Effects of a yeast-derived product on growth performance, antioxidant capacity, and immune function of broilers.

Yeast culture plus enzymatically hydrolyzed yeast cell wall (YC-EHY) contains crude protein, mannan-oligosaccharide, ß-glucan and yeast culture. This study was carried out to explore the effects of dietary YC-EHY at different levels on growth performance, antioxidant capacity, and immune function of broiler chickens. A total of 320 one-day-age male broiler chicks were allocated into 4 groups and were fed with a basal diet supplemented with 0 mg/kg (the control group), 50 mg/kg, 100 mg/kg, 150 mg/kg YC-EHY for 42 d. Dietary YC-EHY improved average daily gain and feed efficiency during the starter, grower, and overall periods as well as average body weight of broiler chickens on 42 d (linear and quadratic, P < 0.05). Broiler chickens fed with YC-EHY quadratically increased jejunal sucrase activity on 21 d (quadratic, P < 0.05), and linearly and quadratically enhanced maltase activity on 21 and 42 d (linear and quadratic, P < 0.05). Supplementing YC-EHY linearly and quadratically enhanced jejunal superoxide dismutase (SOD) activity on 21 and 42 d and glutathione peroxidase (GPX) activity on 42 d whereas decreased malonaldehyde (MDA) concentration on 42 d (linear and quadratic, P < 0.05). Consistently, the jejunal genes expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and SOD1 on 21 and 42 d, heme oxygenase-1 (HO-1) and GPX1 on 42 d were enhanced by YC-EHY supplementation (linear and quadratic, P < 0.05). The concentrations of jejunal immunoglobulin G (IgG) on 21 and 42 d and secreted immunoglobulin A (SIgA) on 42 d were linearly and quadratically elevated by supplementing YC-EHY (linear and quadratic, P < 0.05). Dietary YC-EHY quadratically increased jejunal IgG and IgM genes expression on 21 d (quadratic, P < 0.05), and linearly and quadratically enhanced the genes expression of IgG and IgM on 42 d (linear and quadratic, P < 0.05). Overall, this study indicated that supplementing YC-EHY could exert beneficial effects on growth performance, intestinal antioxidant capacity and immune function in broiler chickens.

Zearalenone regulates key factors of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1-nuclear factor erythroid 2-related factor 2 signaling pathway in duodenum of post-weaning gilts.

OBJECTIVE: This study explored the mechanism of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway under conditions of zearalenone (ZEA)-induced oxidative stress in the duodenum of post-weaning gilts. METHODS: Forty post-weaning gilts were randomly allocated to four groups and fed diets supplemented with 0, 0.5, 1.0, or 1.5 mg/kg ZEA. RESULTS: The results showed significant reductions in the activity of the antioxidant enzymes total superoxide dismutase and glutathione peroxidase and increases the malondialdehyde content with increasing concentrations of dietary ZEA. Immunohistochemical analysis supported these findings by showing a significantly increased expression of Nrf2 and glutathione peroxidase 1 (GPX1) with increasing concentrations of ZEA. The relative mRNA and protein expression of Nrf2, GPX1 increased linearly (p<0.05) and quadratically (p<0.05), which was consistent with the immunohistochemical results. The relative mRNA expression of Keap1 decreased linearly (p<0.05) and quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet. The relative mRNA expression of modifier subunit of glutamate-cysteine ligase (GCLM) increased quadratically (p<0.05) in all ZEA treatment groups and the relative mRNA expression of quinone oxidoreductase 1 (NQO1) catalytic subunit of glutamate-cysteine ligase decreased linearly (p<0.05) and quadratically (p<0.05) in the ZEA1.0 group and ZEA1.5 group. The relative protein expression of Keap1 and GCLM decreased quadratically (p<0.05) in the duodenum as the ZEA concentration increased in the diet, respectively. The relative protein expression of NQO1 increased linearly (p<0.05) and quadratically (p<0.05) in all ZEA treatment groups in the duodenum. CONCLUSION: These findings suggest that ZEA regulates the expression of key factors of the Keap1-Nrf2 signaling pathway in the duodenum, which enables resistance to ZEA-induced oxidative stress. Further studies are needed to examine the effects of ZEA induced oxidative stress on other tissues and organs in post-weaning gilts.

Zearalenone-Promoted Follicle Growth through Modulation of Wnt-1/ß-Catenin Signaling Pathway and Expression of Estrogen Receptor Genes in Ovaries of Postweaning Piglets.

Feedstuffs are severely contaminated by zearalenone (ZEA) worldwide. A specific dietary level of ZEA could cause malformations of the reproductive organs of sows, false estrus, decreased litter size, and abortion. However, the underlying mechanisms are still not clear. The objectives of the present study were to assess the effects of ZEA on morphology, distribution, and expression of estrogen receptors (ERα and ERß) in the ovaries of postweaning piglets. Furthermore, the relationship between ERs/glycogen synthase kinase (GSK)-3ß-dependent pathways mediated by ZEA and the Wnt-1/ß-catenin signaling pathway was examined. Forty healthy weaning piglets were allocated to the following four treatment groups: piglets fed with basal diet only (control), and ZEA0.5, ZEA1.0, and ZEA1.5, which were fed basal diets supplemented with ZEA at 0.5, 1.0, and 1.5 mg·kg-1, respectively. Then, the expression of GSK-3ß, ERα, ERß, and Wnt-1/ß-catenin were examined histomorphologically and immunohistochemically. Results showed that the proportion of primordial follicles (PrF's) decreased ( p < 0.001) but that of atretic primordial follicles (APFs) increased ( p < 0.001) with increasing dietary ZEA levels. More interestingly, the immunopositivity of ERß in the ovaries was stronger than that of ERα with the same treatment. The relative mRNA and protein expression levels of ERα, ERß, Wnt-1, ß-catenin, and GSK-3ß in the ovaries of postweaning gilts increased linearly ( p < 0.05) as dietary ZEA concentrations increased. Moreover, the accumulation of Wnt-1 and ß-catenin in the ovaries indicated that ZEA activated the Wnt-1/ß-catenin pathway, mediated by ERs/GSK-3ß. Our results strongly suggested that ovarian follicles in the ZEA (0.5-1.5 mg·kg-1)-treated groups were highly proliferative state, indicating that ZEA promoted ovarian development. The results also suggested that ZEA activates the ERs/GSK-3ß-dependent Wnt-1/ß-catenin signaling pathway, indicating its important role in accelerating development of the ovaries.

Effects of zearalenone on the localization and expression of the growth hormone receptor gene in the uteri of post-weaning piglets.

OBJECTIVE: In this study, we investigated the adverse effects of dietary zearalenone (ZEA) (0.5 to 1.5 mg/kg diet) on the localization and expression of the growth hormone receptor (GHR) in the uteri of post-weaning gilts and explored alternative mechanism of the reproductive toxicity of ZEA on piglets. METHODS: A total of forty healthy piglets (Duroc×Landrace×Large White) aged 28 d were selected for study. Piglets were transferred to single cages after 10 days' adaptation on an obstetric table. The animals were allocated to one of four treatments: a normal basal diet supplemented with 0 (Control), 0.5 (ZEA0.5), 1.0 (ZEA1.0), or 1.5 (ZEA1.5) mg/kg purified ZEA, and fed for 35 d after the 10-d adaptation. Analyzed ZEA concentrations in the diets were 0, 0.52±0.07, 1.04±0.03, and 1.51±0.13 mg/kg, respectively. At the end of the feeding trial, piglets were euthanized after being fasted for 12 h. Two samples of uterine tissue from each pig were rapidly collected, one of which was stored at -80°C for analysis of the relative mRNA and protein expression of GHR, and the second was promptly fixed in Bouin's solution for immunohistochemical analysis. RESULTS: The relative weight of the uteri and thickness of the myometrium and endometrium increased linearly (p<0.001) and quadratically (p<0.001) with an increasing level of ZEA. The results of immunohistochemical analysis indicated that GHR immunoreactive substance was mainly localizated in the cytoplasm of uterine smooth muscle, glandular epithelial, luminal epithelial, stromal, and vascular endothelial cells. In contrast, nuclear staining was rarely observed. The immunoreactive integrated optic density of GHR in the myometrium, luminal epithelium, glandular epithelium, and whole uteri of weaning gilts increased linearly (p<0.001) and quadratically (p<0.05) with an increasing level of ZEA. The mRNA and protein expression of GHR in the uteri of weaning gilts increased linearly (p<0.001) and quadratically (p<0.05) with an increasing level of ZEA. CONCLUSION: In conclusion, ZEA at a concentration of 0.5 mg/kg was sufficient to significantly thicken the myometrium and endometrium, and at a concentration of 1.0 mg/kg induced a high level of GHR expression to promote growth and development of the uteri. This revealed an alternative molecular mechanism whereby ZEA induces growth and development of the uteri and provides a theoretical basis for the revision of Chinese feed hygiene standards.

In vitro study of effects of emulsified oil on broiler feed quality.

An experiment was conducted to compare effects of emulsified soybean oil and non-emulsified soybean oil on the quality of broiler feed differing in the feed type and the broiler feeding stage in vitro. A 2 × 2 × 3 factorial arrangement was designed with two fat sources (soybean oil and emulsified oil), two feed types (mash and pellet) and three broiler feeding stages (starter, grower and finisher). Four samples of feeds were collected from each combination of factors at the beginning of the experiment and stored at 20°C. Subsamples were taken at 15-day intervals to determine the moisture content, peroxide value (PV), acid value (AV) and the total fungal count over a 45-day period; weight loss percentage was determined by weighting the samples at days 0, 15, 30 and 45; fines percentage in pellets was only determined at day 0. The emulsified oil reduced (P < 0.05) the fines percentage, increased (P < 0.05) the moisture content, decreased (P < 0.05) the weight loss percentage and PV, did not affect (P > 0.05) the AV and the total fungal count. Results showed that the emulsified oil decreased weight loss, increased pelletability, moisture content and oxidation stability without affecting fungal growth.