Gut microbes may be involved in photoperiod regulation of seasonal reproduction of rodents

Seasonal breeding is a reproductive strategy
adopted by many animals.
It is known that photoperiod is a key factor in regulating seasonal reproduction in animals, and it can regulate the expression of a series of reproductive genes and hormones by affecting the hypothalamic-pituitary-gonadal (HPG) axis, thereby regulating the initiation and termination
of reproduction in animals.
Recent studies have shown that photoperiod can alter the composition of murine gut microbes; Some gut microbes are involved
in processes such as host reproductive hormone secretion and spermatogenesis.
However, whether the gut microbiota is involved in the seasonal reproduction of photoperiod-regulated animals remains unclear
.

Zhang Zhibin's research team from the Institute of Zoology, Chinese Academy of Sciences, took male Bryde's voles that reproduced seasonally in the grasslands of Inner Mongolia as the research object, and studied the relationship
between intestinal microbiota and photoperiod-regulated seasonal reproduction of Bryde's voles through photoperiod manipulation experiments and intestinal microbiota transplantation (FMT) experiments 。 The results showed that short photoperiod significantly reduced weight growth, gonadal (testicular and epididymis) weight, serum hormone levels (including follicle-stimulating hormone, luteinizing hormone, and testosterone), hypothalamic genes (Dio2, Rfrp-3, and Kiss-1) and testes' genes (Dio2, Kiss-1, and GPR54), increased serum melatonin levels, testicular gene (Dio3 and Stra8) expression, and aggressive behavior intensity (Figure 1).

The composition and structure of gut microorganisms are closely related to photoperiod processing (Figure 2).

Through fecal transplantation of long- and short-photoperiod-exposed donor voles, changes in the levels of three reproductive hormones (melatonin, follicle-stimulating hormone and luteinizing hormone) and the expression of three reproductive genes (hypothalamic Kiss-1, testicular Dio3 and Dio2/Dio3 ratio) of recipient voles were found to be consistent with the response of donor voles (Figure 3).

In addition, gut microbial transplantation also altered the rhythm of the activity of recipient voles
.
The results suggest that the gut microbiota may be involved in regulating seasonal reproductive and behavioral activities of rodents through the HPG axis, melatonin, and the Kisspeptin/GPR54 system in the hypothalamus
.

This study provides new ideas and insights for elucidating the interaction between host and intestinal microorganisms in regulating seasonal reproduction and behavior of animals during photoperiod, and has reference significance in pest control, domestic animal breeding and human health management
.

The study was published online on November 15, 2022 in the microbiology journal Microbiome as "Gut microbiota is associated with the effect of photoperiod on seasonal breeding in male Brandt's voles (Lasiopodomys brandtii).
"
。 Zhu Hanyi, a doctoral student at the State Key Laboratory of Integrated Management of Agricultural Pest and Rodent Infestation, Institute of Zoology, Chinese Academy of Sciences, and Li Guoliang, assistant researcher, are co-first authors, and Zhang Zhibin, a researcher at the State Key Laboratory of Integrated Management of Agricultural Pest and Rodent Infestation, Institute of Zoology, Chinese Academy of Sciences, and the Center for Excellence in Biological Interactions, Chinese Academy of Sciences, are the corresponding authors
.
The research was supported
by the National Natural Science Foundation of China (32090021 and 32070460), the Pilot Project of the Chinese Academy of Sciences (XDPB16), and the Program of the Youth Innovation Promotion Association of the Chinese Academy of Sciences (2022081).

Links to papers (with video presentations): https://doi.
org/10.
1186/s40168-022-01381-1

Fig.
1 Changes in growth and development, behavior and reproductive indexes of Bryde's voles under long or short photoperiod treatment

Fig.
2 Changes of intestinal microbial diversity of Bryde's voles and their correlation with reproductive indexes under long or short photoperiod treatment

Fig.
3 Effects of long- or short-photoperiod exposed gut microbial transplantation on growth and development, behavior, and reproductive indicators of Bryde's voles