White Peking Duck Research Articles

Study of composition and properties of duck meat

The work is devoted to the essential task of scientific justification of the use of waterfowl meat in the meat products technology. The objects of the study were the white Peking ducks, the muscovy ducks and the mulard hybrid ducks. In the comparative aspect, the gravimetric parameters of the main dressing parts of the duck carcasses, their tissue composition, total chemical composition (moisture, protein, fat, mineral substances), the fractional composition of meat proteins, the content of macroelements (potassium, calcium, magnesium, phosphorus) and microelements (Ferrum, zinc) were studied. The energy value of the duck meat, its functional and technological properties was determined, and the microstructure of the muscle tissue of the breast and thigh parts of the carcass was studied. The comparative analysis showed that the meat of the Peking duck is inferior to the meat of the muscovy duck and the mulard duck in protein content, but exceeds it in fat content. The most significant portion of the muscle tissue is concentrated in the breast and leg quarter. The meat of the Peking duck has a higher caloric content compared to that of the muscovy and the mulard duck. Duck meat is rich in potassium, calcium, magnesium, as well as Ferrum and zinc. Duck meat can be used as a functional raw material because these mineral substances are often scarce in the diet of a modern human. High functional and technological properties of duck meat provide high-quality indicators of the finished product.

Duration of the flaxseed diet promotes deposition of n-3 fatty acids in the meat and skin of Peking ducks.

BackgroundPolyunsaturated fatty acids (PUFA), particularly n-3, have beneficial effects on human health, and for this reason foodstuffs with increased content of n-3 PUFA are now very common and widely available.DesignThis study was conducted to investigate the effect of the duration of a flaxseed diet on Peking duck’s growth performance, antioxidant status, gene expression, and fatty acid profile of the meat. A total of 792 12-day-old white Peking ducks were divided into four groups. In the control group, animals were provided with a basal diet. In the three experimental groups, animals were fed a 10% flax seed diet with vitamin E at 13, 23, and 33 days of age for 30, 20, and 10 days, respectively.ResultsThe growth performance of the ducks decreased with flaxseed diet’s duration. Both body weight and body weight gain decreased linearly while Feed conversion ratios (FCR) increased in the group of ducks fed flaxseed compared to control ducks. Serum triglycerides (TG), very low density lipoprotein (VLDL), low density lipoprotein cholesterol (LDL-C), and aspartate aminotransferase (AST) linearly decreased while high density lipoprotein cholesterol (HDL-C) and lipopolysaccharide (LPS) levels increased by feeding flaxseed up to 30 days. The expression of lipin-1 gene (LPIN-1) and fatty acid desaturase 2 (FADS2) linearly increased in ducks fed flaxseed for 30 days. Linolenic acid (n-3) and its long-chain metabolites like eicosatetraenoic acid (ETA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total n-3 fatty acids (FA) linearly increased while the ratio of n-6 to n-3 was reduced with increased duration of flaxseed supplementation.ConclusionOverall, we found that increasing the duration of flaxseed diet with vitamin E for more than 10 days had a mild adverse effect on duck’s growth performance but enrichedits meat with long-chain PUFA and decreased the n-6 to n-3 ratio, providing quality meat for health-conscious consumers. A period of 20 days is good for producing n-3 enriched Peking duck meat and skin.

Flaxseed diet caused inflammation by altering the gut microbiota of Peking ducks

To study why flaxseed supplementation causes adverse effects on the performance of poultry, we investigated the gut microbiota of Peking ducks after consumption of a flaxseed diet. A total of 792, 12-day-old white Peking ducks were divided into four groups. In the control group, birds were provided with a basal diet. In the three experimental groups, the birds were fed flaxseed containing diet (10% flaxseed and 90% basal diet) for 30, 20 and 10 d, respectively. On day 42, ceca were collected to evaluate the bacterial diversity of the gut microbiota using microbial 16S rDNA gene profiling; serums were obtained to determine the levels of inflammatory mediators. The flaxseed diet decreased the alpha diversity and shifted the predominant genera of the gut microbiota. Flaxseed-fed groups had higher abundances of Escherichia/Shigella (p < 0.1) and Campylobacter (p < 0.05) than the control group. The abundance of pro-inflammatory bacteria such as Veillonellaceae increased (p < 0.05) at first and then decreased (p < 0.05) with prolonged flaxseed supplementation. The levels of prostaglandin E2 and Leukotriene B4 in serum showed the same pattern as that of the pro-inflammatory bacteria. In conclusion, flaxseed diets are associated with inflammation by altering the cecal microbiota dynamics.

A comprehensive analysis of the germline and expressed TCR repertoire in White Peking duck

Recently, many immune-related genes have been extensively studied in ducks, but relatively little is known about their TCR genes. Here, we determined the germline and expressed repertoire of TCR genes in White Peking duck. The genomic organization of the duck TCRα/δ, TCRγ and unconventional TCRδ2 loci are highly conserved with their counterparts in mammals or chickens. By contrast, the duck TCRβ locus is organized in an unusual pattern, (Vβ)n-Dβ-(Jβ)2-Cβ1-(Jβ)4-Cβ2, which differs from the tandem-aligned clusters in mammals or the translocon organization in some teleosts. Excluding the first exon encoding the immunoglobulin domain, the subsequent exons of the two Cβ show significant diversity in nucleotide sequence and exon structure. Based on the nucleotide sequence identity, 49 Vα, 30 Vδ, 13 Vβ and 15 Vγ unique gene segments are classified into 3 Vα, 5 Vδ, 4 Vβ and 6 Vγ subgroups, respectively. Phylogenetic analyses revealed that most duck V subgroups, excluding Vβ1, Vγ5 and Vγ6, have closely related orthologues in chicken. The coding joints of all cDNA clones demonstrate conserved mechanisms that are used to increase junctional diversity. Collectively, these data provide insight into the evolution of TCRs in vertebrates and improve our understanding of the avian immune system.

Early Diet Dilution with 40% Rice Hull Induces Lower Body Fat and Lipid Metabolic Programming in Peking Ducks

This study was conducted to evaluate the effect of early diet dilution with 40% rice hull on growth performance, carcass characteristic and composition of meat-type ducks, and to reveal the possible mechanism for decreased body fat deposition. 160 1-day-old White Peking ducks with initial body weight of <TEX>$44.5{\pm}1.0$</TEX> g were allotted to two treatments with 8 replicate pens per treatment and 10 ducks per pen (5 male and 5 female). Ducks were fed with the experimental starter diets diluted with 0% (control, RH0), 40% rice hull (RH40) during 8 to 14 d of age, respectively. Thereafter, all ducks were fed with grower diet. Ducks fed with RH40 diet from 8 to 14 d of age increased (p<0.05) feed intake, decreased (p<0.05) body weight, body weight gain and adjusted feed intake (excluded rice hull), abdominal fat, skin with fat, and fat content in carcass, and reduced (p<0.05) activities of hepatic malic dehydrogenase, glucose-6-phosphate dehydrogenase and fatty acid synthetase. When diet dilution was withdrawn in the re-fed period from 15 to 42 d of age, full compensatory growth of body weight, breast meat and leg meat weight were attained. However, ducks were still less (p<0.05) carcass fat content and showed continually lower (p<0.05) hepatic lipogenic enzyme activities at the market age in RH40 ducks than the control. These results indicated that diluting diet with 40% rice hull during 8 to 14 d of age might be a suitable method to improve feed efficiency, and to reduce carcass fat deposition in the production of meat-type ducks.

TRAILS TO IMPROVE GROWTH AND CARCASS QUALITY IN DUCK

Reducing fat in duck lean is consider the first step towards improvingcarcass quality. A total of 144 male and female, one day old whitePeking ducks were divided into 6 equal groups, each group subdividedinto 2 subgroup. One of them contain 12 males while the other contain12 females.Six dietary treatments were applied for both males and females havethe same group number. Basal diet supplemented with salbutamole 2mgfor 56 days (whole experiment period)(Treatment 1), or from 29-56days of age)(Treatment 2), basal diet supplemented with ChromiumPiclonate 2mg)(Treatment 3), modified calorie protein ratio diet byincreasing protein concentration 0.5 % (0-2 weeks) and 2 % (3-8 weeks)(Treatment 4), basal diet but after reduce the recommended level to 95%of control diet for starter period and to 90% of control diet for growerand finisher periods)(Treatment 5), while basal diet without supplementation,modification, or restriction was as control (Treatment 6). The results concerning growth performance demonstrated that salbutamolor chromium supplementation and decreased calorie protein ratioimproved all parameters of growth performance. While restricted dietreduced final body weight and final body weight gain but feed conversionratio was improved.Carcass traits showed that dressing percentage and breast muscle wasincreased. Skin and sub-cuteness Fat percentage was decreased. Meanwhile,abdominal fat was reduced significantly with all dietary treatmentsas compared with control. Also, chemical analysis of meat demonstratedthat muscular fat was decreased significantly in all treatmentscompared with control, however, moisture content was increased.Serum analysis showed that total cholesterol was decreased with alldietary treatments while serum protein increased insignificantly in allfemale groups but was significantly increased in all male groups ascompared with control.It could be concluded that salbutamole and chromium supplementationor decreased calori protein ratio improved all growth performance,but restricted diet reduced final body weight while feed conversionratio improved. Dressing percentage and carcass characteristics wereimproved with all dietary treatments. And cholesterol and cholesterolL.D.L. reduced with all experimental treatments in both sexes comparedwith control.

Effects of Dietary Metabolizable Energy and Crude Protein Content on the Activities of Digestive Enzymes in Jejunal Fluid of Peking Ducks

The response of digestive enzymes activities in the jejunal fluid of Peking ducks to dietary ME and CP content was investigated. In experiment 1, jejunal digesta from 24 cannulated male white Peking ducks of 18 wk of age were collected for 1 h out of every 4 h beginning at 0930 h on d 16, 18, and 20 of the experiment. The activities of amylase, trypsin, and chymotrypsin in jejunal fluid were determined. In experiment 2, 72 male cannulated ducks were randomly sorted into 4 groups. Four treatments consisted of combinations of 3,050 and 2,800 kcal/kg of ME, and 17.50 and 14.40% CP content were available ad libitum. Jejunal digesta samples were collected for 1 h every 4 h from 0930 to 1830 h on d 31, 33, and 35 of the experiment according to the results of experiment 1. The activities of amylase, trypsin, chymotrypsin, lipase, sucrase, and maltase in jejunal fluid were determined. In experiment 1, significant differences were found in the average activities of amylase and chymotrypsin among days. The collection time significantly affected the 3 enzyme activities, and average enzyme activities during the day were higher and more stable than during the night. In experiment 2, the effect of dietary ME content on the 6 digestive enzymes activities was not significant. But the dietary protein content significantly changed amylase, trypsin, and chymotrypsin activities.

Methionine Requirements of Male White Peking Ducks from Twenty-One to Forty-Nine Days of Age

A dose-response experiment with 6 dietary methionine levels (0.20, 0.275, 0.35, 0.425, 0.50, and 0.575%) was conducted with male White Peking ducklings to estimate the methionine requirement of growing ducks from 21 to 49 d of age. One-day-old male White Peking ducklings were fed common starter diets from hatching to 21 d of age and then fed the experimental diets from 21 to 49 d of age. Three hundred thirty-six 21-d-old birds were allotted to 24 pens with 14 birds per pen according to similar pen weight. There were 6 dietary treatments, each containing 4 replicate pens. At 49 d of age, weight gain, feed intake, and feed/gain of ducks from each pen were measured, and 2 ducks selected randomly from each pen were slaughtered to evaluate the yields of abdominal fat, breast meat (including pectoralis major and pectoralis minor), and leg meat (including thigh and drum stick). Significant effects of dietary methionine on weight gain, breast meat, and abdominal fat were observed. Both weight gain and breast meat yield showed significant quadratic response to increasing dietary methionine, and abdominal fat decreased linearly (P < 0.05). According to the quadratic model, the optimal methionine requirement of male White Peking ducks from 21 to 49 d of age for maximum weight gain and breast meat yield were 0.377 and 0.379%, respectively.

The Mesencephalic Trigeminal Nucleus of the Duck: Development and Apoptosis

The normal development of the mesencephalic trigeminal nucleus (MesV) of the white Peking duck (Anas platyrhynchos) was studied from the 9th day of incubation until hatching and during adulthood. In the early days of embryonic development, neurons are present in the posterior commissure and in the mesenchymal tissue outside the leptomeninges in addition to those in the tectal commissure (TC) and in the optic tectum. Following the internucleosomal cleavage of DNA, a massive loss of neurons in the MesV starts in the 11-day embryo and continues until the 15th day of incubation. On the 16th day, the nucleus consists of a numerically larger medial division located in the TC and a smaller lateral division within the stratum griseum periventriculare as is found in the adult animal. The programmed cell death occurring in the MesV is discussed herein and correlated with the analogous apoptotic phenomena observed in the trigeminal motor nucleus.

Electron microscopic studies on duck hepatitis B virus particles in hepatocytes and sequential changes in various patterns of infection

To investigate the critical factors involved in the elimination of the duck hepatitis B virus (DHBV) in acute infection, the sequential changes in the number of DHBV particles in hepatocytes were studied electron microscopically in ducks experimentally infected by DHBV. Twenty Japanese white Peking ducks were infected with DHBV on the day of hatching, and on the 7th day and 14th day after hatching. Inoculation of DHBV on the day of hatching, and on the 7th and 14th day after hatching resulted in persistent viremia, transient viremia and no viremia, respectively in ducks as tested by spot hybridization assay. The number of DHBV particles in the liver correlated well with the amount of serum DHBV-DNA, DHBV particles decreased in hepatocytes without any interaction of inflammatory cells over the observation period, and the number of particles was not associated with the degree of hepatic inflammation. From these results, the elimination of the virus was thought to be induced by a reduction of viral replication in the hepatocytes and not by destruction of their host cells. There must be an age-dependent factor which strongly suppresses the viral replication.

Age-dependent Changes of the Chemical and Energy Composition in Ducks During the First Eight Post-hatching Weeks

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Chemical Composition and Energy Content of Duck Feathers in the Post-hatching Period

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Olfaction in peking ducks (Anas platyrhynchos): A comparative study of centrifugal and centripetal olfactory connections in young ducks and in embryos and ducklings (Aves)

Our study of young white Peking ducks (Anas platyrhynchos) revealed that their main olfactory centres are very similar to those reported for pigeons. Additionally, two major olfactory tracts and other olfactory centres were found to be intimately associated with telencephalic and diencephalic limbic structures. Our results make it possible to reject the view that olfaction in birds is not connected with the limbic system, as is the case in other vertebrates. The occurrence of olfaction was found to be considerably higher in embryos and ducklings. Embryonic connections are more extensive than the olfactory structures of young ducks, covering the archipallial wall of the hemisphere, i.e. the dorsomedial hippocampus and the main laminae of the forebrain. Transitory centripetal olfactory connections develop in embryos, and centrifugal olfactory connections are present in ducklings at the time of hatching. Controls revealed that a portion of the olfactory connections is drastically reduced by physiological degeneration involving connections emanating from both directions. Ultrastructural examination of embryonic archipallial structures revealed that the degeneration is partially the result of the dispersal of innervated neurons. Phylogenetically, one may compare the significant involvement of transitory olfactory connections in the anlage of limbic structures with the conditions occurring in anamniot vertebrates. This supports the hypothesis that the primary development of transitory olfactory connections represents an ontogenetic recapitulation of ancestral conditions, by which the structural and functional organization of the avian brain is influenced.

Myasthenia gravis immunoglobulin augments motor neuron survival without producing muscle paralysis.

Effects of sera or immunoglobulins from patients with acquired myasthenia gravis on motor neuron survival during critical stages of embryonic development were investigated in the trochlear nucleus-superior oblique muscle system of white Peking duck embryos. A significant increase in motor neuron survival occurred following application of myasthenia gravis sera or myasthenic immunoglobulin during the period of embryonic death of motor neurons. There was no reduction in limb or extraocular muscle movement in treated embryos. Trochlear motor neuron survival persisted after sera or immunoglobulin treatment was discontinued. The total number of muscle fibers and acetylcholine receptors were unchanged following immunoglobulin treatment. Myasthenic immunoglobulin is therefore unique in preventing motor neuron death without producing muscle paralysis and in promoting a prolonged augmentation of motor neuron survival. It is concluded that factors other than muscle activity may also control neuron survival during embryogenesis. Previous studies of myasthenic sera in muscle have shown effects only postsynaptically. This is the first demonstration that myasthenic immunoglobulin affects structures in the central nervous system.

Neural control of embryonic acetylcholine receptor and skeletal muscle.

The manner by which motor neurons exert control over the distribution and number of acetylcholine receptors, and muscle development was investigated in the superior oblique muscle of white Peking duck embryos. Clusters of receptors in the normally developing muscle first appeared on day 10 of incubation as determined with I125 alpha-bungarotoxin autoradiography. The initial appearance of receptor clusters coincided with the arrival of motor nerve fibers in the muscle. Clusters of receptors also appeared in normal fashion in muscles made aneural by destruction of motor neurons on day 7. But after day 14 these clusters had disappeared and no new clusters were seen thereafter in the aneural muscle. Receptor clusters persisted throughout development in muscle in which neuromuscular transmission was blocked with either curare or botulinum toxin and in muscles denervated on day 10.5, i.e., shortly after the initial nerve-muscle contact but prior to the onset of muscle activity. A progressive increase in the total number of receptors and in the total amount of protein occurred during the course of normal development. However, the specific activity of the receptor protein declined sharply following innervation on day 10. The total number of receptors and the specific activity of the receptor was affected depending on whether the motor neurons were destroyed before or after innervation and following chronic blockade of neuromuscular transmission. The half-life of the receptor protein was similar in normal, aneural, and paralyzed muscles (26, 25, 26 h, respectively). Measurements of total protein indicated that essentially no muscle growth occurred in the complete absence of innervation. Paralyzed muscles continued to develop but at a slower pace.

Influence of neostigmine treatment on embryonic development of acetylcholine receptors and neuromuscular junctions.

The postulated role of the acetylcholine receptor in the formation of neuromuscular synapses during the course of embryonic development was investigated in the superior oblique muscle of white Peking duck embryos. The possibility that the number of receptors could be experimentally lowered by chronic injections of the anticholinesterase agent, neostigmine methylsulfate, was determined using 125I-alpha-bungarotoxin. The total number of acetylcholine receptors on incubation day 12, 2 d subsequent to the onset of treatment, was reducted 45% as compared to saline-treated controls. A similar reduction in total receptor content (49%) was also observed on day 19. Radioautographic preparations showed that clusters of acetylcholine receptors were rare and that the grain density of extrajunctional receptors was also reduced. Hence, chronic treatment with neostigimine during development was observed to exert an effect on both the number and distribution of receptors in the developing superior oblique muscle. These changes occurred in the absence of any apparent effect on muscle differentiation in general. Myoblasts and myotubes were present on day 14 and further differentiated into myofibers by day 18 in both neostigmine and saline-treated muscles. The cytology of the develop;ing muscle cells also appeared normal. This is in contradistinction to the striking morphological changes that take place in adult mammalian and avian muscle after anticholinesterase treatment. More significantly, the decreased total receptor content and sparsity of clusters had no apparent effect on the formation of developing neuromuscular junctions at the electron microscopic level. The frequency of neuromuscular junctions in neostigmine-treated muscles was similar to that of the controls. It is concluded that acetylcholine receptor clusters are not required for the events leading to the morphological formation of neuromuscular junctions during in vivo development.

Intact peripheral target essential for branching of developing nerve fibers

Effects of the complete removal of the superior oblique muscle on the development of the trochlear nerve were studied by electron microscopy in white Peking duck embryos. Peripherally deprived nerves failed to show any evidence of branching, as did nerves taken from embryos whose neuromuscular transmission had been blocked with α-BTX. Our observations indicate that nerve branching may depend on a factor from the target tissue whose release or effectiveness is regulated by muscle activity. The possibility of a peripheral role in myelination of developing nerve fibers is also discussed.

Ultrastructural sequence of embryonic cell death in normal and peripherally deprived trochlear nucleus

The fine structural sequence of embryonic cell death which occurs during normal development and after removal of the peripheral target tissue was studied in the trochlear nucleus of white Peking duck embryos. The sequence of degeneration appears to be the same in both cases. The initial signs of degeneration appear in the cytoplasm in the form of dilation of the cisternae of the rough endoplasmic reticulum. Later, the dilation of this reticulum becomes remarkably increased and the mitochondria begin to show swelling and loss of cristae. The nuclear envelope at this stage becomes irregular, dilated, and disrupted. The nucleoplasm of such cells begins to show slight chromatin clumping, which later becomes extreme. Finally, the nuclear envelope disintegrates and the contents of the nucleus mix with those of the cytoplasm. Neuronal debris in the form of dense, compact globules is phagocytized by the glial elements. Similarities in the sequence of degeneration during normal development and after removal of the periphery suggest that the cause of cell death in both cases may be the same.

The Effect of Enforced Exposure to Live Models on The Reversibility of Attachments in White Peking Ducklings

Salzen’s (1962) neuronal model hypothesis of imprinting was tested using white peking ducklings and live hens with no previous maternal experiences as stimulus objects. One model was an adult white peking duck, and the other model was an adult rouen duck. The subjects were reared with their models for 24 hr. and tested for their preferences. They were then reared for an additional 24 hr. with the other model and again tested. The results indicated that the subjects reared with the rouen duck would not alter their initial preference. Subjects reared with the white peking model reversed their initial preference, but not to a statistically significant degree. The results do not completely support Salzen’s hypothesis.

Development of the trochlear nerve: Effects of early removal of periphery

Development of the trochlear nerve after early removal of the superior oblique muscle was studied in white Peking duck embryos. Unilateral optic vesicles together with the surrounding mesoderm were removed on Day 4 of incubation. Axon counts of the normal nerve indicate that the trochlear fibers sprout profusely shortly after contacting the periphery. Subsequently, large numbers of fibers are lost from the developing nerve. Most of the fiber loss appears to be via retraction. A significant number of trochlear neurons are also eliminated during this period. The direction of cell death may be from soma to axon. In the axon initial signs of degeneration appear in the axoplasm which are later followed by myelin deterioration. The peripherally deprived trochlear nerves grow properly to the region of their target organ. Nerve sprouting is delayed and occurs at a significantly reduced rate. Our observations indicate that nerve sprouting is triggered by the periphery. Some sort of interaction with the periphery appears to be necessary for myelination. Electrical stimulation on Day 26 of incubation indicates that the peripherally deprived trochlear fibers do not make inappropriate connections.