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Pure yeast β‑glucan (YG1) was obtained by drying and defatting the crude β‑glucan from Saccharomyces cerevisiae. The YG1 structure was characterized by total sugar content, protein content, FT-IR spectroscopy and monosaccharide composition analysis. Different molecular weight fractions of water-soluble yeast β‑glucan (WYG) were prepared by extraction with 2.0 M NaOH, degradation of the insoluble residue with 1.0 M HCl based on single-factor experiments, and fractionation on a size exclusion chromatography column (SEC, Sephacryl S-400). The molecular sizes of as-obtained fractions were measured by multi-angle laser light scattering combined with SEC and differential refractive index detector (SEC-MALLS-RI). Results indicated that YG1 had a high purity and was almost composed of β‑ d ‑glucose (97.71%) except trace mannose. The WYG yields by alkali extraction and acidolysis were 12.41% and 42.85%, respectively. Fourteen fractions with molecular weight (Mw) from 4590 to 31.61 kDa and low polydispersity index (Mw/Mn of ~1) were successfully separated, showing high recovery rates of 61.9–92.5%. Additionally, these fractions could promote the proliferation of RAW264.7 macrophages, and the fraction (Mw = 2496 kDa) exhibited the highest cell viability of 145.8 ± 4.3% at a low concentration of 1.56 μg/mL. This work not only provides an efficient method for separating WYG fractions with different molecular weights and low polydispersity, but also lays a theoretical basis for interpreting the relationship between molecular size and bioactivity.

So far, few animals with the ability of lignin degradation have been reported except termite and longicorn. In this study, it was found that the crude fiber and acid detergent lignin (ADL) of rice straw can be degraded dramatically higher by buffalo than those by cattle. In order to further study this ability of buffalo, the digestion of roughages in buffalo rumen was studied using rumen nylon bag experiment, scanning electron microscopy (SEM), and Van Soest fiber analysis. The SEM results showed that the degradation degree of rice straw was dramatically higher in buffalo than that in cattle. The digestibility of crude fiber was significantly higher in buffalo than that in cattle (P 0.01). The digestibility of ADL, cellulose, hemicellulose, acid detergent, fiber, and neutral detergent fiber of rice straw in buffalo rumen was significantly higher than that in cattle (P 0.05). The ADL degradation rate of rice straw in buffalo rumen was significantly higher than that in cattle rumen, indicating that buffalo was capable of utilizing lignin and had superior utilizing capability than cattle. It was observed that various roughages can be dramatically digested by buffalo rumen with the ranking of ADL degradation rate: peanut vine (15.04%) rice silage maize silage rice straw corn stover wheat stalk bract leaf potato vine (7.22%), verifying that buffalo rumen possessed the ability to digest universal roughages. In conclusion, this study revealed that buffalo was more efficient in ADL degradation compared with cattle.

Although melatonin has been extensively studied in animal reproduction, the mechanism of melatonin in puberty remains elusive. This study was designed to explore the effect of intraperitoneal administration of melatonin on puberty onset in female mice. The injection of melatonin into postnatal days 10 mice at a dose of 15 mg/kg accelerated the puberty onset in mice. Mechanistically, there was no difference in physical growth and serum Leptin levels after melatonin administration. Meanwhile, the serum levels of reproductive hormones involved in hypothalamic-pituitary-ovarian axis, such as FSH and estrogen level in serum were increased. The mRNA levels of GnRH and GnRHr were not affected by melatonin, while the expressions of FSHβ in pituitary and Cyp19a1 in ovary were significantly up-regulated. In addition, melatonin still promoted FSH synthesis after ovariectomy. Furthermore, the enhanced activity of ERK1/2 signaling verified that the expression of FSHβ increased in pituitary. We confirmed that melatonin promoted the FSH synthesis in pituitary, thereby increased serum estrogen levels and ultimately accelerated puberty onset. However, these effects of melatonin may be pharmacological due to the high dose. This study would help us to understand the functions of melatonin in pubertal regulation comprehensively.