in mice.

Gut hormones are produced by enteroendocrine cells (EECs) found along the intestinal epithelium, and these cells play a crucial role in regulating intestinal function, nutrient absorption and food intake. A hydrolyzed casein diet has been reported to promote the secretion of gut hormones through the regulation of EEC development, but the underlying mechanism remains unclear. Therefore, this study was conducted to investigate whether the hydrolyzed casein diet can regulate EEC differentiation by employing mouse and organoid models. Mice were fed diets containing either casein (casein group) or hydrolyzed casein (hydrolyzed casein group) as the sole protein source. The hydrolyzed casein diet upregulated the expression of transcription factors, induced EEC differentiation, increased fasting serum ghrelin concentrations and promoted gastrointestinal (GI) motility in the duodenum compared to the casein diet. Interestingly, these differences could be abolished when there is addition of antibiotics to the drinking water, suggesting a significant role of gut microbiota in the hydrolyzed casein-mediated EEC function. Further investigation showed that the hydrolyzed casein diet led to reduced microbial diversity, especially the abundance of Akkermansia muciniphila (A. muciniphila) on the duodenal mucosa. In contrast, gavage with A. muciniphila impaired EEC differentiation through attenuated neurog3 transcription factor (Ngn3) expression, mediated through the promotion of Notch signaling. Moreover, pasteurized A. muciniphila showed similar effects to enter organoids in vitro. Overall, we found that a hydrolyzed casein diet reduced the abundance of A. muciniphila and promoted Ngn3 controlling EEC differentiation and this pathway is associated with increased GI motility in mice. The findings provide new insights into the role of hydrolyzed casein in gut transit and guidelines for using hydrolyzed casein in safe formula milk.

Comparison of changes in fecal microbiota of calves with and without dam.

In pastoral areas and semi-agricultural and semi-pastoral areas of Sichuan, beef cattle breeding mode is mainly dependent on nature to raise livestock. On the one hand, owing to the shortage of forage grass in spring, cows suffer from malnutrition. On the other hand, competition for milk between human and livestock further deepens the malnutrition of newborn calves, and the mortality rate even exceeds 40%, resulting in serious waste of beef cattle source resources. The objective of this study was to investigate the effect of different cultivation methods (calves with and without dam) and age on calves hindgut microbiome. Sixteen healthy calves (Yak ♂ × Pian cattle ♀, with similar birthday 0 ± 2 d and body weight 13.1 ± 1.13 kg), were selected and randomly divided into two groups. The control group was cultivated with heifers, whereas the treatment group was cultivated without heifers and was fed milk replacer during the whole 95 days formal experimental period. Fecal samples were collected on 35, 65 and 95 days of age for high-throughput sequencing. The α-diversity was different between the two groups on day 35; however, the bacterial species richness and diversity was almost not different on day 95. Principal coordinates analysis revealed significant difference between the two groups on all the three time points, and the timepoints of day 65 and 95 were closer and separated from the timepoints of day 35 in calves with dam, whereas the timepoints of day 35 and 65 were closer and separated from day 95 in calves without dam. As time passed, the abundance of Firmicutes increased, while Proteobacteria and Actinobacteria decreased in calves with dam. But in calves without dam, the abundance of Bacteroidetes and Proteobacteria increased on day 65 and then decreased on day 95. In genus level, the relative abundance of Bacteroides decreased in calf with dam while its abundance increased first and then decreased in calf without dam but both resulted in the range of 3.5~4.5%. The relative abundance of Lactobacillus decreased, whereas Ruminococcaceae UCG-005 increased in both groups as the calf grew up. It was concluded that the richness and evenness of the microbial communities was higher in calves with dam than without dam, and a stable gut microbiome in calve with dam is established earlier than calf without dam.

Responses of Nitrogen and Phosphorus Removal Performance and Microbial Community to Fe3O4@SiO2 Nanoparticles in a Sequencing Batch Reactor.

The responses of total nitrogen (TN) and total phosphorus (TP) removal performance and microbial community to 0-1.2 g/L Fe3O4@SiO2 nanoparticles (NPs) in sequencing batch reactors were investigated. Results showed that an appropriate dose of Fe3O4@SiO2 NPs (0.3 g/L) could promote the removal efficiency of TN and TP. High-throughput sequencing results indicated that microbial richness increased, whereas microbial diversity did not vary upon exposure to 0.1-1.2 g/L Fe3O4@SiO2 NPs. The relative abundances of Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria increased from 11.75%, 3.52%, and 6.77%, respectively, at 0 g/L Fe3O4@SiO2 to 27.05%, 7.21%, and 14.77%, respectively, upon exposure to 0.3 g/L Fe3O4@SiO2. At the genus level, 0.3 g/L Fe3O4@SiO2 NPs enriched norank_f_Nitrosomonadaceae, norank_f_Xanthomonadaceae, Amaricoccus, and Shinella. Real-time quantitative polymerase chain reaction results suggested that the gene copy number of ammonium-oxidizing, nitrite-oxidizing, and denitrifying bacteria population remarkably increased, whereas the number of phosphorus-accumulating organisms slightly increased under long-term exposure to 0.3 g/L Fe3O4@SiO2 NPs. Energy-dispersive spectrum analysis showed that the phosphorus content was higher at 0.3 g/L Fe3O4@SiO2 than at 0 g/L Fe3O4@SiO2. Nitrogen removal primarily occurred through a biological mechanism, while most phosphorus in wastewater may be removed by the combination of physicochemical and biological methods.

Effects of particle size of ground alfalfa hay on caecal bacteria and archaea populations of rabbits.

This work was aimed to investigate the effects of the different particle size of ground alfalfa hay on caecal microbial and archeal communities of rabbits. One hundred-twenty New Zealand rabbits (950.3 ± 8.82 g) were allocated into four treatments, with five replicates in each treatment and six rabbits in each replicate. The particle sizes of the alfalfa meal in the four treatment diets were 2,500, 1,000, 100 and 10 µm respectively, while the other ingredients were ground through a 2.5 mm sieve. High-throughput sequencing technology was applied to examine the differences in bacteria and methanogenic archaea diversity in the caecum of the four treatment groups of rabbits. A total of 745,946 bacterial sequences (a mean of 31,081 ± 13,901 sequences per sample) and 539,227 archaeal sequences (a mean of 22,468 ± 2,443 sequences per sample) were recovered from twenty-four caecal samples, and were clustered into 9,953 and 2,246 OTUs respectively. A total of 26 bacterial phyla with 465 genera and three archaeal phyla with 10 genera were identified after taxonomic summarization. Bioinformatic analyses illustrated that Firmicutes (58.69% ∼ 68.50%) and Bacteroidetes (23.96% ∼ 36.05%) were the two most predominant bacterial phyla and Euryarchaeota (over 99.9%) was the most predominant archaeal phyla in the caecum of all rabbits. At genus level, as the particle size of alfalfa decreased from 2,500 to 10 µm, the relative abundances of Ruminococcaceae UCG-014 (P < 0.001) and Lactobacillus (P = 0.043) were increased and Ruminococcaceae UCG-005 (P = 0.012) was increased first and then decreased when the alfalfa particle size decreased, while Lachnospiraceae NK4A136 group (P = 0.016), Ruminococcaceae NK4A214 (P = 0.044), Christensenellaceae R-7 group (P = 0.019), Lachnospiraceae other (Family) (P = 0.011) and Ruminococcaceae UCG-013 (P = 0.021) were decreased. The relative abundance of Methanobrevibacter was increased from 62.48% to 90.40% (P < 0.001), whereas the relative abundance of Methanosphaera was reduced from 35.47% to 8.62% (P < 0.001). In conclusion, as the particle size of alfalfa meal decreased, both the bacterial and archaeal population in the caecum of rabbit experienced alterations, however archaea response earlier than bacteria to the decrease of alfalfa meal particle size.

Effects of the particle of ground alfalfa hay on the growth performance, methane production and archaeal populations of rabbits.

The world's annual output of rabbits is over 1.2 billion, therefore this sector is also one of the sources of greenhouse gases in livestock production. One hundred-twenty New Zealand rabbits were allocated into four treatments, five replicates in each treatment and six rabbits in each replicate to examine the effect of grinding alfalfa hay to different sizes on growth performance, methane production and cecal archaeal populations. The particle sizes of the alfalfa meal in the four treatment diets were 2500, 1000, 100 and 10 µm, while the other ingredients were ground through a 2.5 mm sieve. The average daily gain (ADG) and average daily feed intake (ADFI) increased (P<0.001) as the particle size decreased, but the feed conversion ratio (FCR) was not affected (P = 0.305). The digestibility of neutral detergent fiber (NDF) (P = 0.006) and acid detergent fiber (ADF) (P<0.006) increased while the greatest digestibility of crude protein (CP) was obtained in 1000 um group (P = 0.015). The rabbits produced more methane (CH4, L/kgBM0.75/d) with decreasing alfalfa particle size (P<0.001). The molar proportion of acetic acid and propionic acid decreased (P<0.001) at the cost of butyric acid (P<0.001). The greatest villus height:crypt depth ratio were obtained in 1000 µm group, and the decrease in the alfalfa hay particle size decreased the jejunum and ilem villus height:crypt depth ratio (P<0.05). The gastric muscular and mucosal thickness decreased with decreasing alfalfa particle size (P<0.05). Archaea diversity decreased with decreasing alfalfa particle size, and the relative abundance of genus Methanobrevibacter increased (P<0.001) while the genus Methanosphaera decreased (P<0.001). It is concluded that a finer particle size favors the growth of genus Methanobrevibacter, which produces more methane but promotes the growth performance of rabbits.