The gut microbiota constitutes a complex ecosystem, comprising trillions of microbes that have co-evolved with their host over hundreds of millions of years. Over the past decade, a growing body of knowledge has underscored the intricate connections among diet, gut microbiota, and human health. Bioactive polysaccharides (BPs) from natural sources like medicinal plants, seaweeds, and fungi have diverse biological functions including antioxidant, immunoregulatory, and metabolic activities. Their effects are closely tied to the gut microbiota, which metabolizes BPs into health-influencing compounds. Understanding how BPs and gut microbiota interact is critical for harnessing their potential health benefits. This review provides an overview of the human gut microbiota, focusing on its role in metabolic diseases like obesity, type II diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular diseases. It explores the basic characteristics of several BPs and their impact on gut microbiota. Given their significance for human health, we summarize the biological functions of these BPs, particularly in terms of immunoregulatory activities, blood sugar, and hypolipidemic effect, thus providing a valuable reference for understanding the potential benefits of natural BPs in treating metabolic diseases. These properties make BPs promising agents for preventing and treating metabolic diseases. The comprehensive understanding of the mechanisms by which BPs exert their effects through gut microbiota opens new avenues for developing targeted therapies to improve metabolic health.

The gut microbiota constitutes a complex ecosystem, comprising trillions of microbes that have co-evolved with their host over hundreds of millions of years. Over the past decade, a growing body of knowledge has underscored the intricate connections among diet, gut microbiota, and human health. Bioactive polysaccharides (BPs) from natural sources like medicinal plants, sea-weeds, and fungi have diverse biological functions, including antioxidant, immunoregulatory, and metabolic activities. Their effects are closely tied to the gut microbiota, which metabolizes BPs into health-influencing compounds. Understanding how BPs and gut microbiota interact is critical for harnessing their potential health benefits. This review provides an overview of the human gut microbiota, focusing on its role in metabolic diseases like obesity, type II diabetes mellitus (T2DM), non-alcoholic fatty liver disease (NAFLD), and cardiovascular diseases (CVD). It explores the basic characteristics of several BPs and their impact on gut microbiota. Given their significance for human health, we summarize the biological functions of these BPs, particularly in terms of im-munoregulatory activities, blood sugar, and hypolipidemic effect, providing a valuable reference for understanding the potential benefits of natural BPs in treating metabolic diseases. These properties make BPs promising agents for preventing and treating metabolic diseases. The comprehensive understanding of the mechanisms by which BPs exert their effects through gut microbiota opens new avenues for developing targeted therapies to improve metabolic health.

Entamoeba spp. is a common zoonotic intestinal protozoan that can parasitize most vertebrates, including humans and pigs, causing severe intestinal diseases and posing a serious threat to public health. However, the available data on Entamoeba spp. infection in pigs are relatively limited in China. To characterize the infection of Entamoeba spp. within pigs in southern China, 1254 fecal samples of diarrheic pigs were collected from 37 intensive pig farms in Hunan, Jiangxi and Fujian provinces and the infection of Entamoeba spp. was investigated based on the small subunit rRNA (SSU rRNA) gene. The overall infection rate of Entamoeba spp. was 58.4% (732/1254), including 38.4% (118/307) in suckling piglets, 51.2% (153/299) in weaned piglets, 57.9% (55/95) in fattening pigs and 73.4% (406/553) in sows, respectively. Moreover, age and the sampling cities in Jiangxi and Fujian provinces were found to be the key factors influencing the infection of Entamoeba spp. (p < 0.05). Two subtypes (ST1 and ST3) with a zoonotic potential of Entamoeba polecki and Entamoeba suis were detected in all age groups of pigs and all sampling areas, with the predominant species and predominant subtype being E. polecki (91.3%, 668/732) and E. polecki ST1 (573/668), respectively, and E. polecki ST1 + E. polecki ST3 (78.6%, 239/304) being the most frequently detected form of mixed infection. Severe Entamoeba spp. infection and zoonotic subtypes were found in this study, exposing a large public health problem in the study area, and strategies need to be implemented to eliminate the risk in the future.

Alpha-ketoglutaric acid (AKG) is a key intermediate in the tricarboxylic acid cycle and plays a crucial role in energy production and amino acid metabolism. This study aimed to evaluate the effects of AKG on growth performance, nutrient digestibility, plasma biochemical parameters, and plasma amino acid profiles in weaned piglets. A total of 72 weaned piglets with an average weight of 7.33 kg (±0.50 kg) and an average age of 28 (±2 days) were randomly assigned to 3 dietary treatments with 6 replicates per group in a 42-day trial. The treatments included a basal diet (CT), a basal diet with 500 g/t AKG (AKG1), and a basal diet with 1000 g/t AKG (AKG2). Blood samples were collected on days 14 and 42, and fecal samples were collected on day 42. The results showed that diets including 500 g/t and 1000 g/t AKG significantly reduced diarrhea incidence in piglets compared to the CT group (p < 0.01). Moreover, diets including 1000 g/t AKG enhanced fecal dry matter digestibility, plasma albumin (ALB), and glucose (GLU) concentrations on day 42 compared to the AKG1 group (p < 0.05). In conclusion, diets including AKG reduced diarrhea incidence in weaned piglets, potentially through improved nutrient digestibility and enhanced systemic health. The 1000 g/t level exhibited greater beneficial effects than 500 g/t.

Immunologically active peptides (IAP) are important bioactive peptides with potential antioxidant, anti-inflammatory, and immunomodulatory properties. However, their application in broiler production has not been systematically evaluated. This study investigated the effects of dietary IAP supplementation on growth performance, carcass traits, meat quality, selected serum biochemical indices, and ileum inflammatory cytokine expression in broilers. A total of 180 one-day-old Ross 308 male broilers were randomly assigned to 3 dietary treatments with 6 replicates per group for 42 d: a basal diet (CON), and the basal diet supplemented with 500 g/t or 1000 g/t IAP. Overall treatment tendencies were observed for final body weight (BW) and average daily gain (ADG) (p = 0.100; p = 0.096), with numerically higher values observed in broilers receiving 500 g/t IAP. Dietary supplementation with 500 g/t IAP significantly improved feed conversion ratio (p < 0.05). Across increasing dietary IAP levels, significant quadratic responses were observed for final BW, ADG, and FCR (p < 0.05), indicating nonlinear responses to increasing IAP supplementation levels. In addition, serum superoxide dismutase (SOD) activity was significantly increased in broilers receiving 500 g/t IAP compared with the control group (p < 0.05), and a significant quadratic response was observed across dietary IAP levels (p < 0.05). Furthermore, dietary IAP supplementation significantly reduced ileum interleukin-1β (IL-1β) mRNA expression in the 500 g/t group (p < 0.05), and IL-1β expression exhibited a significant quadratic response across IAP supplementation levels (p < 0.05). In conclusion, dietary supplementation with IAP, particularly at 500 g/t, improved feed efficiency, increased serum SOD activity, and reduced ileal IL-1β mRNA expression in broilers without compromising carcass characteristics or meat quality. These findings indicated that IAP has potential as a functional feed additive for further evaluation in broiler production.

Alpha-ketoglutarate (AKG) supplementation has been explored as a nutritional strategy to mitigate the negative effects of protein restriction. This study aims to evaluate the effects of supplementing a low-protein diet with AKG on growth performance, diarrhea incidence, and fecal nutrient digestibility in weaned piglets. A total of 60 weaned piglets (initial body weight: 7.53 kg; age: 28 days old) were randomly distributed into three dietary treatments with five replicates per group, for a 42-day experimental period. The treatments consisted of a control diet (CT), a low-protein diet (LP), and a low-protein diet supplemented with 1000 g/t AKG (AKG). Fecal samples were collected on days 40–42 to determine the apparent digestibility of nutrients. The results showed that the feed conversion rate (FCR) in LP-group piglets were significantly higher than that of the CT group (p = 0.028), while the crude protein (CP) digestibility was significantly lower in the LP group compared with the CT group (p = 0.038). However, supplementing the low-protein diet with 1000 g/t AKG effectively mitigated these negative effects. Pigs in the AKG group had reduced incidence of diarrhea between days 1 and 14 compared to CT group (p = 0.041). These findings suggest that incorporating 1000 g/t AKG into low-protein diets may reduce post-weaning diarrhea and improve growth performance of piglets.