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Kerala Veterinary and Animal Sciences University, Wayanad

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Subject: Poultry Science × Start date: 2020 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    TRANSCRIPTOME ANALYSIS OF PECTORAL MUSCLE AMONG PEKIN AND KUTTANAD DUCKS
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2023-03-23) S. SANKARALINGAM; Dr. P. Anitha
    The study on “Transcriptome analysis of pectoral muscle among Pekin and Kuttanad ducks” was carried out at Department of Poultry Science, College of Veterinary and Animal Sciences, Mannuthy. The experimental birds of male Pekin, Kuttanad control and Kuttanad meat line ducks were reared up to eight weeks of ageand their production parameters, carcass characteristics, physicochemical attributes and compositional characters of meat were also measured from random samples of each replicate at four and eight weeks of age to find the differences among the three types of ducks. Along with that, all the above parameters of heavy- and low-weighing birds of each replicate were also measured in all three groups of ducks to correlate them with the data derived from transcriptome analysis of pectoral muscle of heavy- and low-weighing birds.The study on production parameters among Pekin duck, Kuttanad control population and Kuttanad meat line concludes that the Kuttanad selected line for meat had significant (p<0.05) improvement in body weight from the day-old to eight weeks of age compared to that of Kuttanad control population as a result of four generations of individual selection for eighth week body weight. The mean body weight gain of Kuttanad meat line was not significant compared to that of Kuttanad control population up to four weeks of age and it was significantly (p<0.05) higher at 5-6 weeks period which made the overall body weight gain up to eight weeks significant. During this period, the enrichment of differentially expressed genes (DEGs) for growth process was higher (3%) in GO analysis of transcriptome data between heavy- and low￾weighing birds of Kuttanad meat line while that of Kuttanad control population and Pekin duck were zero. The potential markers for enrichment of growth process in Kuttanad meat line were adrenoceptor alpha 2A (ADRA2A), dendrocyte expressed seven transmembrane protein (DCSTAMP), ventricular zone expressed PH domain containing 1 (VEPH1), dual oxidase 2 (DUOX2), maelstrom spermatogenic transposon silencer (MAEL), R-spondin 2 (RSPO2), acleraxis bHLH transcription factor (SCX), matrilin 1 (MATN1), forkhead box C1 (FOXC1), fibroblast growth factor 8 (FGF8) and growth differentiation factor 5 (GDF5) along with the nonsynonymous missense variant of SCX gene c.82G>C. The feed intake of Kuttanad meat line was significantly (p<0.5) more than that of Kuttanad control population after four weeks of age, this was due to the significant (p<0.05) increase in body weight gain of Kuttanad meat line after four weeks of age compared to Kuttanad control population. Even though there was significant (p<0.05) increase in body weight and weight gain in Kuttanad meat line compared to Kuttanad control population, the FCR was similar in both groups and less than that of Pekin duck. The FCR may improve in Kuttanad meat line, if the selection process is continued for few more generations.The study on carcass characteristics reveals that the eviscerated yield, breast yield, deboned breast yield, wings yield, neck yield, abdominal fat yield, heart yield, liver yield and gizzard yield percentage did not have any significant difference among the three types of ducks at four and eight weeks of age. The significant (p<0.05) increase in thigh yield percentage in the Kuttanad meat line compared to that of Kuttanad control group and Pekin duck indicates that the selection for eighth week body weight in Kuttanad duck resulted in significant (p<0.05) increase of thigh muscle compared to proportionate increase of other muscles. The study on physicochemical attributes of meat indicates that the selection for eighth week body weight significantly (p<0.05) improved the myofibril fragmentation index in breast muscle of Kuttanad meat line compared to Pekin duck. This study also concludes that the significantly (p<0.05) lower muscle fibre diameter and shear force in breast muscle compared to that of thigh muscle without affecting the sarcomere length could have led the breast muscle more tender than the thigh muscle. The study on compositional characteristics of meatconcludes that the selection for eighth week body weight significantly (p<0.05) improved the collagen solubility of thigh muscle in Kuttanad meat line compared to that of Pekin duck at four weeks of age. The transcriptome analysis of pectoral muscle of heavy- and low-weighing Kuttanad ducks at four weeks of age revealed that the downregulation of KIF24 gene in low-weighing Kuttanad meat line and its’ 20 SNPs and upregulation of CA3A and cystine/glutamate transporter-like (LOC116494038) genes in heavy-weighing Kuttanad meat line along with more enrichment in catalytic activity and cellular, metabolic, cellular component organization and growth processes could have contributed to the significant (p<0.05) growth of heavy-weighing Kuttanad meat line compared to that of low-weighing duck and also they may indirectly influence theevisceration percentage, deboned breast yield percentage, wings yield percentage and liver percentage and also improve the myofibril fragmentation index in breast muscle. This concludes that the fourth week body weight may also be considered along with selection for eighth week body weight to get more genetic gain per generation of selection. The same analysis at eight weeks of age revealed downregulation of TRIM7gene in heavy-weighing birds and its’ 25 SNPs; upregulation of GATM gene in heavy￾weighing birds and its’ 21 SNPs; upregulation of BCAR3 gene in heavy weighing Kuttanad meat line and its’ 15 SNPs; upregulation of AKR1D1 gene in heavy-weighing birds and its’ six SNPs; downregulation of NCEH1 gene in heavy-weighing Kuttanad meat line and its’ 18 SNPs and upregulation of CA3A, FRAS1, SLC25A48, LOC101802407, ACTC1 and ENAH genes in heavy-weighing birds and also downregulation of PPARGC1A, TAGAP, FAR2, MKNK1, NT5DC1, FABP3, DGAT2, ASB18 and GK genes in heavy-weighing birds along with more DEG enrichment in catalytic activity and cellular component organization, metabolic, biological phase, growth, locomotion, multi-organism process, biological adhesion and cell population proliferation processes could have contributed to significantly (p<0.05) higher eighth week body weight of heavy-weighing Kuttanad meat line compared to that of low￾weighing duck. The above potential markers may indirectly contribute to significant increase in breast, deboned breast, drumstick, abdominal fat and gizzard yield percentage and also higher myofibril fragmentation index of thigh muscle and muscle fibre diameter of breast muscle and reduction in shear force of breast and thigh muscles,which ultimately may increase the tenderness of the meat of Kuttanad meat line without affecting the compositional characters.The transcriptome analysis of pectoral muscle of heavy- and low-weighing Kuttanad control population at four weeks of age revealed significant downregulation of MYOM3 gene in low-weighing birds due to the presence of 29 SNPs and upregulation of METTL21C gene in low weighing Kuttanad duck control population due to the presence of four SNPs could have contributed to the significant (p<0.05) growth of heavy-weighing Kuttanad control population compared to that of low￾weighing birds at four weeks of age with more enrichment of catalytic activity and metabolic, multicellular organismal and biological regulation processes. The above potential markers may indirectly increase in evisceration percentage, breast, deboned breast, wings, neck and heart yield percentage and also numerical increase in muscle fibre diameter of breast muscle in Kuttanad control population without affecting the compositional characteristics. At eight weeks of age no significant DEG was identified from GO analysis of transcriptome data between heavy- and low-weighing duck of Kuttanad control population.The transcriptome analysis of pectoral muscle of heavy- and low-weighing commercial Pekin ducks at four weeks of age revealed significant downregulation of CCN3 gene in low-weighing Pekin duck due to the presence of seven SNPs and also upregulation of MATN1 gene in heavy-weighing duck along with more enrichment of transporter, structural molecule and molecular transducer activities and multicellular organismal, localization, locomotion, response to stimulus, signaling and biological adhesion processes could have contributed to significantly (p<0.05) higher growth of heavy-weighing Pekin duck compared to that of low-weighing duck at four weeks of age. The above potential markers may indirectly influence the significant (p<0.05) increase in evisceration, deboned breast, wings and gizzard percentage and also myofibril fragmentation index in Pekin duck without affecting the compositional characteristics. The same analysis at eight weeks of age revealed upregulation of ATP2A2 gene in heavy-weighing Pekin duck and presence of seven SNPs; upregulation of TNNI1 gene in heavy-weighing birds and itsfour SNPs; downregulation of MYBPC1gene in low-weighing Pekin duck and its 17 SNPs and also upregulation of CA3A/CA3, NR4A3, LMOD2, TFF2, IRX2, ACTC1 and ALB genes in heavy-weighing Pekin duck along with more enrichment of binding and transcription regulator activities and multicellular organismal, growth, locomotion, multi-organism, biological adhesion, cell population proliferation and immune system processes could have contributed to the significantly (p<0.05) higher body weight in heavy-weighing Pekin duck compared to that of low-weighing Pekin duck at eight weeks of age. The above potential markers may indirectly influence the significant (p<0.05) increase in muscle fibre diameter of thigh muscle of Kuttanad duck without affecting the compositional characteristics.The present study concludes that the Kuttanad meat line evolved from Kuttanad duck breed through selection for eighth week body weight over four generations is moving in the right direction of selection with moderate response. The response to selection is only around 250g body weight gain after four generations of individual selection which is not enough to cope up with the demand for duck meat. So, it is advisable to go for genomic selection using the candidate genes identified from this study along with the individual selection to improve growth, carcass characteristics, physicochemical attributes and compositional characteristics of Kuttanad meat line. It is advisable to go for combined selection for fourth and eight week body weight to get more genetic gain. This study also concludes that the above potential markers can be used for genomic selection in Kuttanad meat line, Kuttanad control population and commercial Pekin duck, respectively after validation of SNPs.