Differences in Tibia Shape in Organically Reared Chicken Lines Measured by Means of Geometric Morphometrics

Abstract

In the present study, the conformation of the tibia of seven genetic lines of broilers was analyzed by Geometric Morphometrics and correlated to carcass weight and walking ability. The used chicken genetic lines were classified as fast, medium, or slow growing and ranked for their walking ability. Six chicken types were reared in an organic farm and slaughtered at 81 days of age while one slow-growing and highly walking line (Naked Neck) was reared in a commercial farm and used as external reference for moving activity and growth speed. A mixed landmarks and semi-landmarks model was applied to the study of tibia shape. Results of this study showed that: (i) body weight gain was positively correlated to the curvature of the antero-posterior axis of the tibia; (ii) the shape of the tibia and the active walking behavior were significantly correlated; (iii) walking and not-walking genetic lines could be discriminated in relation to the overall shape of the tibia; (iv) a prevalence of static behavior was correlated to a more pronounced curvature of the antero-posterior axis of the tibia. Results of this study revealed that the walking genetic types have a more functional and natural tibia conformation. This easy morphologic method for evaluating tibia shape could help to characterize the adaptability of genotypes to organic and outdoor rearing.

Intake of nutrients (polyunsaturated fatty acids, tocols, and carotenes) and storage efficiency in different slow-growing chickens genotypes reared in extensive systems

“…Mancinelli et al [ 6 ] demonstrated that although a prerequisite of adaptability to ERS is a daily weight gain (DWG) below 45 g/d, the genotype can also affect this adaptability. Accordingly, slow weight gain is a prerequisite of adaptation, but SG chickens also differ in other aspects, such as walking and foraging behavior [ 8 , 9 , 12 , 13 ], demonstrating that interest in outdoor spaces strongly depends on the intrinsic behavior and genetics of animals.…”

Adaptability Challenges for Organic Broiler Chickens: A Commentary

“…It should be emphasized that the estimated improvement in animal welfare in OPP is achieved only if the right genetic chicken line is chosen [ 5 , 54 , 64 , 65 , 66 ]. As already shown in Section 2.1 , fast-growing broilers at an older age (81 d) are very heavy and have an unbalanced body conformation as a result of intense genetic selection for additional breast muscle and body mass, which render kinetic activity more difficult and unusual.…”

“…As already shown in Section 2.1 , fast-growing broilers at an older age (81 d) are very heavy and have an unbalanced body conformation as a result of intense genetic selection for additional breast muscle and body mass, which render kinetic activity more difficult and unusual. Many studies have recommended the use of slow-growing strains in OPP, which do not have the same welfare problems of the current commercial strains [ 5 , 65 , 67 ]. Slow-growing strains have lower mortality, less incidence of leg weakness and cardiovascular diseases, and generally show an improved welfare status [ 68 ].…”

“…In addition, bone health and gait scores can also be affected by the genotype. Slow-growing and active genotypes have better gait scores, better tibia conformation, and less tibial dyschondroplasia [ 65 , 67 , 89 , 90 , 91 ]. A study that compared the breast and gastrocnemius fiber muscle of two fast-growing lines reared in different housing conditions found that pathological changes were mainly seen in birds with outdoor access, and were indicative of their worse adaptability to the outdoors [ 92 , 93 ].…”

Tulang Tibia Ayam Kampung Super yang Diberi Pakan Mengandung Tepung Umbi Maek (Amorphophallus companulatus)

“…Tulang tibia adalah bagian anggota badan yang terdiri atas tulang tibia dan tulang fibula serta melakukan persendian secara langsung di ventral dengan tulang tarsal dan membentuk sendi tibiotarsal. Tulang tibia berfungsi untuk menopang tubuh ayam dan morfologi tulang tibia dipengaruhi oleh bobot badan badan ayam (Pulcini et al 2021). Koni dan Foenay (2015) menyatakan bahwa umbi AC fermentasi dengan ragi tempe dapat digunakan hingga 5% dalam pakan ayam pedaging.…”