Function In Chickens Research Articles

Effects of Chinese Herbal Medicines on Lipid Metabolism and Immunity Function in Laying Hens

Background: Lipid is considered as one of the essential nutrients for both humans and animals. Lipid accumulation within the body may induce several health disorders. Disease is are caused easily in aged laying hens. It is necessary to improve lipid metabolism and enhance immunity in laying hens. Traditional Chinese veterinary medicine (TCVM) with no toxicity and low drug residues is becoming more and more popular. The current study aimed to study the effect of Chinese herbal medicines on lipid metabolism and immunity function in chicken to provide basis for clinical reference. Methods: In this laboratory investigation during 2018-2019, a total of 400 60-week-old hens were randomized into 10 groups to measure lipid metabolism by colorimetry and immunoglobulin by double antibody sandwich ELISA method. A total of 500 28-day-age chickens were randomized into 10 groups to measure immune organ index. The experiment lasted for 42 days. Result: Our investigations have showed that Jujube (ZJM) has significant effects on the count of Serum total cholesterol (TC), Triglyceride (TG), Low-density lipoprotein-c (LDL-C) and High-density lipoprotein-c (HDL-C) (p less tha 0.01, p less than 0.05),the count of Immunoglobulin-G (IgG) (p less than 0.05) and the immune organ indexes (p less than 0.05) in 30 mg/kg group than control group10.The present work will be a complementary contribution to the ability of ZJM on improving lipid metabolism and immunity function in chickens.

Bamboo leaf flavone changed the community of cecum microbiota and improved the immune function in broilers

It has been shown that bamboo leaf flavone (BLF) displays biological and pharmacological activities in mammals. However, the effects of BLF on broiler gut microbiota and related immune function have not been investigated. The aim of this study was to test our hypothesis that BLF can improve the health status of broilers by modulating the gut microbiota. A total of 300 one-day-old Arbor Acres (AA) broilers were used to characterize their gut microbiota and immune status after feeding diet supplemented with BLF. The V4 hypervariable region of the 16S rRNA gene from cecal bacteria was sequenced via the Illumina MiSeq platform. The Immune status and related parameters were assessed, including the immune organ index (the spleen, thymus, and bursa), serum concentrations of IL-2 and INF-γ, and spleen IL-2 and INF-γ gene expressions. The results showed the BLF diet had an Immune enhancement effect on broilers. In addition, BFL caused the changes of the gut microbial community structure, resulting in greater proportions of bacterial taxa belonging to Lactobacillus, Clostridiales, Ruminococcus, and Lachnospiraceae. These bacteria have been used as probiotics for producing short chain fatty acids in hosts. These results indicate that BLF supplement improves immune function in chicken via modulation of the gut microbiota.

Effect of delayed feeding post-hatch on expression of tight junction– and gut barrier–related genes in the small intestine of broiler chickens during neonatal development

The gut not only plays a key role in digestion and absorption of nutrients but also forms a physical barrier and first line of defense between the host and the luminal environment. A functional gut barrier (mucus and epithelial cells with tight junctions [TJ]) is essential for optimal health and efficient production in poultry. In current broiler system, chicks are deprived of food and water up to 72 h due to uneven hatching, hatchery procedures, and transportation. Post-hatch feed delay results in lower BW, higher FCR and mortality, and delayed post-hatch gut development. Little is known about the effects of early neonatal development and delayed feeding immediately post-hatch on gut barrier function in chickens. Therefore, the aim of the present study was to characterize the expression pattern of gut barrier–related and TJ-related genes in the small intestine of broiler chickens during early development and delay in access to feed. Newly hatched chicks received feed and water immediately after hatch or were subjected to 48 h delayed access to feed to mimic commercial hatchery setting and operations. Birds were sampled (n = 6) at −48, 0, 4, 24, 48, 72, 96, 144, 192, 240, 288, and 336 h post-hatch. Jejunum and ileum were collected, cleaned of digesta, and snap-frozen in liquid nitrogen or fixed in paraformaldehyde. The relative mRNA levels of gut barrier- and TJ-related protein genes were measured by quantitative PCR and analyzed by 2-way ANOVA. In both tissues, changes (P < 0.05) in gene expression pattern of gut barrier–related and TJ-related genes were detected due to delayed access to feed post-hatch and/or development. In general, expression of TJ-related genes was downregulated while mRNA levels of gut barrier-related genes were upregulated during development. Histological differences and changes in mucin staining due to age and treatment were observed. These results suggest that delayed access to feed post-hatch may affect TJ structure and/or function and therefore gut barrier function and overall health of the chicken small intestine.

Florfenicol induces oxidative stress and hepatocyte apoptosis in broilers via Nrf2 pathway.

In order to explore the mechanism of liver injury induced by florfenicol (FFC) in broilers, one hundred and twenty broilers were randomly divided into six groups, twenty broilers in each group. Except for control group, the other five groups were given different doses of FFC (0.15g/L, 0.3g/L, 0.6g/L, 1.2g/L and 1.8g/L) in drinking water. After five days of continuous use, blood was collected from the subpterional vein and the chickens' liver were obtained. Chicken weight gain and liver indices were calculated; blood routine analysis was performed; the oxidative stress and apoptosis of hepatocytes was detected. The results showed that compared with the control group, except for 0.15g/L FFC, the other doses of FFC significantly decreased the weight gain, white blood cell (WBC) and platelet (PLT) contents in blood, 0.3g/mL FFC and 1.8g/L FFC significantly reduced the content of hemoglobin (RGB) (P<0.05); all doses of FFC significant decreased red blood cell (RBC) increased Alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) contents in serum of chickens (P<0.05), and significantly decreased the contents of albumin (ALB) and total protein (TP) in serum (P<0.05), but had no significant effect on alkaline phosphatase (ALP) contents(P>0.05). FFC significantly increased malondialdehyde (MDA) content in serum and liver tissues, but decreased glutathione (GSH), Superoxide dismutase (SOD) and catalase (CAT) content (P<0.05), and significantly inhibited the mRNA transcription and protein expression of antioxidant proteins nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase quinone-1 (NQO-1)(P<0.05). FFC also inhibited the content and the transcription level of cytochrome P4501A1(CYP1A1) and CYP2H1 in liver (P<0.05). At the same time, FFC significantly promoted the apoptotic rate of hepatocytes and the mRNA transcription and protein expression of caspase-3 and caspase-6 (P<0.05). With the increase of FFC concentration, liver injury became more and more serious, which affected liver function in chickens by inhibiting enzyme activity in Nrf2-ARE pathway to increase oxidative stress and promoting apoptotic protein expression to accelerate hepatocyte apoptosis.

Selenium Deficiency in Chickens Induces Intestinal Mucosal Injury by Affecting the Mucosa Morphology, SIgA Secretion, and GSH-Px Activity.

The small intestine is one of the target organs of dietary selenium (Se) deficiency. Our objective was to investigate the effects of Se deficiency on small intestinal mucosa morphology and function in chickens. In the present study, 1-day (d)-old chickens were fed either a commercial diet with 0.15mg/kg Se (control group) or a Se-deficient diet with 0.016mg/kg Se (Se-group). The average daily weight gain, Se content in the blood, secretory immunoglobulin A (SIgA) secretion, and glutathione peroxidase (GSH-Px) activity in the small intestine in chickens were examined after 10, 20, 30, and 40days of feeding. We also observed the morphology of the small intestine and recorded the number of intraepithelial lymphocytes (IELs). The average daily weight gain decreased; the level of Se in the blood decreased significantly; and SIgA secretion and GSH-Px activity in the duodenum, jejunum, and ileum decreased to different degrees. Histological analysis showed that the villus length, crypt depth, mucosal thickness, and number of IELs in the small intestine decreased to different extents in different periods. In the Se-group, longer feeding times were associated with more severe injury to physiological structure and function in the intestinal mucosa in chickens. In conclusion, Se deficiency induced injury of the mucosal immune barrier and physical barrier of the small intestine, and decreased the growth performance and antioxidant capacity in chickens.

Effects of Oral Administration of Lactobacillus reuteri on Mucosal Barrier Function in the Digestive Tract of Broiler Chicks.

Probiotic bacteria are known for their beneficial effects on the intestinal immune function of the host animal. However, their effects on mucosal barrier function in chicks are not completely understood. The aim of this study was to determine the effects of the probiotic bacterium, Lactobacillus reuteri (LR), on the gastrointestinal mucosal barrier function of broiler chicks. One day-old male broiler chicks were orally injected water (300 µL) with or without 1 × 108 cfu of LR (5 mg FINELACT, Asahi Calpis Wellness Co. Ltd.) every morning for 7 days (day 0 to 6). The crop, duodenum, ileum, and cecum were collected on day 7 and were used for histological analysis and RNA extraction. Then, the thickness of the mucosal structures and the number of goblet cells in the digestive tract were assessed using histological analysis. The expression of Mucin 2, factors related to the formation of tight junctions (Claudin1, 5, and 16, ZO2, and JAM2), cytokines (IL-6, CXCLi2, and IL-10), and avian β-defensin 10 (AvBDs) (AvBD2, 10, and 12) in the crop, duodenum, ileum, and cecum were analyzed using real-time polymerase chain reaction (PCR). Results showed that oral administration of LR increased ileal villus height and crypt depth, decreased Claudin16 level in the crop and increased JAM2 level in the crop and ileum, and decreased the expression of AvBD10 in the ileum and cecum and that of AvBD12 in the crop. It did not affect goblet cell number and Mucin 2 expression. These results suggested that LR used in this study may enhance mucosal barrier function by regulating tight junctions in the upper gastrointestinal tract.

Pancreatic Exocrine Function in Chickens

The pancreatic secretory response to the Garlic allicin dietary supplement under the conditions of an experiment with chickens implanted with pancreatic duct chronic fistulas has been studied. The results prove that the amylolytic and proteolytic activities increase the secretion at 1 mL in chickens in the test period (8 days). However, there is no significant change in the total volume of juice for 180 minutes. The analysis of the adaptation mechanism in the postprandial phase indicates an enzyme activity increase in the complex reflective cycle caused by both the receptors responding to the food tastes and the conditioned reflex factors. The adaptation developed within 8 days is associated with a sharp (twofold) increase in the proteolytic activity on the third day and the following proteinase activity decrease up to the initial rate of the enzyme activity.

The Role of Nitric Oxide in the Exocrine Pancreatic Function in Chicken

The universal cell mediator nitric oxide (NO) mediating the physiological effects via so-called NO donor compounds prolonging its life time. The concentration of NO metabolites in the pancreatic juice of chicken was determined by the enzymatic sensor. It was found that pancreatic juice from starved birds contains nitrate and no other nitro- or nitroso compounds. After feeding, the NO donors appear in pancreatic juice in concentrations of a few tens of μM. These compounds were present in pancreatic juice for several hours after feeding. It is possible that NO donors promote relaxation of the smooth muscles in the walls of pancreatic ducts. Concentration of NO donors in blood serum also increased 2.5–3.0-fold after feeding and remained high during a few subsequent hours. The preliminary subcutaneous administration of atropine to the birds prevent this increase with no effects on the initial concentrations of NO donors in serum. This suggests that the increase is associated with cholinergic stimulation and, therefore, with the activity of the parasympathetic nervous system. The concentration of trypsin in serum also increased after feeding, and atropine also prevents this increase. It is known that serum trypsin acts as a regulator of pancreatic function. Intravenous administration of trypsin led to an insignificant increase of tryptic activity in serum but induced the increase of NO donor concentration twofold. Apparently, nitric oxide, represented by these compounds, can act as a humoral factor in the regulation of pancreatic function in pancreatic juice and possibly in the blood.

The role of nitric oxide in the exocrine pancreatic function in chicken

The role of nitric oxide in the exocrine pancreatic function in chicken

Responses to dietary levels of methionine in broilers medicated or vaccinated against coccidia under Eimeria tenella-challenged condition

BackgroundCoccidiosis is a prevalent problem in chicken production. Dietary addition of coccidiostats and vaccination are two approaches used to suppress coccidia in the practical production. Methionine (Met) is usually the first limiting amino acid that plays important roles in protein metabolism and immune functions in chickens. The present study is aimed to investigate whether increasing dietary Met levels will improve the anticoccidial effects in broilers medicated or vaccinated against coccidia under Eimeria (E.) tenella-challenged condition. Two thousand male Partridge Shank broiler chicks were obtained from a hatchery. After hatch, birds were weighed, color-marked and allocated equally into two anticoccidial treatments, namely medicated and vaccinated groups. Chicks were either fed, from 1 d of age, diets containing coccidiostat (narasin) or diets without the coccidiostat but were inoculated with an anticoccidial vaccine at 3 d of age. At 22 d of age, 1080 chicks among them were randomly allocated evenly into 6 groups under a 2 × 3 treatment with 2 anticoccidial programs and 3 dietary methionine (Met) levels. Chicks medicated or vaccinated against coccidia were fed diets containing 0.45%, 0.56% or 0.68% of Met from 22 to 42 d of age. All chicks were orally introduced with an amount of 5 × 104 sporulated oocysts of E. tenella at 24 d of age. The growth performance, serum anti-oxidative indexes, intestinal morphology, cecal lesion scores, fecal oocyst counts and immune parameters were measured.ResultsThe results showed increasing dietary Met level from 0.45% to 0.56% and 0.68% improved weight gain and feed conversion of broilers medicated against coccidia. In contrast, higher dietary levels of Met did not improve growth performance of the vaccinated chickens. Higher Met levels helped the medicated chickens resist E. tenella infection, as indicated by improved intestinal morphology and immune functions as well as decreased cecal lesion and fecal oocyst counts.ConclusionsAnticoccidial vaccination is a better strategy for controlling coccidiosis than feeding narasin, due to not only greater growth performance, but also the lower Met supplementation. Furthermore, higher dietary Met levels improved growth performance of chickens medicated rather than vaccinated against coccidia under E. tenella-challenged condition.

New Approaches to Evaluation of Digestive Function in Chickens

The activity of digestive enzymes in the blood of chickens has been studied using the current biochemical methods. The digestive enzyme activity level in blood is proven to be associated with intestinal function. Typsin is the most volatile digestive enzyme since its activity significantly increases 1 h after the feed intake. The calculation of the blood digestive enzyme index as the ratio of the total lipase and amylase activities to the trypsin activity has been proposed to evaluate the physiological condition and health of the digestive system in the animals.

Melatonin modulates monochromatic light-induced melatonin receptor expression in the hypothalamus of chicks

To study the mechanism of the effect of monochromatic light on physiological function in chicken, a total of 192 newly hatched chicks were randomly divided into intact, sham-operated and pinealectomy groups then exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) using a light-emitting diode (LED) system for two weeks. At P14, the hypothalami were immediately collected for immunohistochemical staining of melatonin receptor subtypes (Mel1a and Mel1b) and detection of Mel1a and Mel1b expressions using RT-PCR and western blot. Immunohistochemical staining of the hypothalamus showed that the Mel1a-ir cells were distributed in the preoptic area (POA), nucleus preopticus periventricularis (POP) and suprachiasmatic nuclei (SCN), and the Mel1b-ir cells were presented in the POA and SCN. Analysis of RT-PCR and western blot showed that the mRNA and protein levels of Mel1a and Mel1b in the hypothalamus of chick exposed to GL were increased by 10.7–29.3%, 9.18–35.9% and 8.97–27.3% compared to those in the chicks exposed to WL (P=0.029–0.002), RL (P=0.027–0.001) and BL (P=0.038–0.007) in the intact group, respectively. After pinealectomy, however, these parameters decreased and there were no significant differences among the WL, RL, GL and BL groups. These findings suggested that melatonin plays a critical role in GL illumination-enhanced Mel1a and Mel1b expressions in the hypothalamus of chicks.

Effects of poorly hydrolizable ingredients in mixed feeds on pancreatic exocrine function in chickens

The response of the pancreas to the use of the poorly hydrolysable ingredients (wheat bran and sunflower meal) in the mixed feed diet was shown under the conditions of the chronic experiments on chickens. The proteolytic enzyme activity decreases by 22–36% as compared to the control because of a 10% decrease in the dietary crude protein level. The lipase activity increases by 17–26% due to an increase in the dietary crude fat content, while the amylase activity remains significantly unchanged with an increase in the dietary amount of nonstarch polysaccharides. The process of the pancreatic adaptation to the new dietary feed generally occurs through a change in the activity of pancreatic enzymes rather than the volume of pancreatic juice. This can indicate the fine adjustment of the digestive system to any change in feed quality.

Enteric Pathogens and Their Toxin-Induced Disruption of the Intestinal Barrier through Alteration of Tight Junctions in Chickens.

Maintaining a healthy gut environment is a prerequisite for sustainable animal production. The gut plays a key role in the digestion and absorption of nutrients and constitutes an initial organ exposed to external factors influencing bird’s health. The intestinal epithelial barrier serves as the first line of defense between the host and the luminal environment. It consists of a continuous monolayer of intestinal epithelial cells connected by intercellular junctional complexes which shrink the space between adjacent cells. Consequently, free passing of solutes and water via the paracellular pathway is prevented. Tight junctions (TJs) are multi-protein complexes which are crucial for the integrity and function of the epithelial barrier as they not only link cells but also form channels allowing permeation between cells, resulting in epithelial surfaces of different tightness. Tight junction’s molecular composition, ultrastructure, and function are regulated differently with regard to physiological and pathological stimuli. Both in vivo and in vitro studies suggest that reduced tight junction integrity greatly results in a condition commonly known as “leaky gut”. A loss of barrier integrity allows the translocation of luminal antigens (microbes, toxins) via the mucosa to access the whole body which are normally excluded and subsequently destroys the gut mucosal homeostasis, coinciding with an increased susceptibility to systemic infection, chronic inflammation and malabsorption. There is considerable evidence that the intestinal barrier dysfunction is an important factor contributing to the pathogenicity of some enteric bacteria. It has been shown that some enteric pathogens can induce permeability defects in gut epithelia by altering tight junction proteins, mediated by their toxins. Resolving the strategies that microorganisms use to hijack the functions of tight junctions is important for our understanding of microbial pathogenesis, because some pathogens can utilize tight junction proteins as receptors for attachment and subsequent internalization, while others modify or destroy the tight junction proteins by different pathways and thereby provide a gateway to the underlying tissue. This review aims to deliver an overview of the tight junction structures and function, and its role in enteric bacterial pathogenesis with a special focus on chickens. A main conclusion will be that the molecular mechanisms used by enteric pathogens to disrupt epithelial barrier function in chickens needs a much better understanding, explicitly highlighted for Campylobacter jejuni, Salmonella enterica and Clostridium perfringens. This is a requirement in order to assist in discovering new strategies to avoid damages of the intestinal barrier or to minimize consequences from infections.

Genetic Manipulation of the Avian Urogenital System Using In Ovo Electroporation.

One of the advantages of the avian embryo as an experimental model is its in ovo development and hence accessibility for genetic manipulation. Electroporation has been used extensively in the past to study gene function in chicken and quail embryos . Readily accessible tissues such as the neural tube, somites, and limb bud, in particular, have been targeted. However, more inaccessible tissues, such as the embryonic urogenital system , have proven more challenging to study. Here, we describe the use of in ovo electroporation of TOL2 vectors or RCASBP avian viral vectors for the rapid functional analysis of genes involved in avian sex determination and urogenital development . In the context of the developing urogenital system , these vectors have inherent advantages and disadvantages, which will be considered here. Either vector can both be used for mis-expressing a gene and for targeting endogenous gene knockdown via expression of short hairpin RNAs (shRNAs). Both of these vectors integrate into the genome and are hence spread throughout developing tissues. Going forward, electroporation could be combined with CRISPR/Cas9 technology for targeted genome editing in the avian urogenital system .

Genome-wide association study reveals novel variants for growth and egg traits in Dongxiang blue-shelled and White Leghorn chickens.

This study was designed to investigate the genetic basis of growth and egg traits in Dongxiang blue-shelled chickens and White Leghorn chickens. In this study, we employed a reduced representation sequencing approach called genotyping by genome reducing and sequencing to detect genome-wide SNPs in 252 Dongxiang blue-shelled chickens and 252 White Leghorn chickens. The Dongxiang blue-shelled chicken breed has many specific traits and is characterized by blue-shelled eggs, black plumage, black skin, black bone and black organs. The White Leghorn chicken is an egg-type breed with high productivity. As multibreed genome-wide association studies (GWASs) can improve precision due to less linkage disequilibrium across breeds, a multibreed GWAS was performed with 156575 SNPs to identify the associated variants underlying growth and egg traits within the two chicken breeds. The analysis revealed 32 SNPs exhibiting a significant genome-wide association with growth and egg traits. Some of the significant SNPs are located in genes that are known to impact growth and egg traits, but nearly half of the significant SNPs are located in genes with unclear functions in chickens. To our knowledge, this is the first multibreed genome-wide report for the genetics of growth and egg traits in the Dongxiang blue-shelled and White Leghorn chickens.

The Sterilized Fermented Feed Improves Intestinal Barrier Function and Immune Function in Chicken

The objective of this study was to evaluate the effects of dietary addition of fermentation metabolites by Sterilized fermented feed(SFF) as a replacement for fermented feed(FF) and antibiotics on expression of genes related intestinal barrier function and immune parameters in chicken. Three hundred and ninety‐six 1‐d‐old broilers with body weight of 41.27 ± 0.49 g were randomly allotted into 4 dietary treatments: 1) Positive control: PC (basal diet + bacitracinzinc80 mg/kg feed + colistin sulfate 20mg/kg feed), 2) Negative control: NC (basal diet), 3) FT (basal diet + 2.0% FF), and 4) SFT (basal diet + 2.0% SFF). After trial, 8chickens from each treatment were randomly selected to collect serum and intestinal samples. Chickens in the PC groups had a decrease (P &lt; 0.05) in serum concentrations of lipopolysaccharide (LPS) compared with the NC, FT and SFT group, and there were no difference among group NC, FT and SFT. In the ileum, supplementation with SFF and FF down‐regulated (P&lt;0.05) the mRNA levels of tumor necrosis factor‐α (TNF‐α) andIL‐6 compared with the NC and PC group. Besides, supplementation with SFF up‐regulated(P&lt;0.05) the mRNA levels of Claudin‐1, Claudin‐3, Claudin‐5, zonula occludens1 (ZO‐1), zonula occludens 2 (ZO‐2), Toll‐like receptor 2 (TLR2), Toll‐like receptor 4 (TLR4), defensins AVBD‐9, mucin 2 (MUC2), secretory IgA (sIgA) and IL‐18 compared with the NC group. Furthermore, the mRNA levels of TLR2, AVBD‐9, Claudin‐3 and Claudin‐5 in group SET were lower (P&lt;0.05) than that of group FT but higher than (P&lt;0.05) group PC. And there were no difference on occluding among all groups. Collectively, the current results indicate that dietary addition of SFF has a beneficial influence on the health condition of chicken by improving intestinal barrier function and immune function. That indicated the probiotics is not the only ingredient that works and the fermentation metabolites should be paid more attention.Support or Funding InformationSanzhi Biotechnology Co. Ltd., Shanghai, China

Selenium Deficiency Mainly Influences Antioxidant Selenoproteins Expression in Broiler Immune Organs.

Selenoprotein has many functions in chicken, and the expression of selenoproteins is closely associated with the selenium (Se) level. However, little is known about the expression patterns of selenoproteins in chicken immune organs. Here, we investigated the effect of dietary Se deficiency on the expressions of 23 selenoproteins in broiler immune organs. In this study, 150 broilers were randomly divided into two groups (75 chickens per group). The chickens were maintained either on a diet supplemented with Se through the addition of 0.2mg/kg of Se (C group) via sodium selenite or on a Se-deficient granulated diet (L group) until the broilers exhibited an onset of exudative diathesis (ED). Following euthanasia, the samples from the immune tissues (including the spleen, thymus, and bursa of Fabricius) were quickly collected, and the messenger RNA (mRNA) expression levels of 23 selenoproteins were examined by real-time quantitative PCR and analyzed using principal component analysis. The results showed that Se deficiency decreased the mRNA levels of 23 selenoproteins in the thymus, spleen, and bursa of the Fabricius tissues of broiler chickens. Furthermore, we found that among 23 selenoproteins, the mRNA levels of Dio1 in the thymus, Txnrd2 in the spleen, and Txnrd3 in the bursa of Fabricius decreased significantly (90.9%, 83.3%, and 96.8%, respectively). In addition, the principal component analysis (PCA) results suggested that Se deficiency mainly influenced the expression of antioxidative selenoproteins, especially glutathione peroxidases (Gpxs), thioredoxin reductases (Txnrds), and iodothyronine deiodinases (Dios) in chicken immune organs. The results of this study are valuable for understanding the relevance of selenoprotein activity in vivo.

Effect of Dietary Selenium Deficiency on the Cell Apoptosis and the Level of Thyroid Hormones in Chicken.

This study assessed the effect of dietary selenium (Se) deficiency on male reproductive function in chicken. A total of 180 Hy-line laying cocks (1day old; Weiwei) were randomly divided into 2 groups (n=90) of Se-deficient chickens and control chickens. The control group was fed a basic diet (containing 0.15mg of Se/kg). The Se-deficient group was fed a Se-deficient corn-soy basal diet (containing 0.033mg of Se/kg). Fifteen chickens were killed in each group on days 30, 60, and 90, respectively. Then, serum and testes were collected and used in the detection of experimental index. Results indicated that GSH-Px activity and Bcl-2 mRNA level in the testes and thyroidal triiodothyronine (T3) and free triiodothyronine (FT3) levels in serum by dietary Se deficiency were significantly decreased compared to the corresponding control groups. Se deficiency-treated group showed a significant increase in MDA concent, TUNEL-positive cells, and mRNA level of Bax, Caspase3, and p53 in the testes and thyroidal thyroxine (T4), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) levels in serum. Histopathologically, Se deficiency caused impairments in the testes. These results suggested that dietary Se deficiency exerts significant harmful effects on male reproductive organ and that the intrinsic and extrinsic pathways and the upstream regulators such as p53, Bax, and Bcl-2 were all involved in Se deficiency-induced testicular apoptosis.

The protective effect of γ-aminobutyric acid on the development of immune function in chickens under heat stress.

This study aimed to investigate the protective effect of γ-aminobutyric acid (GABA) on the development of immune function in chicks under heat stress (HS). One-day-old male Wenchang chicks were randomly divided into control (CK), HS and GABA+HS groups. The GABA+HS group was fed with 0.2ml GABA solution (50mg/kg) daily by oral gavage. The HS and GABA+HS groups were placed in 40±0.5°C environment for 2h heat treatment from 13:00 each day. Blood samples were routinely taken at 14, 21, 28, 35 and 42days respectively, and the contents of T and B lymphocyte subsets in the blood and tissue were analysed by flow cytometry after FITC/PE double staining; the plasma levels of interleukin (IL)-2, immunoglobulin (Ig)A, IgG and IgM were determined using ELISA. The thymus and the bursa of fabricius were also collected to analyse for organ index and observe for the changes in tissue microstructure. In addition, the chicks received primary and secondary immunizations with attenuated Newcastle disease (ND) vaccine (LaSota strain) at 7 and 28days respectively; conventional hemagglutination inhibition (HI) assay was performed to monitor the titre changes in plasma antibody against ND virus in the birds. Our results indicated that the indices of both thymus and bursa of fabricius, the intactness of tissue structure and development, the plasma levels of IL-2, IgA, IgG and IgM, the titres of ND antibody, and the levels of B and T lymphocyte subsets in HS group were all significantly lower than those in CK group (p<0.05). However, all above indices were significantly improved in GABA+HS group compared with those in HS group (p<0.05). These results demonstrated that while HS seriously affected the development of immune function in Wenchang chicks, GABA effectively alleviated the damages of HS to the development of immune function in chicks.