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ABSTRACT: The rise of operational noise as an environmental pollutant for farm animals is an emerging concern. The mechanisms through which music can alleviate oxidative stress, inflammation, and apoptosis induced by noise exposure remain underexplored. This study aims to investigate the alleviating effects and underlying mechanisms of long-term music exposure on noise-induced damage to the chicken spleen. Male Arbor Acres (AA) broilers were divided into four groups: control (C), acute noise stimulation (NS), noise stimulation with music mitigation (NSM), and music only (M). NS and NSM groups were exposed to noise (simulating sudden intensity noise, 115 to 120dB) for 10 minutes daily for a week, starting at 14-days-old. NSM and M groups then received 28 days of 6-hour daily music (Mozart K.448, 60–65 dB). The results showed that noise stimulation significantly activated the Keap-1/Nrf2 and NF-κB signaling pathways. Long-term music intervention has also been demonstrated to successfully mitigate oxidative stress and abnormal apoptosis induced by acute noise stimulation. Microscopic examination of the spleen revealed that acute noise stimulation resulted in an increase in splenic cells, a decrease in lymphocytes, and blurred boundaries between the red and white pulps in the NS group. However, these pathological changes were alleviated in the NSM group following music intervention. Compared with the control group, the NS group exhibited significantly elevated oxidative stress parameters. In contrast, music intervention in the NSM group notably improved antioxidant capacity and partially alleviated morphological abnormalities in the spleen. Additionally, noise stimulation activated the NF-κB pathway, upregulating the downstream genes of the inflammatory factors IL-1β, IL-6, and TNF-α. Noise-induced mitochondrial damage led to apoptosis, as observed by TUNEL staining, along with increased gene and protein expression of Bcl-2, Bax, Cyt-C, Casp-3, Casp-8, and Casp-9. These findings indicate that acute noise exposure can induce splenic damage via oxidative stress, inflammation, and apoptosis by modulating the Keap-1/Nrf2 and NF-κB pathways. Prolonged music stimulation effectively mitigates noise-induced damage, offering a vital experimental foundation for further research on noise pollution's impact on organisms and music's alleviating role.

ABSTRACT: To investigate the potential protective effect of prior cold stimulation on broiler intestine induced by acute cold stress (ACS). A total of 384 one-day-old broilers were divided into control (CON), ACS, cold stimulation Ⅰ (CS3+ACS), and cold stimulation Ⅱ (CS9+ACS) groups. Broilers in CON and ACS groups were reared normally, and birds in CS3+ACS and CS9+ACS groups were reared at 3℃ and 9℃ below CON group for 5 h, respectively, on alternate days from d 15 to 35. Broilers in ACS, CS3+ACS, and CS9+ACS groups were subjected to 10℃ for 24 h on d 43. Eventually, small intestine tissues were collected for histopathological observation and indexes detection. The results showed that intestinal tissues in all ACS-broilers exhibited inflammatory cell infiltrates, microvilli disruption, reduced villus length in jejunum and increased crypt depth in jejunum and ileum. Whereas these phenomena were relatively light in CS3+ACS group. Compared to CON group, mRNA expression of the TLR4/MyD88/NF-κB pathway-related genes (TLR4, MyD88, NF-κBp65, COX-2, iNOS, PTGEs, TNF-α), Th1/Th17-derived cytokines (IL-1β, IL-2, IL-8, IL-12, IFN-γ, IL-17), and HSPs (HSP40, HSP60, HSP70, HSP90) was upregulated (P < 0.05), and that of Th2-deviated cytokines (IL-4, IL-6, IL-10, IL-13) and IκBα was downregulated (P < 0.05) in small intestine in almost all ACS-broilers. Compared to ACS group, mRNA expression of most of the TLR4/MyD88/NF-κB pathway-related genes, Th1/Th17-derived cytokines, and HSPs was downregulated and that of Th2-derived cytokines was upregulated in CS3+ACS group (P < 0.05). Protein expression levels of TLR4, MyD88, p-p65/p65, p-IκBα/IκBα, IKK, TNF-α, IL-1β, IL-10, and HSPs were similar to their mRNA expression. The concentration of sIgA and activities of CAT, SOD, and GSH-px were decreased and MDA and H2O2 were increased in ACS and CS9+ACS groups compared to CON group (P < 0.05). Therefore, cold stress caused oxidative stress and inflammation, leading to gut immune dysfunction; while mild cold stimulation at 3℃ below normal rearing temperature alleviated cold stress-induced intestinal injure and dysfunction by modulating the TLR4/MyD88/NF-κB pathway in broilers.

As an environmental enrichment, music can positively influence the immune function, while noise has an adverse effect on the physical and mental health of humans and animals. However, whether music-enriched environments mitigate noise-induced acute stress remains unclear. To investigate the anti-inflammatory effects of music on the immune organs of broiler chickens under conditions of early-life acute noise stress, 140 one-day-old white feather broilers (AA) were randomly divided into four groups: control (C), the music stimulation (M) group, the acute noise stimulation (N) group, the acute noise stimulation followed by music (NM) group. At 14 days of age, the N and NM groups received 120 dB noise stimulation for 10 min for one week. After acute noise stimulation, the NM group and M group were subjected to continuous music stimulation for 14 days (6 h per day, 60 dB). At 28 days of age, the body temperature of the chicks, the histopathological changes, quantification of ROS-positive density and apoptosis positivity in tissues of spleen, thymus, and bursa of Fabricius (BF) were measured. The results showed that acute noise stimulation led to an increase in the number and area of splenic microsomes and the cortex/medulla ratio of the detected immune organs. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) of immune tissues of broilers in N group were decreased compared to the broilers in C group, while the mRNA levels of malondialdehyde (MDA), TNF-α, IL-1, and IL-1β increased. In addition, the gene and protein expression levels of IKK, NF-κB, and IFN-γ of three immune organs from broilers in the N group were increased. Compared to the C and N group, chickens from the NM group showed a decrease in the number and area of splenic follicles, an increase in the activities of SOD and GSH-Px, and a decrease in the expression levels of MDA, TNF-α, IL-1, and IL-1β. Therefore, a music-enriched environment can attenuate oxidative stress induced by acute noise stimulation, inhibiting the activation of the NF-κB signaling pathway and consequently alleviating the inflammatory response in immune organs.

ABSTRACT: Intermittent cold stimulation (ICS) enhances broilers’ resistance to cold stress. Nonetheless, further research is needed to investigate the underlying mechanisms that enhance cold stress resistance. A total of 160 one-day-old male Ross 308 broilers were randomly divided into 2 groups (CC and CS5), with the CC group managing temperature according to the standard for broiler growth stages, while the CS5 group were subjected to cold stimulation at a temperature 3℃ lower than the CC group for 5 h, every 2 d from 15 to 35 d. Sampling was conducted at 36 d (36D), 50 d (50D) and after acute cold stress for 24 h (Y24). First, we examined the effects of ICS on broiler growth performance, meat quality, antioxidant capacity, and lipid metabolism. The results demonstrated that ICS enhanced the performance of broilers to a certain degree. Specifically, the average weight gain in the CS5 group was significantly higher than that of the CC group, and the feed conversion ratio significantly decreased compared to CC at 4 W and 6 W (P ≤ 0.05). Compared with the CC group, cold stimulation significantly reduced drip loss, shearing force, and yellowness (a* value) of chicken meat, while significantly increased redness (b* value) (P ≤ 0.05). At Y24, the levels of T-AOC and GSH-PX in the serum of the CS5 group were significantly higher than those of the CC group, while the level of MDA was significantly lower (P ≤ 0.05). The content of TG, FFA, and VLDL in the serum of the CS5 group was significantly elevated, whereas the level of TC and HDL was significantly lower (P ≤ 0.05). In addition, we further explored whether AMPK-mTOR pathway is involved in the regulation of changes in lipid metabolism and the possible regulatory mechanisms downstream of the signaling pathway. The results showed that ICS significantly upregulated the expression levels of AMPK mRNA and protein in the liver of the CS5 group at 36D and Y24, while significantly down-regulating mTOR (P ≤ 0.05). Compared with the CC group, ICS significantly down-regulated the mRNA expression levels of lipid synthesis and endoplasmic reticulum stress-related genes (SREBP1c, FAS, SCD, ACC, GRP78 and PERK) at 36D and Y24, while significantly up-regulating the mRNA expression levels of lipid decomposition and autophagy-related genes (PPAR and LC3) (P ≤ 0.05). In addition, at Y24, the protein expression levels of endoplasmic reticulum stress-related genes (GRP78) in the CS5 group were significantly lower, while autophagy-related genes (LC3 and ATG7) were significantly higher (P ≤ 0.05). ICS can affect meat quality and lipid metabolism in broilers, and when broilers are subjected to acute cold stress, broilers trained with cold stimulation have stronger lipid metabolism capacity.