This study was conducted to evaluate the effect of curcumin on laying performance, egg quality, biochemical indicators, hormone levels, and immune activity in hens under heat stress. Hy-Line brown hens (280-day-old) were fed with 0, 100, 150, and 200 mg/kg of curcumin during a 42-D experiment. Compared with the control treatment, supplementation with 150 mg/kg of curcumin improved laying performance and egg quality by significantly increasing egg production, eggshell thickness, eggshell strength (P < 0.01), and albumen height (P < 0.05) while decreasing the feed-to-egg ratio. Antioxidant activity was improved by significantly increasing the activity of superoxide dismutase and glutathione peroxidase but decreasing malondialdehyde levels in serum (P < 0.05) and significantly increasing the levels of follicle-stimulating hormone, luteinizing hormone, estradiol, IgG, IgA, and complement C3 activity in serum (P < 0.05). These results indicated that supplemental 150 mg/kg curcumin can improve productive performance, antioxidant enzyme activity, and immune function in laying hens under the heat stress conditions applied in the present study.

To investigate the effect of genetic selection on meat quality in ducks, twenty of each fast growth ducks (LCA) and slow growth ducks (LCC) selected from F6 generation of Cherry Valley ducks (♂) x Liancheng white ducks (♀) were analyzed for carcass characteristics, meat quality (physicochemical and textural characteristics), amino acid and fatty acid profiles at 7 wk. Results showed that live body weight, slaughter weight, eviscerated yield and abdominal fat percentage of LCA were significantly higher than those in LCC ducks (P < 0.01). Moreover, the average area and diameter of myofiber were larger in LCA than LCC ducks (P < 0.01). The breast and thigh muscles of LCA exhibited significantly lower water holding capacity and thermal loss compared with LCC ducks (P < 0.01). In addition, the content of nonessential amino acids (Glu, Asp, and Arg) in breast muscles and Asp, Ser, Thr, and Met in thigh muscles was higher in LCC than LCA ducks (P < 0.05). The proportion of polyunsaturated fatty acids (PUFA) in breast muscles of LCC was higher than LCA ducks (P < 0.05). However, the content of saturated fatty acids (SFA) in breast and thigh muscles of LCA was higher compared with LCC ducks (P < 0.05). The proportion of monounsaturated fatty acids (MUFA) in thigh muscles was significantly higher in LCC compared with LCA ducks (P < 0.01). Finally, multiple traits were evaluated by applying principal component analysis (PCA) and the results indicated that PUFA and SFA in breast muscles of LCA played important roles in meat quality, followed by Warner-Bratzler shear force (WBSF) and MUFA. However, water holding capacity (WHC) had a dominant effect in meat quality of thigh muscles in both LCA and LCC ducks.

Introduction: Heat stress is harmful to the health of humans and animals, more and more common, as a consequence of global warming, while the mechanism that heat stress modulates skeletal development remains unknown. Hence, we conducted a model of heat stress in vitro.Methods: We used Hu sheep myoblasts as the research object, real-time quantitative PCR (RT-qPCR) and western blot (WB) were conducted to detect the expression of mRNA and protein in heat-stressed myoblasts. The would-healing assay was used to detect the migration of myoblasts. The mitochondria were observed by a transmission electron microscope.Results: mRNA and protein expression of HSP60 was significantly enriched in the heat-stressed myoblasts during proliferation and differentiation (p < 0.05). In our study, we indicated that heat stress enriched the intracellular ROS of the myoblasts (p < 0.001), leading to an increase in autophagy in the myoblasts to induce apoptosis. The results demonstrated that the protein expression of LC3B-1 and BCL-2 was significantly increased in myoblasts under heat stress during proliferation and differentiation (p < 0.05). Additionally, heat stress inhibited mitochondrial biogenesis and function and reduced the mitochondrial membrane potential and downregulated the expression of mtCo2, mtNd1 and DNM1L (p < 0.05) in myoblasts during proliferation and differentiation. Consequently, heat stress inhibited the proliferation and differentiation of the myoblasts, in accordance with the downregulation of the expression of PAX7, MYOD, MYF5, MYOG and MYHC (p < 0.05). Moreover, heat stress also inhibited the cell migration of the myoblasts.Discussion: This work demonstrates that heat stress inhibits proliferation and differentiation, and accelerates apoptosis by impairing mitochondrial function and promoting autophagy, which provides a mechanism to understand heat stress affects the development of the skeletal muscle.

Genistein is abundant in the corn-soybean meal feed. Little information is available about the effect of dietary genistein on the intestinal transcriptome of chicks, especially when suffering from intestinal injury. In this study, 180 one-day-old male ROSS 308 broiler chickens were randomly allocated to 3 groups, with 4 replicates (cages) of 15 birds each. The treatments were as follows: chicks received a basal diet (CON), a basal diet and underwent lipopolysaccharide-challenge (LPS), or a basal diet supplemented with 40 mg/kg genistein and underwent LPS-challenge (GEN). LPS injection induced intestinal injury and inflammatory reactions in the chicks. Transcriptomic analysis identified 7,131 differently expressed genes (3,281 upregulated and 3,851 downregulated) in the GEN group compared with the LPS group (P adjusted value < 0.05, |fold change| > 1.5), which revealed that dietary genistein exposure altered the gene expression profile and signaling pathways in the ileum of LPS-treated chicks. Furthermore, dietary genistein improved intestinal morphology, mucosal immune function, tight junction, antioxidant activity, apoptotic process, and growth performance, which were adversely damaged by LPS injection. Therefore, adding genistein into the diet of chicks can alter RNA expression profile and ameliorate intestinal injury in LPS-challenged chicks, thereby improving the growth performance of chicks with intestinal injury.

Testosterone (T) is essential for muscle fiber formation and growth. However, the specific mechanism by which T regulates skeletal muscle development in chicken embryos remains unclear. In this study, the role of T in myoblast proliferation both in vivo and in vitro was investigated. Results showed that the T administration significantly increased the ratio of breast muscle and leg muscle. T induced a significant increase in the cross-sectional area (CSA) and density of myofiber and the ratio of PAX7-positive cells in the skeletal muscle. Exogenous T also induced the upregulation of myogenic regulatory factors (MRFs) and cyclin-dependent kinases (CDK2)/Cyclin D1 (CCND1) and protein levels of androgen receptor (AR), p-Akt and PAX7. Furthermore, T treatment significantly promoted myoblasts cultured in vitro entering a new cell cycle and increased PAX7-positive cells. The mRNA and protein expression of AR and PAX7 were upregulated when treated with T compared to that of the control. The addition of T induced proliferation accompanied by increasing AR level as well as PI3K (Phosphoinositide 3-kinase)/Akt activation. However, T-induced proliferation was attenuated by AR, PI3K, and Akt-specific inhibitors. These data indicated that the pro-proliferative effect of T was regulated though AR in response to the activation of PI3K/Akt signalling pathway.

The aim of this study was to investigate the effects of puerarin (Pue), a phytoestrogen, on the production performance, egg quality, endocrine hormones, antioxidant capacity, and intestinal morphology in aged laying hens. A total of 180 Hy-Line Brown hens aged 480 d were randomly divided into 4 groups (n = 45 per group) and fed 0, 200, 400, and 800 mg/kg of Pue (Con, L-Pue, M-Pue, and H-Pue, respectively) during a 42-d experiment. Compared with the Con treatment, supplementation with H-Pue improved laying performance and egg quality by significantly increasing egg production, average egg weight, albumen height, yolk weight, and Haugh unit (P < 0.05) while decreasing the feed conversion ratio (P < 0.05). A diet supplemented with H-Pue significantly decreasing serum total triglycerides, total cholesterol, and low-density lipoprotein cholesterol, alanine aminotransferase (P < 0.05), and significantly increasing serum levels of follicle-stimulating hormone, luteinizing hormone and progesterone (P < 0.05). Antioxidant activity was improved by significantly increasing the activity of total antioxidant capacity, glutathione peroxidase and catalase but decreasing malondialdehyde levels in serum, jejunum, and ileum (P < 0.05), and superoxide dismutase activity exhibited a significantly increase in the jejunum and ileum (P < 0.05). Villus height and the ratio of villus height to crypt depth (P < 0.05) were significantly increased in the jejunum and ileum. In the jejunal and ileal mucosa, the three treatment groups increased the mRNA expression levels of Claudin-1 and Claudin-2 compared with Con (P < 0.05), and no significant effect was observed on the expression of Occludin and ZO-1. The results showed that dietary supplementation with Pue could improve the laying performance, egg quality, antioxidant capacity, hormonal profile, and intestinal morphology of aged laying hens.