• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.7
• /
• pp.1090-1095
• /
• 1999

In order to minimize the occurrence of fatty liver, this study investigated how adding a high level of dietary choline or methionine affected the lipid metabolism of Tsaiya ducks. Feeding trials were conducted with sixty Tsaiya ducks during their growing period, when they were 8-12 weeks old, and during their laying period, 10-14 weeks after the onset of laying when they were 26-30 weeks old. The ducks were randomly assigned to one of three groups: a control group (basal diet), a group in which methionine was added to the basal diet, and a group in which choline was added to the basal diet. The levels of methionine and choline added were twice as high as the levels recommended by the NRC for layer-type chickens. Experimental results indicated that adding choline to the basal diet of growing ducks significantly (p<0.05) increased their body weight, while adding methionine significantly (p<0.05)reduced their body weight. Adding either choline or methionine reduced the ducks' liver fat content in both the growing and the laying periods (p<0.05). Ducks receiving added methionine or choline in their diets displayed enhanced egg production (p<0.05). Adding choline increased serum triacylglycerol (TG) in the laying period (p<0.05). Adding either choline or methionine did not significantly (p>0.05) affect the t-globulin level. Adding methionine increased the activity of liver malic dehydrogenase in both the growing and the laying periods, and increased fatty acid synthetase in the laying period (p<0.05). While adding choline markedly (p>0.05) increased VLDL and apo B in both the growing and the laying periods, it decreased HDL and apo A in the laying period (p<0.05). This study found that adding a high level of choline to the basal diets of Tsaiya ducks in both the growing and the laying periods had beneficial effects. Furthermore, adding methionine affected the lipid metabolism of Tsaiya ducks to a lesser extent than adding choline.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.3
• /
• pp.403-408
• /
• 2003

The study investigated the lipid metabolism of Tsaiya ducks under fasting and ad libitum feeding conditions. Sixty Tsaiya ducks in their growing period (8-12 wk-old) and sixty Tsaiya ducks in their laying period (26-30 wk-old, 10-14 weeks after the onset of laying) were randomly divided into ad libitum feeding and 3-day fasting groups. The activities of lipid metabolism related enzymes were determined. Experimental results indicated that fasting depressed the activities of lipogenesis related enzymes such as fatty acid synthetase and NADP-malic dehydrogenase in both periods (p<0.05). Fasting also increased the activities of liver fatty acid $\beta$-oxidation enzymes (p<0.05). However, the activities of lipoprotein lipase in adipose tissue, heart and ovarian follicle in both periods and the hormone-sensitive lipase of adipose tissue in the growing period were decreased by fasting (p<0.01).

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.7
• /
• pp.1047-1053
• /
• 2006

The current study was designed to determine the effects of dietary docosahexaenoic acid (DHA) on fatty acid deposition in egg yolk and various tissues of laying Tsaiya ducks, and on the mRNA concentrations of hepatic lipogenesis-related transcription factors. Thirty laying ducks were randomly assigned to three treatments with diets based on corn-soybean meal (ME: 2803 kcal/kg; CP: 17.1%; Ca: 3.4%) supplemented with 0% (control diet), 0.5% or 2% algal DHA oil. The DHA content in egg yolks of the ducks was elevated significantly (p<0.01) with the supplementation of dietary DHA. The DHA percentage of the total fatty acids in the egg yolk of laying ducks was 0.5%, 1.3% and 3.4% for 0%, 0.5% and 2% algal DHA oil treatments, respectively, for the $1^{st}$ week, and 0.5%, 1.5% and 3.3% for the $2^{nd}$ week. Therefore, algal DHA oil can be utilized by laying Tsaiya ducks to enhance the egg-yolk DHA content. The concentrations of triacylglycerol (TG) and cholesterol in plasma of laying Tsaiya ducks were not affected by dietary DHA treatments (p>0.05). The DHA concentration in plasma, liver, and skeletal muscle was increased with the addition of dietary algal DHA oil (p<0.05). The mRNA abundance of sterol regulatory element binding protein 1 (SREBP1) and SREBP2 in the livers of laying Tsaiya ducks was not affected by dietary DHA, suggesting that the expression of these transcription factors is tightly controlled and not sensitive to DHA treatments.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.2
• /
• pp.217-224
• /
• 1992

The study was undertaken to determine the effect of dietary magnesium on the eggshell quality and other performance in laying Tsaiya ducks and Leghorn hens. Twenty-five Tsaiya ducks and 25 Leghorn hens were raised in individual cages. The basal diet was mainly consisted of corn starch and isolated soybean protein. At the beginning of the experiments, birds were fed for 10 days with the basal diet supplemented with 500 mg/kg Mg (1070 mg/kg in total by analysis) in order to allow the birds adapting to the new diet. Both Tsaiya ducks and Leghorn hens were then each randomly divided into five groups and each group of five birds were fed with the experimental diets containing 690, 1070, 1690, 2150 or 2380 mg/kg Mg, respectively for 21 days. Eggs were collected in order to measure eggshell quality, Mg and Ca content of the eggshell. At the end of the experiments, blood samples of all birds were taken from their brachial veins for measuring the concentration of Mg and Ca in the plasma. Experimental results appeared that the dietary Mg content did not significantly affect egg production, egg weight, eggshell breaking strength and thickness in both Tsaiya ducks and Leghorn hens. In Tsaiya ducks, however, the plasma Mg concentration was affected by the dietary Mg content, but the plasma Mg almost reached a plateau (4.66 mg/dl) as long as the dietary Mg level was over 1070 mg/kg. In Leghorn hens, the plasma Mg level was significantly increased from 1.66 mg/dl to 4.03 mg/dl when the dietary Mg content in the diet had been increased from 690 mg/kg to 2380 mg/kg, suggesting that the plasma Mg concentration seems to be directly influenced by the Mg absorbed in the intestine. In the Tsaiya ducks, however, the dietary Mg level did not significantly affect the eggshell Mg content (from 0.113% to 0.123%). Whereas, there was a negative correlation between the eggshell thickness and eggshell Mg content (r = -0.50, p<0.01), revealing that the increase in eggshell Mg content probably associated with the impairment of eggshell quality in Tsaiya ducks. In Leghorn hens, however, there was no significant correlation between eggshell quality and eggshell Mg content, although the Mg content in the eggshell was also increased from 0.279% to 0.427% when the dietary Mg had been elevated from 690 mg/kg to 2380 mg/kg.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.6
• /
• pp.888-901
• /
• 2020

Objective: A set of microsatellite markers with high polymorphism from Tsaiya duck were used for the genetic monitoring and genetic structure analysis of Brown and White Tsaiya duck populations in Taiwan. Methods: The synthetic short tandem repeated probes were used to isolate new microsatellite markers from the genomic DNA of Tsaiya ducks. Eight populations, a total of 566 samples, sourced from Ilan Branch, Livestock Research Institute were genotyped through novel and known markers. The population genetic variables were calculated using optional programs in order to describe and monitor the genetic variability and the genetic structures of these Tsaiya duck populations. Results: In total 24 primer pairs, including 17 novel microsatellite loci from this study and seven previously known loci, were constructed for the detection of genetic variations in duck populations. The average values for the allele number, the effective number of alleles, the observed heterozygosity, the expected heterozygosity, and the polymorphism information content were 11.29, 5.370, 0.591, 0.746, and 0.708, respectively. The results of analysis of molecular variance and principal component analysis indicated a contracting Brown Tsaiya duck cluster and a spreading White Tsaiya duck cluster. The Brown Tsaiya ducks and the White Tsaiya ducks with Pekin ducks were just split to six clusters and three clusters when K was set equal to 6 and 3 in the Bayesian cluster analysis. The individual phylogenetic tree revealed eight taxa, and each individual was assigned to its own population. Conclusion: According to our study, the 24 novel microsatellite markers exhibited a high capacity to analyze relationships of inter- and intra-population in those populations with a relatively limited degree of genetic diversity. We suggest that duck farms in Taiwan could use the new (novel) microsatellite set to monitor the genetic characteristics and structures of their Tsaiya duck populations at various intervals in order to ensure quality breeding and conservation strategies.

• Asian-Australasian Journal of Animal Sciences
• /
• v.16 no.2
• /
• pp.290-296
• /
• 2003

Tsaiya ducks and Leghorn hens are the two major laying birds raised in Taiwan. They are all excellent egg layers. Tsaiya ducks are small in body size (1.3 kg) with bigger egg weight (65 g) and stronger eggshell breaking strength than eggs from hens. The eggshell consists mainly of calcium carbonate, hence calcium plays an important role in the eggshell formation. Magnesium is also present in eggshell in small amounts, which may have effect on maintaining eggshell quality. In comparison studies, it was shown that the duck eggshells contained higher calcium and lower magnesium content than chicken eggshells. The eggshell magnesium content was not affected by the dietary magnesium levels (690-2380 ppm) in ducks, but in hens, it increased linearly with dietary magnesium levels. The palisade layer ($5000{\times}$) of the eggshell was found to have a compact form for ducks while there are many hallow vesicles in chicken eggshells. The eggshell magnesium deposition model is different for ducks and hens with ducks having a one-peak and hens having a two-peak model. The calcium deposition model is similar for both birds. Both the carbonic anhydrase specific activity and total activity in the shell gland mucosa of ducks are higher than those in hens. Ducks retain higher magnesium and lower calcium in the shell gland mucosa and secret less magnesium and more calcium into the shell gland lumen for eggshell deposition. The ATPase specific activity is maintained fairly constant during the eggshell forming stage, indicating continuous calcium transport into the shell gland lumen for eggshell formation. The magnesium content in duck eggshells is much lower than that in hens indicating that the magnesium content in the eggshell may have an effect on eggshell quality.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.8
• /
• pp.1258-1262
• /
• 1999

With an attempt to elucidating the lipid metabolism of Tsaiya ducks, thirty ducks at growing (8 weeks of age) and laying periods (10 weeks after the onset of laying) were examined, respectively. The ducks were randomly allocated into ad libitum feeding and 3-day fasting groups, to investigate their in vitro hepatocytes lipogenesis capacity and adipocytes lipolysis rate. Results indicate that (1) the capacity of hepatocytes incorporation of glucose and acetate into total lipid and metabolite of $^{14}CO_2$ production during the laying period was greater than during the growing period. Approximately 50% of the glucose or acetate converted into triacylglycerol (TG) by the hepatocytes were recovered as fatty acid during the growing period, while it was 65-70% during the laying period. (2) Acetate used for lipogenesis ability was superior to glucose in both periods. (3) The adipocytes lipolysis rate was increased significantly (p<0.05) by fasting. In contrast, the capacity of incorporated glucose or acetate into total lipid, triacylglycerol, fatty acid and glycerol by hepatocytes was reduced significantly (p<0.05) by fasting.

• Asian-Australasian Journal of Animal Sciences
• /
• v.2 no.2
• /
• pp.67-75
• /
• 1989

Studies were conducted to compare the utilization of dietary calcium between brown laying Tsaiya duck and Leghorn hen. Birds were fed corn-soybean diets containing 1.0, 2.0, 3.0, 4.0 and 5.0% calcium, respectively, with five birds per treatment. The metabolizability of calcium was determined by the indicator method. Experiments were conducted three times each at the age of 27, 31 and 36 weeks. Results appeared that duck eggs were heavier with better shell quality in comparison with hen eggs. Ducks fed 1% calcium diet resulted in severely depressed egg production (19%), but not for hens which still had 56% egg production. The metabolizability of calcium for hens was significantly higher than that for ducks (P<0.05) when both were fed diets containing 1 or 2% calcium. As the dietary calcium level was increased to 3 to 5%, there was no significant difference in calcium metabolizability between ducks and hens. When the dietary calcium was between 2 to 5%, the ducks retained more calcium than did the hens. Plasma calcium content for both hens and ducks fed 1% calcium diet was about the same. When the amount of the dietary calcium was increased to 2-5%, the plasma calcium level of ducks was approximately 7-10 mg/dl higher than that of hens. The calcium content in the egg shell of duck was significantly higher than that of hens, too. As the dietary calcium level was increased, there was a decreased magnesium content in the eggshell of hens, but not for ducks. The magnesium level in the eggshell was higher in hens than that in ducks. It is concluded that ducks could retain significantly more calcium and maintain higher plasma calcium level which might be the reason for larger eggs with better shell quality by ducks.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.7
• /
• pp.984-989
• /
• 2004

Three hundred and twelve female Tsaiya ducks from four lines (L1051, L1052, L1053 and L1054) were used in this study to investigate the changes in plasma calcium and inorganic phosphorus levels, blood pH, carbon dioxide partial pressure (pCO$_{2}$), bicarbonate ion concentration ($HCO_{3}^{-}$), and base excess (BE) during laying periods. The results indicated that plasma calcium and inorganic phosphorus concentration at 40 and 50 wks of age were higher (p<0.05) than those at other ages. Significant positive correlation coefficients were found between plasma calcium and inorganic phosphorus levels at each age tested from 20 to 50 wks. Ducks from L1053 showed lower (p<0.05) blood pH, BE and $HCO_{3}^{-}$ as compared with other lines. Ducks from L1054 had higher (p<0.05) blood pH, BE and $HCO_{3}^{-}$ than those of other lines showing that there were some differences on blood parameters among lines. Eggshell strength decreased with age up to 65 wks and remained constant thereafter. Egg weight increased gradually from 30 to 60 wks and decreased slightly after 70 wks of age. Plasma inorganic phosphorus level in 40 and 50 wks old birds was positively correlated with eggshell strength, while blood $HCO_{3}^{-}$ in 40 and 50 wks old birds was negatively correlated with eggshell strength.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.3
• /
• pp.331-337
• /
• 1993

In order to understand the effect of duck hepatitis B virus (DHBV) on the economic performance of ducks, Three groups (DHBV congenitally infected, experimentally infected and DHBV negative) Brown Tsaiya ducks (Anas platyrhyncha) were used for experimental animals. Artificial insemination and pedigree hatching were applied in the propagation of ducklings, and the efficiency of vertical transmission and experimental infection was analyzed through the detection of DHBV DNA in the sera of 8-week-old offspring. The observation of the records of the first year indicated that the persistent infection had no significant effects on the performance of ducks, except the egg number of survival ducks up to 40 week of age. Thus DHBV infection did not appear to give ill effects to the economic performance of ducks in first laying year. A higher infection rate (85.3%) was obtained in congenital transmission than that (75.5%) of experimental infection. Both modes of infection did not reach 100% infectious rate, although some ducks developed transient viraemia in a tracing of DHBV DNA for 24 weeks to 11 challenged ducklings.