Production and quality of products from laying hens in alternative rearing sustems

Rezime: U ovoj disertaciji je ispitivan uticaj alternativnih sistema gajenja na različite genotipove kokoši nosilja. Ogled je formiran po sistemu dvofaktorijalnog ogleda 2 x 2 (dva sistema gajenja - podni i sistem zasnovan prema principima organske proizvodnje i dva ispitivana genotipa - laki linijski hibrid Isa Brown i New Hampshire rasa). Ogled je trajao 54 sedmice. Tokom trajanja ogleda praćeni su sledeći proizvodni parametri: nosivost, dnevno proizvedena jajna masa, konzumacija i konverzija hrane i mortalitet. Kvalitet jaja je kontrolisan u toku sedam kontrolnih ispitivanja u pravilnim osmonedeljnim intervalima (24 – 72. nedelje starosti kokoši). Kod svakog jajeta ispitane su dve spoljašnje (masa jaja, indeks oblika) i pet unutrašnjih osobina njegovog kvaliteta (visina belanca, Hogove jedinice, boja žumanca, udeo belanca i udeo žumanca), kao i šest pokazatelja kvaliteta ljuske (udeo, debljina, deformacija, sila loma, boja i čistoća ljuske). Od parametara hemijskog sastava ispitivani su: sadržaj suve materije, pepela, proteina i masti, masnokiselinski sastav i sadržaj holesterola. Po završetku jednogodišnjeg proizvodnog ciklusa, na trupovima zaklanih jedinki utvrđeni su: masa i randman klasično obrađenog trupa i masa i udeo osnovnih delova trupa (grudi, bataci, karabataci, krila, leđa i karlica) u odnosu na živu masu kokoši pre klanja, kao i masa i udeo mesa u delovima trupa I kategorije (grudi, bataci, karabataci). Utvrđen je hemijski sastav belog i tamnog mesa: sadržaj suve materije, pepela, proteina i masti. Na butnoj kosti i golenjači je utvrđen kvalitet kostiju merenjem sile loma kostiju. Dobijeni rezultati su pokazali da su podno gajene New Hampshire kokoši imale najslabije proizvodne rezultate, nešto bolje rezultate su imale organski gajene jedinke istog genotipa, a najbolje Isa Brown ogledne grupe. Sistem gajenja je u pojedinim kontrolnim periodima značajno uticao na većinu parametara spoljašnjeg i unutrašnjeg kvaliteta jaja i neke od parametara kvaliteta ljuske, dok je tokom najvećeg dela trajanja oglednog perioda genotip značajno uticao na sve parametre unutrašnjeg i spoljašnjeg kvaliteta jaja i kvalitet ljuske. Za neke parametre kvaliteta jaja, u pojedinim fazama nosivosti, i interakcija sistem gajenja h genotip je pokazala signifikantan uticaj. Na parametre hemijskog sastava jaja, u pojedinim kontrolnim periodima, značajno su delovali i primenjeni sistem gajenja i korišćeni genotip, kao i interakcija ovih faktora. New Hampshire kokoši su imale veću masu trupa, osnovnih delova trupa, mesa u osnovnim delovima trupa u udeo leđa i karlice, dok je Isa Brown hibrid imao veći udeo krila. New Hampshire jedinke su imale veći sadržaj masti u mesu i veću silu loma kostiju u odnosu na Isa Brown genotip.Summary: The effect of alternative rearing systems on different genotypes of laying hens was studied in this thesis. The experiment was conducted according by two-factorial trial system 2 x 2 (two rearing systems - floor and the system designed according to the principles of organic production, and two genotypes - Isa Brown hybrid and New Hampshire breed). The experimental period lasted 54 weeks. During the experiment the following production parameters were monitored: egg production, daily egg mass produced, consumption and feed conversion and mortality. Egg quality was controlled during the seven control tests at regular intervals, an eight-week (24 - 72 weeks of age hens). For each egg tested two external (egg weight, shape index) and five internal properties of its quality (albumen height, Haugh units, yolk color, the share of whites and yolks share), as well as six shell quality indicators (share, thickness, deformation, breaking force, color and purity of the shell). The following chemical composition parameters were examined: dry matter, ash, protein and fat content, the fatty acid composition and cholesterol content. Upon completion of the one-year production cycle, on the carcasses of slaughtered laying hens were determined: weight and yield classically dressed carcass, weight and the share of main carcass parts (breasts, thighs, drumsticks, wings, back and pelvis) in relation to the live weight of hens before slaughter, and weight and share of meat in carcass parts of I category (breasts, thighs, drumsticks). Chemical composition of white and dark meat was determined: dry matter, ash, protein and fat content. At the femoral and tibial bone quality was determined by measuring the force of bone fracture. The results showed that the New Hampshire hens reared in floor system generally had the lowest production results, better results had organically reared birds of the same genotype, and the both Isa Brown experimental group had best production results. The rearing systems in certain control periods affected the majority of parameters of external and internal egg quality and some of the quality parameters of the shell, while for most of the duration of the experimental period genotype significantly affected all parameters of internal and external quality of eggs and shell quality. Interactions rearing systems to genotype showed a significant effect for some parameters of egg quality in certain control periods. Rearing system and genotype and the interaction of these factors significantly affected on the parameters of the chemical composition of eggs in certain control periods. New Hampshire laying hens had higher: carcass weight, weight of main parts the carcass, meat weight in the basic carcass parts, and the share of back and pelvis, while Isa Brown hybrid had a higher share of the wings. New Hampshire hens had a higher fat content in meat and greater bone fracture force in relation to the Isa Brown genotype