State Key Laboratory of Animal Nutrition

Abstract Comparative population genomics offers an opportunity to discover the signatures of artificial selection during animal domestication, however, their function cannot be directly revealed. We discover the selection signatures using genome-wide comparisons among 40 mallards, 36 indigenous-breed ducks, and 30 Pekin ducks. Then, the phenotypes are fine-mapped based on resequencing of 1026 ducks from an F 2 segregating population generated by wild × domestic crosses. Interestingly, the two key economic traits of Pekin duck are associated with two selective sweeps with fixed mutations. A novel intronic insertion most possibly leads to a splicing change in MITF accounted for white duck down feathers. And a putative long-distance regulatory mutation causes continuous expression of the IGF2BP1 gene after birth which increases body size by 15% and feed efficiency by 6%. This study provides new insights into genotype–phenotype associations in animal research and constitutes a promising resource on economically important genes in fowl.

The effects of chronic heat stress on growth, proportion of carcass and fat deposition, and meat quality were investigated in 2 genetic types of chickens. One hundred and eight 5-wk-old male chickens from a commercially fast-growing strain (Arbor Acres, AA) and a locally slow-growing species (Beijing You chicken, BJY) were kept in the following conditions: constant optimal ambient temperature at 21 degrees C and ad libitum feeding (21AL), constant high ambient temperature at 34 degrees C and ad libitum feeding (34AL), and constant optimal ambient temperature 21 degrees C and pair-fed to the 34AL chickens (21PF). The results showed that feed intakes were decreased by heat exposure in both type of chickens at 8 wk of age (P<0.001). At 34 degrees C, AA broilers exhibited greatly decreased weight gain (22.38 vs. 61.45 g/d for 21AL) and lower breast proportion compared with 21AL, while the relevant indices of BJY chickens were not affected in hot condition. Abdominal fat deposition of BJY chickens was enhanced by heat exposure (P<0.05). Fat deposition of AA broilers was decreased in heat-exposed and pair-fed chickens. Abdominal and intermuscular fat deposition in 34AL birds, however, were enhanced compared with 21PF birds (P<0.01). The L* values, drip loss, initial pH, and shear force of breast meat in BJY chickens were not affected by treatments. In AA birds, chronic heat stress increased L* values and drip loss compared with 21AL, but pH and shear force were not affected by treatments. The results from this study indicated that the impact of heat stress was breed dependent and that BJY chickens showed higher resistance to high ambient temperature, which could be related to their increased feed efficiency and deposition of abdominal fat under heat exposure.

Local thyroid hormone catabolism within the mediobasal hypothalamus (MBH) by thyroid hormone-activating (DIO2) and -inactivating (DIO3) enzymes regulates seasonal reproduction in birds and mammals. Recent functional genomics analysis in birds has shown that long days induce thyroid-stimulating hormone production in the pars tuberalis (PT) of the pituitary gland, which triggers DIO2 expression in the ependymal cells (EC) of the MBH. In mammals, nocturnal melatonin secretion provides an endocrine signal of the photoperiod to the PT that contains melatonin receptors in high density, but the interface between the melatonin signal perceived in the PT and the thyroid hormone levels in the MBH remains unclear. Here we provide evidence in mice that TSH participates in this photoperiodic signal transduction. Although most mouse strains are considered to be nonseasonal, a robust photoperiodic response comprising induced expression of TSHB (TSH beta subunit), CGA (TSH alpha subunit), and DIO2, and reduced expression of DIO3, was observed in melatonin-proficient CBA/N mice. These responses could not be elicited in melatonin-deficient C57BL/6J, but treatment of C57BL/6J mice with exogenous melatonin elicited similar effects on the expression of the above-mentioned genes as observed in CBA/N after transfer to short-day conditions. The EC was found to express TSH receptor (TSHR), and ICV injection of TSH induced DIO2 expression. Finally, we show that melatonin administration did not affect the expression of TSHB, DIO2, and DIO3 in TSHR-null mice. Taken together, our findings suggest that melatonin-dependent regulation of thyroid hormone levels in the MBH appears to involve TSH in mammals.

Ferroptosis, an autophagy-dependent cell death, is characterized by lipid peroxidation and iron accumulation, closely associated with pathogenesis of gestational diabetes mellitus (GDM). Sirtuin 3 (SIRT3) has positive regulation on phosphorylation of activated protein kinase (AMPK), related to maintenance of cellular redox homeostasis. However, whether SIRT3 can confer autophagy by activating the AMPK-mTOR pathway and consequently promote induction of ferroptosis is unknown. We used human trophoblastic cell line HTR8/SVneo and porcine trophoblastic cell line pTr2 to deterimine the mechanism of SIRT3 on autophagy and ferroptosis. The expression of SIRT3 protein was significantly elevated in trophoblastic cells exposed to high concentrations of glucose and ferroptosis-inducing compounds. Increased SIRT3 expression contributed to classical ferroptotic events and autophagy activation, whereas SIRT3 silencing led to resistance against both ferroptosis and autophagy. In addition, autophagy inhibition impaired SIRT3-enhanced ferroptosis. On the contrary, autophagy induction had a synergistic effect with SIRT3. Based on mechanistic investigations, SIRT3 depletion inhibited activation of the AMPK-mTOR pathway and enhanced glutathione peroxidase 4 (GPX4) level, thereby suppressing autophagy and ferroptosis. Furthermore, depletion of AMPK blocked induction of ferroptosis in trophoblasts. We concluded that upregulated SIRT3-enhanced autophagy activation by promoting AMPK-mTOR pathway and decreasing GPX4 level to induce ferroptosis in trophoblastic cells. SIRT3 deficiency was resistant to high glucose- and erastin-induced autophagy-dependent ferroptosis and is, therefore, a potential therapeutic approach for treating GDM.

A better understanding of global ruminal microbiota and metabolites under extensive feeding conditions is a prerequisite for optimizing rumen function and improving ruminant feed efficiency. Furthermore, the gap between the information on the ruminal microbiota and metabolites needs to be bridged. The aim of this study was to investigate the effects of a wide range of forage to concentrate ratios (F:C) on changes and interactions of ruminal microbiota and metabolites. Four diets with different F:C (80:20, 60:40, 40:60, and 20:80) were limit-fed to 24 Holstein heifers, and Illumina MiSeq sequencing and gas chromatography time-of-flight/mass spectrometry were used to investigate the profile changes of the ruminal microbes and metabolites, and the interaction between them. The predominant bacterial phyla in the rumen were Bacteroidetes (57.2 ± 2.6%) and Firmicutes (26.8 ± 1.6%), and the predominant anaerobic fungi were Neocallimastigomycota (64.3 ± 3.8%) and Ascomycota (22.6 ± 2.4%). In total, 44, 9, 25, and 2 genera, respectively, were identified as the core rumen bacteria, ciliate protozoa, anaerobic fungi, and archaea communities across all samples. An increased concentrate level linearly decreased the relative abundance of cellulolytic bacteria and ciliates, namely Fibrobacter, Succinimonas, Polyplastron, and Ostracodinium (q < 0.05), and linearly increased the relative abundance of Entodinium (q = 0.04), which is a non-fibrous carbohydrate degrader. Dietary F:C had no effect on the communities of anaerobic fungi and archaea. Rumen metabolomics analysis revealed that ruminal amino acids, lipids, organic acids, and carbohydrates were altered significantly by altering the dietary F:C. With increasing dietary concentrate levels, the proportions of propionate and butyrate linearly increased in the rumen (P ≤ 0.01). Correlation analysis revealed that there was some utilization relationship or productive association between candidate metabolites and affected microbe groups. This study provides a better understanding of ruminal microbiota and metabolites under a wide range of dietary F:C, which could further reveal integrative information of rumen function and lead to an improvement in ruminant production.

This study investigated the protective effect of β-1,3/1,6-glucan on gut morphology, intestinal epithelial tight junctions, and bacterial translocation of broiler chickens challenged with Salmonella enterica serovar Typhimurium. Ninety Salmonella-free Arbor Acre male broiler chickens were randomly divided into 3 groups: negative control group (NC), Salmonella Typhimurium-infected positive group (PC), and the Salmonella Typhimurium-infected group with dietary 100 mg/kg of β-1,3/1,6-glucan supplementation (T) to determine the effect of β-1,3/1,6-glucan on intestinal barrier function. Salmonella Typhimurium challenge alone significantly decreased villus height (P < 0.001), villus height/crypt depth ratio (P < 0.05), and the number of goblet cells (P < 0.001) in the jejunum at 14 d postinfection (dpi), but significantly increased the number of intestinal secretory IgA (sIgA)-expressing cells at 14 dpi (P < 0.01) and total sIgA levels in the jejunum at 7 (P < 0.05) and 14 dpi (P < 0.01) compared with the unchallenged birds (NC). Dietary β-1,3/1,6-glucan supplementation not only significantly increased villus height, villus height/crypt depth ratio, and the number of goblet cells (P < 0.01), but also increased the number of sIgA-expressing cells (P < 0.05) and sIgA content in the jejunum at 14 dpi (P < 0.01) in birds challenged with Salmonella Typhimurium in comparison with Salmonella Typhimurium challenge alone. β-1,3/1,6-Glucan addition had significant inhibitory effects (P < 0.05) on cecal Salmonella colonization levels and liver Salmonella invasion of the Salmonella Typhimurium-infected birds compared with the PC group. Intestinal tight junction proteins claudin-1, claudin-4, and occludin mRNA expression in the jejunum at 14 dpi was significantly decreased by Salmonella Typhimurium challenge alone (P < 0.01) compared with that of the NC group, whereas β-1,3/1,6-glucan supplementation significantly increased claudin-1 and occludin mRNA expression (P < 0.01) at 14 dpi in the jejunum of the Salmonella Typhimurium-infected birds in comparison with the PC group. Our results indicate that dietary β-1,3/1,6-glucan can alleviate intestinal mucosal barrier impairment in broiler chickens challenged with Salmonella Typhimurium.

Abstract The current review is designed with aims to highlight the impact of heat stress (HS) on calves and heifers and to suggest methods for HS alleviation. HS occurs in animals when heat gain from environment and metabolism surpasses heat loss by radiation, convection, evaporation and conduction. Although calves and heifers are comparatively heat resistant due to less production of metabolic heat and more heat dissipation efficiency, they still suffer from HS to some degree. Dry matter intake and growth performance of calves and heifers are reduced during HS because of redistributing energy to heat regulation through a series of physiological and metabolic responses, such as elevated blood insulin and protein catabolism. Enhanced respiration rate and panting during HS accelerate the loss of CO 2 , resulting in altered blood acid-base chemistry and respiratory alkalosis. HS-induced alteration in rumen motility and microbiota affects the feed digestibility and rumen fermentation. Decreased luteinizing hormone, estradiol and gonadotrophins due to HS disturb the normal estrus cyclicity, depress follicular development, hence the drop in conception rate. Prenatal HS not only suppresses the embryonic development by the impaired placenta, which results in hypoxia and malnutrition, but also retards the growth, immunity and future milk production of newborn calves. Based on the above challenges, we attempted to describe the possible impacts of HS on growth, health, digestibility and reproduction of calves and heifers. Likewise, we also proposed three primary strategies for ameliorating HS consequences. Genetic development and reproductive measures, such as gene selection and embryo transfers, are more likely long-term approaches to enhance heat tolerance. While physical modification of the environment, such as shades and sprinkle systems, is the most common and easily implemented measure to alleviate HS. Additionally, nutritional management is another key approach which could help calves and heifers maintain homeostasis and prevent nutrient deficiencies because of HS.

BACKGROUND: Intramuscular fat (IMF) is one of the important factors influencing meat quality, however, for chickens, the molecular regulatory mechanisms underlying this trait have not yet been determined. In this study, a systematic identification of candidate genes and new pathways related to IMF deposition in chicken breast tissue has been made using gene expression profiles of two distinct breeds: Beijing-you (BJY), a slow-growing Chinese breed possessing high meat quality and Arbor Acres (AA), a commercial fast-growing broiler line. RESULTS: Agilent cDNA microarray analyses were conducted to determine gene expression profiles of breast muscle sampled at different developmental stages of BJY and AA chickens. Relative to d 1 when there is no detectable IMF, breast muscle at d 21, d 42, d 90 and d 120 (only for BJY) contained 1310 differentially expressed genes (DEGs) in BJY and 1080 DEGs in AA. Of these, 34-70 DEGs related to lipid metabolism or muscle development processes were examined further in each breed based on Gene Ontology (GO) analysis. The expression of several DEGs was correlated, positively or negatively, with the changing patterns of lipid content or breast weight across the ages sampled, indicating that those genes may play key roles in these developmental processes. In addition, based on KEGG pathway analysis of DEGs in both BJY and AA chickens, it was found that in addition to pathways affecting lipid metabolism (pathways for MAPK & PPAR signaling), cell junction-related pathways (tight junction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton), which play a prominent role in maintaining the integrity of tissues, could contribute to the IMF deposition. CONCLUSION: The results of this study identified potential candidate genes associated with chicken IMF deposition and imply that IMF deposition in chicken breast muscle is regulated and mediated not only by genes and pathways related to lipid metabolism and muscle development, but also by others involved in cell junctions. These findings establish the groundwork and provide new clues for deciphering the molecular mechanisms underlying IMF deposition in poultry. Further studies at the translational and posttranslational level are now required to validate the genes and pathways identified here.

When a defect occurs in the in vitro development of a pronuclear embryo, the interruption of the subsequent implantation limits the success of assisted conception. This common problem remains to be solved. In this study, we observed that melatonin at its physiological concentration (10(-7) m) significantly promoted the in vitro development of murine pronuclear embryos. This was indicated by the increased blastocyst rate, hatching blastocyst rate, and blastocyst cell number with melatonin treatment. In addition, when these blastocysts were implanted into female recipient mice, the pregnancy rates (95.0% versus control 67.8%), litter sizes (4.1 pups/litter versus control 2.7 pups/litter), and postnatal survival rates of offspring (96.84% versus control 81.24%) were significantly improved compared with their non-melatonin-treated counterparts. Mechanistic studies revealed that melatonin treatment upregulates gene expression of the antioxidant enzyme, superoxide dismutase (SOD), and the anti-apoptotic factor bcl-2 while downregulating the expression of pro-apoptotic genes p53 and caspase-3. Due to these changes, melatonin treatment reduces ROS production and cellular apoptosis during in vitro embryo development and improves the quality of blastocysts. The implantation of blastocysts with higher quality leads to more healthy offspring and increased pup survival.

Body composition and meat quality traits are important economic traits of chickens. The development of high-throughput genotyping platforms and relevant statistical methods have enabled genome-wide association studies in chickens. In order to identify molecular markers and candidate genes associated with body composition and meat quality traits, genome-wide association studies were conducted using the Illumina 60 K SNP Beadchip to genotype 724 Beijing-You chickens. For each bird, a total of 16 traits were measured, including carcass weight (CW), eviscerated weight (EW), dressing percentage, breast muscle weight (BrW) and percentage (BrP), thigh muscle weight and percentage, abdominal fat weight and percentage, dry matter and intramuscular fat contents of breast and thigh muscle, ultimate pH, and shear force of the pectoralis major muscle at 100 d of age. The SNPs that were significantly associated with the phenotypic traits were identified using both simple (GLM) and compressed mixed linear (MLM) models. For nine of ten body composition traits studied, SNPs showing genome wide significance (P<2.59E-6) have been identified. A consistent region on chicken (Gallus gallus) chromosome 4 (GGA4), including seven significant SNPs and four candidate genes (LCORL, LAP3, LDB2, TAPT1), were found to be associated with CW and EW. Another 0.65 Mb region on GGA3 for BrW and BrP was identified. After measuring the mRNA content in beast muscle for five genes located in this region, the changes in GJA1 expression were found to be consistent with that of breast muscle weight across development. It is highly possible that GJA1 is a functional gene for breast muscle development in chickens. For meat quality traits, several SNPs reaching suggestive association were identified and possible candidate genes with their functions were discussed.

Soil lead (Pb) pollution is wide spread in China. The Chinese government is taking ambitious actions to tackle the soil pollution issue, with the latest soil quality standards and the Soil Pollution Prevention and Remediation Law enacted in 2018. This study assesses the spatio-temporal distribution, pollution levels, major sources and health risks of Pb in surface soils in China in the past three decades (1990–2017). Traffic emissions (mainly leaded gasoline), mining, smelting, and e-waste recycling were main contributors to soil Pb pollution and pose a risk to food security and human health. The weighted arithmetic mean of Pb concentrations was 35.9 ± 0.21 mg/kg. Southern China suffered from severer soil Pb pollution with hotspots of the Pearl River Delta, Yangtze River Delta, Shaanxi and Hunan. The average soil Pb concentration increased marginally during 1990–2001 due to increased industrial and transportation activities; afterwards, it decreased by ∼30% during 2001–2013, reflecting the effectiveness of the ban on leaded gasoline in 2000. However, there was a slight increase in recent years. Therefore, it is critical to establish a comprehensive evaluation and monitoring system, strengthen pollution source control, properly manage the environmental and health risks at severely contaminated sites, and conduct green and sustainable remediation.

The gut microbiota plays a critical role in various physiologic processes; however, maternal microbial and metabolic changes during pregnancy and lactation remain elusive. Using pigs as an animal model, we conducted comparative analyses of gut microbiota and short-chain fatty acid (SCFA) profiles across different stages of gestation, lactation, and the empty (nonpregnancy) phase in 2 distinct breeds of sow, Rongchang (RS) and Landrace (LS). Coriobacteriaceae were found to gradually increase over gestational time irrespective of breed, which was further validated in an independent cohort of sows, indicating that Coriobacteriaceae are likely associated with the progression of pregnancy. Escherichia increased as well. Relative to empty and gestation, lactation was associated with an increase in SCFA producers and a concomitant augmentation in SCFA production in both breeds. A comparison between the 2 breeds revealed that Ruminococcaceae were more abundant in RSs than in LSs, consistent with the strong ability of Rongchang pigs to digest highly fibrous feedstuffs. Taken together, we revealed characteristic structural and metabolic changes in maternal gut microbiota throughout pregnancy, lactation, and the empty phase, which could potentially help improve the pregnancy and lactation outcomes for both animals and humans.-Liu, H., Hou, C., Li, N., Zhang, X., Zhang, G., Yang, F., Zeng, X., Liu, Z., Qiao, S. Microbial and metabolic alterations in gut microbiota of sows during pregnancy and lactation.

BACKGROUND: Intramuscular fat (IMF) is one of the most important factors positively associated with meat quality. Triglycerides (TGs), as the main component of IMF, play an essential role in muscle lipid metabolism. This transcriptome analysis of pectoralis muscle tissue aimed to identify functional genes and biological pathways likely contributing to the extreme differences in the TG content of broiler chickens. RESULTS: The study included Jingxing-Huang broilers that were significantly different in TG content (5.81 mg/g and 2.26 mg/g, p < 0.01) and deposition of cholesterol also showed the same trend. This RNA sequencing analysis was performed on pectoralis muscle samples from the higher TG content group (HTG) and the lower TG content group (LTG) chickens. A total of 1200 differentially expressed genes (DEGs) were identified between two groups, of which 59 DEGs were related to TG and steroid metabolism. The HTG chickens overexpressed numerous genes related to adipogenesis and lipogenesis in pectoralis muscle tissue, including the key genes ADIPOQ, CD36, FABP4, FABP5, LPL, SCD, PLIN1, CIDEC and PPARG, as well as genes related to steroid biosynthesis (DHCR24, LSS, MSMO1, NSDHL and CH25H). Additionally, key pathways related to lipid storage and metabolism (the steroid biosynthesis and peroxisome proliferator activated receptor (PPAR) signaling pathway) may be the key pathways regulating differential lipid deposition between HTG group and LTG group. CONCLUSIONS: This study showed that increased TG deposition accompanying an increase in steroid synthesis in pectoralis muscle tissue. Our findings of changes in gene expression of steroid biosynthesis and PPAR signaling pathway in HTG and LTG chickens provide insight into genetic mechanisms involved in different lipid deposition patterns in pectoralis muscle tissue.

Sperm cryopreservation is a powerful tool for the livestock breeding program. Several technical attempts have been made to enhance the efficiency of spermatozoa cryopreservation in different farm animal species. However, it is well-recognized that mammalian spermatozoa are susceptible to cryo-injury caused by cryopreservation processes. Moreover, the factors leading to cryo-injuries are complicated, and the cryo-damage mechanism has not been methodically explained until now, which directly influences the quality of frozen-thawed spermatozoa. Currently, the various OMICS technologies in sperm cryo-biology have been conducted, particularly proteomics and transcriptomics studies. It has contributed while exploring the molecular alterations caused by cryopreservation, identification of various freezability markers and specific proteins that could be added to semen diluents before cryopreservation to improve sperm cryo-survival. Therefore, understanding the cryo-injury mechanism of spermatozoa is essential for the optimization of current cryopreservation processes. Recently, the application of newly-emerged proteomics and transcriptomics technologies to study the effects of cryopreservation on sperm is becoming a hotspot. This review detailed an updated overview of OMICS elements involved in sperm cryo-tolerance and freeze-thawed quality. While also detailed a mechanism of sperm cryo-injury and utilizing OMICS technology that assesses the sperm freezability potential biomarkers as well as the accurate classification between the excellent and poor freezer breeding candidate.

Background: The genetic basis of animal domestication remains poorly understood, and systems with substantial phenotypic differences between wild and domestic populations are useful for elucidating the genetic basis of adaptation to new environments as well as the genetic basis of rapid phenotypic change. Here, we sequenced the whole genome of 78 individual ducks, from two wild and seven domesticated populations, with an average sequencing depth of 6.42X per individual. Results: Our population and demographic analyses indicate a complex history of domestication, with early selection for separate meat and egg lineages. Genomic comparison of wild to domesticated populations suggests that genes that affect brain and neuronal development have undergone strong positive selection during domestication. Our FST analysis also indicates that the duck white plumage is the result of selection at the melanogenesis-associated transcription factor locus. Conclusions: Our results advance the understanding of animal domestication and selection for complex phenotypic traits.

The mammalian intestine is the largest immune organ that contains the intestinal stem cells (ISC), differentiated epithelial cells (enterocytes, Paneth cells, goblet cells, tuft cells, etc.), and gut resident-immune cells (T cells, B cells, dendritic cells, innate lymphoid cell, etc.). Inflammatory bowel disease (IBD), a chronic inflammatory disease characterized by mucosa damage and inflammation, threatens the integrity of the intestine. The continuous renewal and repair of intestinal mucosal epithelium after injury depend on ISCs. Inflamed mucosa healing could be a new target for the improvement of clinical symptoms, disease recurrence, and resection-free survival in IBD treated patients. The knowledge about the connections between ISC and immune cells is expanding with the development of in vitro intestinal organoid culture and single-cell RNA sequencing technology. Recent findings implicate that immune cells such as T cells, ILCs, dendritic cells, and macrophages and cytokines secreted by these cells are critical in the regeneration of ISCs and intestinal epithelium. Transplantation of ISC to the inflamed mucosa may be a new therapeutic approach to reconstruct the epithelial barrier in IBD. Considering the links between ISC and immune cells, we predict that the integration of biological agents and ISC transplantation will revolutionize the future therapy of IBD patients.

Abstract Background Meat quality is an important economic trait in chickens. To identify loci and genes associated with meat quality traits, we conducted a genome-wide association study (GWAS) of F2 populations derived from a local Chinese breed (Beijing-You chickens) and a commercial fast-growing broiler line (Cobb-Vantress). Results In the present study, 33 association signals were detected from the compressed mixed linear model (MLM) for 10 meat quality traits: dry matter in breast muscle (DM Br ), dry matter in thigh muscle (DM Th ), intramuscular fat content in breast muscle (IMF Br ), meat color lightness (L*) and yellowness (b*) values, skin color L*, a* (redness) and b* values, abdominal fat weight (AbFW) and AbFW as a percentage of eviscerated weight (AbFP). Relative expressions of candidate genes identified near significant signals were compared using samples of chickens with High and Low phenotypic values. A total of 14 genes associated with IMF Br , meat color L*, AbFW, and AbFP, were differentially expressed between the High and Low phenotypic groups. These genes are, therefore, prospective candidate genes for meat quality traits: protein tyrosine kinase ( TYRO3 ) and microsomal glutathione S-transferase 1 ( MGST1 ) for IMF Br ; collagen, type I, alpha 2 ( COL1A2 ) for meat color L*; and RET proto-oncogene ( RET ), natriuretic peptide B ( NPPB ) and sterol regulatory element binding transcription factor 1 ( SREBF1 ) for the abdominal fat (AbF) traits. Conclusions Based on the association signals and differential expression of nearby genes, 14 candidate loci and genes for IMF Br , meat L* and b* values, and AbF are identified. The results provide new insight into the molecular mechanisms underlying meat quality traits in chickens.

An experiment was conducted to estimate the optimal dietary zinc level for broiler chicks fed a corn-soybean meal diet. A total of 384 one-day-old male broiler chicks were assigned randomly to dietary treatments for 21 d. These treatments included a basal corn-soybean meal diet (28.32 mg of Zn/kg) supplemented with 0, 20, 40, 60, 80, 100, 120, or 140 mg of Zn/kg in the form of reagent-grade ZnSO(4).7H(2)O. All treatments were replicated 6 times using 8 chicks per pen. Tissue Zn concentration, Zn metalloenzyme activity, metallothionein (MT) concentration, MT mRNA level, and Zn transporter-2 (ZnT-2) mRNA level were analyzed for choosing suitable criterion to determine the optimal dietary Zn level for broilers. Regression analysis was performed to estimate optimal dietary Zn level in the presence of quadratic or asymptotic responses. Results showed that weight gain and feed intake were increased with dietary Zn level (P < 0.05), and the maximum weight gain and feed intake were observed in the diet supplemented with 20 mg of Zn/kg (48.37 mg/kg, total dietary Zn). Pancreas MT and MT mRNA increased linearly with Zn supplementation. According to the asymptotic model, the optimal Zn requirement of chicks from hatch to 21 d of age was 59.15 mg/kg for pancreas Zn and 61.70 mg/kg for bone Zn respectively. Quadratic responses were exhibited by serum 5'-nucleotidase activity and pancreas Zn transporter-2 mRNA level, resulting in total optimal dietary levels of 80.50 and 84.09 mg/kg, respectively. Based on results from this study, the optimal dietary Zn level of chicks from hatch to 21 d of age is 84 mg/kg.

To investigate the effects of Clostridium butyricum on growth performance, antioxidation, and immune function of broilers, 320 one-day-old Arbor Acres commercial male chicks were assigned to one of 5 treatments with 8 replicates in a completely randomized design for 42 d. The 5 treatments were basal diet (control), basal diet supplemented with 2.5×10(8) cfu C. butyricum/kg (CB1), basal diet supplemented with 5×10(8) cfu C. butyricum/kg (CB2), basal diet supplemented with 1×10(9) cfu C. butyricum/kg (CB3), and basal diet supplemented with 150 mg aureomycin/kg (antibiotic). The results showed that all C. butyricum-supplemented groups during d 1 to 21 and the CB2 group during d 22 to 42 had higher ADG compared with the control (P<0.05). Chicks fed the CB3 diet had higher glutathione S-transferase (GST) activity (P<0.05), and chicks fed the CB2 diet had a higher glutathione (GSH) concentration in duodenal and ileal mucosa at 21 d of age than those in the control group (P<0.05). Chicks fed the CB3 diet had a lower malondialdehyde (MDA) concentration in duodenal mucosa than those in the control and CB1 groups (P<0.05). Chicks fed the CB2, CB3, and antibiotic diets had a lower MDA concentration in ileal mucosa than those in the control and CB1 groups (P<0.05). Broilers fed the CB3 diet had greater superoxide dismutase (SOD) activity in the ileal mucosa on d 21 and in jejunal mucosa on d 42 than those in the other groups (P<0.05). Chicks fed the CB2, CB3, and antibiotic diets had a higher GSH concentration in duodenal and jejunal mucosa on d 42 than those in the control group (P<0.05). Broilers fed the CB2 and CB3 diets had a lower MDA concentration in the jejunal mucosa on d 42 than those in the control and CB1 groups. Chicks fed diets supplemented with C. butyricum had a higher IgM concentration than those in the control group at 21 and 42 d of age (P<0.05). The results indicate that C. butyricum improves broilers' growth performance, antioxidation, and immune function.

Transcripts and protein for follicle-stimulating hormone receptor (FSHR) were demonstrated in abdominal adipose tissue of female chickens. There was no expression of the Fsh gene, but FSH and FSHR colocalized, suggesting that FSH was receptor bound. Partial correlations indicted that changes in abdominal fat (AF) content were most directly correlated with Fshr mRNA expression, and the latter was directly correlated with tissue FSH content. These relationships were consistent with FSH inducing Fshr mRNA expression and with the finding that FSH influenced the accumulation of AF in chickens, a novel role for the hormone. Chicken preadipocytes responded linearly to doubling concentrations of FSH in Fshr mRNA expression and quantities of FSHR and lipid, without discernable effect on proliferation. Cells exposed to FSH more rapidly acquired adipocyte morphology. Treatment of young chickens with chicken FSH (4 mIU/day, subcutaneous, days 7-13) did not significantly decrease live weight but increased AF weight by 54.61%, AF as a percentage of live weight by 55.45%, and FSHR transcripts in AF by 222.15% (2 h after injection). In cells stimulated by FSH, genes related to lipid metabolism, including Rdh10, Dci, RarB, Lpl, Acsl3, and Dgat2, were expressed differentially, compared with no FSH. Several pathways of retinal and fatty acid metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling changed. In conclusion, FSH stimulates lipid biosynthesis by upregulating Fshr mRNA expression in abdominal adipose tissue of chickens. Several genes involved in fatty acid and retinal metabolism and the PPAR signaling pathway mediate this novel function of FSH.