Effects of stevia extract on production performance, serum biochemistry, antioxidant capacity, and gut health of laying hens.

In the present study, we aimed to elucidate the effects of stevia extract on production performance, serum immune indexes, intestinal structure, and cecum microbial structure. We randomly divided eight hundred 46-wk-old Roman hens into 5 groups, with 8 replicates in each group and 20 chickens in each replicate. The control group was fed a basal diet, whereas the 4 experimental groups were fed 50, 100, 200, and 400 mg/kg stevia extracts. The study period was 24 wk. The addition of different concentrations of the stevia extract to the diet resulted in significant secondary changes in the egg production rate at 1 to 12 wk (P < 0.05). Furthermore, the addition of 50 and 100 mg/kg stevia extract to the diet significantly increased serum IgM and IgG levels in laying hens (P < 0.05) but linearly decreased serum IL-1ß levels (P < 0.05). Serum T-SOD activity linearly increased (P = 0.057); however, serum biochemical indexes showed no significant differences. Stevia extract tended to increase the ratio of the duodenal villi height to the depth of the crypt (P = 0.067), with no obvious lesions in the duodenum, jejunum, and ileum. In addition, stevia extract increased the relative abundance of species at the phylum level, with the abundance of Bacteroides and Firmicutes exhibiting significant secondary changes (P < 0.05). The ACE and Chao1 indexes suggested that stevia extract addition significantly increased the alpha diversity of cecum microorganisms in laying hens. Furthermore, NMDS analysis based on operational taxonomic units revealed that stevia extract addition increased the beta diversity of cecum microorganisms in laying hens. Adding a certain amount of stevia extract to feed can improve the production performance, immune ability, and intestinal health of laying hens to some extent, and we recommend an effective level of 200mg/kg of stevia extract for laying hen diets.

The improving effect of soybean isoflavones on ovarian function in older laying hens.

Emerging evidence suggests an association between estrogen levels and reduced egg-laying performance as the layer became old. Since soy isoflavones (SF) have estrogen-mimic effects, whether it can enhance production performance and ovarian function of older layers is still not known. A total of 160 Lohmann pink layers (66-wk-old) were used in a 2 × 2 factorial design, which included 2 egg-laying levels [low (76.89 ± 1.65%; LOW) and normal (84.96 ± 1.01%; NOR)] and 2 different dietary groups [0 mg/kg SF, 20 mg/kg SF] were used. The results showed the NOR group had higher egg-laying rate, egg mass, and feed efficiency during the all phases (P(laying) < 0.05). The unqualified egg rate was lower in NOR group (9-12 wk, 1-12 wk) (P(laying) < 0.05). Dietary supplementation with SF increased the egg-laying rate and feed efficiency (5-8 wk, 9-12 wk, 1-12 wk), increased egg mass (9-12 wk, 1-12 wk) (P(SF) < 0.05). The NOR layers presented higher eggshell quality (redness, yellowness, brightness, eggshell ratio) at 12 wk (P(laying) < 0.05). Eggshell quality was found to be improved by SF (eggshell strength and eggshell thickness), egg albumen quality (higher albumen height and Haugh unit) at 12 wk (P(SF) < 0.05). Supplementing with SF led to an increase in eggshell strength in LOW group (P(laying*SF) < 0.05). The higher serum lever of glucose (GLU) and lower serum lever of follicle stimulating hormone (FSH) were in NOR group (P(laying) < 0.05). Supplementing SF in diets increased serum of estradiol (E2) and insulin-like growth factors-1 (IGF-1), decreased serum of FSH (P(SF) < 0.05). The NOR layers presented lower estrogen receptor α (ERα), estrogen receptor ß (ERß), B lymphoma 2 associated X protein (Bax), cytochrome c (Cytc), interleukin 6 (IL-6), caspase3, caspase9, IKKα, P50, and P65 expression in the ovary (P(laying) < 0.05). Dietary SF supplementation decreased the anti-Müllerian hormone receptor (AMHR), Bax, caspase3, caspase9, Cytc, IL-6, IKKα, P50, P65 expression in the ovary (P(SF) < 0.05). These findings indicated that layers with NOR group had higher production performance, egg quality, and ovarian function, while dietary supplementation with SF improved production performance and ovarian function by reducing inflammation and apoptosis-related genes expression in ovary.

Effects of dietary theabrownins on production performance, egg quality, and ovarian function of laying hens with different ages.

This experiment was conducted to investigate the effect of theabrownins (TB) on production performance, egg quality, and ovarian function of laying hens at different ages. A total of 240 Lohmann laying hens were assigned in a 2 × 2 factorial design, which encompassed 2 layers ages (47-wk-old and 67-wk-old) and 2 dietary levels of TB (0 and 100 mg/kg) for 12 wk. Results showed that older layers had lower laying rate, egg mass, and higher feed-to-egg ratio (F/E), egg weight and unqualified egg rate than the younger layers (P(AGE) < 0.01) during all the experimental period. The effect of TB was found to increase egg laying rate and feed efficiency during 5 to 8 wk, 9 to 12 wk and the overall phases and decreased unqualified egg rate during 1 to 4 wk and the overall phases (P(TB) ≤ 0.05). The eggshell quality (strength, thickness), albumen quality (albumen height and Haugh unit) of eggs from older layers were decreased during overall phases (P(AGE) ≤ 0.05). TB increased eggshell strength during all phases and enhanced eggshell thickness at the end of wk 4 and 8 and increased albumen height and Haugh unit at the end of wk 8 and 12 of older layers (P(Interaction) ≤ 0.05). In addition, TB also increased egg quality of older layers after 14 d storage. A decrease in the serum concentration of progesterone, melatonin, follicle stimulating hormone, estradiol was observed in the older compared to the younger ones (P(AGE) < 0.05), while the increase in serum concentration of progesterone, melatonin, anti-Müllerian hormone (AMH) were more emphasized when older hens received TB supplemented diet (P(Interaction) < 0.05). The older layer demonstrated lower the concentration of glutathione (GSH) (P(AGE) < 0.05). And the activity of glutathione-s-transferase (GST) was significantly decreased in layers under 67-wk-old (P(AGE) <0.05). The increase in concentration of GSH and the decrease in concentration of malondialdehyde (MDA) were more pronounced when TB were supplemented in 67-wk-old layers (P(Interaction) ≤ 0.05). Layers at 67-wk-old had lower mRNA expression of Heme oxygenase 1 (HO-1) (P(AGE) < 0.01) in ovary. Dietary TB supplementation upregulated mRNA gene expression of HO-1, Nuclear factor E2 related factor 2 (Nrf2), Quinone oxidoreductase 1 (NQO1) (P(TB) < 0.01). Dietary TB upregulated mRNA expression of ovarian reproductive hormone receptor (estrogen receptor 1 [ESR1] and steroidogenic acute regulatory protein 1 [StAR1]]; P(TB) < 0.01). The results suggest feeding TB (100 mg/kg) could improve the egg production rate, egg quality, and antioxidant capacity of the ovary. Moreover, the effect of TB was more pronounced in older layers (64-wk-old vs. 47-wk-old).

Effect of benzoic acid, Enterococcus faecium, and essential oil complex on intestinal microbiota of laying hens under coccidia and Clostridium perfringens challenge.

The objective of this study was to investigate whether dietary supplementation with benzoic acid, Enterococcus faecium, and essential oil complex (BEC) could help laying hens recover from coccidia and Clostridium perfringens type A challenge. A total of 60 (35-wk-old) Lohmann-laying hens were randomly assigned to 3 experimental groups (10 replicates with 2 hens per replicate): I) control group (CON), II) challenge group (CC), and III) BEC group (2,000 mg/kg BEC). The total experimental period was 8 wk. The results shown that the challenge layers had lower egg-laying rate and average daily feed intake (ADFI) (P < 0.05), and addition of BEC after challenge increased egg-laying rate (P < 0.05). The content of propionic acid (PA) and butyric acid (BA) in short-chain fatty acid (SCFA) was significantly decreased by challenge (P < 0.05). CC and BEC groups had lower villus height to crypt depth ratio (V/C) and higher pathological scores in duodenum (P < 0.05), whereas the BEC group had lower pathological scores in jejunum when compared with the CC group (P < 0.05). The challenge increased the concentration of proinflammatory cytokines (IL-1ß and IL-6) (P < 0.05). An increase in the abundance of Bacteroidoes (genus), Bacteroidaceae (family), Bacteroidoes sp. Marseille P3166 (species), Bacteroidoes caecicola (species) was observed in the CC group, whereas the BEC group had higher abundance of Bacteroides caecigallinarum (species). The genera Faecalibacterium and Asterolplasma were positively correlated with egg-laying rate (r = 0.57, 0.60; P < 0.01); and the genera Bacteroides and Romboutsia were negatively correlated with egg-laying rate (r = -0.58, -0.74; P < 0.01). The genera Bacteroides, Lactobacillus, and Rombutzia were positively correlated with jejunal mucosa proinflammatory factor IL-1ß level (r = 0.61, 0.60, 0.59; P < 0.01), which were negatively correlated with genera Rikenbacteriaceae RC9, Faecalibacterium, and Olsenlla (r = -0.56, -0.57, -0.61; P < 0.01). There genera UCG.005 was positively correlated with proinflammatory factor IL-6 level in jejunal mucosa (r = 0.58; P < 0.01), which was negatively correlated with Rikenbacteriaceae RC9 (r = -0.62; P < 0.01). The experiment results revealed that the addition of BEC to the diet restored the production performance of the laying hens. In addition, supplementation of 2,000 mg/kg BEC modulated gut health by reducing gut damage scores and modulating microbial composition, thereby promoting recovery of laying hens after coccidia and Clostridium perfringens challenge.

Dietary 25-hydroxyvitamin D improves productive performance and intestinal health of laying hens under Escherichia coli lipopolysaccharide challenge.

The effect of 25-hydroxyvitamin D (25OHD) on the immune response of laying hens is not well elucidated. This study investigated the effects of 25OHD on egg production, egg quality, immune response, and intestinal health of laying hens challenged with Escherichia coli lipopolysaccharide (LPS). One hundred and sixty laying hens at 45 wk of age were randomly divided into 4 dietary treatments with 10 replicates of 4 birds. Hens were fed the corn-soybean based diets contained either 0 or 80 µg/kg 25OHD for 8 wks. At wk of 53 wk, birds of each dietary treatment were injected into the abdomen with 1.5 mg/kg body weight of either LPS or saline a day at 24-h intervals for continuous 7 d. LPS injection significantly decreased (PLPS < 0.05) egg laying rate, feed intake and feed efficiency; while the supplementation of 25OHD increased (PInteraction < 0.05) egg laying rate, feed efficiency and decreased (PInteraction < 0.05) the broken egg rate in layers under LPS injection. LPS challenge decreased (PLPS < 0.05) eggshell strength, eggshell thickness, albumen height and Haugh unit, while dietary 25OHD supplementation increased eggshell strength and eggshell thickness (P25OHD < 0.05). The serum proinflammatory factors [tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6)], endotoxin and diamine oxidase (DAO) levels were higher in layers under LPS challenge (PLPS < 0.05); whereas the dietary addition of 25OHD were shown to decrease (P25OHD < 0.05) serum IL-1ß and IL-6 concentration irrespective of LPS challenge and led to a higher serum 25OHD level and a reduction in endotoxin concentration in layers under LPS challenge (PInteraction < 0.05). The layers under LPS challenge had higher crypt depth and lower villus height/crypt depth (V/C) ratio in duodenum and jejunum (PLPS < 0.05), while feeding 25OHD were shown to have decreasing effect on crypt depth and increasing effect V/C ratio in layers under LPS challenge (PInteraction < 0.05). Layers under LPS challenge had lower mRNA expression of intestinal barrier associated proteins (claudin-1 and mucin-1) (PLPS < 0.05), while the addition of 25OHD up-regulated claudin-1 and mucin-1 expression (Pinteraction < 0.05). Lower antioxidant enzymes activities, including superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), glutathione peroxidase (GPx) and higher malondialdehyde (MDA) content in jejunum were found in layers challenged with LPS (P25OHD < 0.05). The effect of 25OHD reversed the effect of LPS on SOD, T-AOC, and MDA content (PInteraction< 0.05). These results suggest that supplementing 80 µg/kg 25OHD in diets may elevate laying performance and egg quality through the improvement of intestinal barrier function, antioxidant capacity, and decreased the proinflammatory cytokines levels in laying hens with Escherichia coli LPS challenge.

Improvement in ovarian function following fecal microbiota transplantation from high-laying rate breeders.

The underlying mechanism between the gut microbiota and reproductive function is not yet well-known. This study was conducted to investigate the effect of the administration of fecal microbiota transplantation (FMT) from highly laying rate donors on the cecal microbiota, intestinal health and ovarian function in broiler breeders. A total of 60 broiler breeders (53 wk of age) were selected by their laying rate [high (HP, 90.67 ± 0.69%; n = 10) and low (LP, 70.23 ± 0.87%; n = 20)]. The LP breeders were then be transplanted with fecal microbiota from HP hens (FMTHP; n = 10) or the same dosage of PBS (FMTCON; n = 10) for 28 d. The results revealed that FMT from HP donors increased egg-laying rate and serum hormone levels [17ß-estradiol (E2), anti-Müller hormone], also decreased proinflammatory cytokine levels (interleukin-6, interleukin-8, tumor necrosis factor-α) of LP breeders (P < 0.05). The FMTHP group breeders had higher villus height, villus height/crypt depth ratio, and upregulated mRNA expression of jejunum barrier-related gene (ZO-2 and mucin-2) and estrogen, follicle-stimulating hormone (FSH) and anti-Müller hormone (AMH) receptor genes (ESR1, ESR2, FSHR, AMHR) (P < 0.05) than FMTCON group. FMT from HP donors led to higher mRNA expression of Bcl2 and sirtuin1 (SIRT1), while it downregulated the proapoptotic genes (Bax, caspase-3, caspase-8, and caspase-9) mRNA expressions in ovary compared with the FMTCON breeders (P < 0.05), and this pattern was also observed in HP donors. Also, HP breeder had higher observed_species and alpha-diversity indexes (Chao1 and ACE) than FMTCON group, while FMTHP can increase observed_species and alpha-diversity indexes (Chao1 and ACE) than FMTCON group (P < 0.05). The bacteria enrichment of Firmicutes (phylum), Bacteroidetes (phylum), Lactobacillus (genus), Enterococcus (genus), and Bacteroides (genus) were increased by FMTHP treatment. The genera Butyricicoccus, Enterococcus, and Lactobacillus were positively correlated with egg-laying rate. Therefore, cecal microbiomes of breeders with high egg-laying performance have more diverse activities, which may be related to the metabolism and health of the host; and FMT from high-yield donors can increase the hormone secretion, intestinal health, and ovarian function to improve egg-laying performance and the SIRT1-related apoptosis and cytokine signaling pathway were involved in this process.

Effects of Dietary Zinc Deficiency on Skin Breaking Strength and Fatty Acid Composition in Broiler Chickens and Pekin Ducks.

This study is aimed at investigating the effect of dietary zinc deficiency (ZnD) on skin breaking strength and skin chemical and fatty acid composition in broiler chickens and Pekin ducks. A total of 200 1-day-old male broiler chickens and 200 1-day-old male ducklings were used in a 2 × 2 factorial design and randomly allocated to 4 treatments with 10 replicated cages of 10 birds per cage. Diets containing zinc at 84.77 mg/kg and 20.42 mg/kg were regarded as the control diet and zinc-deficient diet, respectively. The results showed the following: (1) dietary ZnD decreased (P < 0.05) the breast skin weight (day 21), breast skin index (day 21), skin fat content (day 7), and skin Zn content (days 7, 14, and 21) of ducks, but only increased (P < 0.05) the skin fat content of broiler chickens at 7 days of age; ducks had a higher (P < 0.05) breast skin weight, breast skin index, and skin breaking strength as well as a lower skin fat content (days 7 and 14) than those in broiler chickens. (2) Dietary ZnD decreased the content of myristic acid (day 21) and increased the content of oleic acid (day 7) content in the skin of ducks and increased the palmitic acid (day 7) content in the skin of broiler chickens (P < 0.05) and increased the MUFA (day 7) content in the skin and the atherogenic index (day 21) in ducks. The contents of myristic acid (day 21), stearic acid (day 21), and oleic acid (days 7, 14, and 21) in the skin of broiler chickens were lower (P < 0.05) than those in ducks of the same age. In conclusion, using skin weight, skin index and skin MUFA content as criteria, the results indicated that meat ducks were more sensitive to dietary ZnD than broiler chickens. Using skin fat content as criterion, the results indicated that broiler chickens were more sensitive to dietary ZnD than meat ducks.

Determination of Time Progression and Sensitive Biomarkers of Maternal Zinc Depletion in Broiler Chickens and Pekin Ducks Fed a Zinc-Deficient Diet.

Two experiments were performed to assess maternal zinc (Zn) depletion in broiler chickens and Pekin ducks fed a Zn-deficient diet. The time of Zn depletion was assessed based on growth performance, and sensitive biomarkers were determined based on tissue Zn content via a linear regression model. A total of 200 1-day-old male broiler chickens (experiment 1) and 200 1-day-old male Pekin ducks (experiment 2) were randomly allocated to 2 diets with 10 replicate cages (10 birds/cage). The two diets were a zinc-deficient diet (ZnD, 20.42 mg Zn/kg) and a control zinc diet (CON, 84.77 mg Zn/kg). In experiment 1, compared to CON, ZnD decreased (P < 0.05) the body weight (days 7, 14, and 21), body weight gain, feed intake (days 1-7, 1-14, and 1-21), and the Zn content of plasma (days 7 and 21), pancreas (days 7, 14, and 21), and tibia in broiler chickens. The R2 of a linear model was greater at day 7 than at day 14 or day 21 for pancreatic Zn content in broiler chickens. In experiment 2, compared to CON, ZnD also decreased (P < 0.05) the body weight (days 7, 14, and 21), body weight gain (days 1-7, 1-14, and 1-21), and feed intake (days 1-14 and 1-21) and increased (P < 0.05) the feed-to-gain ratio (days 1-7 and 1-14) in ducks. Compared with CON, ZnD reduced (P < 0.05) the Zn content of the pancreas (days 7, 14, and 21), tibia (days 7, 14, and 21), and skin (days 14 and 21) and increased (P < 0.05) the Zn content of the plasma (day 21) and skin (day 7) in ducks. The R2 of a linear model was greater at day 7 than at days 14 or 21 for skin Zn content in ducks. The results indicated that the maternal Zn was depleted by 7 days of age in both birds; the sensitive biomarker for broiler chickens is pancreatic Zn content, and for ducks, it is skin Zn content.

Comparison of zinc bioavailability in zinc-glycine and zinc-methionine chelates for broilers fed with a corn-soybean meal diet.

The objective of this study was to compare the bioavailability of zinc (Zn) from zinc-glycine (Zn-Gly) and zinc-methionine (Zn-Met) as compared with zinc sulfate (ZnSO4) used as a standard in broilers. A total of 1,200 one-day-old male broilers (Cobb 500) were randomly allotted to one of 10 treatments with eight replicate cages of 15 birds each. The broilers were fed a corn-soybean meal basal diet (containing 26.46 mg Zn/kg; control) or the basal diet added with 40, 80, and 120 mg Zn/kg as Zn-Gly, Zn-Met, or ZnSO4 for 14 days. The relative bioavailability value (RBV) was calculated based on multiple linear regression slope ratios of Zn concentrations in tibia and pancreas, pancreas metallothionein (MT) concentration, and pancreas MT mRNA abundance on added Zn intake. When comparing the control with all Zn-supplemented treatments, Zn addition did not significantly affect average feed intake and bodyweight gain during days 1-14 (p > 0.10). However, Zn concentrations in the tibia, pancreas, and liver and pancreas MT concentration and MT mRNA abundance increased in all Zn-supplemented treatments compared with the control (p < 0.05), and these indices increased linearly (p < 0.001) with increasing added Zn levels on days 7 and 14. The RBV of Zn as Zn-Met was similar to that as Zn-Gly or ZnSO4 (p > 0.40) on days 7 and 14, based on tibia and pancreas Zn. In contrast, on days 7 and 14, the RBVs of Zn were in the following order: Zn-Met > Zn-Gly > ZnSO4 (p < 0.05), based on pancreas MT concentration. The bioavailable Zn from Zn-Met was 1.20 or 1.25 times that from Zn-Gly on day 7 or 14, respectively, evaluated by pancreas MT content. The RBV of Zn as Zn-Met was similar to that as Zn-Gly or ZnSO4 on day 7, whereas it was higher than that as Zn-Gly or ZnSO4 on day 14, based on pancreas MT mRNA abundance. In conclusion, Zn-Met had higher bioavailable Zn than Zn-Gly for the starter broilers fed with the corn-soybean meal diet, using pancreas MT concentration as the response criterion.

Effects of coated sodium butyrate on performance, egg quality, nutrient digestibility, and intestinal health of laying hens.

This study determined the effects of coated sodium butyrate (CSB) on production performance, egg quality, nutrient digestibility, and intestinal health of laying hens. We divided a total of 800 Lohmann laying hens, aged 51 wk, into 4 treatment groups: 0 (CON), 300 (CSB1), 500 (CSB2), and 800 (CSB3) mg/kg of CSB. Each group comprised 20 birds, with 10 replicates set. A 12-wk monitoring process was conducted for each laying hen. Compared to CON, dietary supplementation of CSB did not affect the average daily feed intake or the egg weight. The CSB3 group demonstrated a linear increase in the production performance (P < 0.05), with decreased feed conversion ratio (P < 0.05). CSB2 and CSB3 exhibited markedly elevated egg mass (P < 0.05). The CSB supplementation markedly enhanced the yolk color (P < 0.05). CSB1 improved the digestibility of dry matter (P = 0.029). No significant differences were observed among dietary treatments in the duodenal morphology (P > 0.05). The three dosages of CSB reduced the crypt depth (P < 0.05) in the jejunum, whereas CSB3 exhibited an increase in the villus height (VH; P = 0.048). The CSB3 group showed a markedly elevated ileal VH (P = 0.011). CSB supplementation significantly increased the butyric acid content in the cecum (P = 0.009). The hens fed on the 800 mg/kg CSB diet showed a significant increase (P = 0.029) in butyric acid content in the ileum. The CSB3 group showed an elevation in microbial diversity (P < 0.05). Additionally, at the phylum level, the CSB3 increased the enrichment of Bacteroidetes, the CSB2 increased Firmicutes, and the abundance of Deferribacteres was increased in CSB2 and CSB3 groups (P < 0.05). An enrichment of Muribaculaceae (family) was observed in the CSB3 group. In conclusion, dietary supplementation of CSB improved production, yolk color, intestinal morphology, butyrate content, and microbial composition in laying hens.

Dietary resveratrol improved production performance, egg quality, and intestinal health of laying hens under oxidative stress.

Resveratrol (RV) is associated with protection against oxidative stress to improve health, however the effect of RV in layers under oxidative stress (OS) is limited. The objective of this experiment was to investigate the negative effect of OS and protective effects of RV against OS in laying hens. 40 Lohmann layers (25-wk-old; BW = 1.44±0.10 kg) were allocated to four treatments in a 2 × 2 factorial arrangement with either RV (0 or 600 mg/kg) or intraperitoneal injection of tert-butyl hydroperoxide (tBHP) (0 or 800 µmol/kg BW) for 31 days. The results shown that the hens challenged with tBHP presented lower egg-laying rate, feed intake, feed efficiency and higher defective egg rate (P(tBHP)<0.05). The RV were also observed to attenuated egg laying rate and feed intake reduction together with decreased broken egg rate under t-BHP challenge (P(Interaction)≤0.01). The tBHP challenged layer demonstrated lower intestinal morphology (villus height in duodenum and jejunum), lower antioxidant enzymes activities [total superoxidase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC)], and glutathione (GSH) levels and higher malondialdehyde (MDA) level] (P(tBHP)<0.05). Dietary RV increased jejunal SOD, GSH-Px and T-AOC activities, and reduced MDA concentration (P(RV) ≤0.05). Layers under tBHP challenge up-regulated mRNA expression of pro-inflammatory cytokine [interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)] and nuclear factor NF-κB (P(tBHP)<0.05) in jejunum. Dietary RV supplementation down-regulated mRNA gene expression of IL-1ß, IL-6, TNF-α and NF-κB (P(RV) ≤0.05). Dietary RV up-regulated mRNA expression of jejunal barrier-related proteins (claudin-1, claudin-2, mucin-1, and occludin) and ovarian reproductive hormone receptor [steroidogenic acute regulatory protein (StAR), androgen receptor (AR), estrogen receptor 1 (ESR1), and activin a receptor type 1 (ACVR1)] (P(RV) ≤0.05). Overall, the results indicate that tBHP induced oxidative stress to result in reducing production performance, intestinal health and induced ovarian inflammation; whereas dietary RV was able to maintain intestinal health and mitigate the negative impact of tBHP challenge on production performance and ovarian function.

Alleviating effect of dietary supplementation of benzoic acid, Enterococcus faecium and essential oil complex on coccidia and Clostridium perfringens challenge in laying hens.

The purpose of this experiment is to explore the effects of dietary supplementation of benzoic acid, Enterococcus faecium, and essential oil complex (BEC) on coccidia and Clostridium perfringens challenge in laying hens. A total of 80 Lohmann gray laying hens (35 wk old) were allocated to 4 treatments in a 2 × 2 factorial arrangement with the main effects of Clostridium perfringens type A (CP) and coccidia challenge (with or without challenge) and 2 BEC levels (0 and 1,000 mg/kg). The total experimental period was 6 wk. The results showed that: the challenge group significantly decreased the laying rate and average daily feed intake (ADFI) of laying hens (PChallenge < 0.01). The BEC + challenge group significantly increased the laying rate and decreased the feed conversion ratio (FCR) of laying hens (PBEC < 0.05). The challenge significantly decreased the thickness, strength, and relative weight of eggshell (PChallenge < 0.05). The BCE + challenge group significantly increased the relative weight and strength of the eggshell (PBEC < 0.05). The challenge significantly increased the crypt depth of the duodenum, jejunum and ileum, and decreased the villus-to-crypt ratio (V/C) (PChallenge < 0.01). The BEC + challenge group decreased the crypt depth of the duodenum and jejunum, and increased the V/C of the duodenum (PBEC < 0.01). The pathological scores of duodenum and jejunum of the challenge group were significantly higher than other groups (PChallenge < 0.01), while the BEC + challenge group had lower pathological scores of jejunum (PBEC < 0.01). The challenge significantly decreased the mRNA expression of Occludin, Mucin-2, Zonula occluden-1 (ZO-1) (Pchallenge < 0.05); whereas the BEC group significantly increased the expression of Occludin, Mucin-2, and Claudin-1 mRNA (PBEC < 0.05). The challenge significantly increased the level of interleukin 1ß (IL-1ß) in the jejunum (PChallenge < 0.05). Taken together, adding BEC to the diet can improved production performance and egg quality of layers, by protecting intestinal health against Clostridium perfringens type A (CP) and coccidia challenge.

Effects of Dietary Glucose Oxidase Supplementation on the Performance, Apparent Ileal Amino Acids Digestibility, and Ileal Microbiota of Broiler Chickens.

This study aimed to investigate the effects of glucose oxidase (GOD) supplementation on growth performance, apparent ileal digestibility (AID) of nutrients, intestinal morphology, and short-chain fatty acids (SCFAs) and microbiota in the ileum of broilers. Six hundred 1-day-old male broilers were randomly allotted to four groups of 10 replicates each with 15 birds per replicate cage. The four treatments included the basal diet without antibiotics (Control) and the basal diet supplemented with 250, 500, or 1000 U GOD/kg diet (E250, E500 or E1000). The samples of different intestinal segments, ileal mucosa, and ileal digesta were collected on d 42. Dietary GOD supplementation did not affect daily bodyweight gain (DBWG) and the ratio of feed consumption and bodyweight gain (FCR) during d 1-21 (p > 0.05); however, the E250 treatment increased DBWG (p = 0.03) during d 22-42 as compared to control. Dietary GOD supplementation increased the AIDs of arginine, isoleucine, lysine, methionine, threonine, cysteine, serine, and tyrosine (p < 0.05), while no significant difference was observed among the GOD added groups. The E250 treatment increased the villus height of the jejunum and ileum. The concentrations of secreted immunoglobulin A (sIgA) in ileal mucosa and the contents of acetic acid and butyric acid in ileal digesta were higher in the E250 group than in the control (p < 0.05), whereas no significant differences among E500, E1000, and control groups. The E250 treatment increased the richness of ileal microbiota, but E500 and E100 treatment did not significantly affect it. Dietary E250 treatment increased the relative abundance of Firmicutes phylum and Lactobacillus genus, while it decreased the relative abundance of genus Escherichina-Shigella (p < 0.05). Phylum Fusobacteria only colonized in the ileal digesta of E500 treated broilers and E500 and E1000 did not affect the relative abundance of Firmicutes phylum and Lactobacillus and Escherichina-Shigella genera as compared to control. These results suggested that dietary supplementation of 250 U GOD/kg diet improves the growth performance of broilers during d 22-42, which might be associated with the alteration of the intestinal morphology, SCFAs composition, and ileal microbiota composition.

Dietary tributyrin improves reproductive performance, antioxidant capacity, and ovary function of broiler breeders.

The objective of this experiment was to investigate the influence of dietary tributyrin on reproduction performance and ovary function of broiler breeders with different egg laying rate. Two hundred fifty-six AA broiler breeders (48-wk-old) were allocated to 4 treatment in a 2 × 2 factorial arrangement with the main effects of tributyrin supplementation (0 and 1,000 mg/kg tributyrin [TRI]) and 2 egg laying rate levels (average [AR, 81.01 ± 0.79%] and low [LR, 70.98 ± 0.95%]). The results shown that the LR breeders presented higher egg weight, but lower egg laying rate, qualified egg rate and feed efficiency than the AR breeders (P(laying) < 0.05). Also, the superoxidase dismutase (SOD) activity in magnum was lower while malondialdehyde (MDA) was higher in ovary and magnum of LR breeders than that in the AR breeders (P(laying) < 0.05). Dietary supplementation with tributyrin significantly enhanced egg weight (P(TRI) < 0.05), increased albumen height as well as Haugh unit (HU) in AR breeders (P(interaction) < 0.05), and also had higher total antioxidant capacity (T-AOC) and lower MDA in ovary (P(TRI) < 0.05). The cell apoptosis rate and proapoptosis related gene expression (caspase 8, 9 and Bax) in the ovary of LR breeders was higher, while anti-apoptosis related gene (Bcl-2) expression were lower in LR breeders when compared with the AR breeders (P(laying) < 0.05). Dietary supplementation with tributyrin decreased the cell apoptosis rate and downregulated caspase 9 expression in LR breeders (P(Interaction) < 0.05), up-regulated the Bcl-2 expression in both 2 breeders (P(TRI) < 0.05). These findings suggest that the breeders with lower egg laying rate also characterized by deteriorate ovary function indicated by lower antioxidant capacity and higher cell apoptosis rate. Dietary supplementation with tributyrin increased egg albumen quality, decreased ovarian proapoptosis related gene expression to improve reproductive tract function; and the positive effect on egg albumen quality is more pronounced in average reproductive breeders.

Dietary 25-hydroxyvitamin D improves intestinal health and microbiota of laying hens under high stocking density.

The high stocking density is a major stress factor that adversely affects the health and performance of poultry. Therefore, the object of this study was conducted to explore whether dietary 25-hydroxyvitamin D (25-OH-D3) could improve gut health of laying hens reared under high stocking density. A 2 × 2 factorial design was used in this 16-week study, in which 800 45-week-old Lohmann laying hens were allocated into two levels of dietary 25-OH-D3 levels (0 and 69 µg/kg) and two rates of stocking densities [506 (low density, LD) and 338 (high density, HD) cm2/hen]. Compared with the layers with LD, the layers with HD had lower crypt depth in duodenum (P(Density) < 0.05), lower short chain fatty acid (propionic and butyric acid) contents in cecum (P(Density) < 0.05), and lower mRNA expression of intestinal barrier associated protein (claudin-1, mucin-1 and mucin-2). Exposed layer to HD also led to lower intestinal antioxidative capacity [superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), and higher malondialdehyde (MDA) content] in small intestine (P(Density) < 0.05), lower bacterial abundance of Bacteroidetes (phylum), Spirochaetes (phylum) and Bacteroides (genus; P(Density) < 0.05), higher bacterial enrichment of Lactobacillaceae (genus) and Firmicutes/Bacteroidetes ratio (P(Density) < 0.05) in cecum. Dietary 25-OH-D3 increased the villus height in duodenum and jejunum (P(25-OH-D3) < 0.05), decreased Chao 1 and ACE indexes in cecum (P(25-OH-D3) < 0.05), and it also up-regulated the mRNA expression of claudin-1, mucin-1 and mucin-2 (P(25-OH-D3) < 0.05). Layers treated with 25-OH-D3 led to an enhanced antioxidative enzyme activity of CAT (P(25-OH-D3) < 0.05). Additionally, the effect of 25-OH-D3 reversed the effect of HD on T-AOC and MDA content (P(Interaction) < 0.05). In HD layers, 25-OH-D3 administration decreased the enrichment of Bacteroidetes (phylum), increased Firmicutes (phylum), and Firmicutes/Bacteroidetes ratio (P(Interaction) < 0.05). These results suggest that supplementing 25-OH-D3 in diets may elevate gut health through the improvement of intestinal barrier function, antioxidant capacity and cecal microbiota composition in laying hens with high stocking density.

Effects of Maternal and Progeny Dietary Vitamin E on Growth Performance and Antioxidant Status of Progeny Chicks before and after Egg Storage.

Two trials were conducted to investigate the effects of maternal and progeny dietary vitamin E (VE) supplementation on the growth performance and antioxidant status of offspring before and after egg storage. A total of 576 75-week-old Ross 308 breeder hens were assigned to three dietary VE treatments (100, 200, and 400 mg/kg) with 6 replicates of 32 hens for 12 weeks. Two trials were conducted with offspring hatched from eggs laid at weeks 9 and 12 of breeder feeding trial, respectively. Trial 1 was conducted by a 3 × 2 factorial arrangement of treatments with three levels of maternal dietary VE (100, 200, and 400 mg/kg) and two levels of progeny dietary VE (0 and 35 mg/kg). Trial 2 was conducted with three maternal dietary VE treatment (100, 200, and 400 mg/kg), and chicks were hatched from eggs stored for 14 d and received the same progeny diet with no addition of VE. Results showed that in trial 1, maternal (100, 200, and 400 mg/kg) and progeny (0 and 35 mg/kg) dietary VE supplementation did not affect the growth performance of offspring hatched from unstored eggs (p > 0.05). In trial 2, in the case of long-term egg storage, maternal dietary VE supplementation of 200 and 400 mg/kg increased the body weight (BW) of 21- and 42-d-old offspring and the body weight gain (BWG) of offspring from 1 to 21 d (p < 0.05), and decreased the feed conversion ratio (FCR) of offspring from 1 to 21 d (p < 0.05) compared to 100 mg/kg VE. As the maternal dietary VE levels increased, the liver and serum antioxidant status of offspring enhanced (p < 0.05). In conclusion, maternal dietary VE supplementation of 200 or 400 mg/kg could improve the growth performance and anti-oxidant status of offspring hatched from stored eggs, but not for that of offspring hatched from unstored eggs. The suitable VE level for the broiler breeder diet was 400 mg/kg in the case of long-term egg storage.

Differential analysis of gut microbiota and the effect of dietary Enterococcus faecium supplementation in broiler breeders with high or low laying performance.

The difference in microbiota was examined for breeders with different egg-laying rates, and the impact of dietary Enterococcus faecium (EF) was also determined in the present study. A total of 256 Arbor Acres broiler breeders (48-wk-old) were used in a 2 × 2 factorial design, which encompassed 2 egg-laying rate levels [average (average egg laying: AP, 80.45 ± 0.91%) and low (lower egg laying: LP, 70.61 ± 1.16%)] and 2 different dietary groups [control (no additive), 6 × 108 cfu/kg EF]. The results showed that the AP breeders presented a lower egg weight, feed conversion ratio, abdominal fat rate, and serum leptin level (P(laying) ≤ 0.05) as well as a higher egg-laying rate (P(laying) < 0.01) than the LP breeders. Dietary supplementation with EF improved the egg weight (P(EF) = 0.03) and had a higher concentration of follicle-stimulating hormone (FSH) in the serum (P(EF) = 0.04). The relative expression of Caspase 9, Bax, AMHR, BMP15, and GATA4 in the ovary of AP breeders was lower, whereas the FSHR and BMPR1B expression was higher than that measured in LP breeders (P(laying) ≤ 0.05). LP increased the abundance of Bacteroidetes (phylum), Firmicutes (phylum), Bacteroidia (class), Clostridia (class), Bacteroidales (order), Clostridiales (order), and Lachnospiraceae (family), whereas the AP promoted the enrichment of Proteobacteria (phylum) and Gammaproteobacteria (class) (P(laying) < 0.05). The genera Bacillus, Rhodanobacter, and Streptomyces were positively correlated with the egg-laying rate and BMPR1B expression (P < 0.05) but negatively correlated with the abdominal fat rate (P < 0.05) and Caspase 9 (P < 0.05). These findings indicate that the low reproductive performance breeders had lower microbiota diversity and higher Firmicutes, which triggers the energy storage that led to higher fat deposition. Besides, increases in the abdominal fat rate, leptin level, and apoptosis (Caspase 9, Bax) and reproduction-related gene (BMP15, AMHR, BMPR1B, and GATA4) expression would possibly be the potential mechanisms under which breeders have different reproductive performance. Dietary EF increased the egg weight and serum FSH level and decreased the Bacteroidetes (phylum) in low reproductive breeders.

The effect of dietary pectic oligosaccharide supplementation on intestinal health of broiler breeders with different egg-laying rates.

This study was conducted to explore whether dietary pectic oligosaccharide (POS) supplementation could improve gut health of broiler breeders with different egg-laying rates. A 2 × 2 factorial design was used in this study. Two hundred fifty-six Arbor Acres broiler breeders (48 wk of age), including 128 average egg-laying rate and 128 low egg-laying rate (LELR) birds, were randomly fed with the diets supplemented with or without 200 mg kg-1 of POS (n = 8). The trial lasted for 8 wk. Compared with average egg-laying rate broiler breeders, LELR broiler breeders had lower laying rate and qualified egg rate (P < 0.05), higher egg weight and feed conversion ratio (P < 0.05), higher malondialdehyde (MDA) levels in the jejunum (P < 0.05), higher IL-6 (P < 0.05) and tumor necrosis factor α (TNF-α) (P = 0.07) mRNA expressions in the jejunal mucosa, and lower microflora diversity in cecal digesta. Dietary POS supplementation increased egg weight of broiler breeders (P < 0.05), enhanced superoxide dismutase activity in the jejunum (P < 0.05), decreased MDA level in the jejunum (P < 0.05), upregulated zonula occluden 1 mRNA expression in the jejunal mucosa (P < 0.05), downregulated IL-6 and TNF-α mRNA expressions in the jejunal mucosa (P < 0.05), and regulated relative abundance of some microbiota (including the phylum and genus, P < 0.05). In addition, in LELR broiler breeders, POS administration enhanced villus height (P = 0.08) and ZO-2 mRNA expression (P = 0.09) in the jejunal mucosa, alleviated the increasing MDA level in the jejunum (P < 0.05) and IL-6 and TNF-α mRNA expressions in the jejunal mucosa (P < 0.05), and regulated relative abundance of some microbiota (including the phylum and genus, P < 0.05). These results suggest that supplementing POS in diets may elevate gut health via improvement of intestinal barrier function, antioxidant capacity, and microbiota composition in broiler breeders with different egg-laying rates.

Dietary apple pectic oligosaccharide improves reproductive performance, antioxidant capacity, and ovary function of broiler breeders.

Reproduction performance is one of the most important economic traits for the poultry industry. Intriguingly, apple pectic oligosaccharide (APO) could promote gastrointestinal function and immune function to improve performance; however, literature about APO on reproduction performance in breeders is limited. This study aimed to determine whether APO administration can improve reproduction performance and ovary function of broiler breeders with different egg laying rates. Two hundred and fifty six Arbor Acres broiler breeders (48-week-old) were used in a 2 × 2 factorial design with 2 egg laying rates (average [AR] and low [LR]) and 2 dietary levels of APO (0 and 200 mg/kg APO). Results showed that the LR breeders presented higher egg weight but lower egg laying rate, qualified egg rate, and feed efficiency than the AR breeders (P(laying) < 0.05). Also, the LR breeders had decreased serum Anti-Müllerian hormone, leptin, and antioxidant enzyme (superoxide dismutase, total antioxidant capacity) levels than the AR breeders (P(laying) ≤ 0.05). Dietary supplementation with APO improved egg weight, feed efficiency, as well as egg albumen quality (higher albumen height and Haugh unit) (P(APO) < 0.05), and decreased the concentration of pro-inflammatory cytokine levels (interleukin [IL]-1ß, IL-8) in serum (P(APO) ≤ 0.05). The apoptosis rate and pro-apoptosis-related gene expression (caspase 9 and Bax) in the ovary of LR breeders were higher, while the anti-apoptosis-related gene expression (Bcl-2, PCNA) was lower in LR compared with the AR breeders (P(laying) < 0.05). Dietary supplementation with APO decreased the caspase 9 and Bax expression in LR breeders (P(interaction) < 0.05), and increased the Bcl-2 and PCNA expression in the 2 breeders (P(APO) < 0.05). These findings indicate that breeders with a lower egg laying rate exhibit lower antioxidant capacity and high cell apoptosis in the ovary. Dietary supplementation with APO might improve albumen quality and antioxidant capacity, and decrease the inflammatory factors and ovary apoptosis-related genes expression to improve ovary function. Moreover, the effect of APO on decreasing ovarian pro-apoptosis-related gene expression was more pronounced in lower reproductive breeders.

Effect of benzoic acid on production performance, egg quality, intestinal morphology, and cecal microbial community of laying hens.

This study was conducted to determine the effects of supplemental dietary benzoic acid on production performance, egg quality, intestinal morphology, and intestinal microbiota of laying hens. A total of seven hundred twenty 45-wk-old Lohman pink-shell laying hens were randomly allocated to 3 dietary treatments: control (CON), diet supplemented with 1,000 mg/kg benzoic acid (BA1), and 2,000 mg/kg benzoic acid (BA2). Each treatment included 10 replicates of 24 hens; laying hens were monitored for 16 wk. Overall, the results indicate that benzoic acid supplementation had no effect on laying rate, feed intake, feed conversion ratio, and breaking rate; however, a decrease in egg weight (P < 0.01) was observed in the BA2 group. Albumen height and Haugh unit (HU) were also linearly increased in the BA1 and BA2 groups (linear effect, P < 0.05). An increase in duodenum villus height (V) (quadratic effect, P = 0.041) and crypt depth (C) (linear effect, P = 0.012) was observed in the BA2 group, whereas an increased jejunum C and decreased V/C (quadratic effect, P < 0.05) in the BA1 group. Moreover, an increase in ileum V and C (quadratic effect, P < 0.05) was observed in the BA1 group. Microbial richness and diversity were reduced in the BA2 group (P < 0.01). An increase in the abundance of Clostridia (class), Clostridiales (order), Ruminococcaceae (family), and Lachnospiraceae (family) was noted in the BA1 group, whereas an enrichment of Bacteroides caecicola (species) was observed in the BA2 group. The HU positively correlated with genus Sphaerochaeta and Enorma (r = 0.56, 0.56; P < 0.05) but negatively correlated with Romboutsia, Subdoligranulum, Helicobacter, and Mucispirillum (r = -0.58, -0.49, -0.48; -0.70; P < 0.05). In conclusion, dietary supplementation with benzoic acid had no effect on production performance, but it significantly improved egg quality. In addition, 1,000 mg/kg benzoic acid positively modulated intestinal health by improving intestinal morphology and enriching microbial composition.