Ukuran dan Bentuk serta Pendugaan Potensi Bobot Badan Ayam IPB dan Ayam Kampung pada Periode Starter dan Grower

Abstract

Ayam IPB D1 merupakan rumpun baru ayam lokal komposit yang memiliki keunggulan performa pertumbuhan dan reproduksi yang lebih baik dari ayam kampung. Ayam IPB D2 dan ayam IPB D3 merupakan ayam IPB D1 yang diseleksi terhadap sifat ketahanan Newcastle Disease (ND) dan sifat bobot badan tinggi. Perbandingan morfometrik ukuran permukaan tubuh linear dan pendugaan bobot badan pada ayam kampung, ayam IPB D1 G11, ayam IPB D2 G5, dan ayam IPB D3 G4, belum dilakukan. Penelitian ini bertujuan menentukan perbandingan ukuran (size) dan bentuk (shape) tubuh pada ayam kampung, ayam IPB D1, ayam IPB D2, dan ayam IPB D3 berdasarkan diagram kerumunan pada periode starter dan grower dan pendugaan potensi bobot badan berdasarkan ukuran permukaan tubuh linear yang berkaitan erat dengan proses adaptasi sebagai produk seleksi alam. Penelitian ini menggunakan ayam kampung (75 jantan dan 96 betina), ayam IPB D1 (4 jantan dan 17 betina), ayam IPB D2 (32 jantan dan 52 betina), dan ayam IPB D3 (30 jantan dan 47 betina) periode starter. Periode grower digunakan ayam kampung (57 jantan dan 83 betina), ayam IPB D1 (12 jantan dan 55 betina), ayam IPB D2 (65 jantan dan 148 betina), dan ayam IPB D3 (67 jantan dan 206 betina). Variabel ukuran-ukuran permukaan tubuh linear yang diamati meliputi panjang femur (X1), panjang tibia (X2), panjang tarsometatarsus (X3), lingkar tarsometatarsus (X4), panjang jari ketiga (X5), panjang sayap (X6), panjang maxilla (X7), dan tinggi jengger (X8). Perbandingan ukuran dan bentuk tubuh dilakukan berdasarkan analisis komponen utama (AKU). Potensi bobot badan diduga melalui analisis regresi komponen utama (ARKU) berdasarkan pengukuran delapan variabel ukuran permukaan tubuh linear tersebut. Hasil penelitian menunjukkan bahwa penciri ukuran (size) tubuh adalah panjang sayap dan penciri bentuk (shape) tubuh ayam adalah tinggi jengger pada ayam kampung, ayam IPB D1, ayam IPB D2, dan ayam IPB D3. Bentuk tubuh periode starter ayam IPB D1 jantan dan ayam IPB D2 jantan ditemukan mirip, sedangkan pada betina bentuk tubuh ayam IPB D2 dan ayam IPB D3 ditemukan mirip. Pergeseran kerumunan data ayam periode grower pada ayam IPB D3 jantan ditemukan ke arah atas, sedangkan kerumunan data ayam IPB D2 jantan ditemukan ke arah bawah. Panjang sayap memiliki keterkaitan terbesar terhadap bobot badan pada semua ayam yang diamati dibandingkan dengan variabel ukuran permukaan tubuh lain yang diamati. Ayam IPB D1 secara genetis bersifat responsif untuk bobot badan terhadap seleksi alam dan tampil lebih unggul dibandingkan ayam kampung. Ayam IPB D2 betina secara genetis memiliki potensi bobot badan yang hampir sama dengan ayam IPB D1 betina. Bobot badan pada ayam IPB D3 lebih banyak dipengaruhi faktor selain ukuran permukaan tubuh linear yang diamati. Ayam IPB D3 diduga dapat memperlihatkan respons baik bila dipelihara secara intensif.

IPB D1 chickens are a new breed of composite indigenous chickens with the advantage of better growth and reproductive performance than indigenous chickens. IPB D2 and IPB D3 chickens are IPB D1 chickens selected for Newcastle Disease (ND) resistance and high body weight traits. A morphometric comparison of linear body surface area and body weight estimation in indigenous chickens, IPB D1 G11 chickens, IPB D2 G5 chickens and IPB D3 G4 chickens has not been performed. The aim of this study is to determine the comparison of body size and shape in indigenous chickens, IPB D1 chickens, IPB D2 chickens and IPB D3 chickens based on crowd diagrams in the starter and grower periods and the estimation of potential body weight based on linear body surface area, which is closely related to the adaptation process as a product of natural selection. This study used native chickens (75 males and 96 females), IPB D1 chickens (4 males and 17 females), IPB D2 chickens (32 males and 52 females) and IPB D3 chickens (30 males and 47 females) in the starter period. Native chickens (57 males and 83 females), IPB D1 chickens (12 males and 55 females), IPB D2 chickens (65 males and 148 females) and IPB D3 chickens (67 males and 206 females) were used in the growing period. Linear body surface size variables observed included femur length (X1), tibia length (X2), tarsometatarsal length (X3), tarsometatarsal circumference (X4), third digit length (X5), wing length (X6), maxilla length (X7) and cockscomb height (X8). Comparisons of body size and shape were made using Principal Component Analysis (PCA). Potential body weight was estimated by principal component regression analysis (PCRA) based on measurements of the eight linear body surface size variables. The results showed that the characteristic of body size was wing length and the characteristic of body shape was cockscomb height in native chickens, IPB D1 chickens, IPB D2 chickens and IPB D3 chickens. The body shape of starter period male IPB D1 chickens and male IPB D2 chickens was found to be similar, while in females the shape of IPB D2 chickens and IPB D3 chickens was similar. The crowding shift of the rearing period in male IPB D3 chickens was found to be upward, while the crowding shift of the rearing period in male IPB D2 chickens was found to be downward. Wing length had the strongest relationship with body weight for all chickens observed compared to other observed body surface area variables. IPB D1 chickens are genetically responsive to natural selection for body weight and perform better than indigenous chickens. Female IPB D2 chickens have almost the same genetic potential for body weight as female IPB D1 chickens. Body weight in IPB D3 chickens is more influenced by factors other than the observed linear body surface area. It is expected that IPB D3 chickens will respond well to intensive management.