Productive performance, egg quality, hematological parameters and serum chemistry of laying hens fed diets supplemented with certain fat-soluble vitamins, individually or combined, during summer season.

This present study aimed to determine the efficacy of supplementing layer diets with vitamin A (0, 8,000 and 16,000 IU/kg diet) and vitamin E (0, 250 and 500 mg/kg diet) either individually or in combination on egg production and quality, and blood hematology and chemistry of birds reared under summer conditions. A total of 135 Bovans Brown laying hens were distributed to 9 treatment groups with 5 replicates of 3 hens/pen in a 3 × 3 factorial design. A significant improvement in feed conversion ratio (FCR) was observed as supplementary vitamin A or E increased (P ≤ 0.01). Hens fed diets supplemented with 16,000 IU vitamin A plus 500 mg vitamin E/kg diet had the best FCR among all groups. Egg quality traits were not significantly affected by the interaction of vitamin A and vitamin E levels. There was a significant increase in monocytes (P ≤ 0.01) and a decrease in basophils counts (P ≤ 0.05) in response to vitamin E. Significant decreases were observed in packed cell volume (PCV), thyroxine (T4), alanine transferase (ALT), albumin, total cholesterol and total lipids ( (P ≤ 0.05 or P ≤ 0.01) P ≤ 0.01) , and increases were observed in serum concentrations of globulin (P ≤ 0.05) and calcium (P ≤ 0.01) due to vitamin A. The combination of 0 IU vitamin A and 500 mg vitamin E/kg diet had the highest values of PCV (40.09%) and hemoglobin (Hb) (10.33 mg/100 mL) among all groups. Vitamin E raised serum values of total protein, total cholesterol and total lipids (P ≤ 0.05 or P ≤ 0.01). Feed intake, FCR, PCV, Hb, lymphocytes, monocytes, eosinophils, T4, ALT and total protein were significantly affected by the interaction of vitamins A and E (P ≤ 0.05 or P ≤ 0.01). The interaction of vitamins A and E was only significant with respect to serum total protein (P ≤ 0.05). It can be concluded that layer diets supplemented with vitamins A and E had good results in alleviating the harmful impacts of high ambient temperature. The combination of 16,000 IU vitamin A and 500 mg vitamin E per kilogram diet is preferable for obtaining better production of laying hens reared under hot summer conditions.

Impacts of selenium and vitamin E supplementation on mRNA of heat shock proteins, selenoproteins and antioxidants in broilers exposed to high temperature.

The study was carried out to investigate the effect of dietary selenium (Se) and vitamin E (VE) supplementation on mRNA level of heat shock proteins, selenoproteins, and antioxidant enzyme activities in the breast meat of broilers under summer heat stress conditions. A total of 200 male broilers (Ross 308) of 1 day age were randomly separated into 4 groups in a complete randomized design and were given a basal diet (Control, 0.08 mg Se/kg diet) or basal diet supplemented with VE (250 mg/kg VE), sodium selenite (0.2 mg/kg Se), or Se + VE (0.2 mg/kg Se + 250 mg/kg VE) to investigate the expression of key antioxidant and heat shock protein (HSP) genes under high temperature stress. Dietary Se, VE and Se + VE significantly enhanced the activities and mRNA levels of catalase as well as superoxide dismutase (SOD) but decreased the mRNA levels of HSP70 and HSP90. Se alone or combined with VE increased the concentration of selenoprotein P and selenoproteins mRNA level and decreased the expression of HSP60. In addition, Se and Se + VE significantly enhanced the glutathione peroxidase (GPx) activity and the expression of GPx1 and GPx4 in breast muscle tissues. It is noteworthy that all the treatments significantly decreased malondialdehyde (MDA) level in the breast meat. Overall results showed that Se in combination with VE has maximal effects to mitigate heat stress. Based on given results it can be recommended that Se + VE are a suitable dietary supplement for broilers to ameliorate the negative effects of summer heat stress conditions.

Intrauterine growth retardation promotes fetal intestinal autophagy in rats via the mechanistic target of rapamycin pathway.

Intrauterine growth retardation (IUGR) impairs fetal intestinal development, and is associated with high perinatal morbidity and mortality. However, the mechanism underlying this intestinal injury is largely unknown. We aimed to investigate this mechanism through analysis of intestinal autophagy and related signaling pathways in a rat model of IUGR. Normal weight (NW) and IUGR fetuses were obtained from primiparous rats via ad libitum food intake and 50% food restriction, respectively. Maternal serum parameters, fetal body weight, organ weights, and fetal blood glucose were determined. Intestinal apoptosis, autophagy, and the mechanistic target of rapamycin (mTOR) signaling pathway were analyzed. The results indicated that maternal 50% food restriction reduced maternal serum glucose, bilirubin, and total cholesterol and produced IUGR fetuses, which had decreased body weight; blood glucose; and weights of the small intestine, stomach, spleen, pancreas, and kidney. Decreased Bcl-2 and increased Casp9 mRNA expression was observed in IUGR fetal intestines. Analysis of intestinal autophagy showed that the mRNA expression of WIPI1, MAP1LC3B, Atg5, and Atg14 was also increased, while the protein levels of p62 were decreased in IUGR fetuses. Compared to NW fetuses, IUGR fetuses showed decreased mTOR protein levels and enhanced mRNA expression of ULK1 and Beclin1 in the small intestine. In summary, the results indicated that maternal 50% food restriction on gestational days 10-21 reduced maternal serum glucose, bilirubin, and total cholesterol contents, and produced IUGR fetuses that had low blood glucose and reduced small intestine weight. Intestinal injury of IUGR fetuses caused by maternal food restriction might be due to enhanced apoptosis and autophagy via the mTOR signaling pathway.