As the global climate changes, high temperatures will cause heat stress, which significantly affects the productive efficiency of livestock. Currently, there is a lack of efficient methods to use in targeting this issue. In this study, we report that melatonin supplementation may represent an alternative method to reduce the negative impact of heat stress on livestock, particularly in Hainan black goats. Our results show that melatonin treatment increased the average daily gain of Hainan black goats that were exposed to constantly high temperatures for two months compared to controls. Our mechanistic exploration revealed that melatonin treatment not only reduced the oxidative stress and inflammatory reaction caused by heat stress but also improved goats’ metabolic capacity, promoting their growth and development. More importantly, for the first time, we observed that melatonin treatment modified the abundance of the intestinal microflora, altering the metabolism of the goats, which further improved their tolerance to constant heat stress.

Understanding tissue development in pigs is critical for biomedical research and genetic engineering, particularly for modeling human disease. However, tracing developmental origins and reconstructing lineage trees for pig cells remains a significant challenge. Here, we present a high-resolution lineage tracing system that combines molecular barcoding with single-cell transcriptomics in pigs. Our system combines two key components: DNA barcodes (three CRISPR/Cas9 target sites and an 8-base pair intBC) integrated into the genome via piggyBac transposition, and a constitutive Cas9-EGFP cassette stably integrated at the Rosa26 locus using CRISPR/Cas12a. By combining lineage barcodes with single-cell RNA sequencing (scRNA-seq), we constructed an evolutionary lineage recorder that captures distinct cell states across developmental or differentiation trajectories. This system provides an essential tool for the subsequent construction of complete porcine cell fate maps. Our work provides a tool for studying porcine developmental biology, but also helps to optimize regenerative medicine strategies and improve the design of genetically engineered animal models.