The rice-fish symbiosis farming model (RFFM) has been shown to enhance gut microbial diversity and improve immunity in fish. To examine changes in gut microbiota and hepatic metabolism in yellow catfish (Pelteobagrus fulvidraco) during different rice growth stages, we analyzed samples collected from the pre-flowering (Group P) and after-flowering (Group A) phases. Gut microbiota composition was assessed using 16S rRNA sequencing, with data analyzed using Principal component analysis (PCA), while hepatic metabolic profiles were characterized through untargeted metabolomics using XCMS and metaX for data processing. Our results revealed a significant increase in gut microbial diversity in Group A. Notably, the relative abundances of Pseudomonas and Cetobacterium were significantly lower in Group A compared to Group P, whereas Brevundimonas, Oxyphotobacteria_unclassified, and Clostridium_sensu_stricto_1 were more abundant in Group A. Hepatic metabolic profiles also differed between the two groups, with amino acid metabolism and related pathways being upregulated, while lipid metabolism and associated pathways were downregulated in Group A. Correlation analysis using SPSS suggested that Clostridium_sensu_stricto_1, a dominant bacterial group, played a key role in mediating hepatic metabolic changes under the RFFM. These findings indicate that rice flowering in the rice-fish symbiosis system positively influences gut microbiota composition and hepatic metabolism in yellow catfish. Furthermore, Clostridium_sensu_stricto_1 may have potential as a probiotic for improving fish health in this integrated farming system.

Rice-fish symbiosis is an ecological farming model that can improve fish’s muscle nutrient profile and intestinal flora. We investigated the effect of rice-fish symbiosis on tilapia’s intestinal flora and muscle nutrients. We used 16S rDNA technology to analyze the intestinal flora of tilapia in pond culture and rice-fish symbiosis. Furthermore, spearman correlation analysis was performed on tilapia intestinal flora and muscle nutrients. The results showed that the contents of Valine, Phenylalanine, and Docosahexaenoic acid were significantly higher in the rice-fish symbiosis than those in the pond culture ( p <0.05). Intestinal flora analysis showed that the diversity in rice-fish symbiosis was significantly higher than in pond culture ( p <0.05). Meanwhile, the abundance of Brevundimonas , Pseudomonas , and Ralstonia in rice-fish symbiosis was significantly higher than those in pond culture ( p <0.05), but Pirellulaceae unclassified and Cyanobium_PCC-6307 were opposite. The number of 8 predictive functional tilapia genes in the rice-fish symbiosis was higher than in the pond culture. Correlation analysis showed that the abundance of Ralstonia was positively correlated with the contents of Valine, Phenylalanine, and Docosahexaenoic acid, respectively. Our study shows that the rice-fish symbiosis could improve muscle nutrient profile and intestinal flora diversity in tilapia. This study will help to improve the rice-fish symbiosis model and provide a scientific basis for ecological aquaculture and healthy fish production.

This study aimed to evaluate the effects of different grinding sieve openings (SO), conditioning temperatures (CTP), and conditioning times (CTM) on feed processing performance, growth performance, meat quality, and serum biochemical indices of broiler chickens fed a diet in which 50 % of corn was replaced with aged paddy rice. A total of 960 white-feathered broiler chickens were randomly divided into 8 groups, with the experiment designed to test 2 SO sizes (2.0 mm and 2.5 mm), 2 CTPs (75 °C and 85 °C), and 2 CTMs (90 s and 180 s). The results showed that the 2.0 mm SO and 180 s CTM significantly improved pellet hardness and the pellet durability index (PDI) (P < 0.05). During the early stages of the experiment, when the broilers digestive systems were not fully developed, a 2.5 mm SO significantly reduced the feed conversion ratio (FCR) (P < 0.001), while 75 °C CTP significantly increased average daily gain (ADG) and body weight (BW) at day 21 (P < 0.05). Additionally, 75 °C CTP significantly reduced the cecum organ weight ratio (P < 0.05). In terms of meat quality, a 2.5 mm SO significantly reduced drip loss and cooking loss at 48 h and 72 h (P < 0.01, P < 0.01, P < 0.05), while a 90 s CTM significantly reduced drip loss and cooking loss at 24 h (P < 0.05, P < 0.01). Furthermore, the combination of 2.5 mm SO and 90 s CTM significantly increased serum urea nitrogen (BUN) levels (P < 0.05). Considering the optimization of both growth performance and meat quality, the combination of 2.5 mm SO, 75 °C CTP, and 90 s CTM is recommended for optimizing aged paddy rice feed processing and enhancing broiler growth performance and meat quality.