Gang Jia

Rapeseed meal (RSM) is a promising protein ingredient for animal feed; however, its utilization is limited by poor digestibility and the presence of anti-nutritional factors. In this study, we first investigated the effects of extrusion and fermentation on the structural characteristics and chemical composition of RSM. Subsequently, 18 growing pigs (6 pigs per treatment, 1 pig per replicate) were used. In period 1, pigs received diets with 20% RSM or fermented extruded rapeseed meal (FERSM) for nutrient digestibility determination. After a 7-day washout, the same pigs were re-assigned to 30% RSM or FERSM diets (6 pigs per treatment) for amino acid digestibility measurement. The results showed that extrusion combined with fermentation resulted in a more porous and loosened structure of RSM. Compared with RSM, FERSM exhibited a significant reduction in glucosinolate (GLs) content, whereas trichloroacetic acid-soluble protein (TCA-SP) content was significantly increased (p_adj < 0.001). Furthermore, pigs fed the FERSM diet showed significantly higher standardized ileal digestibility (SID) and standardized ileal digestible content of methionine (Met) than those fed the RSM diet (p_adj < 0.05). In conclusion, extrusion combined with fermentation, when wheat bran was included in the substrate, effectively modified the physicochemical properties and chemical composition of RSM and was associated with improved Met utilization in growing pigs.

Paddy, as a potential energy feed substitute for maize, is subject to toxin accumulation and nutrient decline during long-term storage, while enzyme-assisted co-fermentation technology can effectively alleviate these adverse changes. This work aimed to evaluate changes in the physical and chemical properties of aged paddy (AP) before and after co-fermentation, and to investigate its effects on nutrient utilization, growth performance, meat quality, digestive function, and cecal microbial composition in meat ducks. Exp.1 was a metabolic trial that evaluated the apparent digestibility of nutrients and the ileal amino acid digestibility of AP subjected to different treatments. Exp.2 utilized 240 Cherry Valley meat ducks (14 days old, 582.29 ± 5.11 g) were assigned to three groups: control (CON) group, a group in which 60% of the corn was replaced with AP, and a group in which 60% of the corn was replaced with fermented and enzymatically hydrolyzed aged paddy (FEAP), with 8 replicates per treatment, with 10 ducks per replicate. Results showed that co-fermentation significantly increased CP, acid-soluble protein, reducing sugar and AA contents of AP, reduced neutral detergent fiber and degraded mycotoxins including deoxynivalenol, aflatoxin B1 and zearalenone (P < 0.005). AP markedly decreased the apparent digestibility of nutrients, GE and ileal AA digestibility in meat ducks, whereas these parameters were significantly restored in the FEAP group (P < 0.05). The FEAP group exhibited higher ADFI and ADG (P < 0.01) along with lower F/G ratio than CON and AP (P = 0.004). FEAP improved meat quality by reducing shear force and drip loss in the breast muscle (P < 0.001), and similar improvements were observed in the leg muscle. Additionally, FEAP increased serum aspartate aminotransferase, alanine aminotransferase, high-density lipoprotein cholesterol, and total cholesterol (P < 0.05). Meanwhile, FEAP enhanced duodenal amylase and trypsin activities (P < 0.01), elevated cecal butyric acid concentration (P = 0.034), and reshaped cecal microbiota structure by increasing the relative abundance of Bacteroides enriching VFAs-producing bacteria. Additionally, Bacteroides abundance was positively correlated with cecal butyric acid (R = 0.59, P = 0.01), while Streptococcus showed a negative correlation (R = -0.74, P = 0.008). In conclusion, co-fermentation has altered the physicochemical properties of AP, thereby enhancing its feed value, improving nutrient utilization, AME, and AA utilization in meat ducks. Replacing 60% dietary corn with FEAP enhances growth performance, meat quality, and digestive function, indicating FEAP is a promising alternative energy feed stuff for meat ducks.

Rapeseed meal (RSM) is an important protein source in animal feed, but its high levels of anti-nutritional factors and crude fiber (CF) limit its utilization in pigs. Our study compared the morphological structure, nutrient composition, and anti-nutritional factors of RSM, extruded rapeseed meal (ERM), and extruded solid-state enzymatically hydrolyzed rapeseed meal (EERM), and evaluated their digestibility in growing pigs. The results showed that ERM and EERM increased surface porosity. Notably, ERM and EERM had higher trichloroacetic acid-soluble protein contents and lower fiber, glucosinolate (GL), and isothiocyanate (ITC) contents. Compared to RSM, the in vitro digestibility of crude protein (CP) was significantly lower in ERM (p < 0.05), whereas EERM exhibited significantly higher digestibility of CP than ERM (p < 0.05). Additionally, compared to RSM and ERM, the digestibility of dry matter (DM) and gross energy (GE) increased significantly in EERM (p < 0.05). For in vivo digestibility, compared to ERM, the digestibility of CP and GE increased significantly in EERM (p < 0.05). In conclusion, our study demonstrates that ERM and EERM can change the chemical composition of RSM, and improve the digestibility of nutrients in pig production.

Background: The fact that feeding pigs with probiotic-fermented agricultural by-products improves pork quality has been repeatedly demonstrated and widely applied, but the underlying mechanisms remain unclear. This study explored the effects of fermented extruded brewers’ spent grain (FEBSG) on meat quality in growing-finishing pigs, as well as its regulatory mechanisms. Methods: Sixty Duroc × Landrace × Yorkshire pigs (52.25 ± 2.10 kg) were randomly assigned to five dietary treatments, in which FEBSG replaced 0, 5%, 10%, 15%, and 20% of soybean meal (SBM). The experiment spanned 10 weeks. Results: Compared with the control, 20% FEBSG significantly increased final body weight, average daily feed intake, and average daily gain, while decreasing feed to gain ratio ( P < 0.05). Both 15% and 20% FEBSG improved carcass characteristics and meat quality, including higher carcass weight, loin eye area, and intramuscular fat content, along with lower drip loss and shear force ( P < 0.05). These treatments also enhanced flavor-related amino acids and unsaturated fatty acids ( P < 0.05), and improved umami and sweet taste profiles. Moreover, 20% FEBSG increased muscle fiber density and reduced fiber diameter, upregulated MyHC I , MyHC IIa , PGC-1α , AMPKα1 , TFAM , and SDH activity, and downregulated MyHC IIb and LDH activity ( P < 0.05). Proteomic analysis identified 69 differentially expressed proteins, with enrichment in AMPK and PPAR signaling pathways. Metagenomic analysis revealed increased abundance of short-chain fatty acid-producing bacteria, including Clostridium , Lactobacillus , Prevotella , and Bartonella . Correlation analysis demonstrated associations between gut microbiota diversity and meat quality traits, as well as between dominant microbial genera and differentially expressed proteins, volatile fatty acids, muscle fiber characteristics, and the AMPK/PGC-1α/TFAM signaling pathway. Conclusions: Partial replacement of SBM with FEBSG positively influenced growth performance and pork quality in pigs, with the underlying mechanisms may involve the activation of the AMPK/PGC-1α/TFAM signaling pathway via the gut-muscle axis, thereby enhancing mitochondrial biogenesis, muscle development, and metabolism.

Intestinal inflammation poses a significant challenge to pig production, as it impairs gut health, compromises growth performance, and results in substantial economic losses. Therefore, preventing and controlling intestinal inflammation in pigs is essential for maintaining intestinal health and production efficiency. Short-chain fatty acids (SCFAs) are gut microbiota metabolites that play an important role in alleviating intestinal inflammation by regulating macrophage function. Mechanistic insights largely derived from murine and in vitro studies have revealed that SCFAs regulate macrophage mediated inflammation through mechanisms involving histone deacetylases (HDACs), nuclear factor-κB (NF-κB), and other pathways. Moreover, nutritional strategies such as dietary fiber, prebiotics, and fermented feed for alleviating intestinal inflammation in pigs are discussed. This review aims to provide a theoretical foundation for developing SCFA-based nutritional interventions to improve gut health, immune regulation, and production performance in pigs.

Ophiopogon japonicus (O. japonicus) by-products contain abundant nutrients and bioactive substances. In this study, we evaluated their effects on production performance and intestinal health in meat rabbits. Firstly, we measured the nutrient levels of O. japonicus by-products along with its digestibility in meat rabbits. Then, we replaced dietary alfalfa meal with O. japonicus by-products to evaluate its effects on growth performance, carcass traits, apparent digestibility, and intestinal immunity in meat rabbits. The results showed that the effects of O. japonicus by-products on growing meat rabbits varied over time. In the early phase (days 1–21), it significantly depressed average daily gain (ADG, p < 0.001) and average daily feed intake (ADFI, p < 0.001), and increased feed to gain ratio (F:G) (p < 0.001). However, in the later phase (days 22–35), a compensatory response emerged, with significantly increased ADG (p < 0.001) and reduced ADFI (p < 0.01) and F:G (p < 0.001). Despite this compensatory growth, the growth performance and feed efficiency for the entire experimental period were not improved. O. japonicus by-products decreased carcass weight significantly (p < 0.001), but did not significantly affect dressing percentage and meat traits (p > 0.05), while it significantly reduced the digestibility of crude protein (CP, p < 0.05), increased that of crude fiber (CF, p < 0.001), and reduced the activities of amylase (p < 0.01) and increased trypsin in cecal contents (p < 0.05). Additionally, O. japonicus by-products elevated the levels of secretory immunoglobulin A (sIgA) and interleukin-10 (IL-10) in ileal mucosa (p < 0.05). They did not significantly affect the cecal microbial community or short chain fatty acid (SCFA) levels (p > 0.05). Our research indicated that O. japonicus by-products possess a balanced nutritional composition and improve intestinal immunity in rabbit production, making them a viable feed ingredient to partially replace alfalfa meal.

This study evaluated the effects of dietary distillers' dried grains with solubles (DDGS) levels on nutrient digestibility, meat quality, and intestinal health in meat ducks. In a 28-d feeding trial (Exp. 1), 400 Cherry Valley ducks (average body weight [BW] = 658.73 ± 3.79 g, age = 14 d old) were randomly assigned to five groups receiving 0 (CON), 5%, 10%, 15%, or 20% DDGS. Each treatment had eight replicates (cages) with ten ducks per replicate. A subsequent metabolism trial (Exp. 2) was conducted using the same diets. At 42 d of age, two ducks per replicate were randomly selected and fed diets supplemented with 0.5% titanium dioxide for digestibility determination. Results showed that 20% DDGS significantly reduced the digestibility of gross energy (GE; P = 0.010) and crude protein (CP; P = 0.026) compared to the CON group. As DDGS increased, CP digestibility decreased linearly (P = 0.001) and quadratically (P = 0.049). Serum triglyceride levels were significantly increased in the 20% DDGS group (P = 0.034). For meat quality, DDGS decreased breast muscle lightness (L∗_{45 min}, P = 0.031) and increased yellowness (b∗_{45 min}, P = 0.028). Shear force of breast muscle increased significantly in the 20% DDGS group (P = 0.009) and increased linearly with DDGS (P = 0.015). Histologically, DDGS supplementation decreased muscle fiber density (P = 0.005) and jejunal villus height (P = 0.001), but increased muscle fiber diameter (P = 0.027). Both muscle fiber diameter and density showed significant linear relationships with increasing DDGS levels (P = 0.003 and P < 0.001, respectively). Cecal butyric acid level decreased at 15% and 20% inclusion (P < 0.05), and valeric acid level decreased at 20% inclusion (P < 0.001). Notably, 10% DDGS increased cecal microbial diversity and the abundance of beneficial Prevotellaceae (P < 0.05). In summary, dietary inclusion of 5%–20% DDGS did not adversely affect growth performance, carcass traits, and organ indices in ducks. While higher levels impaired some meat quality traits, 10% DDGS was identified as the optimal level, improving intestinal microbiota without compromising overall production performance. These findings support the partial replacement of corn-soybean meal with DDGS in duck diets.

Hydroxymethionine manganese (MnHMet), as a novel organic trace element additive, has demonstrated significant effects on improving meat quality, enhancing antioxidant capacity, and lipid metabolism. However, its specific effects on Cherry Valley ducks remain unclear. This study explored the effects of dietary MnHMet on meat quality, antioxidant capacity, and lipid metabolism in meat ducks. In a 35-day study, 560 1-day-old male ducks were randomly assigned to seven groups: six groups were supplemented MnHMet at 0, 30, 60, 90, 120, and 150 mg/kg, and a group was supplemented 120 mg/kg MnSO₄. Results showed that the 120 mg/kg MnHMet group had significantly lower triglyceride (TG) levels than the MnSO₄ group (P < 0.05). Serum high-density lipoprotein cholesterol levels increased significantly in the MnHMet groups compared to the 0 mg/kg group and showed a quadratic change to increasing MnHMet levels (P < 0.05). MnHMet supplementation reduced drip loss, shear force, abdominal fat weight, and percentage while increasing intramuscular fat (IMF, P < 0.05). Drip loss and shear force decreased linearly, and IMF showed a quadratic response to MnHMet levels (P < 0.05). Fatty acid analysis revealed a quadratic decrease in hepatic C23:0 concentrations (P < 0.05). MnHMet improved antioxidant capacity by enhancing total antioxidant capacity (T-AOC), upregulating MnSOD mRNA expression in the liver and breast muscle, increasing hepatic MnSOD levels, and reducing malondialdehyde (MDA) levels (P < 0.05). T-AOC levels exhibited quadratic and linear increases in breast muscle and liver, respectively, while hepatic MDA levels decreased quadratically (P < 0.05). Catalase levels in breast muscle were significantly higher in the MnHMet group than in the MnSO₄ group (P < 0.05). Additionally, MnHMet reduced adipocyte area, downregulated hepatic fatty acid synthase and acetyl-CoA carboxylase, and upregulated peroxisome proliferator-activated receptor-γ, carnitine palmitoyltransferase-1α, and lipoprotein lipase (P < 0.05). Based on IMF and abdominal fat percentage, the optimal MnHMet supplementation levels were 107.5 and 117.5 mg/kg, respectively. These results revealed that MnHMet supplementation improved muscle mass, fatty acid composition, reduced abdominal fat, and enhanced meat quality by regulating antioxidant capacity and lipid metabolism in meat ducks.