Effects of early weaning on intestinal morphology, digestive enzyme activity, antioxidant status, and cytokine status in domestic pigeon squabs (Columba livia)

The aim of this study was to explore the effects of early weaning on growth performance, intestinal morphology, digestive enzyme activity, antioxidant status, and cytokine status in domestic pigeon squabs (Columba livia). The conclusion is based on body weight (BW) and average daily gain (ADG), length index and weight index of small intestine, small intestinal morphology, activity of digestive enzymes in duodenum content, the concentrations of jejunal antioxidant status and cytokines. A completely randomized design with 2 treatments, the control group (CON) and early weaning (EW) group, was utilized. Eight squabs per treatment were sampled at the age of 25 d. The results showed that early weaning reduced BW (P < 0.05), ADG (P < 0.05), ileac length index (P < 0.05), and weight index (P < 0.01). Compared with the CON group, small intestinal morphology was altered in the EW group. Ileac crypt depth (CD) increased significantly (P < 0.01). The villus area was decreased in the duodenum (P < 0.05), jejunum (P < 0.01), and ileum (P < 0.05). The ileac ratio of villus height to crypt depth (VCR) in the EW group was lower than the ileac ratio of villus height to VCR in the CON group (P < 0.01). The activity of trypsin (P < 0.05), sucrase (P < 0.01) and aminopeptidase-N (APN) (P < 0.01) in the duodenum was reduced. Jejunal malondialdehyde (MDA) (P < 0.01) was increased and total superoxide dismutase (T-SOD) (P < 0.01) was reduced significantly. Early weaning decreased the concentrations of interferon-γ (IFN-γ) (P < 0.01), interleukin-4 (IL-4) (P < 0.05) and interleukin-10 (IL-10) (P < 0.01) but induced significant upregulation of interleukin-2 (IL-2) (P < 0.05). In conclusion, our results suggested that early weaning did harm the BW and ADG, intestinal length index and weight index, intestinal morphology, activity of digestive enzymes, and antioxidant and cytokine status.

H-FABP gene expression and genetic association with meat quality traits in domestic pigeons (Columba livia)

1. H-FABP (heart-type fatty acid-binding protein) is an important fatty acid-binding protein that participates in the metabolism and intracellular transportation of lipids. This study was designed to study the H-FABP gene expression and genetic association with meat quality traits in domestic pigeons.2. The spatio-temporal expression patterns showed that H-FABP was widely expressed in all eleven tissues in birds from hatching to 4 weeks of age, and the expression level in the liver was the highest, and spleen and subcutaneous fat showed relatively high levels at all time points, and increased markedly as squabs became older.3. Nine novel SNPs were found; three of them (g.42 C > T and g.123 C > T in exon 1 and g.3128 C > T in exon 2) were synonymous mutations, and six of them (g.3304 T > C, g.3305 G > A, g.3313A>G, g.3343 C > T, g.3372A>C, g.3410 T > C in exon 3) were located in the 3' untranslated region (UTR). In addition, four haplotypes and six diplotypes were formed and showed weak linkage disequilibrium. Association analysis showed that in the SNP of g.3305 G > A, the AB genotype showed higher (P < 0.05) inosinic acid concentrations in breast muscle than the BB genotype. In the SNP of g.3313A>G, the AA and AB genotypes showed significantly higher (P < 0.01) inosinic acid concentrations than the BB genotype, AA showed the highest intramuscular fat content, and the relative mRNA expression level of the AA genotype was the highest (P < 0.05).4. Association analysis of diplotypes showed no correlation with meat quality traits. Moreover, correlation analysis indicated that the H-FABP mRNA expression level was tightly related to intramuscular fat content (P < 0.01).5. This study suggested that the H-FABP gene may be a candidate gene in marker-assisted selection of pigeons for high-quality meat.

Effect of iron glycine chelate supplementation on egg quality and egg iron enrichment in laying hens

This study was conducted to evaluate the effects of iron glycine chelate (Fe-Gly) on egg quality of laying hens. A total of 810 laying hens (HyLine Variety White, 26 wk old) were randomly assigned to 6 groups, and each group consisting of 135 hens (5 replicates of 27 hens each). Hens in the control group received a diet supplemented with 60 mg Fe/kg as FeSO4, whereas hens in the other 5 groups received diets supplemented with 0, 20, 40, 60, and 80 mg Fe/kg from Fe-Gly, respectively. The study showed that dietary Fe-Gly treatments influenced (P < 0.05) the internal egg quality (egg weight, Haugh unit, albumen height), compared with the control group. However, dietary Fe-Gly supplementation showed few effects on the ultrastructure of eggshell in this study. The group of 60 mg Fe/kg as Fe-Gly was promoted (P < 0.05) in succinate dehydrogenase levels of liver and spleen compared with the 0 mg Fe-Gly/kg group, whereas the control (Fe/kg as FeSO4) group has no differences compared with the 0 mg Fe-Gly/kg group. The concentrations of Fe in the eggshell, yolk, and albumen were increased with increasing concentrations of Fe-Gly, where Fe-Gly (60, 80 mg Fe/kg) had higher (P < 0.01) Fe concentration than the control in yolk and albumen. The Fe-Gly groups (60, 80 mg Fe/kg) were influenced (P < 0.05) in transferrin, divalent mental transport 1, and ferroportin 1, compared with the control (FeSO4). In conclusion, Fe-Gly (60 mg Fe/kg) improved egg quality and egg iron enrichment. In general, there were no significant differences between Fe-Gly (40) and the control group in albumen height, Haugh unit, Fe concentration in eggshell and yolk. It revealed that FeSO4 could be substituted by a lower concentration of Fe-Gly and Fe-Gly may be superior to FeSO4 for egg quality in laying hens.

Excess dietary fluoride affects laying performance, egg quality, tissue retention, serum biochemical indices, and reproductive hormones of laying hens

The present study aimed to evaluate the effects of excess dietary fluoride (F) on laying performance, egg quality, tissue retention, serum biochemical indices, and serum reproductive hormones of laying hens. A total of 384 Hy-Line Gray hens, 37 wk old, were treated with sodium fluoride added to a corn-soybean meal basal diet at 0, 400, 800, and 1200 mg fluorine/kg feed. The results showed that dietary F levels at 800 and 1200 mg/kg markedly decreased ADFI, laying rate, average egg weight, and increased feed conversion ratio (FCR) (P < 0.05). Dietary F levels at 800 and 1200 mg/kg dramatically decreased the egg quality of albumen height, yolk color, eggshell strength, and eggshell thickness, and on the 49th D, 400 mg/kg F group significantly decreased the eggshell strength, compared to those of control group. Fluoride residues in tissues of hens were increased significantly with the increase of dietary F supplemental levels (P < 0.05). Fluoride concentrations were generally high in feces, eggshell, tibia, kidney, and ovary, and the highest in feces, following with eggshell and tibia, lower in kidney and ovary, and the lowest in serum. Serum uric acid levels and alanine aminotransferase activity increased significantly (P < 0.05), and glucose, triglycerides, and phosphorus decreased significantly (P < 0.05) in response to dietary F concentration, compared to those of the control group, respectively. Dietary F supplementation at 1200 mg/kg significantly decreased (P < 0.05) the estrogen concentrations in serum, compared to those of the control group. Concentrations of progesterone in the fluoride-treated groups were significantly (P < 0.05) decreased relative to those of the control group. In conclusion, these results indicated that the excessive ingestion of F has had a detrimental effect on egg laying rate and quality of eggs by damaging the function of the liver, kidney, and ovary of laying hens.

Histological changes, lipid metabolism, and oxidative and endoplasmic reticulum stress in the liver of laying hens exposed to cadmium concentrations

The objective of this study was to determine the effects of cadmium (Cd) on histological changes, lipid metabolism, and oxidative and endoplasmic reticulum (ER) stress in the liver of layers. A total of 480 hens at 38 wk of age were randomly assigned in 5 groups that were fed a basal diet or basal diet supplemented with CdCl₂ 2.5H₂O at 7.5, 15, 30, and 60 mg Cd/kg feed for 9 wk. The results showed that accumulation of Cd was the greatest in the kidney, followed by the liver, pancreas, and lung. Diet contaminated with 30 mg Cd/kg induced antioxidant defenses accompanied by the increase of the activities of antioxidant enzymes in the liver, while dietary supplementation with 60 mg Cd/kg decreased the antioxidant levels significantly (P < 0.05). Immunofluorescence assay showed Cd induced reactive oxygen species production and endoplasmic reticulum stress in hepatocytes. Exposure to 60 mg Cd/kg significantly upregulated the expression of cytochrome C, caspase 3, caspase 9, caspase 7, Grp78, and Chop (P < 0.05). Histopathology and quantitative real-time PCR results presented periportal fibrosis, bile duct hyperplasia, and periportal inflammatory cell infiltration in the liver accompanied by upregulating the expression of tumor necrosis factor-α, IL-6 and IL-10 in the 30- or 60-mg Cd/kg groups. Oil Red O staining and RT-qPCR results showed dietary supplementation with 7.5, 15, and 30 mg Cd/kg promoted the synthesis of lipid droplets and upregulated the expression of fatty acid synthase, while dietary supplementation with 60 mg Cd/kg attenuated the synthesis of lipid droplets and downregulated the expression of acyl-CoA oxidase 1, carnitine palmitoyltransferase-1, and perixisome proliferation-activated receptor α (P < 0.05). Besides, the expression of vitellogenin (VTG) II and microsomal triglyceride transfer protein were upregulated in the 7.5-mg Cd/kg group, and the expressions of apolipoprotein B, vitellogenin II, and apolipoprotein very-low-density lipoprotein-II were downregulated in the 30- and/or 60-mg Cd/kg groups (P < 0.05). Conclusively, although low-dose Cd exposure promoted the synthesis of lipids and lipoproteins in the liver, the increase of Cd exposure could trigger liver injury through inducing oxidative and endoplasmic reticulum stress and negatively affect lipid metabolism and yolk formation in laying hens.

Effects of parental dietary linoleic acid on growth performance, antioxidant capacity, and lipid metabolism in domestic pigeons (Columba livia)

The objective of this study was to evaluate the effects of dietary linoleic acid (LA) on growth performance, antioxidant capacity, and lipid metabolism in pigeon squabs by supplementing LA in their parental diets. A completely randomized design that consisted of a control group, 1% dietary LA addition group (LA1%), 2% dietary LA addition group (LA2%), and 4% dietary LA addition group (LA4%) was used. Six squabs from each treatment were randomly sampled at the day of hatch and days 7, 14, and 21 after hatch. The results showed that parental dietary LA had no significant influence (P > 0.05) on body weight (BW) gain or relative organ weights (% of BW) in squabs. The activities of superoxide dismutase, catalase, and glutathione peroxidase in the LA1% were significantly increased (P < 0.05) compared with those in the control group. The malondialdehyde content in the LA1% was significantly lower (P < 0.05) than that in the control group. The levels of serum triglyceride in the LA1% and LA2% were significantly decreased (P < 0.05) compared with those in the control group, whereas the serum high-density lipoprotein cholesterol level in the LA1% and LA2% and the free fatty acid level in the LA4% were significantly higher (P < 0.05) than those of the control group. The activities of lipoprotein lipase, hepatic lipase, and hormone-sensitive lipase in the LA1% were significantly higher (P < 0.05) than those in the control group. The 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in the LA1% and the hormone-sensitive lipase activity in the LA4% were significantly decreased (P < 0.05) compared with those in the control group. The mRNA expression of carnitine palmitoyltransferase 1, acyl-CoA 1, and peroxisome proliferator-activated receptor α was significantly upregulated (P < 0.05) in the LA1% compared with that in the control group. The Oil Red O staining area in the LA1% and LA2% was significantly reduced compared with that in the control group. The results indicated that although supplemental LA had negligible effects on growth and development in pigeon squabs, parental dietary LA at a concentration of 1% could have beneficial effects on maintaining squabs healthy as reflected by improved antioxidant capacity and lipid metabolism.

Effects of in ovo feeding of L-lysine on hatchability, hatching time, and early post-hatch development in domestic pigeons (Columba livia)1

This study was conducted to evaluate the effects of in ovo feeding (IOF) of L-lysine (Lys) on hatchability and development in pigeon neonates. At day 13 of incubation, fertile eggs were injected with 200 μL of sterilized saline (0.75%, SC group), 1% Conc. Lys solution (Lys group, 2.11 mg Lys dissolved in 200 μL of sterilized saline), with controls not injected (NC group). The results showed that IOF of Lys decreased the hatchability (P < 0.05) compared with other groups, whereas the hatching time was not affected among groups. On day 14 of post-hatch (D14), the body weight (BW) of squabs received Lys IOF was increased relative to the NC group (P < 0.05). Squabs in Lys group exhibited higher (P < 0.05) body weight gain (BWG) than other groups from D14 to day of hatch (DOH). Meanwhile, IOF of Lys increased the brain relative weight on DOH (P < 0.05), and organ index of heart, legs, and gizzard on day 7 of post-hatch (D7) compared with other groups. In addition, the length index of duodenum, jejunum, or ileum had no difference between groups, as well as the weight index except the weight index of duodenum in Lys group was higher than that of SC group on DOH. However, squabs received Lys IOF showed lower villus height, crypt depth, and villus surface area of jejunum than NC group (P < 0.05) on DOH, and lower crypt depth than NC and SC groups on D7. The situation was improved by D14, although there was no significant difference in morphometric trait of jejunum between Lys group and NC group, squabs received Lys IOF showed higher villus height, crypt depth, and villus surface area of jejunum than NC group. In conclusion, the present study demonstrates that IOF of Lys has negative effects on hatchability and development of early post-hatch squabs, but the situation will be improved with the growth of age.

Effects of in ovo injection of L-histidine on hatch performance and post-hatch development in domestic pigeons (Columba livia)

The objective of this study was to evaluate the effects of in ovo injection of histidine on hatch performance and post-hatch development by determining hatchability, hatching time, BW gain, carcass traits, and intestinal morphology in domestic pigeons (Columba livia). A completely randomized design (n = 3) with a L-histidine injection treatment (His group, 0.55 mg histidine dissolved in 200 μL 0.75% saline as 1% Conc compared to total histidine in the egg), a 0.75% saline injection treatment (SC group), and non-injection treatment (NC group) was used. Six squabs from each treatment were randomly sampled at day of hatch (DOH), day 7 (D7), and day 14 (D14) post hatch, respectively. Results showed that in ovo injection of histidine solution increased (P < 0.01) the hatchability in comparison with that of other groups. The hatching time of His group was earlier (P = 0.05) than that of the NC group. In ovo injection of histidine had no influence (P > 0.05) on BW gain and carcass traits, but had a significant effect on the organ index of pigeons. The index of pancreas on DOH, the indices of leg, gizzard, proventriculus, small intestine, and pancreas on D7, and the index of head on D14 were significantly increased (P < 0.05) by injection of histidine. Moreover, in ovo injection of histidine had significant effects on the weight indices of different intestinal segments and jejunal morphology in squabs. Ileum weight index on D7 from His group was significantly higher (P < 0.05) than that of other groups. Compared with the NC group, the jejunal crypt depth on DOH and D7 of His group decreased (P < 0.05), while jejunal villus area and villus crypt ratio on D7 of His group increased (P < 0.05). The results of this study indicate that in ovo injection of histidine may have beneficial effects on squabs' hatchability, intestinal development but have negligible effects on their growth performance during early post-hatch period.

Effects of in ovo injection of sulfur-containing amino acids on heat shock protein 70, corticosterone hormone, antioxidant indices, and lipid profile of newly hatched broiler chicks exposed to heat stress during incubation

This study hypothesizes that in ovo sulfur amino acids (SAA) injection can alleviate the heat or oxidative stress of hatched chicks. Thus, the study aimed to assess the impact of in ovo injection of SAA with heat stress during the incubation on heat shock protein 70 (HSP70), corticosterone hormone, antioxidant indices, and lipid profile of newly hatched broiler chicks. Eggs were incubated under optimal incubation temperature (37.8°C) from days 1 to 10 then under high temperature (39.6°C for 6 h daily) between 10 and 18 D of the incubation. At day 17.5 of incubation, 150 eggs were randomly divided into 3 groups of 50 replicate eggs. The first group served as control (non-injected group, NIG), the second group was only injected with saline solution (saline-injected group, SIG), and the third group was injected with a mixture of 5.90 mg L-methionine plus 3.40 mg L-cysteine (sulfur amino acids-injected group, SAAIG). The results exhibited that serum HSP70 and corticosterone concentrations were significantly reduced (P < 0.001) in the SAAIG compared with the NIG and SIG. In ovo SAA injection significantly augmented the antioxidant indices in the serum and tissues compared with the NIG and SIG. HSP70 mRNA relative expression was decreased but glutathione peroxidase (GSH-Px) mRNA relative expression was augmented in the tested tissues (P < 0.001) in the SAAIG compared with the NIG. The SAAIG had significantly (P < 0.05) lower levels in serum lipid profile compared to those of the control and SIG. In conclusion, in ovo SAA injection (methionine plus cysteine) in the embryonated eggs exposed to heat stress increased GSH-Px gene expression and antioxidant indices, and reduced HSP70 gene expression, corticosterone concentrations, and lipid profile of newly hatched broiler chicks.

Prolactin induces lipid synthesis of organ-cultured pigeon crops

The objective of this research was to examine the effects of prolactin (PRL) on the lipid synthesis of organ-cultured pigeon crops in vitro. In experiment 1, the histology, activities of enzymes, and expression of genes involved in metabolism and apoptosis of organ-cultured pigeon crops were analyzed over a 7-d culture period. The results showed that cultured crops maintained their structural integrity for up to 3 d in vitro. Beyond 3 d, caspase-3 activity and Bak1 gene expression increased with day of culture, whereas the activities of succinate dehydrogenase, Na+-K+-ATPase, Ca2+-Mg2+-ATPase, total ATPase, and gene expression of Bcl-2 and CK-19 diminished (P < 0.05). In experiment 2, the crops were cultured for 24, 36, and 48 h in medium containing 0, 25, or 50 ng/mL PRL, respectively, and the accumulation of lipid droplets, lipid content, and expression of fatty acid transportation- and lipogenesis-related genes were analyzed. The results showed that the crops with PRL supplements showed higher amounts of lipid droplets than those of the controls, and the droplets were mainly located in the basal nutritive layer in response to PRL. The efficacy of inducing lipid accumulation increased as the concentration of PRL increased. Crops with 50 ng/mL PRL incubated for 36 h displayed the maximal lipid content. Increasing the concentration of PRL from 0 to 50 ng/mL resulted in a dose-dependent increase in the expression of acetyl-CoA carboxylase, fatty acid synthase, fatty acid translocase, fatty acid binding protein 5, acyl-CoA binding protein, and peroxisome proliferator-activated receptor γ genes after incubation for 36 h (P < 0.05). Therefore, our results indicated that the organ-cultured pigeon crops maintained good viability for up to 3 d in vitro. Furthermore, PRL induced the lipid synthesis of organ-cultured pigeon crops in a dose- and time-dependent manner, which was related to the increased expression of genes involved in fatty acid transportation and lipogenesis.

Effects of dietary supplementation with Clostridium butyricum on laying performance, egg quality, serum parameters, and cecal microflora of laying hens in the late phase of production

This experiment was conducted to evaluate the effects of dietary supplementation with Clostridium butyricum on laying performance, egg quality, serum parameters, and cecal microflora of laying hens in the late phase of production. Jinghong-1 strain laying hens (n = 960; 48 wk of age) were randomly allocated to 5 treatment groups with 6 replicates of 32 hens. Hens were fed with basal diet (control) and basal diet supplemented with 2.5 × 104 (CB1), 5 × 104 (CB2), 1 × 105 (CB3), and 2 × 105 (CB4) cfu/g C. butyricum for 10 wk. The results showed that egg production, egg mass, and eggshell strength increased quadratically as supplemental C. butyricum increased, and these responses were maximized in the CB2 group (P < 0.05). Compared with the control group, the addition of C. butyricum resulted in quadratic effects on serum total protein, uric acid, calcium, complement component C3 and catalase concentrations, and these responses were maximized or minimized in the CB2 group (P < 0.05). Linear and quadratic increases were observed in serum IgM, total superoxide dismutase, and glutathione peroxidase concentrations, and these responses were maximized in CB2 or CB3 group (P < 0.05). The addition of C. butyricum in the CB2 group resulted in linearly increasing levels of serum IgG concentration as compared with the control group (P < 0.05). Spleen index increased (P < 0.05) in the CB2 group. Hens fed with C. butyricum reduced (P > 0.05) the population of E. coli, while Bifidobacterium counts increased quadratically and maximized in the CB2 group (P < 0.05). In conclusion, the results indicated that dietary supplementation with C. butyricum (5 × 104 or 1 × 105 cfu/g) could improve laying performance and egg quality by promoting immune function, enhancing antioxidative capacity, and benefiting the cecal microflora of laying hens in the late phase of production.

Changes in hormone profiles, growth factors, and mRNA expression of the related receptors in crop tissue, relative organ weight, and serum biochemical parameters in the domestic pigeon (Columba livia) during incubation and chick-rearing periods under artificial farming conditions

The present study was conducted to determine the changes in concentrations of hormones and growth factors and their related receptor gene expressions in crop tissue, relative organ weight, and serum biochemical parameters in male and female pigeons during incubation and chick-rearing periods under artificial farming conditions. Seventy-eight pairs of 60-week-old White King pigeons with 2 fertile eggs per pair were randomly divided into 13 groups by different breeding stages. Serum prolactin and insulin-like growth factor-1 (IGF-1) concentrations in crop tissue homogenates were the highest in both male and female pigeons at 1 d of chick-rearing (R1), while epidermal growth factor (EGF) in female pigeons peaked at d 17 of incubation (I17) (P < 0.05). mRNA expression of the prolactin and EGF receptors in the crop tissue increased at the end of incubation and the early chick-rearing stage in both sexes. However, estrogen, progesterone, and growth hormone receptor expression each decreased during the early chick-rearing stage (P < 0.05). In male pigeons, IGF-1 receptor gene expression reached its peak at R7, while in female pigeons, it increased at the end of incubation. The relative weight of breast and abdominal fat in both sexes and thighs in the males was lowest at R7, and then gradually increased to the incubation period level. Serum total protein, albumin, and globulin concentrations increased to the highest levels at I17 (P < 0.05). Total cholesterol, triglyceride, and low-density lipoprotein reached their highest values at I17 in male pigeons and R25 in female pigeons (P < 0.05). In conclusion, hormones, growth factors, and their receptors potentially underlie pigeon crop tissue development. Changes in organs and serum biochemical profiles suggested their different breeding-cycle patterns with sexual effects.

Proteomic analysis of hypothalamus and liver proteins affected by dietary l-arginine supplementation in laying hens

The goal of this study was to investigate the influence of l-arginine (l-Arg) supplementation on diet-induced changes in hypothalamus and liver proteome of laying hens. Layers were fed either an isonitrogenous control diet or a l-Arg diet. The test included a 2-week acclimation period and a 12-week experimental period. Eight layers per group were sacrificed at terminal of the experiment underwent 12 fasting. Blood and tissue samples of hypothalamus and liver were collected for further analysis. The levels of serum nitric oxide and hypothalamus neuropeptide Y of layers in l-Arg group were increased in comparison with those in control group. Quantitative proteomic analyses showed that a total of 3,715 hypothalamus proteins (235 differentially expressed) and 3797 liver proteins (373 differentially expressed) were detected between control and l-Arg-fed groups. A further enriched Gene Ontology term analysis of proteins found that 17 hypothalamus proteins (11 upregulated and six downregulated) and 29 liver proteins (14 upregulated and 15 downregulated) were altered differentially between the two groups. Our findings revealed the changes in metabolic and hormonal signals in central nervous system and peripheral tissues by responding to l-Arg feeding, which provides a possible way to gain a better understanding of l-Arg function in laying hens.

Effects of dietary Mn-methionine supplementation on the egg quality of laying hens

This study was conducted to investigate the effects of dietary manganese-methionine (Mn-Met) supplementation on the egg quality of laying hens. A total of 480 Jinghong-1 strain layers aged 53 wk were divided into 5 groups with 6 replicates of 16 layers. Birds in the control group were fed a diet supplemented with 60 mg Mn/kg in the form of MnSO4; the birds in other 4 experimental groups were fed a diet supplemented with 20, 40, 60, and 80 mg Mn/kg as Mn-Met, respectively. Dietary Mn-Met treatments significantly affected (P < 0.05) the albumen height, yolk color, and Haugh unit compared to those of the control diet. The Mn contents in the eggshell increased (P < 0.01) significantly by increasing the Mn-Met supplementation, whereas Mn content in eggshell was triple that in the yolk or albumen. Compared with the 60 mg/kg Mn-Met group, the transverse surface in the control group had (P < 0.01) a greater width of mammillary cones, and there were obvious cracks on the outer surface in the control. There was no difference (P > 0.05) in the eggshell gland (ESG) in the expression of calbindin-D28k (CaBP-D28k) mRNA in response to any diet treatment. In conclusion, dietary Mn-Met supplementation increased internal egg quality and the ultrastructure of the eggshell. Compared to the control, 60 mg/kg Mn-Met treatment resulted in improving egg quality, and 20 mg/kg Mn-Met treatment had similar effects the control treatment had on the egg quality. This indicates that the inorganic Mn can be replaced by the lower concentration of Mn-Met.

Effects of dietary L-arginine levels on small intestine protein turnover and the expression of genes related to protein synthesis and proteolysis of layers

The aim of this study was to test the effects of dietary L-arginine (Arg) levels on protein turnover in the small intestine and the expression of genes related to protein synthesis and proteolysis of laying hens. Xinyang Black commercial laying hens (n = 864, aged 217 d) were randomly distributed to 6 treatments with 4 replicates of 36 birds. The dietary treatments were corn-corn gluten meal based diets containing 0.64, 0.86, 1.03, 1.27, 1.42 and 1.66% L-Arg, respectively. Fractional protein synthesis rate (FSR) and fractional protein gain rate (FGR) in the jejunum were the highest in the 1.27% L-Arg group. The mRNA expression of target of rapamycin (TOR), ribosomal protein S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) in the duodenum reached the highest in the 1.27% L-Arg group, while the mRNA expression of 20S proteasome (20S) was the lowest in the 1.27% L-Arg group. The mRNA abundances of TOR and S6K1 in the jejunum were the highest in the 1.27% L-Arg group, while the mRNA expression of 20S was the lowest in the 1.27% L-Arg group, and the protein expression and phosphorylation levels of TOR in the 1.27% L-Arg group were higher than those in the 0.64% L-Arg group. These results indicate that the action of an appropriate level of dietary L-Arg to improve the protein synthesis of the small intestine involves up-regulating the protein expression and phosphorylation level of TOR in the jejunum accompanied by inhibiting the mRNA expression of 20S of laying hens.

Effect of mercury chloride on oxidative stress and nuclear factor erythroid 2-related factor 2 signalling molecule in liver and kidney of laying hens

This study investigated the effects of mercury chloride (HgCl₂ ) on the deposition of mercury (Hg), histopathology and oxidative stress in liver and kidney of laying hens. The gene expressions of antioxidant enzymes and nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) were further studied to uncover the molecular mechanism. A total of 960 40-week-old Hyline brown laying hens were randomly allocated to five treatments with eight pens per treatment and 24 hens per pen. The hens were fed with five experimental diets containing graded levels of Hg at 0.270, 1.250, 3.315, 9.405 and 27.230 mg/kg respectively. Results revealed that both deposition of Hg and score of injury in liver and kidney were significantly increased as dietary Hg dosage up to 27.230 mg/kg diet. Deposition of Hg was positively related to score of injury in liver and kidney of laying hens. Besides, the activities of superoxidative dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-Px), and glutathione (GSH) content all significantly decreased (p < 0.05), while malondialdehyde (MDA) content significantly increased (p < 0.05) after Hg exposure in liver and kidney of laying hens. In addition, positive relationships occurred between antioxidant enzyme activities and antioxidant enzyme gene expressions except between SOD activity and manganese superoxide dismutase (MnSOD) gene expression in liver. Meanwhile, Nrf2 gene expression was positively related to antioxidant gene expressions and negatively connected with Keap1 gene expression. Negative relationships occurred between Nrf2 and Keap1 protein levels in liver and kidney. In conclusion, Hg could dose-dependently damage liver and kidney and induced hepatic and renal oxidative stress by means of suppressing Nrf2-Keap1 signalling molecule in laying hens.

Effects of dietary threonine supplementation on intestinal barrier function and gut microbiota of laying hens

The effects of supplemental dietary threonine (Thr) on laying performance, expression of intestinal mucin 2 (MUC2) and secretory IgA (sIgA), and intestinal microbiota of laying hens fed a low CP diet were investigated. A total of 240 Lohmann Brown laying hens, 28 wk of age, was allocated to 3 dietary treatments, each of which included 5 replicates of 16 hens. Hens were fed a control diet (16% CP), a low CP diet (14% CP), or a low CP diet supplemented with 0.3% L-Thr for 12 weeks. Chemical analyses of the diets for Thr are 0.49, 0.45, and 0.69%, respectively. Lowering dietary CP impaired egg production and egg mass of laying hens. Dietary Thr supplementation to the low CP diet increased (P < 0.05) egg production and egg mass. In addition, ileal sIgA contents and MUC2 and sIgA mRNA expression were increased (P < 0.05) by dietary Thr addition. Dietary CP reduction reduced (P < 0.05) intestinal bacterial diversity, whereas dietary Thr supplementation to the low CP diet recovered the bacteria diversity and significantly increased the abundance of potential beneficial bacteria. In conclusion, dietary Thr supplementation to a low CP diet could affect intestinal health and hence productivity via regulating intestinal mucin and sIgA expression, and microbial population of laying hens.

Effects of in ovo feeding of l-arginine on hatchability, hatching time, early posthatch development, and carcass traits in domestic pigeons (Columba livia)

The objective of this research was to test the hypothesis that in ovo feeding of arginine (Arg) may improve hatchability and posthatch performance in domestic pigeons (). A completely randomized design ( = 3) with an Arg feeding treatment (Arg group, 1.14 mg Arg dissolved in 200 μL of 0.75% NaCl buffered saline as 1% concentration compared to total Arg in the egg), a buffered saline feeding treatment (SC group, 7.5 g NaCl dissolved in 1 L sterile distilled water as the concentration of poultry physiological saline), and a nonfeeding treatment (NC group) was used. Six squabs from each treatment were randomly sampled on day of hatch (DOH), posthatch d 7 (D7), and posthatch d 14 (D14), respectively. Hatchability, hatch time, BW, organ development, and carcass traits were examined. Results showed that in ovo feeding of the Arg solution increased ( < 0.05) the hatchability and advanced ( < 0.05) the hatching time in comparison with those of the other groups. Body weight of pigeon squabs that received Arg in ovo feeding was heavier ( < 0.05) on DOH and D14 than that of the NC group, and a greater ( < 0.05) BW gain from DOH to D14 and D7 to D14 was observed. Three clusters of 12 organs were classified according to the changes of organ indices. Squabs provided the Arg in ovo feeding treatment gained a priority in organ development. The heart index and gizzard index on D7 and the proventriculus index on D14 of squabs receiving Arg in ovo feeding were increased ( < 0.05) compared to those of the other groups. The brain index on DOH, the small intestine index and pancreas index on D7, and the liver index, pancreas index, and spleen index on D14 of squabs fed Arg were higher ( < 0.05) than those of the NC group. The spleen index on D7 and the small intestine index on D14 of squabs provided the Arg feeding treatment were enhanced ( < 0.05) compared with those of the SC group. The semieviscerated carcass weight of squabs receiving Arg was higher ( < 0.05) on D14 than that of other groups. The absolute weight of breast meat yield on D7 and breast meat yield percentage on D7 and D14 were improved ( < 0.05) in the Arg group compared with the NC group. The leg meat percentage on D7 and the carcass weight, eviscerated carcass weight, and absolute weight of breast meat yield on D14 were increased ( < 0.05) in the Arg group compared with those of the SC group. The results of this study indicate that in ovo feeding of pigeon embryos with Arg may have beneficial effects on squab hatch performance and early posthatch performance.

Changes in hepatic glucose and lipid metabolism-related parameters in domestic pigeon (Columba livia) during incubation and chick rearing

This study aimed to evaluate the hepatic glucose and lipid metabolism-related parameters of adult male and female White King pigeons (Columba livia) during incubation and chick rearing. At day 4 (I4), 10 (I10) and 17 (I17) of incubation and day 1 (R1), 7 (R7), 15 (R15) and 25 (R25) of chick rearing, livers were sampled from six pigeons for each sex. Glycogen and fat contents, activities of glycolytic enzymes (hexokinase, HK; 6-phosphofructokinase, 6-PFK), and genes expressions of key enzymes involved in glycolysis (pyruvate kinase, PK; glucokinase, GK), gluconeogenesis (phosphoenolpyruvate carboxykinase cytosolic, PCK1; fructose-1,6-bisphosphatase, FBP1; glucose-6-phosphatase, G6Pase), fatty acid synthesis (fatty acid synthase, FAS; acetyl-CoA carboxylase, ACC) and fatty acid β-oxidation (carnitine palmitoyltransferase 1, CPT1; acyl-CoA 1, ACO) were measured. In male and female pigeon livers, glycogen content and HK activity dramatically increased after I17 and after R1, respectively; expressions of FBP1 and G6Pase genes were maximized at R15; activity of 6-PFK and expressions of PK and CPT1 genes were highest at R7; fat content and expressions of FAS and ACC genes steeply increased from I10 to R1. In females, hepatic expressions of GK and PCK1 genes were greatest at R7 and I17, respectively; however, in males, both of them were maximized at R15. Hepatic expression of ACO gene was significantly enhanced at R1 compared to I17 and R7 in males, whereas it was notably up-regulated at I17 and R7 in females. Furthermore, expressions of PCK1, GK, FAS and ACC genes were in significant relation to fat content in the livers of female pigeons, while fat content in male pigeons was highly correlated with expression of PCK1, ACC, CPT1 and ACO genes. In conclusion, regulations of glucose and lipid metabolic processes were enhanced in parent pigeon livers from terminal phases of incubation to mid phase of chick rearing with sexual effects.

Effects of arsenic supplementation in feed on laying performance, arsenic retention of eggs and organs, biochemical indices and endocrine hormones

1. The primary objective of this experiment was to estimate the toxic effects of arsenic (As) supplementation in feed on laying performance, As retention by eggs and organs, serum biochemical indices and endocrine hormones in laying hens. 2. A total of 320 "Jinghong Number 1" hens, 56-week-old, were randomly allocated into four treatments of four replicates with 20 layers in each. Graded arsenical was added to the basal diet in the experimental diets at As levels of 0, 17, 34 and 51 mg/kg, respectively. The trial lasted for 9 weeks including 1 week for acclimatisation. 3. Supplementation of dietary As for eight weeks had no effect on laying performance. As retention in albumen, yolk, egg, liver and kidney increased as As levels increased The level of serum phosphorus (P) was minimised at the 17 mg As/kg group. The activity of serum glutamic oxaloacetic transaminase (GOT) increased linearly. No differences were observed for levels of serum calcium (Ca), alkaline phosphatase (AKP) and serum glutamic pyruvic transaminase (GPT). Concentrations of estradiol (E₂) and progesterone (PG) declined at 34 and 51 mg/kg As levels compared with the control group. As supplementation exerted no influence on levels of serum follicle stimulating hormone (FSH), luteinising hormone (LH), triiodothyronine (T₃), thyroxine (T₄) and the ratio between T₃ and T₄. 4. In conclusion, dietary As supplementation accelerated retention in tissues and eggs, and affected the laying rate by diminishing hormone levels of E2 and PG at 51 mg/kg.

Molecular cloning, characterization, and expression analysis of ghrelin and cholecystokinin in the pigeon (Columba livia)

Ghrelin and cholecystokinin (CCK) are multifunctional peptides. In the current study, complete sequences of ghrelin (800 bp) and CCK (739 bp) were firstly cloned in Columba livia by using rapid amplification of cDNA ends (RACE) method. The open reading frames of ghrelin (351bp) and CCK (393bp) encoded 116 amino acids and 130 amino acids, respectively. Sequence comparison indicated that pigeon ghrelin and CCK shared high identity with those reported in other avian species. Quantitative real-time PCR analysis found that ghrelin and CCK mRNAs expressed in three intestinal segments of pigeon during development. Both ghrelin and CCK showed generally higher expressions at days posthatch than embryonic periods regardless of intestinal segments. In duodenum and ileum, the expressions of ghrelin and CCK mRNA reached the peak values at 8 d posthatch. Jejunum CCK mRNA level increased linearly after hatching, and reached the highest point at posthatch 28 d. Based on documented effects of long chain fatty acids (LCFAs) on pigeon ghrelin and CCK expression were also investigated in vitro. Higher concentrations (50 μM or 250 μM) of linoleic acid, α-linolenic acid or arachidonic acid can significantly increase ghrelin mRNA level in pigeon jejunum. However, for oleic acid, the induction of ghrelin gene expressions needed a lower concentration (5 μM). 5 μM of linoleic acid, α-linolenic acid or arachidonic acid and 250 μM palmitic acid repressed CCK expression significantly. A higher concentration (250 μM) of oleic acid or α-linolenic acid can up-regulate CCK mRNA level significantly. Our results indicated that ghrelin and CCK may act key functions in pigeon intestine development and their expressions could be regulated by LCFAs.

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low-crude-protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L-Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57-0.66%. In addition, serum-free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low-CP diet compared with hens fed CP (16.18%) and hens fed 0.57-0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF-γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL-2, IL-6, IL-1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low-crude-protein diet of laying hens during the peak production period.

L-arginine upregulates the gene expression of target of rapamycin signaling pathway and stimulates protein synthesis in chicken intestinal epithelial cells

L-arginine (Arg) is an indispensable amino acid in avians and is required for growth. The aim of this study was to investigate the effects of L-Arg on protein synthesis and genes expression involved in target of rapamycin (TOR) signaling pathway in chicken enterocytes. Cells were cultured for 4 days in L-Arg-free Dulbecco's modified Eagle's medium containing 10, 100, 200, 400, or 600 μM L-Arg. Cell growth, cell cycle, protein synthesis, and protein degradation as well as mRNA expression levels of TOR, ribosomal protein S6 kinase 1 (S6K1), and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) were determined. The results showed that cell viability was enhanced by L-Arg with a maximal response at 10 to 400 μM. Increasing extracellular concentrations of L-Arg from 10 to 400 μM increased the cells in S and G2/M phase to a significant extent and decreased cell numbers in G0/G1 phase. Further more, addition of 100, 200, or 400 μM L-Arg to culture medium increased protein synthesis and reduced protein degradation in chicken intestinal epithelial cells. Consistent with the data on cell growth and protein turnover, supplementation of 100, 200, or 400 μM L-Arg increased the mRNA abundances of TOR, 4E-BP1, and S6K1. It was concluded the action of L-Arg involves in upregulating the genes expression of TOR cell signaling pathway which increases protein synthesis and reduces protein degradation.

Effect of excess dietary L-valine on laying hen performance, egg quality, serum free amino acids, immune function and antioxidant enzyme activity

1. The aim of this study was to evaluate the tolerance of laying hens for an excessive L-valine (L-val) supply on laying performance, egg quality, serum free amino acids, immune function and antioxidant enzyme activities of laying hens. 2. A total of 720 HyLine Brown hens were allocated to 5 dietary treatment groups, each of which included 6 replicates of 24 hens, from 40 to 47 weeks of age. Graded amounts of L-val were added to the basal diet to achieve concentrations of 0 (control), 1, 2, 3 and 4 g/kg, respectively, in the experimental diets. 3. Supplementing the diet with L-val did not affect egg production, egg mass, egg weight, feed conversion ratio (FCR) or egg quality. The average daily feed intake response to supplemental L-val was quadratic and was maximised at 2.0 g L-val/kg diet. No differences were observed for total protein, total amino acids, blood urea nitrogen (BUN), uric acid, lactate dehydrogenase (LDH), alkaline phosphatase (AKP), Ca and P concentrations among the treatments. 4. Serum albumin concentration increased significantly in response to supplemental L-val and was also maximised at 2.0 g/kg. In addition, serum glucose increased quadratically to peak at 2.0 g L-val/kg diet. Serum free valine increased as L-val concentration increased to 2.0 g/kg diet and then decreased linearly. 5. Supplementation of L-val did not affect the serum concentrations of total antioxidative capability (T-AOC), superoxide dismutase (SOD) and malondialdehyde (MDA). L-val supplementation did not affect the concentrations of immunoglobulins IgG, IgA, IgM and complements (C3 and C4). Serum concentration of triiodothyronine (T3) increased significantly at 2.0 g L-val/kg diet. 6. It is concluded that high concentrations of L-val are tolerated and can be successfully supplemented into diets without detrimental effects on laying performance or immune function of laying hens.

Effect of a probiotic mixture on intestinal microflora, morphology, and barrier integrity of broilers subjected to heat stress

The current study investigated the efficacy of a probiotic mixture on ameliorating heat stress-induced impairment of intestinal microflora, morphology, and barrier integrity in broilers. The probiotic mixture contained Bacillus licheniformis, Bacillus subtilis, and Lactobacillus plantarum. Three hundred sixty 21-d-old Ross 308 male broilers were allocated in 4 experimental treatments, each of which was replicated 6 times with 15 broilers per replicate. A 2 × 2 factorial design was used in the study, and the main factors were composed of diet (basal diet or addition of 1.5 g/kg of probiotic mixture) and temperature (thermoneutral zone or heat stress). From d 22 to 42, birds were either raised in a thermoneutral zone (22°C) or subjected to cyclic heat stress by exposing them to 33°C for 10 h (from 0800 to 1800) and 22°C from 1800 to 0800. Compared with birds kept in the thermoneutral zone, birds subjected to heat stress had reduced ADG and ADFI; lower viable counts of Lactobacillus and Bifidobacterium and increased viable counts of coliforms and Clostridium in small intestinal contents; shorter jejunal villus height, deeper crypt depth, and lower ratio of villus height to crypt depth; decreased jejunal transepithelial electrical resistance and a higher level of jejunal paracellular permeability of fluorescein isothiocyanate dextran 4 kDa; and downregulated protein levels of occludin and zonula occludens-1 (P < 0.05). Supplemental probiotics increased (P < 0.05) small intestinal Lactobacillus and Bifidobacterium, jejunal villus height, protein level of occludin, and decreased (P < 0.05) feed to gain ratio and small intestinal coliforms. These results indicate that dietary addition of probiotic mixture was effective in partially ameliorating intestinal barrier function. But no temperature × diet interaction was observed in the present study, revealing that the supplemented probiotics had the same effect at both temperatures.

Influence of L-threonine supplementation on goblet cell numbers, histological structure and antioxidant enzyme activities of laying hens reared in a hot and humid climate

1. A previous experiment in our laboratory found that L-threonine supplementation at 0.2 and 0.3% increased egg production and the concentration of serum IgG, respectively. The objective of this current trial was to determine if both supplementation levels can positively influence histological structure, goblet cell numbers, or antioxidant enzyme activities. 2. Babcock Brown layers (n=576), 40 weeks of age, were allocated to three treatment groups, each of which included 6 replicates of 32 hens. Each group received the same basal diet formulated with maize, peanut meal and crystalline amino acids. L-threonine was added to the basal diet at 0 (control), 0.2, and 0.3%, respectively for 8 weeks. Chemical analysis of the diets for threonine values were 0.47, 0.66 and 0.74 %, respectively. 3. The numbers of goblet cells did not change due to L-threonine supplementation. Also, L-threonine had no affect on the villus height and mucosal thickness. No differences were found due to treatments among groups in the activity of alkaline phosphatase (ALP) in jejunum or ileum. L-threonine supplementation at 0.2% maximised the concentration of superoxide dismutases (SOD) in both serum and liver. 4. In conclusion, L-threonine supplementation had no affect on gut morphology but may have an antioxidant function at 0.2%.

Posthatch development of intestinal morphology and digestive enzyme activities in domestic pigeons (Columba livia)

The gastrointestinal tract plays an important role in studies of avian ontogenies because of its key function in nutrient intake. The pattern of intestinal development during postnatal growth in domestic pigeons (Columba livia), as an altricial bird, would be different from the pattern observed in precocial poultry. In this study, the intestinal morphology, mucosal enzyme activities, and pancreatic enzyme activities were determined from hatch to 14 d of age in pigeons. Rapid morphological development was observed immediately after hatching. Villus area and crypt depth increased in parallel in the duodenum and jejunum and more slowly in the ileum. Mucosal enzyme activities per gram of duodenum, jejunum, and ileum varied significantly with segment and age. There were also intestinal segment × age interactions, in which enzyme activity increased most dramatically in the jejunum as compared with the duodenum and ileum for sucrase and maltase activity from day of hatch to 8 d, and for alkaline phosphatase activity through 14 d. However, aminopeptidase-N activity increased most dramatically from day of hatch to 3 d in the ileum as compared with the duodenum and jejunum. Changes in carbohydrate-digesting enzymes activity in duodenum, jejunum, ileum, and pancreas are more pronounced than for protein-digesting enzymes activity from 3 d after hatching. Intestinal total enzyme activities exhibited a steady increase, which was highly correlated with BW. Pancreatic enzymes indicated patterns somewhat similar to those for intestinal enzymes. It was concluded that development of the absorptive area and the capacity for hydrolysis in the duodenum, jejunum, and ileum was rapid immediately after hatching, although rates of development were different in the 3 segments. Young pigeons differ from poultry, in whom intestinal and pancreatic digestive enzyme activities per gram of tissue are generally constant or decline during postnatal development. Also, the data seem consistent with the idea that intestinal hydrolysis may be a determining step in digestion and hence growth.

Molecular cloning, characterization, and expression analysis of fatty acid translocase (FAT/CD36) in the pigeon (Columba livia domestica)

Fatty acid translocase (FAT/CD36) is a transmembrane glycoprotein that plays an important role in transporting long-chain fatty acids. In the current study, a full-length cDNA of FAT/CD36 was first cloned from the intestine of White King pigeon by rapid amplification of cDNA ends (RACE) method. The full-length cDNA of pigeon FAT/CD36 was 2,282 bp, including a 5'-untranslated region of 224 bp, a 3'-untranslated region of 642 bp, and an open reading frame of 1,416 bp encoding a protein of 471 amino acids with the predicted molecular weight of 52.7 kDa. Sequence comparison indicated that FAT/CD36 of pigeon had high identity with other avian FAT/CD36. Using quantitative real-time PCR, expression of FAT/CD36 was the greatest in the duodenum at 28 d posthatch, and in the jejunum, the expression of FAT/CD36 at 14 d posthatch was greater than at 8 d but the same as 28 d posthatch. However, in the ileum, expression of FAT/CD36 peaked at embryonic d 15 and 8 d posthatch. The effects of long-chain fatty acids on pigeon FAT/CD36 and peroxisome proliferator activated receptor γ (PPARγ) mRNA expression were also investigated in vitro. It showed that a low concentration (5 μM) of oleic acid, palmitic acid, and linoleic acid can significantly increase FAT/CD36 and PPARγ mRNA level in pigeon jejunum. However, for linolenic acid or arachidonic acid, the induction of both gene expressions needed a higher concentration (50 μM or 250 μM). Two hundred and 50 μM palmitic acid was shown to suppress FAT/CD36 gene expression. The results suggest that FAT/CD36 may be a representative of intestine development in pigeon, and it could be regulated by long-chain fatty acids via PPARγ pathway.

Effect of β-Mannanase (Hemicell) on Growth Performance and Immunity of Broilers

Two hundred four broilers (1-d-old) were randomly allocated to 4 treatments, each of which had 3 pens of 17 chicks per pen and were used to investigate the effects of beta-mannanase (Hemicell) on growth performance and immunity. The chicks received the same basal diet based on corn-soybean meal and Hemicell was added to the basal diet at 0, 0.025, 0.05, and 0.075%, respectively. Weight of each replicate was determined at wk 0, 3, and 6 of age. There were no significant differences in average feed intake in the 0- to 3-wk and 0- to 6-wk periods, and no differences in serum IgA, or IgG concentrations. However, the addition of Hemicell significantly increased (P < 0.05) weight gain in the 4- to 6-wk and 0- to 6-wk periods. Feed conversion for the 0.025 and 0.05% groups was significantly greater (P < 0.05) than for the control group in the 4- to 6-wk and 0- to 6-wk periods. Hemicell significantly increased (P < 0.05) the serum IgM concentration in 3- and 6-wk-old broilers. Proliferation of T lymphocytes in 6-wk-old broilers for the 0.05% group was also improved (P < 0.05) significantly. The results indicate that Hemicell may improve growth performance and immunity of broilers.