Dietary lipid supplementation improves sow reproductive performance, survival, and growth of piglets. This study was conducted to investigate the effects of maternal fatty acid-balanced oil (FABO) supplementation during late gestation and lactation on the reproductive performance of sows, and the growth performance and intestinal barrier function of their offspring. Twenty-four multiparous sows (Landrace × Large White) with similar parity (2.29 ± 0.25), body weight (BW; 223.60 ± 11.32 kg) and backfat (BF) thickness (17.10 ± 2.03 mm) were divided into 2 treatment groups (n = 12). The sows were fed with a basal diet supplemented with either 2% soybean oil (2% SO) or 2% fatty acid-balanced oil (2% FABO) from d 90 of gestation to the end of lactation (d 21 postpartum). At d 21 postpartum, 24 piglets (one per litter, 5.32 ± 0.07 kg BW, six per group) were assigned to a 2 × 2 factorial arrangement of treatments (2% SO vs. 2% FABO) and lipopolysaccharide (LPS) challenge (saline vs. LPS). Within each maternal diet group, half of the piglets were injected intraperitoneally with either 100 μg/kg BW LPS or saline. At 4 h post-injection, all piglets were slaughtered and intestinal samples were collected. Maternal 2% FABO supplementation increased the piglet weight at birth and litter weight at weaning (P < 0.05), and tended to enhance weaning survivability (P = 0.076). Moreover, piglets born to sows supplemented with 2% FABO exhibited higher litter weight gain and average daily gain compared to those from sows receiving 2% SO diet (P < 0.05). The 2% FABO increased colostral protein, immunoglobin (Ig) G, IgM and IgA concentrations (P < 0.05). Piglets suckling 2% FABO-supplemented sows exhibited greater villus height and maltase and sucrase activities in the jejunum (P < 0.05). Maternal dietary 2% FABO supplementation fortified intestinal barrier function, as evidenced by elevated goblet cell number and intestinal tight junction protein claudin-1 and ZO-1 expression, as well as mRNA abundance of pBD-3 and secretory immunoglobulin A (sIgA) concentration in the jejunum of piglets (P < 0.05). Piglets suckling 2% FABO-supplemented sows had lower mRNA abundance of HSP-70 and higher IL-10 mRNA abundance in the jejunum (P < 0.05). Sow dietary 2% FABO supplementation elevated the IL-22/STAT3 pathway key factors JAK1, TYK2 and STAT3 mRNA abundance, and IL-22, p-STAT3 protein expression and p-STAT3:t-STAT3 ratio in the jejunum of piglets (P < 0.05). In conclusion, maternal supplementation with 2% FABO increased IgG, IgM and IgA concentrations in colostrum, and improved growth performance of offspring. Moreover, maternal dietary 2% FABO supplementation fortified intestinal barrier function of offspring, likely through modulation of the IL-22/STAT3 signaling pathway.
Research on animal nutrition, including the impact of diets on immune system development and function, continues to expand our understanding of nutritional immunology to improve animal health and performance. From the perspective of research conducted in mammalian and avian immunology, this manuscript highlights species-appropriate approaches for performing immune assessments in experimental animals. Emphasis is placed on the importance of basic immunology knowledge, attention to detail to avoid flawed experiments, and precision in reporting and interpreting results to avoid incorrect conclusions and health recommendations. Animal nutritionists who incorporate immunological approaches into their research must use standardized procedures, validated tools, appropriate controls, and collaborate closely with immunologists to gather valid, reliable immunological insights from their studies. Topics addressed include the uses of peripheral blood analysis as a window into systemic immune system activities, along with methodological approaches ranging from establishing profiles of circulating leukocyte populations to leukocyte isolation methods and commonly used procedures to gain insight into their functional capabilities. By highlighting the differences in mammalian and avian procedures, researchers will also be made aware of potential pitfalls when working with other animal species. For example, white blood cells in birds and fish also include thrombocytes that may make up the majority of white blood cells but are not considered part of the immune cell populations (lymphocytes, neutrophils [heterophils in birds], monocytes, eosinophils, and basophils) in the blood. The methodologies described for blood are also applicable to immune system-related studies in tissues (e.g., lymphoid organs and sites of inflammation, etc.), including establishment of leukocyte profiles and leukocyte isolation for in vitro assessment. In addition to in vitro assays, methodologies to assess cell-mediated immunity in vivo are addressed. These include using the skin as a window into responses taking place in a complex tissue. Among characteristic skin swelling responses following intradermal injection of antigens or immunostimulants, the unique in vivo growing feather pulp bioassay in poultry is highlighted, as it is a minimally invasive procedure that enables assessment of local tissue/cellular immune responses across time in an individual without invasive surgical procedure or euthanization of the birds. Overall, the objective is to assist nutritionists and animal health researchers in implementing and integrating scientifically sound immunological approaches and considerations in research studies to acquire important insights that will further expand knowledge in nutritional immunology.
Short-chain fatty acids (SCFA), mainly acetate, propionate, and butyrate, are produced by anaerobic microbial fermentation of indigestible dietary components in the animal gut. These metabolites are important energy substrates, yet their influence extends well beyond energy supply to gut and systemic homeostasis. This review summarizes the production, transport, and physiological roles of SCFA in gastrointestinal health. Short-chain fatty acids are produced by anaerobic microbial fermentation, but their major substrates and sites of production differ between monogastric and ruminant animals. In monogastric animals, SCFA originate primarily from hindgut fermentation of dietary fiber, whereas in ruminants, microbial breakdown of feed carbohydrates in the rumen is the dominant source. Their absorption and transport rely on passive diffusion and carrier-mediated mechanisms involving monocarboxylate transporters (MCT), sodium-coupled monocarboxylate transporters (SMCT), and anion exchangers. Within the intestinal mucosa, SCFA regulate energy metabolism, epithelial barrier integrity, microbial composition, and immune homeostasis. Their molecular targets include G protein-coupled receptors (GPCR) and AMP-activated protein kinase (AMPK), they also inhibit histone deacetylases (HDAC). These signals feed into downstream cascades along the mitogen-activated protein kinase (MAPK), mammalian target of rapamycin-signal transducer and activator of transcription 3 (mTOR–STAT3), and nuclear factor kappa-B (NF-κB) pathways. Through these mechanisms, SCFA strengthen tight junction assembly, stimulate the secretion of mucin and defensins, suppress pathogen expansion, and promote colonization of beneficial microbiota. They also promote the differentiation of regulatory T cells (Treg) and the production of anti-inflammatory cytokines, helping maintain mucosal immune balance. In conclusion, SCFA act concurrently as metabolic intermediates, epigenetic modulators, and immune mediators, coupling microbial fermentation to host physiology. Understanding their multifaceted actions offers novel insights into nutritional strategies and microbial modulation to improve gastrointestinal health and productivity in animals.
Accurate quantification of endogenous amino acid losses (EAAL) is fundamental for determining the true digestibility (TD) of feed ingredients. This study aimed to investigate whether the 15N-leucine single injection method (SIM) could be used to determine EAAL, measure the TD of different protein sources using this method, and provide a basis for the application of low-protein diets in poultry. In Exp. 1, 21 cecectomized Jingfen roosters (21-wk-old, body weight [BW] 1.54 ± 0.01 kg) were assigned to three treatments with nitrogen-free diet (NFD) group, continuous infusion method (CIM)-CON group, and SIM-CON group, with the latter two groups receiving a standard diet. The experiment was conducted over a 12-d period, with seven replicates per treatment and one bird per replicate. In Exp. 2, 35 cecectomized Jingfen roosters (40-wk-old; BW 1.69 ± 0.04 kg) were allocated to five dietary treatments with soybean meal (SBM) diet, cottonseed meal (CSM) diet, rapeseed meal (RSM) diet, a mixed diet (with protein provided jointly by SBM, CSM, and RSM), and a NDF diet. Each treatment consisted of seven replicates with one bird per replicate, and the experimental period lasted for 4 d. In Exp. 3, 384 one-day-old Arbor Acres broilers (BW 41.06 ± 0.11 g) were distributed into 4 dietary treatment groups, with eight replicates per treatment and 12 birds per replicate. The experimental period lasted for 42 d. The four treatments consisted of diets formulated based on either standard ileal digestibility (SID) or total TD values, at either normal (CON) or low-protein diet (LPD), designated as SID-CON, TD-CON, SID-LPD, and TD-LPD, respectively. In Exp. 1, SIM yielded EAAL and TD values comparable to the CIM (P > 0.05); except for isoleucine, phenylalanine and cysteine, estimates from the two isotope methods were significantly higher than the NFD method (P < 0.05). In Exp. 2, with the exception of proline, the TD values determined for mixed diets did not differ significantly from the predicted values derived from single ingredients (P > 0.05), confirming the additivity of SIM-derived TD values. In Exp. 3, broilers fed TD-CON diets exhibited significantly lower feed: gain ratio (F: G) and reduced specific EAAL (e.g., arginine and lysine) during the starter phase (1–21 d) compared to the SID-CON group (P < 0.05). In conclusion, this study demonstrated that SIM is a reliable technique for determining EAAL and TD in poultry. Relative to traditional SID-based systems, feed formulations using SIM can improve broiler feed efficiency while reducing SBM inclusion.
Dietary lysine levels during the finishing stage are known to influence meat quality in pigs, but the long-term effects of maternal lysine intake during pregnancy remain unclear. In this study, 120 primiparous Landrace × Large White sows (initial body weight, 135.48 ± 1.07 kg; age, 230 ± 5 d) were randomly assigned on d 1 of gestation to three dietary treatments (40 replicates per treatment, with one sow per replicate) and fed diets containing 0.51%, 0.77%, or 1.03% lysine throughout gestation. Approximately 60 offspring per treatment were monitored from birth to the finishing stage (160 d of age), and six offspring from the same six selected litters per treatment were sampled at each stage for muscle development and meat quality evaluations. No significant differences were observed in average daily gain among the three groups (P > 0.05), Compared with the 1.03% group, offspring from the 0.51% group exhibited higher marbling scores and IMF content (P < 0.05). Although shear force did not differ significantly among the three groups (P > 0.05), it increased linearly with increasing maternal dietary lysine levels (P = 0.048). Compared with the 1.03% group, the 0.51% group showed higher FATP4 protein expression at both stages and higher CD36 and PPARγ protein expression only in finishing pigs, whereas PPARγ protein expression in newborn piglets was higher in the 0.77% group (P < 0.05). In addition, the 0.51% group promoted a shift toward slow oxidative fibers, with higher slow-MyHC protein expression at both stages (P < 0.05); this group also showed higher MYH1 and lower MYH4 gene expression in newborn piglets and lower fast-MyHC protein expression in finishing pigs (P < 0.05); in newborn piglets, this shift was associated with activation of the AMP-activated protein kinase (AMPK) signaling pathway and upregulation of TFAM, TFB1M, CYTC, and CS, whereas only TFB1M and CS were upregulated in finishing pigs (P < 0.05). In contrast, the 0.77% group showed enhanced expression of muscle development markers (MYF5 and MYOG) (P < 0.05) and activation of mTOR signaling in newborn piglets, although these effects were not maintained during the finishing stage. Correlation analysis further demonstrated that early-life lipid metabolism and muscle fiber characteristics were closely associated with meat quality traits in finishing pigs. Collectively, maternal lysine levels during gestation exert long-term effects on offspring meat quality by regulating IMF deposition and muscle fiber type composition.
Disorders of hepatic glucose and lipid metabolism are a significant factor reducing the economic value of largemouth bass. Ursolic acid (UA) has been shown to regulate such metabolic disorders. This study aimed to investigate the core mechanism of UA in hepatic glucose and lipid metabolism in largemouth bass fed a high starch (HS) diet. A total of 800 healthy largemouth bass with an initial average body weight of 11.00 ± 0.12 g were selected and randomly allocated into four treatment groups in a 2 × 2 factorial design: control (CON) group, UA group, HS group, and HS + UA group. Each group had five replicates with 40 fish per replicate. Fish in the CON group received a basal diet (7.38% starch); the UA group received the basal diet supplemented with UA at 500 mg/kg; the HS group received the HS diet (13.26% starch); and the HS + UA group received the HS diet supplemented with UA at 500 mg/kg. The experiment lasted for 8 weeks. To further validate the direct regulatory effect of UA on the CERK/PI3K/AKT signaling pathway in hepatocytes, this study established an in vitro primary hepatocyte culture model containing five groups: CON, high-glucose (HG), HG + UA, HG + NVP231 (CERK inhibitor), and HG + UA + NVP231. Results showed that the HS diet led to reduced final weight, weight gain ratio and body crude protein content, increased body ether extract content and hepatic collagen area (P < 0.05), while UA intervention reversed these adverse changes in bass (P < 0.05). Transcriptomic sequencing identified cerk and b4galnt1b as key genes regulating hepatic glucose and lipid metabolism, enriched in the glycosphingolipid biosynthesis-ganglio series pathway. Compared with the CON group, hepatic b4galnt1b expression was decreased, while cerk expression was increased in the HS group, and these expression trends were reversed by UA treatment (P < 0.05). Furthermore, UA increased hepatic p-PI3K and p-AKT1 protein levels, and reduced serum triacylglycerol and cholesterol contents (P < 0.05), while improved serum insulin contents, and hepatic phosphofructokinase (PFK) activity (P < 0.05). It also down-regulated hepatic il-1β and tnf-α expression and up-regulated il-10 expression (P < 0.05). In vitro experiments showed that 25 mmol/L glucose induction enhanced cell viability but increased triacylglycerol content and phosphoenolpyruvate carboxykinase activity while decreasing PFK activity (P < 0.05). Treatment with 1 μmol/L UA further improved cell viability, ameliorated these metabolic indicators, and enhanced p-AKT1, AKT1, and p-PI3K protein expression (P < 0.05). The CERK inhibitor NVP231 was applied, the expression of p-PI3K, p-AKT1, and AKT1 was suppressed (P < 0.05), and UA could no longer activate this pathway under HG conditions. In summary, the UA alleviates HS induced hepatic glucose and lipid metabolism disorders in largemouth bass main via the CERK/PI3K/AKT signaling pathway.
This study aimed to investigate the effects of low-protein (LP) diet with double-low rapeseed meal (DLR) partially replacing soybean meal (SBM) on the growth performance, meat quality, and nitrogen excretion of Cherry Valley ducks. In a randomized complete block design, a total of 504 one-day-old Cherry Valley ducks with consistent health, weight, and genetic background (body weight = 51.80 ± 1.49 g) were randomly assigned to seven groups (six replicates/group, 12 ducks/replicate). The dietary crude protein (CP) level was reduced in 0.5 percentage point increments, with the amino acid and energy balance maintained. The dietary CP levels were 20.01% (CON), 19.51%, 19.01%, 18.51%, 18.01%, 17.51%, and 17.01% (LP1, LP2, LP3, LP4, LP5, and LP6, respectively) for 1-14 d of age, 17.50% (CON), 17.00%, 16.50%, 16.00%, 15.50%, 15.00%, and 14.50% (LP1, LP2, LP3, LP4, LP5, and LP6, respectively) for 15-42 d of age. The results showed that dietary treatment significantly affected feed conversion ratio (FCR) (P < 0.05), but no linear or quadratic trends were observed (P > 0.05); blood urea nitrogen (BUN) content in the grower phase changed significantly (P < 0.05); abdominal fat yield (AFY) increased linearly (P = 0.002); meat color parameters (lightness [L*], redness [a*], and yellowness [b*]) were significantly altered, showing both linear and quadratic trends (P < 0.05); and among meat quality traits, only shear force was significantly affected, also displaying linear and quadratic trends (P < 0.05). The LP diet improved the structure of the intestinal microbiota and significantly reduced nitrogen excretion (P < 0.05). In conclusion, reducing the dietary CP level by 2 percentage points was the optimal strategy, as it maintained growth performance while reducing nitrogen pollution, provided theoretical basis and practical guidance for the design of LP diet in the poultry industry, and contributed to the goal of cost reduction and efficiency improvement in China’s livestock and poultry production.
Fatty liver syndrome (FLS) in aged laying hens is characterized by excessive hepatic lipid accumulation and impaired performance. This study evaluated the effects of dietary supplementation with a porcine bile-derived bile acid (BA) product (containing 19.9% goose-derived deoxycholic acid and 77.2% porcine BAs) on hepatic lipid dysregulation and the development of FLS in aged laying hens fed a high-energy low-protein (HELP) diet. A total of 384 Hy-Line Brown laying hens (75 week of age, baseline laying rate approximately 72%) were randomly allocated to a 2 × 2 factorial arrangement with four dietary treatments: a control diet (11.29 MJ/kg metabolizable energy [ME], 16.5% crude protein [CP]) or a HELP diet (12.56 MJ/kg ME, 13.0% CP), each supplemented with or without 100 mg/kg BAs. The experiment was conducted over the late laying period, and data were analyzed using a two-way ANOVA to assess the main effects of diet, BA supplementation, and their interaction. Compared with the HELP group, the HELP + BAs group exhibited significantly improved laying performance, as evidenced by increased egg production, enhanced feed efficiency, and higher eggshell density (P < 0.05). In the liver, a significant interaction between HELP diet and BAs supplementation was observed (P < 0.05). Compared with the HELP group, the HELP + BAs group also showed a significant reduction in hepatic lipid accumulation, as evidenced by decreased lipid droplet deposition and lower hepatic triglyceride and total cholesterol levels (P < 0.05). Moreover, BAs increased hepatic carnitine palmitoyltransferase-1 (CPT1) activity while suppressing fatty acid synthase (FAS) activity and this also involved interactions (P < 0.05). Gene expression analysis showed that, compared with the group without BAs supplementation, BA supplementation downregulated the key lipogenic genes (FASN and ACC), with a significant interaction observed between the HELP diet and BA supplementation (P < 0.05). In addition, BA supplementation regulated the expression of genes involved in BA and lipid metabolism (PPARγ, LRH-1, and CYP7A1) (P < 0.05). In addition, BA supplementation enhanced hepatic protein expression of p-AMPK and p-ACC (P < 0.05). Taken together, these results suggest that dietary BA supplementation effectively alleviates HELP-induced FLS in aged laying hens by inhibiting hepatic lipogenesis and promoting fatty acid oxidation. This effect is likely to improve both liver health and egg production performance.
This study evaluated the effects of graded dietary supplementation with yellow mealworm (Tenebrio molitor, TM) larvae meal on laying performance, egg quality characteristics, and cecal microbiota in laying hens. A total of 360 Hy-Line White hens (34 weeks old; 1.54 ± 0.08 kg) were assigned to five dietary treatments (0 [CON], 2% [TM2], 4% [TM4], 6% [TM6], and 8% TM larvae meal [TM8]) for 70 d, with six replicates per treatment and 12 hens per replicate. Supplementation with TM larvae meal did not affect laying rate or feed conversion ratio (P > 0.05). In terms of egg nutritional composition, diets containing 4%-8% TM larvae meal significantly increased total amino acid and essential amino acid contents compared with the CON (P < 0.05), with significant increases in tyrosine, valine, cystine, aspartic acid, and glutamic acid (except for TM4 group) contents (P < 0.05). While total polyunsaturated fatty acids (PUFA) content remained unchanged (P > 0.05), supplemental TM larvae meal in diets increased the contents of saturated fatty acids and monounsaturated fatty acids in both linear and quadratic fashions (P < 0.05). The ω-6/ω-3 PUFA ratio also increased linearly (P = 0.003) and quadratically (P = 0.015). However, the 4% TM larvae meal diet maintained a ratio comparable to the CON (P > 0.05); whereas higher inclusion levels significantly elevated this ratio (P = 0.027). Electronic nose analysis revealed dose-dependent reductions in off-odor compounds (P < 0.05), while texture analysis showed increased yolk chewiness and cohesiveness in the TM4, TM6, and TM8 groups compared with the CON group (P < 0.05). Dietary TM larvae meal supplementation also enhanced antioxidant capacity, as reflected by increased serum total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities and reduced egg malondialdehyde (MDA) levels in the TM4, TM6, and TM8 groups when compared with CON (P < 0.05). Cecal microbiota profiling indicated dose-dependent enrichment of specific genera, including Butyricimonas (P = 0.013). Correlation analysis showed that the relative abundance of Colidextribacter and Butyricimonas were positively associated with serum antioxidant indices and negatively correlated with egg MDA levels (P < 0.05). In conclusion, a 4% TM larvae meal inclusion level enhances egg amino acid profiles, sensory traits, and antioxidant capacity without compromising performance or the yolk ω-6/ω-3 PUFA ratio.
Sunflower oilcake (SF) has limited use in aquafeeds due to its high fibre content and anti-nutritional factors. Microbial solid-state fermentation (SSF) can mitigate these limitations while enhancing nutritional and functional value. This study evaluated the potential of microbial fermented sunflower oilcake (FSF) in diets for Pacific white shrimp (Penaeus vannamei). Commercial SF was fermented using Bacillus subtilis (1 × 109 CFU/mL) and Saccharomyces cerevisiae (1 × 108 CFU/mL) at 34 °C in a pilot-scale fermenter. A total of 180 iuvenile shrimp (1.86 ± 0.01 g) were fed three isonitrogenous diets: a control diet (CON), a diet with 2.5% raw sunflower oilcake (SF-2.5), and a diet with 2.5% fermented sunflower oilcake (FSF-2.5) for 56 d. Feed analysis indicated that fermentation increased crude protein and essential amino acid contents, while reducing fibre and antinutritional factors such as tannins and saponins. Shrimp fed the FSF-2.5 diet showed significantly higher weight gain and daily growth coefficient (DGC), and a lower feed conversion ratio (FCR) compared to other dietary groups (P < 0.05). Protease and amylase activities were significantly higher in the FSF-2.5 group, followed by CON and SF-2.5 (P = 0.001). Superoxide dismutase (SOD) and phenoloxidase (PO) activities were also significantly higher in shrimp fed the FSF-2.5 diet (P < 0.05). Histological examination revealed that the FSF-2.5 group exhibited normal hepatopancreatic architecture with intact tubules and an adequate presence of blister-like, fibrillar, and resorptive cells. Gut microbiota analysis using 16S rRNA sequencing revealed that shrimp fed the CON diet had the highest number of unique amplicon sequence variants (ASVs; 3116), followed by FSF-2.5 (2684) and SF-2.5 (1430). The FSF-2.5 diet increased the relative abundance of potential beneficial bacterial groups, such as Fulvivirga, Ruegeria, and Shimia, while reducing the pathogenic Pseudomonas in the shrimp gut (P < 0.05). Differential abundance analysis of ASVs using analysis of compositions of microbiomes with bias correction (ANCOM-BC) from QIIME2 plugin revealed enrichment of beneficial Micrococcus and Staphylococcus in the FSF-2.5 group compared to SF-2.5. These findings demonstrate that FSF functions beyond its nutritional role, acting as a gut health promoter, and can be considered as a sustainable functional feed ingredient for shrimp aquaculture.
Phosphatidylinositol (PI) is an important phospholipid involved in membrane structure, lipid transport, and cellular signaling, but its nutritional role in regulating ovarian maturation in crustacean broodstock remains poorly understood. To elucidate the effects and mechanisms by which dietary PI modulates ovarian development in female broodstock of Pacific white shrimp (Penaeus vannamei), five isonitrogenous, isolipidic, and semi-purified diets containing 0.0, 0.2%, 0.4%, 0.6%, or 0.8% PI (dry-matter basis) were formulated and fed to shrimp for 28 d. A total of 160 seven-month-old females (initial body weight 39.70 ± 1.80 g) at ovarian stage I were allocated to five treatments with four replicates each and eight shrimp per replicate. Compared with the control group (0.0 PI), the 0.6% PI diet significantly increased the gonadosomatic index (P < 0.001) and reduced the hepatosomatic index (P = 0.030) and shortened each of the ovarian stages I–III by approximately two days (stage I, P = 0.056; stage II, P = 0.159; stage III, P = 0.007). Mean oocyte area in the ovary (P < 0.001) and lipid-droplet area in the hepatopancreas (P < 0.001) were both greatest in the 0.6% PI group compared with the other dietary groups. Ovarian total cholesterol was highest in the 0.6% group (P = 0.029). Serum high-density lipoprotein and low-density lipoprotein declined in most PI-supplemented groups, reaching their lowest levels at 0.6% (P < 0.05). Endocrine profiling showed increased estradiol at 0.6% and 0.8% (P < 0.001), elevated progesterone across all supplemented groups (P = 0.007), and reduced molt-inhibiting hormone at 0.2% and 0.6% (P = 0.043). Transcriptomics identified 421 differentially expressed genes enriched for lipid synthesis and transport and for TGF-β/Notch signaling, while metabolomics revealed upregulation of D-sphingosine, palmitic acid, and stearic acid, with decreased levels of purines (guanine and hypoxanthine) and B-vitamin intermediates (riboflavinand and pantothenate). Multi-omics integration indicated potentiation of sphingolipid metabolism and fatty-acid biosynthesis, alongside heightened consumption within purine metabolism, as a potential regulatory pathway promoting ovarian maturation. In summary, dietary PI may facilitate ovarian maturation by coordinating lipid mobilization and steroidogenesis, potentially interacting with developmental signaling pathways. A recommended supplementation range of 0.442%–0.586% (dry-matter basis) is suggested based on dose-response modeling, with 0.6% yielding the significant response. These findings provide new insights into broodstock nutrition strategy in shrimp aquaculture.
The regulation of appetite in livestock and poultry is a complex process that involves the integration of central and peripheral physiological mechanisms. The process is regulated by nutritional, environmental, and genetic factors. This review synthesises current understanding of the neuroendocrine and gut–brain axis pathways that regulate appetite, including hypothalamic signalling via agouti-related protein (AgRP)/neuropeptide Y (NPY) and proopiomelanocortin (POMC)/cocaine- and amphetamine-regulated transcript (CART) neurons, as well as peripheral modulation by gut hormones (e.g., ghrelin, leptin [LEP], and glucagon-like peptide–1 [GLP-1]) and microbial metabolites (e.g., volatile fatty acids [VFA]). Distinct species–specific characteristics, such as the use of rumen fill and VFA of ruminants, visual feed preference in poultry, and taste–driven intake in swine, underline the need to develop proper nutritional strategies. The regulatory and potential mechanism of some important dietary factors, such as energy density, protein and amino acid balance, micronutrients and functional additives (e.g., phytochemicals, probiotics, and acidifiers), are discussed in this paper, which can enhance satiety or stimulate feed intake. Furthermore, the latest advancements in species- and stage-specific nutritional intervention strategies for swine, ruminants, and poultry are summarised. Emerging approaches, including novel alternative feed resources, multi-omics analysis, feed-focused genome editing, and precision feeding systems, offer promising strategies to improve feed efficiency and animal health. Future research should integrate molecular biology, nutrigenomics, and smart farming technologies to develop sustainable, species–specific strategies for appetite modulation, thereby enhancing livestock productivity and welfare.
This study explored the effects of fermented corn germ meal (FCGM) on growth performance, inflammatory response, and intestinal microbiota in broiler chickens. A total of 180 one-d-old AA broilers (initial average body weight of 39.16 ± 0.05 g) were randomly divided into three groups: CON group, basal diet; CGM group, basal diet supplemented with 7% corn germ meal (CGM); FCGM group, basal diet supplemented with 7% FCGM. Each group contained 6 replicates with 10 broilers per replicate. The experimental period lasted for 42 d. Compared with unfermented CGM, fermentation significantly increased the contents of crude protein (CP), lactic acid (LA), acetic acid (AA), and propionic acid (PA) (P < 0.05), while reducing crude fiber (CF) content (P = 0.036). The FCGM had no significant impact on growth performance of broiler chickens (P > 0.05), but significantly increased cecal AA content at 21 and 42 d (P < 0.05). Additionally, FCGM modulated the expression of G protein-coupled receptors (GPCRs) and the mitogen-activated protein kinase (MAPK) signaling pathway in cecal tissue, with downregulated relative mRNA expression of ERK and p38 at d 42, and altered inflammatory status via upregulation of the anti-inflammatory cytokine IL-10 relative mRNA expression at d 21 (P < 0.05). Additionally, FCGM stabilized ileal and cecal microbiota succession. Among these, Firmicutes and Lactobacillus are the dominant bacterial groups, and their abundance showed significant changes over time. Ileal microbiota assembly was dominated by stochastic processes, while cecal microbiota was influenced by both deterministic and stochastic processes. These findings indicate FCGM improves broiler gut health via a metabolite-receptor-microbiota, offering a viable nutritional strategy for antibiotic-free poultry production.
Rising frequencies of summer heatwaves driven by climate change impose severe physiological stress on aquaculture species. This study investigated the effects of dietary taurine supplementation (0.0%, 0.8%, 1.2%, and 2.0%) on the growth, intestinal health, and environmental stress tolerance of Megalobrama amblycephala. Over an 8-week trial conducted under natural temperature fluctuations (26.5‒35.3 °C), 360 fish (initial body weight: 6.47 ± 0.04 g) were randomly allocated into 12 outdoor cages (three replicates per treatment). Taurine supplementation significantly enhanced growth performance, increasing final body weight (FBW), final body length (FBL), weight gain rate (WGR), and specific growth rate (SGR) compared to the control (P < 0.001), while survival rate was unaffected (P > 0.05). Polynomial regression identified 1.460% dietary taurine as the optimal level for maximizing SGR. Whole-body composition analysis revealed that taurine elevated crude protein and reduced ash contents (P < 0.05), with no significant difference in moisture or crude lipid (P > 0.05). Furthermore, taurine improved the muscle amino acid profile, significantly raising the levels of both essential and non-essential amino acids among the 17 amino acids detected (P < 0.05). Taurine supplementation enhanced systemic antioxidant capacity by increasing total antioxidant capacity (T-AOC) and the activities of the key serum antioxidant enzymes (superoxide dismutase [SOD] and catalase [CAT]), reducing malondialdehyde (MDA) and reactive oxygen species (ROS) levels, and activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/ Kelch-like ECH-associated protein 1 (Keap-1)/heme oxygenase-1 (HO-1) pathway (P < 0.05). It also exerted anti-inflammatory effects via suppressing the nuclear factor kappa B (NF-κB) signaling pathway, reducing pro-inflammatory cytokines (il-1β, tnf-α, and il-8) and increasing anti-inflammatory mediators (tgf-β and il-10) (P < 0.05). Intestinal health was improved, as evidenced by increased villus height and muscularis thickness, higher digestive enzyme activities (amylase, lipase, and trypsin), and upregulated mucin-related gene expression (P < 0.05). Finally, taurine supplementation improved the tolerance of M. amblycephala to environmental stress. Although 1.460% taurine maximized SGR, a lower supplementation level of 0.8% provided the best overall performance when considering feed conversion ratio (FCR) and stress tolerance. Therefore, a dietary taurine supplementation of 0.8% is recommended for optimal overall performance, effectively promoting growth, reducing FCR, strengthening antioxidant and anti-inflammatory defenses, supporting intestinal barrier function, and improving climate stress tolerance in M. amblycephala. These findings support the potential practical use of taurine as an ecologically sustainable feed additive that concurrently addresses production performance and climate adaptation in M. amblycephala aquaculture.
Low-protein (LP) diets improve nitrogen utilization efficiency and mitigate environmental pollution, however, excessive reductions in crude protein (CP) result in total nitrogen (TN) deficiency, thereby compromising growth performance. This study investigated the effects of replacing calcium hydrogen phosphate with diammonium phosphate (DP) in an LP diet on growth performance, carcass traits, meat quality, plasma biochemical parameters, hepatic nitrogen-metabolizing enzyme activities, and amino acid (AA) profiles in finishing pigs under TN restriction. Additionally, 15nitroge (15N)-isotope tracing was employed in suckling piglets to track ammonia nitrogen assimilation by analyzing 15N enrichment in plasma and hepatic AA following 15N-DP administration. Sixty-three barrows (Duroc × Landrace × Large White; initial BW: 74.3 ± 3.8 kg) were randomly allocated to one of three dietary treatments: a normal protein (NP) diet (CP 13.47%), a LP diet (CP 9.06%), or a LP (CP 10.47%) diet supplemented with 1.07% DP (LDP). All pigs had ad libitum access to feed and water for 51 d. The ratio of essential AA nitrogen to TN was 0.43, 0.50, and 0.43 in the NP, LP, and LDP diets, respectively. Pigs fed the LDP diet exhibited higher gain-to-feed (G:F) ratio (P = 0.014), plasma urea nitrogen concentrations (P = 0.001), hepatic non-essential amino acids (NEAA) concentrations (P = 0.028), and carbamoyl phosphate synthetase 1 (CPS-1) activity (P = 0.018), but lower average daily feed intake (ADFI, P < 0.001) compared with those fed the LP diet. The free AA profile of the longissimus dorsi muscle (LM) in pigs fed the LDP diet showed reduced concentrations of Arg and Phe (P < 0.05), but increased the concentration of Pro compared with those fed the NP diet (P = 0.037). To trace nitrogen fate, three suckling piglets received a 15N-DP-supplemented diet. 15Nitrogen enrichment in plasma and hepatic AA at multiple time points confirmed that dietary ammonia nitrogen was absorbed and incorporated into endogenous AA. In summary, dietary supplementation with DP in the LP diet improved nitrogen metabolism and AA synthesis, thereby enhancing G:F ratios without compromising carcass traits or meat quality. However, excessive DP supplementation may suppress feed intake, underscoring the need to optimize its dietary inclusion level to ensure efficient pig production.
Feed intake-regulated nutritional compensation improves feed efficiency in sheep; however, its relevance and underlying mechanisms in high-altitude indigenous breeds such as Gangba sheep remain unclear. Ninety-six four-month-old healthy male Gangba sheep (16.20 ± 0.61 kg) were randomly assigned to four groups (six replicates per group, four sheep per replicate): ad libitum feeding (ALF) and low-, medium-, and high-restriction feeding groups (LRF, MRF, and HRF), receiving 85%, 70%, and 55% of ALF intake, respectively, for 30 d, followed by 60 d of compensatory refeeding. During the restriction period, increasing restriction intensity decreased body weight at d 30, average daily feed intake, and average daily gain (P < 0.05) and increased the feed-to-gain ratio (P < 0.001). Medium and high restriction also decreased total antioxidant capacity (P = 0.010), immunoglobulin A (P < 0.001), immunoglobulin M (P = 0.045), neutral detergent fiber digestibility (P = 0.004), ruminal papilla height (P = 0.006), and ruminal butyric acid concentration (P = 0.013). Over the whole experimental period, feed intake-regulated nutritional compensation significantly reduced average daily feed intake compared with ALF (P < 0.001). The feed-to-gain ratio was lower in the LRF group than in the ALF group (P = 0.004), indicating improved feed efficiency under low restriction feeding. Restriction feeding also induced adaptive changes in gastrointestinal development and rumen microbial diversity, with microbial α diversity recovering after refeeding while community structure remained differentiated among treatments. Overall, low feed restriction (85% of ALF) enhanced feed utilization while maintaining physiological homeostasis in Gangba sheep under forage-limited high-altitude conditions.
Reducing dietary nutrient density may lower the feed cost but compromise the growth performance in piglets. Given the ability of lysolecithin (LPI) to enhance nutrient utilization, its supplementation may help piglets adapt to a low-nutrient (LN) diet. This study aimed to investigate the effects of dietary LPI supplementation on growth performance, nutrient utilization, metabolism, and muscle development in piglets fed a LN diet. A total of 96 nursery piglets (17.0 ± 0.2 kg in initial body weight [BW] and 50 d of age) were randomly assigned to three groups in a randomized complete block design and received either the normal-nutrient diet (CON), a LN diet, or the LN diet supplemented with 400 mg/kg lysolecithin (LN-LPI) for 28 d. Each dietary treatment included 8 replicates of 4 piglets each. Results showed that the LN-LPI diet improved the average daily gain (ADG; P = 0.040) during the first two weeks, feed-to-gain ratio (F:G; P = 0.032), and BW (P = 0.065) throughout the experimental period, reaching levels comparable to those of piglets in the CON group. Compared with the LN diet, the growth-promoting effect of LPI may be attributed to its role in increasing the digestibility of ether extract (EE; P < 0.001) and gross energy (GE; P = 0.022) in diets, as well as increasing the relative weight of psoas major muscles (PMM) and the EE (P = 0.049) and crude protein (CP) content (P = 0.007) in muscle. Accordingly, compared with the LN diet, LPI supplementation decreased the blood urea nitrogen (P = 0.003) and total cholesterol (TC) concentrations (P = 0.017), and increased total superoxide dismutase (T-SOD) levels in plasma (P = 0.005) and liver (P = 0.006), along with the lower malondialdehyde (MDA) levels in blood (P < 0.001) and liver (P = 0.003). In addition, microarray analysis indicated that dietary LPI supplementation promoted expression of lipid synthesis and transport-related genes in the liver (FAS, P = 0.040; FABP5, P = 0.001; and SLC27A6, P = 0.025), and amino acid (AA) transport and synthesis-related genes (LAT, P = 0.021; LAMC3, P = 0.004), compared with the LN diet in muscle. In conclusion, this study demonstrated that the LN-LPI diet mitigated the compromised growth performance commonly observed under nutrient restriction, potentially mediated by improving nutrient utilization and redox status, and modulating lipid and protein metabolism.
This study investigated the effects of graded dietary energy and protein levels on growth, nutrient utilization, and behavior in housed young female yaks, integrating automated behavior monitoring via a YOLO-based computer vision system. Twenty-four 17-month-old Maiwa yaks (160.43 ± 14.54 kg) were randomly assigned to three dietary treatments (n = 8 per treatment): low energy and protein (LELP: net energy for gain [NEg] = 3.3 MJ/kg, crude protein [CP] = 10.50%, medium energy and protein (MEMP: NEg = 3.9 MJ/kg, CP = 12.51%), and high energy and protein (HEHP: NEg = 4.5 MJ/kg, CP = 14.50%). A 120-d feeding trial was conducted, followed by a 4-d digestion and metabolism trial. Growth performance was enhanced in the MEMP group relative to the LELP group, as indicated by significantly greater average daily gain (ADG) and a reduced feed-to-gain ratio (F/G) (P < 0.05). Nutrient metabolism was enhanced at higher dietary levels, as indicated by elevated serum urea nitrogen (BUN) and ruminal ammonia nitrogen (NH3-N) contents in the MEMP and HEHP groups (P < 0.05). Automated behavioral analysis revealed that the MEMP group spent less time standing and more time lying than the HEHP group (P < 0.05), suggesting improved welfare and rumination opportunity. Furthermore, the moderate diet (MEMP) optimized the utilization and deposition rates of both energy and nitrogen. In conclusion, a moderate energy and protein diet (NEg = 3.9 MJ/kg, CP = 12.51%) optimally supports the growth and metabolism of young female yaks under housed conditions. This study provides a scientific basis for the precise nutritional management and intelligent monitoring of yaks in intensive production systems.
The intestinal barrier serves as a critical defense system that prevents pathogen invasion and the translocation of toxins. A compromised barrier initiates a cascade of damage, including impaired mucus secretion, dysregulated inflammatory responses, reduced antioxidant capacity, and microbial dysbiosis. Emerging evidence has highlighted polyphenolic phytochemicals as promising candidates for restoring the barrier. Tannic acid (TA), a hydrolysable tannin, demonstrates multi-mechanistic potential to restore intestinal barrier integrity. This potential originates from its distinctive chemical structure, which functionally ensures the performance of these multiple biological roles. This review synthesizes current evidence on the mechanisms by which TA reinforces intestinal barrier function. Tannic acid remodels the gut microbiota to increase the production of beneficial metabolites, such as butyrate, which subsequently strengthens the physical barrier by upregulating tight junction proteins. In parallel, TA directly enhances the antioxidant defense via the Nrf2 pathway and modulates intestinal immune response by suppressing key pro-inflammatory signaling pathways, including NF-κB and NLRP3. However, the practical application of TA is limited by anti-nutritional effects, necessitating the development of mitigation strategies, such as microencapsulation or synergistic formulations. Overall, this review aims to provide insights into the potential applications of TA for the prevention and treatment of intestinal disorders in livestock and poultry.
