magistrsko delo
Tilen Kramer (Author), Janez Salobir (Reviewer), Dušan Terčič (Mentor), Manja Zupan (Co-mentor)

Abstract

V raziskavi smo ugotavljali vpliv 1,25 dihidroksivitamina D3 (kalcitriola) in izpostavljanja kokoši sončni svetlobi v obdobju od 18. do 74. tedna starosti na proizvodne lastnosti, kakovost jajc in kakovost kosti. Dvestoštirideset kokoši nesnic provenience Lohmann Brown smo po sistemu naključja razdelili v 4 tretmaje (A, B, C, D), znotraj vsakega tretmaja so bile 3 ponovitve, v vsaki ponovitvi se je nahajalo 20 kokoši. Tretmaji so bili naslednji: (A) osnovna krma, ki je vsebovala 75 µg vitamina D3/kg + reja kokoši v hlevu, (B) osnovna krma z dodatkom 1,0 µg kalcitriola/kg + reja kokoši v hlevu, (C) osnovna krma + enkrat tedensko spuščanje kokoši v čredinke, (D) osnovna krma z dodatkom 1,0 µg/kg kalcitriola + enkrat tedensko spuščanje kokoši v čredinke. Spremljali smo prirejo jac, porabo krme in kakovost jajc. Pri starosti 74 tednov smo iz vsakega tretmaja naključno izbrali 24 kokoši, jih stehtali, evtanazirali in z disekcijo trupov ločili stegnenico, golenico, nadlahtnico in grodnico. Omenjenim kostem smo izmerili dolžino, premer, lomno trdnost in jih stehtali. Niti dodatek kalcitriola v osnovno krmo, niti izpostavljanje kokoši sončni svetlobi, nista značilno (p⡥0,05) vplivala na telesno maso kokoši, zauživanje krme ter premer, gostoto in lomno trdnost kosti. Kokoši iz tretmajev B in D, kjer je bil v krmo dodan kalcitriol, so nesle jajca z značilno (p˂0,05) temnejšimi lupinami in manj intenzivno obarvanimi rumenjaki v primerjavi z jajci iz tretmaja A. Jajca kokoši iz tretmaja D so imela značilno (p˂0,05) šibkejše in tanjše lupine v primerjavi z jajci kokoši iz tretmaja B. V nasprotju s pričakovanji, dodatek kalcitriola in izpostavljanje kokoši sončni svetlobi nista prispevala k zmanjšanju obsega poškodb grodnice (p˂0,05).

Keywords

perutnina;kokoši;nesnice;prehrana živali;krmni dodatki;vitamin D;sončna svetloba;grodnica;stanje grodnice;proizvodne lastnosti;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [T. Kramer]
UDC: 636.5.084/.087(043.2)
COBISS: 91152131 Link will open in a new window
Views: 229
Downloads: 30
Average score: 0 (0 votes)
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Other data

Secondary language: English
Secondary title: Effects of dietary 1,25-dihydroxcholecalciferol and exposure to sunlight on keel bone status and production traits in laying hens
Secondary abstract: A study was conducted to investigate the effect of 1,25-dihydroxyvitamin D3 (calcitriol) and sunlight exposure of hens during the laying period (18-74 weeks) on laying hen performance, egg quality, and bone quality. A total of 240 Lohmann Brown laying hens were used in a randomized block trial with 4 treatments (A, B, C, D), 3 replicates per treatment, and 20 birds per replicate. Treatments were: (A) 75 µg/kg Vit D3 as control + indoor rearing, (B) control with additional 1.0 µg/kg calcitriol + indoor rearing, (C) control + once-weekly access to pasture, (D) control with additional 1.0 µg/kg calcitriol + once weekly access to pasture. We measured egg production, feed consumption and egg quality. At 74 weeks of age, 24 laying hens from each treatment were randomly selected, weighed, euthanized, and the femur, tibia, humerus, and keel bone were harvested to measure bone length, diameter, weight, and breaking strength. Neither calcitriol nor sun exposure affected (p⡥0.05) body weight, feed intake, bone diameter, bone density, and bone breaking strength. The addition of calcitriol resulted in significantly (p˂0.05) darker egg shells and less intensely coloured yolks in hens in treatments B and D compared to treatment A eggs. Hens of treatment D laid eggs with significantly weaker and thinner shells compared to hens of treatment B. Contrary to initial expectations, the supplementation of calcitriol and exposure of the hens to sunlight during the laying period did not reduce the prevalence of keel bone fractures.
Secondary keywords: poultry;laying hens;animal nutrition;feed additives;vitamin D;sunlight;keel bone status;production traits;
Type (COBISS): Master's thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za zootehniko
Pages: X, 68 f.
ID: 14129066