High‐temperature environment‐induced heat stress (HS) is a hazard environmental element for animals, leading to dramatic changes in physiological and metabolic function. However, the metabolomic‐level mechanisms underlying lipid metabolism in liver of slow‐growing broilers are still obscure. The present study investigated the effects of HS on hepatic lipidomics in Chinese indigenous slow‐growing broilers (Huaixiang chickens). The study includes two treatments, each treatment had 5 replicates with 4 broilers per cage, where a total of 40 eight‐week‐old female Huaixiang chickens (average initial body weight of 840.75 ± 20.79 g) were randomly divided into normal temperature (NT) and HS groups for 4 weeks, and the broilers of NT and HS groups were exposed to 21.3 ± 1.2℃ and 32.5 ± 1.4℃ respectively. The relative humidity of the two groups was maintained at 55%–70%. The liquid chromatography‐mass spectrometry (LC‐MS)‐based metabolomics were conducted to evaluate the changes in hepatic lipidomics of broilers. The results showed that there were 12 differential metabolites between the two treatments. Compared with the NT group, HS group reduced the levers of hepatic phosphatidylcholine (PC) (16:0/16:0), PC (16:0/18:2), triglyceride (TG) (16:0/16:1/18:1), TG (18:0/18:1/20:4) (VIP > 1 and p < 0.05), while increased PC (18:1/20:3), PC (18:0/18:1), PC (18:1/18:1), PC (18:0/22:5), dimethyl‐phosphatidyl ethanolamine (dMePE) (14:0/18:3), dMePE (18:0/18:1) and dMePE (16:0/20:3) levels (Variable Importance in the Projection; VIP > 1 and p < 0.05). In addition, according to the analysis of metabolic pathway, the pathways of linoleic acid, alpha‐linolenic acid, glycerolipid and glycerophospholipid metabolism were involved in the effects of HS on hepatic lipid metabolism of broilers (p < 0.05). In conclusion, HS altered the hepatic lipid metabolism mainly through linoleic acid, alpha‐linolenic acid, glycerolipid and glycerophospholipid metabolism pathway in indigenous broilers. These findings provided novel insights into the role of HS on hepatic lipidomics in Chinese indigenous broiler chickens.

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The Caohai is a typical natural lake-type karst plateau wetland, which is sensitive to environmental changes, and the release of dissolved organic nitrogen (DON) in the sediment is a potential factor of nitrogen pollution in the lake. Therefore, this study aimed to reveal the temporal and spatial distribution characteristics and source analysis of DON in karst lake sediments. Surface sediment samples were collected from the Caohai Lake in southwest China, and the sample locations were distributed across almost the entire wetland area during both the wet and dry seasons. The DON content and uorescence spectroscopy were determined and analysed using a three-dimensional uorescence-parallel factor analysis (3DEEM-PARAFAC) model. The mean DON content in the sediment during the dry season (67.79 mg/kg) was higher than in the wet season (28.57 mg/kg). There were four uorescent components of DON in the sediment: C1 (tyrosine-like protein), C2 (terrestrial humus), C3 (tryptophan-like protein), and C4 (terrestrial humus). The maximum uorescence intensity of each component in both seasons showed the trend of C2 > C1 > C3 > C4. The DON in the surface sediment of the Caohai Lake was in uenced by terrestrial sources and biological activities. These ndings help reveal the circulation mechanism of endogenous nitrogen in the lake and provide theoretical support for the prevention and control of nitrogen pollution in the Caohai Lake.