Influence of different types of sugar on overfeeding performance-part of meat quality.

Previous research in our lab showed that 10% glucose, 10% fructose, and 10% sucrose can induce lipid deposition in goose fatty liver formation process more efficiently. However, whether the overfeeding diet supplement with sugar can affect the meat quality is unclear. The aim of this research was to estimate the meat quality of geese overfed with overfeeding diet adding with different types of sugar. The results indicated there were no significant differences in the diameter of muscle fiber, the muscle fiber density, pH0, pH24, the meat color, the cooking loss, the drip loss, the shear force and the dry matter in breast muscle and thigh muscle between corn flour groups and three sugars groups (P > 0.05). The crude fat content of breast muscle in fructose group was significantly higher than that in sucrose group (P < 0.05); the inosinic acid content of leg muscle in fructose group was significantly higher than that in the sucrose group (P < 0.05); the ratios of essential amino acids to total amino acids (EAA/TAA) in the breast muscle of maize flour group, fructose group, sucrose group and glucose group were 42%, 35%, 32% or 34%;57%, 64%, 64%, and 62%, respectively; the ratios of essential amino acids to total amino acids in leg muscle of maize flour group, fructose group, sucrose group and glucose group were 31%, 33%, 35%, and 34%, respectively. The contents of C16:1 and C18:1 n-9c in breast muscle in fructose group were significantly higher than that in sucrose group (P < 0.05). Compared with maize flour group, the contents of C18:0 and C20:0 were lower in leg muscle of sugar group (P < 0.05). Compared with the maize flour group, the activities of hydrogen peroxide (H2O2) and glutathione peroxidase (GSH-PX) in breast muscle were higher than those of sucrose group (P < 0.05), the total antioxidant capacity (T-AOC) levels in breast muscle was higher than that of fructose group and sucrose group (P < 0.05). Cluster analysis and principal component analysis (PCA) showed that there was no difference in meat quality between maize flour and sugar group. In conclusion, the overfeeding with maize flour supplement with 10% sugar had no evident influence on the meat quality.

Reference gene selection for expression studies in the reproductive axis tissues of Magang geese at different reproductive stages under light treatment.

In quantitative PCR research, appropriate reference genes are key to determining accurate mRNA expression levels. In order to screen the reference genes suitable for detecting gene expression in tissues of the reproductive axis, a total of 420 (males and females = 1:5) 3-year-old Magang geese were selected and subjected to light treatment. The hypothalamus, pituitary and testicular tissues were subsequently collected at different stages. Ten genes including HPRT1, GAPDH, ACTB, LDHA, SDHA, B2M, TUBB4, TFRC, RPS2 and RPL4 were selected as candidate reference genes. The expression of these genes in goose reproductive axis tissues was detected by real-time fluorescent quantitative PCR. The ΔCT, geNorm, NormFinder and BestKeeper algorithms were applied to sort gene expression according to stability. The results showed that ACTB and TUBB4 were the most suitable reference genes for the hypothalamic tissue of Magang goose in the three breeding stages; HPRT1 and RPL4 for pituitary tissue; and HPRT1 and LDHA for testicular tissue. For all three reproductive axis tissues, ACTB was the most suitable reference gene, whereas the least stable reference gene was GAPDH. Altogether, these results can provide references for tissue expression studies in geese under light treatment.

Dietary combined supplementation of iron and Bacillus subtilis enhances reproductive performance, eggshell quality, nutrient digestibility, antioxidant capacity, and hematopoietic function in breeder geese.

A 3 × 2 factorial arrangement of treatments was conducted to investigate the effects of iron (Fe, 40, 60, and 80 mg/kg) and Bacillus subtilis (2.5 × 109 and 5.0 × 109 CFU/kg) supplementation on reproductive performance, egg quality, nutrient digestibility, hormone levels, antioxidant indices, and hematological parameters in breeder geese. A total of one hundredtwenty 46-week-old Wulong breeder geese were randomly assigned to 1 of 6 dietary treatments with 4 replicates per treatment and 5 geese per replicate for 10 wk following 1 wk of adaption. Dietary Fe supplementation increased egg weight (P = 0.036), fertility (P = 0.022), serum total antioxidant capacity (P = 0.022), red blood cell (P = 0.001), hematocrit (HCT, P < 0.001), hemoglobin (HGB, P = 0.005), and mean corpuscular volume (MCV, P < 0.001). Dietary B. subtilis supplementation increased egg production (P = 0.025), eggshell thickness (P = 0.020), apparent phosphorus digestibility (P < 0.001), serum follicle stimulating hormone (P = 0.043), total antioxidant capacity (P < 0.001), HCT (P < 0.001), HGB (P < 0.001), and MCV (P = 0.025), and reduced malondialdehyde level (P = 0.008). The birds fed diets supplemented with 60 mg/kg Fe and 5 × 109 CFU/kg B. subtilis showed the highest percentage of hatched eggs (P = 0.004) and mean corpuscular hemoglobin (P < 0.001) among the 6 groups. Supplementation of 40 and 60 mg/kg Fe significantly increased the apparent digestibility of calcium compared with that of 80 mg/kg Fe in the birds fed 5.0 × 109 CFU/kg B. subtilis (P = 0.004). Supplementation with 60 and 80 mg/kg Fe in the birds fed 5 × 109 CFU/kg B. subtilis significantly decreased serum urea nitrogen level compared with other 4 groups (P = 0.022). In conclusion, the combination of Fe and B. subtilis effectively improves reproductive performance, eggshell quality, nutrient digestibility, antioxidant status, and hematopoietic function of breeder geese. Dietary addition of 60 mg/kg Fe and 5.0 × 109 CFU/kg B. subtilis was an optimum supplementation dose.

Effects of dietary supplementation of chitosan on carcass composition and meat quality in growing Huoyan geese.

This present study was conducted to investigate the effects of dietary supplementation of chitosan (CS) on carcass composition and meat quality in growing Huoyan geese. A total of 320 (28-day-old) growing Huoyan geese (sex balance) with similar body weight were randomly divided into the following 4 main groups: basal diet (control), basal diet + 100 mg/kg CS (CS100), basal diet + 200 mg/kg CS (CS200), and basal diet + 400 mg/kg CS (CS400) groups. Each group includes 4 replicates with 20 geese per replicate, and the feeding trail lasted for 4 wk. The results showed that the geese in CS200 group had lower abdominal fat percentage, b∗ value, shear force, crude fat content, and drip loss of breast and thigh muscle than those in the control group (P < 0.05). In addition, the CS200 group had higher glutamic acid, glycine, lysine, valine, total nonessential amino acids, total essential amino acids, total amino acids, C22:0, C16:1, C18:1, C20:1, C20:2, C20:5, total monounsaturated fatty acids concentration and polyunsaturated fatty acids (PUFA), and saturated fatty acids (SFA) ratio and lower total SFA, total PUFA concentration, and total n-6:n-3 ratio in breast muscle than the control group (P < 0.05). Taken together, these results indicated that addition of 200 mg/kg CS improved meat quality in growing Huoyan geese through altering slaughter performance, meat traits, amino acids, and fatty acids composition.

Research Note: Effect of diet with different proportions of ryegrass on breast meat quality of broiler geese.

This study was conducted to determine the effects of diet with different proportions of ryegrass on breast meat quality of geese. In total, 240 healthy male Yangzhou geese (28-day-old) with similar body weight were divided randomly into 4 diet groups (control group: fed commercial diets; treatment groups I, II, and III: fed ryegrass and commercial diet in the ratios of 1.5:1, 2:1, and 3:1, respectively), the birds being fed from the age of 29 to 70 D. The results shows that the body weights of 70-day-old geese of treatment groups II and III were lower than those in the control group, whereas those of geese of treatment group I were similar to those of the control group. The contents of flavor amino acid and total (essential) amino acids in treatment groups I and II were higher than those in treatment group III (P < 0.05). In addition, grass supplementation reduced saturated fatty acid content and increased that of omega-3 (n-3) polyunsaturated fatty acids, relative to the control group (P < 0.05). Finally, among the 6 minerals analyzed in breast muscle, differences existed in Zn, Se, and Cu contents among the geese fed with different proportions of ryegrass. Zn content of geese from treatment groups II and III was significantly higher than that of those of the control group; Cu content was lower with grass intake and was significantly higher in the control group than in treatment group III; Se content was significantly higher in the control group than in both groups II and III (all at P < 0.05). The results from this study indicated that geese fed with low proportions of ryegrass (1.5:1 or 2:1) showed good growth performance and increased total (essential) amino acid, flavor amino acid, n-3 polyunsaturated fatty acid, and Zn content in meat, which had a certain guiding value for the production of high-quality goose meat under intensive feeding conditions.

Effects of cassava foliage on feed digestion, meat quality, and antioxidative status of geese.

As the by-product of cassava, cassava foliage (CF) has been widely used in livestock feed. However, little information is available on its utilization for geese. In this study, we aimed to investigate the effects of CF on the feed digestion, meat quality, and antioxidative status of geese. A total of 108 male Hainan indigenous geese (28-days-old) with similar body weight were randomly and evenly divided into 3 groups, and the geese were fed for 42 D on either the control diet (CON) consisting of ground maize, soybean meal, and wheat bran, or the experimental diet composed of ground maize, soybean meal, and wheat bran supplemented with 5% (CF1) or 10% (CF2) CF. Dietary nutrient digestibility, physicochemical properties, amino acid and fatty acid composition of meat, and antioxidative status of geese were evaluated. The results showed that supplementation of CF in goose diets enhanced the feed digestion and affected the meat quality. In addition, supplementation of CF had beneficial effects on the regulation of amino acid and fatty acid profiles in muscle tissues. Moreover, such supplementation had no significant effect on antioxidative status. Taken together, goose diet containing 5% CF was recommended based on feed efficiency and meat quality.

Effects of dietary Enteromorpha powder supplementation on productive performance, egg quality, and antioxidant performance during the late laying period in Zi geese.

This study investigated the effects of dietary Enteromorpha powder supplementation on the productive performance, egg quality, and antioxidant performance of Zi geese during the late laying period. Three hundred twelve Zi geese (1 yr old) were randomly allocated into 2 cohorts to form a control group and an experimental group (with each cohort including 6 replicates and 21 female geese and 5 male geese in each replicate). The control group was fed a basal diet, and the experimental group was fed a diet containing 3% Enteromorpha powder. The data showed that Enteromorpha powder supplementation significantly improved egg production, laying rate, average daily egg weight (P < 0.01), and egg yolk color (P < 0.05). Supplementation decreased the ADFI and feed conversion rate (P < 0.01). Compared with the control group, glutathione peroxidase (GSH-Px) activity was significantly higher in serum and ovary tissue (P < 0.05), but GSH-Px activity was lower in liver tissue (P < 0.01). Malondialdehyde was reduced in liver and ovary tissue (P < 0.05) in the Enteromorpha powder supplementation group. Meanwhile, the expression of the CAT gene was significantly upregulated in the liver (P < 0.01) in the Enteromorpha group. These results indicate that dietary Enteromorpha powder supplementation improved productive performance and reduced the level of lipid peroxidation in Zi geese during the late laying period.

Effect of cassava foliage on the performance, carcass characteristics and gastrointestinal tract development of geese.

Cassava foliage is a by-product of cassava and has been widely used in animal feed. However, little information is available on its utilization for geese. In this study, we investigated the effects of cassava foliage on the performance, carcass characteristics, and gastrointestinal tract development of geese. A total of 108 28-day-old Hainan indigenous male geese with similar body weight were randomly divided into 3 groups with 6 pens of 6 geese per group and fed for 42 D on either the control diet of ground maize, soybean meal, and wheat bran or the experimental diet of ground maize, soybean meal, and wheat bran supplemented with 5% or 10% cassava foliage, respectively. On day 70, their body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), carcass characteristics, and gastrointestinal tract development were compared. The results showed that cassava foliage diet significantly improved goose's BW (P < 0.05), ADG (P < 0.05), and ADFI (P < 0.05), affected carcass characteristics such as relative meat content (P < 0.05) and abdominal fat content (P < 0.05), and facilitated goose's gastrointestinal tract development. These findings suggested that incorporating cassava foliage into the diet of geese (day 28-70) could have positive effects, and supplementing 5% cassava foliage was more beneficial than 10%.

Effects of cottonseed meal on growth performance, small intestinal morphology, digestive enzyme activities, and serum biochemical parameters of geese.

Cottonseed meal (CSM), an oil industry by-product, is an attractive alternative protein source in poultry diets. To investigate the effects of CSM on growth performance, small intestinal morphology, digestive enzyme activities, and serum biochemical parameters of geese, a total of 300 healthy, 28-day-old, male Jiangnan geese were randomly divided into 5 treatments, with 6 pens of 10 geese each. Five isonitrogenous and isocaloric experimental diets were formulated to produce diets in which 0% (control), 25% (CSM25), 50% (CSM50), 75% (CSM75), and 100% (CSM100) of protein from soybean meal was replaced by CSM (corresponding to 0, 6.73, 13.46, 20.18, and 26.91% CSM in the feed, respectively). At 28, 42, and 70 d, BW and feed intake for each pen were measured. Blood, small intestine, and chyme samples were collected at 70 d. The results showed that dietary 13.46% CSM or more decreased BW at 42 d and ADG from 28 to 42 d but increased the feed/gain ratio (F/G) from 28 to 42 d (P < 0.05). From 42 to 70 d, geese in the CSM groups had higher ADFI and ADG than those of the control group (P < 0.05). Geese in the CSM75 and CSM100 groups had a higher ADG from 28 to 70 d and BW at 70 d and a lower F/G from 42 to 70 d than those of the control group (P < 0.05). Dietary 6.73% CSM also improved ADFI from 28 to 70 d (P < 0.05). Compared to the control, geese in the CSM groups had decreased pepsin and lipase activities, and those in the CSM25, CSM50, and CSM75 groups had increased villus height in the jejunum at 70 d (P < 0.05). All groups had similar concentrations of total protein, blood urea nitrogen, uric acid, cholesterol, triglyceride, calcium, and phosphorus in serum (P > 0.05). In conclusion, excessive use of CSM (>6.73%) decreased growth performance at an early age (28 to 42 d) in geese, whereas 6.73 to 26.91% CSM in feed improved growth performance from 28 to 70 d.

Comparative proteomic analysis of hypothalamus tissue from Huoyan geese between pre-laying period and laying period using an iTRAQ-based approach.

The hypothalamus plays a central role in controlling poultry endocrine and reproductive activities. So far there is limited information focused on the proteome profiles of the hypothalamus from geese during different stages of the egg-laying cycle. In order to identify proteins regulating the egg-laying process of Huoyan geese, we investigated the proteome profiles of the hypothalamus from Huoyan geese during the laying period and pre-laying period by applying an isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic technology. A total number of 3,337 were identified and quantified, of which 18 were significantly up-regulated and 16 were significantly down-regulated. These differentially expressed proteins were subjected to bioinformatics analyses based on the Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway. Some of these were revealed to be involved in hormone and neurotransmitter secretion, exocytosis, calcium ion transport and synaptic transmission. Subsequently, excitatory amino acid transporter 2, complexin-1 and inositol 1,4,5-trisphosphate receptor, type 3 were confirmed at the messenger RNA level using quantitative real-time RT-PCR. Then, the abundance change of these proteins was verified further using Western blotting analysis. These data may aid in elucidating the molecular mechanism of higher laying performance in Huoyan geese.

Influence of the incorporation mode of sugar beet pulp in the finishing diet on the digestive tract and performances of geese reared for foie gras production.

The aim of this work was to study the effects of incorporating sugar beet pulp (SBP) into the diet of geese in two feeding systems (complete pelleted feed or loose-mix feeding system) on crop development and performance. A total of 480 1-d-old male geese were divided into three groups whose diet differed from d 56 to 90: a complete pelleted diet containing 50% corn (control diet: AMEn 11.5 MJ/kg; CP 161 g/kg), and no SBP; a complete pelleted diet containing 50% corn and 10% SBP (SBPcp diet: AMEn: 11.5 MJ/kg; CP: 161 g/kg); and a mix in the same feeder (SBPlm diet) of 500 g/kg of protein-rich pellets containing 20% SBP (SBPprp: AMEn: 9.0 MJ/kg; CP: 250 g/kg) and 500 g/kg of whole corn (WC: AMEn: 14.0 MJ/kg; CP: 72 g/kg). Body traits, including crop volume, were measured at d 91. From d 91 to 106, 88 birds/group were overfed with a mixture containing mainly corn and water before slaughter to measure fatty liver performance. Feed intake from d 56 to 90 was higher (+10%; P = 0.004) in the SBPcp group than the other two, but at d 90, the body weight (BW) of the birds was higher (+7%; P = 0.002) in the SBPlm group than the other two. At d 91, the volume of the crop was greater in the SBPcp group (80.4 mL/kg of BW, P < 0.001) than in the control group (60.3 mL/kg of BW), the SBPlm group being intermediate (64.1 mL/kg of BW). Feed intake (13,321 g), weight gain (2,733 g), and feed-to-gain ratio (4.9) during the overfeeding period, as well as fatty liver weight (963 g) and commercial grading, were similar (P > 0.05) between the three groups. In conclusion, the use of sugar beet pulp in the diet of finishing geese helps the adaptation of the digestive tract to the overfeeding period, even in a loose-mix feeding system based on whole corn.

Response of growing goslings to dietary supplementation with methionine and betaine.

An experiment with a 2 × 3 factorial design with two concentrations of dietary betaine (0 and 600 mg/kg) and three dietary concentrations of methionine (0, 600 and 1200 mg/kg) was conducted using goslings to estimate growth, nutrient utilisation and digestibility of amino acids from 21 to 70 d of age. Three hundred geese were randomised at 18 d of age into 6 groups with 5 replicates per treatment and 10 geese per replicate. Increasing dietary concentrations of methionine gave a linear increase in body weight and average daily gain. The coefficient of crude fat retention increased as dietary methionine increased and there was a significant non-linear response to increasing dietary methionine. Similarly, increasing supplemental methionine gave linear increases in the digestibility of methionine and cysteine. The results of this study indicated that optimal dietary supplementation of methionine could increase growth performance and methionine and cysteine utilisation in growing goslings. Betaine supplementation had no apparent sparing effect on methionine needs for growth performance, but did improve the apparent cysteine digestibility.

Molecular cloning and expression analysis of neuregulin 1 (Nrg1) in the hypothalamus of Huoyan goose during different stages of the egg-laying cycle.

Neuregulin 1 (Nrg1) is one of the most active members of the epidermal growth factor (EGF)-like family, which bind to the ErbB tyrosine kinase receptor and play many roles in modulation of synaptic activity, synaptogenesis, GABAergic neurotransmission, neurotransmitter receptor expression and the hormonal control of neuroendocrine reproductive development. In this study, we cloned and characterized the cDNA of goose Nrg1 originating from hypothalamus tissues of Huoyan goose using RACE method, investigated the mRNA expression profiles during different stages of the egg-laying cycle by real-time PCR. Multiple alignments and phylogenetic analyses of the deduced amino acid sequence were conducted using bioinformatics tools. We also determined the profiles of blood serum progesterone, estradiol, FSH and LH content during different egg-laying stages using radioimmunoassay. The cDNA of Nrg1 is consisted of 2061bp open reading frame encoding 686 amino acids. The deduced amino acid sequence of goose Nrg1 contains one EGF domain from amino acid residues 224 to 265 and shows a closer genetic relationship to the avian species than to other mammal species. The expression level of Nrg1 mRNA increased from the pre-laying period to the peak-laying period, reached its peak in the peak-laying period, and then decreased in the ceased period. The concentrations of FSH and estradiol in blood serum have the similar changing trend. These results might suggest a potential correlation between Nrg1/ErbB signaling network with the reproductive neuroendocrine of Huoyan goose.

Effects of dietary garlic scape meal on the growth and meat characteristics of geese.

This study evaluated the growth performance and meat characteristics of grower geese whose diets included garlic scape meal (GSM), a by-product of garlic production. Scape is the leaf-less flower stem of garlic. Garlic scape (GS) extracts contained 84.7 ± 3.8 µg/g dry weight (DW), 81.4 ± 8.2 µg/g DW, 0.78 ± 0.05 mg gallic acid equivalent/g DW and 31.67 ± 2.25 µg/g DW of allicin, alliin, total phenolics and flavonoid contents, respectively. In total, 120 White Roman geese aged 5 weeks were randomly distributed among 12 pens and fed on a grower diet ad libitum during the growth period. Employing a completely random design, 5 males and 5 females were placed in each pen. Each treatment was applied to three pens (in total 30 birds) and the treatments comprised the following: 1) control (maize-soybean meal), 2) 5% of maize replaced with 5% of GSM (5% GSM), 3) 10% of maize replaced with 10% of GSM (10% GSM) and 4) 15% of maize replaced with 15% of GSM (15% GSM). Each group of 30 birds was treated for 8 weeks. The results revealed that the 15% GSM group was characterised by a lower feed conversion ratio than the control group; however, these groups did not differ significantly in their body weights (BWs). In addition, the 10% GSM group did not differ in both the feed conversion ratio and consumption. The flavour intensity score of meats in the 10% GSM group was significantly lower than those of meats in the 5% GSM and control groups. The general acceptability scores of meats in the 5% GSM and control groups were higher than those of meat in the 10% GSM group. The study concluded that 5% dietary GSM in the feed did not adversely affect the growth performance, meat characteristics or sensory evaluation of grower geese. Hence, the environment can be protected by including agricultural waste in goose diets.

Effect of flaxseed on the fatty acid profile of egg yolk and antioxidant status of their neonatal offspring in Huoyan geese.

The aim of this study was to evaluate the effects of geese's maternal diet supplemented with flaxseed on the fatty acid profiles of egg yolks and the antioxidant status of their offspring. A total of 288 female Huoyan geese (42 weeks old) were randomly allotted to four experimental groups in this 56-day experiment and fed on diets containing flaxseed at 0% (control), 5%, 10% and 15%, respectively. There were nine replicate pens per treatment, with eight geese per replicate pen. The concentration of α-linolenic acid (linear, P<0.01), EPA (20:5n-3; linear, P<0.01), DHA (22:6n-3; quadratic, P=0.03) and n-3 polyunsaturated fatty acid (PUFA) (linear, P<0.01) levels in the yolk lipids increased with increasing dietary flaxseed levels. Yolk palmitic acid (16:0, linear, P=0.05), saturated fatty acid (linear, P=0.04) level and total n-6/n-3 ratio (P<0.01) decreased in a linear fashion as dietary flaxseed levels increased. Increasing dietary flaxseed levels linearly decreased (P=0.01) the total cholesterol in egg yolks. After hatching, three 1-day-old gosling were selected randomly from each replicate to determine blood characteristics and liver antioxidant status. Aspartate aminotransferase activity (linear, P=0.03), total triglycerides (linear, P=0.02) and total cholesterol (linear, P=0.05) contents in blood linearly decreased as the levels of flaxseed increased. A linear dose response to maternal dietary flaxseed was detected for the activities of the goslings' liver enzymes catalase (linear, P=0.01), superoxide dismutase (linear, P<0.01) and glutathione peroxidase (linear, P<0.01). The malondialdehyde (quadratic, P=0.03) and alkaline phosphatase content in the livers of goslings decreased as flaxseed supplementation levels increased. In conclusion, the dietary addition of flaxseed up to 15%, in the maternal diet resulted in increased n-3 PUFA levels in egg yolks and improved the antioxidant status of offspring in a dose-dependent manner.

Transcriptome profiling of the hypothalamus during prelaying and laying periods in Sichuan white geese (Anser cygnoides).

The Sichuan White goose is a Chinese breed well known for the quality of its meat. However, reproductive performance in this goose is not ideal, and little information is available regarding the abundance of transcripts. To better understand the molecular mechanism(s) underpinning prelaying and laying periods in the Sichuan white goose, high-throughput RNA sequencing was performed to analyze the transcriptome in the hypothalamus. After sequencing and annotation, 26,921 unigenes were obtained, with 48 transcripts up-regulated in the prelaying period and 180 transcripts up-regulated during the laying period. These transcripts were primarily related to diseases, cancers, signaling molecules and interactions, the nervous system and the immune system. Eight transcripts were selected for further analyses with quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The qRT-PCR results were mostly consistent with those from the high-throughput RNA sequencing. Among these transcripts, serine/threonine-protein kinase (AMPK), heat shock protein 70 (HSP70) and NADH dehydrogenase 1 (ND1) were differentially expressed during the prelaying and laying periods. The results of this study provide a useful resource for future studies examining the hypothalamus in geese.

Molecular cloning and expression analysis of the synaptotagmin-1 gene in the hypothalamus and pituitary of Huoyan goose during different stages of the egg-laying cycle.

BACKGROUND: Synaptotagmin-1 (Syt1) is an abundant, evolutionarily conserved integral membrane protein that plays essential roles in neurotransmitter release and hormone secretion. Neurotransmitters secreted by hypothalamic neurons can alter GnRH (gonadotropin-releasing hormones) neuronal activity by binding to and activating specific membrane receptors in pituitary cells and, in turn, control the release of gonadotropin hormones from the pituitary gland. To reveal the influence of Syt1 on the process of goose egg-laying, we cloned and characterized the cDNA of goose Syt1 originating from hypothalamus and pituitary tissues of Huoyan goose and investigated the mRNA expression profiles during different stages of the egg-laying cycle. METHODS: Hypothalamus and pituitary tissues were obtained from 36 Huoyan geese in the pre-laying period, early laying period, peak-laying period, and ceased period. The cDNA sequences of goose Syt1 were cloned and characterized from Huoyan goose tissues using 5'-RACE and 3'-RACE methods. Multiple alignments and phylogenetic analyses of the deduced Syt1 amino acid sequence were conducted using bioinformatics tools. The expression profiles of the Syt1 mRNA in the hypothalamus and pituitary during pre-laying, early laying, peak-laying and ceased period were examined using real-time PCR (qRT-PCR). RESULTS: The cDNA of Syt1 consisted of a 274 bp 5' UTR, a 1266 bp open reading frame (ORF) encoding 421 amino acids, and a 519 bp 3' UTR. The deduced amino acid sequence of goose Syt1 is highly conserved with the sequence from other species, especially with birds (more than 98%), and contains two protein kinase C2 conserved regions (C2 domain) from amino acids residue 157 to 259 and 288 to 402. The results of qRT-PCR demonstrated that the expression of Syt1 mRNA increased from the pre-laying period to the peak-laying period, reached its peak in the peak-laying period, and then decreased in the ceased period. CONCLUSIONS: To the best of our knowledge, this study is the first to obtain full-length cDNA sequences of the goose Syt1 gene, and the results of Syt1 mRNA expression profiling in the hypothalamus and pituitary tissues suggested that Syt1 may play an important role in regulating the secretion of hormones relevant to the reproduction and egg-laying of female geese.

Effects of dietary tryptophan on protein metabolism and related gene expression in Yangzhou goslings under different feeding regimens.

This study was conducted to investigate the effects of feeding regimens and dietary Trp levels on protein metabolism and regulation of the related gene expression in Yangzhou goslings. A 2 × 3 factorial completely randomized experiment was applied, and the treatments were designed as 2 feeding regimens (ad libitum vs. restricted feeding), and each contained 3 levels of Trp (low-Trp group, 0.14%; medium-Trp group, 0.22%; high-Trp group, 0.30%). The results show that ADG and feed conversion ratio (FCR) were significantly affected by feeding regimens (P < 0.05); dietary Trp levels influenced ADG and ADFI in the starter and overall period (P < 0.05), and interactions between Trp levels and feeding regimens on ADG, ADFI, and FCR were observed in different growing periods (P < 0.05). Serum total protein, triglycerides, and total cholesterol levels in the ad libitum group were higher than those in the restricted feeding group (P < 0.05), and the concentration of serum total protein, glucose, and insulin-like growth factor-I were higher in the medium-Trp and high-Trp groups (P < 0.05); however, serum uric acid, triglyceride, and cortisol levels were reduced in the high-Trp group (P < 0.05). Feeding regimen and dietary Trp levels affected serum glucose (P < 0.05) interactively. In the ad libitum group, tryptophanyl tRNA synthetase (TTS) mRNA expressed at a higher level in the high-Trp treatment, whereas expression of poultry target of rapamycin (pTOR) and p70 ribosomal protein S6 kinase1 (S6K1) mRNA was upregulated in the low-Trp treatment (P < 0.05). Expression and phosphorylation levels of pTOR were upregulated in thigh tissue with increased dietary Trp, but cathepsin B and 20S protease mRNA expression decreased (P < 0.05). It was concluded that the protein deposition in gosling thigh tissue was affected by dietary Trp through positive regulation of the TTS mRNA and pTOR protein expression and phosphorylation levels for protein synthesis, as well as the suppression of protein degradation-related gene expression.

The phytoestrogen daidzein may affect reproductive performance of Zhedong White geese by regulating gene mRNA levels in the HPG axis.

1. The effect of daidzein, a naturally occurring phytoestrogen, on the reproductive performance of 120 female Zhedong White geese was determined. The geese were divided into 4 groups which were fed on diets containing 0 (Control), 10 (Da1), 20 (Da2) and 30 (Da3) mg daidzein per kg diet. Egg production and weight, fertility and hatchability rates, concentrations of estradiol (E2), triiodothyronine (T3), progesterone (P4), thyroxine (T4) and growth hormone (GH) in serum, and mRNA levels of gonadotropin releasing hormone (GnRH), ß-follicle stimulating hormone (FSHß), follicle stimulating hormone receptor (FSHR), oestrogen receptor1 (ESR1), oestrogen receptor2 (ESR2), prolactin (PRL), prolactin receptor (PRLR), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in the hypothalamus-pituitary-gonadal axis (HPGA) were measured. 2. Daidzein increased egg weight and fertility but had no detectable effect on egg production and hatchability. 3. Daidzein affected serum P4 and GH concentrations and T4 rhythm, up-regulated GnRH mRNA and PRLR mRNA levels in the hypothalamus, down-regulated PRLR mRNA in the hypothalamus, PRL mRNA in the pituitary, and ESR2 mRNA levels in the ovary, respectively. The mRNA rhythms of PRLR in the hypothalamus, PRL, PRLR and FSHß in the pituitary, FSHR, ESR1 and ESR2 in the ovary were significantly changed in the Da2 group. 4. It is suggested that an appropriate dose of daidzein might improve reproductive performance by affecting serum hormone concentrations and rhythms and regulating gene mRNA levels in the HPGA of female Zhedong White geese.

Effects of dietary meals containing different levels of phytoestrogens on reproductive function in Bilgoraj ganders.

The aim of this study was to investigate how long-term feeding of ganders with diets containing different levels of phytoestrogens affects the morphometry of testes, plasma steroid levels, sperm parameters and reproductive performance. Male Bilgoraj geese were fed diets containing grass meal (with low phytoestrogen levels) and those containing alfalfa meal and soybean meal (with higher levels of phytoestrogens). Testes were obtained from ganders at the peak of mating and the ongoing laying period as well as at the beginning of photorefractoriness. The morphometric parameters were measured in frozen testicular sections. Blood was collected monthly from December to June, and plasma testosterone, androstenedione and corticosterone concentrations were determined. During the mating season, semen was collected and its quantity and quality were investigated. In the flocks (ganders with geese) reproductive output was noted. Seasonal changes were observed in the morphology of testes and in plasma testosterone, androstenedione and corticosterone concentrations in ganders. The feeding of ganders with dietary meals containing higher levels of phytoestrogens did not affect the plasma steroid contents or the majority of the morphometric parameters of testes, except for the height of the seminiferous epithelium, which was lowered. Moreover, diets with higher levels of phytoestrogens decreased the volume of ejaculates and the percentage of normal spermatozoa. However, these changes were not reflected in the fertilisation rates.