Comparison of the effects of chlorogenic acid isomers and their compounds on alleviating oxidative stress injury in broilers.

The development of large-scale and intensive breeding models has led to increasingly prominent oxidative stress issues in animal husbandry production. Chlorogenic acid (CGA) is an important extract with a variety of biological activities. It is an effective antioxidant drug and shows different antioxidant capacities due to its different chemical structures. Therefore, it is a new research target to determine the proportion of chlorogenic acid isomers with high antioxidant activity to resist the damage caused by oxidative stress. In this experiment, the antioxidant activities of the chlorogenic acid monomer and its compounds were compared by a series of in vitro antioxidant indexes. Based on the above experiments, it was found that LB and LC have superior antioxidant abilities (P < 0.05). Subsequently, 300 healthy 1-day-old Arbor Acres (AA) male broilers with no significant difference in body weight (about 44 g) were randomly selected and randomly divided into 5 groups with 6 replicates in each group and 10 chickens in each replicate. One group was the control group, 1 group was the model group, and the remaining 3 groups were the experimental groups. At 37 d of age, animals in the control group were injected with normal saline, and animals in the other 4 groups were injected with 1 mL/kg 5% hydrogen peroxide (H2O2) through the chest muscle before the supplementation. The control group (control) and the model group (PC) were fed a standard diet. The remaining 3 groups included the CGA group, LB group (CIB), and LC group (CIC). In these groups, 50 g/t chlorogenic acid, LB compound, or LC compound were added to the basal diet, respectively, and the other feeding conditions remained consistent. The addition of the LB complex to the diet could significantly improve the growth performance and antioxidant performance of broilers (P < 0.05), upregulate the expression of Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway-related genes in liver and jejunum (P < 0.05), regulate the disordered intestinal flora, and alleviate the damage caused by oxidative stress. These results suggested for the first time that the LB complex exhibited superior effects in vitro and vivo.

Dimethylglycine Alleviates Metabolic Dysfunction-Associated Fatty Liver Disease by Improving the Circulating Estrogen Level via Gut Staphylococcus.

Our previous study screened out dietary 0.1% dimethylglycine (DMG), which had beneficial effects on egg production and fat deposition in laying hens during the late laying period. In this paper, it was further found that dietary DMG alleviated fatty liver disease and enhanced lipid deposited into the yolk while promoting hepatic lipid transport. There are intestinal estrogen-metabolizing bacteria (EBM) having ß-glucuronase (GUS) activity that regulates the content of circulating estrogen (E2) in mammals. There were 39 related bacteria found in laying hens, and DMG increased E2 in blood, Staphylococcus abundance among EBM and GUS activity in cecum chyme. Interfered in situ, Staphylococcus with GUS activity was proved the target bacteria for DMG. Furthermore, E2 could modify hepatic lipid deposition through promoting lipid transport by the steatosis LMH model. These perspectives confirm that DMG, mediated by Staphylococcus, alleviates the restriction of hepatic lipid transport due to reduced levels of E2 in laying hens.

Dietary pyrroloquinoline quinone improvement of the antioxidant capacity of laying hens and eggs are linked to the alteration of Nrf2/HO-1 pathway and gut microbiota.

Pyrroloquinoline quinone disodium (PQQ·Na2) has been considered a human food supplement for human health promotion with its antioxidant properties. To determine whether PQQ·Na2 had similar functions to improve the antioxidant ability of layers and eggs, 180 laying hens were fed with 0 or 0.4 mg/kg PQQ·Na2 diets. Supplementation with PQQ·Na2 increased the albumen height, Haugh unit of the eggs. PQQ·Na2 also led to a higher glutathione peroxidase (GSH-Px) concentration in plasma and a lower malondialdehyde (MDA) content in the liver and egg yolk. Similarly, liver gene and protein expression of nuclear factor erythroid 2-related 2 (Nrf2) and heme oxygenase 1 (HO-1) were up-regulated by PQQ·Na2. Moreover, PQQ·Na2 increased the abundance of Firmicutes, Microbacterium, Erysipelatoclostridium, Mailhella, Lachnospiraceae_UCG-010, and Herbaspirillum in gut. Overall, these results suggested PQQ·Na2 increased the antioxidant ability of layers and eggs which might be in connection with the activation of the Nrf2/HO-1 pathway and optimized gut microflora.

Probiotic Escherichia coli Nissle 1917 protect chicks from damage caused by Salmonella enterica serovar Enteritidis colonization.

As a foodborne pathogen of global importance, Salmonella enterica serovar Enteritidis (S. Enteritidis) is a threat to public health that is mainly spread by poultry products. Intestinal Enterobacteriaceae can inhibit the colonization of S. Enteritidis and are regarded as a potential antibiotic substitute. We investigated, in chicks, the anti-S. Enteritidis effects of Escherichia coli (E. coli) Nissle 1917, the most well-known probiotic member of Enterobacteriaceae. Eighty 1-d-old healthy female AA broilers were randomly divided into 4 groups, with 20 in each group, namely the negative control (group P), the E. coli Nissle 1917-treated group (group N), the S. Enteritidis-infected group (group S) and the E. coli Nissle 1917-treated and S. Enteritidis-infected group (group NS). From d 5 to 7, chicks in groups N and NS were orally gavaged once a day with E. coli Nissle 1917 and in groups P and S were administered the same volume of sterile PBS. At d 8, the chicks in groups S and NS were orally gavaged with S. Enteritidis and in groups P and N were administered the same volume of sterile PBS. Sampling was conducted 24 h after challenge. Results showed that gavage of E. coli Nissle 1917 reduced the spleen index, Salmonella loads, and inflammation (P < 0.05). It improved intestinal morphology and intestinal barrier function (P < 0.05). S. Enteritidis infection significantly reduced mRNA expression of angiotensin-converting enzyme 2 (ACE2) and solute carrier family 6-member 19 (SLC6A19) in the cecum and the content of Gly, Ser, Gln, and Trp in the serum (P < 0.05). Pretreatment with E. coli Nissle 1917 yielded mRNA expression of ACE2 and SLC6A19 in the cecum and levels of Gly, Ser, Gln, and Trp in the serum similar to that of uninfected chicks (P < 0.05). Additionally, E. coli Nissle 1917 altered cecum microbiota composition and enriched the abundance of E. coli, Lactobacillales, and Lachnospiraceae. These findings reveal that the probiotic E. coli Nissle 1917 reduced S. Enteritidis infection and shows enormous potential as an alternative to antibiotics.

Supplemental dietary genistein improves the laying performance and antioxidant capacity of Hy-Line brown hens during the late laying period.

The present study evaluated the effects of 3 supplemental levels of dietary genistein ingested during the late laying period (66-73 wk) of laying hens. A total of 384 Hy-Line brown hens (66 wk old) were randomly divided into 4 groups (6 replicates of 16 hens in each group), the basal diet group (CON), and groups for the basal diet supplemented with 80, 120, and 400 mg/kg of genistein, G1, G2, and G3, respectively. The results of the present study showed an increased laying rate in groups G2 and G3 (linear, P < 0.01), and decreased feed-egg ratios (linear, P < 0.05) and broken egg rate (P < 0.01) in all genistein-treated groups compared with the CON group. Moreover, the G2 group showed an increase in eggshell strength and ratio (linear, P < 0.05), whereas all genistein-treated groups saw a decrease in the L* value (linear, P < 0.01) and an increase in the a* value (linear, P < 0.05) compared with the CON group. Additionally, all genistein-treated groups had an increase in the total antioxidant capacity of plasma (linear, P < 0.05), along with reduced plasma, ovarian, and yolk malondialdehyde levels (linear, P < 0.05), compared with the CON group. The G2 group had an increase in both the superoxide dismutase activity of plasma (P < 0.01) and the total antioxidant capacity of the ovaries (linear, P < 0.05), compared with the CON group. The G3 group had an increase in both the glutathione peroxidase concentration of plasma (linear, P < 0.05) and the total antioxidant capacity of the ovaries (linear, P < 0.01), compared with the CON group. The transcript levels of nuclear factor erythroid 2-related factor 2, superoxide dismutase 1, and catalase were increased in all of the genistein-treated groups (P < 0.05) compared with the CON group, whereas heme oxygenase 1 and glutamate-cysteine ligase modifier subunit were increased only in the G2 group (P < 0.05). In conclusion, supplementation with 120 mg/kg dietary genistein had the best effect on improving the laying rate, eggshell quality, and antioxidant capacity in Hy-Line brown hens during the late laying period.

Whole genome analyses reveal novel genes associated with chicken adaptation to tropical and frigid environments.

INTRODUCTION: Investigating the genetic footprints of historical temperature selection can get insights to the local adaptation and feasible influences of climate change on long-term population dynamics. OBJECT: Chicken is a significative species to study genetic adaptation on account of its similar domestication track related to human activity with the most diversified varieties. Yet, few studies have demonstrated the genetic signatures of its adaptation to naturally tropical and frigid environments. METHOD: Here, we generated whole genome resequencing of 119 domesticated chickens in China including the following breeds which are in order of breeding environmental temperature from more tropical to more frigid: Wenchang chicken (WCC), green-shell chicken (GSC), Tibetan chicken (TBC), and Lindian chicken (LDC). RESULTS: Our results showed WCC branched off earlier than LDC with an evident genetic admixture between WCC and LDC, suggesting their closer genetic relationship. Further comparative genomic analyses solute carrier family 33 member 1 (SLC33A1) and thyroid stimulating hormone receptor (TSHR) genes exhibited stronger signatures for positive selection in the genome of the more tropical WCC. Furthermore, genotype data from about 3,000 African local ecotypes confirmed that allele frequencies of single nucleotide polymorphisms (SNPs) in these 2 genes appeared strongly associated with tropical environment adaptation. In addition, the NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4) gene exhibited a strong signature for positive selection in the LDC genome, and SNPs with marked allele frequency differences indicated a significant relationship with frigid environment adaptation. CONCLUSION: Our findings partially clarify how selection footprints from environmental temperature stress can lead to advantageous genomic adaptions to tropical and frigid environments in poultry and provide a valuable resource for selective breeding of chickens.

Three-Dimensional Organization of Chicken Genome Provides Insights into Genetic Adaptation to Extreme Environments.

The high-throughput chromosome conformation capture (Hi-C) technique is widely used to study the functional roles of the three-dimensional (3D) architecture of genomes. However, the knowledge of the 3D genome structure and its dynamics during extreme environmental adaptations remains poor. Here, we characterized 3D genome architectures using the Hi-C technique for chicken liver cells. Upon comparing Lindian chicken (LDC) liver cells with Wenchang chicken (WCC) liver cells, we discovered that environmental adaptation contributed to the switching of A/B compartments, the reorganization of topologically associated domains (TADs), and TAD boundaries in both liver cells. In addition, the analysis of the switching of A/B compartments revealed that the switched compartmental genes (SCGs) were strongly associated with extreme environment adaption-related pathways, including tight junction, notch signaling pathway, vascular smooth muscle contraction, and the RIG-I-like receptor signaling pathway. The findings of this study advanced our understanding of the evolutionary role of chicken 3D genome architecture and its significance in genome activity and transcriptional regulation.

Supplementing the early diet of broilers with soy protein concentrate can improve intestinal development and enhance short-chain fatty acid-producing microbes and short-chain fatty acids, especially butyric acid.

BACKGROUND: Research on nutrition in early-life commonly focuses on the maturation of the intestine because the intestinal system is crucial for ensuring continued growth. To explore the importance of early nutrition regulation in animals, soy protein concentrate (SPC) was added to the early diet of broilers to investigate its effects on amino acid digestibility, intestinal development, especially intestinal microorganisms, and broiler metabolites. A total of 192 one-day-old Arbor Acres (AA) male broilers were randomly assigned to two experimental treatments with 8 replicates of 12 birds. The control group was fed a basal diet (control), and the treatment group was fed a basal diet supplemented with 12% SPC (SPC12) during the first 10 d (starter phase). From d 11 to 21 (grower phase) and d 22 to 42 (finisher phase), a basal diet was fed to both treatment groups. RESULTS: SPC reduced the pH value and acid-binding capacity of the starter diet (P < 0.05, d 10); SPC in the early diet enhanced the gizzard weight (P < 0.05, d 10 and d 42) and the ileum weight (P < 0.05, d 10) and decreased the weight and length of the jejunum (P < 0.05, d 10) and the relative length of the duodenum and jejunum (P < 0.05, d 10). At the same time, SPC enhanced villus height (P < 0.05, d 10) and muscle thickness in the jejunum and ileum (P < 0.05, d 10) and increased the number of goblet cells in the duodenum (P < 0.05, d 10). Meanwhile, SPC increased the Chao1 index and the ACE index (P < 0.05, d 10) and altered the composition of caecal microflora at d 10. SPC also increased the relative abundance of Alistipes, Anaerotruncus, Erysipelatoclostridium, Intestinimonas and Flavonifractor bacteria (P < 0.05, d 10). At the same time, the concentrations of caecal butyric acid and total short-chain fatty acids (SCFAs) were also increased in the SPC12 group (P < 0.05, d 10). CONCLUSIONS: In summary, the results showed that supplementing the starter diet of broilers with SPC has a significant effect on the early development of the intestine and the microflora.

Heat stress-induced intestinal barrier damage and dimethylglycine alleviates via improving the metabolism function of microbiota gut brain axis.

Heat stress, a widely occurred in subtropical climate regions, causes ecosystem destruction, and intestine injury in humans and animals. As an important compound in the metabolic pathway of choline, dimethylglycine (DMG) shows anti-inflammatory effects. This study examines the beneficial effects of dietary DMG against heat stress-induced intestine injury and further explores the underlying molecular mechanisms using a broiler model. Here, we showed that DMG supplements exhibited positive effects to growth performance, as evidenced by the significantly increased body weight and feed conversion rate. These therapeutic effects attributed to repaired gut barrier integrity, increased content of anti-inflammatory cytokines IL-10, decreased content of pro-inflammatory cytokines IL-6, and down-regulated gene expression of the NF-κB signaling pathway. DMG treatment led to the reshaping of the gut microbiota composition, mainly increasing the short-chain fatty acid (SCFAs) strains such as Faecalibacterium, and Marvinbryantia. DMG treatment also increased two main members of SCFAs, including acetate acid and isobutyrate. Particularly, distinct effects were found which mediated the tryptophan metabolism in intestines such as increased tryptophan and 5-HT, which further alleviate the occurrence of intestinal barrier damage caused by heat stress. Additionally, DMG treatment promoted neuroendocrine function and stimulated the hypothalamic neurotransmitter metabolism by activating tryptophan metabolism in the hypothalamus. Overall, DMG supplementation effectively reduced the occurrence of intestinal inflammation induced by heat stress through modulating cecal microbial communities and improving the metabolism function of microbiota gut brain axis. Our findings revealed a novel mechanism by which gut microbiota could improve host health.

Low protein with high amino acid diets improves the growth performance of yellow feather broilers by improving intestinal health under cyclic heat stress.

This study investigated the effects of a low-protein diet supplemented with high lysine, methionine, and threonine levels on production performance, antioxidant capacity, intestinal morphology, duodenum gene expression and intestinal microorganisms in yellow feather broilers under cyclic heat stress. A total of 162 yellow feather broilers that were 42 d of age were selected and randomly divided into three groups: the control group (CONT, CP 16%), heat stress group (HS, CP 16%), and heat stress with low protein and high amino acid group (HS_LP, CP 14.5%). Following 14 d heating stress period, the HS_LP group showed no significant effect on production performance compared with the HS group. After a 28 d feeding trial, compared with the HS group, the HS_LP group significantly reduced feed: gain at 15-28 d (P < 0.05), had a tendency to reduce feed: gain at 1-28 d (P = 0.056). Compared with the HS group, the serum catalase enzyme activity tended to be higher (P = 0.067), and liver glutathione peroxidase enzyme activity was significantly decreased (P < 0.05) in the HS_LP group. Other antioxidant capacity indexes were not significantly different between the two groups (P > 0.05). Duodenum (P < 0.05) and ileum (P < 0.05) villus height were significantly increased, duodenum villus height: crypt depth ratio (P < 0.05) and jejunum crypt depth (P < 0.05) were significantly decreased, and jejunum villus height was significantly reduced (P < 0.05) in broilers fed the HS_LP diet. Compared with the HS group, the mRNA level of Claudin-1 was significantly increased (P < 0.05), and had a tendency to increase Occludin (P = 0.060) in the HS_LP group. In addition, the HS_LP group significantly increased Nitrosomonas abundance (P < 0.05) and had a tendency to reduce unidentified_Mollicutes abundance (P = 0.083) at the genus level compared with the HS group. This information is useful to formulate diets that correct the decrease in amino acid consumption associated with the reduced voluntary feed intake of broilers under heat stress.

Effects of dietary dimethylglycine supplementation on laying performance, egg quality, and tissue index of hens during late laying period.

In this study, the effects of 5 graded dietary levels (0.025, 0.05, 0.075, 0.1, and 0.125%) of dimethylglycine (DMG) were studied in laying hens during the late laying period (71-78 wk). Graded doses of DMG from 0.025 to 0.125% in the diet produced quadratic positive (P < 0.05) responses in the laying rate, egg-feed ratio, yolk color, grade follicular weight, and the number of large white follicles and linear positive (P < 0.05) responses in average egg weight, and the number of large white follicles. With 0.1% DMG, the laying rate and egg-feed ratio improved (P < 0.05), and the abdominal fat percentage decreased. Considering the laying performance under the conditions used in this study, the best-fit model for the DMG requirements of laying hens was estimated to range from 0.049 to 0.065% DMG during the late laying period based on a regression analysis. The addition of DMG did not affect the total cholesterol (TCH) and triglyceride (TG) contents in the plasma of laying hens; however, it significantly reduced the abdominal fat rate. DMG may change the course of lipid deposition in laying hens during the late laying period. In conclusion, supplementation with DMG can improve the laying rate and follicles development of laying hens.

Evaluation of a Lecithin Supplementation on Growth Performance, Meat Quality, Lipid Metabolism, and Cecum Microbiota of Broilers.

The present study was conducted to evaluate the effects of lecithin on the performance, meat quality, lipid metabolism, and cecum microbiota of broilers. One hundred and ninety-two one-day-old AA broilers with similar body weights (38 ± 1.0 g) were randomly assigned to two groups with six replicates of sixteen birds each and were supplemented with 0 and 1 g/kg of lecithin for forty-two days. Performance and clinical observations were measured and recorded throughout the study. Relative organ weight, meat quality, lipid-related biochemical parameters and enzyme activities were also measured. Compared with broilers in the control group, broilers in the lecithin treatment group showed a significant increase in L* value and tenderness (p < 0.05). Meanwhile, the abdominal adipose index of broilers was markedly decreased in lecithin treatment after 42 days (p < 0.05). In the lipid metabolism, broilers in the lecithin treatment group showed a significant increase in hepatic lipase and general esterase values at 21 days compared with the control group (p < 0.05). Lower Firmicutes and higher Bacteroidetes levels in phylum levels were observed in the lecithin treatment group after 21 and 42 days. The distribution of lactobacillus, clostridia, and rikenella in genus levels were higher in the lecithin treatment group after 21 and 42 days. No statistically significant changes were observed in performance, relative organ weight, or other serum parameters (p > 0.05). These results indicate that supplementation with lecithin significantly influence the lipid metabolism in broilers at 21 and 42 days, which resulted in the positive effect on the meat color, tenderness, and abdominal adipose in broilers.

Infection Heterogeneity and Microbiota Differences in Chicks Infected by Salmonella enteritidis.

This study was conducted to compare the infection heterogeneity and cecal microbiota in chicks infected by S. enteritidis. Forty-eight 8-d-old female Arbor Acres chicks were challenged with S. enteritidis and euthanized 24 h later. The eight chicks with the highest Salmonella tissue loads were assigned to group S (S. enteritidis-susceptible), and the eight chicks with the lowest Salmonella tissue loads were assigned to group R (S. enteritidis-resistant). Chicks in group S showed a higher liver index (p < 0.05), obvious liver lesions, and an decreasing trend for the villus height-to-crypt depth ratio (p < 0.10), compared with those in group R. Gene expression of occludin, MUC2, and IL10 was higher, whereas that of iNOS and IL6 was lower (p < 0.05), in chicks of group R relative to those in group S. Separation of the cecal microbial community structure has been found between the two groups. The S. enteritidis-susceptible chicks showed higher abundance of pathogenic bacteria (Fusobacterium and Helicobacter) in their cecal, while Desulfovibrio_piger was enriched in the cecal of S. enteritidis-resistant chicks. In summary, chicks showed heterogeneous responses to S. enteritidis infection. Enhanced intestinal barrier function and cecal microbiota structure, especially a higher abundance of Desulfovibrio_piger, may help chicks resist S. enteritidis invasion.

Comparative transcriptomic analysis of ovaries from high and low egg-laying Lingyun black-bone chickens.

Egg-laying rate is mainly determined by ovarian function and regulated by the hypothalamic-pituitary-gonadal axis; however, the mechanism by which the ovary regulates the egg-laying rate is still poorly understood. The purpose of this study was to compare the differences in the transcriptomes of the ovary of Lingyun black-bone chickens with relatively high and low egg-laying rates and screen candidate genes related to the egg-laying rate. RNA-sequencing (RNA-Seq) was conducted to explore the chicken transcriptome from the ovarian tissue of six Lingyun black-bone chickens with high (group G, n = 3) and low (group D, n = 3) egg-laying rates. The results showed that 235 differentially expressed genes (DEGs) were identified between the chickens with high and low egg-laying rates; among them, 209 DEGs were up-regulated and 26 DEGs were down-regulated. Gene Ontology analysis showed that the up-regulated 209 DEGs were enriched in 50 GO terms and the down-regulated 26 DEGs were enriched in 40 GO terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that up-regulated DEGs were significantly enriched in 25 pathways and down-regulated DEGs were significantly enriched in three pathways. Among the pathways, we found the longevity regulating pathway-multiple species pathway, Estrogen signalling pathway and PPAR signalling pathway may have an essential function in regulating the egg-laying rate. The results highlighted DEGs in the ovarian tissues of relatively high and low laying Lingyun black-bone chicken and identified essential candidate genes related to the egg-laying rate, thereby providing a theoretical basis for improving the egg-laying rate of Lingyun black-bone chicken.

Comparative Metagenomic Analysis of Chicken Gut Microbial Community, Function, and Resistome to Evaluate Noninvasive and Cecal Sampling Resources.

When conducting metagenomic analysis on gut microbiomes, there is no general consensus concerning the mode of sampling: non-contact (feces), noninvasive (rectal swabs), or cecal. This study aimed to determine the feasibility and comparative merits and disadvantages of using fecal samples or rectal swabs as a proxy for the cecal microbiome. Using broiler as a model, gut microbiomes were obtained from cecal, cloacal, and fecal samples and were characterized according to an analysis of the microbial community, function, and resistome. Cecal samples had higher microbial diversity than feces, while the cecum and cloaca exhibited higher levels of microbial community structure similarity compared with fecal samples. Cecal microbiota possessed higher levels of DNA replicative viability than feces, while fecal microbiota were correlated with increased metabolic activity. When feces were excreted, the abundance of antibiotic resistance genes like tet and ErmG decreased, but some antibiotic genes became more prevalent, such as fexA, tetL, and vatE. Interestingly, Lactobacillus was a dominant bacterial genus in feces that led to differences in microbial community structure, metabolism, and resistome. In conclusion, fecal microbiota have limited potential as a proxy in chicken gut microbial community studies. Thus, feces should be used with caution for characterizing gut microbiomes by metagenomic analysis.

Dietary supplementation with daidzein and Chinese herbs, independently and combined, improves laying performance, egg quality and plasma hormone levels of post-peak laying hens.

This experiment examined the separate and combined effects of daidzein (Da) and Chinese herbs (CH) on laying performance and egg quality of post-peak laying hens. Additionally, we explored potential mechanisms of action for these 2 additives by examining plasma hormone levels. After 4 wk of acclimation to caging, 60-week-old Hyline Brown hens (360) were selected and randomly divided into 4 groups with 6 replicates and 15 chickens per replicate. The following 4 dietary groups were utilized: 1) control group (basal diet); 2) Da group (basal diet + 0.03 kg/t DA); 3) CH group (basal diet +0.6 kg/t CH); 4) Da + CH group (basal diet + 0.03 kg/t Da + 0.6 kg/t CH). Data were analyzed in a completely randomized design with a 2×2 factorial arrangement of treatments. Egg production and FCR treatment averages were analyzed in the following 3 phases: wk 1-4, 5-8, and 1-8 of treatment administration. Results revealed that Da increased egg production but decreased FCR (P < 0.05) for wk 1-8 and especially during wk 5-8 (P < 0.05). CH decreased FCR in wk 1-4 and 5-8 (P < 0.05), but increased egg production only during wk 5-8 (P < 0.05). Da increased Haugh units (P < 0.05) on wk 4 and 8; CH increased Haugh units (P < 0.05) but decreased yolk ratio (P < 0.05) on wk 4 and 8. Da increased the plasma levels of T3, PROG, FSH, LH and E2 (P < 0.05); CH increased the plasma level of T3 (P < 0.05). Additionally, Da x CH interactions existed for albumen height, Haugh units, albumen ratio and the level of T3 on wk 8 (P < 0.05), indicating that the combination of Da and CH was more effective than administration of either of these dietary components independently. In conclusion, Da and CH, both independently and in combination, increase laying performance, egg quality and plasma hormones levels in post-peak laying hens. Therefore, these treatments may be able to provide prolonged economic benefits to aged laying hens.

Dietary supplementation with Bacillus subtilis promotes growth performance of broilers by altering the dominant microbial community.

The purpose of this study was to investigate the effects of Bacillus subtilis on growth performance, intestinal morphology, and cecal microbial composition of broilers. A total of 270 healthy one-day-old Arbor Acres male broiler chicks were randomly divided into 3 dietary treatment groups, with 6 replicates per group and 15 chickens per replicate. The dietary treatment groups were as follows: 1) basal diet, negative control group; 2) basal diet +250 g/t of zinc bacitracin, positive control group; and 3) basal diet +750 g/t of B. subtilis, B. subtilis group. Results of this experiment showed that compared with the negative control group, body weight at 42 d, average daily gain and European Production Efficiency Factor over the 42 d phase in the B. subtilis group and positive control group were significantly increased (P < 0.05); feed conversion rates in the B. subtilis group and positive control group were significantly decreased (P < 0.05); and average daily feed intake and mortality were not significantly different (P > 0.05). The villus height to crypt depth ratio in the ileum of the B. subtilis group was significantly higher (P < 0.05) than that of the negative control group. The results of cecal microflora at genus level were as follows. As compared with the negative control group, the abundance of Blautia, Faecalibacterium, Flavonifractor, and Hydrogenoanaerobacterium of the B. subtilis group and positive control group was significantly higher (P < 0.05), whereas the abundance of Odoribacter was significantly lower (P < 0.05). Moreover, abundance of the genera Romboutsia in the B. subtilis group was higher (P < 0.05) than that in the positive control group. The abundance of Flavonifractor, Erysipelatoclostridium, and Hydrogenoanaerobacterium were positively correlated with body weight and average daily gain by Spearman correlation analysis. In conclusion, dietary supplementation with B. subtilis improved growth performance of broilers which may be related to the increased abundance of Blautia, Faecalibacterium, Flavonifractor, Hydrogenoanaerobacterium, and Romboutsia, along with the decreased abundance of Odoribacter. In addition, the effect of B. subtilis was superior to zinc bacitracin in improving intestinal microbial composition of broilers. Therefore, B. subtilis may act as an effective antibiotic substitute in broilers.

Effects of Soy Protein Concentrate in Starter Phase Diet on Growth Performance, Blood Biochemical Indices, Carcass Traits, Immune Organ Indices and Meat Quality of Broilers.

Soybean meal (SBM) is high in antinutritional factors (ANFs), which is not conducive to the starter growth of broilers. The purpose of this study was to investigate the effects of soy protein concentrate (SPC) in starter diet on growth performance, carcass traits, meat quality, immune organ indices and blood biochemical indices of broilers. A total of 384 1-day-old Arbor Acres (AA) male broilers (46.05 ± 0.37 g) with similar body weight were randomly divided into 4 groups with 8 replicates in each group and 12 broilers in each replicate. The experiment was divided into three phases: in starter phase (1-10 d), birds were fed a corn-SBM-based basal mash diet (control) and the basal diet was supplemented with SPC at 4% (SPC4), 8% (SPC8), 12% (SPC12). In the grower phase (11-21 d) and the finisher phase (22-42 d), the birds in all four treatment groups were fed the same diets. The results showed that the body weight was significantly increased in the SPC8 and SPC12 groups of broilers at 10 d and 42 d (p < 0.05). The average daily gain was significantly increased in the SPC12 group of broilers at 1-10 d and 1-42 d (p < 0.05). The average daily feed intake was significantly increased in the SPC8 and SPC12 groups of broilers at 1-10 d (p < 0.05). The feed conversion rates at 1-42 d (p = 0.055) tended to decline in the SPC12 group. The carcass yield and the thymus indices were significantly increased in the SPC12 group of broilers at 42 d (p < 0.05). Alanine aminotransferase (ALT)/ aspartate aminotransferase (AST) tended to decline in SPC12 group at 10 d (p = 0.055) and total protein (TP) tended to increase in the SPC12 group at 42 d (p = 0.080). The contents of total cholesterol (T-CHO) and high-density lipoprotein (HDL) were significantly elevated in the SPC12 group of broilers at 42 d (p < 0.05). In conclusion, dietary inclusion of 12% SPC as a starter diet can be recommended due to the positive effects on broilers.

Correction to 'Cytotoxicity studies of Fe3O4 nanoparticles in chicken macrophage cells'.

[This corrects the article DOI: 10.1098/rsos.191561.].