Effects of Dietary Vitamin E Supplementation on Reproductive Performance, Egg Characteristics, Antioxidant Capacity, and Immune Status in Breeding Geese during the Late Laying Period.

This study aimed to tentatively evaluate the effects of dietary vitamin E (VE) on goose reproductive physiology through the investigation of reproductive performance, egg characteristics, antioxidant capacity, and immune status in breeding geese. A total of 480 female and 96 male Jiangnan White breeding geese were randomly assigned to four treatments with four replicates, and each replicate had 30 females and six males. Four levels of VE were successively added to four treatment diets from 48 to 54 weeks of age, representing the effects of VE deficiency (0 IU/kg), basic-dose VE (40 IU/kg), middle-dose VE (200 IU/kg), and high-dose VE (2000 IU/kg). Neither the egg-laying rate nor the healthy-gosling rate were affected by any of the VE supplementations (p > 0.05). The qualified egg rate, hatchability of fertilized eggs, and spleen index were increased by each VE supplementation (p < 0.05). Egg fertility, the concentration of plasma reproductive hormones (i.e., the follicle-stimulating hormone, estradiol, and progesterone), follicular development, and antioxidant enzyme activities­i.e., the concentration of malondialdehyde (MDA), total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px)­in the liver and ovary were improved by 200 IU/kg of dietary VE (p < 0.05). Plasma VE concentration, immunoglobulin A, and immunoglobulin G content were increased, whereas plasma vitamin D3 concentration was reduced by increasing dietary VE levels to 2000 IU/kg (p < 0.05). The VE deposition of yolk, the yolk color depth, and the albumen rate were increased by each VE supplementation (p < 0.05). Antioxidant enzyme activities (i.e., MDA concentration, T-AOC, SOD, and GSH) in yolk were improved by 200 IU/kg and 2000 IU/kg of dietary VE (p < 0.05), compared with 0 IU/kg. The VE deposition was significantly correlated with GSH activity and the MDA concentration in egg yolk (p < 0.05). However, the high intake of dietary VE (2000 IU/kg vs. 200 IU/kg) decreased egg fertility (p < 0.05) and reduced the antioxidant capacity in the liver and ovary (p < 0.05). The qualified egg rate was positively correlated to immunoglobulin production (p < 0.05). Egg fertility and hatchability were correlatively improved by increased antioxidant enzyme activity; decreased MDA in the liver and ovary; hatchability; and enhanced immune status (p < 0.05). To sum up, both VE deficiency and high-dose VE (2000 IU/kg) reduced reproductive performance, whereas a dose of 200 IU/kg VE achieved optimal fertility, possibly through enhancing antioxidant capacity and immune status.

The effect of different dietary levels of sodium and chloride on performance, blood parameters and excreta quality in goslings at 29 to 70 days of age.

The purpose of this study was to ascertain the appropriate levels of dietary sodium (Na+ ) and chloride (Cl- ) for 29- to 70-day-old goslings and to investigate the effects of different levels of Na+ and Cl- on the growth performance, water consumption, blood parameters and excreta quality of goslings to provide a reference for the healthy production of goslings. In Experiment 1, a total of 432 29-day-old male Jiangnan White goslings were randomly allotted to nine treatments according to a 3 × 3 factorial design, with six pens containing eight birds per treatment. The goslings were fed diets with three concentrations of Na+ (0.10%, 0.15% and 0.20%) and three concentrations of Cl- (0.15%, 0.20% and 0.25%). The experimental period was 42 days. In Experiment 2, a total of 24 70-day-old Jiangnan White goslings were selected for four treatments (0.10% Na+  × 0.15% Cl- ; 0.10% Na+  × 0.25% Cl- ; 0.20% Na+  × 0.15% Cl- and 0.20% Na+  × 0.25% Cl- ) and housed separately in metabolic cages. The faeces were collected for 3 consecutive days. In Experiment 1, the average daily feed intake (ADFI), average daily gain (ADG) and feed/gain (F/G) ratio of goslings were unaffected by the treatments. However, low levels of Na+ and Cl- significantly reduced the water consumption of goslings in the later growth period (p < 0.05). The average water consumption of goslings fed with 0.10% Na+  × 0.15% Cl- was significantly lower than that of the goslings fed with 0.20% Na+  × 0.25% Cl- (56 days, 1304.2 ml vs. 1471.7 ml; 63 days, 1452.8 ml vs. 1610.8 ml; 70 days, 1540.0 ml vs. 1775.4 ml; p < 0.05). The interaction between Na+ and Cl- (Na+  × Cl- ) had a significant impact on the blood haemoglobin (HGB) and haematocrit (HCT) levels in the goslings (p < 0.05). HGB increased linearly with increasing levels of Na+ . HGB and HCT first increased and then decreased with increasing levels of Cl- . In Experiment 2, Na+ and Cl- levels had significant effects on the excreta moisture content (p < 0.05). Goslings fed with 0.10% Na+  × 0.15% Cl- had a low moisture content of 5.58% compared to the goslings fed with 0.20% Na+  × 0.25% Cl- (87.51% vs. 93.09%; p < 0.05). The levels of dietary Na+ had a significant effect on the retention ratio of Na (p < 0.05), with the value for the 0.20% Na+ group being significantly higher than that for the 0.10% Na+ group (p < 0.05). In summary, different levels of Na+ and Cl- did not affect the growth of goslings. To reduce the water consumption and moisture content of excreta, the Na+ and Cl- levels in the diet can be as low as 0.10% and 0.15%, respectively.

Identification of Laying-Related SNP Markers in Geese Using RAD Sequencing.

Laying performance is an important economical trait of goose production. As laying performance is of low heritability, it is of significance to develop a marker-assisted selection (MAS) strategy for this trait. Definition of sequence variation related to the target trait is a prerequisite of quantitating MAS, but little is presently known about the goose genome, which greatly hinders the identification of genetic markers for the laying traits of geese. Recently developed restriction site-associated DNA (RAD) sequencing is a possible approach for discerning large-scale single nucleotide polymorphism (SNP) and reducing the complexity of a genome without having reference genomic information available. In the present study, we developed a pooled RAD sequencing strategy for detecting geese laying-related SNP. Two DNA pools were constructed, each consisting of equal amounts of genomic DNA from 10 individuals with either high estimated breeding value (HEBV) or low estimated breeding value (LEBV). A total of 139,013 SNP were obtained from 42,291,356 sequences, of which 18,771,943 were for LEBV and 23,519,413 were for HEBV cohorts. Fifty-five SNP which had different allelic frequencies in the two DNA pools were further validated by individual-based AS-PCR genotyping in the LEBV and HEBV cohorts. Ten out of 55 SNP exhibited distinct allele distributions in these two cohorts. These 10 SNP were further genotyped in a goose population of 492 geese to verify the association with egg numbers. The result showed that 8 of 10 SNP were associated with egg numbers. Additionally, liner regression analysis revealed that SNP Record-111407, 106975 and 112359 were involved in a multiplegene network affecting laying performance. We used IPCR to extend the unknown regions flanking the candidate RAD tags. The obtained sequences were subjected to BLAST to retrieve the orthologous genes in either ducks or chickens. Five novel genes were cloned for geese which harbored the candidate laying-related SNP, including membrane associated guanylate kinase (MAGI-1), KIAA1462, Rho GTPase activating protein 21 (ARHGAP21), acyl-CoA synthetase family member 2 (ACSF2), astrotactin 2 (ASTN2). Collectively, our data suggests that 8 SNP and 5 genes might be promising candidate markers or targets for marker-assisted selection of egg numbers in geese.