Chickens are remarkably versatile animals that are used as model organisms for biomedical research. Here, we performed metabolomic and RNA sequencing (RNA-Seq) transcriptomic analyses of the hypothalamus, liver tissue and serum of poultry with different genetic backgrounds, providing detailed information for hypothalamus and liver tissue at the transcriptional level and for liver tissue and serum at the metabolite level. We present two datasets generated from 36 samples from three poultry breeds using high-throughput RNA-Seq and liquid chromatography coupled with mass spectrometry acquisition (LC/MS). The transcriptomic and metabolomic data obtained for poultry of different genetic backgrounds will be a valuable resource for further studies on this model organism.

Fermented feed has considerable potential as a high-quality protein source in animal production. This research aimed to examine the effects of a low-protein (LP) diet, supplemented with fermented feed, on the meat quality and intestinal health of growing–fattening pigs. The pigs were randomly divided into three groups, and a total of 72 growing–fattening pigs were subjected to the experiment. They were fed the control (CON) diet, LP diet, and LP diet supplemented with fermented rapeseed meals and fermented distiller’s grains (FLP), respectively. The results indicated that the FLP diet altered the structure of the intestinal microbiota and regulated the composition of unsaturated fatty acids in the longissimus dorsi. Furthermore, the FLP diet upregulated the expression of genes associated with myosin heavy chain isoforms (p < 0.05) and modified the content of short-chain fatty acids in the intestines (p < 0.05). In summary, the addition of fermented distiller’s grains (FDGs) and fermented rapeseed meals (FRMs) to the LP diet enhanced fatty acid metabolism and intestinal barrier function in growing–fattening pigs.

Rumen development and microecological homeostasis are critical for post-weaning health in lambs; however, effective nutritional strategies combining probiotics and antimicrobial peptides remain underexplored. This study investigated the effects of graded doses of a combined additive (Candida utilis + antimicrobial peptide (AMP)) on rumen development and microecology in weaned Hu lambs. Forty healthy pre-weaning male lambs (initial body weight: 15.77 ± 1.25 kg; age: 42.98 ± 1.80 d) were randomly assigned to four groups (n = 10): a control group (CK, fed milk/basal diet), and three treatment groups receiving the same milk/basal diet supplemented with graded doses of the combined additive, based on feed intake (LCB: AMP 0.05 g/kg + C. utilis 0.1 g/kg, MCB: AMP 0.05 g/kg + C. utilis 0.8 g/kg, HCB: AMP 0.05 g/kg + C. utilis 1.5 g/kg) over a 40-day period starting from day 6. At the end of the trial, six lambs per group were randomly selected for sampling for analyses of rumen morphology, fermentation parameters, 16S rRNA amplicon sequencing, and untargeted metabolomics. Results showed that, compared with CK, (1) MCB and HCB increased papilla height, and HCB also increased papilla width (p < 0.05); papilla width and muscular layer thickness showed significant linear increases with increasing additive dose (p < 0.05). (2) All treatments linearly reduced ruminal pH (p < 0.05), although all values remained within the normal physiological range; meanwhile, all treatment groups showed elevated levels of microbial protein (MCP), butyrate, valerate, and isovalerate; MCP also increased linearly with dose (p < 0.05); LCB decreased the acetate-to-propionate ratio(A:P), and this ratio exhibited a significant quadratic trend across treatment groups (p < 0.05). (3) HCB increased the α-diversity indices and reduced Methanobacteriota abundance; LCB elevated Bacillota; and all treatments decreased Spirochaetota, Synergistota, and Cyanobacteriota but increased Actinomycetota, Verrucomicrobiota, and Thermodesulfobacteriota (p < 0.05). (4) The number of differential metabolites and KEGG pathway enrichments gradually increased with increasing doses of the combined additive, with HCB exerting the most extensive modulatory effects on signaling and neural pathways. (5) Volatile fatty acids, Bacteroidota, and Xylanibacter were positively correlated with rumen development parameters (p < 0.05). Collectively, dietary supplementation with the combined additive improved rumen fermentation, microbial community structure, and metabolic profiles, with the high-dose (HCB) regimen showing the most effects on select parameters, whereas the low-dose (LCB) regimen exhibited advantages in specific fermentation traits. These findings provide preliminary evidence for the potential application of this combined additive in post-weaning lamb diets.