Effects of ß-carotene supplementation in the diet of laying breeder hens on the growth performance and liver development of offspring chicks.

This experiment was conducted to evaluate the growth performance, growth regulating factors, and liver morphology of chicks hatched from egg-laying breeding hens dietary supplemented with additives (ß-carotene). Hy-line breeding hens were allocated into three groups with three replicates/group. The dietary treatments were as follows: basal diet as a control (Con), basal diet supplemented with 120 (ßc-L) or 240 (ßc-H) mg/kg of ß-carotene diet. After 6 weeks, the eggs were collected and incubated. The hatched chicks were fed the same diet. The results showed that chicks in the ßc-L group increased in body weight at 21 days (p < 0.01). At 42 days, chicks in the ßc-H group showed a significant increase in tibia length (p < 0.05). The liver index increased in the ßc-L and ßc-H groups at 7 days (p < 0.05). Serum HGF (7, 14, 21, and 42 days) and leptin (14 days) were significantly increased in the group supplemented with ßc. Hepatic GHR (14 days), IGF-1R (14 days), and LEPR (21 days) mRNA expression were significantly increased. In addition, there was an increase in PCNA-positive cells in the liver of chicks in the ßc group. In conclusion, the addition of ß-carotene to the diet of laying breeder hens was more advantageous in terms of growth performance and liver development of the offspring.

Glycine regulates lipid peroxidation promoting porcine oocyte maturation and early embryonic development.

In vitro-cultured oocytes are separated from the follicular micro-environment in vivo and are more vulnerable than in vivo oocytes to changes in the external environment. This vulnerability disrupts the homeostasis of the intracellular environment, affecting oocyte meiotic completion, and subsequent embryonic developmental competence in vitro. Glycine, one of the main components of glutathione (GSH), plays an important role in the protection of porcine oocytes in vitro. However, the protective mechanism of glycine needs to be further clarified. Our results showed that glycine supplementation promoted cumulus cell expansion and oocyte maturation. Detection of oocyte development ability showed that glycine significantly increased the cleavage rate and blastocyst rate during in vitro fertilization (IVF). SMART-seq revealed that this effect was related to glycine-mediated regulation of cell membrane structure and function. Exogenous addition of glycine significantly increased the levels of the anti-oxidant GSH and the expression of anti-oxidant-related genes (glutathione peroxidase 4 [GPX4], catalase [CAT], superoxide dismutase 1 [SOD1], superoxide dismutase 2 [SOD2], and mitochondrial solute carrier family 25, member 39 [SLC25A39]), decreased the lipid peroxidation caused by reactive oxygen species (ROS) and reduced the level of malondialdehyde (MDA) by enhancing the functions of mitochondria, peroxisomes and lipid droplets (LDs) and the levels of lipid metabolism-related factors (peroxisome proliferator activated receptor coactivator 1 alpha [PGC-1α], peroxisome proliferator-activated receptor γ [PPARγ], sterol regulatory element binding factor 1 [SREBF1], autocrine motility factor receptor [AMFR], and ATP). These effects further reduced ferroptosis and maintained the normal structure and function of the cell membrane. Our results suggest that glycine plays an important role in oocyte maturation and later development by regulating ROS-induced lipid metabolism, thereby protecting against biomembrane damage.

Production of high-quality gametes is the premise of livestock reproduction and conservation of germplasm resources, especially high-quality oocytes, as oocyte quality determines the quality of offspring. Due to the limitations in approaches and the number of mature oocytes in vivo, in vitro maturation (IVM) culture has become an important way to obtain mature oocytes. However, IVM-cultured oocytes are separated from the follicular microenvironment in vivo and are, thus, more vulnerable than in vivo oocytes to changes in the external environment. Our study was conducted to determine if exogenous supplementation of glycine, the highest content of amino acids in oviduct fluid and follicular fluid, can improve oocyte maturation efficiency in vitro, and analyze the mechanism of glycine. This study demonstrated that glycine can maintain redox balance and block reactive oxygen species-induced lipid peroxidation, thereby protecting against biomembrane damage and reducing the occurrence of ferroptosis to maintain normal oocyte development function. This study will provide a theoretical basis for preventing and improving oxidative damage during oocyte culture in vitro.

Glycine Ameliorates Endoplasmic Reticulum Stress Induced by Thapsigargin in Porcine Oocytes.

The endoplasmic reticulum (ER) is a multifunctional organelle in the cytoplasm that plays important roles in female mammalian reproduction. The endoplasmic reticulum and mitochondria interact to maintain the normal function of cells by maintaining intracellular calcium homeostasis. As proven by previous research, glycine (Gly) can regulate the intracellular free calcium concentration ([Ca2+]i) and enhance mitochondrial function to improve oocyte maturation in vitro. The effect of Gly on ER function during oocyte in vitro maturation (IVM) is not clear. In this study, we induced an ER stress model with thapsigargin (TG) to explore whether Gly can reverse the ER stress induced by TG treatment and whether it is associated with calcium regulation. The results showed that the addition of Gly could improve the decrease in the average cumulus diameter, the first polar body excretion rate caused by TG-induced ER stress, the cleavage rate and the blastocyst rate. Gly supplementation could reduce the ER stress induced by TG by significantly improving the ER levels and significantly downregulating the expression of genes related to ER stress (Xbp1, ATF4, and ATF6). Moreover, Gly also significantly alleviated the increase in reactive oxygen species (ROS) levels and the decrease in mitochondrial membrane potential (ΔΨ m) to improve mitochondrial function in porcine oocytes exposed to TG. Furthermore, Gly reduced the [Ca2+]i and mitochondrial Ca2+ ([Ca2+]m) levels and restored the ER Ca2+ ([Ca2+]ER) levels in TG-exposed porcine oocytes. Moreover, we found that the increase in [Ca2+]i may be caused by changes in the distribution and expression of inositol 1,4,5-triphosphate receptor (IP3R1) and voltage-dependent anion channel 1 (VDAC1), while Gly can restore the distribution and expression of IP3R1 and VDAC1 to normal levels. Apoptosis-related indexes (Caspase 3 activity and Annexin-V) and gene expression Bax, Cyto C, and Caspase 3) were significantly increased in the TG group, but they could be restored by adding Gly. Our results suggest that Gly can ameliorate ER stress and apoptosis in TG-exposed porcine oocytes and can further enhance the developmental potential of porcine oocytes in vitro.

Gut microbiota regulation and anti-inflammatory effect of ß-carotene in dextran sulfate sodium-stimulated ulcerative colitis in rats.

ß-Carotene displays antioxidant and anti-inflammatory activities and prevents the development of cancer. Ulcerative colitis (UC) is a kind of inflammatory bowel disease that is accompanied by a certain risk of colon cancer. However, the role of ß-carotene in the modulation of gut microbiota and UC improvement is unclear. In this research, the properties of ß-carotene on anti-inflammatory and the composition of gut microbiota were evaluated in a rat model of UC induced by dextran sulfate sodium (DSS). The results revealed that ß-carotene significantly (p < 0.05) decreased the severity of colitis in rats, as assessed using body weight (6.00 ± 1.73%), colon length (22.23 ± 0.53%), and disease activity index, and improved the structure of the colon damaged. Moreover, colonic levels of proinflammatory cytokines were significantly lower following ß-carotene supplementation. ß-Carotene intervention also lowered the expression levels of phosphorylated p65 (0.60 ± 0.02), p38 (0.57 ± 0.00), Erk (0.63 ± 0.04), and JNK (0.70 ± 0.00). The result of the relative abundance of gut microbiota showed that DSS administration significantly changed the microbial structure at the phylum and genus levels of rats. Furthermore, ß-carotene treatment significantly increased the abundance of Faecalibacterium, the levels of which negatively correlated with the levels of inflammatory cytokines. Faecalibacterium may be a potential target in the alleviation of DSS-induced UC. ß-Carotene can alleviate DSS-induced UC through the regulation of gut microbiota. This study provides a reference for the rational use of ß-carotene in the treatment of UC. PRACTICAL APPLICATION: ß-Carotene can relieve ulcerative colitis and regulate the gut microbiota; the nutritional intervention of ß-carotene enhancing animal health.