SARS-CoV-2 Structural Proteins Modulated Blood-Testis Barrier-Related Proteins through Autophagy in the Primary Sertoli Cells.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) disrupts the blood-testis barrier (BTB), resulting in alterations in spermatogenesis. However, whether BTB-related proteins (such as ZO-1, claudin11, N-cadherin, and CX43) are targeted by SARS-CoV-2 remains to be clarified. BTB is a physical barrier between the blood vessels and the seminiferous tubules of the animal testis, and it is one of the tightest blood-tissue barriers in the mammalian body. In this study, we investigated the effects of viral proteins, via ectopic expression of individual viral proteins, on BTB-related proteins, the secretion of immune factors, and the formation and degradation of autophagosomes in human primary Sertoli cells. Our study demonstrated that ectopic expression of viral E (envelope protein) and M (membrane protein) induced the expressions of ZO-1 and claudin11, promoted the formation of autophagosomes, and inhibited autophagy flux. S (spike protein) reduced the expression of ZO-1, N-cadherin, and CX43, induced the expression of claudin11, and inhibited the formation and degradation of autophagosomes. N (nucleocapsid protein) reduced the expression of ZO-1, claudin11, and N-cadherin. All the structural proteins (SPs) E, M, N, and S increased the expression of the FasL gene, and the E protein promoted the expression and secretion of FasL and TGF-ß proteins and the expression of IL-1. Blockage of autophagy by specific inhibitors resulted in the suppression of BTB-related proteins by the SPs. Our results indicated that SARS-CoV-2 SPs (E, M, and S) regulate BTB-related proteins through autophagy.

Protective effects of dietary betaine on intestinal barrier function and cecal microbial community in indigenous broiler chickens exposed to high temperature environment.

High temperature environment causes reduction in productivity in broilers by disrupting the intestinal barrier function. This study aimed to investigate the protective effects of dietary betaine on intestinal barrier function and cecal microbial community in indigenous broilers (Huaixiang chickens) exposed to high temperature environment. A total of 144 5-week-old male broilers (average initial body weight of 401.62 ± 9.51 g) were randomly allocated to three treatments for 10 weeks feeding trial; each treatment contained six replicates with eight birds per replicate. The three treatments included normal temperature control group (NT, fed basal diet, 26 ± 1 °C), high temperature control group (HT, fed basal diet, 32 ± 1 °C for 8 h/day), and HT group supplemented 1000 mg/kg betaine (HTB). The results showed that high temperature environment reduced the Occludin, Claudin-4, and ZO-1 expressions in duodenal mucosa (P < 0.05). Dietary betaine improved the Claudin-4 and ZO-1 expressions of duodenal mucosa (P < 0.05). In jejunal mucosa, HT group had lower Occludin, Claudin-1, Claudin-4, and ZO-1 expressions than NT group (P < 0.05). Compared with HT group, HTB group had higher Occludin and ZO-1 expression (P < 0.05). In ileal mucosa, the relative mRNA expression of ZO-1 in HT group was lower than those in NT group (P < 0.01), and dietary betaine (HTB group) improved ZO-1 expression compared with HT group (P < 0.05). Based on the results of 16S rRNA sequencing, the enriched and dominant microbials in NT group are Epsilonbacteraeota, Bacteroidetes, and Gammaproteobacterial, the enriched and dominant microbial in HT group is Muribaculaceae, and Firmicutes is the enriched and dominant microbial in HTB group. Taken together, the findings revealed that dietary betaine improved the intestinal barrier function and cecal microbial community in indigenous broilers under high ambient temperature.

New insights into the role of dietary marine-derived polysaccharides on productive performance, egg quality, antioxidant capacity, and jejunal morphology in late-phase laying hens.

The present study was conducted to evaluate the effects of dietary marine-derived polysaccharides (MDP) from seaweed Enteromorpha on productive performance, egg quality, antioxidant capacity, and jejunal morphology in late-phase laying hens. A total of 240 Lohmann white laying hens (62 wk of age) were assigned to 4 dietary treatments that included MDP at concentrations of 0, 1,000, 2,500, and 5,000 mg/kg for 6 wk. Each treatment had 6 replicates with 5 cages (2 birds/cage). The results showed that dietary MDP quadratically improved egg production (P < 0.05) during 5 to 6 wk and 1 to 6 wk. There was a linear reduction in cracked egg rate (P < 0.05) with dietary MDP levels increased during 3 to 4 wk and 1 to 6 wk. After 4 wk of feeding trial, the egg shell thickness, yolk color, and Haugh unit showed a linear increase (P < 0.05) in response to increasing dietary MDP levels. Besides, the egg shell breaking strength, egg shell thickness, yolk color, and Haugh unit were improved linearly (P < 0.05) by dietary MDP at the end of the experiment. Moreover, dietary MDP showed a linear and quadratic reduction in serum malondialdehyde (MDA) content (P < 0.05) at the end of third week. At the end of experiment, the activity of total superoxide dismutase in serum was increased quadratically (P < 0.05) by dietary MDP, and dietary MDP quadratically improved the liver catalase (CAT) activity (P < 0.05) and linearly enhanced jejunal CAT activity (P < 0.05), whereas linearly decreased jejunal MDA concentration (P < 0.05). Furthermore, supplemental MDP linearly improved the villus height (P < 0.05) and quadratically increased villus height/crypt depth ratio (P < 0.05) of jejunum. However, dietary MDP had no effect on jejunal trypsin, amylase, and protease activity (P > 0.10). Taken together, these findings provided new insights into the role of MDP in improving the productive performance, egg quality, antioxidant capacity, and jejunal morphology of late-phase laying hens.

Sodium butyrate as an effective feed additive to improve growth performance and gastrointestinal development in broilers.

This study was conducted to evaluate the effects of dietary sodium butyrate (SB) supplementation on growth performance, the development of gastrointestinal tract and immune organs (thymus, spleen and bursa of fabricius), and serum antibody titer after Newcastle disease (ND) vaccination in broilers. The total of 288 1-day-old broilers were randomly allocated to four groups with six replications according to initial body weight. Four treatment groups were designed as follows and fed the indicated diets: CON, basal diet; T1, basal diet supplemented with 0.3 g/kg SB; T2, basal diet supplemented with 0.6 g/kg SB; T3, basal diet supplemented with 1.2 g/kg SB. During days 1-21, broilers fed the T2 diet had higher (p < .05) average daily gain (ADG) than broilers fed the CON diet. On day 21, dietary SB supplementation showed linear increase (p < .05) in relative weight of the duodenum, jejunum, ileum, small intestine (the sum weight of duodenum, jejunum and ileum), pancreas and thymus, and linear increase (p < .05) in relative length of the duodenum, jejunum, ileum, small intestine (the sum length of duodenum, jejunum and ileum) and caeca. Meanwhile, dietary SB supplementation showed linear increase in the antibody titer against ND on days 14, 21, 28 and 35. In conclusion, dietary SB supplementation improved the development of gastrointestinal by increasing the relative weight and length, as well as enhanced the immune response of ND vaccine.

A genetics laboratory class to analyze early and late feather traits of chicken.

With the implementation of the "Education and Training Program for Outstanding Agricultural and Forestry Talents" in our country, our university established the "Outstanding Class" for students majoring in the animal science. We also carried out a series of educational management and curriculum reforms to cultivate students' systematic model of thinking and the ability of technology innovation. In this paper, we designed a comprehensive experiment that focused on analyzing early and late feather genetic traits of chicken. The students initially observed the phenotype of chickens and gradually were led into genetics analysis. We introduced the breeding practice, and guided the students to use genetic theories to breed chick strains of early and late feather traits. The experiment is not only based on the sex-linkage theory and sex determination mechanism, but also molecular genetics technologies, such as genomic DNA extraction, amplification, enzyme digestion and electrophoresis. Conducting this experiment can enhance students' comprehensive analysis ability and professional skills, as well as be beneficial to cultivate their scientific research interests and curiosity on animal sciences. Thus, we integrated the genetics theories into animal breeding practice that meet the requirement of comprehensive applied talents of animal science specialty. The teaching ideas and methods described in this paper can be applied to other biological experiment teaching practice.

[Establishment of the isolation and culture system for monocloning human pancreatic stem cell].

The present study aimed to establish an isolation and culture system for the monoclonal human pancreatic stem cells and monoclonal human pancreatic stem cell line. Some factors which would influence the proliferation of the monoclonal human pancreatic stem cells were assessed. Pancreatic tissues, taken from abortive fetuses by sterile procedures, were dissected into 1 mm3 segments and digested with 0.1% type IV collagenase. The isolated cells were grown in media containing low glucose Dulbecco's Modified Eagles's Medium supplemented with 10% fetal bovine serum (FBS), 3.7 g/L sodium pyruvate, 0.08 g/L penicillin and 0.1 g/L streptomycin. These cells were further digested with 0.25 g/L trypsin and 0.4 g/L EDTA for propagation. The monoclonal human pancreatic stem cells were selected by clone-ring, and further proliferated after addition of 10 ng/mL epidermal growth factor (EGF) in culture media. The cell chromosome set was determined by karyotype analysis. The growth curve was made by the 3-(4, 5)-dimethylthiahiazo (-z-yl)-3, 5-di-phenytetrazoliumromide (MTT) method. The results showed that pancreatic tissues were digested to many single cells and cell clusters with collagenase. Adherently cultured, primary epidermal-like pancreatic stem cells grew clonally. After several times of dissociation and propagation, pancreatic stem cells were gradually purified during generations. Using clone-ring selection, the monoclonal human pancreatic stem cells were obtained. Continuously propagated, a monoclonal human pancreatic stem cell line which was derived from a male abortive fetus of 4 month-old had been passed through 50 generations. Karyotype analysis demonstrated that the chromosome set of the monoclonal human pancreatic stem cell line was normal diploid. Growth curve revealed that monoclonal human pancreatic stem cells grew slowly in initial 1-4 days. Then, they entered the logarithmic growth period in next 5-6 days. Their proliferation was speeded up by supplementation with 15% FBS in culture media, which was even more quickly after addition of the 15 ng/mL EGF or 10 ng/mL insulin growth factor II (IGF-II). The result identified that the monoclonal human pancreatic stem cell line could be obtained by the cell isolation and culture system.

[Research on differentiation features of the monoclonal human pancreatic stem cell].

The in vitro and in vivo differentiation features of the monoclonal human pancreatic stem cell (mhPSC) line derived from the pancreatic tissues of a male abortive fetus at 4 month-old were studied. The mhPSCs were plated in culture dishes that had been coated with 0.1% gelatin in phosphate-buffered saline without calcium and magnesium. After proliferated for 3 days, the mhPSCs were induced in modified high-glucose Dulbecco's Modified Eagles's Medium for 25 days. The changes of the cell morphology were observed by phasecontrast microscope during inducement course. The results of the mhPSCs in vitro induced to differentiate into functional pancreatic islets were identified using dithizone staining, RT-PCR and stimulation-glucose secreting insulin and C-peptide radioimmunoassay. The mhPSCs suspension was separately injected under the groin hypoderm of male nude mice. On the 30th day, the grafts were taken off. The immunochemistry reactions were performed by the SP method. The in vivo differentiation ability of the mhPSCs in nude mice was assessed. In vitro proliferation culture, the mhPSCs adhesively grew and showed polygon epithelioid morphology. After proliferation a layer, the mhPSCs showed the gravelstone-like. During in vitro directional inducement, the mhPSCs gradually turned from polygon to round, suspended to grow and assembled pancreatic islets-like clusters. On the 15th inducement day, only a few cells of pancreatic islet-like clusters were induced into the beta cells that became crimson with dithizone staining. However, till the 25th inducement day, most cells of pancreatic islet-like clusters had differentiated into the beta cells, as identified by dithizone staining, which expressed transcription factor of insulin. Respectively stimulated with different concentration glucose, the induced pancreatic islets not only secreted insulin and C-peptide, but also the secretion volumes of the insulin and C-peptide were markedly increased after the stimulation with higher concentration glucose (0.01