Studies on trimethylamine (TMA) in egg yolk have focused on how it impacts the flavor of eggs, but there has been little focus on its other functions. We designed an in vitro antibacterial test of TMA according to TMA concentrations that covered the TMA contents typically found in egg yolk. The change in TMA content in yolk was analyzed at different storage temperatures and for different storage durations. The known antibacterial components of eggs, including the cuticle quality of the eggshell and the lysozyme activity and content in egg white, were also assessed. The total bacterial count (TBC) of different parts of eggs were detected. The results showed that the inhibitory effect of TMA on Escherichia coli (E. coli) growth increased with increasing TMA concentration, and the yolk TMA content significantly increased with storage duration (p < 0.05). The cuticle quality and lysozyme content and activity significantly decreased with storage time and increasing temperature, accompanied by a significant increase in the TBC on the eggshell surface and in the egg white (p < 0.05). This work reveals a new role for trace TMA in yolks because it reduces the risk of bacterial colonization, especially when the antibacterial function of eggs is gradually weakened during storage.

The T329S mutation in flavin-containing monooxygenase 3 (FMO3) impairs the trimethylamine (TMA) metabolism in laying hens. The TMA metabolic pathway is closely linked to lipid metabolic diseases, such as atherosclerosis and fatty liver disease. We aimed to evaluate the effects of the T329S mutation in FMO3 on lipid metabolism in chickens during the late laying period. We selected 18 FMO3 genotyped individuals (consisting of six AA, six AT, and six TT hens) with similar body weight and production performance. The lipid metabolism and deposition characteristics of the laying hens with different genotypes were compared. The T329S mutation moderated the serum-lipid parameters in TT hens compared to those in AA and AT hens from 49 to 62 weeks. Furthermore, it reduced the serum trimethylamine N-oxide concentrations and increased the serum total bile acid (p < 0.05) and related lipid transporter levels in TT hens. Moreover, it significantly (p < 0.01) decreased atherosclerotic lesions and hepatic steatosis in TT hens compared to those in the AA and AT hens. Our findings may help improve the health status in laying hens during the late laying period.

Background: Most duck eggs possess a fishy odor, indicating that ducks generally exhibit impaired trimethylamine (TMA) metabolism. TMA accumulation is responsible for this unpleasant odor, and TMA metabolism plays an essential role in trimethylaminuria (TMAU), also known as fish odor syndrome. In this study, we focused on the unusual TMA metabolism mechanism in ducks, and further explored the unclear reasons leading to the debilitating TMA metabolism. Methods: To achieve this, transcriptome, proteome, and metagenome analyses were first integrated based on the constructed duck populations with high and low TMA metabolism abilities. Additionally, further experiments were conducted to validate the hypothesis regarding the limited flavin-containing monooxygenase 3 (FMO3) metabolism ability of ducks. Results: The study demonstrated that liver FMO3 and cecal microbes, including Akkermansia and Mucispirillum, participated in TMA metabolism in ducks. The limited oxidation ability of FMO3 explains the weakening of TMA metabolism in ducks. Nevertheless, it decreases lipid deposition and increases antibacterial activity, contributing to its survival and reproduction during the evolutionary adaptation process. Conclusions: This study demonstrated the function of FMO3 and intestinal microbes in regulating TMA metabolism and illustrated the biological significance of FMO3 impairment in ducks.

Background: Choline is an important nutrient, playing key roles in numerous metabolic pathways relevant to animal health.Objectives: The objective of this study was to evaluate the effect of dietary choline on the lipid parameters, cardiovascular health (CVH), and levels of egg trimethylamine (TMA) and cholesterol in breeder ducks during the late laying period.Methods: A total of 60 Jingjiang ducks were randomly separated into six replicates of 10 ducks each. After peak production until 65 weeks of age, the birds were fed a control basal diet. The same ducks served as the control group until 65 weeks of age, when the same ducks served as the choline‐supplemented group, after 15 days of dietary choline supplementation at 2955 mg/kg choline above and over the basal diet initially provided. The 15 days of choline supplementation included an initial 5‐day acclimatisation period.Results: Dietary choline supplementation increased serum TMA (p < 0.01), high‐density lipoprotein cholesterol, very low‐density lipoprotein, and triglyceride levels in older breeder ducks. However, it did not change the levels of trimethylamine N‐oxide but decreased the atherosclerosis index compared with those of the control group (p < 0.01). Moreover, it increased (p < 0.01) the egg yolk TMA levels but did not change the concentrations of cholesterol in egg yolk.Conclusions: Dietary choline supplementation had a beneficial effect on lipid parameters and CVH in older breeder ducks, although it increased the serum and egg yolk TMA levels.

The reproductive efficiency of modern breeding sows is commonly restricted by a mismatch between high genetic reproductive potential and insufficient voluntary feed intake during critical physiological periods. This review comprehensively examines the physiological, nutritional, and management mechanisms regulating feed intake in sows and their implications for reproductive performance, synthesizing recent advances across neuroendocrine regulation, metabolic signaling, immune-related pathways, and precision feeding strategies. We construct an integrated framework involving three core dimensions: (1) Physiological regulation: the hypothalamic–pituitary–adrenal, hypothalamic–pituitary–gonadal, and hypothalamic–pituitary–spleen axes functionally interact via shared neuroimmune pathways within the hypothalamic–pituitary–immune axis, coordinately regulating feeding patterns and reproductive cyclicity through core hormonal and inflammatory signaling molecules. Perinatal stress induces pro-inflammatory cytokine secretion, activates the intestinal JAK-STAT3 pathway, and upregulates intestinal hepcidin expression, impairing intestinal barrier integrity and triggering persistent inflammation. These peripheral inflammatory signals modulate hypothalamic neuropeptide Y and Proopiomelanocortin expression, forming a negative feedback loop that suppresses feeding behavior. (2) Nutritional regulation: dietary nutrients and specific flavor compounds reshape intestinal satiety signaling, improving piglet growth performance and survival rates, while optimized dietary composition and functional additive supplementation enhance sow feed intake capacity. (3) Management strategies: standardized feeding regimes and optimal rearing environments regulate nutrient digestion and gut hormone secretion. Major knowledge gaps include the translational potential of precision nutrition approaches, biomarker validation for feed intake monitoring, and the scalability of integrated interventions under commercial production conditions. This review provides a multidimensional framework integrating physiological, nutritional, and management strategies to enhance sow feed intake, offering theoretical insights and practical guidance for sustainable pig production.

This study investigated the effects of dietary N-acetylcysteine (NAC) supplementation on the antioxidant capacity and production performance of broiler breeder hens and their offspring. The breeder hens were randomly assigned to two groups: one received a corn-soybean meal-based control diet, while the other was supplemented with 1 g/kg NAC. Eggs from each group were randomly selected for incubation, and the offspring broilers were fed a basal diet. Dietary NAC treatment not only increased the albumen height and Haugh unit values of eggs but also improved fertilization rates (P < 0.05). Additionally, broiler chicks from the NAC-treated hens demonstrated higher eviscerated weight, full evisceration rate, and semi-eviscerated weight (P < 0.05). Dietary supplementation with NAC in breeder hens enhanced antioxidant capacity, as evidenced by increased total antioxidant capacity and catalase (CAT) activity in egg yolk, elevated CAT and glutathione peroxidase activities in breeder hen serum, and higher superoxide dismutase activity in chick serum. In particular, the NAC-treated group showed significantly higher glutathione levels and lower malondialdehyde levels throughout the transition from breeder hens to offspring (P < 0.05). Furthermore, maternal NAC treatment decreased the relative mRNA expression levels of pro-inflammatory cytokines interferon-γ, interleukin 18, and interleukin 6 in the ileum of the offspring broilers (P < 0.05). In conclusion, maternal dietary supplementation with NAC can continuously enhance the antioxidant capability and intestinal barrier function of chicken offspring, while also improving egg quality, growth performance and slaughter performance.